Predicting plant diversity patterns in Madagascar : understanding the effects of climate and land cover change in a biodiversity hotspot

Climate and land cover change are driving a major reorganization of terrestrial biotic communities in tropical ecosystems. In an effort to understand how biodiversity patterns in the tropics will respond to individual and combined effects of these two drivers of environmental change, we use species distribution models (SDMs) calibrated for recent climate and land cover variables and projected to future scenarios to predict changes in diversity patterns in Madagascar. We collected occurrence records for 828 plant genera and 2186 plant species. We developed three scenarios, (i.e., climate only, land cover only and combined climate-land cover) based on recent and future climate and land cover variables. We used this modelling framework to investigate how the impacts of changes to climate and land cover influenced biodiversity across ecoregions and elevation bands. There were large-scale climate- and land cover-driven changes in plant biodiversity across Madagascar, including both losses and gains in diversity. The sharpest declines in biodiversity were projected for the eastern escarpment and high elevation ecosystems. Sharp declines in diversity were driven by the combined climate-land cover scenarios; however, there were subtle, region-specific differences in model outputs for each scenario, where certain regions experienced relatively higher species loss under climate or land cover only models. We strongly caution that predicted future gains in plant diversity will depend on the development and maintenance of dispersal pathways that connect current and future suitable habitats. The forecast for Madagascar's plant diversity in the face of future environmental change is worrying: regional diversity will continue to decrease in response to the combined effects of climate and land cover change, with habitats such as ericoid thickets and eastern lowland and sub-humid forests particularly vulnerable into the future

Rethinking spatial costs and benefits of fisheries in marine conservation

Fishing catch is often used as a cost in marine conservation planning to avoid areas of high fishing activity when identifying potential marine reserve locations. However, the theory of marine reserves indicates that reserves are more likely to benefit fisheries in areas of heavy fishing activity that would otherwise be overfished. Whether or not fishing catch is calculated as a cost depends on the balance of conservation and fisheries goals for a reserve, and thus is critical for policymakers to consider when designing marine reserve networks. This research shows the utility of running an inverted cost model of fishery catches during marine reserve spatial prioritization as a first step in a marine planning process oriented towards stabilizing local fisheries. This technique serves as a heuristic tool that may help conservation planners explore regions that would otherwise be overlooked if fisheries data were absent or integrated purely as a cost in the planning process. Drawing on data from Madagascar to illustrate our approach, this research demonstrates that the regions most frequently selected using the inverted cost model not only meet conservation targets, but are also those most accessible to community-based resource managers, the dominant management paradigm in Madagascar as well as in many developing countries