Journal articles on the topic 'Repeat aerial photography'

AbstractHorizontal velocity measurements on the lower part of Engabreen, Norway, were made from repeat aerial photography. IMCORR software, which has been widely used to measure velocities from satellite images, was used to make the measurements. This is the first known successful use of IMCORR on aerial photographs. Supplementary horizontal velocity measurements were made from repeat measurements of stakes, giving velocities over different periods and also in areas that are too slow-moving to register a measurable velocity after only a few days.

Time series of repeat aerial photographs currently span decades in many regions. However, the lack of calibration data limits their use in forest change analysis. We propose an approach where we combine repeat aerial photography, tree-ring reconstructions, and Bayesian inference to study changes in forests. Using stereopairs of aerial photographs from five boreal forest landscapes, we visually interpreted canopy cover in contiguous 0.1-ha cells at three time points during 1959–2011. We used tree-ring measurements to produce calibration data for the interpretation, and to quantify the bias and error associated with the interpretation. Then, we discerned credible canopy cover changes from the interpretation error noise using Bayesian inference. We underestimated canopy cover using the historical low-quality photographs, and overestimated it using the recent high-quality photographs. Further, due to differences in tree species composition and canopy cover in the cells, the interpretation bias varied between the landscapes. In addition, the random interpretation error varied between and within the landscapes. Due to the varying bias and error, the magnitude of credibly detectable canopy cover change in the 0.1-ha cells depended on the studied time interval and landscape, ranging from −10 to −18 percentage points (decrease), and from +10 to +19 percentage points (increase). Hence, changes occurring at stand scales were detectable, but smaller scale changes could not be separated from the error noise. Besides the abrupt changes, also slow continuous canopy cover changes could be detected with the proposed approach. Given the wide availability of historical aerial photographs, the proposed approach can be applied for forest change analysis in biomes where tree-rings form, while accounting for the bias and error in aerial photo interpretation.

Norway has a political goal to minimize the loss of cultural heritage due to removal, destruction or decay. On behalf of the national Directorate for Cultural Heritage, we have developed methods to monitor Cultural Heritage Environments. The complementary set of methods includes (1) landscape mapping through interpretation of aerial photographs, including field control of the map data, (2) qualitative and quantitative initial and repeat landscape photography, (3) field recording of cultural heritage objects including preparatory analysis of public statistical data, and (4) recording of stakeholder attitudes, perceptions and opinions. We applied these methods for the first time to the historical clustered farm settlement of Havrå in Hordaland County, West Norway. The methods are documented in a handbook and can be applied as a toolbox, where different monitoring methods or frequency of repeat recording may be selected, dependent on local situations, e.g., on the landscape character of the area in focus.

In September 2014 the Applied Geomatics Research Group (AGRG) completed a third aerial mapping campaign of Sable Island. The AGRG first mapped the island in October 2002 with an aerial photography survey. Then in August 2009 AGRG conducted an aerial photography and Light Detection And Ranging (LiDAR) survey. Five years later these same technologies were deployed again. Each of these surveys led to an orthophoto mosaic of the island and a mapping of the land cover. The 2009 and 2014 surveys also mapped the island’s topography using Digital Surface Models (DSMs) derived from the LiDAR data. Ground-truthing efforts associated with each survey provided data to assist with the interpretation and validation of the results.The repeat surveys resulted in an excellent opportunity to quantify the topographic and land cover changes that have occurred on the island. The mapped results provide a comparison of how and where these changes have occurred over the years. AGRG is working with Parks Canada to better understand how the topography and land cover are changing. This understanding will contribute to Parks Canada Ecological Integrity monitoring program for Sable Island and inform the management planning process for one of Canada’s newest national parks.

AbstractThe tectonic effects of a glacier surge differ from those of steady state because flow is driven by longitudinal stresses rather than shear stresses. The orientations of recently formed crevasses, indicating the directions of the principal stresses, have been used to investigate tectonic processes in glacier surges recorded by repeat aerial photography. Long-term, large-magnitude shifts in stress regime are demonstrated, as are short-term propagation features. Two types of tide-water glacier advance are identified, depending on the position of the surge front relative to a low effective-pressure zone at the glacier terminus.

AbstractThe tectonic effects of a glacier surge differ from those of steady state because flow is driven by longitudinal stresses rather than shear stresses. The orientations of recently formed crevasses, indicating the directions of the principal stresses, have been used to investigate tectonic processes in glacier surges recorded by repeat aerial photography. Long-term, large-magnitude shifts in stress regime are demonstrated, as are short-term propagation features. Two types of tide-water glacier advance are identified, depending on the position of the surge front relative to a low effective-pressure zone at the glacier terminus.

Beavers are often described as ecological engineers with an ability to modify the structure and flow of fluvial systems and create complex wetland environments with dams, ponds, and canals. Consequently, beaver activity has implications for a wide range of environmental ecosystem services including biodiversity, flood risk mitigation, water quality, and sustainable drinking water provision. With the current debate surrounding the reintroduction of beavers into the United Kingdom, it is critical to be able to monitor the impact of beavers upon the environment. This study presents the first proof of concept results showing how a lightweight hexacopter fitted with a simple digital camera can be used to derive orthophoto and digital surface model (DSM) data products at a site where beavers have recently been reintroduced. Early results indicate that analysis of the fine-scale (0.01 m) orthophoto and DSM can be used to identify impacts on the ecosystem structure including the extent of dams and associated ponds, and changes in vegetation structure due to beaver tree-felling activity. Unmanned aerial vehicle data acquisition offers an effective toolkit for regular repeat monitoring at fine spatial resolution, which is a critical attribute for monitoring rapidly changing and difficult to access beaver-impacted ecosystems.

The relations between seasonal changes in ice speed, longitudinal extension rate and terminus position are investigated for Columbia Glacier, Alaska, over the period 1977–87. The lower reach of the glacier is studied using repeat aerial photography, which extends from the terminus to the base of an icefall about 14 km up-glacier. There are regular seasonal cycles in speed and stretching rate. These cycles continue after the glacier retreats off the shoal at the end of the fjord (in about 1983), indicating that factors other than backstress, such as seasonal changes in subglacial water, control the speed of the glacier. Terminus position appears to be linked with thinning induced by longitudinal extension, as predicted by the calving model proposed by Van der Veen (1996).

The relations between seasonal changes in ice speed, longitudinal extension rate and terminus position are investigated for Columbia Glacier, Alaska, over the period 1977–87. The lower reach of the glacier is studied using repeat aerial photography, which extends from the terminus to the base of an icefall about 14 km up-glacier. There are regular seasonal cycles in speed and stretching rate. These cycles continue after the glacier retreats off the shoal at the end of the fjord (in about 1983), indicating that factors other than backstress, such as seasonal changes in subglacial water, control the speed of the glacier. Terminus position appears to be linked with thinning induced by longitudinal extension, as predicted by the calving model proposed by Van der Veen (1996).

The United States-Mexico international boundary from ElPaso, Texas to the Pacific Coast shows clear differences in plant communities that were homogeneous prior to being split by a continuous fence at the turn of the century. This study evaluates how disparate fire regimes in California (fire suppression) and northern Baja California (little or no fire control) have influenced succession in the chamise (Adenostoma fasciculatum) chaparral communities spanning the international boundary between the border towns of Jacume and Tecate. Fire history was reconstructed using U.S. Forest Service fire maps and repeat aerial photography. Once plotted onto topographic maps and dated, the burns were divided into age-classes and sampled using 50 m point-quarter transects to develop successional chronosequences. Although fires are more frequent and smaller on the Mexican side of the border, our repeat photographs of the boundary monument markers together with field samples show that chaparral succession is similar across the international boundary in species composition, stem densities, and average mass shrub height. Chamise chaparral appears to be stable under disparate fire regimes because sprouting habits and latent seed pools permit efficient stand establishment under either short or long fire intervals. Chaparral recovery during the period examined here is unrelated to fire size because recolonization of burns by long-range seed dispersal is not a trait of the majority of the local shrub species and the shrubs either resprout. or germinate from soil seed reservoirs.

M.V. Nella Dan was beset in ice near 66°S, 51°Ε from 27 October to 15 December 1985. The scientific investigations planned for the voyage into the sea-ice zone included ice thickness, concentration and extent measurements, aerial photography of the ice, a core drilling project and meteorological observations. Once beset, the programme was expanded to include repeat measurements of a small strain grid and measurements of the sea-ice drift rate. Strongly convergent local conditions had led to the initial besetment of the ship. Analysis of measurements of the strain grid area over an 11 d period shows that, although there is some indication that the ice field may have been divergent, opening by approximately 3.4% over this period, there are large errors in the measurements and some doubt must be placed on the reliability of this estimate. The drift speed and direction were found to be highly dependent on wind speed and direction, the drift rate being approximately 2.7% of the wind speed at an angle of about 29° to the left of the wind direction.

M.V.Nella Danwas beset in ice near 66°S, 51°Ε from 27 October to 15 December 1985. The scientific investigations planned for the voyage into the sea-ice zone included ice thickness, concentration and extent measurements, aerial photography of the ice, a core drilling project and meteorological observations. Once beset, the programme was expanded to include repeat measurements of a small strain grid and measurements of the sea-ice drift rate. Strongly convergent local conditions had led to the initial besetment of the ship. Analysis of measurements of the strain grid area over an 11 d period shows that, although there is some indication that the ice field may have been divergent, opening by approximately 3.4% over this period, there are large errors in the measurements and some doubt must be placed on the reliability of this estimate. The drift speed and direction were found to be highly dependent on wind speed and direction, the drift rate being approximately 2.7% of the wind speed at an angle of about 29° to the left of the wind direction.

AbstractA systematic review of 1959/60 aerial photography, and 1999/2000 Landsat 7 imagery, has identified 51 surge-type polythermal glaciers in the Canadian High Arctic. These were identified from the presence of features such as looped medial moraines, intense folding visible at the surface, rapid terminus advance, heavy surface crevassing, and high surface velocities. These observations suggest that surging glaciers are much more common than previously believed in the Canadian High Arctic, where only six surge-type glaciers have previously been described. Of the 51 surge-type glaciers identified in this study, 15 were observed in the active phase in the 1959/60 and/or 1999/2000 imagery. The most dramatic advances have occurred on western Axel Heiberg Island, where Iceberg,“Good Friday Bay” and Airdrop Glaciers have all advanced by 4–7 km between1959 and 1999. For glaciers with repeat Landsat 7 coverage from 1999 and 2000, image correlation software was used to determine the magnitude and spatial distribution of surge velocities. For example,“Mittie” Glacier on Manson Icefield was moving at a rate of up to 1 kma–over a distance of at least 25 km back from its terminus. The terminus of this glacier has advanced by at least 4 km since 1959, and the glacier was observed to be heavily crevassed during overflights in April 2000, with clear signs of surface lowering of 10–25 m indicated by a strandline.

Purpose The purpose of this paper is to describe the procedure for near-automation of the most commonly used manual georeferencing technique in a desktop GIS environment for historic aerial photographs strip in library archives. Design/methodology/approach Most of the archived historic aerial photography consists of series of aerial photographs that overlap to some extent, as the optimal overlap ratio is known as 60 percent by photogrammetric standard. Therefore, conjugate points can be detected for the overlapping area. The first image was georeferenced manually by six-parameter affine transformation using 2013 National Agriculture Imagery Program images as ground truths. Then, conjugate points were detected in the first and second images using Speeded Up Robust Features and Random Sample Consensus. The ground space coordinates of conjugate points were estimated using the first image’s six parameters. Then the second image’s six parameters were calculated using conjugate points’ ground space coordinates and pixel coordinates in the second image. This procedure was repeated until the last image was georeferenced. However, error accumulated as the number of photographs increased. Therefore, another six-parameter affine transformation was implemented using control points in the first, middle, and last images. Finally, the images were warped using open source GIS tools. Findings The result shows that historic aerial strip collections can be georeferenced with far less time and labor using the technique proposed compared with the traditional manual georeferencing technique in a desktop GIS environment. Research limitations/implications The suggested approach will promote the usage of historic aerial photographs for various scientific purposes including land use and land cover change detection, soil erosion pattern recognition, agricultural practices change analysis, environmental improvement assessment, and natural habitat change detection. Practical implications Most commonly used georeferencing procedures for historic aerial photographs in academic libraries require significant time and effort for manual measurement of conjugate points in the object images and the ground truth images. By maximizing the automation of georeferencing procedures, the suggested approach will save significant time and effort of library workforce. Social implications With the suggested approach, large numbers of historic aerial photographs can be rapidly georeferenced. This will allow libraries to provide more geospatial data to scientific communities. Originality/value This is a unique approach to rapid georeferencing of historic aerial photograph strips.

The Carpentarian Rock-rat Zyzomys palatalis is a rare conilurine rodent with a global distribution restricted to a small area of sandstone escarpments in the Gulf of Carpentaria region of the Northern Territory. Previous assessments of its World Conservation Union (IUCN) status in 1996 had classified the species as Critically Endangered based on the restricted area of occupancy and a putative decline in the extent and quality of its closed forest habitat due to uncontrolled landscape fires. A later population viability analysis confirmed that habitat loss was potentially the single most important threatening process. Here we argue that the species should be reclassified as Vulnerable, on the basis of the following new evidence: (1) the assumption that it was a closed forest specialist was not supported by a radiotracking study, which showed that on average 43% of an individual's monitored time was spent in the forest-savannah margin, and (2) analysis of repeat historical aerial photography has shown that the core closed forest habitat has in fact increased by 36% over the last 50 years. This has lead to an increase of 140 in the minimum number of equivalent Z. paJatalis territories, from 387 to 587, when home range overlaps and utilization of the savannah margins are considered. Reclassification of the species' conservation status should be accompanied with: (i) genetic studies of relatedness between isolated populations; (ii) monitoring and maintenance of the integrity of the landscapes, including creeklines that connect patches; and (iii) consideration of the introduction of captive bred specimens into an adjacent unoccupied fragments.

