Climate change is not a distant threat; its effects are already felt globally, including in the United Kingdom. Among the many living organisms, birds are particularly vulnerable to the consequences of a warming world: The changing climate is altering their habitats, disrupting their life cycles, and challenging their survival. However, there are proactive measures we can take to mitigate these impacts and safeguard the rich avian biodiversity of the UK.
A recently published study by the British Trust for Ornithology has revealed alarming predictions for the seabird populations in the UK. If global warming remains unchecked, these populations could experience a drastic decline of up to 90% by 2050 due to the changing marine environment caused by rising temperatures.
The escalating water temperatures directly impact the abundance of sand eels, which serve as the primary prey species for puffins. Consequently, this adversely affects the breeding productivity of puffins themselves. The BTO report also highlights the negative consequences for other seabirds, such as the kittiwake. Disturbingly, out of the 20 breeding seabird species in the UK, 11 are considered highly vulnerable to the potential effects of climate change.
The significance of the UK's seabird populations extends beyond national borders, as they hold international importance. Therefore, urgent action is required to address global warming and mitigate its impact on the marine environment. Safeguarding these diverse seabird populations in the UK is crucial for their conservation and preservation.
Research indicates that approximately 7% of bird species face a heightened risk of extinction due to global climate change. However, it is essential to note that the risk of death consistently intensifies with the increasing magnitude of climate change.
As our planet undergoes unprecedented changes in climate, the intricate web of ecological interactions is being reshaped, with bird species at the forefront of this transformative phenomenon.
Rising temperatures are causing bird species to adjust their ranges. Some species are expanding northwards or to higher altitudes, while others may experience range contractions. This reshuffling poses challenges for both migrating and resident birds, potentially leading to changes in community dynamics and competition for resources.
Climate change is causing a consistent movement of species towards the poles, with an average displacement of 17 km per decade (Chen et al., 2011). In the case of birds, this shift is even more pronounced, exceeding 11 km per decade (Pearce-Higgins & Green, 2014). In regions with medium and high latitudes, warming is primarily responsible for driving these changes (Chen et al., 2011). However, in tropical areas, species shifts may occur in multiple directions due to the complex responses to alterations in rainfall patterns (VanDerWal et al., 2013).
Many species with southern distributions have expanded their ranges in the UK due to recent warming (Massimino et al., 2015). Ausden et al. (2015) identified eleven waterbird species, two lowland terrestrial species, and two woodland species as likely to colonise the UK. Among them, Night Heron, Little Bittern, Cattle Egret, and Great White Egret have already established breeding populations (RBBP). Additionally, combined modelling of UK and French Breeding Bird Survey data identified eight (8) species that currently do not breed in the UK but are projected to find suitable breeding conditions due to changes in climatic conditions. These species include Black Kite, Short-toed Treecreeper, and Bonelli's Warbler (Massimino et al., 2017).
The timing of crucial life events, such as breeding and migration, is closely tied to seasonal changes. However, climate change disrupts these synchronisations. For example, the earlier arrival of spring due to warmer temperatures may cause some bird species to arrive after peak food availability, leading to reduced reproductive success.
Both European and North American bird populations are experiencing the effects of climate change, as documented by Stephens et al. (2016) and Mason et al. (2019). A global perspective reveals that bird populations have faced significant declines in regions where warming has occurred most rapidly (Spooner et al., 2018). The response of bird populations to temperature variations is particularly pronounced in intermediate and high latitudes, while in tropical areas, precipitation changes play a more significant role (Pearce-Higgins et al., 2015). The primary driving force behind these changes appears to be alterations in species interactions, such as reductions in prey availability, rather than direct responses to rising temperatures (Cahill et al., 2013; Ockendon et al., 2014).
Changing climate conditions influence vegetation patterns, leading to shifts in bird habitats: Wetland birds may face threats from rising sea levels and coastal erosion, while upland birds might experience habitat fragmentation due to changes in vegetation cover. Protecting and restoring habitats become vital to ensuring suitable environments for bird populations.
Due to their extensive journeys across different regions, migratory birds are particularly vulnerable to the impacts of climate change. Climate change contributes to the widespread decline of migratory bird populations globally (Bairlein, 2016). However, the effects of climate change on migratory birds can vary between different stages of their mobile journey, including breeding grounds, stopover locations, and wintering destinations, leading to disruptions in their interdependencies. This complexity in the response of migratory bird populations to climate change arises from differential reactions between breeding and wintering grounds, which differ from those observed in non-migratory species (Pearce-Higgins et al., 2015). As a result of milder winters, significant changes have been observed in the UK's waterbird populations, which play a crucial role in international ecosystems. These populations increasingly choose to winter further north and east in Europe (Maclean et al., 2008). Furthermore, impacts experienced during one stage of a species' global cycle can carry over and affect processes at another location (Finch et al., 2014; Ockendon et al., 2013).
