Dario Massimino

Phenological sensitivity to climate across taxa and trophic levels

Differences in phenological responses to climate change among species can desynchronise ecological interactions and thereby threaten ecosystem function. To assess these threats, we must quantify the relative impact of climate change on species at different trophic levels. Here, we apply a Climate Sensitivity Profile approach to 10,003 terrestrial and aquatic phenological data sets, spatially matched to temperature and precipitation data, to quantify variation in climate sensitivity. The direction, magnitude and timing of climate sensitivity varied markedly among organisms within taxonomic and trophic groups. Despite this variability, we detected systematic variation in the direction and magnitude of phenological climate sensitivity. Secondary consumers showed consistently lower climate sensitivity than other groups. We used mid-century climate change projections to estimate that the timing of phenological events could change more for primary consumers than for species in other trophic levels (6.2 versus 2.5–2.9 days earlier on average), with substantial taxonomic variation (1.1–14.8 days earlier on average).

Should we account for detectability in population trends

Capsule Accounting for changes in detectability over time which could invalidate population trends for common and widespread breeding birds in the UK, resulted in little change in trends for the majority of species considered. Aims To examine whether detectability has a significant influence on population trends for common and widespread breeding birds in the UK. Methods Using data collected over 16 years of the UK Breeding Bird Survey (1994–2009) and focusing on a random sample of 20 common and widespread bird species, we examine the extent to which controlling for temporal change in detectability would influence national population trends. Results Population trends were significantly different for only 2 of the 20 species, Common Blackbird and Winter Wren. This difference corresponds to an apparent fall off in detectability of these species between 2005 and 2009. For the remaining species, controlling for detectability resulted in no significant difference in population trends. Conclusions The importance of detectability should be examined as part of any long-term monitoring programme. However, currently we do not find sufficient support for routinely incorporating detectability into population trends for widespread and abundant breeding birds in the UK.

The geographical range of British birds expands during 15 years of warming

Capsule Abundance monitoring data suggest that the short-term response of breeding birds to recent warming in Great Britain has been range expansion, caused by poleward shifts of leading range margins and no significant shifts of trailing range margins. Aims To quantify latitudinal and elevational shifts of breeding bird populations in Great Britain and test for differential shifts in range margins during a period of warming (1994–2009). Methods We modelled the population density of 80 species as a smooth function of latitude, longitude, elevation and year. Reference points on the distribution curve were used to describe latitudinal and elevational shifts. Results Across species, poleward shifts in the leading range margin were greater than in the range-centre. The trailing range margin was largely static, providing evidence for significant range expansion. The magnitude of latitudinal range shift lagged behind the equivalent shift in temperature, suggesting that species may be accumulating a climatic debt. There was no evidence for consistent elevational shifts. Conclusion Contrary to the generally expected long-term consequences of climate change of range contraction, we show that the short-term response to recent warming has been range expansion. This suggests the mechanisms of short-term and long-term consequences of climate change may differ.

Species traits explain variation in detectability of UK birds

Capsule Heterogeneous detectability amongst species may impact multi-species bird surveys and if not accounted for, may bias community level conclusions. Estimates of detectability were produced for 195 UK bird species, and detectability was significantly affected by bird size, diet and habitat specialization. Aims To estimate detectability and understand which species traits may impact detectability. Methods We estimated the detectability of 195 species of birds in the UK using distance sampling methods and examined the average detectability of genetically related groups. We tested the significance of species traits in describing variation in detectability, whilst controlling for phylogenetic relationships. Results Passeriformes had the lowest median detectability of 0.37 and Charadriiformes the highest median detectability of 0.65, of the seven largest orders considered. Species most associated with closed habitats such as woodland and urban areas had the lowest detectability. Smaller species had lower detectability than larger species. Conclusion Heterogeneity in species detectability could lead to biased conclusions, particularly when calculating multi-species indices such as species richness or diversity. Accounting for detectability will be most important in studies that cover a wide range of habitat types or a diverse spread of taxa.

Projected reductions in climatic suitability for vulnerable British birds

Projections of species’ distributions in future climates can aid adaptive conservation strategies. Although presence-absence or presence-only data have been extensively used for this purpose, modelling changes in spatial patterns of abundance provides a more sensitive tool for estimating species’ vulnerabilities to climate impacts. We used abundance data from citizen science bird surveys in the UK and France to predict spatial patterns of future climatic suitability throughout Great Britain for 124 breeding bird species. We project that climatic suitability of Great Britain will increase for 44% of species and decline for 9% of species by 2080. Of the latter group, most are already red-listed for their severe long-term population declines. If our suitability projections translate into population changes, by 2080, conservation listing status will worsen for 10 species and improve for 28 species. Projected changes in climatic suitability translate into net gains of species abundance in northern and western areas and high turnover in community composition throughout Britain, particularly under medium- and high-emission scenarios. In conclusion, community-wide projections of changes in climatic suitability based on abundance indicate that bird assemblages throughout Great Britain will be impacted by climate change and that species already of concern are likely to be impacted hardest. Of the species projected to benefit, the ability of currently red-listed species to respond positively to climate without other interventions is unclear.