Friday, March 22, 2019

Island Fox Whiskers Go to the Lab

Schamel with island fox following the fox's health check.
FIF Research Grant recipient Juliann Schamel has been collecting island fox whiskers to study the diet of island foxes through stable isotope analysis. Her research project is in conjunction with Dr. Seth Newsome and the Center for Stable Isotopes at the University of New Mexico.

Juliann says "Once I learned how stable isotope ecology works and what we could learn about island fox ecology from this method...I was hooked. The invisible chemical world can reveal fascinating connections within food webs and beyond." More on stable isotopes

"This year, with the support of Friends of the Island Fox and [another conservation fund], we are able to investigate a variety of conservation-geared questions about island fox diet on San Miguel and Santa Rosa Islands. We are looking into how diet differs among habitats on the islands, among demographic groups, and between island fox and island skunk. We are also assessing if and how fox diet has changed over time (2010–present) in response to things like density changes in the fox population and rainfall (drought conditions). This last question may have important implications for the ecology of the acanthocephalan worm, a novel parasite that appeared in the San Miguel Island fox in 2012 (at the beginning of the drought) and has spread through the fox population."

The spiny-headed worm, a species of Acanthocephala, has been implicated in the low population numbers on San Miguel in recent years. Parasite threatening San Miguel Island Fox.

"By using whisker samples that are linked to a known individual with a known history within the island fox monitoring program," Schamel says, "we are able to track the diet of individuals over time to see if and how their diet may have fluctuated during the drought or as they moved to a new habitat."

A number of whisker specimens were collected this winter, including in the beach/dune habitat on Miguel and Rosa where island foxes are not typically counted. This will provide data on dietary resources in the marine adjacent habitat that has not been collected before. Schamel says "I am very excited to run these samples!"


Collected whisker samples are sorted, inventoried, and cataloged. Once they are cleaned, rinsed, and dried, each individual whisker is placed in vial.


Newsome and his lab manager at UNM use a razor and tweezers to divide each whisker into sub-samples: 0.2mg (weighed precisely with a micro-scale).

Schamel explains these sub-samples are fed into "the mass spectrometer, which consumes the samples and spits out data on carbon and nitrogen isotope ratios." The ratios are compared to a library of food resources and their known isotope ratios. "The FIF funding is actually paying the mass spectrometer for its time."

Schamel in the field on Santa Rosa Island.
So far ~100 island fox samples from Santa Rosa have been analyzed from a variety of habitats. In addition ~200 island fox whisker samples from San Miguel have been analyzed from 2010–2012, before the drought. Schamel will be at UNM this spring working on samples from 2014–2016. "There are many samples from the same individuals across this time frame, which will be exciting to see!"

Juliann Schamel hopes to present preliminary data at the 2019 Island Fox Conservation Working Group Meeting in May. 

Research like Juliann Schamel's is vital to understanding island fox health and long-term survival.  This research is only possible with donations from people like you.

Applications for the 2019 Friends of the Island Fox Research Grant will be available on islandfox.org on April 15, 2019.