In the final blog in our mini-series Malcolm Ausden, a Principal Ecologist for RSPB, looks at how we create and manage new habitat for wildlife under a changing climate. This topic is one of the many issues covered in the RSPB's new report on the impacts of climate change on wildlife.
Changes in climate add an additional layer of complexity to how we design and manage our nature reserves. How do we decide what’s best to do now, when the climate and species’ distributions are likely to be quite different in the future? And how is the climate likely to change anyway?
Despite the uncertainties over how the climate might change, there is sufficient consensus on its expected direction of travel, to help inform what we need to do now.
When deciding actions to try and lessen the overall impacts of climate change on wildlife, it is useful to distinguish between two types of timescales. First, there are measures which we can adapt on short timescales as weather conditions change. For example, changes in climate will affect plant growth, and thereby the number of cattle that we need to graze a wet grassland to provide suitable sward conditions for breeding waders. But we don’t have to plan cattle numbers several decades in advance. Instead, we can adjust our grazing levels on a short timescale in response to growth conditions during that particular year. We just need to be adaptable, and to make informed decisions based on continually monitoring and reviewing of our actions and their impacts.
In contrast, when we are re-creating good wildlife habitat, we want to design this habitat so it continues to provide suitable conditions under a wide range of future climates. This requires taking into account how the climate, and species’ distributions, are expected to change. There are two main situations where we are doing this. The first is in the design of new coastal wetlands, to help offset expected future losses of these due to rising sea levels and increased coastal erosion (as well as to help offset historical losses through land claim). The second is in the hydrological design of our freshwater wetlands, in which we take account of expected future changes in water availability.
We are designing out new coastal wetlands so that they should continue to provide valuable habitat for wildlife under a wide range of future sea levels. A good example of this is the innovative design of the RSPB’s Wallasea Island Wild Coast Project in Essex. Innovative features at Wallasea include the creation of ‘sea level rise adaptation zones’ - gently sloping areas of land designed to maintain rare transitions between high salt marsh and non-tidal grassland under a range of future sea levels. There is an article describing the design and construction of Wallasea in the August edition of British Wildlife.
A good example of a freshwater wetland designed to help cope with expected future changes in water availability is Frampton Marsh RSPB reserve in Lincolnshire. Here, as in the rest of southern and eastern England, changes in climate are expected to reduce water availability in late spring and summer, while periods of heavy rain and drought are also expected to become more common. At Frampton, we collect water in winter (when there is plenty of it) and store it in two reservoirs, so we can use this to top up water levels on the rest of the reserve in late spring and summer. We have also designed the wetland so that different sections of it can be periodically dried out and re-flooded. This not only provides valuable, newly flooded habitat for birds, but also means that in dry years, we have the option of only keeping some areas wet, while in wetter years we keep a larger proportion of the site wet.
We have also been liaising with colleagues on the Continent to increase our understanding of the requirements of birds that might colonise (or are just about colonising) the UK, due to changes in climate and recovery from past declines. Examples of these include Spoonbill and Black-winged Stilt. We have been building the requirements of these and other potential colonists into the design of our wetlands for the future.
Matt Williams, Assistant Warden, RSPB Snape.