Siga este enlace para ver otros tipos de publicaciones sobre el tema: Vegetation disturbance.
Artículos de revistas sobre el tema "Vegetation disturbance"
Crea una cita precisa en los estilos APA, MLA, Chicago, Harvard y otros
Consulte los 50 mejores artículos de revistas para su investigación sobre el tema "Vegetation disturbance".
Junto a cada fuente en la lista de referencias hay un botón "Agregar a la bibliografía". Pulsa este botón, y generaremos automáticamente la referencia bibliográfica para la obra elegida en el estilo de cita que necesites: APA, MLA, Harvard, Vancouver, Chicago, etc.
También puede descargar el texto completo de la publicación académica en formato pdf y leer en línea su resumen siempre que esté disponible en los metadatos.
Explore artículos de revistas sobre una amplia variedad de disciplinas y organice su bibliografía correctamente.
1
Patten, Robin. "Analysis of the Relationship between Natural Disturbance and Vegetation Patterns in Cascade Canyon, Grand Teton National Park". UW National Parks Service Research Station Annual Reports 9 (1 de enero de 1985): 96–97. http://dx.doi.org/10.13001/uwnpsrc.1985.2501.
Texto completoResumen
The steep-walled valleys of the Tetons are subject to frequent natural disturbances, including avalanches, rockfall, and debris flow. The vegetation patterns of these valleys are a function of these disturbance events, with the distribution of the community types being controlled by both environmental factors and the disturbance regime. This project will analyze the relationship between disturbances and vegetation patterns in order to determine how the type, frequency, and magnitude of disturbance affects vegetation. This information should lead to an understanding of how vegetation patterns are created and how they change through time.
2
Zhang, Xianliang y Xuanrui Huang. "Human disturbance caused stronger influences on global vegetation change than climate change". PeerJ 7 (25 de septiembre de 2019): e7763. http://dx.doi.org/10.7717/peerj.7763.
Texto completoResumen
Global vegetation distribution has been influenced by human disturbance and climate change. The past vegetation changes were studied in numerous studies while few studies had addressed the relative contributions of human disturbance and climate change on vegetation change. To separate the influences of human disturbance and climate change on the vegetation changes, we compared the existing vegetation which indicates the vegetation distribution under human influences with the potential vegetation which reflects the vegetation distribution without human influences. The results showed that climate-induced vegetation changes only occurred in a few grid cells from the period 1982–1996 to the period 1997–2013. Human-induced vegetation changes occurred worldwide, except in the polar and desert regions. About 3% of total vegetation distribution was transformed by human activities from the period 1982–1996 to the period 1997–2013. Human disturbances caused stronger damage to global vegetation change than climate change. Our results indicated that the regions where vegetation experienced both human disturbance and climate change are eco-fragile regions.
3
Crausbay, Shelley D. y Patrick H. Martin. "Natural disturbance, vegetation patterns and ecological dynamics in tropical montane forests". Journal of Tropical Ecology 32, n.º 5 (14 de julio de 2016): 384–403. http://dx.doi.org/10.1017/s0266467416000328.
Texto completoResumen
Abstract:Disturbance is a central process in forest dynamics, yet the role of natural disturbance in tropical montane forests (TMFs) has not been systematically addressed. We posit that disturbance in TMFs has a wider role than commonly acknowledged and its effects are distinctive because: (1) TMFs often have very low rates of productivity due to low resources, and so recovery from disturbance may be slow, (2) montane forests have marked environmental heterogeneity which interacts with disturbance, (3) a large percentage of TMFs are regularly exposed to high energy windstorms and landslides, and (4) TMFs contain a biogeographically rich mixture of tree species with divergent evolutionary histories that interact differently with different disturbance types. We reviewed the literature on natural disturbance in TMFs and found 119 peer-reviewed papers which met our search criteria. Our review shows that disturbance is widespread in TMFs with pronounced effects on structure, function, composition and dynamics. Disturbance is also evident in the ecology of TMF biota with clear examples of plant life-history traits adapted to disturbance, including disturbance-triggered germination, treefall gap strategies and resprouting ability. Important aspects of TMF disturbances are stochastic and site-specific, but there are broad patterns in disturbance type, frequency and severity along latitudinal, altitudinal and environmental gradients. Compared with the lowland tropics, TMF disturbances are more spatially structured, TMFs experience more disturbance types in a given area due to environmental complexity, and TMFs are much more prone to small-scale yet severe landslides as well the large and potentially catastrophic disturbances of cyclones, forest die-back and fire. On the whole, natural disturbance should assume a larger role in models of ecosystem processes and vegetation patterns in TMFs. An improved understanding of what creates variation in disturbance severity and post-disturbance recovery rates, how composition and diversity feedback on disturbance type and likelihood, and how global change will alter these dynamics are important priorities in future TMF ecology research.
4
Bueno, Inacio T., Greg J. McDermid, Eduarda M. O. Silveira, Jennifer N. Hird, Breno I. Domingos y Fausto W. Acerbi Júnior. "Spatial Agreement among Vegetation Disturbance Maps in Tropical Domains Using Landsat Time Series". Remote Sensing 12, n.º 18 (11 de septiembre de 2020): 2948. http://dx.doi.org/10.3390/rs12182948.
Texto completoResumen
Detecting disturbances in native vegetation is a crucial component of many environmental management strategies, and remote sensing-based methods are the most efficient way to collect multi-temporal disturbance data over large areas. Given that there is a large range of datasets for monitoring, analyzing, and detecting disturbances, many methods have been well-studied and successfully implemented. However, factors such as the vegetation type, input data, and change detection method can significantly alter the outcomes of a disturbance-detection study. We evaluated the spatial agreement of disturbance maps provided by the Breaks For Additive Season and Trend (BFAST) algorithm, evaluating seven spectral indices in three distinct vegetation domains in Brazil: Atlantic forest, savanna, and semi-arid woodland, by assessing levels of agreement between the outputs. We computed individual map accuracies based on a reference dataset, then ranked their performance, while also observing their relationships with specific vegetation domains. Our results indicated a low rate of spatial agreement among index-based disturbance maps, which itself was minimally influenced by vegetation domain. Wetness indices produced greater detection accuracies in comparison to greenness-related indices free of saturation. The normalized difference moisture index performed best in the Atlantic forest domains, yet performed poorest in semi-arid woodland, reflecting its specific sensitivity to vegetation and its water content. The normalized difference vegetation index led to high disturbance detection accuracies in the savanna and semi-arid woodland domains. This study offered novel insight into vegetation disturbance maps, their relationship to different ecosystem types, and corresponding accuracies. Distinct input data can produce non-spatially correlated disturbance maps and reflect site-specific sensitivity. Future research should explore algorithm limitations presented in this study, as well as the expansion to other techniques and vegetation domains across the globe.
5
Berger, Alaina L., Klaus J. Puettmann y George E. Host. "Harvesting impacts on soil and understory vegetation: the influence of season of harvest and within-site disturbance patterns on clear-cut aspen stands in Minnesota". Canadian Journal of Forest Research 34, n.º 10 (1 de octubre de 2004): 2159–68. http://dx.doi.org/10.1139/x04-097.
Texto completoResumen
We investigated impacts of harvesting on soil disturbance and vegetation in the aspen cover type of northern Minnesota, United States. The soil disturbance (resistance to penetration) and understory vegetation were characterized for 19 sites on five 60-m2 plots placed along a disturbance gradient: landings (high harvesting traffic), skid trails (intermediate harvesting traffic), and areas off skid trails (low to no harvesting traffic). Penetration levels were quite variable, but they still indicated that within-site responses to disturbance patterns created by clear-cut harvesting were not uniform. In general, soil disturbance and understory species composition within landings were similar to those with skid trails. The soil disturbance and vegetation composition of these two levels differed from those of the low-disturbance plots (off skid trails), indicating that removing trees alone did not affect vegetation composition as much as creating an established skid trail, regardless of harvest timing. However, sites with more variable species composition (winter-harvested sites) and lower disturbance levels were less altered than sites with likely lower initial diversity (summer-harvested sites). The results suggest that it is important for recovery of understory plant communities to not only limit the amount and level of disturbances but also consider the spatial layout of harvesting, thus maintaining a spatially connected network of remnant forest patches large enough to contain interior forest species.
6
Sahib, Nargis, Laïla Rhazi y Patrick Grillas. "Post-disturbance dynamics of plant communities in a Mediterranean temporary pool (Western Morocco): Effects of disturbance size". Botany 89, n.º 2 (febrero de 2011): 105–18. http://dx.doi.org/10.1139/b10-091.