AbstractOn 22 March 2014, a massive, catastrophic landslide occurred near Oso, Washington, USA, sweeping more than 1 km across the adjacent valley flats and killing 43 people. For the following 5 weeks, hundreds of workers engaged in an exhaustive search, rescue, and recovery effort directly in the landslide runout path. These workers could not avoid the risks posed by additional large-scale slope collapses. In an effort to ensure worker safety, multiple agencies cooperated to swiftly deploy a monitoring and alerting system consisting of sensors, automated data processing and web-based display, along with defined communication protocols and clear calls to action for emergency management and search personnel. Guided by the principle that an accelerating landslide poses a greater threat than a steadily moving or stationary mass, the system was designed to detect ground motion and vibration using complementary monitoring techniques. Near real-time information was provided by continuous GPS, seismometers/geophones, and extensometers. This information was augmented by repeat-assessment techniques such as terrestrial and aerial laser scanning and time-lapse photography. Fortunately, no major additional landsliding occurred. However, we did detect small headscarp failures as well as slow movement of the remaining landslide mass with the monitoring system. This was an exceptional response situation and the lessons learned are applicable to other landslide disaster crises. They underscore the need for cogent landslide expertise and ready-to-deploy monitoring equipment, the value of using redundant monitoring techniques with distinct goals, the benefit of clearly defined communication protocols, and the importance of continued research into forecasting landslide behavior to allow timely warning.

During the twentieth century, the 20,000 hectares commons surrounding the village of Paulshoek as well as the neighbouring privately-owned farms have been significantly influenced by evolving land-use practices driven largely by socio-economic and political change in the broader Namaqualand and South African region. Land-use practices in the communal lands of Namaqualand were based initially on transhumant pastoralism, then on extensive dryland cropping associated with livestock production under restricted mobility, and more recently on a sedentarized labour reserve where agricultural production now forms a minor part of the local economy. For the first half of the twentieth century, farmers on communal and privately-owned farms shared similar transhumant pastoral practices and both moved across unfenced farm boundaries. By the middle of the century, however, fence-lines were established and commercial farming on privately-owned farms was increasingly managed according to rangeland science principles. As the population grew in the communal areas, families gravitated to new ‘service’ villages such as Paulshoek and became increasingly dependent on migrant labour and state welfare. While the majority of former croplands are now fallow, many of them for decades or more, communal livestock populations have remained relatively high, fluctuating with rainfall. The impact of this history of land use can be compared with that of neighbouring privately-owned farms where low stocking rates, coupled with a variety of state subsidies, have had a very different environmental outcome. This article charts the environmental transformations that have occurred in the area of Paulshoek as a direct result of the region's political history and the evolution of the regional economy. We present a variety of evidence drawn from archival sources, oral history, repeat aerial and ground photography, and detailed climate, cropping and livestock records to show that events far beyond the borders of Namaqualand's communal areas have had a profound influence on their environments.

Aerial photography is often impossible due to the presence of high clouds with contrasting shadows that do not allow to obtain materials suitable for decryption. At the same time, in a significant proportion of projects in Russia, the snowless season suitable for surveying is very short. The inability to perform aerial photography while flying below the clouds leads to cost increasing. In some cases, projects cannot be completed. Existing software does not allow to solve the problem of equalizing the brightness in the shadows for several reasons. The main reason is the inability to identify the boundaries of the shadows using only the spectral characteristics of the images, the inability to determine the amount of correction for shaded areas. To solve this problem, it is proposed to use reference images of the worse resolution obtained from the satellites. Reference images are used to localize and determine the magnitude of the spectral correction of aerial photographs. The work is performed with single orthophotographs or orthophotomosaics in the same coordinate system. To determine the boundaries of the shaded zones and the values of the corrections in brightness, methods of cartographic algebra on regular data arrays are used. Further, the obtained correction matrices are subject to filtering and are used to correct high-resolution aerial photographs. The paper gives an example of the use of free (or cheap) satellite images to eliminate or reduce the contrast of shadows on aerial photographs with a detail of 20 cm. The created prototype software allows to perform additive or multiplicative correction of an array of individual aerial photographs. The proposed approach requires more time for data processing, but gives much more acceptable results for visual (manual) decryption. The method is not recommended for use when working with images in more than 10 cm, when solving monitoring tasks with frequent repeated surveys, and also, if necessary, to carry out automated decoding using spectral standards.

Northern environments are changing in response to recent climate warming, resource development, and natural disturbances. The Arctic climate has warmed by 2&ndash;3°C since the 1950’s, causing a range of cryospheric changes including declines in sea ice extent, snow cover duration, and glacier mass, and warming permafrost. The terrestrial Arctic has also undergone significant temperature-driven changes in the form of increased thermokarst, larger tundra fires, and enhanced shrub growth. Monitoring these changes to inform land managers and decision makers is challenging due to the vast spatial extents involved and difficult access. <br><br> Environmental monitoring in Canada’s North is often based on local-scale measurements derived from aerial reconnaissance and photography, and ecological, hydrologic, and geologic sampling and surveying. Satellite remote sensing can provide a complementary tool for more spatially comprehensive monitoring but at coarser spatial resolutions. Satellite remote sensing has been used to map Arctic landscape changes related to vegetation productivity, lake expansion and drainage, glacier retreat, thermokarst, and wildfire activity. However, a current limitation with existing satellite-based techniques is the measurement gap between field measurements and high resolution satellite imagery. Bridging this gap is important for scaling up field measurements to landscape levels, and validating and calibrating satellite-based analyses. This gap can be filled to a certain extent using helicopter or fixed-wing aerial surveys, but at a cost that is often prohibitive. <br><br> Unmanned aerial vehicle (UAV) technology has only recently progressed to the point where it can provide an inexpensive and efficient means of capturing imagery at this middle scale of measurement with detail that is adequate to interpret Arctic vegetation (i.e. 1&ndash;5 cm) and coverage that can be directly related to satellite imagery (1&ndash;10 km²). Unlike satellite measurements, UAVs permit frequent surveys (e.g. for monitoring vegetation phenology, fires, and hydrology), are not constrained by repeat cycle or cloud cover, can be rapidly deployed following a significant event, and are better suited than manned aircraft for mapping small areas. UAVs are becoming more common for agriculture, law enforcement, and marketing, but their use in the Arctic is still rare and represents untapped technology for northern mapping, monitoring, and environmental research. <br><br> We are conducting surveys over a range of sensitive or changing northern landscapes using a variety of UAV multicopter platforms and small sensors. Survey targets include retrogressive thaw slumps, tundra shrub vegetation, recently burned vegetation, road infrastructure, and snow. Working with scientific partners involved in northern monitoring programs (NWT CIMP, CHARS, NASA ABOVE, NRCan-GSC) we are investigating the advantages, challenges, and best practices for acquiring high resolution imagery from multicopters to create detailed orthomosaics and co-registered 3D terrain models. Colour and multispectral orthomosaics are being integrated with field measurements and satellite imagery to conduct spatial scaling of environmental parameters. Highly detailed digital terrain models derived using structure from motion (SfM) photogrammetry are being applied to measure thaw slump morphology and change, snow depth, tundra vegetation structure, and surface condition of road infrastructure. <br><br> These surveys and monitoring applications demonstrate that UAV-based photogrammetry is poised to make a rapid contribution to a wide range of northern monitoring and research applications.

Repeat ground photographs (taken in 1915 and 1997) from a series of topographical survey stations and repeat aerial photographs (flown in 1949 and 1991) were analysed to assess changes in vegetation composition and distribution in the montane ecoregion of Jasper National Park, in the Rocky Mountains of Alberta, Canada. A quantitative approach for assessing relative vegetation change in repeat ground photographs was developed and tested. The results indicated a shift towards late-successional vegetation types and an increase in crown closure in coniferous stands. Grasslands, shrub, juvenile forest, and open forests decreased in extent, and closed-canopy forests became more prevalent. The majority of forest stands succeeded to dominance by coniferous species. Changes in vegetation patterns were likely largely attributable to shifts in the fire regime over the last century, although climatic conditions and human activity may also have been contributing factors. Implications of observed changes include decreased habitat diversity, increased possibility of insect outbreaks, and potential for future high-intensity fire events. Results of the study increase knowledge of historical reference conditions and may help to establish restoration goals for the montane ecoregion of the park.

The production of residual white ash patches within wildfires represents near-complete combustion of the available fuel and releases a considerable quantity of gases to the atmosphere. These patches are generally produced from combustion of large downed woody debris (LDWD) such as fallen trees and snags. However, LDWD are generally ignored in calculations of fuel combusted within environments where surface fires dominate (e.g. southern African savannas). To assess the potential of fractional white ash cover as a remotely sensed measure of LDWD combustion, both the proportion of the surface covered by white ash and the combustion completeness required to produce white ash must be quantified. An aerial photograph of woodland savanna fires in north-western Zimbabwe was analysed to estimate the proportion of white ash cover within a typical satellite sensor pixel. The proportion loss on ignition (LOI) of wood samples from the study area was measured and combined with previous estimates of mean tree biomass. The proportion of white ash within the aerial photographs was 0.2% (± 0.06), which corresponded to an additional 67 320 kg ha−1 of biomass combusted above that typically recorded as combusted from a surface fire in this environment (~7000 kg ha−1). This analysis should be repeated in other savannas and forests, where pre-fire fuel loads and post-fire fractional white ash cover may be higher.

Plot-scale field measurements are necessary to monitor changes to tundra vegetation, which has a small stature and high spatial heterogeneity, while satellite remote sensing can be used to track coarser changes over larger regions. In this study, we explored the potential of unmanned aerial vehicle (UAV) photographic surveys to map low-Arctic vegetation at an intermediate scale. A multicopter was used to capture highly overlapping, subcentimetre photographs over a 2 ha site near Tuktoyaktuk, Northwest Territories. Images were processed into ultradense 3D point clouds and 1 cm resolution orthomosaics and vegetation height models using Structure-from-Motion (SfM) methods. Shrub vegetation heights measured on the ground were accurately represented using SfM point cloud data (r2 = 0.96, SE = 8 cm, n = 31) and a combination of spectral and height predictor variables yielded an 11-class classification with 82% overall accuracy. Differencing repeat UAV surveys before and after manually trimming shrub patches showed that vegetation height decreases in trimmed areas (− 6.5 cm, SD = 21 cm). Based on these findings, we conclude that UAV photogrammetry provides a promising, cost-efficient method for high-resolution mapping and monitoring of tundra vegetation that can be used to bridge the gap between plot and satellite remote sensing measurements.

Analyses of historical aerial photographs from 1957 to 2003 were combined with two molecular techniques to examine population structure of the swamp paperbark (Melaleuca ericifolia Sm., Myrtaceae) in Dowd Morass, a large, brackish-water wetland of the Gippsland Lakes, Australia. Molecular markers (microsatellites and inter-simple sequence repeats) demonstrated that the large, dome-shaped stands of M. ericifolia evident in the field were individual genets and that adjacent genets did not intermingle. The development of 18 individual stands visible in aerial photographs from 1964 to 2003, but absent from 1957 images, allowed us to calculate that stands expanded at (individual) mean rates of 25–77 m2 year–1 over the period 1964–2003. Rates of lateral expansion, however, varied significantly between 1964 and 2003; the mean rates were highest in 1978–1982 and 1982–1991 (75 ± 7 and 73 ± 9 m2 year–1, respectively) and significantly lower in 1991–2003 (45 ± 3 m2 year–1). A slowing of lateral expansion rate may indicate stand senescence, although competition and space limitations as clones abut each other may also be relevant processes. Clonality has several important implications for the conservation and rehabilitation of Melaleuca-dominated wetlands in south-eastern Australia, including the ability of plants to maintain themselves under adverse hydrological and salinity regimes.

AbstractWe investigate velocity changes occurring along Whillans Ice Stream (WIS) by comparing velocities derived from repeat aerial photographs acquired in 1985-89 (average date of 1987) to interferometric satellite radar (InSAR) velocities collected in 1997. Three different analysis methods are applied to the velocity data. First, temporal and spatial changes in velocities are correlated to identifiable features (flowlines, shear margins, bed features) visible on the 1997 RADARSAT Antarctic Mapping Project mosaic. Second, we relate velocity gradients to stresses via the flow law and, along with surface topography and ice-thickness data, apply the force-budget technique to determine the relative importance of driving stress, side drag and basal drag over time. Finally, the mass balance of the main part of WIS is determined for 1987 and 1997. Our results are consistent with previous studies that show an overall deceleration resulting in downstream thickening of the ice stream (Whillans and others, 2001; Joughin and others, 2002).

Plateau pika (Ochotona curzoniae, hereafter pika) is considered to exert a profound impact on vegetation species diversity of alpine grasslands. Great efforts have been made at mound or quadrat scales; nevertheless, there is still controversy about the effect of pika. It is vital to monitor vegetation species composition in natural heterogeneous ecosystems at a large scale to accurately evaluate the real role of pika. In this study, we performed field survey at 55 alpine grassland sites across the Shule River Basin using combined methods of aerial photographing using an unmanned aerial vehicle (UAV) and traditional ground measurement. Based on our UAV operation system, Fragmentation Monitoring and Analysis with aerial Photography (FragMAP), aerial images were acquired. Plot-scale vegetation species were visually identified, and total pika burrow exits were automatically retrieved using the self-developed image processing software. We found that there were significant linear relationships between the vegetation species diversity indexes obtained by these two methods. Additionally, the total number of identified species by the UAV method was 71, which was higher than the Quadrat method recognition, with the quantity of 63. Our results indicate that the UAV was suitable for long-term repeated monitoring vegetation species composition of multiple alpine grasslands at plot scale. With the merits of UAV, it confirmed that pika’s disturbance belonged to the medium level, with the density ranging from 30.17 to 65.53 ha−1. Under this density level, pika had a positive effect on vegetation species diversity, particularly for the species richness of sedge and forb. These findings conclude that the UAV was an efficient and economic tool for species monitoring to reveal the role of pika in the alpine grasslands.

Aerial mark–recapture population estimates utilising the natural markings of wild horses to identify individuals was applied in the Bogong High Plains, Alpine National Park, Victoria. A discrete population of wild horses occupying an area of 180 km2 was sampled over two days in 2005. This study explored the feasibility of a technique that aimed to enable managers to estimate the size of the horse population and monitor it over time. Four observers (including the pilot) searched for horses from a helicopter. Once horses were sighted, photographic and written observations were used to ‘mark’ each animal. The survey was repeated the following day with observations ‘recapturing’ individuals. Data were analysed using several mark–recapture estimators, and the derived population estimates ranged from 89 (±5.3, s.e.) horses to 94.7 (±7.9, s.e.) horses. We found that the method gave a level of precision relevant to management, but needs refinement. The technique and its assumptions should be tested further by increasing the number of samples and video should be used to improve identification of individuals. We believe that this is a novel application for aerial surveys, which are typically unsuitable for estimating the size of small populations. This technique was developed for horses but may be used on other conspicuous species with unique natural markings.

