FIF 2024 Research Grant Investigating Link Between Island Fox Genetics and Health

Meet Kimberly Schoenberger, recipient of FIF’s 2024 Island Fox Research Grant and a PhD candidate at the University of Southern California (USC) Dornsife College of Marine and Environmental Biology.

Schoenberger is initiating the first investigation of island fox genetics using transcriptomics. This leading-edge research uses RNA (the copier of DNA) to look at a species’ genetic material and evaluate it for protein production and vital cell functions. Transcriptomics provides insight into how genes turn on or off in cells and how this may influence health or disease.

 

The project will analyze three important aspects of island fox genetic expression: 1) what are the genetic differences between the six island fox subspecies; 2) how do different environmental conditions and demographics impact gene expression; and 3) will identify genes that are being influenced by disease or parasite exposure.

(As Catalina Island foxes were recovering from a severe population low, they experienced high levels of cancer due to an extreme immune system response to ear mites. This condition does not occur on other islands. Dr. A. DeCandia’s microbiome investigation identified a connection with specific bacteria (elaborated on by Jasmine Lu paper). Husbandry efforts currently control the ear mites, but the epigenetic link between the inflammation and eventual cancer remains unknown.)

Disease and parasites pose some of the greatest current threats to island fox survival. This project could provide valuable insight into which island fox subspecies have the greatest genetic vulnerabilities and help inform conservation measures.

Another important element of Schoenberger’s project is that it integrates directly into the current protocols for health checks. Biologists are currently in the field across the Channel Islands counting island foxes, providing health checks, and administering vaccinations. As part of the 2024 health checks, some individual island foxes will provide a blood sample for transcriptomics. Schoenberger’s genetic study will compliment and build on the individual island fox data currently being collected on diet, microbiome, territory, and health.

Schoenberger was able to travel out to Santa Rosa Island and engage with the National Park biologists as they took samples. She also met individual island foxes that will be part of her investigation.

At USC, Schoenberger explains that she puts the blood samples through a centrifuge “to separate RNA from other particles.”

The samples then go through a chemical processing to isolate and purify the RNA for sequencing.

Schoenberger says: “Transcriptomics can allow insights into gene expression patterns that underlie population health and disease by providing molecular-level understanding of island fox physiology and how they function and respond to differing environmental conditions.” Friends of the Island Fox is thrilled to support Kimberly Schoenberger’s research which will provide a baseline on the differences between populations and “shed light on key genes that are affected by environmental differences and may be crucial for adaptation and survival of the island fox.”

Your donations make this research possible.

photo courtesy of P Bronstein

 

Island Foxes Teaching the Next Generation of Field Biologists

For the past two years, Friends of the Island Fox has had the honor of funding all of the new and refurbished fox tracking collars for Santa Cruz Island–but this summer, these collars were able to support more than just island fox monitoring and research.

 

As part of Paso Robles High School's Field Studies Collaborative program, a group of 25 students ranging in age from 15–18 spent a week on Santa Cruz Island, learning about its history and ecosystems. The program includes student presentations, expert workshops on a variety of topics, and field experience, like vegetation sampling and plant identification.

 

This past year, FIF board member Justin Purnell expanded the program to include trapping and working with island foxes, giving students an opportunity for hands-on experience working with the island's (very adorable) apex predator.

Justin isn't new to Paso High's program. Taking the class, during his junior year at Paso High, inspired his own path forward in wildlife biology. Since then, he has been a volunteer and chaperone on the trip, which is now in its 34th year.

 

The students (and other chaperones) were blown away by the experience of working with the island foxes. For many of the students, it was their first time seeing wildlife up close–and the impact cannot be overstated. Some were moved to tears and many of them expressed an interest in continuing their education in not only wildlife biology, but a host of other careers that support conservation.

