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| 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. | |
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