Abstract. The paper considers conditions and intensity of aeolian and dune slope transformation processes occurring in the wind-blown sand strips of the dunes of the Curonian Spit. An assessment of the intensity of aeolian processes was made based on the analysis of climatic factors and in situ observations. Transformations in aeolian relief forms were investigated based on the comparison of geodetic measurements and measurements of aerial photographs. Changes in micro-terraces of dune slopes were investigated through comparison of the results of repeated levelling and measurements of aerial photographs. The periods of weak, medium, and strong winds were distinguished, and sand moisture fluctuations affecting the beginning of aeolian processes were investigated. The wind-blown sand movements were found to start when sand moisture decreased by 2 % in the surface sand layer and by up to 5 % at a depth of 10 cm. In 2004–2016, the wind-blown sand movements affected the size of reference deflation relief forms: scarp length by 8 %, scarp width by 35 %, pothole length by 80 %, pothole width by 80 %, roll length by 17 %, roll width by 18 %, hollow length by 17 %, and hollow width by 39 %. The elementary relief forms in the leeward eastern slopes of the dunes experienced the strongest transformations. During a period of 5 months, the height of micro-terraces of the eastern slope of the Parnidis Dune changed from 0.05 to 0.64 cm. The change was related to fluctuations in precipitation intensity: in July–August 2016 the amount of precipitation increased 1.6-fold compared with the multiannual average, thus causing the change in the position of terrace ledges by 21 %.

Objectives: An Australian access economics report (2009) estimated the lifetime cost of care is 5.0 million for a person whom suffers paraplegia and 9.5 million for quadriplegia, and costs/year are approximately $90,000. Hilton )2018( on drones at sporting venues discusses their potential to revolutionize injury surveillance monitoring via expert exposure gained for recording, investigation, tracking and monitoring of sporting injuries. Hilton (2018) reviewed rugby union and league Australian spinal cord injury datasets, finding more incident cases in the union then league [1]. Methods/Analysis: Wikipedia reports 20 professional rugby union and 26 rugby league playing fields in Australia. The Australian Institute of Health and Welfare document; Australian sports injury hospitalizations 2011–12 report just under 800 head and neck injuries requiring hospitalization related to rugby-related sports “35 neck fractures and 348 head fractures”. Brisbane’s leading drone aerial photography service “Droneworxs” according to previous enquiries by the author charge $650/hour to monitor a sporting event. A crude drone implementation cost estimate, hypothetically is to utilize this device across 46 professional clubs X 52 weeks one hour/week = $1,554,800. A basic hypothetical mathematical cost benefit comparison was performed. Findings: Droneworxs cost divided by healthcare costs/case/year ($90,000) = 17 so if these injuries are prevented then cost equivalence is reached figurately speaking, then cost benefits accrue. Novelty /Improvement: Drones are not overly expensive compared to spinal cord injury costs. The occasional presence of aerial cameras at sporting venues may also deter repeated foul play, in the same way that webcam cameras deter potential thieves.

The terminus position of Shoestring Glacier, Mount St. Helens, has pulsated over the last few centuries, generally following local climate trends, but the pattern of advance and retreat has been strongly modulated by effects of local volcanic activity. In this paper, I discuss the techniques employed to map and survey fluctuations in ice velocity, thickness, and terminus position of Shoestring Glacier. Solutions to major problems in acquiring and interpreting data peculiar to an active volcano are also explained. Results show that this steep mountain glacier responds quickly and dramatically to local environmental changes. The effects of volcanic activity are distinguished from internal instabilities and local climate change by combining information obtained using a variety of techniques, including field surveying, contour-mapping using stereo-aerial photographs, photo-documentation, and published historical accounts, In this paper I will focus attention on surveying and mapping conducted since 1979 at Shoestring Glacier, but will also discuss methods used to identify historic and “prehistoric” glacier fluctuations back to the early 1800s. The field survey was conducted at the glacier from mid-1979 to late 1983, during several eruptive episodes, major earthquakes, and covering winter and summer velocity and thickness changes. (Brugman and Post, 1980; Brugman and Meier, 1981). Coordinates of glacier velocity markers and the survey reference net were monitored with several different theodolites and electronic distance meters. In addition, topographic maps of Shoestring Glacier and vicinity were made for the years between 1979 and 1982, for the purpose of characterizing the drastic changes which occurred during the volcanic eruption of Mount St. Helens of May 18, 1980. The maps were constructed with 2 m contour intervals, using three sets of vertical aerial photographs. The difference between maps results in two plots showing the surficial changes caused by the volcanic field-checked against ground survey data on thickness change, using standard techniques. Overall, this study included monitoring glacier flow, configuration, and thickness changes at Shoestring Glacier since mid-1979, and also monitoring any changes in the local survey net due to ground deformation associated with nearby volcanic activity. In addition, photographic and written documentation of recent glacier fluctuations at Mount St. Helens was compiled from a variety of sources, which included local explorers, scientists, mountaineers, aviators, and historians. From this information, I was able to obtain the general pattern of Shoestring Glacier terminus fluctuations since the early 1900s. To extend the study further back in time, I also mapped the local surficial geology surrounding Shoestring Glacier using aerial photographs and ground studies. Because Mount St. Helens is a highly active, young volcano, a major problem was to distinguish glacier moraines, built during a recent ice advance, from volcanic levees built during passage of a recent lahar. Both lahar levees and glacier moraines exist along the glacier margin and most have been dissected and scoured by later mudflows. This study required the separate identification of glacial lag-till, from mudflow and rock avalanche debris. Comparison of depositional and erosional features generated by the several major lahars which decended over the Shoestring Glacier during the 1980 eruptions to pre-1980 surficial geology shows that glacier and lahar deposits are closely intermingled, but they can be distinguished on the basis of surface morphology obtained from aerial photographs, supported by field mapping of sedimentary structures. The dominant pre-1980 surficial deposits were laid down during a time of intense volcanism dating from 1800-1857, when the Shoestring Glacier was initially at its most advanced terminus position in its limited geologic record. During the early 1900s, several minor historic eruptions deposited ash and debris as distinctive englacial debris layers, which were well preserved within the glaciers on Mount St. Helens. Rock material deposited in the early to mid-1800s from glacier advances and volcanic eruptions can be distinguished from volcanic material deposited during the early 1900s because of the minor effect these later eruptions had on the glaciers of Mount St. Helens. This study shows that, over the last few centuries, repeated eruptions of Mount St. Helens have caused important changes in the mass balance of Shoestring Glacier. During several volcanic eruptions since 1800, the Shoestring and nearby glaciers have been deeply blanketed with rock ejecta and avalanche and mudflow debris, which could have increased the glacier mass balances. In contrast, the dominant effect of major volcanic eruptions on the Shoestring Glacier has led to strongly negative mass balances due to scouring, melting, and blasting away of glacier snow and ice. Deep incision of the glacier and its surrounding topography is clearly evident from the maps produced during this study, both during and before 1980. This melting and scouring occurred as pyroclastic flows and lahars swept down the glacier-filled canyon from the summit of the volcano and has probably occurred repeatedly since the canyon holding the Shoestring Glacier was first cut, approximately two thousand years ago. The eruption of Mount St. Helens on May 18, 1980, when the Shoestring Glacier was beheaded, deeply incised, and covered by volcanic ejecta and mudflow debris, is the most recent example of the highly variable environment in which the glacier continues to survive.

The terminus position of Shoestring Glacier, Mount St. Helens, has pulsated over the last few centuries, generally following local climate trends, but the pattern of advance and retreat has been strongly modulated by effects of local volcanic activity. In this paper, I discuss the techniques employed to map and survey fluctuations in ice velocity, thickness, and terminus position of Shoestring Glacier. Solutions to major problems in acquiring and interpreting data peculiar to an active volcano are also explained. Results show that this steep mountain glacier responds quickly and dramatically to local environmental changes. The effects of volcanic activity are distinguished from internal instabilities and local climate change by combining information obtained using a variety of techniques, including field surveying, contour-mapping using stereo-aerial photographs, photo-documentation, and published historical accounts, In this paper I will focus attention on surveying and mapping conducted since 1979 at Shoestring Glacier, but will also discuss methods used to identify historic and “prehistoric” glacier fluctuations back to the early 1800s.The field survey was conducted at the glacier from mid-1979 to late 1983, during several eruptive episodes, major earthquakes, and covering winter and summer velocity and thickness changes. (Brugman and Post, 1980; Brugman and Meier, 1981). Coordinates of glacier velocity markers and the survey reference net were monitored with several different theodolites and electronic distance meters. In addition, topographic maps of Shoestring Glacier and vicinity were made for the years between 1979 and 1982, for the purpose of characterizing the drastic changes which occurred during the volcanic eruption of Mount St. Helens of May 18, 1980. The maps were constructed with 2 m contour intervals, using three sets of vertical aerial photographs. The difference between maps results in two plots showing the surficial changes caused by the volcanic field-checked against ground survey data on thickness change, using standard techniques. Overall, this study included monitoring glacier flow, configuration, and thickness changes at Shoestring Glacier since mid-1979, and also monitoring any changes in the local survey net due to ground deformation associated with nearby volcanic activity.In addition, photographic and written documentation of recent glacier fluctuations at Mount St. Helens was compiled from a variety of sources, which included local explorers, scientists, mountaineers, aviators, and historians. From this information, I was able to obtain the general pattern of Shoestring Glacier terminus fluctuations since the early 1900s.To extend the study further back in time, I also mapped the local surficial geology surrounding Shoestring Glacier using aerial photographs and ground studies. Because Mount St. Helens is a highly active, young volcano, a major problem was to distinguish glacier moraines, built during a recent ice advance, from volcanic levees built during passage of a recent lahar. Both lahar levees and glacier moraines exist along the glacier margin and most have been dissected and scoured by later mudflows. This study required the separate identification of glacial lag-till, from mudflow and rock avalanche debris. Comparison of depositional and erosional features generated by the several major lahars which decended over the Shoestring Glacier during the 1980 eruptions to pre-1980 surficial geology shows that glacier and lahar deposits are closely intermingled, but they can be distinguished on the basis of surface morphology obtained from aerial photographs, supported by field mapping of sedimentary structures. The dominant pre-1980 surficial deposits were laid down during a time of intense volcanism dating from 1800-1857, when the Shoestring Glacier was initially at its most advanced terminus position in its limited geologic record. During the early 1900s, several minor historic eruptions deposited ash and debris as distinctive englacial debris layers, which were well preserved within the glaciers on Mount St. Helens. Rock material deposited in the early to mid-1800s from glacier advances and volcanic eruptions can be distinguished from volcanic material deposited during the early 1900s because of the minor effect these later eruptions had on the glaciers of Mount St. Helens.This study shows that, over the last few centuries, repeated eruptions of Mount St. Helens have caused important changes in the mass balance of Shoestring Glacier. During several volcanic eruptions since 1800, the Shoestring and nearby glaciers have been deeply blanketed with rock ejecta and avalanche and mudflow debris, which could have increased the glacier mass balances. In contrast, the dominant effect of major volcanic eruptions on the Shoestring Glacier has led to strongly negative mass balances due to scouring, melting, and blasting away of glacier snow and ice. Deep incision of the glacier and its surrounding topography is clearly evident from the maps produced during this study, both during and before 1980. This melting and scouring occurred as pyroclastic flows and lahars swept down the glacier-filled canyon from the summit of the volcano and has probably occurred repeatedly since the canyon holding the Shoestring Glacier was first cut, approximately two thousand years ago. The eruption of Mount St. Helens on May 18, 1980, when the Shoestring Glacier was beheaded, deeply incised, and covered by volcanic ejecta and mudflow debris, is the most recent example of the highly variable environment in which the glacier continues to survive.

ABSTRACTDonjek Glacier has an unusually short and regular surge cycle, with eight surges identified since 1935 from aerial photographs and satellite imagery with a ~12 year repeat interval and ~2 year active phase. Recent surges occurred during a period of long-term negative mass balance and cumulative terminus retreat of 2.5 km since 1874. In contrast to previous work, we find that the constriction where the valley narrows and bedrock lithology changes, 21 km from the terminus, represents the upper limit of surging, with negligible surface speed or elevation change up-glacier from this location. This positions the entire surge-type portion of the glacier in the ablation zone. The constriction geometry does not act as the dynamic balance line, which we consistently find at 8 km from the glacier terminus. During the 2012–2014 surge event, the average lowering rate in the lowest 21 km of the glacier was 9.6 m a−1, while during quiescence it was 1.0 m a−1. Due to reservoir zone refilling, the ablation zone has a positive geodetic balance in years immediately following a surge event. An active surge phase can result in a strongly negative geodetic mass balance over the surge-type portion of the glacier.

Abstract. Monitoring agricultural areas threatened by soil erosion often requires decimetre topographic information over areas of several square kilometres. Airborne lidar and remotely piloted aircraft system (RPAS) imagery have the ability to provide repeated decimetre-resolution and -accuracy digital elevation models (DEMs) covering these extents, which is unrealistic with ground surveys. However, various factors hamper the dissemination of these technologies in a wide range of situations, including local regulations for RPAS and the cost for airborne laser systems and medium-format RPAS imagery. The goal of this study is to investigate the ability of low-tech kite aerial photography to obtain DEMs with decimetre resolution and accuracy that permit 3-D descriptions of active gullying in cultivated areas of several square kilometres. To this end, we developed and assessed a two-step workflow. First, we used both heuristic experimental approaches in field and numerical simulations to determine the conditions that make a photogrammetric flight possible and effective over several square kilometres with a kite and a consumer-grade camera. Second, we mapped and characterised the entire gully system of a test catchment in 3-D. We showed numerically and experimentally that using a thin and light line for the kite is key for a complete 3-D coverage over several square kilometres. We thus obtained a decimetre-resolution DEM covering 3.18 km2 with a mean error and standard deviation of the error of +7 and 22 cm respectively, hence achieving decimetre accuracy. With this data set, we showed that high-resolution topographic data permit both the detection and characterisation of an entire gully system with a high level of detail and an overall accuracy of 74 % compared to an independent field survey. Kite aerial photography with simple but appropriate equipment is hence an alternative tool that has been proven to be valuable for surveying gullies with sub-metric details in a square-kilometre-scale catchment. This case study suggests that access to high-resolution topographic data on these scales can be given to the community, which may help facilitate a better understanding of gullying processes within a broader spectrum of conditions.