The most compelling evidence regarding the negative impacts of climate change on UK breeding birds can be found in the cases of seabirds and upland birds, which have experienced declines. On the other hand, climate change contributes to population increases and range expansion among breeding waterbirds, including species colonising from continental Europe. An indicator of overall population change, the UK all-species Wild Bird Index, reflecting 130 species, has shown a significant 10% decline since 1970 (Defra, 2020). This decline primarily affects the most common bird species, resulting in considerable bird abundance and biomass loss. Similar patterns of decline can also be observed across Europe (Inger et al., 2015). After agricultural intensification, climate change is considered the second most influential factor in driving breeding population changes since the 1970s, particularly for farmland birds (Eglington & Pearce-Higgins, 2012; Burns et al., 2016). When examining species-specific data, both the Bird Atlas 2007–11 and the annual BTO/JNCC/RSPB Breeding Bird Survey (BBS) and Waterways Breeding Bird Survey (WBBS, Harris et al., 2020) indicate that a similar number of breeding species have experienced increases or declines in their range extent or abundance.
Since the 1990s, one-third of the UK's breeding seabird species have experienced population declines of at least 20-30%. These declines have been accompanied by increasing rates of large-scale breeding failures observed in seabird colonies across the country (Mitchell et al., 2018a, 2018b). As stated, climate change, along with invasive alien species and by-catch in fisheries, has been identified as one of the critical threats to UK seabirds and a significant driver of recent population declines (Dias et al., 2019; Mitchell et al., 2020). Seabirds are vulnerable to various negative impacts associated with climate change (Johnston et al., 2021). Rising sea temperatures disrupt marine food webs, affecting plankton communities and the abundance, size, and availability of fish species that serve as prey for seabirds.
Furthermore, in addition to disruptions in their food chains, seabirds face direct negative impacts from high breeding temperatures (Oswald et al., 2008), mortality due to storms (Burthe et al., 2012), and reduced breeding success in low-lying colonies exposed to flooding risks (Johnston et al., 2021). Under a significant climate change scenario, projections indicate declines of over 50% in the number of internationally important breeding seabirds around the UK by 2080, with 40% of species expected to be Redlisted solely due to climate change. Additionally, 11 out of 19 seabird species are considered highly vulnerable to climate change, with four others classified as moderately weak around Britain and Ireland (Johnston et al., 2013; Davies et al., 2021).
Understanding the potential future impacts of climate change on UK bird populations is crucial. Equally important is identifying any possible effects that may arise from the mitigation measures implemented to address climate change, such as expanding renewable energy generation or undertaking large-scale tree planting to support net-zero targets. It is essential to assess the possible impacts of these measures on bird populations and ensure that they are implemented to minimise any negative consequences for bird species. This comprehensive approach allows us to address climate change while safeguarding the well-being of UK bird populations.
Tree planting is often advocated as a climate change mitigation strategy, but it should be done carefully to avoid unintended negative consequences. While tree planting can provide significant conservation benefits (Calladine et al., 2019), planting trees in inappropriate locations can pose risks to naturally open ecosystems and the species that depend on them (Graham et al., 2017). There are ambitious targets for annual tree planting in the UK, including 5,000 hectares per year in Wales, 7,000 hectares in England, 12,000 hectares in Scotland, and a 9,000 hectares target by 2030 in Northern Ireland. If not properly planned, these initiatives could harm open country birds of conservation concern. However, with careful planning, tree planting efforts can make a positive and vital contribution to the conservation of woodland biodiversity, particularly for bird species that have experienced long-term declines (Defra, 2020).
Past large-scale tree-planting endeavours during the 20th century focused on marginal upland habitats, home to several bird species of conservation concern that are vulnerable to the adverse effects of afforestation (Bunce et al., 2010). Of the 17 upland bird species studied for their associations with woodland habitat, 11 exhibit some avoidance or exclusion from mature woodlands (Pearce-Higgins et al., 2009). Afforestation is recognised as a significant threat to declining wader populations along the East Atlantic Flyway, which includes the UK (Pearce-Higgins et al., 2017). The maturation of large commercial plantations has contributed to a 50% decline in breeding Curlew populations in the UK since 1994 (Franks et al., 2017) and a 70% decline in Black Grouse populations in Perthshire from 1990 to 2002 (Pearce-Higgins et al., 2007). Both species are listed as Birds of Conservation Concern on the UK's Red List.
