Climate Change Group Dr. G. Midgley (leader) Dr. C. Musil Dr. M. Rutherford Dr. W. Thuiller Mr. Les Powrie Mr. B. Kgope Mr. G. Hughes Technical Staff Mr. S. Snyders Mr. D. de Witt Mrs. J. Arnolds

Climate Change and Plant Biodiversity Barney S. Kgope South African National Biodiversity Institute, Kirstenbosch Research Center,

Background §What is climate? - An aggregate of daily weather - whose variables interact to support life on earth. §Climate system includes processes involving - land, ocean and sea and these influence - atmosphere. §Biodiversity - variety of life on Earth - significantly influences climate.

Is the climate changing?

Previous Climate We live on a predominantly cool-adapted planet!

Human Influence - fossil fuels

Where are we now? Uncertainty Detection Prediction Policy Behaviour Technology Adaptation

Climate Change Consequences §Human and animal health - e.g. heat and diseases. §Agriculture - food security (warming and drying). §Sea level rise - melting polar ice caps (potential to submerge coastal cities). §Natural ecosystems - changes in structure and function. §Water supply - decline due to potential decrease in rainfall.

South Africa and Climate Change [PMG note: photograph not included]

5 spatially dominant biomes - SA

How did past climate change affect this region? Climate reconstruction

Time (Kya) +0.05ºC -1.82ºC -3.67ºC

Pollen evidence? Shi et al (1998)

Potential Future ?

Water impacts on physiology

Potential shift with climate change (~2050)

Potential for more species. extinction ? Aloe dichotoma (quiver tree)

Elevated and sub-ambient CO 2 work supporting mechanistic modeling Test ideas about impacts of fire and CO 2 on vegetation structure and function [PMG note: photograph not included]

DGVM predictions for CO 2 sensitivity of African mesic Savanna saplings

Implications and tests §Past contraction of woody elements with LGM low CO 2 (180ppm) – paleoecological record §Bush encroachment since the pre- industrial, and accelerating into the future with significant implications for livelihoods, ecosystem function and carbon sequestration – empirical experiments

Modelled effects of CO 2 level alone on tree success (i.t.o. LAI) using a DGVM Bond W.J., Midgley G.F. & Woodward, F.I. (2003) The importance of low atmospheric CO2 and fire in promoting the spread of grasslands and savannas. Global Change Biology 9: Bond W.J., Midgley G.F. & Woodward, F.I. (2003) What controls South African vegetation – climate or fire? South African Journal of Botany.69:1-13

Experimental tests on 3 Savanna woody species and 1 C 4 grass §Plants exposed to a full range of CO 2 levels viz. 180, 280, 370, 550, 700 and 1000 ppm, in Open Top Chambers §Plants - Acacia karoo, Acacia nilotica, Dichrostachys cinerea and Themeda triandra.

Acacia karroo 550 ppm 180 ppm [PMG note: photographs not included]

From pre-industrial to current CO 2 levels? Trees have increased world-wide in savannas Open savanna, S. Africa 1955 Same place, 1998 (from T. Hoffmann, IPC) [PMG note: photograph not included]

What about potential impacts of the predicted increases in ambient temperatures?

Scale up research - biogeochemical cycles Long Term Ecological Research Sites Scale up leaf-canopy- ecosystem-regional- global Integrative studies Networks – Afri-flux [PMG note: photograph not included]

Recommendations §Support – Assessment of Impacts and Adaptation to Climate Change (AIACC) §Support International efforts to curb/limit greenhouse gas emissions §Key intervention - policies promoting sustainable management of biodiversity on private and communal land. §Expansion of protected areas an important adaptation option being implemented in SA §Increase capacity of research on climate change and sustainable development in South Africa

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