Entity

Time filter

Source Type

International Falls, United States

Perosa M.,National University of Cuyo | Rojas F.,CONICET | Villagra P.,CONICET | Villagra P.,National University of Cuyo | And 4 more authors.
Ecologia Austral | Year: 2014

In arid areas of Argentina, Prosopis flexuosa woodlands are of foremost importance since they are thought to protect the soil against erosion in a region with a high risk of desertification, and because they offer several resources to local inhabitants, such as firewood, forage for cattle, and food products derived from its fruit. These woodlands have been strongly impacted by human activities, mainly during the first half of the XIXth century. Knowledge about their potential distribution, as well as a comparison between potential and actual distributions, would allow priority areas for conservation and possible areas for reforestation to be defined. The aim of this work was to generate a model of the potential distribution of P. flexuosa woodland within a region of arid shrub lands in central Argentina, known as the Monte desert. Maxent software was used to generate the distribution models. The software uses as input a set of georeferenced data of the presence of P. flexuosa woodland, and of those relevant for the distribution of species (e.g., climatic, altitude, slope, aspect, soil and water table depth). The resulting potential distribution model generally coincided with the main valleys, depressions and plains of the region, where P. flexuosa woodland are known to exist currently. However, area and limits of observed and estimated woodland patches differ in some cases, which could be related with anthropogenic disturbances in some of the patches or with variables not included in the model, such as the probability of wildfires. Source


Tognelli M.F.,IUCN CI Biodiversity Assessment Unit | Tognelli M.F.,CONICET | Abba A.M.,National University of La Plata | Bender J.B.,National University of Cuyo | Seitz V.P.,CONICET
Biodiversity and Conservation | Year: 2011

In this study, we combine species distribution models with a reserve selection approach to assess the degree of representation of xenarthrans in the existing protected area network of Argentina, and to identify conservation priority areas that may help expand the current system. Species distribution models were developed from species' occurrence records using a maximum entropy algorithm. Maps of species distributions were produced for 15 of the 16 species currently present in the country. To assess the performance of the existing protected area network in representing all modeled species, and to identify priority areas to expand the current reserve system, we used the software Zonation. Overall, all species modeled are represented in the existing protected area network. However, the percentage of their ranges covered by protected areas is very low (average = 6.7%; range = 1.7-17.6%). To represent at least 5% of the distribution of each species, 8.8% of the country's area would be needed, and species with restricted ranges have the greatest increase in representation in this scenario. When 10% of the country is set aside for conservation, species representation increases considerably, again favoring range-restricted species. Most of the areas identified as conservation priorities are under strong anthropogenic pressures, including deforestation, agricultural expansion, and hunting. Our analysis provides a preliminary assessment of conservation priorities for the xenarthrans of Argentina, and we hope will serve as guideline to focus future conservation assessments at more refined scales. © 2010 Springer Science+Business Media B.V. Source


Rondinini C.,University of Rome La Sapienza | di Marco M.,University of Rome La Sapienza | Chiozza F.,University of Rome La Sapienza | Santulli G.,University of Rome La Sapienza | And 18 more authors.
Philosophical Transactions of the Royal Society B: Biological Sciences | Year: 2011

Detailed large-scale information on mammal distribution has often been lacking, hindering conservation efforts. We used the information from the 2009 IUCN Red List of Threatened Species as a baseline for developing habitat suitability models for 5027 out of 5330 known terrestrial mammal species, based on their habitat relationships. We focused on the following environmental variables: land cover, elevation and hydrological features. Models were developed at 300 m resolution and limited to within species' known geographical ranges. A subset of the models was validated using points of known species occurrence. We conducted a global, fine-scale analysis of patterns of species richness. The richness of mammal species estimated by the overlap of their suitable habitat is on average one-third less than that estimated by the overlap of their geographical ranges. The highest absolute difference is found in tropical and subtropical regions in South America, Africa and Southeast Asia that are not covered by dense forest. The proportion of suitable habitat within mammal geographical ranges correlates with the IUCN Red List category to which they have been assigned, decreasing monotonically from Least Concern to Endangered. These results demonstrate the importance of fine-resolution distribution data for the development of global conservation strategies for mammals. © 2011 The Royal Society. Source


Jenkins R.K.B.,Global Species Programme | Tognelli M.F.,IUCN CI Biodiversity Assessment Unit | Bowles P.,IUCN CI Biodiversity Assessment Unit | Cox N.,IUCN CI Biodiversity Assessment Unit | And 38 more authors.
PLoS ONE | Year: 2014

Background: An understanding of the conservation status of Madagascar's endemic reptile species is needed to underpin conservation planning and priority setting in this global biodiversity hotspot, and to complement existing information on the island's mammals, birds and amphibians. We report here on the first systematic assessment of the extinction risk of endemic and native non-marine Malagasy snakes, lizards, turtles and tortoises. Methodology/ Principal Findings: Species range maps from The IUCN Red List of Threatened Species were analysed to determine patterns in the distribution of threatened reptile species. These data, in addition to information on threats, were used to identify priority areas and actions for conservation. Thirty-nine percent of the data-sufficient Malagasy reptiles in our analyses are threatened with extinction. Areas in the north, west and south-east were identified as having more threatened species than expected and are therefore conservation priorities. Habitat degradation caused by wood harvesting and non-timber crops was the most pervasive threat. The direct removal of reptiles for international trade and human consumption threatened relatively few species, but were the primary threats for tortoises. Nine threatened reptile species are endemic to recently created protected areas. Conclusions/Significance: With a few alarming exceptions, the threatened endemic reptiles of Madagascar occur within the national network of protected areas, including some taxa that are only found in new protected areas. Threats to these species, however, operate inside and outside protected area boundaries. This analysis has identified priority sites for reptile conservation and completes the conservation assessment of terrestrial vertebrates in Madagascar which will facilitate conservation planning, monitoring and wise-decision making. In sharp contrast with the amphibians, there is significant reptile diversity and regional endemism in the southern and western regions of Madagascar and this study highlights the importance of these arid regions to conserving the island's biodiversity. © 2014 Jenkins et al. Source


Meng H.,United Nations Environment Programme World Conservation Monitoring Center | Carr J.,IUCN Species Survival Commission Climate Change Specialist Group | Beraducci J.,MBT snake farm | Bowles P.,IUCN CI Biodiversity Assessment Unit | And 17 more authors.
Biological Conservation | Year: 2016

Assessments of biodiversity patterns and threats among African reptiles have lagged behind those of other vertebrate groups and regions. We report the first systematic assessment of the distribution, threat status, and climate change vulnerability for the reptiles of Tanzania. A total of 321 reptile species (including 90 Tanzanian endemics) were assessed using the global standard IUCN Red List methodology and 274 species were also assessed using the IUCN guidelines for climate change vulnerability. Patterns of species richness and threat assessment confirm the conservation importance of the Eastern Arc Mountains, as previously demonstrated for birds, mammals and amphibians. Lowland forests and savannah-woodland habitats also support important reptile assemblages. Protected area gap analysis shows that 116 species have less than 20% of their distribution ranges protected, among which 12 are unprotected, eight species are threatened and 54 are vulnerable to climate change. Tanzania's northern margins and drier central corridor support high numbers of climate vulnerable reptile species, together with the eastern African coastal forests and the region between Lake Victoria and Rwanda. This paper fills a major gap in our understanding of the distribution and threats facing Tanzania's reptiles, and demonstrates more broadly that the explicit integration of climate change vulnerability in Red Listing criteria may revise spatial priorities for conservation. © 2016 Elsevier Ltd. Source

Discover hidden collaborations