Texto completoResumen
Mediterranean temporary pools are frequently visited habitats where domestic livestock and wild herbivores generate numerous physical soil disturbances. Using two sizes of experimental plots (large, 1.20 m × 1.20 m; small, 0.3 m × 0.3 m), the effects of soil disturbances on vegetation dynamics and the vertical distribution of seeds were studied in one Moroccan temporary pool. Results show a very rapid regeneration of temporary wetland vegetation in disturbed plots. The speed of regeneration depends on the size of disturbance and hydrology. There was an almost complete return of vegetation to the reference state in the small disturbed plots by the end of the 1st year. This fast restoration was mainly due to seed banks, which play a key role in the resilience of pools to the different sizes of disturbances frequently generated by herbivores, but also to lateral colonization by perennials.
7
Burton, Chantelle, Richard Betts, Manoel Cardoso, Ted R. Feldpausch, Anna Harper, Chris D. Jones, Douglas I. Kelley, Eddy Robertson y Andy Wiltshire. "Representation of fire, land-use change and vegetation dynamics in the Joint UK Land Environment Simulator vn4.9 (JULES)". Geoscientific Model Development 12, n.º 1 (9 de enero de 2019): 179–93. http://dx.doi.org/10.5194/gmd-12-179-2019.
Texto completoResumen
Abstract. Disturbance of vegetation is a critical component of land cover, but is generally poorly constrained in land surface and carbon cycle models. In particular, land-use change and fire can be treated as large-scale disturbances without full representation of their underlying complexities and interactions. Here we describe developments to the land surface model JULES (Joint UK Land Environment Simulator) to represent land-use change and fire as distinct processes which interact with simulated vegetation dynamics. We couple the fire model INFERNO (INteractive Fire and Emission algoRithm for Natural envirOnments) to dynamic vegetation within JULES and use the HYDE (History Database of the Global Environment) land cover dataset to analyse the impact of land-use change on the simulation of present day vegetation. We evaluate the inclusion of land use and fire disturbance against standard benchmarks. Using the Manhattan metric, results show improved simulation of vegetation cover across all observed datasets. Overall, disturbance improves the simulation of vegetation cover by 35 % compared to vegetation continuous field (VCF) observations from MODIS and 13 % compared to the Climate Change Initiative (CCI) from the ESA. Biases in grass extent are reduced from −66 % to 13 %. Total woody cover improves by 55 % compared to VCF and 20 % compared to CCI from a reduction in forest extent in the tropics, although simulated tree cover is now too sparse in some areas. Explicitly modelling fire and land use generally decreases tree and shrub cover and increases grasses. The results show that the disturbances provide important contributions to the realistic modelling of vegetation on a global scale, although in some areas fire and land use together result in too much disturbance. This work provides a substantial contribution towards representing the full complexity and interactions between land-use change and fire that could be used in Earth system models.
8
Wilson, B. A. y G. R. Friend. "Responses of Australian Mammals to Disturbance: A Review." Australian Mammalogy 21, n.º 1 (1999): 87. http://dx.doi.org/10.1071/am99087.
Texto completoResumen
The Australian native mammal fauna has evolved in an environment where 'natural' or endogenous disturbance is ongoing and widespread, be it fire, flood, drought or cyclones. Since European settlement, however, the type, scale, frequency and intensity of disturbance has changed and added a new suite of exogenous impacts including introduced predators and herbivores, vegetation clearance, habitat fragmentation, altered fire regimes, grazing and timber harvesting. This has presented novel and significant adaptive challenges to native mammals over a compressed time-scale, resulting in major extinctions, population declines and disruption to community structure. In this paper we examine the ecology of Australian mammals in the context of these new disturbances, and compare the response patterns observed, and assess the processes operating. In general, Australian mammalian successional patterns are closely tied to vegetation regeneration, which is related to the degree of disruption. Disturbances such as predation do not fall within this pattern. Mammalian successional states vary between different disturbance types within an ecosystem, depending on the critical elements of vegetation structure and composition. Landscape and climatic factors also affect successional patterns and need to be further investigated.
9
Chambers, Jeanne C. "Seed and vegetation dynamics in an alpine herb field: effects of disturbance type". Canadian Journal of Botany 71, n.º 3 (1 de marzo de 1993): 471–85. http://dx.doi.org/10.1139/b93-052.
Texto completoResumen
Relationships among the aboveground vegetation, seed rain, and seed bank were examined on a late seral herb field characterized by pocket gopher disturbance and on an early seral gravel borrow that had been severely disturbed 35 years ago on the Beartooth Plateau, Montana. Aboveground vegetation cover was assessed by species in twelve 5-m2 plots. Seed rain was sampled during the 1988, 1989, and 1990 growing seasons with pitfall traps, and the soil seed bank was sampled in fall 1989, spring 1990, and fall 1990. The seed rain (filled seeds) on the borrow area ranged from 7730 to 14 009 seeds/m2 and was higher than that found on other alpine sites; that on the Geum turf ranged from 3375 to 6179 seeds/m2 and was similar to that for other alpine sites. Although highly variable among dates on the borrow area, the seed banks were similar to those of comparable alpine sites. Seed bank density ranged from 1980 to 6003 seeds/m2 on the borrow area and from 3202 to 4647 seeds/m2 on the Geum turf area. The Geum turf area had higher vegetation cover than the borrow area (87 vs. 25%) and higher numbers of species in the aboveground vegetation, seed rain, and seed bank. Relationships among the aboveground vegetation, seed rain, and seed bank were largely determined by the disturbance characteristics of the different sites and the life-history strategies of the dominant species. Medium-lived species, primarily grasses, with high production of small and compact seeds had colonized the borrow area. Despite establishment of other species, 35 years after disturbance the medium-lived species still dominated the aboveground vegetation, seed rain, and seed bank. Species abundances in the three different components were all highly correlated. In contrast, on the Geum turf area there were no correlations among the aboveground vegetation, seed rain, or seed bank. Long-lived forbs that produced low numbers of relatively large seeds dominated the aboveground vegetation and persisted on the area primarily in the vegetative state. The same medium-lived species that dominated the borrow area had the highest abundance in the seed rain on the Geum turf area and appeared to persist by colonizing small-scale disturbances caused by gopher burrowing. Short-lived species with small, long-lived seeds existed on the site primarily through a highly persistent seed bank. The relationships among the aboveground vegetation, seed rain, and seed bank on the Geum turf and borrow areas are compared with those observed for more temperate systems following disturbance. Key words: alpine, herb field, Geum turf, disturbance, vegetation cover, seed rain, seed bank, colonization, establishment, succession.
10
Shibuya, S., K. Kubota y M. Ohsawa. "Effects of small-scale management on biodiversity of an abandoned coppice forest in Japan: a case study on vegetation regeneration and ground beetle community". Web Ecology 8, n.º 1 (19 de noviembre de 2008): 116–24. http://dx.doi.org/10.5194/we-8-116-2008.
Texto completoResumen
Abstract. We studied the effects of small-scale vegetation disturbances on biodiversity in an abandoned coppice forest in central Japan during 2004–2006. We assessed biodiversity by examining vegetation regeneration and by changes in the diversity and abundance of ground beetles after experimental manipulations including tree felling, vegetation clearing, and litter removal. Our experimental design was dictated by the need of producing only small disturbances; therefore we could not replicate plots. Instead, we used a repeated measures approach during three years to document the consistency of experimental effects. We found that the diversity of regenerating vegetation increased dramatically due to recruitment of many new species after clearing ground vegetation. Tree cutting caused strong environmental changes and affected vegetation regeneration rate but not diversity. Tree cutting also significantly increased the diversity of ground beetle species, while litter removal affected the abundance of ground beetles. Our results suggest that a sound conservation practice shall combine tree cutting with ground vegetation clearing and litter removal. Besides, conservation of abandoned forests may be based on low-intensity labor, including tree cutting on restricted areas. Finally, ground beetles appeared to be surprisingly sensitive to vegetation disturbance on a restricted area and thus can be suggested for monitoring such small-scale-disturbance-based conservation practices.
11
Calmels, Fabrice, Duane G. Froese y Wendy R. Clavano. "Cryostratigraphic record of permafrost degradation and recovery following historic (1898–1992) surface disturbances in the Klondike region, central Yukon Territory1This article is one of a series of papers published in this CJES Special Issue on the theme of Fundamental and applied research on permafrost in Canada.2Yukon Geological Survey Contribution 008." Canadian Journal of Earth Sciences 49, n.º 8 (agosto de 2012): 938–52. http://dx.doi.org/10.1139/e2012-023.
Texto completoResumen
We present a detailed cryostratigraphic reconstruction of the degradation and recovery of near-surface permafrost in the southern Klondike goldfields, central Yukon Territory. Two ice-rich layers are recognized in near-surface permafrost and attributed to thermal impacts following vegetation disturbance. At an undisturbed forest site, the base of the modern active layer is stable. At an adjacent site, where a late twentieth century disturbance of surface vegetation and permafrost degradation occurred, there is evidence of recovery in the form of aggradation (upward shift) of the permafrost table following limited vegetation succession. Underlying both the undisturbed forest and the late twentieth century disturbance is an older thaw unconformity corresponding to a thaw depth of ∼2 m, likely associated with early twentieth century (gold rush era) impacts. Field and air photo surveys allow identification of the nature of the disturbances, while a chronology of the surface disturbance has been established using age estimates from tree rings, and the presence of tritium and post-bomb 14C from organic samples within aggradational ice. Collectively, these data underscore the importance of vegetation cover in maintaining ground temperatures in the discontinuous permafrost zone and suggest that, at least at the study site in recent decades, permafrost shows the potential to recover from disturbance in the modern climatic regime of the region.