In the Pacific Northwest, the process of conifer development after stand-replacing disturbance has important implications for many forest processes (e.g., carbon storage, nutrient cycling, and biodiversity). This paper examines conifer development in the Coast Range Province and Western Cascades Province of Oregon using repeat interpretation of historic aerial photographs from 1959 to 1997 to examine the canopy cover change of different life forms: shrubs, hardwood trees, and conifer trees. Ninety-four stands from the Western Cascades Province and 59 stands from the Coast Range Province were photointerpreted in roughly 5-year intervals. A Chapman–Richards growth function was used to model conifer cover development for all sample stands. Based on the photo data and the Chapman–Richards function, these stands were classified into one of seven early forest successional trajectories defined by the vegetation physiognomy. Succession in the Coast Range Province and Western Cascades Province were compared using parameters derived from the Chapman–Richards growth function. Our results echo previous studies in that rates and densities of conifer regeneration varied markedly among sites; however, our results also indicate that early forest succession differs in the two study regions in terms of both trajectories and rates. Conifer regeneration in the Western Cascades Province tends to have longer delays in establishing and slower rates compared with the Coast Range Province.

All known forecasting methods cannot do without the help of maps when it comes to natural phenomena and processes. Geographic forecasting can be considered as predicting geographic phenomena or processes that cannot be explored. Identity of the methodology for forecasting the dynamics of phenomena in time and their propagation in space makes it possible to transfer the patterns that are true for time sequences to spatial series. In contrast to specialized forecasting methods developed by individual sciences, cartography provides a researcher with a general forecasting method called cartographic extrapolation. In this case the extrapolation is understood as the spread of patterns obtained in the course of cartographic analysis of a phenomenon or a process to an unexplored part of this phenomenon or process to another territory, for the future. The foregoing is considered on the example of a map of Modern vertical movements of the Earth’s crust in the Republic of Belarus which is compiled according to geophysical data and repeated leveling. Predictive patterns and expectations are highlighted while applying the method of cartographic extrapolation on the map. The efficiency of cartographic extrapolation is increased with the complex use of different methods. The interaction of cartographic and remote methods is of particular importance. Joint analysis of maps, aerial and satellite images obtained from different heights and in different ranges helps to predict general global, regional or local patterns. An example of this is geological and geomorphological research. Maps of different contents and the results of interpretation of aerial photographs have been used to predict the neo-tectonic structure of the territory in the zone of junction of the Mikashevich ledge of the crystalline basement and the Turov depression in the Belarusian Polesie.

Ecological exposition as one of the types of landscape exposition, shows plants of certain ecological groups. As a rule, conditions are created for such plants that simulate their natural habitat. At the same time, changing the existing environmental conditions is resource-intensive, and the result obtained cannot fully repeat the natural conditions due to their multicomponent nature and being confined to a certain climatic zone. It is of interest to use the existing natural and anthropogenic conditions for the arrangement of expositions, without changing them, but using the existing resource. The authors highlight the problem of using the coastal territory along the ponds on the Kamenka River of the Main Botanical Garden named after N.V. Tsitsin of the Russian Academy of Sciences (MBG RAS). The paper defines the potential of the territory for creating ecological expositions along the shoreline of the Kamensky Ponds of the Russian Academy of Sciences, using the existing natural conditions. In the course of research, a comprehensive approach to the analysis of natural conditions and historical facts is applied. For the historical analysis, the method of combining planned materials and decoding aerial photographs was used. To describe the environmental factors, a landscape-visual survey of the territory, a combination of satellite images with modern maps, an inventory of green spaces, soil mapping, and an inventory of green spaces were performed. As a result of the research, 10 zones with different environmental conditions were identified. Since the formation of the MBG RAS in 1945, the study area has been allocated to different expositions and zones (Entrance Group, Garden of Coastal Plants and part of the Garden of Continuous Flowering), which over time have completely or partially lost their relevance or decorativeness.

Texture strongly influences the soil’s fundamental functions in forest ecosystems. In response to the growing demand for information on soil properties for environmental modeling, more and more studies have been conducted over the past decade to assess the spatial variability of soil properties on a regional to global scale. These investigations rely on the acquisition and compilation of numerous soil field records and on the development of statistical methods and technology. Here, we used random forest machine learning algorithms to model and map particle size composition in ecoforest polygons for the entire area of managed forests in the province of Quebec, Canada. We compiled archived laboratory analyses of 29,570 mineral soil samples (17,901 sites) and a set of 33 covariates, including 22 variables related to climate, five related to soil characteristics, three to spatial position or spatial context, two to relief and topography, and one to vegetation. After five repeats of 5-fold cross-validation, results show that models that include two functionally independent values regarding particle size composition explain 60%, 34%, and 78% of the variance in sand, silt and clay fractions, respectively, with mean absolute errors ranging from 4.0% for the clay fraction to 9.5% for the sand fraction. The most important model variables are those observed in the field and those interpreted from aerial photography regarding soil characteristics, followed by those regarding elevation and climate. Our results compare favorably with those of previous soil texture mapping studies for the same territory, in which particle size composition was modeled mainly from rasterized climatic and topographic covariates. The map we provide should meet the needs of provincial forest managers, as it is compatible with the ecoforest map that constitutes the basis of information for forest management in Quebec, Canada.

The UK holds approximately 40% of the European harbour seal population, with the majority found around the coasts of Scotland. Harbour seal populations in the UK have been monitored through a series of repeated aerial surveys of animals hauled out during the annual moult in early August. This moult count is used as a consistent index of population size. Survey methods and frequencies vary. The Scottish and English east coast populations mainly haul out in tidal estuariesand are surveyed annually, using fixed wing aircraft and digital photography. Populations in north and west Scotland often haul out on rocky shores and are surveyed less frequently, using helicopters fitted with thermal imagers. Overall, the most recent minimum estimate of the UK harbour seal population is 24,250 seals of which 19,800 are in Scotland, 3,200 in England and 1,250 in Northern Ireland. The results show that the number of harbour seals in eastern Englandwas increasing before the 1988 and 2002 phocine distemper (PDV) epizootic but has not increased since the end of the 2002 epizootic. There is also evidence of a general decline in most of the large harbour seal colonies around Scotland. The populations along the north and northwest mainland coast were an exception, with numbers appearing to be stable. Between 2001 and 2008, the population in Orkney declined by 67% and Shetland declined by 40%, indicating harbourseals in these areas experienced substantially increased mortality or very low recruitment over this period. The widespread declines, ranging from Shetland to The Wash, suggest that the causes may have been present over a large part of the North Sea and waters off western Scotland.

In ecosystems where fire occurrence has significant time-dependence, fire sequences should exhibit system-regulation that is distinguished by nonrandom (nonstationary), self-organizing patch dynamics related to spatially constrained fire probabilities. Exogenous factors such as fire weather, precipitation variability, and terrain alter the flammability of vegetation and encourage randomness in fire occurrence within pre-existing patch structure. In Californian chaparral, the roles of succession/fuel build-up and exogenous factors is examined by taking advantage of a 100 yr 'natural experiment' in southern California (SCA) and northern Baja California, Mexico (BCA), where factors influencing fire occurrence have been systematically altered by divergent management systems. In SCA, suppression has been practiced since 1900. In BCA, fire control was not official policy until the 1960s and has not been effectively practiced. Fire perimeter histories for 1920-1971 in SCA and BCA, reconstructed from fire history records and repeat aerial photographs, are compared for fire frequency (events/area), size, rotation periods, stand age structure, ignition rates, weather, burning season, and drought. Landscape-scale fire rotation periods are long (≈70 yr) regardless of management policies because fire occurrence is driven by the gradual development of fire hazard during succession, produced by small annual increments of growth and litterfall, as well as by high fuel moisture in evergreen shrubs. Without fire control frequent fires establish fine-grained mosaics. Fire control reduces fire frequencies, increases fire size, and encourages coarse-scale patch structure. Patch dynamics exhibit evidences of nonrandom turnover. Fire size distributions reflect the nearest-neighbor distances between patches below some age-dependent combustion threshold (CT) in the patch mosaic that resist the spread of fires in stands older than CT. Regional burn rates are poorly related to fire frequency, ignition rates, drought, and terrain. The small size of fires in BCA may be reinforced by interactions between fire and pre-existing, fine-grained patch structure, and by random fire occurrence in the probability distributions of fire weather and climate. In SCA, fires are nonrandomly restricted by fire control to extreme weather.

AbstractAldegondabreen is a small valley glacier, ending on land, located in the Grønfjorden area of Spitsbergen, Svalbard. Airborne radio-echo sounding in 1974/75, using a 440 MHz radar, revealed a polythermal two-layered structure, which has been confirmed by detailed ground-based radio-echo sounding done in 1999 using a 15 MHz monopulse radar. The 1999 radar data reveal an upper cold layer extending down to 90m depth in the southern part of the glacier, where the thickest ice (216 m) was also found. A repeated pattern of diffractions from the southern part of the glacier, at depths of 50–80 m and dipping down-glacier, has been interpreted as an englacial channel which originates in the temperate ice. From joint analysis of the 1936 topographic map, a digital elevation model constructed from 1990 aerial photographs and the subglacial topography determined from radar data, a severe loss of mass during the period 1936–90 has been estimated: a glacier tongue retreat of 930 m, a decrease in area from 8.9 to 7.6 km2, in average ice thickness from 101 to 73 m and in ice volume from 0.950 to 0.558 km3, which are equivalent to an average annual balance of –0.7 mw.e. This is comparable with the only available data of net mass balance for Aldegondabreen (–1.1 and –1.35m w.e. for the balance years 1976/77 and 2002/03) and consistent with the 0.27˚C increase in mean summer air temperature in this zone during 1936–90, as well as the warming in Spitsbergen following the end of the Little Ice Age (LIA), and the general glacier recession trend observed in this region.

<p><strong>Abstract.</strong> Assessment and monitoring of environmental features based on large-scale and ultra-high resolution data, including remote sensing data, which have advantages in the repeatability of information and the speed of processing of incoming data, often face issues of completeness and duration of time series in retrospective analysis. Cartographic materials and remote sensing data allow monitoring for rapidly changing natural and anthropogenic features in the study areas, but very often face a problem when an event or phenomenon occurred many years ago and it is necessary to make a complete chronology.</p><p>Ultra-high-resolution data, remote sensing data and the results of the subsequent geoinformation analysis are widely used to solve problems in a number of socio-economic areas of territorial development, in particular:</p><ul><li>in environmental studies &amp;ndash; identification of local sources of water pollution, the consequences of their impact onecosystems, synthetic assessment of the ecological state of the territories and their comfort;</li><li>in the management of various resources, including water &amp;ndash; determination of biological productivity of water bodies, identification of water bioresources, detection of anthropogenically provoked and natural changes in water mass,implementation for glaciological studies, etc.</li></ul><p>Within the framework of the current study, a multi-time analysis of the water area and the coastal strip of Lake Sevan (the Republic of Armenia) at an altitude of about 1900 m above sea level, was carried out. The lake has repeatedly beensubjected to changes in the water level of the reservoir in the past. The 1930s and in the period between 1949 to 1962 were noted by the most intense drop in water level (more than 10 meters). In the 1990s, there was a slight increase inthe level, and then until 2001, the level of the lake continued to decrease.</p><p>The main factors affecting aquatic ecosystems and the overall ecological status of the lake are:</p><ol><li>Repeated changes in the water level of the reservoir in the past and its expected fluctuations in the future.</li><li>The uncontrolled discharge of harmful substances caused great damage to the lake, which affected the water qualityand biodiversity of this unique natural site.</li><li>Untimely cleaning of flooded forests, which increases the risk of eutrophication of the lake.</li><li>The poorly organized system of waste disposal and unauthorized landfills of municipal solid waste, as well as animalwaste.</li><li>Unauthorized construction of recreational facilities and capital structures in the coastal and water protection zonewhich may be flooded.</li></ol><p> The information support of the study is based on the materials of satellite imagery from the worldview2, SPOT 5/6,Resurs-P, Canopus-B, materials from the international space station (ISS), materials of archival aerial photography anddata obtained from the UAVs, in combination with other map data sources in the range of scales 1&amp;thinsp;:&amp;thinsp;5&amp;thinsp;000 &amp;ndash; 1&amp;thinsp;:&amp;thinsp;100&amp;thinsp;000,including digital topographic maps, land use maps, statistical and literary data. In fact, cartographic materials andremote sensing data provide a time history of 75 years, from large-scale topographic maps of 1942&amp;ndash;1943 to highlydetailed images of 2017&amp;ndash;2018.</p><p>According to the results of the study, it was possible to establish the position of the coastline for different time periods.The period between 1949 and 1962, when there was the most critical drop in the water level, was especially interestingand had not been studied before. Archival aerial photographs for 1943 and 1963 allowed to reconstruct the position ofthe coastline for almost every year of irrational water use.</p>

