Developing regional and species-level assessments of climate change impacts on biodiversity in the Cape Floristic Region
Introduction
Recently documented biotic responses to possible human-induced climate change (Hughes, 2000, Peterson et al., 2002) raise a crucial question for conservationists: Are projected climate changes likely to be a threat to the conservation of biodiversity? Conservation efforts have generally assumed that climate is a constant feature of the environment, and that species distributions are effectively constant in space and time (Cowling, 1999). Both the former and latter assumptions are unjustifiable, as it is now well understood that the earth's climate has changed significantly and rapidly on time scales of decades to millennia (Broecker, 1999, Zachos et al., 2001); that species have shifted their ranges as climate has changed (Hewitt, 2000, Huntley and Birks, 1983, Parmesan, 1996, Parmesan et al., 1999); and that these range shifts are often individualistic responses to climate change (Graham and Grimm, 1990, Warren et al., 2001) as opposed to wholesale migrations of ecosystems or biomes. Several authors have begun to explore how conservation plans can begin to assess this threat and incorporate these insights into strategies that will be robust to climate change (e.g. Halpin, 1997, Hannah et al., 2002), and some planning to accommodate climate change impacts has been developed for the CFR (Cowling and Pressey, 2001, Cowling et al., in press, Rouget et al., in press) and for the winter rainfall Succulent Karoo Biome of South Africa (Cowling et al., 1999a). Nonetheless, explicit adaptations to conservation planning in the face of climate change are in their infancy.
The CFR boasts an exceptionally rich flora with high levels of endemism (Cowling et al., 1989), that may result, in part, from a unique climate and climate history (Cowling et al., 1998, Midgley et al., 2001). The mediterranean-type climate of the CFR may now be changing, characterised by increasing temperatures and reduced rainfall, especially in winter months (Tyson et al., 2002, Wand et al., submitted for publication). Conservation planning for the region has just begun to account for these significant changes and the impact they may have in concert with other threats (Cowling and Pressey, 2001, Cowling et al., in press, Rouget et al., in press).
If species range shifts are the likely dominant species response to future climate change, then spatially explicit planning will be fundamental to estimating the rate and direction of species movements required to ensure retention of sufficient range for their persistence. Modelling can help inform efforts to place land under effective conservation management, either in formally protected areas or in unprotected areas suitable as habitat. These tools must be relevant at regional and even sub-regional scales—the scales at which most practical conservation decisions, such as land acquisitions, are made.
In this paper, we develop a biome- and a species-based approach to assessing the regional impacts of climate change on the future distribution of a major floristic group (Proteaceae). We address a number of questions:
- 1.
What biome-level patterns may be expected under future climate change, and what are the comparative potential range shifts in representatives of a dominant taxon, the Proteaceae, in areas of potential biome contraction?
- 2.
How much has land transformation constrained the potential migration of species in response to climate change?
- 3.
What proportion of species are under severe threat of extinction under the projected climate change scenarios?
- 4.
What are the implications of these patterns for conservation planning?
Section snippets
Study area and selected species
We modelled the Fynbos Biome (sensu Rutherford and Westfall, 1994) and selected endemic members of the family Proteaceae within the CFR. The Fynbos Biome is the dominant biome within the Cape Floristic Region. We focused attention on the western parts of the CFR, having established large potential impacts of climate change in this region (Midgley et al., 2003). The study area includes much of the western Cape (between 33–35° S and 18–22° E), a region that has a Mediterranean-type climate with
Regional-level assessment
Biome-level modelling shows that the Fynbos Biome stands to lose significant areas near its northerly (equatorward) limits, especially in the coastal forelands and inland plains along the west coast (see Fig. 1) in response to projected climate change. The biome envelope suggests future contraction southwards onto the mountains of the Cape Fold Belt. Plains and slopes at lower altitudes along the west coast and northern borders of this mountain belt do not retain suitable bioclimates for
Acknowledgments
We acknowledge with thanks comprehensive funding from the Centre for Applied Biodiversity Science, Conservation International, Washington, DC, and helpful and constructive comments from Richard Cowling and Bob Pressey on an earlier draft of this paper.
References (48)
- et al.
Effects of global climate change on the patterns of terrestrial biological communities
Trends in Ecology and Evolution
(1990) Biological consequences of global warmingis the signal already apparent?
Trends in Ecology and Evolution
(2000)- et al.
Assessing the effects of forecasted climate change on the diversity and distribution of European higher plants for 2050
Global Change Biology
(2002) What if the conveyor were to shut down? Reflections on a possible outcome of the great global experiment
GSA Today
(1999)A bioclimatic analysis and prediction system
The Ecology of Fynbos: Nutrients, Fire and Diversity
(1992)Planning for persistence—systematic reserve design in southern Africa's Succulent Karoo desert
Parks
(1999)- et al.
Rapid plant diversificationplanning for an evolutionary future
Proceedings of the National Academy of Sciences
(2001) - et al.
Patterns of plant species diversity in southern Africa
- et al.
Extraordinarily high regional-scale plant diversity in southern African arid landssubcontinental and global comparisons
Diversity and Distributions
(1998)
From representation to persistencerequirement for a sustainable reserve system in the species rich mediterranean-climate deserts of southern Africa
Diversity and Distributions
Fossil wood charcoal assemblages from Elands Bay Cave, South Africaimplications for Late Quaternary vegetation and climates in the winter-rainfall fynbos biome
Journal of Biogeography
Global response of terrestrial ecosystem structure and function to CO2 and climate changeresults from six dynamic global vegetation models
Global Change Biology
South African National Land Cover Database Project. Data Users Manual (Final Report ENV/P/C 98136)
More efficient plantsa consequence of rising atmospheric CO2?
Annual Review of Plant Physiology and Plant Molecular Biology
Global climate change and natural-area protectionmanagement responses and research directions
Ecological Applications
Conservation of biodiversity in a changing climate
Conservation Biology
Generalized Additive Models
The genetic legacy of the quaternary ice ages
Nature
An Atlas of Past and Present Pollen Maps for Europe, 0–13000 B.P
Plant reproductive ecology
Past climate change and the generation and persistence of species richness in a biodiversity hotspot, the Cape Flora of South Africa
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