12
Eldridge, David J. y Alan B. C. Kwok. "Soil disturbance by animals at varying spatial scales in a semi-arid Australian woodland". Rangeland Journal 30, n.º 3 (2008): 327. http://dx.doi.org/10.1071/rj08008.
Texto completoResumen
We studied soil disturbance by rabbits, echidnas, goannas, ants and termites at three different spatial scales across four vegetation communities (dense woodland, open woodland, shrubland, grassland) in semi-arid rangeland in western NSW. For analyses, bare and litter-covered surfaces (micro-scale) were nested within canopy and open patches (intermediate scale), which were nested within vegetation communities (landscape scale). Landscape-scale disturbances (rabbit warrens) were six and three times more abundant in open woodlands and shrublands, respectively, than in dense woodlands. Although individual warrens had a similar mass of excavated soil across all vegetation communities, in total, more soil was excavated in the grasslands than in the dense woodlands or shrublands. There were four times as many intermediate-sized disturbances (foraging pits and resting sites) under canopies than out in the open, and this was consistent across all vegetation communities. Echidna foraging pits and kangaroo resting sites dominated the canopy patches. Intermediate-sized disturbances scaled up to the landscape scale were marginally more abundant in the dense and open woodlands than in grasslands and shrublands. However, total mass of soil moved by all species did not differ among vegetation communities. The density of small-scale disturbances (ant nests, termite foraging galleries) did not differ at the landscape-, intermediate- or micro-scales. Our study documents the extent of animal activity in the semi-arid woodlands, and reinforces the notion that, as soil disturbance is scale-dependent, differences among species, habitats and communities will depend on the scale at which disturbances are examined.
13
Kutnar, Nagel y Kermavnar. "Effects of Disturbance on Understory Vegetation across Slovenian Forest Ecosystems". Forests 10, n.º 11 (19 de noviembre de 2019): 1048. http://dx.doi.org/10.3390/f10111048.
Texto completoResumen
The herbaceous understory represents a key component of forest biodiversity across temperate forests of Europe. Here, we quantified changes in the diversity and composition of the forest understory layer in representative Slovenian forest ecosystems between 2004/05 and 2014/15. In total, 60 plots were placed across 10 different managed forest types, ranging from lowland deciduous and mid-altitude mesic mixed forests to mountain conifer forests. This network is part of an international network of sites launched within the ICP Forests Programme aimed to assess the condition of forests in Europe. To examine how disturbance influenced understory dynamics, we estimated the disturbance impacts considering both natural and/or anthropogenic disturbances that cause significant damage to trees and to ground-surface layers, including ground-vegetation layers and upper-soil layers. Species richness across 10 sites (gamma diversity) significantly decreased from 272 to 243 species during the study period, while mean species richness per site did not significantly change. The mean value of site level Shannon diversity indices and evenness significantly increased. The cover of most common plant species increased during the monitoring period. The mean value of disturbance estimates per site increased from 0.8% in 2004/05 (ranging from 0% to 2.5%) to 16.3% in 2014/15 (ranging from 5.0% to 38.8%), which corresponded to a reduction in total vegetation cover, including tree-layer cover. More disturbed sites showed larger temporal changes in species composition compared to less disturbed sites, suggesting that forest disturbances caused understory compositional shifts during the study period. Rather than observing an increase in plant diversity due to disturbance, our results suggest a short-term decrease in species number, likely driven by replacement of more specialized species with common species.
14
Komba, Atupelye W., Teiji Watanabe, Masami Kaneko y Mohan Bahadur Chand. "Monitoring of Vegetation Disturbance around Protected Areas in Central Tanzania Using Landsat Time-Series Data". Remote Sensing 13, n.º 9 (5 de mayo de 2021): 1800. http://dx.doi.org/10.3390/rs13091800.
Texto completoResumen
Understanding vegetation disturbance around protected areas (PAs) is critical as it significantly affects the sustainable conservation of wildlife. However, there is a lack of analyses of consistent long-term data on vegetation disturbance. In this study, the LandTrendr algorithm and Google Earth Engine were used to access satellite data and explore the vegetation dynamics history across the Ruaha–Rungwa landscape, Tanzania. We characterized vegetation disturbance patterns and change attributes, including disturbance occurrence trends, rate, and severity, by using each pixel’s normalized burn ratio index time series. Between 2000 and 2019, 36% of the vegetation was significantly disturbed by anthropogenic activities. The results of this study show that the disturbance trends, severity, and patterns are highly variable and strongly depend on the management approaches implemented in the heterogeneous landscape: Ruaha National Park (RNP), Rungwa–Kizigo–Muhesi Game Reserves (RKMGR), and the surrounding zones. The disturbance rates and severity were pronounced and increased toward the edges of the western RKMGR. However, the disturbance in the areas surrounding the RNP was lower. The characterization of the vegetation disturbance over time provides spatial information that is necessary for policy makers, managers, and conservationists to understand the ongoing long-term changes in large PAs.
15
Saunders, Matthew, Sigrid Dengel, Pasi Kolari, Christine Moureaux, Leonardo Montagnani, Eric Ceschia, Nuria Altimir et al. "Importance of reporting ancillary site characteristics, and management and disturbance information at ICOS stations". International Agrophysics 32, n.º 4 (1 de diciembre de 2018): 457–69. http://dx.doi.org/10.1515/intag-2017-0040.
Texto completoResumen
Abstract There are many factors that influence ecosystem scale carbon, nitrogen and greenhouse gas dynamics, including the inherent heterogeneity of soils and vegetation, anthropogenic management interventions, and biotic and abiotic disturbance events. It is important therefore, to document the characteristics of the soils and vegetation and to accurately report all management activities, and disturbance events to aid the interpretation of collected data, and to determine whether the ecosystem either amplifies or mitigates climate change. This paper outlines the importance of assessing both the spatial and temporal variability of soils and vegetation and to report all management events, the import or export of C or N from the ecosystem, and the occurrence of biotic/abiotic disturbances at ecosystem stations of the Integrated Carbon Observation System, a pan-European research infrastructure.
16
Fleischer, Peter, Ladislav Holko, Slavomír Celer, Lucia Čekovská, Jozef Rozkošný, Peter Škoda, Lukáš Olejár y Peter Fleischer. "Carbon Balance and Streamflow at a Small Catchment Scale 10 Years after the Severe Natural Disturbance in the Tatra Mts, Slovakia". Water 12, n.º 10 (19 de octubre de 2020): 2917. http://dx.doi.org/10.3390/w12102917.
Texto completoResumen
Natural disturbances (windthrow, bark beetle, and fire) have reduced forest cover in the Tatra National Park (Slovakia) by 50% since the year 2004. We analyzed carbon fluxes and streamflow ten years after the forest destruction in three small catchments which differ in size, land cover, disturbance type and post-disturbance management. Point-wise CO2 fluxes were estimated by chamber methods for vegetation-dominated land-use types and extrapolated over the catchments using the site-specific regressions with environmental variables. Streamflow characteristics in the pre- and post-disturbance periods (water years of 1965–2004 and 2005–2014, respectively) were compared to identify changes in hydrological cycle initiated by the disturbances. Mature Norway spruce forest which was carbon neutral, turned to carbon source (330 ± 98 gC m−2 y−1) just one year after the wind disturbance. After ten years most of the windthrow sites acted as carbon sinks (from −341 ± 92.1 up to −463 ± 178 gC m−2 y−1). In contrast, forest stands strongly infested by bark beetles regenerated much slowly and on average emitted 495 ± 176 gC m−2 year−1. Ten years after the forest destruction, annual carbon balance in studied catchments was almost neutral in the least disturbed catchment. Carbon uptake notably exceeded its release in the most severely disturbed catchment (by windthrow and fire), where net ecosystem exchange (NEE) was −206 ± 115 gC m−2. The amount of sequestered carbon in studied catchments was driven by the extent of fast-growing successional vegetation cover (represented by the leaf area index LAI) rather than by the disturbance or vegetation types. Different post-disturbance management has not influenced the carbon balance yet. Streamflow characteristics did not indicate significant changes in the hydrological cycle. However, greater cumulative decadal runoff, different median monthly flows and low flows and the greater number of flow reversals in the in the first years after the windthrow in two severely affected catchments could be partially related to the influence of the disturbances.
