Periodic Reporting for period 1 - RELOAD (Realised ecological niche and species distributions under global environmental change)
Reporting period: 2023-09-01 to 2025-08-31
Global environmental change, including land use change, climate change, pollution, and biological invasions, is causing accelerated rates of biodiversity change. Species are going extinct at rates of at least tens to hundreds of times higher than the average in the past 10 million years, while the geographical ranges of many others are contracting, shifting, and in fewer cases, expanding. Hence, we need to understand and predict how species are readjusting their geographical distributions in response to environmental change. Predictions are typically based on the modelled ecological niche, defined by the set of environmental conditions under which the targeted species has been recorded. However, these niche models are limited by the constrained spatio-temporal context of the data records, and thus their predictions do not account for the fact that the realised response of a species to the environment (i.e. their realised ecological niche) may vary in space and time. In this project, we studied how and why the ecological niche of species changes in space and time, how the magnitude of niche change varies among species, and how we can account for context dependence in niche responses to improve predictions about species distributions under global environmental change.
We assessed how the realised niche of species varies in space and through time at different temporal scales. We expect niches to change in space because of spatial non-stationarity and context dependence in species responses to the environment. Context dependence may arise due to frequent and widespread interactive effects of environmental drivers on species occurrence. Thus, accounting for interactions in species distribution models (SDMs) could in principle improve their transferability. We systematically assessed the extent to which interactions improve model transferability across taxa and biomes. Our study revealed that context dependence is hardly predicted via environmental interactions, suggesting that modelling routines should carefully consider their effect on the transferability of SDMs.
Then, we tested whether species are systematically changing their realised niches through time under ongoing global change, hypothesizing that even bird species cannot fully track their preferred environmental conditions due to the fast rates of environmental change. To this end, we assessed how environmental and distributional shifts have led to changes in the realised breeding niches of 121 species of North American birds over the last four decades and how the magnitude of niche change was associated with species traits. We found that the niche of 57% of the bird species diverged through time as they experienced widespread environmental change, including changes in both niche breadth and position. We concluded that bird species were in general increasingly exposed to higher environmental variation throughout their distributional ranges that led to changes in their realised niches over a relatively short time span (four decades), even though the niches of some species remained stable. The differences in the magnitude of niche change were to some extent related to species traits, which provided clues about how different species respond to widespread environmental change.
Finally, with the aim of investigating how the niches and geographical distributions of species have changed over a longer temporal scale, since before the onset of major anthropogenic impacts on biodiversity, we have participated in a major international effort to mobilise historical biodiversity data. In the context of an international workshop, we identified connections between historical ecology, biodiversity research and conservation by reviewing the main types of historical sources that contain biodiversity-relevant information and discussing how they can be extracted and integrated to draw inference about species, ecosystems and socio-ecological systems. We also proposed a strategy to improve the availability and use of historical data for biodiversity research and conservation. We are now using historical data since the sixteenth century to study how the distributions and niches of many species have been changing since times preceding the Industrial Revolution, and to set more appropriate biodiversity baselines for its conservation.
Then, we tested whether species are systematically changing their realised niches through time under ongoing global change, hypothesizing that even bird species cannot fully track their preferred environmental conditions due to the fast rates of environmental change. To this end, we assessed how environmental and distributional shifts have led to changes in the realised breeding niches of 121 species of North American birds over the last four decades and how the magnitude of niche change was associated with species traits. We found that the niche of 57% of the bird species diverged through time as they experienced widespread environmental change, including changes in both niche breadth and position. We concluded that bird species were in general increasingly exposed to higher environmental variation throughout their distributional ranges that led to changes in their realised niches over a relatively short time span (four decades), even though the niches of some species remained stable. The differences in the magnitude of niche change were to some extent related to species traits, which provided clues about how different species respond to widespread environmental change.
Finally, with the aim of investigating how the niches and geographical distributions of species have changed over a longer temporal scale, since before the onset of major anthropogenic impacts on biodiversity, we have participated in a major international effort to mobilise historical biodiversity data. In the context of an international workshop, we identified connections between historical ecology, biodiversity research and conservation by reviewing the main types of historical sources that contain biodiversity-relevant information and discussing how they can be extracted and integrated to draw inference about species, ecosystems and socio-ecological systems. We also proposed a strategy to improve the availability and use of historical data for biodiversity research and conservation. We are now using historical data since the sixteenth century to study how the distributions and niches of many species have been changing since times preceding the Industrial Revolution, and to set more appropriate biodiversity baselines for its conservation.
The project’s results advance our understanding of how species are readjusting their geographical distributions in response to global change. Because niche models are a widely used tool in conservation, the generated knowledge can be used to (i) predict the propensity of species for niche change based on general ecological characteristics that can be obtained for birds and many taxonomic groups, and (ii) provide realistic uncertainty boundaries when predicting future species distributions (the more the niche changes for a given species, the more uncertain the predictions will be). The results will expectedly contribute to understand and make better predictions of how biodiversity and respective ecosystem services are changing under climate and other global changes.