Here are some of their reactions, in their own words:

• "Working with those foxes was such an amazing experience and changed my life. I thought I had my future figured out, but seeing what Justin does on the island threw a wrench in my plans. Now I think I want to go to college and study forestry. I would never have looked into or even thought about this as my career path if I didn't go on this trip." - Hannah, 16
• "It was hard to believe that doing something so special as a career could be more than a dream, but after getting to experience working with the foxes firsthand, I now know that doing work like this could be my reality." - Jordan, 17
• "It was incredible to see the foxes close up and to be a small part of helping to preserve this endemic species. This is one of the coolest things I've ever gotten to do, and it really drove home for me the importance of preserving nature. I get emotional thinking about it! I am forever grateful for this experience." - Ava, 15
• "When I was younger, I was absolutely obsessed with animals and was set on working with them as an adult. As I grew up, I lost faith that I would be able to have a stable career working with wildlife. Watching Justin work was super emotional because I felt that love and interest in wildlife return. This trip totally changed my plans for my future–I am now planning to go into wildlife conservation." - Divy, 17
  

 

These experiences, and the impacts that can ripple out from them, are the reason that we do this work. We are happy that our funding of the collars was able to help support this experience for Paso High's field studies program and are excited to find other ways to support both the island foxes and the next generation of wildlife conservationists. Article by Justin Purnell 

Island Fox F257 is Back and Beautiful at Middle Age

 

F257 August 2024

Channel Island National Park biologists are on Santa Rosa Island this week capturing island foxes, counting them, checking their health, and updating radio-tracking collars. Biologist Juliann Schamel contacted FIF with great news: Female island fox 257 was captured for the 5th year in a row and she's looking great! Here's Juliann's update:

F257 was born in 2019, and has spent her entire life in her natal area, which overlooks the East Point estuary [as] Santa Cruz Island floats on the horizon.  Every year since 2019, she has gone into traps at our long-term monitoring site at Old Ranch.  She has spent a total of 18 nights in our "island hotel."  Every year, she moves between Trap 1, Trap 11, and Trap 12, which are in a triangle 200 meters apart from each other.

F257 is five years old now, and remains in great health.  She has been monitored with VHF collars throughout her life, and is currently wearing her third collar.  She has Age Class 2 tooth wear.  As an adult, she has fluctuated in weight between 1.8–2.2 kilograms (4–4.9 pounds). 

 

island fox whisker sample

This year, during her health check ... she also contributed samples to microbiome, leptospirosis, and stable isotope research (gut swab, urine, and whiskers).

 

In 2023, she had signs of nursing pups for the first time.  This year she does not show signs of having had pups.  (As pictured, her belly is white.) Data from our long-term monitoring sites has allowed us to document fox recovery to carrying capacity, which was reached in 2020. (What is carrying capacity?) 

 

Since then, the population has displayed density-dependent reproductive suppression (which I think is SO COOL!!!!) - very few pups were weaned in 2021, 2022, and 2023, adult survival remained high, and the total population has remained around 2,500.  Collecting long-term data during this time period has allowed us to document which adult females reproduce and which do not in this high-density landscape (how old are they? what habitat do they live in? how dense are the foxes in their local area?), which will provide further insight into what environmental factors influence fox biology, and how fox ecology in turn influences the landscape.  Old Ranch, where F257 lives, has a high density of adult foxes with high survival, and this area has not produced many pups in the past several years.  With the VHF collar, we will be able to monitor F257's health and status for years to come!

It's been so lovely to see F257 again! - Juliann Schamel

Schamel is not only a fox biologist out on the northern Channel Islands, she's also researching the complex interactions between island foxes and the landscape on Santa Rosa Island. 

 

"Date with a Fox" with Juliann Schamel

More on island fox density

Your Donations funded F257's radio collar and 

vaccinations for rabies and distemper!

FIF 2024 Trip To Santa Cruz Island

What do these smiling people have in common?

