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1
Soterroni, Aline C., Fernando M. Ramos, Aline Mosnier, Joseph Fargione, Pedro R. Andrade, Leandro Baumgarten, Johannes Pirker et al. "Expanding the Soy Moratorium to Brazil’s Cerrado". Science Advances 5, n. 7 (luglio 2019): eaav7336. http://dx.doi.org/10.1126/sciadv.aav7336.
Testo completoAbstract (sommario):
The Cerrado biome in Brazil is a tropical savanna and an important global biodiversity hot spot. Today, only a fraction of its original area remains undisturbed, and this habitat is at risk of conversion to agriculture, especially to soybeans. Here, we present the first quantitative analysis of expanding the Soy Moratorium (SoyM) from the Brazilian Amazon to the Cerrado biome. The SoyM expansion to the Cerrado would prevent the direct conversion of 3.6 million ha of native vegetation to soybeans by 2050. Nationally, this would require a reduction in soybean area of approximately 2%. Relative risk of future native vegetation conversion for soybeans would be driven by the Brazilian domestic market, China, and the European Union. We conclude that, to preserve the Cerrado’s biodiversity and ecosystem services, urgent action is required, including a zero native vegetation conversion agreement such as the SoyM.
2
ACOSTA, ROXANA, CARMEN GUZMÁN-CORNEJO, FLOR ANGÉLICA QUIÑONEZ CISNEROS, ANGÉLICA ANNAY TORRES QUIÑONEZ e JESÚS A. FERNÁNDEZ. "New records of ectoparasites for Mexico and their prevalence in the montane shrew Sorex monticolus (Eulipotyphla: Soricidae) at Cerro del Mohinora, Sierra Madre Occidental of Chihuahua, Mexico". Zootaxa 4809, n. 2 (7 luglio 2020): 393–96. http://dx.doi.org/10.11646/zootaxa.4809.2.11.
Testo completoAbstract (sommario):
The Flora and Fauna Protection Area (Área de Protección de Flora y Fauna—ÁPFF) Cerro del Mohinora, is the highest mountain in northern Mexico, reaching an elevation of 3,300 meters. It constitutes one of the last high-elevation islands of alpine and subalpine vegetation known in the Sierra Madre Occidental, in the extreme southwestern part of Chihuahua. The ÁPFF Cerro del Mohinora is located near the state border and limits with Durango and Sinaloa. This type of ecosystem located at high altitudes is in danger of disappearing since only 1% or less of its original extension remains; it is considered a refuge for species with boreal affinities (McDonald et al. 2011).
3
Cadena-Ortiz, Héctor, Santiago Varela, Daniela Bahamonde-Vinueza, Juan F. Freile e Elisa Bonaccorso. "Birds of Bosque Protector Jerusalem, Guayllabamba Valley, Ecuador". Check List 11, n. 5 (16 ottobre 2015): 1770. http://dx.doi.org/10.15560/11.5.1770.
Testo completoAbstract (sommario):
The Ecuadorian inter-Andean dry valleys are highly affected by human intervention. Currently, less than 5% of the original vegetation cover of these valleys remains on creeks and hillsides. Bosque Protector Jerusalem (1,110 ha), in the upper Guayllabamba River valley, protects the largest remnants of inter-Andean dry forest in Ecuador. Here, we present data derived from two recent studies (from 2009 to 2013), as well as information collected by other authors in previous studies, between the years 2002 and 2009. We present a unified list of 75 species of birds, accounts for species of particular interest, new distributional records, and considerations about the conservation of the study area.
4
Macdonald, Ian A. W., Luis Ortiz, Jonas E. Lawesson e J. Bosco Nowak. "The Invasion of Highlands in Galá'pagos by the Red Quinine-tree Cinchona succirubra". Environmental Conservation 15, n. 3 (1988): 215–20. http://dx.doi.org/10.1017/s0376892900029349.
Testo completoAbstract (sommario):
The alien tree species Cinchona succirubra, the Red Quinine-tree (Rubiaceae), was introduced to the Galápagos Islands, Ecuador, in 1946, for purposes of cultivation, but causes much concern as, by 1987, it was found to cover about 4,000 hectares in the highlands of Santa Cruz Island, changing the original, largely endemic, vegetation. Some limited herbicide trials have been made by the Galápagos National Park Service, but a really successful method of controlling this pest still remains to be found.The removal of Cinchona plants from a 1000-ha Intensive Control Area (ICA) within the Galápagos National Park has been successful to date. However, large stands of the tree exist in the adjacent agricultural area of Santa Cruz Island, as well as elsewhere in the National Park. With the maturation of these stands, an increased input of Cinchona succirubra seeds to the ICA can be anticipated.Strengthened use of manual, chemical, and biological, control measures are therefore recommended on a shortterm basis, in order to conserve the unique highland vegetation of Santa Cruz Island, Galápagos.
5
Anderson, R. Scott. "A 35,000 Year Vegetation and Climate History from Potato Lake, Mogollon Rim, Arizona". Quaternary Research 40, n. 3 (novembre 1993): 351–59. http://dx.doi.org/10.1006/qres.1993.1088.
Testo completoAbstract (sommario):
AbstractA new record from Potato Lake, central Arizona, details vegetation and climate changes since the mid-Wisconsin for the southern Colorado Plateau. Recovery of a longer record, discrimination of pine pollen to species groups, and identification of macrofossil remains extend Whiteside's (1965) original study. During the mid-Wisconsin (ca. 35,000-21,000 yr B.P.) a mixed forest of Engelmann spruce (Picea engelmannii) and other conifers grew at the site, suggesting a minimum elevational vegetation depression of ca. 460 m. Summer temperatures were as much as 5°C cooler than today. During the late Wisconsin (ca. 21,000-10,400 yr B.P.), even-cooler temperatures (7°C colder than today; ca. 800 m depression) allowed Engelmann spruce alone to predominate. Warming by ca. 10,400 yr B.P. led to the establishment of the modern ponderosa pine (Pinus ponderosa) forest. Thus, the mid-Wisconsin was not warm enough to support ponderosa pine forests in regions where the species predominates today. Climatic estimates presented here are consistent with other lines of evidence suggesting a cool and/or wet mid-Wisconsin, and a cold and/or wet late-Wisconsin climate for much of the Southwest. Potato Lake was almost completely dry during the mid-Holocene, but lake levels increased to near modern conditions by ca. 3000 yr B.P.
6
Bremond, Laurent, Christopher Carcaillet, Charly Favier, Adam A. Ali, Cédric Paitre, Yves Bégin, Yves Bergeron e Pierre J. H. Richard. "Effects of vegetation zones and climatic changes on fire-induced atmospheric carbon emissions: a model based on paleodata". International Journal of Wildland Fire 19, n. 8 (2010): 1015. http://dx.doi.org/10.1071/wf09096.
Testo completoAbstract (sommario):
An original method is proposed for estimating past carbon emissions from fires in order to understand long-term changes in the biomass burning that, together with vegetation cover, act on the global carbon cycle and climate. The past carbon release resulting from paleo-fires during the Holocene is examined using a simple linear model between measured carbon emissions from modern fires and sedimentary charcoal records of biomass burning within boreal and cold temperate forests in eastern Canada (Quebec, Ontario). Direct carbon emissions are estimated for each ecozone for the present period and the fire anomaly per kilo annum (ka) v. present day (0 ka) deduced from charcoal series of 46 lakes and peats. Over the postglacial, the Taiga Shield ecozone does not match the pattern of fire history and carbon release of Boreal Shield, Atlantic Maritime, and Mixedwood Plains ecozones. This feature results from different air mass influences and the timing of vegetation dynamics. Our estimations show, first, that the contribution of the Mixedwood Plains and the Atlantic Maritime ecozones on the total carbon emissions by fires remains negligible compared with the Boreal Shield. Second, the Taiga Shield plays a key role by maintaining important carbon emissions, given it is today a lower contributor.
7
Polewski, P., J. Shelton, W. Yao e M. Heurich. "SEGMENTATION OF SINGLE STANDING DEAD TREES IN HIGH-RESOLUTION AERIAL IMAGERY WITH GENERATIVE ADVERSARIAL NETWORK-BASED SHAPE PRIORS". ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLIII-B2-2020 (12 agosto 2020): 717–23. http://dx.doi.org/10.5194/isprs-archives-xliii-b2-2020-717-2020.
Testo completoAbstract (sommario):
Abstract. The use of multispectral imagery for monitoring biodiversity in ecosystems is becoming widespread. A key parameter of forest ecosystems is the distribution of dead wood. This work addresses the segmentation of individual dead tree crowns in nadir-view aerial infrared imagery. While dead vegetation produces a distinct spectral response in the near infrared band, separating adjacent trees within large swaths of dead stands remains a challenge. We tackle this problem by casting the segmentation task within the active contour framework, a mathematical formulation combining learned models of the object’s shape and appearance as prior information. We explore the use of a deep convolutional generative adversarial network (DCGAN) in the role of the shape model, replacing the original linear mixture-of-eigenshapes formulation. Also, we rely on probabilities obtained from a deep fully convolutional network (FCN) as the appearance prior. Experiments conducted on manually labeled reference polygons show that the DCGAN is able to learn a low-dimensional manifold of tree crown shapes, outperforming the eigenshape model with respect to the similarity of the reproduced and referenced shapes on about 45 % of the test samples. The DCGAN is successful mostly for less convex shapes, whereas the baseline remains superior for more regular tree crown polygons.
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Lee, J. H., J. Timmermans, Z. Su e M. Mancini. "A new method to calibrate aerodynamic roughness over the Tibetan Plateau using Ensemble Kalman Filter". Hydrology and Earth System Sciences Discussions 9, n. 4 (19 aprile 2012): 5195–224. http://dx.doi.org/10.5194/hessd-9-5195-2012.
Testo completoAbstract (sommario):
Abstract. Aerodynamic roughness height (Zom) is a key parameter required in land surface hydrological model, since errors in heat flux estimations are largely dependent on accurate optimization of this parameter. Despite its significance, it remains an uncertain parameter that is not easily determined. This is mostly because of non-linear relationship in Monin-Obukhov Similarity (MOS) and unknown vertical characteristic of vegetation. Previous studies determined aerodynamic roughness using traditional wind profile method, remotely sensed vegetation index, minimization of cost function over MOS relationship or linear regression. However, these are complicated procedures that presume high accuracy for several other related parameters embedded in MOS equations. In order to simplify a procedure and reduce the number of parameters in need, this study suggests a new approach to extract aerodynamic roughness parameter via Ensemble Kalman Filter (EnKF) that affords non-linearity and that requires only single or two heat flux measurement. So far, to our knowledge, no previous study has applied EnKF to aerodynamic roughness estimation, while a majority of data assimilation study has paid attention to land surface state variables such as soil moisture or land surface temperature. This approach was applied to grassland in semi-arid Tibetan area and maize on moderately wet condition in Italy. It was demonstrated that aerodynamic roughness parameter can inversely be tracked from data assimilated heat flux analysis. The aerodynamic roughness height estimated in this approach was consistent with eddy covariance result and literature value. Consequently, this newly estimated input adjusted the sensible heat overestimated and latent heat flux underestimated by the original Surface Energy Balance System (SEBS) model, suggesting better heat flux estimation especially during the summer Monsoon period. The advantage of this approach over other methodologies is that aerodynamic roughness height estimated in this way is useful even when eddy covariance data are absent and is time-variant over vegetation growth, as well as is not affected by saturation problem of remotely sensed vegetation index.
9
Alencar, Ane, Julia Z. Shimbo, Felipe Lenti, Camila Balzani Marques, Bárbara Zimbres, Marcos Rosa, Vera Arruda et al. "Mapping Three Decades of Changes in the Brazilian Savanna Native Vegetation Using Landsat Data Processed in the Google Earth Engine Platform". Remote Sensing 12, n. 6 (13 marzo 2020): 924. http://dx.doi.org/10.3390/rs12060924.