Remote-sensing methods in monitoring the glacierization of Mount EI‛ brus are used to produce base and dynamic maps, and to obtain quantitative information (dynamic indices) about the rate, intensity, and variations of the process. The monitoring system is divided, according to scope and territory covered, into small-scale for total glacierization and the periglacial zone, medium-scale for separate glaciers, and large-scale (detailed) for part of the glaciers or sectors of the adjoining slopes. The approximate relationship of even scales is 1 : 4. Small-scale monitoring remote-sensing systems are important for making maps showing the complex characteristics of the glaciological system. A series of maps was produced including geographical, those of high-altitude zones, slope and exposure angles, geological, glaciomorphological, climatic (temperature, precipitation, and winds), distribution of direct solar radiation, hydrological (source of streams), seats of avalanches, and landslides. All these data serve as a cartographical basis in monitoring the glacierization of Mount EI‛ brus. They are compiled from remotely sensed and Earth-based data. Current monitoring on a small scale includes observations of the conditions which determine the existence of the glacial system - this includes data on winter snowfall and the period of snow cover. These observations were obtained from meteorological and resource satellites, and from scanner data of medium and high resolution. Also important are observations of changes in the outline of glaciers, times of snowfall and character of the distribution of snow, and its redistribution due to avalanches and snowstorms. High-resolution space photographs, small-scale aerial photographs, and aerovisual observations provide the data for these observations. It has been determined that the area of the glaciers of Mount El‛ brus has been reduced by 1 % in the last 25 years, i.e. the rate of its deglacierization dropped sharply as compared to preceding decades. The role of quantitative information gains importance in the medium-scale level of monitoring. Topographical maps of separate glaciers compiled from aerial photographs or data from ground stereo-photogrammetric surveys constitute the base maps at this level. The main method used in monitoring were large-scale surveys from aircraft, perspective surveys from helicopters, and phototheodolite surveys. Multi-date surveys of the glaciers provide data about the changes in their outlines and height, the character of their relief, their moraines, the amount of snow accumulation and ablation in separate years, the surface rates of ice flow and their fluctuations. The techniques by which quantitative information is obtained about changes in the glaciers are derived from processing the data of multi-date surveys. The organization and techniques of phototheodolite surveys have been improved. A theory evolved for determining the surface-ice movement by stereo-photogrammetric means and the technique for it has also improved; algorithms and programs for machine processing of the data of multi-date surveys (ground and from aircraft) have been produced At this level of monitoring, it has been found that the retreat rate of most glaciers has slowed down and several glaciers are now in equilibrium. Several glaciers became active at the beginning of the 1970s and 1980s; this was accompanied by an increase in their height and forward movement. For example, activation of Kyukyurtlyu Glacier has been recorded (higher surface and increasing flow rate) which has caused the glacier to move forward 100 m. Surveys at an interval of 2 years recorded the beginning of the process of retreat of this glacier. Detailed monitoring is used to detect the mechanism of the dynamic processes and to study it on local representative sectors. On a glacier it may take the form of annual surveys of its tongue, which makes it possible to observe the processes of formation of moraines and glacio-fluvial relief. Studies may also be made of the mechanism of the movement of avalanches and landslides, deducing their quantitative characteristics and appraising the results of avalanches and landslides. Multi-date surveys of sectors of the slopes provide information about processes in the periglacial zone. At this level, regularly repeated ground stereo-photogrammetric surveys are the main means of observation. Glaciological remote-sensing monitoring provides a wealth of data for theoretical development in the field of glaciology. It makes it possible to forecast and produce warnings about hazardous processes and phenomena.

Remote-sensing methods in monitoring the glacierization of Mount EI‛ brus are used to produce base and dynamic maps, and to obtain quantitative information (dynamic indices) about the rate, intensity, and variations of the process. The monitoring system is divided, according to scope and territory covered, into small-scale for total glacierization and the periglacial zone, medium-scale for separate glaciers, and large-scale (detailed) for part of the glaciers or sectors of the adjoining slopes. The approximate relationship of even scales is 1 : 4.Small-scale monitoring remote-sensing systems are important for making maps showing the complex characteristics of the glaciological system. A series of maps was produced including geographical, those of high-altitude zones, slope and exposure angles, geological, glaciomorphological, climatic (temperature, precipitation, and winds), distribution of direct solar radiation, hydrological (source of streams), seats of avalanches, and landslides. All these data serve as a cartographical basis in monitoring the glacierization of Mount EI‛ brus. They are compiled from remotely sensed and Earth-based data.Current monitoring on a small scale includes observations of the conditions which determine the existence of the glacial system - this includes data on winter snowfall and the period of snow cover. These observations were obtained from meteorological and resource satellites, and from scanner data of medium and high resolution. Also important are observations of changes in the outline of glaciers, times of snowfall and character of the distribution of snow, and its redistribution due to avalanches and snowstorms. High-resolution space photographs, small-scale aerial photographs, and aerovisual observations provide the data for these observations. It has been determined that the area of the glaciers of Mount El‛ brus has been reduced by 1 % in the last 25 years, i.e. the rate of its deglacierization dropped sharply as compared to preceding decades.The role of quantitative information gains importance in the medium-scale level of monitoring. Topographical maps of separate glaciers compiled from aerial photographs or data from ground stereo-photogrammetric surveys constitute the base maps at this level. The main method used in monitoring were large-scale surveys from aircraft, perspective surveys from helicopters, and phototheodolite surveys. Multi-date surveys of the glaciers provide data about the changes in their outlines and height, the character of their relief, their moraines, the amount of snow accumulation and ablation in separate years, the surface rates of ice flow and their fluctuations. The techniques by which quantitative information is obtained about changes in the glaciers are derived from processing the data of multi-date surveys. The organization and techniques of phototheodolite surveys have been improved. A theory evolved for determining the surface-ice movement by stereo-photogrammetric means and the technique for it has also improved; algorithms and programs for machine processing of the data of multi-date surveys (ground and from aircraft) have been producedAt this level of monitoring, it has been found that the retreat rate of most glaciers has slowed down and several glaciers are now in equilibrium. Several glaciers became active at the beginning of the 1970s and 1980s; this was accompanied by an increase in their height and forward movement. For example, activation of Kyukyurtlyu Glacier has been recorded (higher surface and increasing flow rate) which has caused the glacier to move forward 100 m. Surveys at an interval of 2 years recorded the beginning of the process of retreat of this glacier.Detailed monitoring is used to detect the mechanism of the dynamic processes and to study it on local representative sectors. On a glacier it may take the form of annual surveys of its tongue, which makes it possible to observe the processes of formation of moraines and glacio-fluvial relief. Studies may also be made of the mechanism of the movement of avalanches and landslides, deducing their quantitative characteristics and appraising the results of avalanches and landslides. Multi-date surveys of sectors of the slopes provide information about processes in the periglacial zone. At this level, regularly repeated ground stereo-photogrammetric surveys are the main means of observation.Glaciological remote-sensing monitoring provides a wealth of data for theoretical development in the field of glaciology. It makes it possible to forecast and produce warnings about hazardous processes and phenomena.

Sediment generation and vegetation recovery was measured over a 2-year post-harvest period in a 36-ha catchment of exotic forest located in andesitic terrain, Whangapoua Forest (36.46°S, 175.36°E), Coromandel, New Zealand. Slopewash, soil scraping (on-slope removal of the regolith by the repeated dragging of logs), and storm-initiated landsliding were identified as the principal sediment-generating processes. Slopewash and vegetation recovery rates were measured using field-based plots located on sites of shallow- and deep-disturbance and a regression relationship was established between sedimentation rate (accumulation (g)/day.mm rain.m2) and per cent vegetation cover for both plot types. At the basin scale, slopewash was calculated using the plot-based rates times the total area of deep- and shallow-disturbance sites as identified from a ground-based, transect survey and using sequential aerial photography. Sediment production, by soil scraping and landsliding, was determined by multiplying mean scar depth by the total affected area. In the first post-harvest year deep-disturbance sites generated 92% of total slopewash produced from both disturbance classes combined, and in year 2, slopewash halved. Half of the first post-harvest year’s slopewash-derived sediment was generated within the first 7 months following the completion of harvesting and before the application of desiccant. Thereafter, on deep-disturbance sites, slopewash rates declined further as sites became hardened against the generation of new sediment (i.e. sites became sediment limited). In contrast, during both the initial post-harvest recovery period and the post-desiccation period, the decline in sediment production on shallow-disturbance sites was more a consequence of site recolonisation. Sediment generated and redistributed by scalping and by landsliding occurred at the time of the respective events and coincided with the early part of the first post-harvest year. Collectively, soil scraping, slopewash, and landslides generated 1864 t (52 t/ha) of sediment, 88% of which remained on-slope. Of the sediment delivered to streams (228 t), landslides contributed 72%, soil scraping 26%, and slopewash 2%. For this harvested basin a single, storm-initiated, landsliding event was the most important hillslope process responsible for the generation of sediment and its delivery to streams, and slopewash was the least important.

In a complex background, insulator fault is the main factor behind transmission accidents. With the wide application of unmanned aerial vehicle (UAV) photography, digital image recognition technology has been further developed to detect the position and fault of insulators. There are two mainstream methods based on deep learning: the first is the “two-stage” example for a region convolutional neural network and the second is the “one-stage” example such as a single-shot multibox detector (SSD), both of which pose many difficulties and challenges. However, due to the complex background and various types of insulators, few researchers apply the “two-stage” method for the detection of insulator faults in aerial images. Moreover, the detection performance of “one-stage” methods is poor for small targets because of the smaller scope of vision and lower accuracy in target detection. In this article, the authors propose an accurate and real-time method for small object detection, an example for insulator location, and its fault inspection based on a mixed- grouped fire single-shot multibox detector (MGFSSD). Based on SSD and deconvolutional single-shot detector (DSSD) networks, the MGFSSD algorithm solves the problems of inaccurate recognition in small objects of the SSD and complex structure and long running time of the DSSD. To resolve the problems of some target repeated detection and small-target missing detection of the original SSD, the authors describe how to design an effective and lightweight feature fusion module to improve the performance of traditional SSDs so that the classifier network can take full advantage of the relationship between the pyramid layer features without changing the base network closest to the input data. The data processing results show that the method can effectively detect insulator faults. The average detection accuracy of insulator faults is 92.4% and the average recall rate is 91.2%.

Abstract The 2011 Tohoku-Oki offshore subduction earthquake (Mw 9.0) triggered many normal-type earthquakes inland in northeastern Japan. Among these were two very similar normal-faulting earthquakes in 2011 (Mw 5.8) and 2016 (Mw 5.9), which created surface ruptures along the newly named Mochiyama fault within the southern Abukuma Mountains, northeastern Japan, where no active faults had been previously mapped by interpretation of aerial photographs. We conducted field surveys in this area immediately after both earthquakes, and we performed trench excavations and observations of fault fracture zones after the 2016 event. These activities were complemented by an interferometric synthetic aperture radar analysis that mapped the areas of deformation and locations of surface discontinuities for both events. The combined results document the coseismic behavior of the Mochiyama fault during both events. Subtle tectonic geomorphic features associated with the fault were evident in a lidar digital elevation model of the area, and layered structures of gouge were documented in the field. These lines of evidence indicate repeated activity at shallow crustal levels and the possibility of Quaternary activity. In addition, our trench excavations revealed at least one faulting event before 2011. Our comparison of paleoseismic records on this and two other normal faults in the Abukuma Mountains suggests that great earthquakes in the Japan Trench supercycle of 500–700 years do not consistently trigger ruptures on these faults, and the case of 2011, in which the Tohoku-Oki megathrust earthquake triggered all three faults, is a rare occurrence.

The research data repository of the Environmental Data Initiative (EDI) is building on over 30 years of data curation research and experience in the National Science Foundation-funded US Long-Term Ecological Research (LTER) Network. It provides mature functionalities, well established workflows, and now publishes all ‘long-tail’ environmental data. High quality scientific metadata are enforced through automatic checks against community developed rules and the Ecological Metadata Language (EML) standard. Although the EDI repository is far along in making its data findable, accessible, interoperable, and reusable (FAIR), representatives from EDI and the LTER are developing best practices for the edge cases in environmental data publishing. One of these is the vast amount of imagery taken in the context of ecological research, ranging from wildlife camera traps to plankton imaging systems to aerial photography. Many images are used in biodiversity research for community analyses (e.g., individual counts, species cover, biovolume, productivity), while others are taken to study animal behavior and landscape-level change. Some examples from the LTER Network include: using photos of a heron colony to measure provisioning rates for chicks (Clarkson and Erwin 2018) or identifying changes in plant cover and functional type through time (Peters et al. 2020). Multi-spectral images are employed to identify prairie species. Underwater photo quads are used to monitor changes in benthic biodiversity (Edmunds 2015). Sosik et al. (2020) used a continuous Imaging FlowCytobot to identify and measure phyto- and microzooplankton. Cameras at McMurdo Dry Valleys assess snow and ice cover on Antarctic lakes allowing estimation of primary production (Myers 2019). It has been standard practice to publish numerical data extracted from images in EDI; however, the supporting imagery generally has not been made publicly available. Our goal in developing best practices for documenting and archiving these images is for them to be discovered and re-used. Our examples demonstrate several issues. The research questions, and hence, the image subjects are variable. Images frequently come in logical sets of time series. The size of such sets can be large and only some images may be contributed to a dedicated specialized repository. Finally, these images are taken in a larger monitoring context where many other environmental data are collected at the same time and location. Currently, a typical approach to publishing image data in EDI are packages containing compressed (ZIP or tar) files with the images, a directory manifest with additional image-specific metadata, and a package-level EML metadata file. Images in the compressed archive may be organized within directories with filenames corresponding to treatments, locations, time periods, individuals, or other grouping attributes. Additionally, the directory manifest table has columns for each attribute. Package-level metadata include standard coverage elements (e.g., date, time, location) and sampling methods. This approach of archiving logical ‘sets’ of images reduces the effort of providing metadata for each image when most information would be repeated, but at the expense of not making every image individually searchable. The latter may be overcome if the provided manifest contains standard metadata that would allow searching and automatic integration with other images.