 

They joined Friends of the Island Fox on a trip to Santa Cruz Island

Join in the Fun and Experience Island Foxes in the Wild

 

Saturday, September 14, 2024

We'll check-in at Ventura Harbor at 8 am 

and return around 5 pm

The $78 registration fee includes: boat fare, FIF naturalist guides on the island, and a donation to support island fox conservation. 

Trip is Sold Out

 It's a full day of exploring Santa Cruz Island and each trip has unique experiences.

an island fox follows a raven

watching an island fox

 

 

The endemic island scrub jay is now easily seen in the Scorpion Landing area where we are headed. Late summer is also a great time to see marine mammals.

Reservations are taken on a first come basis. For more info follow the button...

Trip is Sold Out

 See island foxes, experience the Channel Islands, and support important conservation.

Fox Foto Friday - Island Foxes Being Counted

 

What's the word from the northern Channel Islands?

NPS biologist Juliann Schamel says the "season is going well so far, we just caught our 100th fox of the season yesterday!"

If you look closely, you can see the dark squared-off battery end of a radio collar beneath the chin of the captured island fox.

Friends of the Island Fox funded its 417th radio-tracking collar last month. New radio collars arrived for deployment on three islands!

Your donations provide radio collars to monitor island fox survival. Help Island Foxes

More about how biologists capture island foxes for health checks 

Radio Collars Arrive for Summer Health Checks!

You Did It!

 

These refurbished radio collars are being prepared for deployment during island fox health checks on San Miguel Island in the next few weeks.

The Channel Islands National Park fox biologists tie bright pink ribbons on radio collars and mark the ribbon with the collar's ID number and radio frequency. Pink makes it easy to find the collar in a dark backpack. The ribbon can quickly be removed and the information on it entered into field notes, after the island fox has been released.

 

Having the info on the ribbon helps the biologist minimize the time they spend physically in contact with the island fox.

 

Island foxes do not have to be tranquilized during health checks. Special muzzles that cover their eyes help to keep them calm. However, it is a priority that wild island foxes are handled only when necessary and for the shortest amount of time possible.

 

Donors like you funded:

• 26 refurbished radio collars 
• 20 new radio collars
• and $1,036 in rabies vaccine (to vaccinate 650 island foxes)
  

that arrived this month for deployment across San Miguel, Santa Rosa, and Santa Cruz Islands. Rabies vaccinations will also protect Santa Catalina Island foxes.

Radio collars monitor island fox survival

More about island fox health checks

Fox Foto Friday - Island Foxes as Seed Dispersers

What do these year-old toyon lemonadeberry plants have in common?

They were grown from seeds found in island fox scat. 

FIF talks about island foxes eating native plant fruits and spreading the seeds across the islands, but now there is scientific evidence that this seed dispersal can help island plants.

Researchers Savannah Bartel and John Orrock from the Univ. of Wisconsin, Madison, were investigating the role social status plays in vertebrate dispersal of seeds. They found that while passing through the digestive system of a fox or coyote didn't necessarily improve germination, being in carnivore scat provides seeds with protection. Rodents tend to avoid carnivore predators and their poop.

To do her own observations, Juliann Schamel, with Channel Island National Park, collected island fox scat with lemonadeberry seeds and attempted to grow them. And they grew! 

 

The plants are growing in an island nursery in collaboration with Michelle Gados and Kathryn McKeachern, who are working to restore Santa Rosa Island's unique cloud forest plant life.

Does passing through the island fox's digestive tract provide other benefits to seeds? More investigation is needed.

Island fox's eating toyon berries and other native fruits are providing seeds with a protective compost pile to grow in. 

toyon berries

Fox Foto Friday - Keeping Vaccines Cool

How are colorful cooler bags and ice packs helping island foxes?

 

Biologists at Channel Islands National Park will soon be heading out into the field to count island foxes and provide health checks. Part of that effort includes vaccinating island foxes and taking blood samples.

 

 

Vaccines need to be kept cool going out into the field and biological samples need to be kept cool coming back.

