Friday, September 21, 2018

FIF Research Grant to Investigate Island Fox Diet Through Whiskers

photo courtesy of P. Bronstein
Island foxes have lots of long black whiskers. These specialized hairs hold important information on diet that could inform decisions on island fox conservation.

Friends of the Island Fox is happy to announce: 

Juliann Schamel is the recipient of the first FIF Research Grant

Schamel is a Biological Science Technician at Channel Islands National Park and the $5,000 grant will help fund research on "The Channel Island Food Web–A Decade of Dietary Resource Use in Channel Island Fox: Implications for Reproduction, Recruitment, and Resilience in a Changing Climate."

It's a big title reflecting the broad range of important data that may be revealed. 

Schamel's work will build on important past research.

island fox scat (or poop)
In 2009, researchers collected island fox scat samples to look at seasonal diet across all six islands. Their 2014 paper revealed diet varied from island to island and included a higher frequency of insects and fruit than expected. They cautioned that islands with poor native plant diversity offered fewer food options for island foxes in the event of drought. 

photo courtesy of P. Bronstein
Just as the science warned, during the consecutive years of the recent drought, island foxes were challenged to find enough food on San Miguel and San Nicolas Islands. Decline of San Nicolas Island fox. During this time a new parasite entered the San Miguel Island fox's diet causing fox deaths.

While scat successfully reveals visual items, (insect exoskeletons, cactus fruit skin and seeds), it may not visually capture everything in the fox's diet. Also, scat data is limited to recording diet in an individual over a short time period, a few days.

In 2010, building on work done on the San Joaquin kit fox, a small sample of island fox whiskers were investigated using stable isotope analysis. 

You are what you eat. Food items (prey and plant) have their own isotope fingerprint. Carbon and nitrogen isotopes consumed by the fox are laid down in the hair shaft documenting an individual's diet over months. 

Since 2010, biologists have been gathering whisker samples from individual island foxes during health checks on the northern islands. These samples have been cataloged by year and with individual fox identification. 

FIF is excited to support Schamel's research using whiskers because it has the potential to:
  • Compare diet between successful mothers and unsuccessful mothers
  • Discover dietary differences between coastal living island foxes and interior living foxes
  • Document changes in diet over the past 9 years, through the drought and as the fox populations have grown
  • Possibly reveal prey items that are a vector for the intestinal parasite on San Miguel Island which has caused fox deaths
Whiskers are amazing! Not only do they offer an opportunity to invest in greater knowledge about the secret lives of island foxes, whiskers grow back and their collection is non-invasive. 

FIF will be bringing you more on Juliann Schamel and her research as her work progresses.

Thank you to all of the 2018 grant applicants for sharing your research goals with FIF. There is so much more to learn about island fox health, behavior, and interactions with other species.

Application for the 2019 Research Grant
will be available April 15, 2019