While certain naturally forested landscapes incorporating open and semi-open habitats can support these species, many available country species experience adverse effects from commercial tree planting extending at least 1 km from the woodland edge (Wilson et al., 2014). Collecting large-scale data by skilled volunteers, such as through initiatives like the Bird Atlas 2007–11, enables the identification of hotspots where vulnerable open-country species are concentrated.
Regarding expanding renewable energy generation, the UK has set ambitious plans to achieve 40 GW of offshore wind capacity by 2030. However, these plans must be carefully balanced with the need to protect internationally significant seabird populations, which may be directly affected by collision mortality or indirectly impacted through displacement and barrier effects. While some seabirds, like auks and shearwaters, typically fly close to the sea surface and face a low risk of collision, other species, such as Gannets and gulls, fly at higher altitudes and are at a greater risk of crash (Johnston et al., 2014; Ross-Smith et al., 2016).
It is essential to recall that migratory species may face similar threats from wind farms in other locations throughout their annual cycles. The use of remote tracking technologies has allowed for the tracking of individuals from migratory populations of Lesser Black-backed Gulls, revealing their potential vulnerability to both onshore wind farms in Iberia and offshore wind farms in the UK (Thaxter et al., 2019).
Moreover, 140 artists and writers have come together to raise funds for the UK's most vulnerable birds. The initiative known as Red Sixty-Seven was created in response to the urgent need to raise awareness and support for the most vulnerable bird species. Its purpose is to highlight and address the declines of the 67 species listed on the Birds of Conservation Concern Red List. In late 2021, the Red List underwent an update, which resulted in the inclusion of several familiar species, such as Greenfinch, Swift, and House Martin. The addition of these species surprised many, as they were not previously recognised as being at high risk. The updated Red List serves as a reminder of the ongoing challenges faced by our bird populations and the importance of taking action to protect and conserve these species.
Practical Steps for Individual and Collective Environmental Stewardship
Individual actions can make a difference: Reduce your carbon footprint by conserving energy, adopting renewable energy sources, and opting for eco-friendly transportation options. The fewer greenhouse gases we emit, the more we can mitigate climate change.
Support conservation organisations and initiatives to protect and restore critical bird habitats, such as wetlands, forests, and coastal areas. Participate in local habitat restoration projects and engage in responsible land management practices prioritising bird-friendly environments.
Raise your voice and advocate for policies that address climate change and protect bird habitats. Engage with policymakers, support organisations focused on environmental issues, and participate in public consultations related to conservation and climate action.
Create bird-friendly environments in your garden or community. Plant native vegetation that provides food and shelter for birds, avoid using pesticides, and provide access to clean water sources. Participate in citizen science projects and report bird sightings to contribute to research and monitoring efforts.
Share knowledge about the impacts of climate change on birds and the importance of their conservation. Educate others about ways they can contribute to bird protection and promote sustainable practices. Raising awareness can inspire collective action towards a more resilient future.
Conclusion
Conclusively, the pervasive impacts of climate change on avian populations in the United Kingdom necessitate immediate and concerted efforts to mitigate the threats posed to their well-being. The evidence presented underscores the urgency of the situation, with seabird populations facing alarming declines and diverse bird species adapting to shifting ranges and habitats in response to rising temperatures.
It is imperative to acknowledge the importance of international collaboration in addressing the challenges posed by climate change on the UK's avian biodiversity. With their transboundary significance, Seabird populations call for urgent global action to curb rising temperatures and safeguard the marine environments they depend on.
As we navigate these challenges, practical steps for individual and collective environmental stewardship emerge as vital pathways for action. Reducing individual carbon footprints, actively supporting conservation organisations, advocating for robust policies, creating bird-friendly environments, and fostering awareness within communities are tangible measures that can contribute to the resilience and conservation of avian species.
In conclusion, fostering a harmonious coexistence between human activities and avian biodiversity demands a paradigm shift in our collective approach. By embracing sustainable practices, advocating for policies that address climate change, and fostering a deeper understanding of the intricacies of avian ecology, we can forge a path towards a more resilient future for the diverse bird populations that enrich the landscapes of the United Kingdom.