Biodiversity

 

Climate change is one of the most important threats to the stability of ecosystems and the conservation of biodiversity. It is expected that over the coming century the climate of the UK will become milder and wetter in winter, and significantly hotter and drier in the summer months, particularly in the southeast of the UK. The frequency of extreme weather events such as heavy rainfall, storms and flooding is also predicted to increase. There is a great deal of uncertainty over the timing and magnitude, but these changes to our climate will be larger and more rapid than any since the last ice-age, posing real problems for woodland biodiversity.

The character and composition of our woodland is likely to change, with new species assemblages developing, particularly in southern Britain where areas will become increasingly unsuitable for some woodland types such as acid oak birch woodland. In addition the climatic conditions for individual species will also change leading to the possible disappearance of some priority species (e.g. twinflower in native pinewoods) and complex and unpredictable interactions developing amongst different species groups. 

It may be necessary to introduce planting stock of non-native provenance if the intention is to retain a resilient cohort of native trees and shrubs. Some knowledge of individual species responses is informative for adapting site management to climate change, but it is also important to maintain ecosystem resilience at a landscape level. This is best achieved through integrating site management measures with improving landscape connectivity.

Research is currently focused on developing tools to help predict the effects of changing climate and land-use on habitat connectivity at the landscape scale. Connectivity means different things to different species, and the emphasis of the research to date has been on modelling connectivity for species of conservation concern and so-called focal species whose ecological characteristics (habitat requirements and dispersal abilities) are suitability generic that they act as a surrogate for a much wider suite of species. The modelling work has links with the MONARCH programme, and will be developed further as more resources are devoted to climate change research. In time this will provide more specific guidance for forest managers and land use planners on how to counteract the effects of climate change on biodiversity. However, in the meantime managers and planners are advised to:

Maintain the resilience of forest ecosystems by creating larger woodland blocks, planting mixtures of species and improving connectivity between woodlands and between other semi-natural habitats.

• Incorporate climate change predictions when assessing the long-term suitability of native woodland communities (including native trees and shrubs) on a given site.
• Take account of water use and availability when making decisions over species choice, particularly in southeast Britain where water shortages are predicted as a result of climate change.
• Consider increasing the genetic diversity of new native woodlands, through selection of planting stock from non-local provenances to provide resilience to climate change.