Special Care Notice This article contains images of deceased people that might cause sadness or distress to Aboriginal and Torres Strait Islander readers. Introduction Like many cities, Perth was founded on wetlands that have been integral to its history and culture (Seddon 226–32). However, in order to promote a settlement agenda, early mapmakers sought to erase the city’s wetlands from cartographic depictions (Giblett, Cities). Since the colonial era, inner-Perth’s swamps and lakes have been drained, filled, significantly reduced in size, or otherwise reclaimed for urban expansion (Bekle). Not only have the swamps and lakes physically disappeared, the memories of their presence and influence on the city’s development over time are also largely forgotten. What was the site of Perth, specifically its wetlands, like before British settlement? In 2014, an interdisciplinary team at Edith Cowan University developed a digital visualisation process to re-imagine Perth prior to colonisation. This was based on early maps of the Swan River Colony and a range of archival information. The images depicted the city’s topography, hydrology, and vegetation and became the centerpiece of a physical exhibition entitled Re-imagining Perth’s Lost Wetlands and a virtual exhibition hosted by the Western Australian Museum. Alongside historic maps, paintings, photographs, and writings, the visual reconstruction of Perth aimed to foster appreciation of the pre-settlement environment—the homeland of the Whadjuck Nyoongar, or Bibbulmun, people (Carter and Nutter). The exhibition included the narrative of Fanny Balbuk, a Nyoongar woman who voiced her indignation over the “usurping of her beloved home ground” (Bates, The Passing 69) by flouting property lines and walking through private residences to reach places of cultural significance. Beginning with Balbuk’s story and the digital tracing of her walking route through colonial Perth, this article discusses the project in the context of contemporary pressures on the city’s extant wetlands. The re-imagining of Perth through historically, culturally, and geographically-grounded digital visualisation approaches can inspire the conservation of its wetlands heritage. Balbuk’s Walk through the City For many who grew up in Perth, Fanny Balbuk’s perambulations have achieved legendary status in the collective cultural imagination. In his memoir, David Whish-Wilson mentions Balbuk’s defiant walks and the lighting up of the city for astronaut John Glenn in 1962 as the two stories that had the most impact on his Perth childhood. From Gordon Stephenson House, Whish-Wilson visualises her journey in his mind’s eye, past Government House on St Georges Terrace (the main thoroughfare through the city centre), then north on Barrack Street towards the railway station, the site of Lake Kingsford where Balbuk once gathered bush tucker (4). He considers the footpaths “beneath the geometric frame of the modern city […] worn smooth over millennia that snake up through the sheoak and marri woodland and into the city’s heart” (Whish-Wilson 4). Balbuk’s story embodies the intertwined culture and nature of Perth—a city of wetlands. Born in 1840 on Heirisson Island, Balbuk (also known as Yooreel) (Figure 1) had ancestral bonds to the urban landscape. According to Daisy Bates, writing in the early 1900s, the Nyoongar term Matagarup, or “leg deep,” denotes the passage of shallow water near Heirisson Island where Balbuk would have forded the Swan River (“Oldest” 16). Yoonderup was recorded as the Nyoongar name for Heirisson Island (Bates, “Oldest” 16) and the birthplace of Balbuk’s mother (Bates, “Aboriginal”). In the suburb of Shenton Park near present-day Lake Jualbup, her father bequeathed to her a red ochre (or wilgi) pit that she guarded fervently throughout her life (Bates, “Aboriginal”).Figure 1. Group of Aboriginal Women at Perth, including Fanny Balbuk (far right) (c. 1900). Image Credit: State Library of Western Australia (Image Number: 44c). Balbuk’s grandparents were culturally linked to the site. At his favourite camp beside the freshwater spring near Kings Park on Mounts Bay Road, her grandfather witnessed the arrival of Lieutenant-Colonel Frederick Irwin, cousin of James Stirling (Bates, “Fanny”). In 1879, colonial entrepreneurs established the Swan Brewery at this significant locale (Welborn). Her grandmother’s gravesite later became Government House (Bates, “Fanny”) and she protested vociferously outside “the stone gates guarded by a sentry [that] enclosed her grandmother’s burial ground” (Bates, The Passing 70). Balbuk’s other grandmother was buried beneath Bishop’s Grove, the residence of the city’s first archibishop, now Terrace Hotel (Bates, “Aboriginal”). Historian Bob Reece observes that Balbuk was “the last full-descent woman of Kar’gatta (Karrakatta), the Bibbulmun name for the Mount Eliza [Kings Park] area of Perth” (134). According to accounts drawn from Bates, her home ground traversed the area between Heirisson Island and Perth’s north-western limits. In Kings Park, one of her relatives was buried near a large, hollow tree used by Nyoongar people like a cistern to capture water and which later became the site of the Queen Victoria Statue (Bates, “Aboriginal”). On the slopes of Mount Eliza, the highest point of Kings Park, at the western end of St Georges Terrace, she harvested plant foods, including zamia fruits (Macrozamia riedlei) (Bates, “Fanny”). Fanny Balbuk’s knowledge contributed to the native title claim lodged by Nyoongar people in 2006 as Bennell v. State of Western Australia—the first of its kind to acknowledge Aboriginal land rights in a capital city and part of the larger Single Nyoongar Claim (South West Aboriginal Land and Sea Council et al.). Perth’s colonial administration perceived the city’s wetlands as impediments to progress and as insalubrious environments to be eradicated through reclamation practices. For Balbuk and other Nyoongar people, however, wetlands were “nourishing terrains” (Rose) that afforded sustenance seasonally and meaning perpetually (O’Connor, Quartermaine, and Bodney). Mary Graham, a Kombu-merri elder from Queensland, articulates the connection between land and culture, “because land is sacred and must be looked after, the relation between people and land becomes the template for society and social relations. Therefore all meaning comes from land.” Traditional, embodied reliance on Perth’s wetlands is evident in Bates’ documentation. For instance, Boojoormeup was a “big swamp full of all kinds of food, now turned into Palmerston and Lake streets” (Bates, “Aboriginal”). Considering her cultural values, Balbuk’s determination to maintain pathways through the increasingly colonial Perth environment is unsurprising (Figure 2). From Heirisson Island: a straight track had led to the place where once she had gathered jilgies [crayfish] and vegetable food with the women, in the swamp where Perth railway station now stands. Through fences and over them, Balbuk took the straight track to the end. When a house was built in the way, she broke its fence-palings with her digging stick and charged up the steps and through the rooms. (Bates, The Passing 70) One obstacle was Hooper’s Fence, which Balbuk broke repeatedly on her trips to areas between Kings Park and the railway station (Bates, “Hooper’s”). Her tenacious commitment to walking ancestral routes signifies the friction between settlement infrastructure and traditional Nyoongar livelihood during an era of rapid change. Figure 2. Determination of Fanny Balbuk’s Journey between Yoonderup (Heirisson Island) and Lake Kingsford, traversing what is now the central business district of Perth on the Swan River (2014). Image background prepared by Dimitri Fotev. Track interpolation by Jeff Murray. Project Background and Approach Inspired by Fanny Balbuk’s story, Re-imagining Perth’s Lost Wetlands began as an Australian response to the Mannahatta Project. Founded in 1999, that project used spatial analysis techniques and mapping software to visualise New York’s urbanised Manhattan Island—or Mannahatta as it was called by indigenous people—in the early 1600s (Sanderson). Based on research into the island’s original biogeography and the ecological practices of Native Americans, Mannahatta enabled the public to “peel back” the city’s strata, revealing the original composition of the New York site. The layers of visuals included rich details about the island’s landforms, water systems, and vegetation. Mannahatta compelled Rod Giblett, a cultural researcher at Edith Cowan University, to develop an analogous model for visualising Perth circa 1829. The idea attracted support from the City of Perth, Landgate, and the University. Using stories, artefacts, and maps, the team—comprising a cartographer, designer, three-dimensional modelling expert, and historical researchers—set out to generate visualisations of the landscape at the time of British colonisation. Nyoongar elder Noel Nannup approved culturally sensitive material and contributed his perspective on Aboriginal content to include in the exhibition. The initiative’s context remains pressing. In many ways, Perth has become a template for development in the metropolitan area (Weller). While not unusual for a capital, the rate of transformation is perhaps unexpected in a city less than 200 years old (Forster). There also remains a persistent view of existing wetlands as obstructions to progress that, once removed, are soon forgotten (Urban Bushland Council). Digital visualisation can contribute to appreciating environments prior to colonisation but also to re-imagining possibilities for future human interactions with land, water, and space. Despite the rapid pace of change, many Perth area residents have memories of wetlands lost during their lifetimes (for example, Giblett, Forrestdale). However, as the clearing and drainage of the inner city occurred early in settlement, recollections of urban wetlands exist exclusively in historical records. In 1935, a local correspondent using the name “Sandgroper” reminisced about swamps, connecting them to Perth’s colonial heritage: But the Swamps were very real in fact, and in name in the [eighteen-] Nineties, and the Perth of my youth cannot be visualised without them. They were, of course, drying up apace, but they were swamps for all that, and they linked us directly with the earliest days of the Colony when our great-grandparents had founded this City of Perth on a sort of hog's-back, of which Hay-street was the ridge, and from which a succession of streamlets ran down its southern slope to the river, while land locked to the north of it lay a series of lakes which have long since been filled to and built over so that the only evidence that they have ever existed lies in the original street plans of Perth prepared by Roe and Hillman in the early eighteen-thirties. A salient consequence of the loss of ecological memory is the tendency to repeat the miscues of the past, especially the blatant disregard for natural and cultural heritage, as suburbanisation engulfs the area. While the swamps of inner Perth remain only in the names of streets, existing wetlands in the metropolitan area are still being threatened, as the Roe Highway (Roe 8) Campaign demonstrates. To re-imagine Perth’s lost landscape, we used several colonial survey maps to plot the location of the original lakes and swamps. At this time, a series of interconnecting waterbodies, known as the Perth Great Lakes, spread across the north of the city (Bekle and Gentilli). This phase required the earliest cartographic sources (Figure 3) because, by 1855, city maps no longer depicted wetlands. We synthesised contextual information, such as well depths, geological and botanical maps, settlers’ accounts, Nyoongar oral histories, and colonial-era artists’ impressions, to produce renderings of Perth. This diverse collection of primary and secondary materials served as the basis for creating new images of the city. Team member Jeff Murray interpolated Balbuk’s route using historical mappings and accounts, topographical data, court records, and cartographic common sense. He determined that Balbuk would have camped on the high ground of the southern part of Lake Kingsford rather than the more inundated northern part (Figure 2). Furthermore, she would have followed a reasonably direct course north of St Georges Terrace (contrary to David Whish-Wilson’s imaginings) because she was barred from Government House for protesting. This easier route would have also avoided the springs and gullies that appear on early maps of Perth. Figure 3. Townsite of Perth in Western Australia by Colonial Draftsman A. Hillman and John Septimus Roe (1838). This map of Perth depicts the wetlands that existed overlaid by the geomentric grid of the new city. Image Credit: State Library of Western Australia (Image Number: BA1961/14). Additionally, we produced an animated display based on aerial photographs to show the historical extent of change. Prompted by the build up to World War II, the earliest aerial photography of Perth dates from the late 1930s (Dixon 148–54). As “Sandgroper” noted, by this time, most of the urban wetlands had been drained or substantially modified. The animation revealed considerable alterations to the formerly swampy Swan River shoreline. Most prominent was the transformation of the Matagarup shallows across the Swan River, originally consisting of small islands. Now traversed by a causeway, this area was transformed into a single island, Heirisson—the general site of Balbuk’s birth. The animation and accompanying materials (maps, images, and writings) enabled viewers to apprehend the changes in real time and to imagine what the city was once like. Re-imagining Perth’s Urban Heart The physical environment of inner Perth includes virtually no trace of its wetland origins. Consequently, we considered whether a representation of Perth, as it existed previously, could enhance public understanding of natural heritage and thereby increase its value. For this reason, interpretive materials were exhibited centrally at Perth Town Hall. Built partly by convicts between 1867 and 1870, the venue is close to the site of the 1829 Foundation of Perth, depicted in George Pitt Morrison’s painting. Balbuk’s grandfather “camped somewhere in the city of Perth, not far from the Town Hall” (Bates, “Fanny”). The building lies one block from the site of the railway station on the site of Lake Kingsford, the subsistence grounds of Balbuk and her forebears: The old swamp which is now the Perth railway yards had been a favourite jilgi ground; a spring near the Town Hall had been a camping place of Maiago […] and others of her fathers' folk; and all around and about city and suburbs she had gathered roots and fished for crayfish in the days gone by. (Bates, “Derelicts” 55) Beginning in 1848, the draining of Lake Kingsford reached completion during the construction of the Town Hall. While the swamps of the city were not appreciated by many residents, some organisations, such as the Perth Town Trust, vigorously opposed the reclamation of the lake, alluding to its hydrological role: That, the soil being sand, it is not to be supposed that Lake Kingsford has in itself any material effect on the wells of Perth; but that, from this same reason of the sandy soil, it would be impossible to keep the lake dry without, by so doing, withdrawing the water from at least the adjacent parts of the townsite to the same depth. (Independent Journal of Politics and News 3) At the time of our exhibition, the Lake Kingsford site was again being reworked to sink the railway line and build Yagan Square, a public space named after a colonial-era Nyoongar leader. The project required specialised construction techniques due to the high water table—the remnants of the lake. People travelling to the exhibition by train in October 2014 could have seen the lake reasserting itself in partly-filled depressions, flush with winter rain (Figure 4).Figure 4. Rise of the Repressed (2014). Water Rising in the former site of Lake Kingsford/Irwin during construction, corner of Roe and Fitzgerald Streets, Northbridge, WA. Image Credit: Nandi Chinna (2014). The exhibition was situated in the Town Hall’s enclosed undercroft designed for markets and more recently for shops. While some visited after peering curiously through the glass walls of the undercroft, others hailed from local and state government organisations. Guest comments applauded the alternative view of Perth we presented. The content invited the public to re-imagine Perth as a city of wetlands that were both environmentally and culturally important. A display panel described how the city’s infrastructure presented a hindrance for Balbuk as she attempted to negotiate the once-familiar route between Yoonderup and Lake Kingsford (Figure 2). Perth’s growth “restricted Balbuk’s wanderings; towns, trains, and farms came through her ‘line of march’; old landmarks were thus swept away, and year after year saw her less confident of the locality of one-time familiar spots” (Bates, “Fanny”). Conserving Wetlands: From Re-Claiming to Re-Valuing? Imagination, for philosopher Roger Scruton, involves “thinking of, and attending to, a present object (by thinking of it, or perceiving it, in terms of something absent)” (155). According to Scruton, the feelings aroused through imagination can prompt creative, transformative experiences. While environmental conservation tends to rely on data-driven empirical approaches, it appeals to imagination less commonly. We have found, however, that attending to the present object (the city) in terms of something absent (its wetlands) through evocative visual material can complement traditional conservation agendas focused on habitats and species. The actual extent of wetlands loss in the Swan Coastal Plain—the flat and sandy region extending from Jurien Bay south to Cape Naturaliste, including Perth—is contested. However, estimates suggest that 80 per cent of wetlands have been lost, with remaining habitats threatened by climate change, suburban development, agriculture, and industry (Department of Environment and Conservation). As with the swamps and lakes of the inner city, many regional wetlands were cleared, drained, or filled before they could be properly documented. Additionally, the seasonal fluctuations of swampy places have never been easily translatable to two-dimensional records. As Giblett notes, the creation of cartographic representations and the assignment of English names were attempts to fix the dynamic boundaries of wetlands, at least in the minds of settlers and administrators (Postmodern 72–73). Moreover, European colonists found the Western Australian landscape, including its wetlands, generally discomfiting. In a letter from 1833, metaphors failed George Fletcher Moore, the effusive colonial commentator, “I cannot compare these swamps to any marshes with which you are familiar” (220). The intermediate nature of wetlands—as neither land nor lake—is perhaps one reason for their cultural marginalisation (Giblett, Postmodern 39). The conviction that unsanitary, miasmic wetlands should be converted to more useful purposes largely prevailed (Giblett, Black 105–22). Felicity Morel-EdnieBrown’s research into land ownership records in colonial Perth demonstrated that town lots on swampland were often preferred. By layering records using geographic information systems (GIS), she revealed modifications to town plans to accommodate swampland frontages. The decline of wetlands in the region appears to have been driven initially by their exploitation for water and later for fertile soil. Northern market gardens supplied the needs of the early city. It is likely that the depletion of Nyoongar bush foods predated the flourishing of these gardens (Carter and Nutter). Engaging with the history of Perth’s swamps raises questions about the appreciation of wetlands today. In an era where numerous conservation strategies and alternatives have been developed (for example, Bobbink et al. 93–220), the exploitation of wetlands in service to population growth persists. On Perth’s north side, wetlands have long been subdued by controlling their water levels and landscaping their boundaries, as the suburban examples of Lake Monger and Hyde Park (formerly Third Swamp Reserve) reveal. Largely unmodified wetlands, such as Forrestdale Lake, exist south of Perth, but they too are in danger (Giblett, Black Swan). The Beeliar Wetlands near the suburb of Bibra Lake comprise an interconnected series of lakes and swamps that are vulnerable to a highway extension project first proposed in the 1950s. Just as the Perth Town Trust debated Lake Kingsford’s draining, local councils and the public are fiercely contesting the construction of the Roe Highway, which will bisect Beeliar Wetlands, destroying Roe Swamp (Chinna). The conservation value of wetlands still struggles to compete with traffic planning underpinned by a modernist ideology that associates cars and freeways with progress (Gregory). Outside of archives, the debate about Lake Kingsford is almost entirely forgotten and its physical presence has been erased. Despite the magnitude of loss, re-imagining the city’s swamplands, in the way that we have, calls attention to past indiscretions while invigorating future possibilities. We hope that the re-imagining of Perth’s wetlands stimulates public respect for ancestral tracks and songlines like Balbuk’s. Despite the accretions of settler history and colonial discourse, songlines endure as a fundamental cultural heritage. Nyoongar elder Noel Nannup states, “as people, if we can get out there on our songlines, even though there may be farms or roads overlaying them, fences, whatever it is that might impede us from travelling directly upon them, if we can get close proximity, we can still keep our culture alive. That is why it is so important for us to have our songlines.” Just as Fanny Balbuk plied her songlines between Yoonderup and Lake Kingsford, the traditional custodians of Beeliar and other wetlands around Perth walk the landscape as an act of resistance and solidarity, keeping the stories of place alive. Acknowledgments The authors wish to acknowledge Rod Giblett (ECU), Nandi Chinna (ECU), Susanna Iuliano (ECU), Jeff Murray (Kareff Consulting), Dimitri Fotev (City of Perth), and Brendan McAtee (Landgate) for their contributions to this project. The authors also acknowledge the traditional custodians of the lands upon which this paper was researched and written. References Bates, Daisy. “Fanny Balbuk-Yooreel: The Last Swan River (Female) Native.” The Western Mail 1 Jun. 1907: 45.———. “Oldest Perth: The Days before the White Men Won.” The Western Mail 25 Dec. 1909: 16–17.———. “Derelicts: The Passing of the Bibbulmun.” The Western Mail 25 Dec. 1924: 55–56. ———. “Aboriginal Perth.” The Western Mail 4 Jul. 1929: 70.———. “Hooper’s Fence: A Query.” The Western Mail 18 Apr. 1935: 9.———. The Passing of the Aborigines: A Lifetime Spent among the Natives of Australia. London: John Murray, 1966.Bekle, Hugo. “The Wetlands Lost: Drainage of the Perth Lake Systems.” Western Geographer 5.1–2 (1981): 21–41.Bekle, Hugo, and Joseph Gentilli. “History of the Perth Lakes.” Early Days 10.5 (1993): 442–60.Bobbink, Roland, Boudewijn Beltman, Jos Verhoeven, and Dennis Whigham, eds. Wetlands: Functioning, Biodiversity Conservation, and Restoration. Berlin: Springer-Verlag, 2006. Carter, Bevan, and Lynda Nutter. Nyungah Land: Records of Invasion and Theft of Aboriginal Land on the Swan River 1829–1850. Guildford: Swan Valley Nyungah Community, 2005.Chinna, Nandi. “Swamp.” Griffith Review 47 (2015). 29 Sep. 2015 ‹https://griffithreview.com/articles/swamp›.Department of Environment and Conservation. Geomorphic Wetlands Swan Coastal Plain Dataset. Perth: Department of Environment and Conservation, 2008.Dixon, Robert. Photography, Early Cinema, and Colonial Modernity: Frank Hurley’s Synchronized Lecture Entertainments. London: Anthem Press, 2011. Forster, Clive. Australian Cities: Continuity and Change. Oxford: Oxford UP, 2004.Giblett, Rod. Postmodern Wetlands: Culture, History, Ecology. Edinburgh: Edinburgh UP, 1996. ———. Forrestdale: People and Place. Bassendean: Access Press, 2006.———. Black Swan Lake: Life of a Wetland. Bristol: Intellect, 2013.———. Cities and Wetlands: The Return of the Repressed in Nature and Culture. London: Bloomsbury, 2016. 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(Quoted material transcribed from 3.08–3.39 of the video.) O’Connor, Rory, Gary Quartermaine, and Corrie Bodney. Report on an Investigation into Aboriginal Significance of Wetlands and Rivers in the Perth-Bunbury Region. Perth: Western Australian Water Resources Council, 1989.Reece, Bob. “‘Killing with Kindness’: Daisy Bates and New Norcia.” Aboriginal History 32 (2008): 128–45.Rose, Deborah Bird. Nourishing Terrains: Australian Aboriginal Views of Landscape and Wilderness. Canberra: Australian Heritage Commission, 1996.Sanderson, Eric. Mannahatta: A Natural History of New York City. New York: Harry N. Abrams, 2009.Sandgroper. “Gilgies: The Swamps of Perth.” The West Australian 4 May 1935: 7.Scruton, Roger. Art and Imagination. London: Methuen, 1974.Seddon, George. Sense of Place: A Response to an Environment, the Swan Coastal Plain, Western Australia. Melbourne: Bloomings Books, 2004.South West Aboriginal Land and Sea Council and John Host with Chris Owen. “It’s Still in My Heart, This is My Country:” The Single Noongar Claim History. Crawley: U of Western Australia P, 2009.Urban Bushland Council. “Bushland Issues.” 2015. 29 Sep. 2015 ‹http://www.bushlandperth.org.au/bushland-issues›.Welborn, Suzanne. Swan: The History of a Brewery. Crawley: U of Western Australia P, 1987.Weller, Richard. Boomtown 2050: Scenarios for a Rapidly Growing City. Crawley: U of Western Australia P, 2009. Whish-Wilson, David. Perth. Sydney: NewSouth Publishing, 2013.