17
White, Daniel J. y Peter A. Vesk. "Fire and legacy effects of logging on understorey assemblages in wet-sclerophyll forests". Australian Journal of Botany 67, n.º 4 (2019): 341. http://dx.doi.org/10.1071/bt18171.
Texto completoResumen
Wet sclerophyll forests of south-eastern Australia typically experience wildfire once or twice a century. However, disturbance regimes have changed drastically in recent decades due to clear-fell logging and altered fire regimes. To date, botanical research on disturbances in wet-forests has focussed on individual elements of disturbance regimes, such as intensity, at single points in time, largely neglecting past disturbance history. Studies of the impact of previous disturbance history on plant responses to successive disturbance events are important to our understanding of vegetation dynamics. Here we investigate the response of wet-forest understorey species to two important elements of disturbance regimes – timing and type – and trajectories of change in these vegetation communities. In surveys separated by 15 years over 128 sites, we recorded the frequency of occurrence of 21 understorey species from stands with disturbance histories ranging from 4 years post clear-fell logging to 150 years post wildfire. Approximately half our sites were burnt in the 2009 Black Saturday wildfires. This provided an opportunity to examine the effects of inter-fire interval and the legacy effects of clear-fell logging. Generalised linear mixed modelling showed that many of the species studied appear to be at risk of population decline as a result of clear-fell logging. Unlike wildfire, clear-fell logging led to changes in the understorey, having a long-lasting impact on the presence of key wet-forest taxa that rely on vegetative regeneration. These include large shade-bearing shrubs like Hedycarya angustifolia R.Cunn., Bedfordia arborescens Hochr. and Olearia argophylla (Labill.) Benth., which were resilient to recurrent wildfire but responded negatively to recent wildfire in sites with a history of clear-fell logging. Negative effects of a short inter-fire interval were limited to a few species.
18
Boon, M. A. y S. Tesfamichael. "DETERMINATION OF THE PRESENT VEGETATION STATE OF A WETLAND WITH UAV RGB IMAGERY". ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-3/W2 (15 de noviembre de 2017): 37–41. http://dx.doi.org/10.5194/isprs-archives-xlii-3-w2-37-2017.
Texto completoResumen
The compositional and structural characteristics of wetland vegetation play a vital role in the services that a wetland supplies. Apart from being important habitats, wetland vegetation also provide services such as flood attenuation and nutrient retention. South Africa is known to be a water scarce country. The protection and continuous monitoring of wetland ecosystems is therefore important. Factors such as site transformation and disturbance may completely change the vegetation of a wetland and the use of Unmanned Aerial Vehicle (UAV) imagery can play a valuable role in high-resolution monitoring and mapping. This study assessed if the use of UAV RGB imagery can enhance the determination of the present vegetation state of a wetland. The WET-Health level two (detailed on-site evaluation) methodology was followed for the vegetation assessment, where wetland health is a measure of the deviation of a wetland’s structure and function from its natural reference condition. The mapping of the disturbances classes was then undertaken using ultra-high resolution orthophotos, point clouds and digital surface models (DSM). The WET-Health vegetation module completed with the aid of the UAV products still indicates that the vegetation of the wetland is largely modified (“D” PES Category) and that the vegetation of the wetland will further deteriorate (change score). These results are the same as determined in the baseline study. However a higher impact (activities taking place within the wetland) score were determined. The assessment of various WET-Health vegetation indicators were significantly enhanced using the UAV imagery and derived products. The UAV products provided an accurate vantage point over the wetland and surroundings, and assisted to easily refine the assessment of the disturbance classes and disturbance units.
19
Tremont, RM y S. Mcintyre. "Natural Grassy Vegetation and Native Forbs in Temperate Australia: Structure, Dynamics and Life-Histories". Australian Journal of Botany 42, n.º 6 (1994): 641. http://dx.doi.org/10.1071/bt9940641.
Texto completoResumen
This paper describes aspects of the structure, floristics and dynamics of natural grassy vegetation in temperate Australia. The community structure of this vegetation type can be conceptualised using a matrix-interstitium model which may be useful in studies of the dynamics of forb populations and the role of disturbances in grassland management. Disturbance alters the balance between the matrix and interstitial components and is important for herbaceous communities as an agent in changes to, and losses of, native species. Life history characteristics conferring tolerance of disturbance upon native forbs are discussed, and the ruderal nature of the exotic component is suggested as a characteristic leading to the replacement of native forbs by exotic species, where substantial exogenous disturbance occurs. Despite the demonstrated importance of exogenous disturbances in influencing native species diversity and exotic invasions, there is still a poor understanding of the specific and interactive effects of various disturbances and the roles of particular plant traits in determining forb survival. Further research, utilising comparative or functional group approaches, is required to explain responses of natural grassy communities and native forbs. Such studies would provide opportunities for developing ecological theory and improving the management of natural grassy communities and their native forbs.
20
Ojha, Santosh K., Kozma Naka y Luben D. Dimov. "Assessment of Disturbances across Forest Inventory Plots in the Southeastern United States for the Period 1995–2018". Forest Science 66, n.º 2 (26 de noviembre de 2019): 242–55. http://dx.doi.org/10.1093/forsci/fxz072.
Texto completoResumen
Abstract Disturbances of varying frequency and intensity shape the species composition, stand structure, and functions of forests. This study assessed the frequency and distribution of disturbances caused by eight agents (insects, diseases, fire, animals, weather, other vegetation, human, and unknown) in the forests of the southeastern United States from 1995 to 2018. We used data from 88,722 inventory measurements of 33,531 plots from the USDA Forest Inventory and Analysis database to assess disturbance among different forest types and to different canopy strata. Disturbances were detected in approximately 14 percent of the plots, located mostly in pine-dominated forest types. Fire was the most frequent disturbance agent (occurring 6 percent of the time), followed by weather and animal agents. The agents that caused the highest mortality rate during the period for saplings were silvicultural treatments (8.6 percent), other vegetation (5.6 percent), and fire (4.4 percent), whereas for trees they were silvicultural treatments (9.8 percent), weather (1.9 percent) and insects (1.7 percent). The forest type that appeared to have been most affected by disturbances was longleaf–slash pine of the Coastal Plain. These results are useful for understanding the spatiotemporal distribution of disturbance events in different southeastern forest types and locations and for guiding forest management activities to mitigate potential impacts.
21
McDowell, Nate G., Craig D. Allen, Kristina Anderson-Teixeira, Brian H. Aukema, Ben Bond-Lamberty, Louise Chini, James S. Clark et al. "Pervasive shifts in forest dynamics in a changing world". Science 368, n.º 6494 (28 de mayo de 2020): eaaz9463. http://dx.doi.org/10.1126/science.aaz9463.
Texto completoResumen
Forest dynamics arise from the interplay of environmental drivers and disturbances with the demographic processes of recruitment, growth, and mortality, subsequently driving biomass and species composition. However, forest disturbances and subsequent recovery are shifting with global changes in climate and land use, altering these dynamics. Changes in environmental drivers, land use, and disturbance regimes are forcing forests toward younger, shorter stands. Rising carbon dioxide, acclimation, adaptation, and migration can influence these impacts. Recent developments in Earth system models support increasingly realistic simulations of vegetation dynamics. In parallel, emerging remote sensing datasets promise qualitatively new and more abundant data on the underlying processes and consequences for vegetation structure. When combined, these advances hold promise for improving the scientific understanding of changes in vegetation demographics and disturbances.
22
Dyderski, Marcin K. y Andrzej M. Jagodziński. "Context-Dependence of Urban Forest Vegetation Invasion Level and Alien Species’ Ecological Success". Forests 10, n.º 1 (3 de enero de 2019): 26. http://dx.doi.org/10.3390/f10010026.
Texto completoResumen
Research Highlights: Urban ecosystems are claimed to be more invaded than natural vegetation. Despite numerous studies, the patterns of alien species occurrence in urban forests are rarely linked to invasion ecology hypotheses. Background and Objectives: We assumed that patterns of invasion level (i.e., neophyte richness) and neophyte ecological success (cover) are context-dependent, i.e., depend on the type of vegetation, and that hypotheses connected with empty niche and biotic acceptance will have the strongest support in urban forests. We also tested biotic resistance, habitat filtering, disturbance, resource availability, and environmental heterogeneity hypotheses. Materials and Methods: Using a random forest algorithm, we tested the importance of factors related to invasion ecology hypotheses in a dataset of urban forest vegetation plots (n = 120). We studied seven types of forest plant communities occurring in Poznań (W Poland) and we assessed the vegetation’s taxonomic and functional composition. Results: We found that models of alien species richness and cover explained 28.5% and 35.0% of variance, respectively. Vegetation type was of the highest importance in both cases, suggesting that the occurrence of alien plant species is context-dependent. Resource availability and disturbance ecological indicator values were also of high importance. Conclusions: Our study supported resource availability and habitat filtering hypotheses as explanations of the level of invasion and ecological success of alien species in an urban forest, with partial support for the disturbance hypothesis. Our study revealed that predictors of invasion level are context-dependent, as patterns of alien species richness and cover differed among vegetation types. We highlight context-dependence of alien species invasion patterns in different vegetation types due to the habitat-forming role of dominant tree species and different availability of resources and disturbance levels, as well as different pools of native species. Thus, prevention and management of biological invasions in urban forests should account for forest vegetation type.
