Newly published research led by the BTO shows a consistent impact of climate change on biodiversity around the world. A new analysis of the results from over 130 previously published studies of wild species, ranging from alder trees to zebras, has found a consistent impact of climate change on global biodiversity. The research, led by BTO scientists working in collaboration with organisations from the Cambridge Conservation Initiative, showed that populations of many species actually respond positively to warmer temperatures, with cold weather associated with population declines, particularly in temperate countries like the UK. However, this positive effect of temperature was largely negated where there was a significant long-term warming trend, demonstrating that climate change is already affecting species' populations. Rainfall was the most important factor influencing species’ populations in tropical and sub-tropical regions, where wetter weather generally has a positive effect. Here again there was evidence that climate change may be negatively affecting species through the detrimental impacts of drought. This study not only indicates that climate change is affecting many species around the world now, but importantly shows that the ways in which climate change affects species varies with location. In the tropics, changes in rainfall and therefore drought conditions will probably have the greatest impact on species’ populations, communities and ecosystems. This means that conservation management to help species cope with climate change in these areas should focus on managing water levels. However, the processes will be different at higher latitudes, where the impact of warming is likely to be more important. The effect of warming in temperate latitudes helps explain why many bird populations in the UK have increased as temperatures have risen, leading to polewards shifts in the distribution of those species. However, in the tropics, we would expect species’ range shifts to be driven as much by changing rainfall patterns as by temperature, and therefore species’ may not simply shift polewards away from the equator. Given that the impacts of climate change upon biodiversity in the tropics are likely to involve different ecological mechanisms from those impacts at higher latitudes, there is an urgent need to establish robust monitoring and long-term biodiversity studies across tropical regions to track the changes that occur. This research underlines the widespread and complex implications of climate change across the natural world, and identifies areas in which further research and monitoring is needed to address and reverse the negative impacts on biodiversity.

BTO research has used data from the Breeding Bird Survey to show that many of our birds have expanded their geographic range as a short-term response to climate change. BTO research, led by Dario Massimino of the Population Ecology and Modelling Team, has used data from the Breeding Bird Survey to investigate the short-term response of breeding birds in Britain to recent temperature changes. Many models of climate change predict contractions in species range and increased extinction risk. This study looked at the period between 1994 and 2009, during which Britain experienced an average temperature increase of 0.59°C. The analysis of the population density of 80 bird species during these years showed an expansion in the majority of these species’ ranges. The paper’s authors examined the northern and southernmost extent of where these species occur in the UK (the range margins), and found that the northern margin had shifted north by approximately 45 km on average. Over the same period, the southern margin had remained largely static, amounting to a northwards range expansion for the species concerned. This research also explored whether species had shifted to higher altitudes as British temperature rose, but found no consistent response. The results of the study show that bird movements are not keeping pace with temperature changes. With the change in temperature recorded, birds were expected to shift northwards by 108 km or upwards by 63 m. Climate change impacts on biodiversity are largely of concern due to the magnitude of future projected impacts, so the absence of short-term adverse effects found in this study should not be taken to mean that climate change will not cause range contraction in many species. Instead, the study underlines the importance of long-term monitoring to detect, document and properly describe the impact of climate change on biodiversity and ecosystems, so that conservation action can be optimally targeted.

This edition includes the annual breeding season results for 2015 as well as articles on monitoring Starlings and Dippers, finding Wood Warbler and Stonechat nests, undertaking a Wheatear RAS, and ringing on RSPB reserves.