Sisal (Agave sisalana Perrine) is an important hard fiber crop that is widely planted in Guangxi, Guangdong, Hainan, Yunnan, and Fujian provinces, China. In July 2019, a new leaf disease of sisal with a disease incident of about 36% was found in Guangxi (Fig.1a~d). The oval or circular black lesions were 2.3 cm to 15.9 cm in length and 1.6 cm to 5.5 cm in width on both sides of the diseased leaves. The central part of the lesions was slightly hollow. The lesions continuously enlarged and ultimately penetrated the leaves. Reddish brown and dark mucus was secreted from the lesions. The junction of lesions and healthy parts was reddish brown to yellow. The diseased leaf fiber and mesophyll tissues were reddish brown and necrotic. Fresh leaf yield was reduced about 30% by the disease, and fiber quality was significantly compromised every year in Guangxi. Six kinds of fungi distinguished by their morphology, size and color of the colonies were isolated from diseased leaf tissues of 60 sisal plants sampled from five different farms in Guangxi. Isolate JMHB1 was isolated at a rate of 95.67%. The isolate JMHB1 was initially white with dense and hairy aerial mycelium, gradually turning dark grey to olive green on PDA (Fig. 2). Conidia, arthrospores, and chlamydospores were observed on PDA in culture (Fig. 3). The conidia formed arthric chains, disarticulating, cylindrical-truncate, oblong-obtuse to doliiform, colorless and transparent, zero- to one-septate, and averaging 4.4 to 13.8 µm × 2.2 to 5.6 µm (n=100). Arthrospores were short columnar, pigmented and transparent, single or formed arthric chains, averaging 5.5 to 17.9 µm × 2.1 to 3.5 µm (n=100). Chlamydospores were dark brown, round or oval, averaging 4.5 to 9.6 µm × 4.5 to 8.6 µm (n=100). Pathogenicity testing was conducted by inoculating 3-year-old healthy sisal plants with PDA plugs (5 × 5 mm) on which the fungus had grown for 5 days. Nine healthy plants were wounded on the leaves with a sterile needle, and mycelial plugs were placed on the wounds, covered with sterile moist cotton, and wrapped with parafilm. Nine control plants were wounded and treated with PDA plugs as the negative control. The test was repeated three times. All treated plants were kept in a greenhouse at ~28 ℃ and 40% RH. After 5 days, only leaves inoculated with isolate JMHB1 showed lesions similar to symptoms observed in the field (Fig.1e~f). The fungus was re-isolated from all nine diseased plants, and no symptoms were observed on the leaves of control plants. Molecular identification of the fungus was made by PCR amplification of the internal transcribed spacer (ITS) region of rDNA, EF1-α gene and β-tubulin gene using primers ITS1/ITS4 (White et al. 1990), EFl-728F/EF1-986R (Carbone and Kohn 1999), TUB2Fd/TUB4Rd (Aveskamp et al. 2009) respectively. The ITS (MT705646), EF1-α (MT733516) and β-tubulin (MT773603) sequences of JMHB1 were similar to the ITS (AY819727), EF1-α (EU144063) and β-tubulin (KF531800) sequences of the epitype of Neoscytalidium dimidiatum (CBS 499.66) with 100%, 99.65% and 99.02% identity, respectively. Based on pathogenicity testing, morphological characteristics, and molecular identification, the pathogen of sisal causing black spot was identified as N. dimidiatum (Penz.) Crous & Slippers (Crous et al. 2006). To our knowledge, this is the first report of black spot caused by N. dimidiatum on sisal in China. Sisal is the main economic crop in arid and semi-arid areas that is widely planted in several provinces of southern China. The serious occurrence of the disease caused by N. dimidiatum has greatly affected the development of sisal industry and local economic income in China. Identification of the pathogen of the disease is of great significance to guide disease control, increase farmers' income and promote the development of sisal industry. References: Aveskamp, M. M., et al. 2009. Mycologia, 101: 363. https://doi.org/10.3852/08-199. Carbone, I., and Kohn, L. M. 1999. Mycologia, 91:553. https://doi.org/10.1080/00275514.1999. 12061051. Crous, P. W., et al. 2006. Stud. Mycol. 55:235. https://doi.org/10.3114/sim.55.1.235. White, T. J., et al. 1990. PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, Page 315. doi.org/10.1002/mrd.1080280418. Supplemental photographs: Fig. 1 Symptoms of sisal black spot disease a, b, c, d showed symptoms in the field, e and f were symptoms after inoculating Neoscytalidium dimidiatum JMHB1. a, c, and e were the front of the lesions, b, d, and f were the back of the lesions. Fig. 2 Primary colony (a) and old colony (b) of Neoscytalidium dimidiatum JMHB1 Fig. 3 Arthrospores (a), conidia and chlamydospores (b) of Neoscytalidium dimidiatum JMHB1