23
Goode, J. Davis, Jonathan S. Kleinman y Justin L. Hart. "Resilience of a Fire-Maintained Pinus palustris Woodland to Catastrophic Wind Disturbance: 10 Year Results". Forests 12, n.º 8 (7 de agosto de 2021): 1051. http://dx.doi.org/10.3390/f12081051.
Texto completoResumen
Increased interest in ecosystem recovery and resilience has been driven by concerns over global change-induced shifts in forest disturbance regimes. In frequent-fire forests, catastrophic wind disturbances modify vegetation-fuels-fire feedbacks, and these alterations may shift species composition and stand structure to alternative states relative to pre-disturbance conditions. We established permanent inventory plots in a catastrophically wind-disturbed and fire-maintained Pinus palustris woodland in the Alabama Fall Line Hills to examine ecosystem recovery and model the successional and developmental trajectory of the stand through age 50 years. We found that sapling height was best explained by species. Species with the greatest mean heights likely utilized different regeneration mechanisms. The simulation model projected that at age 50 years, the stand would transition to be mixedwood and dominated by Quercus species, Pinus taeda, and P. palustris. The projected successional pathway is likely a function of residual stems that survived the catastrophic wind disturbance and modification of vegetation-fuels-fire feedbacks. Although silvicultural interventions will be required for this system to exhibit pre-disturbance species composition and structure, we contend that the ecosystem was still resilient to the catastrophic disturbance because similar silvicultural treatments were required to create and maintain the P. palustris woodland prior to the disturbance event.
24
Mazzoleni, S., A. Esposito, R. Castaldo-Cobianchi y C. Blasi. "Bryophyte populations in Mediterranean environments. Relationships to vascular vegetation and disturbance patterns". Phytocoenologia 21, n.º 4 (19 de abril de 1993): 369–85. http://dx.doi.org/10.1127/phyto/21/1993/369.
Texto completo
25
Smith, Loren M. y John A. Kadlec. "The effects of disturbance on marsh seed banks". Canadian Journal of Botany 63, n.º 12 (1 de diciembre de 1985): 2133–37. http://dx.doi.org/10.1139/b85-301.
Texto completoResumen
Seed numbers and the species composition of seed banks (germinable seeds) from a marsh adjacent to the Great Salt Lake were compared among five vegetation types prior to a drawdown, during a drawdown, and prior to fire, after fire, and after restoration of normal water levels. Substrate samples were processed in the greenhouse under submersed and moist soil treatments to simulate the two germination conditions found in the field. After the fire, seed movement into the different vegetation types was also estimated. Numbers of germinable seeds were not depleted during the drawdown, possibly owing to increased salinity and the presence of standing vegetation. Fire had little effect on seed banks and subsequent seedling response. In general, seed banks were not affected by disturbance (e.g., burning, drawdown). The movement of seeds into the different vegetation types indicated that seed ingress could be important when one considers potential vegetation change. Seed banks of open water sites contained few germinable seeds when compared with Scirpus lacustris, S. maritimus, Distichlis spicata, and Typha spp. sites. Open water sites were devoid of vegetation and had few physical barriers, and seeds continued to move (air, water) across these areas until a barrier was reached, e.g., sites with vegetation.
26
Roberts, Mark R. "Response of the herbaceous layer to natural disturbance in North American forests". Canadian Journal of Botany 82, n.º 9 (1 de septiembre de 2004): 1273–83. http://dx.doi.org/10.1139/b04-091.
Texto completoResumen
Most work on the disturbance ecology of North American forests has focused on the tree canopy and woody understory, with little consideration of the herbaceous layer. Understanding how this species-rich and ecologically important layer responds to natural disturbances is needed as a guide for conservation. As a framework for this review, selected natural disturbances common to North American forests are evaluated in terms of a three-axis model of disturbance severity: percentage of tree canopy removed, percentage of understory vegetation removed, and percentage of forest floor and soil removed or disrupted. Eight factors, which control herbaceous-layer response, are linked to the three axes; these factors vary in dominance, depending on disturbance type and severity. The relative importances of different species' regeneration mechanisms also vary along severity gradients. The disturbance-severity model, along with the linked response factors and regeneration mechanisms, provide a framework for evaluating impacts of both natural and anthropogenic disturbances. Long-term studies of herbaceous-layer response to disturbance are needed, particularly mechanistic studies that focus on the relative importance of the eight factors controlling response. The conceptual model proposed herein needs to be tested across the full spectrum of severity levels. Finally, comparisons between natural and anthropogenic disturbances are needed.Key words: disturbance, forests, herbaceous layer, life-history characteristics, succession, understory.
27
Steyer, Gregory D., Brady R. Couvillion y John A. Barras. "Monitoring Vegetation Response to Episodic Disturbance Events by using Multitemporal Vegetation Indices". Journal of Coastal Research 63 (abril de 2013): 118–30. http://dx.doi.org/10.2112/si63-011.1.
Texto completo
28
Konôpka, Bohdan, Jozef Pajtík, František Máliš, Vladimír Šebeň y Miriam Maľová. "Carbon stock in aboveground biomass of vegetation at the High Tatra Mts. twelve years after disturbance". Central European Forestry Journal 63, n.º 2-3 (27 de junio de 2017): 142–51. http://dx.doi.org/10.1515/forj-2017-0007.
Texto completoResumen
AbstractThe paper focused on the estimation of aboveground biomass and its carbon stock in the vegetation cover on the territory of the High Tatras twelve years after a large-scale wind disturbance. Besides biomass quantification of main plant groups (i.e. trees and ground vegetation) we considered plant components with special regard to carbon rotation rate. The measurements were performed on two transects each containing 25 plots sized 4 × 4 m. Height and stem diameter of all trees on the plots were measured and used for biomass estimation. To quantify the biomass of ground vegetation, six subplots sized 20 × 20 cm were systematically placed on each plot and the aboveground biomass was harvested. The plant material was subjected to chemical analyses to quantify its carbon concentration. The study showed that while the wind disturbance caused dramatic decrease of carbon stock, young post-disturbance stands with abundant ground vegetation, represented large carbon flux via litter fall. Twelve years after the wind disturbance, the trees contributed to carbon stock more than the ground vegetation. However, the opposite situation was recorded for the carbon flux to litter that was related to the dominance of annual plants in the above-ground biomass of ground vegetation. The carbon stock in the biomass of young trees and ground vegetation represented about 8,000 kg per ha. The young stands manifested a dynamic growth, specifically the aboveground biomass increased annually by one third. The results confirmed different carbon regimes in the former old (pre-disturbance) and sparse young (post-disturbance) stands.
29
DeRose, R. Justin y James N. Long. "Drought-driven disturbance history characterizes a southern Rocky Mountain subalpine forest". Canadian Journal of Forest Research 42, n.º 9 (septiembre de 2012): 1649–60. http://dx.doi.org/10.1139/x2012-102.
Texto completoResumen
The view that subalpine forest vegetation dynamics in western North America are “driven” by a particular disturbance type (i.e., fire) has shaped our understanding of their disturbance regimes. In the wake of a recent (1990s) landscape-extent spruce beetle ( Dendroctonus rufipennis Kirby) outbreak in the southern Rocky Mountains, we re-examined the temporal continuity in disturbance types and interactions and the possible role of drought on their occurrence by reconstructing antecedent disturbances for 11 sites across the Markagunt Plateau, southern Utah, USA. Multiple consistent lines of evidence suggested that historic fires were the primary antecedent disturbance, while relatively minor, stand-specific spruce beetle activity occurred later in stand development but prior to the recent outbreak. Unlike the recent outbreak, antecedent fires were spatially and temporally asynchronous over the period examined (~1600–2000). Reconstructed fire events primarily occurred during periods of prolonged drought. Similarly, historic spruce beetle activity, indicated by species-specific tree-ring release, and timing of Engelmann spruce ( Picea engelmannii Parry ex Engelm.) death dates from the recent outbreak were related to drought conditions. Vegetation dynamics on this landscape were strongly driven by historic fires and the recent spruce beetle outbreak, and drought conditions likely influenced the occurrence of both disturbance types.
30
Chew, Jimmie D., Christine Stalling y Kirk Moeller. "Integrating Knowledge for Simulating Vegetation Change at Landscape Scales". Western Journal of Applied Forestry 19, n.º 2 (1 de abril de 2004): 102–8. http://dx.doi.org/10.1093/wjaf/19.2.102.
