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The Man and Biosphere Program of UNESCO (MAB) was a pioneer in recognizing the role of local communities in the conservation of biodiversity. Biosphere reserves of MAB were designed with a core zone with maximum protection, a buffer zone with regulated activities, and a transition zone outside the reserve proper. The transition zone is where experimental management options to promote sustainable development could be developed, and could add value to the conservation network and to regional activities. The Nilgiris Biosphere Reserve (NBR), with a core zone of 1,240 km2 and a buffer zone of 4,280 km2, was created in 1986 without a transition zone. The absence of a transition zone separates the protected areas (PAs) from each other, and the hard boundary between the PA and surrounding areas promotes human-wildlife conflict and encourages development inimical to the mandate of the Biosphere Reserve, ultimately affecting the regional economy through progressive degradation of the environment. We examine three case studies to illustrate these concerns: the implementation of the India-based Neutrino Observatory, resistance by tourist resorts against regulations for connecting elephant corridors, and whether the goals of local tourism operators meet the conservation objectives of the NBR. Landscape ecology and econometry can help design a transition zone on a sound economic basis. A better environment management is within technical and financial reach. But is it within political reach?
Brazil is the country with the most biodiversity in the world and also hosts the largest rainforest on the planet. Although Brazil was a pioneer of public policies for conservation of biodiversity and natural resources, it has recently jeopardized all biome conservation through questionable environmental policies. Over the past four years, the government has drastically altered its environmental legislation, removing vast areas from protection and encouraging overexploitation of natural resources, which will result in loss of biodiversity, reduction of forest cover, and increased pollution of soil and water. The Brazilian political-social scene and its relationship with biodiversity conservation are discussed as well.
Amazon floodplains have a long history of exploitation of crocodilians, particularly of large species such as the black caiman (Melanosuchus niger) and spectacled caiman (Caiman crocodilus). Historically, legal but uncontrolled trade resulted in a drastic reduction of wild populations of both species, which eventually led to the collapse of the commercial trade. In 1967, prohibition of commercial use of wild fauna through changes in Brazilian and international laws allowed caiman populations to slowly recover across much of their original range. Several studies on caiman populations greatly improved knowledge about the species, offering scientific bases for crocodilian management in the wild. Although protective legislation should only be altered using extreme caution, the creation of Sustainable Development Reserves (SDR) at the end of last century made it possible to manage wildlife for commercial purposes, albeit under strict population monitoring regimes. This category of protected area was established to improve welfare of local communities and strengthen their participation in conservation. Along with involvement in caiman monitoring programs, the engagement of local hunters and buyers is essential for participatory management plans. Even with development of SDRs, monitoring of crocodilian populations is still restricted to a few State Reserves, and traditional knowledge of stakeholders has been insufficiently incorporated into management and monitoring activities. We believe that stronger participation of local actors can help to improve the experimental harvesting initiatives that have been carried out thus far by local authorities. Community-based monitoring programs, which reflect local reality, are being developed in a simple and cost-effective way.
The question whether animal populations are top-down and/or bottom-up controlled has motivated a thriving body of research over the past five decades. In this review I address two questions: 1) how do top-down and bottom-up controls influence large herbivore populations? 2) How do human activities and control systems influence the top-down and bottom-up processes that affect large herbivore population dynamics? Previous studies suggest that the relative influence of top-down vs. bottom-up control varies among ecosystems at the global level, with abrupt shifts in control possible in arid and semi-arid regions during years with large differences in rainfall. Humans as super-predators exert top-down control on large wild herbivore abundances through hunting. However, through fires and livestock grazing, humans also exert bottom-up controls on large wild herbivore abundances through altering resource availability, which influences secondary productivity. This review suggests a need for further research, especially on the human-induced top-down and bottom-up control of animal populations in different terrestrial ecosystems.
Conservation of natural ecosystems requires regular monitoring of biodiversity, including the estimation of wildlife density. Recently, unmanned aerial systems (UAS) have become more available for numerous civilian applications. The use of small drones for wildlife surveys as a surrogate for manned aerial surveys is becoming increasingly attractive and has already been implemented with some success. This raises the question of how to process UAS imagery in order to determine the surface area of sampling strips within an acceptable confidence level. For the purpose of wildlife surveys, the estimation of sampling strip surface area needs to be both accurate and quick, and easy to implement. As GPS and an inertial measurement units are commonly integrated within unmanned aircraft platforms, two methods of direct georeferencing were compared here. On the one hand, we used the image footprint projection (IFP) method, which utilizes collinearity equations on each image individually. On the other hand, the Structure from Motion (SfM) technique was used for block orientation and georeferencing. These two methods were compared on eight sampling strips. An absolute orientation of the strip was determined by indirect georeferencing using ground control points. This absolute orientation was considered as the reference and was used for validating the other two methods. The IFP method was demonstrated to be the most accurate and the easiest to implement. It was also found to be less demanding in terms of image quality and overlap. However, even though a flat landscape is the type most widely encountered in wildlife surveys in Africa, we recommend estimating IFP sensitivity at an accentuation of the relief.
