Assessing Conservation Values: Biodiversity and Endemicity in Tropical Land Use Systems

Despite an increasing amount of data on the effects of tropical land use on continental forest fauna and flora, it is debatable whether the choice of the indicator variables allows for a proper evaluation of the role of modified habitats in mitigating the global biodiversity crisis. While many single-taxon studies have highlighted that species with narrow geographic ranges especially suffer from habitat modification, there is no multi-taxa study available which consistently focuses on geographic range composition of the studied indicator groups. We compiled geographic range data for 180 bird, 119 butterfly, 204 tree and 219 understorey plant species sampled along a gradient of habitat modification ranging from near-primary forest through young secondary forest and agroforestry systems to annual crops in the southwestern lowlands of Cameroon. We found very similar patterns of declining species richness with increasing habitat modification between taxon-specific groups of similar geographic range categories. At the 8 km2 spatial level, estimated richness of endemic species declined in all groups by 21% (birds) to 91% (trees) from forests to annual crops, while estimated richness of widespread species increased by +101% (trees) to +275% (understorey plants), or remained stable (- 2%, butterflies). Even traditional agroforestry systems lost estimated endemic species richness by - 18% (birds) to - 90% (understorey plants). Endemic species richness of one taxon explained between 37% and 57% of others (positive correlations) and taxon-specific richness in widespread species explained up to 76% of variation in richness of endemic species (negative correlations). The key implication of this study is that the range size aspect is fundamental in assessments of conservation value via species inventory data from modified habitats. The study also suggests that even ecologically friendly agricultural matrices may be of much lower value for tropical conservation than indicated by mere biodiversity value

Land-use effects on local biodiversity in tropical forests vary between continents

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European agricultural landscapes, common agricultural policy and ecosystem services: a review

Since the 1950s, intensification and scale enlargement of agriculture have changed agricultural landscapes across Europe. The intensification and scale enlargement of farming was initially driven by the large-scale application of synthetic fertilizers, mechanization and subsidies of the European Common Agricultural Policy (CAP). Then, after the 1990s, a further intensification and scale enlargement, and land abandonment in less favored areas was caused by globalization of commodity markets and CAP reforms. The landscape changes during the past six decades have changed the flows and values of ecosystem services. Here, we have reviewed the literature on agricultural policies and management, landscape structure and composition, and the contribution of ecosystem services to regional competitiveness. The objective was to define an analytical framework to determine and assess ecosystem services at the landscape scale. In contrast to natural ecosystems, ecosystem service flows and values in agricultural landscapes are often a result of interactions between agricultural management and ecological structures. We describe how land management by farmers and other land managers relates to landscape structure and composition. We also examine the influence of commodity markets and policies on the behavior of land managers. Additionally, we studied the influence of consumer demand on flows and values of the ecosystem services that originate from the agricultural landscape

Averting biodiversity collapse in tropical forest protected areas

The rapid disruption of tropical forests probably imperils global biodiversity more than any other contemporary phenomenon¹⁻³. With deforestation advancing quickly, protected areas are increasingly becoming final refuges for threatened species and natural ecosystem processes. However, many protected areas in the tropics are themselves vulnerable to human encroachment and other environmental stresses⁴⁻⁹. As pressures mount, it is vital to know whether existing reserves can sustain their biodiversity. A critical constraint in addressing this question has been that data describing a broad array of biodiversity groups have been unavailable for a sufficiently large and representative sample of reserves. Here we present a uniquely comprehensive data set on changes over the past 20 to 30 years in 31 functional groups of species and 21 potential drivers of environmental change, for 60 protected areas stratified across the world’s major tropical regions. Our analysis reveals great variation in reserve ‘health’: about half of all reserves have been effective or performed passably, but the rest are experiencing an erosion of biodiversity that is often alarmingly widespread taxonomically and functionally. Habitat disruption, hunting and forest-product exploitation were the strongest predictors of declining reserve health. Crucially, environmental changes immediately outside reserves seemed nearly as important as those inside in determining their ecological fate, with changes inside reserves strongly mirroring those occurring around them. These findings suggest that tropical protected areas are often intimately linked ecologically to their surrounding habitats, and that a failure to stem broad-scale loss and degradation of such habitats could sharply increase the likelihood of serious biodiversity declines.Keywords: Ecology, Environmental scienc

Elevational patterns of species richness and density of rattan palms (Arecaceae: Calamoideae) in Central Sulawesi, Indonesia

We studied species richness and density of rattan palms in 50 plots of 10 × 100 m2 each between 250 m and 2420 m in eight sites in Lore Lindu National Park (LLNP), Central Sulawesi. Rattans were observed in all sample sites, representing three genera and 34 species. The elevational patterns for species richness and density were humped-shaped with maxima around 1000 m. Polynomial models of second order explained 59 and 32% of species richness and density with the factor elevation, respectively. A majority of rattan species (65%) overlapped between 1000 and 1100 m elevation, while a pronounced change in the rattan flora occurred above 1100 m. Commercially important rattan species (Calamus zollingeri, C. ornatus var. celebicus, Daemonorops macroptera) were not observed above 1250 m. The change of species assemblage was significantly related to elevation (56%), followed by geographical distance (47%) and precipitation (40%). Less than 10% of LLNP is lowland forests, much of which is threatened by agricultural intensification. In contrast, montane forests are well represented in the park and high elevation forests are not subject to agricultural conversion or intensive harvesting of rattan and other forest products