Testo completoAbstract (sommario):
Widespread in the subtropics and tropics of the Southern Hemisphere, savannas are highly heterogeneous and seasonal natural vegetation types, which makes change detection (natural vs. anthropogenic) a challenging task. The Brazilian Cerrado represents the largest savanna in South America, and the most threatened biome in Brazil owing to agricultural expansion. To assess the native Cerrado vegetation (NV) areas most susceptible to natural and anthropogenic change over time, we classified 33 years (1985–2017) of Landsat imagery available in the Google Earth Engine (GEE) platform. The classification strategy used combined empirical and statistical decision trees to generate reference maps for machine learning classification and a novel annual dataset of the predominant Cerrado NV types (forest, savanna, and grassland). We obtained annual NV maps with an average overall accuracy ranging from 87% (at level 1 NV classification) to 71% over the time series, distinguishing the three main NV types. This time series was then used to generate probability maps for each NV class. The native vegetation in the Cerrado biome declined at an average rate of 0.5% per year (748,687 ha yr−1), mostly affecting forests and savannas. From 1985 to 2017, 24.7 million hectares of NV were lost, and now only 55% of the NV original distribution remains. Of the remnant NV in 2017 (112.6 million hectares), 65% has been stable over the years, while 12% changed among NV types, and 23% was converted to other land uses but is now in some level of secondary NV. Our results were fundamental in indicating areas with higher rates of change in a long time series in the Brazilian Cerrado and to highlight the challenges of mapping distinct NV types in a highly seasonal and heterogeneous savanna biome.
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Fensham, Roderick J., Owen Powell e James Horne. "Rail survey plans to remote sensing: vegetation change in the Mulga Lands of eastern Australia and its implications for land use". Rangeland Journal 33, n. 3 (2011): 229. http://dx.doi.org/10.1071/rj11007.
Testo completoAbstract (sommario):
There is a prevailing paradigm that woody vegetation is expanding at the expense of grassland with reduced burning under pastoralism in the Mulga Lands biogeographic region in eastern Australia. This raises the possibility that the region is acting as a carbon sink. Vegetation boundaries were precisely positioned from rail survey plans dating from 1895 to 1900. This baseline was compared with the position of boundaries on 1952 aerial photography and 2010 Google Earth imagery. The conversion of forest to non-forest by mechanical clearing was also mapped from satellite imagery. There was no consistent trend in the direction of boundary movement for mulga (Acacia aneura F.Muell. ex Benth.), gidgee (Acacia cambagei R.T. Baker) forest or miscellaneous other forest types. The stability of the boundaries, despite the transition from aboriginal management to rangeland pastoralism, contrasts with dramatic declines in tree cover resulting from mechanical clearing. Mapping of forest cover from satellite imagery reveals that conversion of forest to non-forest has reduced mulga forest to 74%, gidgee forest to 30% and miscellaneous forest types to 82% of their original area. Annual clearing rates for the period between 1997 and 2005 were 0.83, 0.95 and 0.43% for those forest types, respectively. Clearing has declined substantially in the period 2005–09 since the advent of recent regulations in Queensland. The area remains a source of carbon emissions but this situation may reverse if restoration of mulga dry forest becomes an attractive land use with an emerging carbon market.
11
Koehl, M., Y. Courtois e S. Guillemin. "3D RECORDING AND MODELLING OF MIDDLE-AGE FORTRESS IN DENSE VEGETATION ENVIRONMENT". ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-2/W5 (18 agosto 2017): 415–20. http://dx.doi.org/10.5194/isprs-archives-xlii-2-w5-415-2017.
Testo completoAbstract (sommario):
The Schwartzenbourg castle is a Middle-Ages fortress which was built in 1261. It is situated above the valley of Munster in Alsace, France. It was mainly used as a fortified place and a jail. In the early 15th century, the structure has deteriorated. Even after some repairs, it fell into ruins during the Thirty Years’ war (1618-1648) and stayed uninhabited. During World War I, the German army used the place as a vantage point and also built a blockhouse inside the ruins. Nowadays, the ruins are gradually collapsing and the remains of the old walls are completely covered by thick plants.<br><br> The goal of this project was to create a 3D-model of the site before closing its access, which became too dangerous for people. This modelling is divided into two elements: on one hand, a digital terrain model (DTM) of the site in order to replace the castle and to analyze the background of its original environment; on the other hand, a 3D modelling of the ruins of the castle invaded by the vegetation. Indeed, the main difficulty of the measurement is obviously the dense vegetation which hides the castle. Held back for years outside the castle, it has now become an integral part of the ruins. This vegetation is finally today usually the first threat of heritage buildings. After a preliminary inspection of the site as well as difficulties of the project, the first step consisted of the survey of the whole environment of the site. We will therefore describe the different phases of the survey with the initial implementation of a georeferenced network on site. We will present the terrestrial laser scanning (TLS) surveys, then complementary surveys carried out by aerial photogrammetry. To be implemented, we had to wait for an advanced autumn in order to have as few leaves on trees as possible. The major step of processing of point clouds described in this paper is then the extraction of a DTM by using techniques to pass through the vegetation, or better to segment the points into different classes, one of these that would be the soil i.e. DTM, another consists into wall parts of the ruins.
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Vorobyev, Sergey, Andrey Bychkov, Vanda Khilimonyuk, Sergey Buldovicz, Evgeny Ospennikov e Evgeny Chuvilin. "Formation of the Yamal Crater in Northern West Siberia: Evidence from Geochemistry". Geosciences 9, n. 12 (14 dicembre 2019): 515. http://dx.doi.org/10.3390/geosciences9120515.
Testo completoAbstract (sommario):
In the framework of this work, studies on the Yamal crater formed as a result of a cryogenic eruption of a water-gas fluid were carried out. The structure and variations of the composition of the geochemical field along the section of the upper horizons of permafrost are considered on the basis of field work, including the drilling of boreholes near the crater. The obtained regularities of the distribution of chemical elements, and gases between the mineral component of the soil and meltwater, suggest that permafrost at the site of the funnel are the remains of a sub-lake paleo-talik, from which mineralized water and gases were expulsed into the yet unfrozen reservoir that previously existed at this place. The component composition of gases suggests that they are products of biochemical processes similar to those that occur in modern peatlands. The δ13C value for methane extracted from the sediments of the near-contact zone of the Yamal crater was found to be −76‰. The predominance of high molecular weight normal alkanes in frozen bitumen indicates that the original organic substrate which was buried contained remains of higher vegetation. The Yamal funnel was formed by the sediment’s “explosion” while the water-gas fluid was released. The volume of the ejected sediment amounted to about 220 thousand m3.
13
Lee, J. H., J. Timmermans, Z. Su e M. Mancini. "Calibration of aerodynamic roughness over the Tibetan Plateau with Ensemble Kalman Filter analysed heat flux". Hydrology and Earth System Sciences 16, n. 11 (20 novembre 2012): 4291–302. http://dx.doi.org/10.5194/hess-16-4291-2012.
Testo completoAbstract (sommario):
Abstract. Aerodynamic roughness height (Zom) is a key parameter required in several land surface hydrological models, since errors in heat flux estimation are largely dependent on optimization of this input. Despite its significance, it remains an uncertain parameter which is not readily determined. This is mostly because of non-linear relationship in Monin-Obukhov similarity (MOS) equations and uncertainty of vertical characteristic of vegetation in a large scale. Previous studies often determined aerodynamic roughness using a minimization of cost function over MOS relationship or linear regression over it, traditional wind profile method, or remotely sensed vegetation index. However, these are complicated procedures that require a high accuracy for several other related parameters embedded in serveral equations including MOS. In order to simplify this procedure and reduce the number of parameters in need, this study suggests a new approach to extract aerodynamic roughness parameter from single or two heat flux measurements analyzed via Ensemble Kalman Filter (EnKF) that affords non-linearity. So far, to our knowledge, no previous study has applied EnKF to aerodynamic roughness estimation, while the majority of data assimilation study have paid attention to updates of other land surface state variables such as soil moisture or land surface temperature. The approach of this study was applied to grassland in semi-arid Tibetan Plateau and maize on moderately wet condition in Italy. It was demonstrated that aerodynamic roughness parameter can be inversely tracked from heat flux EnKF final analysis. The aerodynamic roughness height estimated in this approach was consistent with eddy covariance method and literature value. Through a calibration of this parameter, this adjusted the sensible heat previously overestimated and latent heat flux previously underestimated by the original Surface Energy Balance System (SEBS) model. It was considered that this improved heat flux estimation especially during the summer Monsoon period, based upon a comparison with precipitation and soil moisture field measurement. For an advantage of this approach over other previous methodologies, this approach is useful even when eddy covariance data are absent at a large scale and is time-variant over vegetation growth, as well as is not directly affected by saturation problem of remotely sensed vegetation index.
14
Harjadi, Beny. "Climate Change Vulnerability Analysis of Baluran National Park". Forum Geografi 30, n. 2 (13 dicembre 2016): 140. http://dx.doi.org/10.23917/forgeo.v30i2.1000.
Testo completoAbstract (sommario):
Every ecosystem has a different level of susceptibility to environmental disturbances it receives, both from natural factors or anthropogenic disturbance. National Park (NP) Baluran is one national park that has a representation of a complete ecosystem that includes upland forest ecosystems, lowland forests, coastal forests, mangroves, savanna and evergreen forest. The objective of this study is to get a formula calculation of vulnerability analysis of constant and dynamic factors. Baluran NP vulnerability assessment to climate change done by looking at the dynamic and fixed factors. Vulnerability remains a vulnerability factor to the condition of the original (control), whereas vulnerability is the vulnerability of the dynamic change factors which affected the condition from the outside. Constant Vulnerability (CV) in Baluran NP dominated resistant conditions (61%), meaning that the geomorphology and other fixed factors (slope and slope direction/aspect, then the condition in Baluran NP sufficiently resilient to climate change. Dynamic Vulnerability (DV) is the vulnerability of an area or areas that change because of pressure from external factors. DV is influenced by climatic factors (WI = Wetness Index), soil (SBI = Soil Brightness Index), and vegetation (GI = Greenness Index). DV in Baluran NP from 1999 to 2010 shifted from the original category of being (84.76%) and shifted to the susceptible (59.88%). The role of remote sensing for the analysis of raster digital system, while the geographic information system to display the results of cartographic maps.
15
Wilson, Brian R., Ivor Growns e John Lemon. "Scattered native trees and soil patterns in grazing land on the Northern Tablelands of New South Wales, Australia". Soil Research 45, n. 3 (2007): 199. http://dx.doi.org/10.1071/sr07019.
Testo completoAbstract (sommario):
Over large areas of south-eastern Australia, the original cover of native woodland has been extensively cleared or modified, and what remains is often characterised by scattered trees beneath which the ground-storey vegetation is largely grazed or otherwise managed. This study investigated the influence of scattered Blakely’s red gum (Eucalyptus blakelyi) trees on both near-surface and deeper soil layers in temperate grazed pastures on the Northern Tablelands of New South Wales, Australia. A significant canopy effect was observed with elevated soil pH, carbon, and nutrient status inside the tree canopy indicating soil enrichment in a zone around the tree. This effect, however, was largely restricted to the surface (0–0.20 m) soil layers. Chloride concentrations were elevated near to trees but only in the deeper soil layers, suggesting that a modified water use and deep drainage mechanism occurred near the trees. Close to the tree, however, a significant acidification was observed between 0.40–0.60 m depth in the soil, without any obvious depletion in other soil element concentrations. It is concluded that this acidification provides strong evidence in support of a ‘biological pumping’ mechanism that has been proposed elsewhere. Key questions remain as to the management implications of these results, whether the subsurface acidification that was observed is common among native Australian trees, if it might be persistent through time, and if this might be a soil issue that requires management.