An ethnobiological survey of 174 local resource users was conducted in the Lower Sanaga Basin to assess the current conservation status of West African manatee (Trichechus senegalensis, Link 1795) within lakes, rivers, and coast (including mangroves, estuaries and lagoons). Using a multistage sampling design with semi-structured interviews, the study asked three main questions: (i) are manatees still present in Lower Sanaga Basin? (ii) If present, how are their numbers evolving with time? (iii) What are the main threats facing the manatee? Each of these questions led to the formulation and formal testing of a scientific hypothesis. The study outcome is as follows: (i)60% of respondents sighted manatees at least once a month, regardless of habitat type (rivers, lakes, or coast) and seasons (dry, rainy, or both); (ii) depending on habitat type, 69 to 100% of respondents perceived the trend in manatee numbers as either constant or increasing; the increasing trend was ascribed to low kill incidence (due either to increased awareness or lack of adequate equipment) and to high reproduction rate; and (iii) catches (directed or incidental) and habitat degradation (pollution) ranked in decreasing order as perceived threats to manatees. The catch incidence is threefold larger on lakes than in rivers and more adult manatees are caught than juveniles. Pollution occurs in several places by fishing enterprises, industrial plantations and individuals. The perceived incidence of boat collisions is presently negligible compared to catches and habitat degradation. A twelve-point strategy is set forth for improving manatee conservation in the study area.
In the northernmost American tropical forests of eastern Mexico, we analyzed the potential distribution of three ungulate species, Odocoileus virginianus, Mazama temama and Pecari tajacu, in response to several physical, climatic, biological, and anthropogenic variables, in order to identify environmental factors affecting distribution and potential key areas for ungulate conservation. Current presence records for these species were gathered, and potential distribution models were built using Maximum Entropy niche modeling (MaxEnt). Model suitability surfaces were used to calculate remaining potential habitat areas in the region, as well as the potential sympatric area and representation of these areas in Natural Protected Areas. Biological and anthropogenic variables were the best species distribution predictors. Landscape composition (the proportion of different land-use and land-cover classes: forest, agriculture, and pasture) within approximately 120 ha, was the most important variable for all models, influencing each species differently with respect to their tolerance of altered habitats. The remaining potential area of all three species is fragmented and has apparently been nearly lost in plains (<14% remaining). Distribution models allowed us to detect an important location in the western portion of our study area which may function as a large biological corridor in the Sierra Madre Oriental mastogeographic province, a region heavily transformed by land use change. In the context of habitat transformation, management promoting quality matrix at the landscape level promises to be a viable alternative for ungulate conservation in tropical regions of Mexico.
More than one fifth of the world's mammals are listed in an extinction risk category. However, extinction risk should not be the only criterion used in conservation prioritization schemes. Here, we used a species and spatial prioritization scheme for the conservation of Brazilian mammals that incorporates other parameters in addition to extinction risk. Our results suggest that 3.4% of all Brazilian mammal species are high priorities and 29.1% of all Brazilian ecoregions are also high priorities. Since 62.5% of the species identified as high-priority do not have any national conservation plan, we hope our results will help guide mammal conservation actions.
Large mammals are elusive, often nocturnal, and therefore difficult to study. In many parks, reserves, agriculture lands, and other human-dominated landscapes, mammalian abundance is unknown despite their importance to ecosystems. The Río Plátano Biosphere Reserve of eastern Honduras has been the site of much research, but many rivers within the reserve have not been surveyed for mammalian diversity. In this study we used camera traps to survey an area of 70 km2 along the Sikre River for mammals in both broad-leaf forest and pine savanna. 2,040 trap-nights yielded 116 captures in total. Fourteen mammal, three bird, and one reptile species were photographed in the broad-leaf forest, while none of the four camera stations in the pine savanna captured animals on film. The tapir (Tapirus bairdii) was the most frequently captured species. We also captured four photographs of at least two individuals of the giant anteater (Myrmecophaga tridactyla), a species considered the most threatened mammal in Central America. Of the felids, Puma concolor and Leopardus pardalis were each captured on five photographs each, while Panthera onca was only captured once during a preliminary pilot survey in 2007. The results suggest the study site hosts a species richness of large- and medium-sized mammals that is comparable to other sites in Central and South America.
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