To maintain biosecurity for each island and reduce the opportunity for insects, viruses, parasites, or plant seeds to hitch a ride and move from one island to another, FIF has supplied the biologists with two cooler sets per island. Cooler packs dedicated to use on a specific island will help keep island foxes safe.

 

$1,036 of rabies vaccine is on its way to four islands for 650 island foxes. 

Your donations help protect island foxes.

Help FIF raise the additional $7,000 to pay for this year's canine distemper vaccine.

Island Fox Status Update 2024

In 2023, island fox populations remained healthy and stable across all six islands. Weather extremes, however, effected islands in different ways.

Island fox on San Clemente Island courtesy of J. Sanchez

The following is an update across the Channel Islands from notes compiled by Friends of the Island Fox at the Island Fox Conservation Working Group Meeting May 8, 2024 hosted at the Santa Barbara Zoo (hybrid meeting).

Reported population numbers are the official estimates submitted by the land managers and calculated by them from island foxes captured for health checks July–December 2023. (How island foxes are captured and given health checks)

Overview: Rainfall was abundant in 2023, but the impact on plant and prey species varied by island. Island fox populations on smaller islands grew, while island fox numbers on larger islands adjusted downward slightly. The anomaly was Santa Cruz Island, which appears to have experienced a significant population increase, creating a historic record for a single island population.

Range Size and Diet Research: Ongoing research by FIF Research Grant recipient Katie Elder revealed that fox home ranges on Santa Rosa Island have declined in size by 83% since 2009. It's not surprising that home range territories have gotten smaller as the fox population has recovered from less than 400 individuals to over 2,500. The surprise is how strictly the 15 male foxes monitored for a year with GPS collars stayed confined within their small territories. This means that individuals in poor habitats have less access to varied resources; inland foxes aren't accessing beach foods and individuals with grassland home ranges may have less access to fruiting plants. How will individual survival be challenged if drought conditions return?

Density: On the northern islands, island fox density has become high: 11.35–14 island foxes per square kilometer. What is island fox density? While it's great to see increased populations of island foxes, high density means individual fox territories are close together. Disease can be transmitted more easily through a dense population. As the Range Size research reveals, high population density may also mean island foxes have less flexibility to survive fluctuations in their available resources.  

Climate Impacts: For the first time, islands documented increased rainfall that did not coincide with island fox population growth. The timing of storms or extreme high levels of rain may have negatively impacted deer mouse or insect populations resulting in fewer resources for island foxes.    

In 2024, the leading threats to island foxes are:

• biosecurity: the threat of introduced viruses, accidental transportation of a deadly parasitic worm from San Miguel Island to other islands, disease, and/or non-native animals
• reduced funding for monitoring
• climate change: extreme weather effects food resources, heightens parasites, challenges health, and can make it more difficult for biologists to access the islands
  

Greatest Concern: Biosecurity threats are heightened by the high density of island foxes on northern islands and rising tourism on Catalina Island. Canine distemper and other dog diseases remain threats. A new investigation has identified the parasitic spiny-headed worm on San Miguel Island that has caused fox fatalities in the past, especially in drought years. The investigation to find the prey species that acts as an intermediary host continues. New findings reveal that this lethal intestinal parasite was most likely transported to the island by humans. It is vitally important that this parasite not be moved to other islands.

Be a BioSecurity Guardian–Clean, Check, and Close everything you take to the islands. Watch Biosecurity Video.

Smaller Islands

San Miguel and San Nicolas Islands appear to have equally benefited from additional moisture and available resources. Their populations grew at the same rate in 2023. San Clemente Island remained stable at its lower population size.

San Miguel Island (lime green line): While adult annual survival declined, healthy pups stabilized and increased the population. This island currently has the greatest island fox density: 14 foxes per square kilometer.

