Diverse strategies for tracking seasonal environmental niches at hemispheric scale

Abstract

AbstractAimSpecies depend upon a constrained set of environmental conditions, or environmental niches, for survival and reproduction that are being increasingly perturbed or lost under rapid climatic change. Seasonal environments, which require species to withstand shifting conditions or track their niches via movement, can offer an important system to study the range of biological responses to potentially cope with climate change. Here, we develop a novel methodological framework to identify niche‐tracking strategies, including the tracking of niche position and breadth, using a uniquely well‐sampled system of 619 New World bird species.LocationWestern Hemisphere.Time period1980–2020.Major taxa studiedBirds (Aves).MethodsAt continental scales, we identify the tracking of both environmental niche position and breadth and assess its phylogenetic and functional underpinning. Partitioning niche position and breadth tracking can inform whether climatic means or extremes constrain seasonal niches.ResultsWe uncover four primary niche‐tracking strategies, including the tracking of environmental niche position, niche breadth, both or neither. Species that track niche position most often also track niche breadth, but nearly 40% only track one component and 26% only track niche breadth and not position. There is only limited phylogenetic determinism to this variation, but a strong association with ecological and functional attributes that differs between niche position versus niche breadth tracking.Main conclusionsThe observed diversity in type and strength of environmental niche‐tracking strategies points to highly differing sensitivity to ongoing climatic change, with narrow trackers of both position and breadth particularly susceptible. The trait associations of niche tracking imply significant functional consequences for communities and ecosystems as impending climate change affects some strategies more strongly than others. Seasonal environments and their diversity of niche‐tracking strategies offer exceptionally dynamic systems for understanding the biological responses and consequences of climate change.