16
Hamelin, Louis-Edmond. "Le « Sertão » du « Nordeste » (Brésil). Essai de définition d’un « pays »." Cahiers de géographie du Québec 2, n. 4 (12 aprile 2005): 241–48. http://dx.doi.org/10.7202/020091ar.
Testo completoAbstract (sommario):
Despite the fact that Brazil is a young and vast country, some of its regions have already acquired a personality of their own. The Sertâo in the Northeast is such a case. Of triangular shape, the Sertâo opens in the North, towards the Atlantic ocean ; it covers 10% of the total area of Brazil and include more than 90% of the states of Rio Grande do Norte, Ceara and Paraiba. It is a semi arid region with a dry climate, chiefly responsible for an original type of vegetation : the caatinga. The fundamental features of the relief are horizontal with depressions and inselbergs. The rare good soils are deteriorated and the hydrographic network is fair. Such a severe country is inhabitated by 7 millions persons of mixed ethnic origins. The dominant occupational types, are the vaqueiro, the garimpeiro, the truck driver , and, during the dry season, the flagellado. It is an « under-developped » country economically , with low standards of living, and a production based on food and cattle. If the Sertao is unsafe foreigners, it remains for the natives, a mystical and attractive country that may become more prosperous with the hydro-electric development of the Sao Francisco River.
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JENKINS, JULIA, ROBERT E. SIMMONS, ODETTE CURTIS, MARION ATYEO, DOMATILLA RAIMONDO e ANDREW R. JENKINS. "The value of the Black HarrierCircus maurusas a predictor of biodiversity in the plant-rich Cape Floral Kingdom, South Africa". Bird Conservation International 23, n. 1 (14 marzo 2012): 66–77. http://dx.doi.org/10.1017/s0959270911000323.
Testo completoAbstract (sommario):
SummaryDetermining the efficacy of using indicator species to predict the spatial location of biodiversity hotspots is one way of maximising the conservation of biodiversity in already threatened habitats. Recent evidence from Europe suggests raptors can play such an indicator role, so we tested this approach with a globally threatened southern hemisphere species, the Black HarrierCircus maurus. We asked if this species, found in South Africa’s mega-diverse Cape Floral Kingdom, breeds in habitat fragments that were more diverse in terms of small mammals, birds and plants than unoccupied fragments of similar size. Renosterveld is a highly fragmented habitat that has lost > 90% of its original extent and remains only on privately-owned lands. Surveys of small mammals, birds and plants undertaken in 20 fragments in the Overberg region, South Africa, revealed nine with breeding harriers and 11 without harriers. Harrier-occupied fragments were associated with a 3.5 fold higher number of bird species and higher small mammal species richness than unoccupied ones. There was a lower abundance of most plants in occupied patches, except for red grassThemeda triandrawhich is an indicator of pristine renosterveld. Vegetation structure was significantly different, with harriers nesting on patches with taller, more open vegetation. While the diversity trends were not statistically significant, a positive trend between the presence of harriers and higher abundance of red grass – as an indicator of the more pristine state of the patch, suggests that harriers might allow biodiversity managers a heuristic approach for selecting the remaining patches of pristine renosterveld. The need for intensive sampling of several taxa leads to small samples and a lack of clear-cut trends for these top predators as indicators of plant diversity.
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Buerki, Sven, Martin W. Callmander, Steven Bachman, Justin Moat, Jean-Noël Labat e Félix Forest. "Incorporating evolutionary history into conservation planning in biodiversity hotspots". Philosophical Transactions of the Royal Society B: Biological Sciences 370, n. 1662 (19 febbraio 2015): 20140014. http://dx.doi.org/10.1098/rstb.2014.0014.
Testo completoAbstract (sommario):
There is increased evidence that incorporating evolutionary history directly in conservation actions is beneficial, particularly given the likelihood that extinction is not random and that phylogenetic diversity (PD) is lost at higher rates than species diversity. This evidence is even more compelling in biodiversity hotspots, such as Madagascar, where less than 10% of the original vegetation remains. Here, we use the Leguminosae, an ecologically and economically important plant family, and a combination of phylogenetics and species distribution modelling, to assess biodiversity patterns and identify regions, coevolutionary processes and ecological factors that are important in shaping this diversity, especially during the Quaternary. We show evidence that species distribution and community PD are predicted by watershed boundaries, which enable the identification of a network of refugia and dispersal corridors that were perhaps important for maintaining community integrity during past climate change. Phylogenetically clustered communities are found in the southwest of the island at low elevation and share a suite of morphological characters (especially fruit morphology) indicative of coevolution with their main dispersers, the extinct and extant lemurs. Phylogenetically over-dispersed communities are found along the eastern coast at sea level and may have resulted from many independent dispersal events from the drier and more seasonal regions of Madagascar.
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van der Ree, Rodney, Todd R. Soderquist e Andrew F. Bennett. "Home-range use by the brush-tailed phascogale (Phascogale tapoatafa) (Marsupialia) in high-quality, spatially limited habitat". Wildlife Research 28, n. 5 (2001): 517. http://dx.doi.org/10.1071/wr00051.
Testo completoAbstract (sommario):
Nine phascogales (7 females, 2 males) were radio-tracked between March and July 1999 to investigate the spatial organisation of this species in spatially limited habitat near Euroa, Victoria. In this area, approximately 3.6% of the original woodland vegetation remains after 150 years of agricultural clearing. Most wooded habitat is confined to narrow linear strips along roads and streams. However, these remnants are on fertile soils and, because they have not experienced intensive harvesting, the density of large old trees is over 10 times that found in nearby State Forests and Parks. Female phascogales were monitored for 13–38 days over periods of 5–15 weeks. The size of home ranges of females was 2.3–8.0 ha, and averaged 5.0 ha. This value is one-eighth the mean home-range size previously recorded for the species in contiguous forest in Victoria. All individuals used multiple nest trees, with nests generally located in trees >80 cm diameter at breast height. Although fragmented and spatially limited, the stands of large old trees on productive soils near Euroa provide a network of well connected, high-quality habitat for phascogales. The relatively dense population of phascogales in these remnants suggests that prior to agricultural clearing and timber harvesting, phascogales may have been much more common in Victoria than at present.
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Flores Martínez, Juan Jose, Jorge Ortega e Guillermo Ibarra Manríquez. "Hábitos alimentarios del murciélago zapotero (Artibeus jamaicensis) en Yucatán." Revista Mexicana de Mastozoología (Nueva Epoca) 4, n. 1 (1 gennaio 1999): 22. http://dx.doi.org/10.22201/ie.20074484e.1999.4.1.79.
Testo completoAbstract (sommario):
Resumen: Se describió el hábito alimentario del murciélago zapotero (Artibeus jamaicensis) en dos cuevas del estado de Yucatán, México, rodeadas con pequeños parches de vegetación nativa (selva baja caducifolia) y vegetación antropogénica (cultivos y huertos familiares) A pesar de los frutos de 28 especies fueron consumidos por los murciélagos, solamente cinco de ellas resultaron dominantes durante todo el año (Cecropia peltata, Solanum hirtum, Ficus spp. (dos especies) y Vitex gaumeri). Diez de las plantas consumidas por A. jamaicensis en este trabajo se reportan por primera vez en su dieta. Cerca de 12 especies fueron registradas en promedio por mes, con el valor más alto hacia finales de la época de lluvias (septiembre) y los valores más bajos cuando se inicia la temporada de menor precipitación (diciembre y enero). Las especies nativas tuvieron siempre una mayor aportación en el número y peso de semillas en la dieta de A. jamaicensis que las cultivadas (75-100% de cada mes), pero el consumo de ambos recursos muestra el oportunismo de la especie para adecuarse a hábitats perturbados.Abstract:Food preferences for the Jamaican fruit-eating bat (Artibeus jamaicensis) was documented during a year round in two caves of Yucatan, Mexico. Vegetation around the sites was classified as anthropogenic vegetation (crops and backyard house) and scarce remains of original forest (tropical deciduous forest). In spite of 28 species eaten by the Jamaican fruit-eating bat, only five comprise the bulk of the diet (Cecropia peltata, Solanum hirtum, Ficus spp. (two species), and Vitex gaumeri). Ten plant species were reported as the first time in the diet of A. jamaicensis. Around of 12 species were recording each month, with the high values at end of rain season (September) and the lower in the beginning at dry season (December and January). Fruits produced by native plants were preferred over cropped plants (75-100% of each month), but the both kinds of fruits presented in the feces demonstrate the opportunism of the species in disturbed areas.Palabras clave: Artibeus jamaicensis, hábito alimentario, Yucatán, selva baja caducifolia, vegetación secundaria, dominantes, cultivadas, no cultivadas.
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Sapanov, M. K. "Peculiarities and ecological consequences of climate warming in the Northern Caspian semi-desert". Povolzhskiy Journal of Ecology, n. 1 (18 maggio 2021): 64–78. http://dx.doi.org/10.35885/1684-7318-2021-1-64-78.
Testo completoAbstract (sommario):
Data on the weather conditions and monitoring of vegetation ecosystems in the Northern Caspian semi-desert for the 70-year period were analyzed. A gradual increase in the average air temperature per hydrological year by 2.73ºC (0.039ºC/year) has been revealed. Before and after the 2000s its increase was caused by warming of the cold and warm period of the year, respectively. An increase of the annual atmospheric precipitation in the spring-summer period was detected, mainly in 1978–1995 due to April-June precipitation. The humidification coefficient dynamics allows distinguishing three periods. The first period (1951–1977) is characterized by insignificant fluctuations around the average value (0.30); the second period (1978–1994) is characterized by good moisture, and the third period (1995–2020), on the contrary, – by severe aridity. These climate changes have led to significant transformation of the snow cover formation mechanisms, the surface runoff of spring melt water, and the ground water level. Despite such fluctuations of natural conditions, the annual productivity of virgin vegetation remains in dynamic equilibrium, changing over time in a wave-like manner, with no introduction of heterogeneous species. The protective afforestation has no chance for sustainable development due to warming of the winter months by 2000, which led to the absence of additional moistening of forest crops for a long period due to the deficiency of snow accumulation and surface inflow of spring melt water. The shrinkage of forest stands was intensified by recurrent annual summer atmospheric droughts. The production of agricultural crops was discontinued since the mid-1990s due to their annual failure, as well as the aridity of the growing seasons. The climate warming of the last two decades has brought the landscape of the flat semi-desert territory of the Northern Caspian region ever closer to its original state without agricultural fields and forest plantations. The population of the region is forced to return to extensive cattle breeding, which has existed here since ancient times.
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CARDOSO, PEDRO HENRIQUE, VANESSA IMACULADA DOS REIS VALÉRIO, LUIZ MENINI NETO e FÁTIMA REGINA GONÇALVES SALIMENA. "Verbenaceae in Espírito Santo, Brazil: richness, patterns of geographic distribution and conservation". Phytotaxa 484, n. 1 (15 febbraio 2021): 1–43. http://dx.doi.org/10.11646/phytotaxa.484.1.1.
