Climate change impacts on wildlife populations in the UK

Climate Change and Nature Blog Series No 2

by James Pearce-Higgins

Last month, Colin Beale showed how changes in the timing of spring is one of the clearest fingerprints of climate change. This month we will consider how this and other processes affect the abundance of species around us.

We might think that the main impacts of climate change will be to make it too hot for species to handle, but actually it is the disruption to the interactions between species in an ecosystem that climate change causes which drive many of the impacts that we see. For example, as many of our breeding birds, like the blue tit, eat insects, any climate-driven change in insect availability, may affect the number of chicks they are able to fledge in any one season. Climate change, amongst other factors, may be contributing to long-term declines in some moth species. This potentially reduces woodland bird food supplies, whilst much-loved species like the garden tiger moth are now a rare sight in southern Britain as a result of warmer, wetter winters. 

Fortunately for resident woodland and garden birds like the blue and great tit, any potentially negative impacts on their insect food have so far been compensated by the positive impact of warmer winters on their populations. In recent years, we haven’t had the same frequency or  severity of very cold winters which has, in the past,  knocked-back many of our resident bird populations by increasing mortality. As a result, many resident birds, particularly small insect-eaters like the goldcrest and wren, have increased in abundance as more survive to breed each year.

If warmer temperatures have increased the abundance of these birds, what is the problem with climate change? Focussing on these common and widespread garden species, only tells part of the story. Compare their positive trends with those of more specialised cold-adapted bird species, such as the dotterel associated with mountain tops. Or what about our northern seabirds, many of which are in decline, at least partly due to climate change? Much-loved seabirds like the kittiwake and puffin are increasingly struggling to breed in some years due to a lack of lesser sand eels in our warming seas. Closer to home, not all is necessarily rosy either; Hot, dry summers reduce the availability of earthworms in the surface of the soil, impacting thrush populations that rely upon them, particularly in south-east England. 

These population impacts are detected only through the dedication of an army of volunteers or ‘citizen scientists’ that support the majority of large-scale and long-term monitoring programmes in the UK. As Spring approaches, whether you are interested in birds or butterflies, plants or pollinators, there are plenty of opportunities to get involved. 

Want to find out more? 

• The Joint Nature Conservation Committee (JNCC) website is a useful reference point for links to different surveys and organisations, many of which may also offer training.
• BTO Garden BirdWatch is an opportunity to help with research into garden wildlife and offers activities all-year round.
• RSPB Big Garden Birdwatch (annual event in January) – Contribute to the world’s largest wildlife survey and discover the wildlife on your doorstep in winter (an annual event, occurring in January). Sign up on the RSPB’s website here for all you need to take part, including your free guide, help with identifying what you see and expert advice on feeding the birds.
• BTO Breeding Bird Survey (BBS) – The BBS monitors the population changes of 117 breeding bird species across the UK thanks to the dedication of almost 3,000 volunteers who survey their randomly selected 1-km square each spring. See here for further information.
• Churches Count on Nature – An exciting initiative open to all denominations, is a nature-recording project which will be piloted by Caring for God’s Acre and the Church of England, in partnership with A Rocha UK. Participating churches will be encouraged to act for wildlife by recording nature in their church yards, spaces and burial grounds or nearby land. Express your interest in taking part here.

In part 3 of our climate and the UK series, Colin Beale will consider how these population impacts scale-up to affect species’ distributions and ecological communities. Read this here.

About the author: Professor James Pearce-Higgins is the Director of Science at the British Trust for Ornithology and a trustee of A Rocha UK.

This blog was written for A Rocha UK’s Wild Christian email, March 2021. Sign up here to receive future Wild Christian emails