Endemic species and ecosystem sensitivity to climate change in Namibia

Authors

  • WILFRIED THUILLER,

    1. Climate Change Research Group, Kirstenbosch Research Centre, South African National Biodiversity Institute, P/Bag x7, Claremont 7735, Cape Town, South Africa,
    2. Laboratoire d'Ecologie Alpine, CNRS, Université Joseph Fourier, BP 53, 38041 Grenoble Cedex 9, France,
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  • GUY F. MIDGLEY,

    1. Climate Change Research Group, Kirstenbosch Research Centre, South African National Biodiversity Institute, P/Bag x7, Claremont 7735, Cape Town, South Africa,
    2. Center for Applied Biodiversity Science, Conservation International, 1919 M St Suite 600, Washington, DC, USA,
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  • GREG O. HUGHES,

    1. Climate Change Research Group, Kirstenbosch Research Centre, South African National Biodiversity Institute, P/Bag x7, Claremont 7735, Cape Town, South Africa,
    2. Environment Systems, ADAS, Woodthorne, Wergs Road, Wolverhampton, WV6 8TQ, UK,
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  • BASTIAN BOMHARD,

    1. Climate Change Research Group, Kirstenbosch Research Centre, South African National Biodiversity Institute, P/Bag x7, Claremont 7735, Cape Town, South Africa,
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  • GILL DREW,

    1. Climate Change Research Group, Kirstenbosch Research Centre, South African National Biodiversity Institute, P/Bag x7, Claremont 7735, Cape Town, South Africa,
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  • MICHAEL C. RUTHERFORD,

    1. Climate Change Research Group, Kirstenbosch Research Centre, South African National Biodiversity Institute, P/Bag x7, Claremont 7735, Cape Town, South Africa,
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  • F. IAN WOODWARD

    1. Department of Animal & Plant Sciences, University of Sheffield, Sheffield S10 2TN, UK
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Wilfried Thuiller, Laboratoire d'Ecologie Alpine, UMR-CNRS 5553, Université Joseph Fourier, BP 53, 38041 Grenoble Cedex 9, France, e-mail: Wilfried.thuiller@ujf-grenoble.fr

Abstract

We present a first assessment of the potential impacts of anthropogenic climate change on the endemic flora of Namibia, and on its vegetation structure and function, for a projected climate in ∼2050 and ∼2080. We used both niche-based models (NBM) to evaluate the sensitivity of 159 endemic species to climate change (of an original 1020 plant species modeled) and a dynamic global vegetation model (DGVM) to assess the impacts of climate change on vegetation structure and ecosystem functioning.

Endemic species modeled by NBM are moderately sensitive to projected climate change. Fewer than 5% are predicted to experience complete range loss by 2080, although more than 47% of the species are expected to be vulnerable (range reduction >30%) by 2080 if they are assumed unable to migrate. Disaggregation of results by life-form showed distinct patterns. Endemic species of perennial herb, geophyte and tree life-formsare predicted to be negatively impacted in Namibia, whereas annual herb and succulent endemic species remain relatively stable by 2050 and 2080. Endemic annual herb species are even predicted to extend their range north-eastward into the tree and shrub savanna with migration, and tolerance of novel substrates. The current protected area network is predicted to meet its mandate by protecting most of the current endemicity in Namibia into the future. Vegetation simulated by DGVM is projected to experience a reduction in cover, net primary productivity and leaf area index throughout much of the country by 2050, with important implications for the faunal component of Namibia's ecosystems, and the agricultural sector. The plant functional type (PFT) composition of the major biomes may be substantially affected by climate change and rising atmospheric CO2– currently widespread deciduous broad leaved trees and C4 PFTs decline, with the C4 PFT particularly negatively affected by rising atmospheric CO2 impacts by ∼2080 and deciduous broad leaved trees more likely directly impacted by drying and warming. The C3 PFT may increase in prominence in the northwestern quadrant of the country by ∼2080 as CO2 concentrations increase. These results suggest that substantial changes in species diversity, vegetation structure and ecosystem functioning can be expected in Namibia with anticipated climate change, although endemic plant richness may persist in the topographically diverse central escarpment region.

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