Testo completoAbstract (sommario):
Verbenaceae is represented in Brazil by 15 genera and ca. 290 species, with most of its richness in the Cerrado and Atlantic Forest domains. The state of Espírito Santo has an area of 46,184.1 km2, wholly embedded in the Atlantic Forest. Nonetheless, due to the intense environmental degradation in the state, only 10.5% of its original vegetation remains. The present study is part of the “Flora do estado do Espírito Santo” project and aims to provide a taxonomic treatment to Verbenaceae in the state, as well as to analyze its distribution patterns, together with preliminary conservation assessments for each species. It is based on morphological analysis of herbaria collections, field expeditions, and literature compilation. Distribution maps were made for each species, while the preliminary conservation assessments followed the criteria proposed by the IUCN. Verbenaceae is represented in the state of Espírito Santo by 31 species arranged in 11 genera: Aloysia (2 spp.), Bouchea (1 sp.). Casselia (1 sp.), Citharexylum (1 sp.), Glandularia (1 sp.), Lantana (10 spp.), Lippia (4 spp.), Petrea (1 sp.), Priva (2 spp.), Stachytarpheta (6 spp.) and Verbena (2 spp.). Eight species occurring in Espírito Santo are threatened with extinction. Three new records are verified, including species of the genus Lantana. The dense rainforest, which covers most of the state’s territory, presents the most significant number of species (20 spp.), followed by pioneer vegetations (12 spp.), seasonal semideciduous forests (11 spp.), inselbergs (8 spp.), and ecological refuges (2 spp.). The main richness centers for Verbenaceae in the state of Espírito Santo are the municipalities of Linhares, Santa Teresa, Vitória, Vila Velha, and Guarapari in this order. In contrast, the family is noticeably little represented in the northern region of the state, as well as near its borders, where the forest remnants are highly fragmented and scattered. The current results contribute to the taxonomic and biogeographic knowledge of Verbenaceae, to the creation of conservation strategies for threatened species in the State of sspírito Santo, and reinforce the need of fieldwork in several areas of the state.
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Roche, Kévin, Isabelle Jouffroy-Bapicot, Boris Vannière e Matthieu Le Bailly. "Ancient parasites from a peat bog: New insights into animal presence and husbandry in Crete over the past 2000 years". Holocene 30, n. 9 (7 maggio 2020): 1243–53. http://dx.doi.org/10.1177/0959683620919984.
Testo completoAbstract (sommario):
This paper presents an original palaeoparasitological study performed on samples from a sedimentary core in a peat bog (Asi Gonia, White Mountains, Crete, Greece). The aim of the study is to test the preservation and concentration of parasitic remains in peat sediments, to discuss animal presence around the site throughout the record, and to compare the results with other biomarkers of environmental history. In this aim, 22 sediment samples distributed between the Roman period and the present were processed and the residues were observed under light microscopy in search of parasitic markers (microscopic eggs or oocysts). The majority of the samples (86.4%) tested positive for the presence of helminth eggs. Several taxa were observed throughout the studied period, including Trichuris sp., Ascaris sp., Capillaria sp., Fasciola sp., Paramphistomum sp. and Macracanthorhynchus sp. The assemblage of parasite markers changes throughout the record and the variations show close correlations with previously published grazing indicators (fungal spores) and vegetation changes (pollen grains). This study sheds lights on animal associations and changing environments in the watershed over the past 2000 years. Indeed, we detected three main phases consisting of: Roman animal herding with pigs in an evergreen oak forest, then a more irregular but almost constant presence of ruminants during a second Byzantine and modern phase in a heather maquis landscape and, finally, present-day grazing in a phrygana/steppe landscape. These results highlight how palaeoparasitology can contribute to multi-proxy approaches in peat bog sedimentary sequences.
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Yoder, Anne D., C. Ryan Campbell, Marina B. Blanco, Mario dos Reis, Jörg U. Ganzhorn, Steven M. Goodman, Kelsie E. Hunnicutt et al. "Geogenetic patterns in mouse lemurs (genus Microcebus) reveal the ghosts of Madagascar's forests past". Proceedings of the National Academy of Sciences 113, n. 29 (18 luglio 2016): 8049–56. http://dx.doi.org/10.1073/pnas.1601081113.
Testo completoAbstract (sommario):
Phylogeographic analysis can be described as the study of the geological and climatological processes that have produced contemporary geographic distributions of populations and species. Here, we attempt to understand how the dynamic process of landscape change on Madagascar has shaped the distribution of a targeted clade of mouse lemurs (genus Microcebus) and, conversely, how phylogenetic and population genetic patterns in these small primates can reciprocally advance our understanding of Madagascar's prehuman environment. The degree to which human activity has impacted the natural plant communities of Madagascar is of critical and enduring interest. Today, the eastern rainforests are separated from the dry deciduous forests of the west by a large expanse of presumed anthropogenic grassland savanna, dominated by the Family Poaceae, that blankets most of the Central Highlands. Although there is firm consensus that anthropogenic activities have transformed the original vegetation through agricultural and pastoral practices, the degree to which closed-canopy forest extended from the east to the west remains debated. Phylogenetic and population genetic patterns in a five-species clade of mouse lemurs suggest that longitudinal dispersal across the island was readily achieved throughout the Pleistocene, apparently ending at ∼55 ka. By examining patterns of both inter- and intraspecific genetic diversity in mouse lemur species found in the eastern, western, and Central Highland zones, we conclude that the natural environment of the Central Highlands would have been mosaic, consisting of a matrix of wooded savanna that formed a transitional zone between the extremes of humid eastern and dry western forest types.
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Zheng, Yi, Ruoque Shen, Yawen Wang, Xiangqian Li, Shuguang Liu, Shunlin Liang, Jing M. Chen, Weimin Ju, Li Zhang e Wenping Yuan. "Improved estimate of global gross primary production for reproducing its long-term variation, 1982–2017". Earth System Science Data 12, n. 4 (12 novembre 2020): 2725–46. http://dx.doi.org/10.5194/essd-12-2725-2020.
Testo completoAbstract (sommario):
Abstract. Satellite-based models have been widely used to simulate vegetation gross primary production (GPP) at the site, regional, or global scales in recent years. However, accurately reproducing the interannual variations in GPP remains a major challenge, and the long-term changes in GPP remain highly uncertain. In this study, we generated a long-term global GPP dataset at 0.05∘ latitude by 0.05∘ longitude and 8 d interval by revising a light use efficiency model (i.e., EC-LUE model). In the revised EC-LUE model, we integrated the regulations of several major environmental variables: atmospheric CO2 concentration, radiation components, and atmospheric vapor pressure deficit (VPD). These environmental variables showed substantial long-term changes, which could greatly impact the global vegetation productivity. Eddy covariance (EC) measurements at 95 towers from the FLUXNET2015 dataset, covering nine major ecosystem types around the globe, were used to calibrate and validate the model. In general, the revised EC-LUE model could effectively reproduce the spatial, seasonal, and annual variations in the tower-estimated GPP at most sites. The revised EC-LUE model could explain 71 % of the spatial variations in annual GPP over 95 sites. At more than 95 % of the sites, the correlation coefficients (R2) of seasonal changes between tower-estimated and model-simulated GPP are larger than 0.5. Particularly, the revised EC-LUE model improved the model performance in reproducing the interannual variations in GPP, and the averaged R2 between annual mean tower-estimated and model-simulated GPP is 0.44 over all 55 sites with observations longer than 5 years, which is significantly higher than those of the original EC-LUE model (R2=0.36) and other LUE models (R2 ranged from 0.06 to 0.30 with an average value of 0.16). At the global scale, GPP derived from light use efficiency models, machine learning models, and process-based biophysical models shows substantial differences in magnitude and interannual variations. The revised EC-LUE model quantified the mean global GPP from 1982 to 2017 as 106.2±2.9 Pg C yr−1 with the trend 0.15 Pg C yr−1. Sensitivity analysis indicated that GPP simulated by the revised EC-LUE model was sensitive to atmospheric CO2 concentration, VPD, and radiation. Over the period of 1982–2017, the CO2 fertilization effect on the global GPP (0.22±0.07 Pg C yr−1) could be partly offset by increased VPD (-0.17±0.06 Pg C yr−1). The long-term changes in the environmental variables could be well reflected in global GPP. Overall, the revised EC-LUE model is able to provide a reliable long-term estimate of global GPP. The GPP dataset is available at https://doi.org/10.6084/m9.figshare.8942336.v3 (Zheng et al., 2019).
26
Zhang, Yuan, Ana Bastos, Fabienne Maignan, Daniel Goll, Olivier Boucher, Laurent Li, Alessandro Cescatti et al. "Modeling the impacts of diffuse light fraction on photosynthesis in ORCHIDEE (v5453) land surface model". Geoscientific Model Development 13, n. 11 (10 novembre 2020): 5401–23. http://dx.doi.org/10.5194/gmd-13-5401-2020.
Testo completoAbstract (sommario):
Abstract. Aerosol- and cloud-induced changes in diffuse light have important impacts on the global land carbon cycle, as they alter light distribution and photosynthesis in vegetation canopies. However, this effect remains poorly represented or evaluated in current land surface models. Here, we add a light partitioning module and a new canopy light transmission module to the ORCHIDEE (Organising Carbon and Hydrology In Dynamic Ecosystems) land surface model (trunk version, v5453) and use the revised model, ORCHIDEE_DF, to estimate the fraction of diffuse light and its effect on gross primary production (GPP) in a multilayer canopy. We evaluate the new parameterizations using flux observations from 159 eddy covariance sites over the globe. Our results show that, compared with the original model, ORCHIDEE_DF improves the GPP simulation under sunny conditions and captures the observed higher photosynthesis under cloudier conditions in most plant functional types (PFTs). Our results also indicate that the larger GPP under cloudy conditions compared with sunny conditions is mainly driven by increased diffuse light in the morning and in the afternoon as well as by a decreased vapor pressure deficit (VPD) and decreased air temperature at midday. The observations show that the strongest positive effects of diffuse light on photosynthesis are found in the range from 5 to 20 ∘C and at a VPD < 1 kPa. This effect is found to decrease when the VPD becomes too large or the temperature falls outside of the abovementioned range, which is likely due to the increasing stomatal resistance to leaf CO2 uptake. ORCHIDEE_DF underestimates the diffuse light effect at low temperature in all PFTs and overestimates this effect at high temperature and at a high VPD in grasslands and croplands. The new model has the potential to better investigate the impact of large-scale aerosol changes and long-term changes in cloudiness on the terrestrial carbon budget, both in the historical period and in the context of future air quality policies and/or climate engineering.
27
Araujo, Cybele de Oliveira, Décio Tadeu Corrêa Filho e Ricardo Jannini Sawaya. "Snake assemblage of Estação Ecológica de Santa Bárbara, SP: a Cerrado remnant in Southeastern Brazil". Biota Neotropica 10, n. 2 (giugno 2010): 235–45. http://dx.doi.org/10.1590/s1676-06032010000200026.
Testo completoAbstract (sommario):
Despite the great extension of the Cerrado and its importance for biodiversity conservation, there are still sampling gaps in this region that has shown conspicuous changes over the years due to the conversion of natural areas into pastures and plantations. Around 88.5% of the Cerrado areas in the State of the São Paulo were cleared in the last four decades and less than 0.81% of the original Cerrado vegetation remains as pristine habitats, although these areas once covered 14% of the state. We present the list of snakes that occur in the Estação Ecológica de Santa Bárbara, a remnant of Cerrado in the State of São Paulo, in addition to information on the abundance and distribution of species in the various habitats found at this location. The survey was conducted between October 2008 and March 2009 during six monthly field trips of five days each, totaling 30 sampling days. Surveys were conducted using incidental encounters (IE) and pitfall traps (PT). We recorded a total of 21 species belonging to 15 genera and six families. All species and individuals captured (18 species; 49 individuals) were found in open Cerrado formations. No individual was observed in the sampled forest habitats (cerradão and dry forest). Forested habitats occupy a relatively small portion of this protected area (12.6%). However, the higher species richness in open habitats may not be a result of limited local coverage of forests. The higher richness in interfluvial open habitats has also been recorded in other Cerrado areas. This survey is an important contribution towards enhancing our knowledge about the snake assemblage in the highly threatened Cerrado of São Paulo State. Hence, these last protected remnants in the state that still house significant areas of open Cerrado formations, such as the Estação Ecológica de Santa Bárbara, although reduced, are extremely important for the conservation of reptiles in the State of São Paulo, in Southeastern Brazil, and in the Cerrado region.