Texto completoResumen
Abstract Managers of public lands are increasingly faced with making planning decisions for dynamic landscapes with conflicting objectives. A modeling system has been designed to serve as a decision support system to help managers and resource specialists integrate the available knowledge of vegetation change and disturbance processes, and quantify concepts that are often difficult to interpret for specific landscapes. The system is named SIMPPLLE, an acronym taken from “<bi>SIM</bi>ulating vegetation <bi>P</bi>atterns and <bi>P</bi>rocesses at Landscape scaLEs.” SIMPPLLE can be used to help define and evaluate future conditions at landscape scales, to identify areas that are more prone to disturbances over a given time frame, to identify the options for influencing these disturbance processes, and to help design and evaluate different strategies for achieving desired future conditions. The emphasis in this article is to give an overview of the design of the system, the types of knowledge integrated, and the type of output produced. The initial validation work discussed indicates that the approach used for capturing and integrating process knowledge in SIMPPLLE does predict realistic results at landscape scales. SIMPPLLE provides managers a tool to integrate and interpret concepts of desired future conditions, range of variability, and the interaction between vegetation patterns and disturbance processes. SIMPPLLE provides a way to help evaluate proposed management scenarios within a future that includes stochastic processes. West. J. Appl. For. 19(2):102–108.
31
Hailemariam, Mesfin Belete y Tamru Demsis Temam. "Pattern of Plant Community Distribution along the Elevational Gradient and Anthropogenic Disturbance in Gole Forest, Ethiopia". International Journal of Ecology 2020 (3 de diciembre de 2020): 1–9. http://dx.doi.org/10.1155/2020/6536374.
Texto completoResumen
Vegetation-environment relationships are usually studied along elevational gradient. The patterns of plant community distribution in Gole forest, Ethiopia, were studied along elevational gradient and disturbances. Disturbances were recorded following the elevational gradient. For vegetation data collection, 62 sample plots of size 20 × 20 m were established along an elevational gradient (2728–3480 m.a.s.l). Data on species composition and environmental variables were measured and recorded in each plot. The elevation of each sample plot was measured using Garmin GPS. Anthropogenic disturbances in each plot were estimated using the following scales: 0 = no disturbance, 1 = slightly disturbed, 2 = moderately disturbed, and 3 = highly disturbed. R statistical package was used for cluster and ordination analysis. Boxplots and analysis of variance were used to assess the relationships between plant communities and environmental variables. Sorensen’s similarity coefficient was used to detect similarities and dissimilarities among communities. A total of 114 plant species belonging to 57 families and 94 genera were identified. Five plant community types were identified using agglomerative hierarchical cluster analysis. Every plant community had differences in composition and environmental variables. The variation in plant community distributions was significantly related to elevation and disturbance. Plant community distribution was negatively correlated with elevation ( P < 0.05 ) and also with disturbance ( P < 0.05 ). Sorensen’s similarity index showed that there was a difference in the distribution of plant species composition among the communities. The difference in plant community distribution of Gole forest was significantly related to elevation. Disturbances also have a considerable influence on the plant communities and mitigation of disturbance should be the main measure that needs to be taken into account in conservation planning in the study area.
32
Khatancharoen, Chulabush, Satoshi Tsuyuki, Semyon V. Bryanin, Konosuke Sugiura, Tatsuyuki Seino, Viktor V. Lisovsky, Irina G. Borisova y Naoya Wada. "Long-Time Interval Satellite Image Analysis on Forest-Cover Changes and Disturbances around Protected Area, Zeya State Nature Reserve, in the Russian Far East". Remote Sensing 13, n.º 7 (27 de marzo de 2021): 1285. http://dx.doi.org/10.3390/rs13071285.
Texto completoResumen
Boreal forest areas in the Russian Far East contained very large intact forests. This particular area is considered one of the most productive and diverse forests in the boreal biome of the world, and it is also home to many endangered species. Zeya State Nature Reserve is located at the southern margin of the boreal forest area in the Russian Far East and has rich fauna and flora. However, the forest in the region faced large-scale forest fires and clearcutting for timber recently. The information of disturbances is rarely understood. This study aimed to explore the effects of disturbance and forest dynamics around the reserve. Our study used two-year overlaid Landsat images from Landsat 5 Thematic Mapper (TM) and 8 Operational Land Imager (OLI), to generate forest-cover-change maps of 1988–1999, 1999–2010, and 2010–2016. In this paper, we analyze the direction of forest successional stages, to demonstrate the effectiveness of this protected area in terms of preventing human-based deforestation on the vegetation indices. The vegetation indices included the normalized burn ratio (NBR), the normalized difference vegetation index (NDVI), and the normalized difference water index (NDWI). The study provided information on the pattern of forest-cover change and disturbance area around the reserve. The NDWI was used to differentiate between water and non-water areas. The mean values of NBR and NDVI were calculated and determine the forest successional stages between burn, vegetation recovery, grass, mixed forest, oak forest, and birch and larch forest. The accuracy was assessed by using field measurements, field photos, and high-resolution images as references. Overall, our classification results have high accuracy for all three periods. The most disturbed area occurred during 2010–2016. The reserve was highly protected, with no human-disturbance activity. However, large areas from fire disturbance were found (137 km2) during 1999–2010. The findings also show a large area of disturbance, mostly located outside of the reserve. Mixed disturbance increased to almost 50 km2 during 2010–2016, in the buffer zone and outside of the reserve. We recommend future works to apply our methods to other ecosystems, to compare the forest dynamics and disturbance inside and outside the protected area.
33
Khodaee, Mahsa, Taehee Hwang, JiHyun Kim, Steven P. Norman, Scott M. Robeson y Conghe Song. "Monitoring Forest Infestation and Fire Disturbance in the Southern Appalachian Using a Time Series Analysis of Landsat Imagery". Remote Sensing 12, n.º 15 (28 de julio de 2020): 2412. http://dx.doi.org/10.3390/rs12152412.
Texto completoResumen
The southern Appalachian forests have been threatened by several large-scale disturbances, such as wildfire and infestation, which alter the forest ecosystem structures and functions. Hemlock Woolly Adelgid (Adelges tsugae Annand, HWA) is a non-native pest that causes widespread foliar damage and eventual mortality, resulting in irreversible tree decline in eastern (Tsuga canadensis) and Carolina (T. caroliniana) hemlocks throughout the eastern United States. It is important to monitor the extent and severity of these disturbances over space and time to better understand their implications in the biogeochemical cycles of forest landscapes. Using all available Landsat images, we investigate and compare the performance of Tasseled Cap Transformation (TCT)-based indices, Normalized Difference Vegetation Index (NDVI), Enhanced Vegetation Index (EVI), and Disturbance Index (DI) in capturing the spectral-temporal trajectory of both abrupt and gradual forest disturbances (e.g., fire and hemlock decline). For each Landsat pixel, the temporal trajectories of these indices were fitted into a time series model, separating the inter-annual disturbance patterns (low frequency) and seasonal phenology (high frequency) signals. We estimated the temporal dynamics of disturbances based on the residuals between the observed and predicted values of the model, investigated the performance of all the indices in capturing the hemlock decline intensity, and further validated the results with the number of individual dead hemlocks identified from high-resolution aerial images. Our results suggested that the overall performance of NDVI, followed by TCT wetness, was most accurate in detecting both the disturbance timing and hemlock decline intensity, explaining over 90% of the variability in the number of dead hemlocks. Despite the overall good performance of TCT wetness in characterizing the disturbance regime, our analysis showed that this index has some limitations in characterizing disturbances due to its recovery patterns following infestation.
34
Mladenoff, David J. "The relationship of the soil seed bank and understory vegetation in old-growth northern hardwood–hemlock treefall gaps". Canadian Journal of Botany 68, n.º 12 (1 de diciembre de 1990): 2714–21. http://dx.doi.org/10.1139/b90-344.
Texto completoResumen
In mature northern hardwood forests, small treefall gaps constitute an important mode of compositional and structural change within the long return time of larger catastrophic disturbances. The soil seed bank and patterns in vegetation layers are described in this disturbance regime context. In these small treefall gaps, herbaceous and woody vegetation species present are similar to those of forest understory plots, differing primarily in abundance. Seed bank communities are compositionally more similar among gaps than forest understory plots, but vegetation similarity is equal among forest plots and among gaps. Seed bank-vegetation similarity is greater among forest plots than in gaps. Seed bank strategies differ among the plant species characteristic of the differing forest layers. Dominant canopy tree species (Acer saccharum, Tsuga canadensis, Betula alleghaniensis) are not an important component of the seed bank. Bird-dispersed shrub and herbaceous species and ant-dispersed herbs are important in the seed bank, especially in gaps. In particular, based on gap seed bank response, it appears that understory shrub abundance and pattern within the forest change with the time since large-scale disturbance, in accordance with species adaptations to the size and increase in number of small treefalls in the mature forest. These species patterns may relate to the patchy nature of resource availability that develops, especially that of nitrogen, which is controlled by the canopy species–gap mosaic. Key words: treefall gaps, soil seed bank, disturbance, northern hardwoods, old growth, succession, shrubs.
