Ecological Determinants of Species Extinction Risk

Species extinction risk is shaped by a complex interplay between intrinsic biological traits and external environmental pressures. Intrinsic factors such as geographic range size, habitat specificity, life‐history pace and evolutionary history determine baseline vulnerability, while extrinsic factors – notably habitat loss, climate change, elevation gradients and human population density – modulate these vulnerabilities in space and time. Small‐ranged specialists with narrow thermal or dietary niches often succumb first to alteration of their habitats, whereas generalists with broad ecological tolerances may persist. However, even widespread species can enter decline under sustained anthropogenic pressure. Elevation influences risk by imposing physiological constraints and reducing reproductive windows, as observed in montane amphibians. Marine organisms face additional dynamics, with exploited taxa exhibiting shifts in distributional hotspots and trait‐based resistance to environmental change. Integrating trait data with demographic and spatial analyses has advanced predictive frameworks, allowing conservationists to identify at‐risk taxa before they reach crisis thresholds. This trait‐centred, multistressor approach has global relevance for prioritising conservation action and forecasting biodiversity loss under continuing human impacts.

Research from Nature Portfolio

Recent studies have expanded our understanding of how ecological traits and environmental settings forecast extinction vulnerability across both marine and terrestrial realms. Analyses of exploited marine bivalves reveal that larger body size, shallow‐water occurrence and extensive geographic and thermal ranges tend to confer resistance to extinction, yet certain tropical and temperate faunas harbour exploited species with high intrinsic vulnerability. Mapping these trait‐based metrics highlights shifting hotspots of concern, notably from the northeast Atlantic to the west Pacific, and informs regional management priorities. A global spatial assessment of terrestrial threatened species richness demonstrates that, after accounting for overall species richness, environmental variables such as temperature and island size often outweigh direct human impacts in explaining broad patterns of threat. Nonetheless, variation among vertebrate groups indicates that human pressures remain critical in specific regions. This framework integrates environmental and anthropogenic drivers to guide the identification of conservation hotspots and to forecast how threatened assemblages may reorganise under ongoing global change.

Ecological Determinants of Species Extinction Risk publication trend

The graph below shows the total number of articles in ecological determinants of species extinction risk across all publications each year (not limited to Nature Index journals).

Technical terms

Intrinsic traits: Biological characteristics of a species (e.g. body size, fecundity, evolutionary lineage) that influence its baseline vulnerability to extinction.

Extrinsic threats: External environmental or anthropogenic pressures (e.g. habitat loss, climate change, invasive species) that drive declines beyond a species’ intrinsic resilience.

Geographic range size: The total area over which a species is distributed; smaller ranges generally correlate with higher extinction risk.

Niche breadth: The diversity of environmental conditions or resources a species can utilise; specialists with narrow niches face greater vulnerability.

Anthropogenic drivers: Human‐induced factors (e.g. land‐use change, exploitation, pollution) that increase extinction risk by altering habitats and ecosystem processes.

References

1. Diversity, distribution and intrinsic extinction vulnerability of exploited marine bivalves. Nature Communications (2023).
2. More losers than winners: investigating Anthropocene defaunation through the diversity of population trends. Biological Reviews (2023).
3. Risk of extinction increases towards higher elevations across the world's amphibians. Global Ecology and Biogeography (2023).
4. A global assessment of the drivers of threatened terrestrial species richness. Nature Communications (2020).
5. A review of the relation between species traits and extinction risk. Biological Conservation (2019).
6. Trait-based prediction of extinction risk across terrestrial taxa. Biological Conservation (2022).