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Morissette, Ève-Marie, Claude Lavoie e Jean Huot. "Fairy slipper (Calypso bulbosa) on Anticosti Island: the occurrence of a rare plant in an environment strongly modified by white-tailed deer". Botany 87, n. 12 (dicembre 2009): 1223–31. http://dx.doi.org/10.1139/b09-082.
Testo completoAbstract (sommario):
The introduction of white-tailed deer ( Odocoileus virginianus Zimm.) at the end of the 19th century, and their subsequent proliferation on Anticosti Island (Quebec) has had a strong impact on forest vegetation. Only 50% of the original balsam fir ( Abies balsamea (L.) Mill.) cover remains on the island, and fir has been progressively replaced by white spruce ( Picea glauca (Moench) Voss) because of browsing. This phenomenon may have an impact on rare species, such as the fairy slipper orchid ( Calypso bulbosa (L.) Oakes; Orchidaceae), associated with old fir stands. In this study, we mapped fairy slipper populations on Anticosti Island and collected data on its habitat. We developed a statistical model to identify key environmental characteristics predicting the presence or the absence of the species. We hypothesized that on Anticosti Island, the fairy slipper is restricted to old-growth fir stands located on calcareous soils; consequently, this orchid is endangered because its habitat is gradually disappearing. A total of 69 sampling stations were surveyed along three transects crossing the island. The fairy slipper was present in 19 of the 69 stations. A fir stand, with a large quantity of dead logs and low levels of tree and moss cover, is more likely to harbour a fairy slipper population than any other forest stand. It is possible that on Anticosti Island, the presence of the fairy slipper is associated with forest age and structure (the latter being strongly influenced by deer) rather than with fir per se. Moreover, deer, by browsing shrubs and fir seedlings and saplings, have apparently had a positive impact on the fairy slipper population by eliminating competition between this orchid and other understory plants. On the other hand, deer have hampered the regeneration of fir forests; old fir stands that were eliminated by blowdowns, insect outbreaks, fires or logging have been replaced by spruce stands. This may have an impact on the long term survival of the fairy slipper, unless spruce stands soon provide suitable habitats for the species as they mature.
29
Nijzink, Remko C., Luis Samaniego, Juliane Mai, Rohini Kumar, Stephan Thober, Matthias Zink, David Schäfer, Hubert H. G. Savenije e Markus Hrachowitz. "The importance of topography-controlled sub-grid process heterogeneity and semi-quantitative prior constraints in distributed hydrological models". Hydrology and Earth System Sciences 20, n. 3 (17 marzo 2016): 1151–76. http://dx.doi.org/10.5194/hess-20-1151-2016.
Testo completoAbstract (sommario):
Abstract. Heterogeneity of landscape features like terrain, soil, and vegetation properties affects the partitioning of water and energy. However, it remains unclear to what extent an explicit representation of this heterogeneity at the sub-grid scale of distributed hydrological models can improve the hydrological consistency and the robustness of such models. In this study, hydrological process complexity arising from sub-grid topography heterogeneity was incorporated into the distributed mesoscale Hydrologic Model (mHM). Seven study catchments across Europe were used to test whether (1) the incorporation of additional sub-grid variability on the basis of landscape-derived response units improves model internal dynamics, (2) the application of semi-quantitative, expert-knowledge-based model constraints reduces model uncertainty, and whether (3) the combined use of sub-grid response units and model constraints improves the spatial transferability of the model. Unconstrained and constrained versions of both the original mHM and mHMtopo, which allows for topography-based sub-grid heterogeneity, were calibrated for each catchment individually following a multi-objective calibration strategy. In addition, four of the study catchments were simultaneously calibrated and their feasible parameter sets were transferred to the remaining three receiver catchments. In a post-calibration evaluation procedure the probabilities of model and transferability improvement, when accounting for sub-grid variability and/or applying expert-knowledge-based model constraints, were assessed on the basis of a set of hydrological signatures. In terms of the Euclidian distance to the optimal model, used as an overall measure of model performance with respect to the individual signatures, the model improvement achieved by introducing sub-grid heterogeneity to mHM in mHMtopo was on average 13 %. The addition of semi-quantitative constraints to mHM and mHMtopo resulted in improvements of 13 and 19 %, respectively, compared to the base case of the unconstrained mHM. Most significant improvements in signature representations were, in particular, achieved for low flow statistics. The application of prior semi-quantitative constraints further improved the partitioning between runoff and evaporative fluxes. In addition, it was shown that suitable semi-quantitative prior constraints in combination with the transfer-function-based regularization approach of mHM can be beneficial for spatial model transferability as the Euclidian distances for the signatures improved on average by 2 %. The effect of semi-quantitative prior constraints combined with topography-guided sub-grid heterogeneity on transferability showed a more variable picture of improvements and deteriorations, but most improvements were observed for low flow statistics.
30
Nijzink, R. C., L. Samaniego, J. Mai, R. Kumar, S. Thober, M. Zink, D. Schäfer, H. H. G. Savenije e M. Hrachowitz. "The importance of topography controlled sub-grid process heterogeneity in distributed hydrological models". Hydrology and Earth System Sciences Discussions 12, n. 12 (21 dicembre 2015): 13301–58. http://dx.doi.org/10.5194/hessd-12-13301-2015.
Testo completoAbstract (sommario):
Abstract. Heterogeneity of landscape features like terrain, soil, and vegetation properties affect the partitioning of water and energy. However, it remains unclear to which extent an explicit representation of this heterogeneity at the sub-grid scale of distributed hydrological models can improve the hydrological consistency and the robustness of such models. In this study, hydrological process complexity arising from sub-grid topography heterogeneity was incorporated in the distributed mesoscale Hydrologic Model (mHM). Seven study catchments across Europe were used to test whether (1) the incorporation of additional sub-grid variability on the basis of landscape-derived response units improves model internal dynamics, (2) the application of semi-quantitative, expert-knowledge based model constraints reduces model uncertainty; and (3) the combined use of sub-grid response units and model constraints improves the spatial transferability of the model. Unconstrained and constrained versions of both, the original mHM and mHMtopo, which allows for topography-based sub-grid heterogeneity, were calibrated for each catchment individually following a multi-objective calibration strategy. In addition, four of the study catchments were simultaneously calibrated and their feasible parameter sets were transferred to the remaining three receiver catchments. In a post-calibration evaluation procedure the probabilities of model and transferability improvement, when accounting for sub-grid variability and/or applying expert-knowledge based model constraints, were assessed on the basis of a set of hydrological signatures. In terms of the Euclidian distance to the optimal model, used as overall measure for model performance with respect to the individual signatures, the model improvement achieved by introducing sub-grid heterogeneity to mHM in mHMtopo was on average 13 %. The addition of semi-quantitative constraints to mHM and mHMtopo resulted in improvements of 13 and 19 % respectively, compared to the base case of the unconstrained mHM. Most significant improvements in signature representations were, in particular, achieved for low flow statistics. The application of prior semi-quantitative constraints further improved the partitioning between runoff and evaporative fluxes. Besides, it was shown that suitable semi-quantitative prior constraints in combination with the transfer function based regularization approach of mHM, can be beneficial for spatial model transferability as the Euclidian distances for the signatures improved on average by 2 %. The effect of semi-quantitative prior constraints combined with topography-guided sub-grid heterogeneity on transferability showed a more variable picture of improvements and deteriorations, but most improvements were observed for low flow statistics.
31
Manies, Kristen L., David J. Mladenoff e Erik V. Nordheim. "Assessing large-scale surveyor variability in the historic forest data of the original U.S. Public Land Survey". Canadian Journal of Forest Research 31, n. 10 (1 ottobre 2001): 1719–30. http://dx.doi.org/10.1139/x01-108.
Testo completoAbstract (sommario):
The U.S. General Land Office Public Land Survey (PLS) records are a valuable resource for studying pre-European settlement vegetation. However, these data were taken for legal, not ecological, purposes. In turn, the instructions the surveyors followed affected the data collected. For this reason, it has been suggested that the PLS data may not truly represent the surveyed landscapes. This study examined the PLS data of northern Wisconsin, U.S.A., to determine the extent of variability among surveyors. We statistically tested for differences among surveyors in recorded tree species, size, location, and distance from the survey point. While we cannot rule out effects from other influences (e.g., environmental factors), we found evidence suggesting some level of surveyor bias for four of five variables, including tree species and size. The PLS data remain one of the best records of pre-European settlement vegetation available. However, based on our findings, we recommend that projects using PLS records examine these data carefully. This assessment should include not only the choice of variables to be studied but also the spatial extent at which the data will be examined.
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Kellner, Olle, e Mickael Mårshagen. "Effects of irrigation and fertilization on the ground vegetation in a 130-year-old stand of Scots pine". Canadian Journal of Forest Research 21, n. 5 (1 maggio 1991): 733–38. http://dx.doi.org/10.1139/x91-104.
Testo completoAbstract (sommario):
Seven years of irrigation and liquid fertilization brought about drastic changes in the vegetation of the field layer (vascular plants) and bottom layer (lichens and mosses) in a mature pine–heath community. Forty new vascular plant species became established. The five most abundant new species had abundant seed sources in the vicinity of the experimental area and were species with effective seed dispersal and (or) a persistent seed bank. Many of the new species, however, dispersed long distances to colonize the experimental area. Wind was the dominant dispersal mechanism among the species that established early, whereas most of the species that established during the later part of the study period had no obvious adaptation for wind or animal dispersal. Two new species with rapid vegetative spread and tall stature, Rubusidaeus L. and Epilobiumangustifolium L., dominated the field layer at the end of the study period. Of the original field layer species, Callunavulgaris (L.) Hull decreased, while the other two dwarf shrubs, Vacciniummyrtillus L. and Vacciniumvitis-idaea L., remained largely constant. The bottom layer as a whole decreased. All reindeer lichens (Cladina spp.) disappeared, and the dominant moss, Pleuroziumschreberi (Brid.) Mitt., decreased markedly. Some new litter-growing moss species became established.
33
Dewar, Bonnie-Kate, John D. Pickard e Barbara A. Wilson. "Behavioural and Psychosocial Outcome Following Vegetative and Minimally Conscious States: Long-Term Follow-Up". Brain Impairment 9, n. 3 (1 dicembre 2008): 267–73. http://dx.doi.org/10.1375/brim.9.3.267.
Testo completoAbstract (sommario):
AbstractThe long-term outcome of persons with impaired consciousness after brain injury remains relatively unclear. The first 12 months post ictus are widely reported as the period of greatest change, with an estimated 20% of persons with traumatic brain injury recovering consciousness. However, beyond 12 months post traumatic and 6 months post-nontraumatic injury the chances of further recovery are thought to diminish significantly. The aim of this study was to investigate the behavioural and psychosocial outcome of 12 patients with impaired consciousness 2 years post ictus. At the time of recruitment five of these patients met the diagnostic criteria defining the vegetative state and seven of these patients met the diagnostic criteria defining the minimally conscious state. Patients were assessed using the Wessex Head Injury Matrix at recruitment and again at least 2 years after initial contact. Functional and psychosocial outcome were also explored. Most patients showed some improvements to their behavioural portfolio, but all were still very dependent physically and all required a high level of support in their activities of daily living. None of the patients had emerged from their original condition, despite exhibiting larger behavioural portfolios. The implications of these findings for the management of patients in low awareness states are discussed.