35
Xiao, Wu, Xinyu Deng, Tingting He y Wenqi Chen. "Mapping Annual Land Disturbance and Reclamation in a Surface Coal Mining Region Using Google Earth Engine and the LandTrendr Algorithm: A Case Study of the Shengli Coalfield in Inner Mongolia, China". Remote Sensing 12, n.º 10 (18 de mayo de 2020): 1612. http://dx.doi.org/10.3390/rs12101612.
Texto completoResumen
The development and utilization of mining resources are basic requirements for social and economic development. Both open-pit mining and underground mining have impacts on land, ecology, and the environment. Of these, open-pit mining is considered to have the greatest impact due to the drastic changes wrought on the original landform and the disturbance to vegetation. As awareness of environmental protection has grown, land reclamation has been included in the mining process. In this study, we used the Shengli Coalfield in the eastern steppe region of Inner Mongolia to demonstrate a mining and reclamation monitoring process. We combined the Google Earth Engine platform with time series Landsat images and the LandTrendr algorithm to identify and monitor mining disturbances to grassland and land reclamation in open-pit mining areas of the coalfield between 2003 and 2019. Pixel-based trajectories were used to reconstruct the temporal evolution of vegetation, and sequential Landsat archive data were used to achieve accurate measures of disturbances to vegetation. The results show that: (1) the proposed method can be used to determine the years in which vegetation disturbance and recovery occurred with accuracies of 86.53% and 78.57%, respectively; (2) mining in the Shengli mining area resulted in the conversion of 89.98 km2 of land from grassland, water, etc., to barren earth, and only 23.54 km2 was reclaimed, for a reclamation rate of 26.16%; and (3) the method proposed in this paper can achieve fast, efficient identification of surface mining land disturbances and reclamation, and has the potential to be applied to other similar areas.
36
Shriver, Robert K. y Thomas A. Minckley. "Late-Holocene response of limber pine (Pinus flexilis) forests to fire disturbance in the Pine Forest Range, Nevada, USA". Quaternary Research 78, n.º 3 (20 de agosto de 2012): 465–73. http://dx.doi.org/10.1016/j.yqres.2012.07.010.
Texto completoResumen
AbstractDespite growing concerns that ecological stressors (fire, insect and pathogen outbreaks) may force vegetation change, few studies have attempted to use paleoecological data to understand small-scale interactions between disturbance and vegetation. Using charcoal and pollen data, we infer past fire episodes and subsequent vegetation responses for a limber pine (Pinus flexilis) forest in northwestern Nevada, USA, to determine local vegetation recovery from disturbance. Using superimposed epoch analysis we examined average-vegetation and individual-taxon responses to eight randomly selected fire events over the past 4.0 ka. Pollen evidence shows that on average fires produce a weak response of declining Pinus while other taxa including Artemisia and Poaceae increase directly after fire episodes. Within 30 yr of a disturbance, pollen data indicate ecosystem recovery to pre-fire composition, consistent with modern studies of fire recovery of limber pine forests. Similar to short-term changes of pollen abundance, long-term vegetation responses indicate Pinus abundance weakly declining and Artemisia increasing when fire episodes are frequent. However, despite fire-episode frequencies varying between 75 and 250 yr, the overall vegetation structure has remained relatively stable over the past 4.0 ka. Our study contributes to the limited information on the disturbance ecology of isolated, subalpine forests in the intermountain West.
37
Chaves Cardoso, Jéssica, Philip J. Burton y Che M. Elkin. "A Disturbance Ecology Perspective on Silvicultural Site Preparation". Forests 11, n.º 12 (28 de noviembre de 2020): 1278. http://dx.doi.org/10.3390/f11121278.
Texto completoResumen
Silvicultural site preparation methods are used as planned disturbances for counteracting soil and vegetation constraints, as well as facilitating successful tree regeneration and growth. Understanding the possible effects of silvicultural site preparation on the ecosystem and evaluating site preparation as an ecological disturbance can help guide the selection and application of site preparation techniques for forest management goals. This review evaluates silvicultural site preparation techniques that are commonly used in boreal mixedwood ecosystems as agents of ecological disturbance by comparing the effects of each technique on the area disturbed and the degree of biomass modification, and then ordering them along a disturbance severity gradient. With a strong emphasis on the numerical estimation of the spatial footprint of different disturbances, broadcast burning typically has the highest disturbance severity, followed in order by broadcast herbicide use, mixing, plowing, disc trenching, mounding, scalping, and inverting. The evaluation of disturbance severity of various silvicultural site preparation techniques while using the proposed framework is feasible, in which quantitative assessments of area disturbed and biomass modification could be collected and assessed in most managed forests.
38
Duhl, T. R., D. Helmig y A. Guenther. "Sesquiterpene emissions from vegetation: a review". Biogeosciences 5, n.º 3 (14 de mayo de 2008): 761–77. http://dx.doi.org/10.5194/bg-5-761-2008.
Texto completoResumen
Abstract. This literature review summarizes the environmental controls governing biogenic sesquiterpene (SQT) emissions and presents a compendium of numerous SQT-emitting plant species as well as the quantities and ratios of SQT species they have been observed to emit. The results of many enclosure-based studies indicate that temporal SQT emission variations appear to be dominated mainly by ambient temperatures although other factors contribute (e.g., seasonal variations). This implies that SQT emissions have increased significance at certain times of the year, especially in late spring to mid-summer. The strong temperature dependency of SQT emissions also creates the distinct possibility of increasing SQT emissions in a warmer climate. Disturbances to vegetation (from herbivores and possibly violent weather events) are clearly also important in controlling short-term SQT emissions bursts, though the relative contribution of disturbance-induced emissions is not known. Based on the biogenic SQT emissions studies reviewed here, SQT emission rates among numerous species have been observed to cover a wide range of values, and exhibit substantial variability between individuals and across species, as well as at different environmental and phenological states. These emission rates span several orders of magnitude (10s–1000s of ng gDW-1 h−1). Many of the higher rates were reported by early SQT studies, which may have included artificially-elevated SQT emission rates due to higher-than-ambient enclosure temperatures and disturbances to enclosed vegetation prior to and during sample collection. When predicting landscape-level SQT fluxes, modelers must consider the numerous sources of variability driving observed SQT emissions. Characterizations of landscape and global SQT fluxes are highly uncertain given differences and uncertainties in experimental protocols and measurements, the high variability in observed emission rates from different species, the selection of species that have been studied so far, and ambiguities regarding controls over emissions. This underscores the need for standardized experimental protocols, better characterization of disturbance-induced emissions, screening of dominant plant species, and the collection of multiple replicates from several individuals within a given species or genus as well as a better understanding of seasonal dependencies of SQT emissions in order to improve the representation of SQT emission rates.
39
Duhl, T. R., D. Helmig y A. Guenther. "Sesquiterpene emissions from vegetation: a review". Biogeosciences Discussions 4, n.º 6 (6 de noviembre de 2007): 3987–4023. http://dx.doi.org/10.5194/bgd-4-3987-2007.
Texto completoResumen
Abstract. This literature review summarizes the environmental controls governing biogenic sesquiterpene (SQT) emissions and presents a compendium of numerous SQT-emitting plant species as well as the quantities and ratios of SQT species they have been observed to emit. The results of many enclosure-based studies indicate that temporal SQT emission variations appear to be dominated mainly by ambient temperatures although other factors contribute (e.g. seasonal variations). This implies that SQT emissions have increased significance at certain times of the year, especially in late spring to mid-summer. The strong temperature dependency of SQT emissions also creates the distinct possibility of increasing SQT emissions in a warmer climate. Disturbances to vegetation (from herbivores and possibly violent weather events) are clearly also important in controlling short-term SQT emissions bursts, though the relative contribution of disturbance-induced emissions is not known. Based on the biogenic SQT emission studies reviewed here, SQT emission rates among numerous species have been observed to cover a wide range of values, and exhibit substantial variability between individuals and across species, as well as at different environmental and phenological states. These emission rates span several orders of magnitude (10s–1000s of ng gDW−1 h−1). Many of the higher rates were reported by early SQT studies, which may have included artificially-elevated SQT emission rates due to higher-than-ambient enclosure temperatures and disturbances to enclosed vegetation prior to and during sample collection. When predicting landscape-level SQT fluxes, modelers must consider the numerous sources of variability driving observed SQT emissions. Characterizations of landscape and global SQT fluxes are highly uncertain given differences and uncertainties in experimental protocols and measurements, the high variability in observed emission rates from different species, the selection of species that have been studied so far, and ambiguities regarding controls over emissions. This underscores the need for standardized experimental protocols, better characterization of disturbance-induced emissions, screening of dominant plant species, and the collection of multiple replicates from several individuals within a given species or genus as well as a better understanding of seasonal dependencies of SQT emissions in order to improve the representation of SQT emission rates.
