An increasing body of research, including much from BTO, demonstrates the impacts of climate change on bird species across the globe, revealing a suite of responses. The timing of bird breeding and of migration have both become earlier, and there is a consistent poleward shift in the distribution of bird species, the rate of change exceeding 11 km per decade. Climate change is driving large-scale shifts in bird communities across the globe, and we are seeing a consistent simplification of bird communities as they become more similar to each other.
BTO data provide the evidence base for many of these changes, underlining the vital role of our long-term monitoring and research work continue to play in understanding climate change impacts and identifying ways in which we can help bird populations adapt to these.
BTO work on climate change can be divided into three main areas:
- Documenting the impacts of climate change on biodiversity.
- Developing and using approaches for predicting future impacts of climate change to identify the most vulnerable species and habitats.
- Improving the evidence base to inform how conservation needs to adapt to climate change.
Although much of our work has a UK bird focus, we also work internationally and on other taxa.
BTO Climate Change Report
In November 2021, alongside the United Nations Climate conference in Glasgow (CoP26), we published an important report assessing the impact that climate change is having on UK bird populations.
The report provides the most comprehensive synthesis of the likely future impacts of climate change on UK birds to date, whilst also highlighting examples of where large-scale climate mitigation work, such as woodland planting, has the potential to transform landscapes and impact on bird populations.
Documenting the impacts of climate change on biodiversity
BTO's long-term datasets provide the evidence base from which we have been able to identify the impacts of climate change on UK birds, and other taxa that we monitor.
One of the most widespread and well-reported effects of climate change has been changes in the timing (phenology) of biological events. It was BTO research which first reported changes in the timing of mean laying date from 1971 to 1995 in about a third of the 65 UK species studied (Crick et al. 1997); this was subsequently linked to increases in temperature (Crick & Sparks 1999).
As BTO research has revealed, climate change can also alter the arrival and departure patterns of summer and winter visitors, bring about shifts in breeding and wintering range, and affect breeding performance and survival.
Predicting future impacts
Much of the concern about the impacts of climate change on populations results from projections in likely changes in the distribution of species in response to climate change. We have been using our long-term datasets in statistical models to infer likely future changes in distribution. Importantly, we have also been able to look at what this means for population abundance and population trends, two key components that shape conservation listing.
Through our work we have been able to provide the most comprehensive synthesis of the likely future impacts of climate change on UK birds to date. Within the UK, breeding seabirds and upland breeding birds are the two groups most vulnerable to climate change.
Conversely, climate change appears to be contributing to population increases and expansion in breeding waterbirds, including species colonising from continental Europe. Southerly-distributed waterbirds, coastal species and heathland species are those most likely to benefit from climate change.
Tendencies for upland birds and seabirds to decline may be related to their more negative responses to warming temperature, whilst positive impacts of temperature change may contribute to increases in wetland and non-native species.
Read more about future impacts
Informing how conservation needs to adapt to climate change
If climate change is to result in significant shifts in the distribution and abundance of species, then it may require long-term planning by conservation organisations in order to adapt. This may involve increasing the connectivity of habitats in order for species to track changes in their climate, increasing the size of protected areas to increase the resilience of those populations to climate change, or managing sites to reduce negative climate change effects.
There is much that current BTO research is doing to inform this process.