34
Zanella, Noeli, Almir de Paula, Samara Arsego Guaragni e Leonardo de Souza Machado. "Herpetofauna do Parque Natural Municipal de Sertão, Rio Grande do Sul, Brasil". Biota Neotropica 13, n. 4 (dicembre 2013): 290–98. http://dx.doi.org/10.1590/s1676-06032013000400026.
Testo completoAbstract (sommario):
The northern part of the state of Rio Grande do Sul was extensively deforested in recent decades, and only isolated fragments of the original vegetation remain. The Parque Natural Municipal de Sertão comprises a remnant of Atlantic Rain Forest, one of the largest fragments in northern Rio Grande do Sul. This study examined the diversity of the herpetofauna, focusing on environmental distribution, seasonality and species richness. We used complementary methods of sampling such as pitfall traps, active search and occasional encounters. We recorded 23 species of frogs, nine snakes and one lizard. With respect to the relationship between amphibians and reptiles and the structural and abiotic factors of the environment, the edge of the fragment showed higher richness and increased dominance of amphibians and reptiles than the interior. The highest amphibian abundances were found when the minimum temperatures were higher and maximum temperatures were lower. The abundance of snakes was correlated with humidity, and species richness was influenced by humidity and monthly average temperature. Our results reinforce the importance of the conservation of forested areas to the maintenance of the species
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Kalinina, M. A., e G. N. Schimonova. "P01-303-Vegetative status in infants of high-risk for schizophrenia". European Psychiatry 26, S2 (marzo 2011): 305. http://dx.doi.org/10.1016/s0924-9338(11)72014-4.
Testo completoAbstract (sommario):
IntroductionThe study of clinical features and prognostic significance of autonomic disorders are among the most pressing problems of modern medicine.ObjectivesDynamically within 5 years were observed 50 children at high risk for schizophrenia and 40 children with hypoxic-ischemic encephalopathy of the general population. Aims. Evaluation of prognostic significance of autonomic disorders in infancy for mental health in older age groups.MethodsAll patients were examined by clinical methods and EEG, neurosonografia, original screening tables for early childhood.ResultsIn the first year of life in children at high risk for schizophrenia observed mental and motor development within the syndrome of PDD.In infancy the vagotonic orientation prevailed 72, 5%. By 3 years it changed to the amphotonic orientation reaching 76, 0% of children, while the 10, 0% acquired sympathotony, the rest remained vagotonic.The mental state of 37 children to 5 years qualified as schizotipical disorder (F 21.8). In 13 children it was diagnosed schizophrenia, children's type (F20.8). Frequent and sudden changes in the type of tonus correlated with the deterioration of the mental state of a different nature.In the control group at the first year of life prevailed vagotonic orientation, which gradually to age of one year changed by eutonic. During the first 3–5 months of infancy revealed some unstable circulatory, sleep disorders.ConclusionsThe instability of autonomic tone and an abundance of vegetative violations indicate the risk of mental pathology.
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Cruz, Félix Benjamín. "Responses of two sympatric sand lizards to exotic forestations in the coastal dunes of Argentina: some implications for conservation". Wildlife Research 41, n. 6 (2014): 480. http://dx.doi.org/10.1071/wr14078.
Testo completoAbstract (sommario):
Context Exotic forestations may modify habitat quality, affecting native animal populations that require specific microhabitats to remain viable. Aims We determined whether abundances and body condition of the lizard species Liolaemus wiegmannii and L. multimaculatus differed between forested and non-forested dunes. We also examined what environmental attributes are important in explaining the potential differences. Methods We sampled six sites of 300 ha each. Three of these sites had original vegetation and three were forested with exotic Acacia longifolia. We traced 120 transects per site searching for lizards. Key results Lizards were two times more abundant in non-forested sites than in sites covered by acacia trees (even as low as a fourth of the area). Sites with high densities of acacia (≥78% of coverage) had the lowest abundance of lizards. In forested sites, the snout–vent length of L. wiegmannii was 10% smaller and relative body mass 22% lower than in non-forested sites. We found no differences in the body size of L. multimaculatus. Conclusions The replacement of the native vegetation by A. longifolia has negative effects on lizard species, representing a substantial threat to L. wiegmannii and particularly to L. multimaculatus, a threatened status species. Structural and thermal characteristics of the non-forested sites seemed to be more favourable for the abundance and body condition, whereas the dense vegetation and the low temperatures on the forested sites might explain the lower presence of lizards. Implications We recommend that before the implementation of future forestation plans in the pampasic coastal dunes, the deleterious consequences that this practice generates on native lizard fauna must be considered. When necessary, we recommend that A. longifolia be planted so that the coverage does not exceed a quarter of the total area, so as to prevent the formation of continuous (or closed) forest patches and to maintain the structural heterogeneity of the habitat that these lizards need to survive. In the most affected areas, eradication and control strategies may help reduce the advancement of this exotic plant over the areas intended for conservation.
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Sqalli, M., e H. Chlyah. "Divisions cellulaires au niveau de l'épiderme de l'hypocotyle du lin (Linum usitatissimum) cultivé in vitro". Canadian Journal of Botany 63, n. 10 (1 ottobre 1985): 1691–95. http://dx.doi.org/10.1139/b85-236.
Testo completoAbstract (sommario):
A study of the initiation and propagation of cell divisions in the epidermis of flax hypocotyl segments cultured in vitro was made using surface observations (light and scanning electron microscopes) as well as transverse and longitudinal sections. Epidermal cells were of two types: long, narrow cells and short, wide cells. The latter, less numerous, rarely participated in cell division. Nuclear activation and the first mitoses appeared very early (after 4–8 h of culture). Cell division began in isolated cells and spread progressively to surrounding cells arranged transversely. At 24 h, approximately 50 cells in division or newly divided were observed on an epidermal strip of 10 × 2 mm composed of about 8000 original cells. At 48 h, about 110 cells had divided forming 22 division centers; 26 prophase, 10 metaphase, and 7 telophase figures were observed. The mean number of original cells which participated in the formation of a cell division center was three at 12 h, five at 72 h, with no increase thereafter. The percentage of cells in mitosis or already divided remained low (1.9%) in relation to the total number of epidermal cells. For 22 division centers, only 7 would participate in vegetative bud formation.
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Khafaga, Mounir, Karl-Patrik Kresoja, Berndt Urlesberger, Igor Knez, Philipp Klaritsch, David Benjamin Lumenta, Robert Krause e Dirk von Lewinski. "Staphylococcus lugdunensisEndocarditis in a 35-Year-Old Woman in Her 24th Week of Pregnancy". Case Reports in Obstetrics and Gynecology 2016 (2016): 1–5. http://dx.doi.org/10.1155/2016/7030382.
Testo completoAbstract (sommario):
Background. Infective endocarditis is associated with considerable morbidity and mortality. Guidelines addressing prophylaxis and management of infective endocarditis do not extensively deal with concomitant pregnancy, and case reports on infective endocarditis are scarce. This is the first published report of infective endocarditis byStaphylococcus lugdunensisin a pregnant woman.Case Presentation. We report a single case of a 35-year-old woman in her 24th week of pregnancy who was admitted to our intensive care unit with fever and suspected infectious endocarditis. Blood culture detectedStaphylococcus lugdunensis. A vegetation and severe mitral regurgitation due to complete destruction of the valve confirmed the diagnosis. An interdisciplinary panel of cardiologists, maternal-fetal medicine specialists, cardiac and plastic surgeons, infectiologists, anesthesiologists, and neonatologists was formed to determine the best therapeutic strategy.Conclusions. Timing and indications for surgical intervention to prevent embolic complications in infective endocarditis remain controversial. This original case report illustrates how managing infective endocarditis byStaphylococcus lugdunensisparticularly in the 24th week of pregnancy can represent a therapeutic challenge to a broad section of specialties across medicine. Critical cases like this require a thorough weighing of risks and benefits followed by swift action to protect the mother and her unborn child.
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Harun-Al-Rashid, Ahmed, e Chan-Su Yang. "Improved Detection of Tiny Macroalgae Patches in Korea Bay and Gyeonggi Bay by Modification of Floating Algae Index". Remote Sensing 10, n. 9 (16 settembre 2018): 1478. http://dx.doi.org/10.3390/rs10091478.
Testo completoAbstract (sommario):
This work focuses on the detection of tiny macroalgae patches in the eastern parts of the Yellow Sea (YS) using high-resolution Landsat-8 images from 2014 to 2017. In the comparison between floating algae index (FAI) and normalized difference vegetation index (NDVI) better detection by FAI was observed, but many tiny patches still remained undetected. By applying a modification on the FAI around 12% to 27% increased and correct detection of macroalgae is achieved from 35 images compared to the original. Through this method many scattered tiny patches were detected in June or July in Korea Bay and Gyeonggi Bay. Though it was a small-scale phenomenon they occurred in the similar period of macroalgal bloom occurrence in the YS. Thus, by using this modified method we could detect macroalgae in the study areas around one month earlier than the previously used Geostationary Ocean Color Imager NDVI-based detection. Later, more macroalgae patches including smaller ones occupying increased areas were detected. Thus, it seems that those macroalgae started growing locally from tiny patches rather than being transported from the western parts of the YS. Therefore, this modified FAI could be used for the precise detection of macroalgae.
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Li, Wei, Jiale Jiang, Tai Guo, Meng Zhou, Yining Tang, Ying Wang, Yu Zhang et al. "Generating Red-Edge Images at 3 M Spatial Resolution by Fusing Sentinel-2 and Planet Satellite Products". Remote Sensing 11, n. 12 (14 giugno 2019): 1422. http://dx.doi.org/10.3390/rs11121422.
Testo completoAbstract (sommario):
High-resolution satellite images can be used to some extent to mitigate the mixed-pixel problem caused by the lack of intensive production, farmland fragmentation, and the uneven growth of field crops in developing countries. Specifically, red-edge (RE) satellite images can be used in this context to reduce the influence of soil background at early stages as well as saturation due to crop leaf area index (LAI) at later stages. However, the availability of high-resolution RE satellite image products for research and application globally remains limited. This study uses the weight-and-unmixing algorithm as well as the SUPer-REsolution for multi-spectral Multi-resolution Estimation (Wu-SupReME) approach to combine the advantages of Sentinel-2 spectral and Planet spatial resolution and generate a high-resolution RE product. The resultant fused image is highly correlated (R2 > 0.98) with Sentinel-2 image and clearly illustrates the persistent advantages of such products. This fused image was significantly more accurate than the originals when used to predict heterogeneous wheat LAI and therefore clearly illustrated the persistence of Sentinel-2 spectral and Planet spatial advantage, which indirectly proved that the fusion methodology of generating high-resolution red-edge products from Planet and Sentinel-2 images is possible. This study provided method reference for multi-source data fusion and image product for accurate parameter inversion in quantitative remote sensing of vegetation.
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Watson, James, Alexander Watson, David Paull e David Freudenberger. "Woodland fragmentation is causing the decline of species and functional groups of birds in southeastern Australia". Pacific Conservation Biology 8, n. 4 (2002): 261. http://dx.doi.org/10.1071/pc030261.
