Climate change imperils an entire UK ecosystem

Red grouse among heather in the northern England uplands.
Image: Milo Bostock via Flickr

In the upland peat bogs of Britain, global warming is killing insects and jeopardising the rare birds that depend on them. LONDON, 3 August, 2015 – The UK may still be fairly well sheltered from the impacts of climate change, but British scientists now say the increasingly warm trend is threatening an entire eco-system. They have found that several rare upland bird species are at risk, together with other ecosystem functions, because of the effects of climate change on the UK’s blanket bogs −  the peat bogs found mainly in the wetter western and northern uplands of Britain. Following their study of uplands from mid-Wales to northern England, they report in Nature Communications that “climate change could drive substantial declines in abundances of keystone invertebrates and their predators, acting through soil moisture”.

Risk for people

Several bird species − including the dunlin, golden plover and red grouse − depend on these wetlands for nesting and feeding, and there is a risk for people as well, because most drinking water comes from the upland peats. Ecologists at the University of York and colleagues found that climate change threatens the bogs, not only through rising temperatures from increasing peat decomposition but also because of altered rainfall patterns, with summer droughts drastically affecting the bogs’ hydrology. The study showed that an insect called the crane fly − often known as the daddy longlegs − is crucial to determining the impact of climate change on peatland bird species. The birds depend on the protein-rich crane flies as food for chicks, but the scientists found that summer droughts, which are predicted to increase, could cause significant declines in the flies, by 56%-81%, and therefore in the birds that depend on them.

“Everything works together like a jigsaw puzzle − if you change a piece, you will change others around it”

Based on a peatland model developed at the University of York, and on the latest climate change predictions, they say the decline of crane flies could by 2051-80 mean a 50% fall in dunlin numbers, 30% in golden plovers and 15% in red grouse. Another concern is the role of blanket bogs as a carbon store – or source. Globally, peatlands are an important carbon store, representing about 60% of the world’s terrestrial carbon, although they cover less than 3% of the Earth’s surface, and even the UK’s bogs play a significant part. While they are forming, peatlands can absorb carbon, but in degraded peatlands carbon dioxide and other greenhouse gases can be released. So peatlands have a massive potential influence on climate change.

Bug-to-bird link

The peatland model was developed by Dr Andreas Heinemeyer, a Stockholm Environment Institute ecologist based at the University of York. He says: “This is one of the first studies to follow this bug-to-bird link, down the food chain, between climate change and something happening to an entire eco-system, with relevance to people. “There is a very strong relationship between the moisture of the peat and the survival of the larvae of the crane fly during summer. July and August are peak times: if it is too dry, the larvae just desiccate and die, and are then not available for the bird chicks the following year.” And it isn’t only rare birds that were at risk from climate change. Dr Heinemeyer says “We might be in for big change, not just in connection with our birds, but with our drinking water as well. “If you end up being very dry as a blanket bog, you store less water and your water quality seems to deteriorate . . . everything works together like a jigsaw puzzle. If you change a piece, you will change others around it.” – Climate News Network