Mapping differences in mammalian distributions and diversity using environmental DNA from rivers

Area of Science:

• Ecology
• Conservation Biology
• Molecular Ecology

Background:

• Efficient monitoring of mammalian communities is crucial for effective conservation and management.
• Environmental DNA (eDNA) analysis of river water shows promise for biomonitoring mammal populations.
• Previous eDNA studies primarily focused on species detection, with less emphasis on community diversity and structure.

Purpose of the Study:

• To assess the sampling effort needed to map mammal diversity and distribution using river eDNA.
• To infer community structure, including species richness and beta-diversity, of semi-aquatic and terrestrial mammals.
• To evaluate eDNA metabarcoding for rapid detection and understanding of mammalian community dynamics.

Main Methods:

• eDNA metabarcoding of river water samples from two rivers in southeastern England.
• Analysis of species accumulation curves and occupancy modeling to determine sampling effort.
• Assessment of community diversity using species richness and beta-diversity metrics, partitioned into nestedness and turnover.

Main Results:

• eDNA metabarcoding detected 25 wild mammal species (82% of expected), including rodents, deer, lagomorphs, and carnivores.
• Sampling effort varied by mammalian order; common species were more readily detected than carnivores.
• Species richness differed between rivers, and beta-diversity patterns highlighted species replacement within rivers and species loss between them.

Conclusions:

• eDNA metabarcoding is a capable tool for rapidly detecting mammal species and inferring community composition.
• The findings provide insights into mammalian community dynamics across spatial scales, informing future biomonitoring strategies.
• This study underscores the utility of eDNA for comprehensive mammalian community assessment and conservation planning.