Testo completoAbstract (sommario):
The clearance of woodlands and the simultaneous creation of alien environments have been identified as the primary reasons for the decline of many woodland birds in southeastern Australia. This study measured how the size of woodland remnants and habitat structural complexity affected bird composition and distribution in the northern Australian Capital Territory and bordering areas of New South Wales. Within this region only 8% of the original woodlands remain, embedded as patches in a matrix of pasture and suburbia. Woodland birds were surveyed in 72 woodland remnants of different size and vegetation structural complexity. Avifaunal species richness was found to increase with remnant area and habitat complexity (p < 0.01). Of the 31 resident woodland bird species detected, 22 were significantly affected by woodland patch size reduction and 20 species were significantly affected by habitat complexity loss (p < 0.05). Of the species affected, 19 were affected by both reductions in patch size and vegetation complexity. Seven species (Weebill, Brown Thornbill, Buff-rumped Thornbill, Spotted Pardalote, Grey Shrike-thrush, Scarlet Robin and White-winged Chough) not previously identified as threatened by habitat fragmentation occurred significantly less often in small remnants with low habitat complexity. Assessment of avifaunal guilds based on body size and foraging behaviour showed that all large species (n = 4) and 85% (n = 17) of insectivorous species that foraged above the ground were statistically affected by patch size and/or loss of habitat complexity. The occurrence of three species (50%) of granivores was also significantly affected (p < 0.05) by patch size and/or habitat complexity reduction. These results show that the distribution of many bird species, including some considered "common" and "widespread", is affected by patch size and habitat complexity. There are few, large complex woodland remnants within the study area, which continue to reduce in size and complexity. It is therefore predicted that the decline of woodland bird species will continue unless appropriate habitat conservation strategies are applied.
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Tattoni, Clara, Erica Soardi, Filippo Prosser, Maurizio Odasso, Paolo Zatelli e Marco Ciolli. "Fruit availability for migratory birds: a GIS approach". PeerJ 7 (5 febbraio 2019): e6394. http://dx.doi.org/10.7717/peerj.6394.
Testo completoAbstract (sommario):
Bird migration is a widely studied phenomenon, however many factors that influence migratory flows remain unknown or poorly understood. Food availability en route is particularly important for many species and can affect their migration success, pattern and timing but this relationship has not been addressed at a wide scale due to the lack of spatial models of food availability on the terrain. This work presents a GIS-database approach that combines spatial and non-spatial ecological information in order to map fruit availability from vegetation over time in the SE Alps, an important node of European migratory routes. We created a unique database that contains information on the presence and periods of fructification of 52 wild plants carrying berries and a series of original cartographic themes. The presence and coverage of the plant species was modelled with the geo-statistical method of the Gaussian Kernel, which was validated against the ground truth of field sampling data with a correct classification power above 80% in most cases. The highest fruit availability in the study area during September and October co-occurs with the peak of captures of berry eating birds. The maps created and distributed along this work can be useful to address more detailed studies about stopover sites as well as the spatial ecology of other fruit eating animals.
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Ait Hssaine, Bouchra, Olivier Merlin, Jamal Ezzahar, Nitu Ojha, Salah Er-Raki e Said Khabba. "An evapotranspiration model self-calibrated from remotely sensed surface soil moisture, land surface temperature and vegetation cover fraction: application to disaggregated SMOS and MODIS data". Hydrology and Earth System Sciences 24, n. 4 (9 aprile 2020): 1781–803. http://dx.doi.org/10.5194/hess-24-1781-2020.
Testo completoAbstract (sommario):
Abstract. Thermal-based two-source energy balance modeling is essential to estimate the land evapotranspiration (ET) in a wide range of spatial and temporal scales. However, the use of thermal-derived land surface temperature (LST) is not sufficient to simultaneously constrain both soil and vegetation flux components. Therefore, assumptions (about either soil or vegetation fluxes) are commonly required. To avoid such assumptions, an energy balance model, TSEB-SM, was recently developed by Ait Hssaine et al. (2018b) in order to consider the microwave-derived near-surface soil moisture (SM), in addition to the thermal-derived LST and vegetation cover fraction (fc) normally used. While TSEB-SM has been successfully tested using in situ measurements, this paper represents its first evaluation in real life using 1 km resolution satellite data, comprised of MODIS (MODerate resolution Imaging Spectroradiometer) for LST and fc data and 1 km resolution SM data disaggregated from SMOS (Soil Moisture and Ocean Salinity) observations. The approach is applied during a 4-year period (2014–2018) over a rainfed wheat field in the Tensift basin, central Morocco. The field used was seeded for the 2014–2015 (S1), 2016–2017 (S2) and 2017–2018 (S3) agricultural seasons, while it remained unploughed (as bare soil) during the 2015–2016 (B1) agricultural season. The classical TSEB model, which is driven only by LST and fc data, significantly overestimates latent heat fluxes (LE) and underestimates sensible heat fluxes (H) for the four seasons. The overall mean bias values are 119, 94, 128 and 181 W m−2 for LE and −104, −71, −128 and −181 W m−2 for H, for S1, S2, S3 and B1, respectively. Meanwhile, when using TSEB-SM (SM and LST combined data), these errors are significantly reduced, resulting in mean bias values estimated as 39, 4, 7 and 62 W m−2 for LE and −10, 24, 7, and −59 W m−2 for H, for S1, S2, S3 and B1, respectively. Consequently, this finding confirms again the robustness of the TSEB-SM in estimating latent/sensible heat fluxes at a large scale by using readily available satellite data. In addition, the TSEB-SM approach has the original feature to allow for calibration of its main parameters (soil resistance and Priestley–Taylor coefficient) from satellite data uniquely, without relying either on in situ measurements or on a priori parameter values.
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Zhou, An-Pei, Dan Zong, Pei-Hua Gan, Xin-Lian Zou, Xuan Fei, Yuan-Yuan Zhong e Cheng-Zhong He. "Physiological Analysis and Transcriptome Profiling of Inverted Cuttings of Populus yunnanensis Reveal That Cell Wall Metabolism Plays a Crucial Role in Responding to Inversion". Genes 9, n. 12 (23 novembre 2018): 572. http://dx.doi.org/10.3390/genes9120572.
Testo completoAbstract (sommario):
Inverted cuttings of Populus yunnanensis remain alive by rooting from the original morphological apex and sprouting from the base, but the lateral branches exhibit less vigorous growth than those of the upright plant. In this study, we examined the changes in hormone contents, oxidase activities, and transcriptome profiles between upright and inverted cuttings of P. yunnanensis. The results showed that the indole-3-acetic acid (IAA) and gibberellic acid (GA3) contents were significantly lower in inverted cuttings than in upright cuttings only in the late growth period (September and October), while the abscisic acid (ABA) level was always similar between the two direction types. The biosynthesis of these hormones was surprisingly unrelated to the inversion of P. yunnanensis during the vegetative growth stage (July and August). Increased levels of peroxidases (PODs) encoded by 13 differentially expressed genes (DEGs) served as lignification promoters that protected plants against oxidative stress. Kyoto encyclopedia of genes and genomes (KEGG) enrichment analysis showed that most DEGs (107) were related to carbohydrate metabolism. Furthermore, altered activities of uridine diphosphate (UDP)-sugar pyrophosphorylase (USP, 15 DEGs) for nucleotide sugars, pectin methylesterase (PME, 7 DEGs) for pectin, and POD (13 DEGs) for lignin were important factors in the response of the trees to inversion, and these enzymes are all involved cell wall metabolism.
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Infante, Sergio Díaz, Carlos Lara e María del Coro Arizmendi. "Land-Use Change in a Mexican Dry Forest Promotes Species Turnover and Increases Nestedness in Plant-Hummingbird Networks: Are Exotic Plants Taking Over?" Tropical Conservation Science 13 (gennaio 2020): 194008292097895. http://dx.doi.org/10.1177/1940082920978952.
Testo completoAbstract (sommario):
Background Despite the increasing knowledge of plant-pollinator interaction networks, the effects of human-induced disturbances on them have barely been studied. We analyzed whether land-use changes modified the structure and topology of plant-hummingbird interaction networks or promoted the integration of exotic plant species. Methods Fieldwork was carried out in two vegetation areas in Mexico: a protected tropical dry forest and nearby disturbed sites. For two years we registered hummingbird-plant interactions monthly in each area. Then, we constructed interaction matrices from these data and compared their assemblage structure. Results The conversion of original dry forest to disturbed habitats impacted some assemblage attributes of the plant-hummingbird network. In the disturbed sites, there were more plant species, mainly exotics, and one additional hummingbird species. Most network attributes remained the same except niche width and nestedness (pattern of interactions where generalists and specialists tend to interact with generalists whereas specialist-to-specialist interactions are infrequent), which were higher in the disturbed network. The generalist core in the disturbed network contained half of the core species in the conserved network. Implications for conservation Exotic plants that strongly integrated into the disturbed network may exert a large influence on network dynamics in these areas. Identifying the interacting species and their role provides valuable insights for their conservation and protection. Hummingbirds attracting native plant species have a potential for practical or ornamental use, and hummingbirds presence in human-modified landscapes not only provides positive aesthetic value to people but can additionally contribute to conserving native plants and the biodiversity associated with them.
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Marić, Mara, e Ivana Vitasović-Kosić. "Horticultural species of the island of Lokrum in the period of archduke Maximilian of Habsburg (1859–1869) and their current state". Šumarski list 144, n. 9-10 (27 ottobre 2020): 443–54. http://dx.doi.org/10.31298/sl.144.9-10.1.
Testo completoAbstract (sommario):
This research, conducted within the ornamental gardens of the Island of Lokrum and based on the original archival documents from Trieste State Archives (AST) and Austrian State Archives (OeStA) in Vienna, was aimed at creating the first unique list of horticultural plant taxon planted on the island during the reign of the Archduke Ferdinand Maximilian Habsburg (1859-69). The research identified 213 taxa, including 184 species, 4 varieties, 8 hybrids and 17 cultivars. There were 193 allochthonous taxa, mostly originating from Central and South America (66), including 47 Asian species, 21 Australian species, 17 African species and 13 South American species. The Archive lists 20 taxa autochthonous in Croatia. While the number of the autochthonous taxa had apparently been higher, the historical documents have mostly recorded only the introduction of exotics. At that time, the following taxa were for the first time introduced in this part of the Adriatic, on the Island of Lokrum: Ananas comosus, Musa x paradisiaca, M. acuminata, Eucalyptus diversifolia, E. globulus, Araucaria araucana, A. columnaris, A. angustifolia, A. bidwillii, A. cunninghamii, Bougainvillea spectabilis and Citrus reticulata. At the location of the ornamental gardens, 51 ornamental allochthonous taxa and 20 autochthonous taxa were identified today. Within this number, only 21 allochthonous taxa and 9 autochthonous taxa remain present since the period of Maximilian. According to the 2018-2019 inventory, 71 taxa have been inventoried within the ornamental gardens on Lokrum, belonging to 43 families and 64 genera. Due to lack of intensive maintenance of the gardens, the majority of allochthonous, exotic species failed to survive within the autochthonous island vegetation. The list of taxa from Maximilian’s gardens presented in this paper and retrieved from the archival sources, will be the starting point of the restoration process that awaits these gardens.
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Enya, J., M. Togawa, T. Takeuchi, S. Yoshida, S. Tsushima, T. Arie e T. Sakai. "Biological and Phylogenetic Characterization of Fusarium oxysporum Complex, Which Causes Yellows on Brassica spp., and Proposal of F. oxysporum f. sp. rapae, a Novel Forma Specialis Pathogenic on B. rapa in Japan". Phytopathology® 98, n. 4 (aprile 2008): 475–83. http://dx.doi.org/10.1094/phyto-98-4-0475.
Testo completoAbstract (sommario):
Although the causal agent of yellows of Brassica rapa (turnip, pak choi, and narinosa) in Japan was reported in 1996 to be Fusarium oxysporum f. sp. conglutinans, this classification has remained inconclusive because of a lack of detailed genetic and pathogenic studies. Therefore, we analyzed the taxonomic position of this organism using Japanese isolates of F. oxysporum complex obtained from diseased individuals of various B. rapa subspecies. Phylogenetic analyses using partial sequences of the rDNA intergenic spacer region and the mating-type gene (MAT1-1-1α-box) showed that B. rapa and cabbage isolates belong to different monophyletic clades that separated at early evolutionary stages. Additionally, correlations were observed between the molecular phylogeny and the vegetative compatibility groups. Isolates from turnip, komatsuna, and narinosa (B. rapa group) did not show pathogenicity against cabbage or broccoli (B. oleracea group), although they caused severe symptoms on their original host species. In contrast, cabbage isolates had significantly higher (P = 0.05) virulence on B. oleracea than on B. rapa crops. Our results indicate that F. oxysporum complex isolates from B. rapa and B. oleracea are not only phylogenetically distinct but also differ in host specificity. Therefore, we propose a novel forma specialis, F. oxysporum f. sp. rapae, which causes yellows on B. rapa, including turnip, komatsuna, pak choi, and narinosa.
