Continent‐scale global change attribution in European birds ‐ combining annual and decadal time scales

Abstract

Species attributes are commonly used to infer impacts of environmental change on multiyear species trends, e.g. decadal changes in population size. However, by themselves attributes are of limited value in global change attribution since they do not measure the changing environment. A broader foundation for attributing species responses to global change may be achieved by complementing an attributes-based approach by one estimating the relationship between repeated measures of organismal and environmental changes over short time scales. To assess the benefit of this multiscale perspective, we investigate the recent impact of multiple environmental changes on European farmland birds, here focusing on climate change and land use change. We analyze more than 800 time series from 18 countries spanning the past two decades. Analysis of long-term population growth rates documents simultaneous responses that can be attributed to both climate change and land-use change, including long-term increases in populations of hot-dwelling species and declines in long-distance migrants and farmland specialists. In contrast, analysis of annual growth rates yield novel insights into the potential mechanisms driving long-term climate induced change. In particular, we find that birds are affected by winter, spring, and summer conditions depending on the distinct breeding phenology that corresponds to their migratory strategy. Birds in general benefit from higher temperatures or higher primary productivity early on or in the peak of the breeding season with the largest effect sizes observed in cooler parts of species' climatic ranges. Our results document the potential of combining time scales and integrating both species attributes and environmental variables for global change attribution. We suggest such an approach will be of general use when high-resolution time series are available in large-scale biodiversity surveys.

Declining population trends of European mountain birds

“…Thus, in general mountain birds are doing less bad than farmland birds, but clearly worse than forest birds in Europe. The severe declines of farmland birds are mainly driven by intensification of agriculture rather than climate change (Butler, Boccacio, Gregory, Voříšek, & Norris, ; Eglington & Pearce‐Higgins, ; Jørgensen et al, ). However, in case of mountain birds, climate change can have a larger impact as the climatic niche of especially mountain specialists is shrinking, highlighted by the relatively fast declines of mountain species.…”

A near half‐century of temporal change in different facets of avian diversity

“…Changes in land cover (Mayfield et al, 2010;Jørgensen et al, 2016), introduction of exotic species (Sax & Gaines, 2003, anthropogenic climate change (Men endez et al, 2006;La Sorte & Jetz, 2010a;Jørgensen et al, 2016), and targeted conservation actions and federal efforts to restore critical habitats (King et al, 2006) might all have contributed to the observed increases in avian diversity. Similar increases were recently reported by Schipper et al (2016) for a slightly shorter version of the BBS dataset; that study, however, did not detect declines in biodiversity over the last decade.…”

Tracking Progress Toward EU Biodiversity Strategy Targets: EU Policy Effects in Preserving its Common Farmland Birds

“…We weighted the model by the inverse of the average standard error of the two population indices used to calculate growth rates to correct for the degree of uncertainty in the response variable (Jørgensen et al . ). The results of the model with the weights were qualitatively the same as of the same model without weighting, and here only the results of the weighted model are shown.…”