Ecological marginalization is widespread and increases extinction risk in mammals

Area of Science:

• Ecology
• Conservation Biology
• Biodiversity Research

Background:

• Human land-use change significantly impacts species' geographic ranges and realized niches.
• Species' realized niches can expand, shift, or contract under anthropogenic pressures.
• Ecological marginalization, where species are confined to niche extremes, is a consequence of range contraction.

Purpose of the Study:

• To investigate the effects of range contraction on niche space and habitat diversity in terrestrial mammals.
• To determine the prevalence and consequences of ecological marginalization driven by human land use.
• To assess the combined impact of range loss and marginalization on species' extinction risk.

Main Methods:

• Analysis of range and niche characteristics for 4,785 terrestrial mammal species.
• Quantification of niche space and habitat diversity loss associated with range contraction.
• Evaluation of the relationship between ecological marginalization, geographic range loss, and extinction risk.

Main Results:

• Range contraction in terrestrial mammals leads to significant loss of niche space and habitat diversity.
• Ecological marginalization is a common outcome of human-induced range contraction, displacing populations to niche extremes.
• Ecological marginalization is independently linked to poorer species performance and elevated extinction risk.
• Vulnerable groups, like large-bodied mammals and species with small ranges, face a compounded threat from range loss and marginalization.

Conclusions:

• Human land use drives ecological marginalization, a critical conservation threat beyond simple range loss.
• Conservation assessments must account for ecological marginalization to accurately evaluate extinction risks.
• Understanding and mitigating ecological marginalization is vital for effective species conservation and management strategies.