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Stuepp, Carlos André, Katia Christina Zuffellato-Ribas, Henrique Soares Koehler e Ivar Wendling. "ROOTING MINI-CUTTINGS OF Paulownia fortunei var. mikado DERIVED FROM CLONAL MINI-GARDEN1". Revista Árvore 39, n. 3 (giugno 2015): 497–504. http://dx.doi.org/10.1590/0100-67622015000300010.
Testo completoAbstract (sommario):
ABSTRACTWe aimed to evaluate the technical efficiency of mini-cuttings technique on vegetative propagation of Paulownia fortunei (Seem.) Hemsl. var. Mikado, as well as the possible existence of anatomical barriers to its rooting. Therefore, plants originated from cuttings formed the mini-stumps and, consequently the clonal mini-garden, which was conducted in semi-hydroponic system. We evaluated the survival of mini-stumps and sprouts production for five successive collects, the percentage of mini-cuttings rooting and their anatomical description. The mini-cuttings were prepared with about 6 to 8 cm in length and two leaves reduced by about 50% in the upper third, being remained an area of, approximately 78 cm2 (10 cm diameter). The mini-cuttings were placed in tubes of 53 cm3, with substrate formed with fine vermiculite and carbonized rice hulls (1:1 v/v) and rooted in acclimatized greenhouse. After 30 days we evaluated the percentage of rooted mini-cuttings, radicial vigor (number and length of roots / mini-cutting), callus formation, emission of new shoots and maintenance of the original leaves. The mini-stumps showed 100% survival after five collects and an average production of 76-114 mini-cuttings/m2/month and rooting ranged from 70 to 90%. Mini-cuttings technique is efficient in to propagate adult propagules of the species and there are not anatomical barriers preventing roots emission.
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Na, Zhao, Wang Zhengwen, Shao Xinqing e Wang Kun. "Diversity components and assembly patterns of plant functional traits determine community spatial stability under resource gradients in a desert steppe". Rangeland Journal 38, n. 5 (2016): 511. http://dx.doi.org/10.1071/rj15094.
Testo completoAbstract (sommario):
The diversity–stability relationship has been addressed and debated for decades, but how this relationship is affected by nutrient availability remains contentious. In the present study we assessed the effects of plant diversity, in terms of species richness, functional group composition and functional trait diversity, on the spatial stability of net primary productivity (NPP) following nitrogen and phosphorus application. In addition, we explored how functional traits at the species level contribute to the spatial stability of NPP. The results support the hypothesis that greater diversity leads to higher spatial stability. This relationship was highly dependent on soil nutrient availability, and increasing species richness or functional trait diversity significantly increased spatial variation of NPP under a high N fertilisation level. The effects of high mineral fertilisation rates may perhaps have masked the effects of plant diversity. Although species richness or functional trait diversity of the original and modified communities from which species with particular functional traits had been removed were significantly different, there were no differences in the coefficients of variation in the NPP of those communities. The lack of difference demonstrated that the relationship between spatial variability and biodiversity depended on the measure of diversity applied and that the functional group composition exerted a stronger effect than other diversity measures. Further analyses revealed that spatial stability of NPP was enhanced with increased diversity in vegetative plant height, rooting depth and the presence of legume, and diminished with diversity in the root system type and life cycle under some fertilisation treatments. The present study demonstrates that the relationship between biodiversity and ecosystem functioning is variable with different diversity, identity and environmental factors. Evaluating the contribution of particular traits to community stability will ultimately help us better understand the mechanisms underlying the diversity–stability relationship.
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Gilta, J., e J. R. J. Van Asperen De Boer. "Een nader onderzoek van 'De drie Maria's aan het H. Graf' - een schilderij uit de 'Groep Van Eyck' in Rotterdam". Oud Holland - Quarterly for Dutch Art History 101, n. 4 (1987): 254–75. http://dx.doi.org/10.1163/187501787x00484.
Testo completoAbstract (sommario):
AbstractThe precise relationship of The Three Maries at the Tomb (Fig. 1) in the Boymansvan Beuningen Museum in Rotterdam to the work of Hubert and/or Jan van Eyck has proved difficult to establish, mainly because relatively little is known about their output apart from Jan van Eyck's signed paintings of 1432-41. The provenance of the Rotterdam picture has been traced back to the mid 18th century (Note 2), while the coat of arms, a later addition at bottom right, has been identified as that of Philippe de Commines, who has thus been posited as the earliest known owner (Note 3). Since the beginning of this century the panel has generally been ascribed to Hubert van Eyck on the basis of a comparison with his contribution to the Ghent Altarpiece, but doubts have also been expressed about the attribution to the Van Eycks (Note 5), while later dates have been suggested on the grounds of the view of Jerusalem (Note 6, 7) or the arms and armour (Notes 8, 9) . However, Panofsky remained convinced of the early date and kept to the attribution to Hubert, while suggesting that Jan had worked over certain details (Note 10). The restoration of 1947 (Note 11) revealed some gilded rays on the right side, which gave rise to suggestions that the panel had once formed part of a friezelike composition or a triptych (Notes 12-14). Recent opinion still remains divided, Sterling seeing the panel as having been painted by Jan van Eyck after 1426 (Note 15), Dhanens as the work of a follower around 1450-60 (Note 16). Scientific examination appeared to be the only way of obtaining new data, while the recently published results of a similar examination of the Ghent Altarpiece (Note 17) offered an additional incentive. An earlier scientific examination was carried out by Coremans in 1948 (Note rg), while the work had previously been examined by infrared reflectography by the authors in 1971 (JV ote zo) . Tfie 1)(inel on which the picture is painted consists rf three horizontal planks with dowelled joints (Note 21). The four corners are bevelled off at the back, which suggests that any later reduction in the panel can only have been slight. On the back is a sealed statement by D. G. van Beuningen to the effect that the painting had not suffered from being stored underground during the war (Fig. 2, Appendix 2) . The paint surface is in a reasonably good state, but exhibits heavy craquelure, which has played a part in the aesthetic assessment of the picture (Note 23) . Dendrochronological examination (Appendix I) showed that the two oaks from which the planks came were probably not felled before 1423. Since recent research has shown that the gap between felling and usage was not likely to have been much more than fifteen years in the 15th century (Note 25) and there is nothing to support the hypothesis that an old panel was reused here (Note 26), it is highly improbable that the picture was painted at the end of the 15th century. The most likely date is C. 1425-35 i.e. the period when the Ghent Altarpiece was painted or slightly later. No other results of dendrochronological examination on Van Eyck panels are available for comparison as yel. Examination by infrared reflectography (Note 28) revealed detailed underdrawing in virtually all parts of the picture and this was very carefully followed during painting with changes only in small details (cf. Figs.3, 5, 7). Stylistically the underdrawing accords with what is known about underdrawing in Van Eyck paintings today, this exhibiting a considerable difference from that of other Flemish Primitives, so that the Rotterdam panel is certainly a Van Eyck work. Among the most striking similarities to the central panel (x) and that with the Knights of Christ (IX) in the Ghent Altarpiece (Note 30) are the underdrawing of the drapery of the angels (Figs. 7-9), the city in the distance (Figs. 3,4, Note 31) and the minutely detailed armour (Figs. 14, 15, Note 33). Types of hatching that appear to be characteristic of the Van Eyck style are that of the shadows, which is sometimes overlapping and generally parallel to the main contours (Figs. 5,8) and a more rarely used type with short lines at an angle to contours (Fig. 9). The x-radiographs (Note 35) give a good idea of the damage to the paint surface (Figs. 16, 17) , which isfound mainly in the sky, along the crack in the top plank and on the bottom edge on the left. There is also a great deal of abrasion on the edges of the craquelure. The x-radiographs confirm the fact that no radical changes were made in the original, generally underdrawn, composition and reveal that the soldiers and their arms were left in reserve during the painting of the rocks and ground, a detail which likewise indicates continuity during the painting process. The underpainting of the rocks in large light blocks with simple contours shown up by x-ray photography is very close to that in panel IX in the Ghent Altarpiece (Note 38). Examination by stereomicroscope (Note 40) generally already gave an impression of the layered structure of the paint. It also showed up some minute details scarcely distinguishable by the naked eye : two horsemen and somefigures in tlae square on tlte leji qlthe city, a .slalue in a niche in the doorway in the zvall in tlae certtre (Fig. 18; possibly a reminiscence of the Golden Gate, Note 56) and a number of ship's masts with crow's nests on the horizon on the right (Fig. 19). Part of the vegetation was shown to be very finely and precisely rendered (Figs. 20, 21), while the rest was not so fine. Similar differences appear in the two bronze-coloured ointment jars in this painting and also in the bottom zone of the Ghent Altarpiece (Note 41). These may reveal two different hands or the somewhat hasty finishing of some areas. The paint samples (Note 42) revealed the presence of an oleaginous isolating layer over the chalk and glue ground comparable to, but thinner than that on the Ghent Altarpiece (Note 45). The only other Flemish Primitive in whose work such a layer is found is Dirc Bouts (Note 50). The paint layer also exhibits many similarities to that of the Ghent Altarpiece, not only in the number and thickness of the layers, but in the composition and overall structure of the paint. For example, the skies in both works are built up in three layers from light to dark on the basis of lead white with increasing amounts of azurite and sometimes a bit of lapis lazuli, the vegetation consists of two layers of green with a glaze over them and the structure of the red mantle of one of the Maries resembles similar areas in the Ghent Altarpiece. This technique again makes it very unlikely that the panel was painted at the end of the 15th century or later. A final point is that the gilded rays ( Fig. 22), like the coat of arms (Fig. 23), prove to be a later addition. Finally, renewed consideration was given to certain iconographical aspects which have been used as dating criteria. The arms and armour have been seen as grounds for a later dating by Squilbeck in particular, but it seems quite likely that many of the forms are purely imaginary, while other experts do not agree with Squilbeck in dating certain elements to the 16th century (Note 53). The arms and armour are in any case an integral part of the painting. The detailed view of Jerusalem is regarded by some as impossible before Erhard Reuwich's print of 1486, while others express surprise that it was not copied by other artists. In fact, however, it is strikingly close in many details to the view in the Ghent Altarpiece, although the latter is firmer in its spatial construction and more convincing. Whole sentences have been read into the texts on the hems of two of the Maries' garments and the soldier's cap (Note 57 ) and it has been argued that the letters are Roman, not Hebrew (Note 58), but in fact they are indispulably Hebrew and although words can sometimes be recognized, they do no form a sentence or text (Note 59). The coat of arms is certainly that of a nobleman of the Order of St. Michael, but whether he was Philippe de Commines is uncertain. The Van den Woesteyne and Van Meaux van Vorsselaer families also bore these arms, albeit in different tinctures (Note 6o). Since the arms are done, in a brownish-grey, they cannot be more precisely identified. The presence of no less than five layers of varnish between the green meadow and the coat of arms could indicate that the arms were added much later than previously thought, possibly in the 16th or even the 17th century (Note 47). While the present study has shown that the Rotterdam painting is quite an early Van Eyck, its precise position in the Van Eyck oeuvre cannot be determined until results of examinations of other works in the group are available.