IntroductionNew Orleans is one of a number of infamous swamp cities—cities built in swamps, near them or on land “reclaimed” from them, such as London, Paris, Venice, Boston, Chicago, Washington, Petersburg, and Perth. New Orleans seemed to be winning the battle against the swamps until Hurricane Katrina of 2005, or at least participating in an uneasy truce between its unviable location and the forces of the weather to the point that the former was forgotten until the latter intruded as a stark reminder of its history and geography. Around the name “Katrina” a whole series of events and images congregate, including those of photographer Robert Polidori in his monumental book, After the Flood. Katrina, and the exacerbating factors of global warming and drained wetlands, and their impacts, especially on the city of New Orleans (both its infrastructure and residents), point to the cultural construction and production of the disaster. This suite of occurrences is a salutary instance of the difficulties of trying to maintain a hard and fast divide between nature and culture (Hirst and Woolley 23; Giblett, Body 16–17) and the need to think and live them together (Giblett, People and Places). A hurricane is in some sense a natural event, but in the age of global warming it is also a cultural occurrence; a flood produced by a river breaking its banks is a natural event, but a flood caused by breeched levees and drained wetlands is a cultural occurrence; people dying is a natural event, but people dying by drowning in a large and iconic American city created by drainage of wetlands is a cultural disaster of urban planning and relief logistics; and a city set in a swamp is natural and cultural, with the cultural usually antithetical to the natural. “Katrina” is a salutary instance of the cultural and natural operating together in and as “one single catastrophe” of history, as Benjamin (392) put it, and of geography I would add in the will to fill, drain, or reclaim wetlands. Rather than a series of catastrophes proceeding one after the other through history, Benjamin's (392) “Angel of History” sees one single catastrophe of history. This single catastrophe, however, occurs not only in time, in history, but also in space, in a place, in geography. The “Angel of Geography” sees one single catastrophe of geography of wetlands dredged, filled, and reclaimed, cities set in them and cities being re-reclaimed by them in storms and floods. In the case of “Katrina,” the catastrophe of history and geography is tied up with the creation, destruction, and recreation of New Orleans in its swampy location on the Mississippi delta.New OrleansNew Orleans is not only “the nation’s quintessential river city” as Kelman (199) puts it, but also one of a number of infamous swamp cities. In his post-Katrina preface to his study of New Orleans as what he calls “an unnatural metropolis,” Colten notes:While other cities have occupied wetlands, few have the combination of poorly-drained and flood-susceptible territory of New Orleans. Portions of Washington, D.C. occupied wetlands, but there was ample solid ground above the reach of the Potomac [River’s] worst floods. Chicago’s founders platted their city on a wetland site, but the sluggish Chicago River did not drain the massive territory of the Mississippi. (5)“Occupied” is arguably a euphemism for dredging, draining, filling, and reclaiming wetlands. Occupation also conjures up visions of an occupying army, which may be appropriate in the case of New Orleans as the Army Corps of Engineers have spearheaded much of the militarisation by dredging and draining wetlands in New Orleans and elsewhere in the U.S.The location for the city was not propitious. Wilson describes how “the city itself was constructed on an uneven patch of relatively high ground in the midst of a vast swamp” (86). New Orleans for Kelman “is surrounded by a wet world composed of terrain that is not quite land” (22) with the Mississippi River delta on one side and Lake Pontchartrain and the “backswamps” on the other, though the latter were later drained. The Mississippi River for Kelman is “the continent’s most famed and largest watercourse” (199). Perhaps it is also the continent’s most tamed and leveed watercourse. Earlier Kelman related how a prominent local commentator in 1847 “personified the Mississippi as a nurturing mother” because the river “hugged New Orleans to its ‘broad bosom’” (79). Supposedly this mother was the benign, malign, and patriarchal Mother Nature of the leveed river and not the recalcitrant, matrifocal Great Goddess of the swamps that threatened to break the levees and flood the city (see Giblett, Postmodern Wetlands; People and Places, especially Chapter 1). The Mississippi as the mother of all American rivers gave birth to the city of New Orleans at her “mouth,” or more precisely at the other end of her anatomy with the wetland delta as womb. Because of its location at the “mouth” of the Mississippi River, New Orleans for Flint was “historically the most important port in the United States” (230). Yet by the late 1860s the river was seen by New Orleanians, Kelman argues, only as “an alimentary canal, filled with raw waste and decaying animal carcasses” (124). The “mouth” of the river had ceased to be womb and had become anus; the delta had ceased to be womb and had become bowel. The living body of the earth was dying. The river, Kelman concludes, was “not sublime” and had become “an interstate highway” (146). The Angel of Geography sees the single catastrophe of wetlands enacted in the ways in which the earth is figured in a politics of spaces and places. Ascribing the qualities of one place to another to valorise one place and denigrate another and to figure one pejoratively or euphemistically (as in this case) is “placist” (Giblett, Landscapes 8 and 36). Deconstructing and decolonising placism and its use of such figures can lead to a more eco-friendly figuration of spaces and places. New Orleans is one place to do so.What Colten calls “the swampy mire behind New Orleans” was drained in the first 40 years of the twentieth century (46). Colten concludes that, “by the 1930s, drainage and landfilling efforts had successfully reclaimed wetland between the city and the lake, and in the post-war years similar campaigns dewatered marshlands for tract housing eastward and westward from the city” (140–1). For Wilson “much of New Orleans’s history can be seen as a continuing battle with the swamp” (86). New Orleans was a frontline in the modern war against wetlands, the kind of war that Fascists such as Mussolini liked to fight because they were so easy to win (see Giblett, Postmodern Wetlands 115). Many campaigns were fought against wetlands using the modern weapons of monstrous dredgers. The city had struck what Kelman calls “a Faustian bargain with the levees-only policy” (168). In other words, it had sold its soul to the devil of modern industrial technology in exchange for temporary power. New Orleans tried to dominate wetlands with the ironic result that not only “efforts to drain the city dominate early New Orleans history into the present day” as Wilson (86) puts it, but also that these efforts occasionally failed with devastating results. The city became dominated by the waters it had sought to dominate in an irony of history and geography not lost on the student of wetlands. Katrina was the means that reversed the domination of wetlands by the city. Flint argues that “Katrina’s wake-up call made it unconscionable to keep building on fragile coastlines […] and in floodplains” (232–3). And in swamps, I would add. Colten “traces the public’s abandonment of the belief that the city is no place for a swamp” (163). The city is also no place for the artificial swamp of the aftermath of Katrina depicted by Polidori. As the history of New Orleans attests, the swamp is no place for a city in the first place when it is being built, and the city is no place for a swamp in the second place when it is being ravaged by a hurricane and storm surges. City is antithetical and inimical to swamp. They are mutually exclusive. New Orleans for Wilson is “a city on a swamp” (90 my emphasis). In the 1927 flood (Wilson 111), for Kelman “one of the worst flood years in history” (157), and in the 2005 hurricane, the worst flood year so far in its history, New Orleans was transformed into a city of a swamp. The 1927 flood was at the time, and as Kelman puts it, “the worst ‘natural’ disaster in U.S. history” (161), only to be surpassed by the 2005 flood in New Orleans and the 2012 floods in north-eastern U.S. in the wake of Superstorm Sandy in which the drained marshlands of New York and New Jersey returned with a vengeance. In all these cases the swamp outside the city, or before the city, came into the city, became now. The swamp in the past returned in the present; the absent swamp asserted its presence. The historical barriers between city and swamp were removed. KatrinaKatrina for Kelman (xviii) was not a natural disaster. Katrina produced “water […] out of place” (Kelman x). In other words, and in Mary Douglas’s terms for whom dirt is matter out of place (Douglas 2), this water was dirt. It was not merely that the water was dirty in colour or composition but that the water was in the wrong place, in the buildings and streets, and not behind levees, as Polidori graphically illustrates in his photographs. Bodies were also out of place with “corpses floating in dirty water” (Kelman x) (though Polidori does not photograph these, unlike Dean Sewell in Aceh in the aftermath of the Asian tsunami in what I call an Orientalist pornography of death (Giblett, Landscapes 158)). Dead bodies became dirt: visible, smelly, water-logged. Colten argues that “human actions […] make an extreme event into a disaster […]. The extreme event that became a disaster was not just the result of Katrina but the product of three centuries of urbanization in a precarious site” (xix). Yet Katrina was not only the product of three centuries of urbanisation of New Orleans’ precarious and precious watershed, but also the product of three centuries of American urbanisation of the precarious and precious airshed through pollution with greenhouse gases.The watery geographical location of New Orleans, its history of drainage and levee-building, the fossil-fuel dependence of modern industrial capitalist economies, poor relief efforts and the storm combined to produce the perfect disaster of Katrina. Land, water, and air were mixed in an artificial quaking zone of elements not in their normal places, a feral quaking zone of the elements of air, earth and water that had been in the native quaking zone of swamps now ran amok in a watery wasteland (see Giblett, Landscapes especially Chapter 1). Water was on the land and in the air. In the beginning God, when created the heavens and the earth, darkness and chaos moved over the face of the waters, and the earth was without form and void in the geographical location of a native quaking zone. In the ending, when humans are recreating the heavens and the earth, darkness and chaos move over the face of the waters, and the earth is without form and void in the the geographical location and catastrophe of a feral quaking zone. Humans were thrown into this maelstrom where they quaked in fear and survived or died. Humans are now recreating the city of New Orleans in the aftermath of “Katrina.” In the beginning of the history of the city, humans created the city; from the disastrous destruction of some cities, humans are recreating the city.It is difficult to make sense of “Katrina.” Smith relates that, “as well as killing some 1500 people, the bill for the devastation wrought by Hurricane Katrina on New Orleans […] was US$200 billion, making it the most costly disaster in American history,” more than “9/11” (303; see also Flint 230). A whole series of events and images congregate around the name “Katrina,” including those of photographer Robert Polidori in his book of photographs, After the Flood, with its overtones of divine punishment for human sin as with the biblical flood (Coogan et al. Genesis, Chapters 6–7). The flood returns the earth to the beginning when God created heaven and earth, when “the earth was without form and darkness moved […] upon the face of the waters” (Coogan et al. Genesis Chapter 1, Verse 2)—God's first, and arguably best, work (Giblett, Postmodern Wetlands 142–143; Canadian Wetlands “Preface”). The single catastrophe of history and geography begins here and now in the act of creation on the first day and in dividing land from water as God also did on the second day (Coogan et al. Genesis Chapter 1, Verse 7)—God’s second, and arguably second best, work. New Orleans began in the chaos of land and water. This chaos recurs in later disasters, such as “Katrina,” which merely repeat the creation and catastrophe of the beginning in the eternal recurrence of the same. New Orleans developed by dividing land from water and is periodically flooded by the division ceasing to be returning the city to its, and the, beginning but this time inflected as a human-made “swamp,” a feral quaking zone (Giblett, Landscapes Chapter 1). Catastrophe and creativity are locked together from the beginning. The creation of the world as wetland and the separation of land and water was a catastrophic action on God's part. Its repetition in the draining or filling of wetlands is a catastrophic event for the heavens and earth, and humans, as is the unseparation of land and water in floods. What Muecke calls the rhetoric of “natural disaster” (259, 263) looms large in accounts of “Katrina.” In an escalating scale of hyperbole, “Katrina” for Brinkley was a “natural disaster” (5, 60, 77), “the worst natural disaster in modern U.S. history” (62), “the biggest natural disaster in recent American history” (273), and “the worst natural disaster in modern American history” (331). Yet a hurricane in and by itself is not a disaster. It is a natural event. Perhaps all that could simply be said is that “Katrina was one of the most powerful storms ever recorded in U.S. history” (Brinkley 73). Yet to be recorded in U.S. history “Katrina” had to be more than just a storm. It had also to be more than merely what Muecke calls an “oceanic disaster” (259) out to sea. It had to have made land-fall, and it had to have had human impact. It was not merely an event in the history of weather patterns in the U.S. For Brinkley “the hurricane disaster was followed by the flood disaster, which was followed by human disasters” (249). These three disasters for Brinkley add up to “the overall disaster, the sinking of New Orleans, [which] was a man-made disaster, resulting from poorly designed and managed levees and floodwalls” (426). The result was that for Brinkley “the man-made misery was worse than the storm” (597). The flood and the misery amount to what Brinkley calls “the Great Deluge [which] was a disaster that the country brought on itself” (619). The storm could also be seen as a disaster that the country brought on itself through the use of fossil fuels. The overall disaster comprising the hurricane the flood, the sinking city and its drowning or displaced inhabitants was preceded and made possible by the disasters of dredging wetlands and of global warming. Brinkley cites the work of Kerry Emanuel and concludes that “global warming makes bad hurricanes worse” (74). Draining wetlands also makes bad hurricanes worse as “miles of coastal wetlands could reduce hurricane storm surges by over three or four feet” (Brinkley 10). Miles of coastal wetlands, however, had been destroyed. Brinkley relates that “nearly one million acres of buffering wetlands in southern Louisiana disappeared between 1990 and 2005” (9). They “disappeared” as the result, not of some sort of sleight of hand or mega-conjuring trick, nor of erosion from sea-intrusion (though that contributed), but of deliberate human practice. Brinkley relates how “too many Americans saw these swamps and coastal wetlands as wastelands” (9). Wastelands needed to be redeemed into enclave estates of condos and strip developments. In a historical irony that is not lost on students of wetlands and their history, destroying wetlands can create the wasteland of flooded cities and a single catastrophe of history and geography, such as New Orleans in the aftermath of Hurricane Katrina.In searching for a trope to explain these events Brinkley turns to the tried and true figure of the monster, usually feminised, and “Katrina” is no exception. For him, “Hurricane Katrina had been a palpable monster, an alien beast” (Brinkley xiv), “a monstrous hurricane” (72), “a monster hurricane” (115), and “the monster storm” (Brinkley 453 and Flint 230). A monster, according to The Concise Oxford Dictionary (Allen 768), is: (a) “an imaginary creature, usually large and frightening, composed of incongruous elements; or (b) a large or ugly or misshapen animal or thing.” Katrina was not imaginary, though it or she was and has been imagined in a number of ways, including as a monster. “She” was certainly large and frightening. “She” was composed of the elements of air and water. These may be incongruous elements in the normal course of events but not for a hurricane. “She” certainly caused ugliness and misshapenness to those caught in her wake of havoc, but aerial photographs show her to be a perfectly shaped hurricane, albeit with a deep and destructive throat imaginable as an orally sadistic monster. ConclusionNew Orleans, as Kelman writes in his post-Katrina preface, “has a horrible disaster history” (xii) in the sense that it has a history of horrible disasters. It also has a horrible history of the single disaster of its swampy location. Rather than “a chain of events that appears before us,” “the Angel of History” for Benjamin “sees one single catastrophe which keeps piling wreckage upon wreckage” (392). Rather than a series of disasters of the founding, drainage, disease, death, floods, hurricanes, etc. that mark the history of New Orleans, the Angel of History sees a single, catastrophic history, not just of New Orleans but preceding and post-dating it. This catastrophic history and geography began in the beginning when God created the heavens and the earth, darkness and chaos moved over the face of the waters, the earth was without form and void, and when God divided the land from the water, and is ending in industrial capitalism and its technologies, weather, climate, cities, floods, rivers, and wetlands intertwining and inter-relating together as entities and agents. Rather than a series of acts and sites of creativity and destruction that appear before us, the Angel of Geography sees one single process and place which keeps (re)creating order out of chaos and chaos out of order. This geography and history began at the beginning when God created the heavens and the earth, and the wetland, and divided land from water, and continues when and as humans drain(ed) wetlands, create(d) cities, destroy(ed) cites, rebuilt/d cities and rehabilitate(d) wetlands. “Katrina” is a salutary instance of the cultural and natural operating together in the one single catastrophe and creativity of divine and human history and geography.ReferencesAllen, Robert. The Concise Oxford Dictionary. 8th ed. Oxford: Clarendon Press, 1990.Benjamin, Walter. “On the Concept of History.” Selected Writings Volume 4: 1938–1940. Eds. Howard Eiland and Michael W. Jennings. Cambridge, MA: The Belknap Press of Harvard UP, 2003. 389–400.Brinkley, Douglas. 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