40
Zampella, Robert A. y Kim J. Laidig. "Effect of Watershed Disturbance on Pinelands Stream Vegetation". Journal of the Torrey Botanical Society 124, n.º 1 (enero de 1997): 52. http://dx.doi.org/10.2307/2996598.
Texto completo
41
Wang, Jian Cheng, Jian Cai Chi y Bo Rong Pan. "Effects of Human Disturbance on Mountain Vegetation Communities". Vegetos- An International Journal of Plant Research 28, n.º 4 (2015): 194. http://dx.doi.org/10.5958/2229-4473.2015.00104.4.
Texto completo
42
Gibson, David J. "Effects of Animal Disturbance on Tallgrass Prairie Vegetation". American Midland Naturalist 121, n.º 1 (enero de 1989): 144. http://dx.doi.org/10.2307/2425665.
Texto completo
43
Yeakley, J. Alan, David C. Coleman, Bruce L. Haines, Brian D. Kloeppel, Judy L. Meyer, Wayne T. Swank, Barry W. Argo, James M. Deal y Sharon F. Taylor. "Hillslope Nutrient Dynamics Following Upland Riparian Vegetation Disturbance". Ecosystems 6, n.º 2 (1 de marzo de 2003): 154–67. http://dx.doi.org/10.1007/s10021-002-0116-6.
Texto completo
44
Stenhouse, Renae N. "Assessing Disturbance and Vegetation Condition in Urban Bushlands". Australasian Journal of Environmental Management 12, n.º 1 (enero de 2005): 16–26. http://dx.doi.org/10.1080/14486563.2005.10648630.
Texto completo
45
Overpeck, Jonathan T., David Rind y Richard Goldberg. "Climate-induced changes in forest disturbance and vegetation". Nature 343, n.º 6253 (enero de 1990): 51–53. http://dx.doi.org/10.1038/343051a0.
Texto completo
46
Belov, A. V. y L. P. Sokolova. "PROBLEMS IN THE CARTOGRAPHIC STUDY OF VEGETATION DISTURBANCE". Mapping Sciences and Remote Sensing 37, n.º 2 (abril de 2000): 137–43. http://dx.doi.org/10.1080/07493878.2000.10642141.
Texto completo
47
Solon, J. "Anthropogenic disturbance and vegetation diversity in agricultural landscapes". Landscape and Urban Planning 31, n.º 1-3 (febrero de 1995): 171–80. http://dx.doi.org/10.1016/0169-2046(94)01043-8.
Texto completo
48
Utaile, Yonas U., Kenny Helsen, Seyoum G. Aydagnehum, Bart Muys, Simon C. Shibru y Olivier Honnay. "Typology of the woody plant communities of the Ethiopian Nech Sar National Park and an assessment of vegetation-environment relations and human disturbance impacts". Plant Ecology and Evolution 153, n.º 1 (26 de marzo de 2020): 33–44. http://dx.doi.org/10.5091/plecevo.2020.1698.
Texto completoResumen
Background and aims – Deforestation and forest degradation have hugely affected the Southern Ethiopian Rift Valley, jeopardizing biodiversity conservation and ecosystem service provisioning. Quantifying the impacts of human activities on the remaining woody plant communities and recognizing vegetation–environment relationships provide the basis for targeted conservation and rehabilitation.Material and methods – The study was performed in the Nech Sar National Park (NSNP). Based on a large systematic vegetation survey of 104 plots, we quantified the woody vegetation composition, and we provided a vegetation classification based on Non Metric Multidimensional Scaling, cluster analysis and indicator species analysis. Furthermore, we evaluated vegetation – environment relationships and the effects of human disturbance on community composition and woody plant species richness and diversity.Key results – Our analyses revealed three very distinct woody vegetation types (Acacia mellifera-Combretum aculeatum; Lecaniodiscus fraxinifolius-Deinbollia kilimandscharica and Acacia polyacantha-Ficus sycomorus) which were significantly differentiated by soil pH, electrical conductivity, available soil phosphorus and organic matter, and by elevation. Human disturbance, as quantified by a compound Human Disturbance Index (HDI) significantly affected community composition, species richness and diversity, and was significantly positively correlated with species richness and diversity. The latter is likely due to intermediate levels of disturbance and encroachment of disturbance affiliated shrubs such as Dichrostachys cinerea, Lantana camara, and Acalypha fruticosa. Furthermore, the demographic structure of key woody species such as Acacia polyacantha, Acacia tortilis, Balanites aegyptiaca, Diospyros abyssinica, Lecaniodiscus fraxinifolius and Terminalia brownii, showed impacts of human disturbance.Conclusion – Our results provide a baseline for further conservation actions in the NSNP which should be differentially targeted on the different plant community types. Overall, human disturbance seems not to have resulted yet in species richness declines, although it has started to affect the integrity of the delineated vegetation types and resulted in small scale succession.
49
Weerakoon, Gothamie, Patricia Wolseley, Susan Will-Wolf y Chandrani Wijeyaratne. "Corticolous lichen species as indicators of disturbed/undisturbed vegetation types in the central mountains of Sri Lanka". Lichenologist 52, n.º 3 (mayo de 2020): 233–45. http://dx.doi.org/10.1017/s0024282920000109.
Texto completoResumen
AbstractCorticolous lichens in the central mountains of Sri Lanka differ with vegetation type, disturbance and climate. All growth forms of lichens were studied in 42 plots (six plots × seven vegetation types), yielding 124 species. Lichen species diversity varied with number of tree species per plot (correlations) and differed with disturbance group, vegetation type and climate zone (general linear models). Lichen community composition (estimated cover of 74 species each at ≥ 3 plots) varied along two ordination gradients secondarily correlated with disturbance (nonmetric multidimensional scaling, NMS). Undisturbed and disturbed plots (mostly grouped by vegetation type) were divided along NMS axis 1, correlating with distance to undisturbed forest. Longest-disturbed plots differed from all others along NMS axis 2 and were correlated with canopy cover. Climate was weakly reflected on the ordination as the proximity of two plot clusters in montane vegetation types. Indicator species analyses (ISA) of lichen cover by plot identified 60 strong indicator species (indicator value ≥ 50%, P < 0.015). Fifty-seven species were indicators for individual vegetation types (28 of them for undisturbed types); three were for a disturbance group only; 11 were also for a disturbance group or climate zone. Most species strongly driving ordination patterns were also ISA indicators. Most lichens were crustose (39, with 24 in the Graphidaceae). Each vegetation type had at least one indicator with trentepohliod algae (increasing for undisturbed plots) and one with chlorococcoid algae. Two visually distinct indicator species, three genera and two multi-genus groups will be useful to parataxonomists in forest evaluation.
50
Máliš, František, Bohdan Konôpka, Vladimír Šebeň, Jozef Pajtík y Katarína Merganičová. "Short-Term Dynamics of Vegetation Diversity and Aboveground Biomass of Picea abies (L.) H. Karst. Forests after Heavy Windstorm Disturbance". Forests 12, n.º 1 (17 de enero de 2021): 97. http://dx.doi.org/10.3390/f12010097.
Texto completoResumen
Although forest disturbances have become more frequent and severe due to ongoing climate change, our understanding of post-disturbance development of vegetation and tree–herb layer interactions remains limited. An extreme windstorm, which occurred on 19 November 2004, destroyed Picea abies (L.) H. Karst dominated forests in the High Tatra Mts. Here, we studied short-term changes in diversity, species composition, and aboveground biomass of trees and herb layer vegetation, including mutual relationships that elucidate tree–herb interactions during post-disturbance succession. Assessment of species composition and tree biomass measurements were performed at 50 sample plots (4 × 4 m) along two transects 12, 14, and 16 years after the forest destruction. Heights and stem base diameters of about 730 trees were measured and subsequently used for the calculation of aboveground tree biomass using species-specific allometric relationships. Aboveground biomass of herb layer was quantified at 300 subplots (20 × 20 cm) by destructive sampling. Species richness and spatial vegetation heterogeneity did not significantly change, and species composition exhibited small changes in accordance with expected successional trajectories. While aboveground tree biomass increased by about 190%, biomass of annual herb shoots decreased by about 68% and biomass of perennial herb shoots was stable during the studied period. The contribution of trees to total aboveground biomass increased from 83% to 97%. After 16 years of forest stands recovery, tree biomass represented approximately 13% of forest biomass before the disturbance. Herb layer biomass, particularly the biomass of annual herb shoots, was more closely related to tree cover than to tree biomass and its decline could be assigned to gradual tree growth. Our study provides clear evidence that short-term successional processes in post-disturbance vegetation are much better detectable by biomass than by diversity or compositional measures and emphasized the importance of light conditions in tree–herb competitive interactions.