Suchergebnisse

Context
Tropical ecosystems are widely recognised for their high species richness and outstanding concentrations of rare and endemic species. Previous studies either focussed on the effects of deforestation or climate change, whereas studies on the combined effects of these two major threats are limited.

Aims
This research aimed to model current and future distributions of medium- to large-sized mammal species on the basis of different land-use and climate-change scenarios in 2050 and to assess whether the predicted effects of land-use change are greater than those of climate change and whether the combined effects of these drivers are greater than those of either individual driver.

Methods
The present article demonstrates a method for combining nationwide wildlife-inventory data, spatially explicit species-distribution models, current and predicted future bioclimatic variables, other biophysical factors and human disturbance to map distributions of mammal species on the basis of different land-use and climate-change scenarios and to assess the role of protected areas in conservation planning.

Key results
Seventeen medium- to large-sized mammal species were selected for modelling. Most selected species were predicted to lose suitable habitat if the remaining forest cover declines from the current level of 57% to 50% in 2050. The predicted effects of deforestation were stronger than the effects of climate change. When climate and land-use change were combined, the predicted impacts were more severe. Most species would lose suitable habitat and the average shift in species distribution was greater than 40%.

Conclusions
The predicted effects were positive for only a few species and negative for most species. Current and future centres of mammal-species richness were predicted in large and contiguous protected forests and the average contribution of existing and proposed protected areas in protecting the focal species will increase from 73% to 80% across all scenarios.

Implications
The present research advances the current understanding of the ecology of 17 medium- to large-sized mammal species with conservation relevance and the factors that affect their distributions at the landscape scale. In addition, the research demonstrated that spatially explicit models and protected areas are effective means to contribute to protection of mammal species in current and future land-use and climate-change scenarios.

"This book combines state-of-the-art modeling approaches at various scales with case studies from across the world, discussing how to translate models into results and illustrate how pro-active implementation can mitigate biodiversity loss"--Provided by publisher

Context. Assessing the viability of animal populations in the wild is difficult or impossible, primarily because of limited data. However, there is an urgent need to develop methods for estimating population sizes and improving the viability of target species.
Aims. To define suitable habitat for sambar (Cervus unicolor), banteng (Bos javanicus), gaur (Bos gaurus), Asian elephant (Elephas maximus) and tiger (Panthera tigris) in the Western Forest Complex, Thailand, and to assess their current status as well as estimate how the landscape needs to be managed to maintain viable populations.
Methods. The present paper demonstrates a method for combining a rapid ecological assessment, landscape indices, GIS-based wildlife-habitat models, and knowledge of minimum viable population sizes to guide landscape-management decisions and improve conservation outcomes through habitat restoration.
Key results. The current viabilities for gaur and elephant are fair, whereas they are poor for tiger and banteng. However, landscape quality outside the current distributions was relatively intact for all species, ranging from moderate to high levels of connectivity. In addition, the population viability for sambar is very good under the current and desired conditions.
Conclusions. If managers in this complex wish to upgrade the viabilities of gaur, elephant, tiger and banteng within the next 10 years, park rangers and stakeholders should aim to increase the amount of usable habitat by ~2170 km2 or 17% of existing suitable habitats. The key strategies are to reduce human pressures, enhance ungulate habitats and increase connectivity of suitable habitats outside the current distributions.
Implications. The present paper provides a particularly useful method for managers and forest-policy planners for assessing and managing habitat suitability for target wildlife and their population viability in protected-area networks where knowledge of the demographic attributes (e.g. birth and death rates) of wildlife populations are too limited to perform population viability analysis.