CLIMATE CHANGE IMPACTS ON WILD COAST’SBIODIVERSITY

DEREK BERLINER

Outline

• Brief overview of some of the predicted impacts of global climate change on the biodiversity of the Wild Coast

• Consider the major terrestrial biomes of forest, grassland and savanna

Wild Coast : current provincial protected area network is unable to ensure persistence of Wild Coasts unique biodiversity, particularly under scenarios of future population growth and climate change

WCP works within the broad priority areas (see map below) to establish a network of community and expanded provincial PA that works towards biodiversity persistence as well as improved livelihoods.

Key to mapLevel 1 areas : top priorities and/ or where communities have indicated willingness to establish reserves. Level 2 are additional priority areas, where communities still need to be engaged.

Areas where the Wild Coast Project have been active

Human Populations: Natural resources and home farms are an important poverty safety net. Climate change is likely to place increase pressure and uncertainty on this dependency

Summary of expected impacts of climate change in Wild Coast

• Range contractions and range shifts of many species (particularly up altitudinal gradients and from west to east)

• Grasslands most effected- by invasion of savanna tree species and increased bush encroachment, resulting in loss of rangelands .

• Spread of invasive alien plants increased by elevated C02

(evidence suggest that creepers and lianas are particularly favoured)

• Forests may expand in some places (due to elevated C02 favoring trees over grasses), but with expected increased in fires and human population pressure, will mostly shrink .

• Many smaller mangrove forests will disappear due to estuarine mouth closure and flooding (increased catchment water use and less reliable rainfall)

River systems and gorges will form important ecological corridors

Much of the Wild Coast is a dynamic balance between the mosaic of grasslands , forest and woodlands. In the past this relationship was largely mediated by fires and rainfall…

Within the last 20 years or so expanding human populations have increase the rate of forest loss through slash and burn agriculture . This, along with the spread of invasive alien plants that rapidly colonize cleared lands are having a major impact on the vegetation of the wild coast. These areas provide a foot-hold for invasive plants to spread into surrounding grasslands .

Picture shows cleared forest for lands , infested with alien plants (light green in center),typical of many areas on the Wild Coast

…but increased human pressure via slash and burn deforestation and alien invasive plants have changed this dynamic.

Invasive alien plants already a big problem on Wild Coast will be stimulated by increased C02 levels

Bulungula mangroves , complete loss due to mouth closure

Kobonqaba estuary 80 % loss in mangroves due to mouth closure in (2010)

The fact that this is the most southern mangrove population in the world could suggest a link with climate change ?

Forest or woodland expansion?

Within the last 20 years or so expanding human populations have increase the rate of forest loss through slash and burn agriculture . This, along with the spread of invasive alien plants that rapidly colonize cleared lands are having a major impact on the vegetation of the wild coast. These areas provide a foot hold for invasive plants to spread into surrounding grasslands .

Picture shows cleared forest for lands , infested with alien plants (light green in center

Slash and burn deforestation and alien invasive plants

AIP used as hedging around homesteads

Chromoleana has become a big problem and spreading fast north of Port St Johns, particularly in Nstubane forest. Increased Co2 is stimulating this spread.

Climate Change and forest degradation from Chromoleana and creeper spread (this will be how much

forest will look like under future climate change)

Driving forces of forest loss on the Wild Coast . Climate change can be expected to speed up these changes (from Berliner, in prep)

Conclusions

• Climate change will act synergistically with all major threats to biodiversity on the wild coast, these include :

• invasive alien plants,

• rangeland degradation (bush encroachment, soil erosion)

• non- sustainable agriculture (forest and grassland loss)

• and breakdown in resource use controls.