Title
Possible contemporary evolution in an endangered species, the Santa Cruz Island fox
Author(s)
Swarts H.M., Crooks K.R., Willits N., Woodroffe R.
Published
2009
Publisher
Animal Conservation
Abstract
An ability to mount rapid evolutionary responses to environmental change may be necessary for species persistence in a human-dominated world. We present evidence of the possibility of such contemporary evolution in the anti-predator behaviour of the critically endangered Santa Cruz Island fox Urocyon littoralis. In 1994, golden eagles colonized Santa Cruz Island, CA and devastated the predator-naïve, endemic island fox population by 95% within 10 years. In 1992, just before the arrival of golden eagles, foxes showed substantial diurnal activity, but diurnal activity was 37.0% lower in 2003-2007, after golden eagle colonization; concurrently, overall activity declined and nocturnal activity increased. Moreover, on nearby Santa Catalina Island, where golden eagles were absent but where the fox population recently crashed due to a disease epidemic, remaining foxes were significantly more diurnally active than were those on Santa Cruz Island. The weight of evidence suggests that the change in activity pattern was a response to predation, not to low population density, and that this was probably a heritable rather than a learned behavioural trait. This behavioural change may allow for prolonged island fox persistence, but also potentially represents a loss of behavioural diversity in fox populations. © Journal compilation © 2009 The Zoological Society of London.
Keywords
antipredator defense; behavioral response; diurnal activity; endangered species; endemic species; mammal; population density; raptor; species diversity; California; Channel Islands [California]; North America; Santa Catalina Island; Santa Cruz Island; United States; Aquila; Aquila chrysaetos; Canidae; Urocyon littoralis

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PUB11915