North American crayfish introduced to Britain now threaten native species

Recent shifts in bird populations across North America are primarily driven by the combined effects of climate change and land use change, according to new research. An extensive analysis of 159 bird species, spanning the years 1995-2019, revealed that climate change has adversely impacted 90% of these species, while land use change has negatively affected 96%.

The study utilized a Bayesian framework to conduct counterfactual simulations, fitting dynamic occupancy models to long-term survey data. This approach allowed researchers to quantify the predictive performance and assess the relative importance of each driver, accounting for model accuracy. The findings suggest that climate change has a more significant role than land use change in influencing bird occupancy across the board.

Nonetheless, the effects of both drivers were largely antagonistic rather than additive or synergistic, meaning that their combined impact was more complex than the sum of their individual effects. Notably, climate change was the dominant factor in shaping bird communities in the western United States, while land use change took precedence in the southeastern region.

In the northeastern part of the country, the interplay between climate and land use change dominated the picture. The study underscores the importance of considering multiple global change drivers in concert when examining recent alterations in North American bird distributions. Importantly, this research highlights that the impacts of climate and land use change on bird occupancy dynamics cannot be understood by studying each driver in isolation.

By disentangling the effects of these factors, impact attribution approaches can enhance our understanding of global change impacts, thereby informing conservation planning and providing more accurate projections of biodiversity responses to global change.