San Nicolas Island (pink line): General health remains good, but lifespan appears to be 7–8 years, rather than the 10–12 years on larger islands. Density remains moderate at 8.4 foxes per sq km. Dog flu has declined, but remains prevalent. Car strike causes the greatest island fox mortality and more days of foggy weather increased fox fatalities.

San Clemente Island (blue line): Adult island foxes on this island had a high 89% chance of surviving the year, but pup survival continues to be investigated. This island currently has the lowest fox density: 4.06 foxes per sq km. Approximately 5% of the population is lost annually to car strike and inexperienced young island foxes are more likely to be hit.

 

Larger Islands

The larger islands were all thought to have reached carrying capacity. Santa Catalina and Santa Rosa Islands adjusted downward at nearly the same small rate in this extremely wet year. Because their populations are so large, this adjustment is not unexpected. Santa Cruz Island, however, increased at the same high rate as the small islands, creating a historic population estimate.

Santa Catalina Island (red line): The population remained stable with a density of 9.22 foxes per sq km. Analysis of tick samples collected from island foxes from 2019–2022 showed no tick-borne disease. This is important because 60% of Catalina Island foxes carry ticks. Both dog flu and corona virus declined in 2023, but biosecurity remains a huge concern on this island. From car strike and dog attack to foxes being drown in scuba wash tanks and entrapped in human structures, humans and pets currently pose the greatest threat to island foxes. In 2023, over 62% of known fox fatalities were human caused.

Santa Rosa Island (pink line with black centers): This population remains stable with a high density of 11.35 foxes per sq km and adults had an 89.5% chance of surviving the year. Research is showing that Rosa foxes are becoming dietary specialists. How will this impact individual foxes and the island ecosystem?

Santa Cruz Island (black line): With an adult annual survival rate of 94.7%, this island was estimated to have a historic population size of 4,057. The fox density is currently 12.9 foxes per sq km. Due to a record 35 inches of rain, foxes could not be counted in some of the traditional grid locations. There is a possibility that the high population calculation may be slightly inflated by data fluctuations.

Weather has a profound effect on island resources. Changing weather patterns–tropical summer storms, extreme winter rainfall, increased summer heat, denser fog–all impact island habitats and island foxes. 

Your donations help monitor island fox survival with radio collars and provide vaccinations to protect them from introduced disease. Research is investigating health, behavior, and how best to support stable island fox populations in a changing world.

Healthy island fox populations depend on people like you supporting conservation efforts. 

 

What is Island Fox Density?

 

Density is a term used in biology to express the number of individual living things in a given area. Biologists use a defined area size–ie. a square meter, square kilometer or square hectare–to quantify density. 

A square kilometer is equivalent to the footprint of Disneyland in southern California and a square hectare is equivalent to a professional baseball field.

Understanding how many island foxes are living in a square kilometer is part of the calculation for estimating the size of an island-wide population.

At the recent Island Fox Conservation Working Group Meeting, land managers reported on the island fox density for their islands. There was a noticeable difference between northern and southern islands.

Northern islands are reporting considerably higher island fox density. The causes for this are not completely clear. Northern islands may benefit from less extreme weather–higher average rainfall and more moderate summer temperatures–which support diverse prey and plant food for island foxes. Northern islands also have fewer impacts from humans; Catalina Island and the two Navy islands, San Clemente and San Miguel, have roads and cars that cause the highest percentage of fatalities for island foxes. 

High density, however, can have a downside. Catalina Island has been stable for the past 10 years with a density around 9 foxes per sq km. The island with the highest density in 2023–14 foxes per sq km–was also the smallest, San Miguel Island. When density increases, individual island fox territory decreases. A smaller territory means a smaller area to find food. High density can push some individuals into habitats with fewer quality resources. San Miguel's resources are less diverse than the larger islands and there are fewer options for foxes when drought or other weather extremes occur.

 

When island foxes are living closer to each other, the possibility of disease moving rapidly through a population also becomes heightened. Parasites can spread more easily.

Understanding population density is important for calculating risks to populations and making informed conservation decisions.