Describing Diet of Imperiled Sierra Nevada Red Foxes and a Carnivoran Competitor Using DNA Metabarcoding

Area of Science:

• Ecology
• Conservation Biology
• Wildlife Management

Background:

• Montane red foxes (Vulpes vulpes ssp.) are of conservation concern due to narrow ecological niches and isolated populations.
• Limited understanding of montane red fox ecology hinders effective conservation strategies.
• Coyotes (Canis latrans) are expanding their range and may compete with montane red foxes.

Purpose of the Study:

• To investigate the diet of Sierra Nevada red foxes (V. v. necator) in an understudied region.
• To assess dietary overlap between Sierra Nevada red foxes and coyotes.
• To inform conservation and management of imperiled montane red foxes.

Main Methods:

• Scat samples from Sierra Nevada red foxes and coyotes were collected using detection dog surveys in Oregon, USA (2017-2018).
• DNA metabarcoding was employed to identify prey species composition in scat samples.
• Dietary overlap was quantified using Pianka's index based on weighted and frequency of occurrence.

Main Results:

• Sierra Nevada red fox diet was primarily golden-mantled ground squirrels (Callospermophilus lateralis), while coyotes consumed more snowshoe hares (Lepus americanus).
• Both species exhibited similar prey taxonomic richness.
• High dietary overlap (Pianka's index = 0.74 weighted, 0.69 frequency) was observed, with golden-mantled ground squirrels being a crucial prey for both.

Conclusions:

• High dietary overlap indicates potential interspecific competition between Sierra Nevada red foxes and coyotes.
• Increased spatial overlap could lead to niche compression for the endangered Sierra Nevada red fox.
• Findings address data deficiencies and support conservation planning for this imperiled species.