Bird population trends are linearly affected by climate change along species thermal ranges

Abstract

Beyond the effects of temperature increase on local population trends and on species distribution shifts, how populations of a given species are affected by climate change along a species range is still unclear. We tested whether and how species responses to climate change are related to the populations locations within the species thermal range. We compared the average 20 year growth rates of 62 terrestrial breeding birds in three European countries along the latitudinal gradient of the species ranges. After controlling for factors already reported to affect bird population trends (habitat specialization, migration distance and body mass), we found that populations breeding close to the species thermal maximum have lower growth rates than those in other parts of the thermal range, while those breeding close to the species thermal minimum have higher growth rates. These results were maintained even after having controlled for the effect of latitude per se. Therefore, the results cannot solely be explained by latitudinal clines linked to the geographical structure in local spring warming. Indeed, we found that populations are not just responding to changes in temperature at the hottest and coolest parts of the species range, but that they show a linear graded response across their European thermal range. We thus provide insights into how populations respond to climate changes. We suggest that projections of future species distributions, and also management options and conservation assessments, cannot be based on the assumption of a uniform response to climate change across a species range or at range edges only.

Changes in migration phenology and biometrical traits of Reed, Marsh and Sedge Warblers

“…Additionally, the observed increase in wing length might also reflect the fact that the size of the northern breeding populations has increased [e.g. 63], and/or that the reproductive success of birds breeding in northern areas can be greater [66].…”

Mitochondrial DNA and microsatellite markers evidence a different pattern of hybridization in red-legged partridge (Alectoris rufa) populations from NW Italy

“…Genetic homogenization is recognized as one of the most prominent threats to biodiversity, together with habitat loss and/or fragmentation, human disturbance, alien/invasive species (McKinney and Lockwood 1999), overexploitation of natural resources (Mack et al 2000;Olden et al 2004), and climate change (Thomas et al 2004;Jiguet et al 2010). The evolutionary role of natural hybridization as a source of new adaptive variations is still controversial (Barton 2001;Seehausen 2004).…”

Assessing the extinction risk of the great bustard Otis tarda in Africa

“…in Portugal, Turkey, Iran, Kazakhstan, Russia, China and Mongolia), where remnant populations are isolated and may suffer from a lack of genetic diversity (Pinto et al 2005, Tian et al 2006, Kessler 2007, Karakas & Akarsu 2009, Oparin et al 2013, Barati et al 2015. One possible explanation for this decline is that populations breeding close to the species thermal maximum have lower growth rates than those in other parts of the thermal range (Jiguet et al 2010).…”

“…It is estimated that a large proportion of bird species breeding in the western Palearctic may be threatened in the near future if global warming continues to increase (Huntley et al 2008). Furthermore, climate warming is expected to decrease population growth rates close to the warmest limit of a species' distribution, where climatic conditions are less suitable (Jiguet et al 2010). Thus, peripheral populations are likely to be most affected by changes in future environmental conditions (Brommer & Moller 2010).…”