Old-growth forests buffer climate-sensitive bird populations from warming

Aim: Habitat loss and climate change constitute two of the greatest threats to biodiversity worldwide, and theory predicts that these factors may act synergistically to affect population trajectories. Recent evidence indicates that structurally complex old-growth forest can be cooler than other forest types during spring and summer months, thereby offering potential to buffer populations from negative effects of warming. Old growth may also have higher food and nest-site availability for certain species, which could have disproportionate fitness benefits as species approach their thermal limits. Location: Pacific Northwestern United States. Methods: We predicted that negative effects of climate change on 30-year population trends of old-growth-associated birds should be dampened in landscapes with high proportions of old-growth forest. We modelled population trends from Breeding Bird Survey data for 13 species as a function of temperature change and proportion old-growth forest. Results...