Impacts of past habitat loss and future climate change on the range dynamics of South African Proteaceae
Diversity and Distributions
Plant Ecology and Nature Conservation, Institute of Biochemistry and Biology, University of Potsdam, Maulbeerallee 2, Potsdam, 14469, Germany; University of Göttingen, Büsgenweg 2, Göttingen, 37077, Germany; Laboratoire D'Ecologie Alpine, UMR-CNRS 5553, Université Joseph Fourier, BP53, Grenoble cedex 9, 38041, France; Institute for Physical Geography, Goethe University Frankfurt/Main, Altenhöferallee 1, Frankfurt/Main, 60438, Germany; South African National Biodiversity Institute, Cape Town, 7735, South Africa; School of Agricultural, Earth, and Environment Sciences, University of Kwazulu-Natal, Pietermaritzburg Campus. Pvt Bag X101, Scottsville, 3209, South Africa; Biodiversity Planning Unit, South African National Biodiversity Institute, Private Bag x101, Pretoria, South Africa; Institut des Sciences de l'Evolution, UMR 5554, Université Montpellier 2, Montpellier cedex 5, France
Aim: To assess how habitat loss and climate change interact in affecting the range dynamics of species and to quantify how predicted range dynamics depend on demographic properties of species and the severity of environmental change. Location: South African Cape Floristic Region. Methods: We use data-driven demographic models to assess the impacts of past habitat loss and future climate change on range size, range filing and abundances of eight species of woody plants (Proteaceae). The species-specific models employ a hybrid approach that simulates population dynamics and long-distance dispersal on top of expected spatio-temporal dynamics of suitable habitat. Results: Climate change was mainly predicted to reduce range size and range filling (because of a combination of strong habitat shifts with low migration ability). In contrast, habitat loss mostly decreased mean local abundance. For most species and response measures, the combination of habitat loss and climate change had the most severe effect. Yet, this combined effect was mostly smaller than expected from adding or multiplying effects of the individual environmental drivers. This seems to be because climate change shifts suitable habitats to regions less affected by habitat loss. Interspecific variation in range size responses depended mostly on the severity of environmental change, whereas responses in range filling and local abundance depended mostly on demographic properties of species. While most surviving populations concentrated in areas that remain climatically suitable, refugia for multiple species were overestimated by simply overlying habitat models and ignoring demography. Main conclusions: Demographic models of range dynamics can simultaneously predict the response of range size, abundance and range filling to multiple drivers of environmental change. Demographic knowledge is particularly needed to predict abundance responses and to identify areas that can serve as biodiversity refugia under climate change. These findings highlight the need for data-driven, demographic assessments in conservation biogeography. © 2012 Blackwell Publishing Ltd.
abundance; Cape Floristic Region; climate change; demography; dicotyledon; dispersal; environmental impact assessment; geographical distribution; habitat loss; population dynamics; range size; refugium; South Africa; Proteaceae