The
Recovery of the Santa Rosa Island Fox
By
Kevin Poindexter
Description
and Ecology:
For
my organism I chose one of the six subspecies of Island fox located on the
Channel Islands. Out of the six choices
I went with the Santa Rosa Island Fox. Each Island has its own subspecies of
the fox with slightly different characteristics than the rest. It is important
to note that the Island fox is smaller and colored differently than the
mainland Gray Fox. According to the information I found on the FWS website, the
Santa Rosa Fox is about the size of your average housecat. The website talks
about their coloring which typically ranges from gray to brown which gives them
a kind of rusted look. According to research males tend to be larger than
females. They typically weigh 4-7 pounds, further dimensions are given on the
FWS site (FWS).
Picture
from Nation Park Service Website
Geographic
and Population Changes:
As
I learned in wildlife conservation biology, in order to properly list a species
there must be data that clearly demonstrates a drastic population decline in
that species. As I stated above these kinds of fox only occur on six of the
eight Channel Islands and nowhere else in the world. The Channel Islands
stretch up the cost of Southern California. For the subspecies I chose they are
found only on Santa Rosa Island which is technically a portion of Santa Barbara
County. While researching the Santa Rosa Island Fox I found the data marking
their decline but the recovery plan is actually for 4 of the 6 Island fox so I
was able to find data on the decline of all 4 species. The following data is
obtained in the recovery plan on the FWS site, “San Miguel Fox: 450
individuals- 15 Individuals, Santa Rosa Fox: 1750- 14, Santa Cruz Fox: 1450-55,
and Santa Catalina Fox: 1300-103.” This data shown clearly demonstrates a
significant population change which is an important aspect in the criteria needed
for a species to be listed.
Simple
Map of Santa Rosa Island obtained from Wikipedia.
Listing
Date and Type of Listing:
This
subspecies of Island Fox was listed on March 6, 2004. It had raised some
awareness that they were becoming less and less evident before this date but
perhaps there was not enough proof in order to justify listing quite yet. It is
still listed as endangered on the ESA but I was happy to read and hear in class
that the recovery plan has been quite effective since it was put into action.
Cause
of Listing and Main Threats to Existence:
Researchers
have concluded that the main reason for the population decline of these Island
Fox was due to predation by Golden Eagles. Before the effects of DDT Golden
eagles were non-native to the islands. After the decline of the Bald Eagle this
changed and it upset the functioning of the ecosystem. I read on the National
Park Service site about the habitat that these fox prefer and a little more
about their ecology. I discovered that they prefer shrubby areas which is
fairly native to the Channel Islands (NPS). It turns out that non-native
grazers greatly reduced the amount of these shrubby areas leaving the fox with
little cover. I was also interested to find that these fox due to their Island
biogeography hunted in daylight due to the fact that they had no natural
predators (NPS). This led to them having no defense to predation by Golden
Eagles. The main threat to their existence is still Golden Eagles but the
recovery plan has taken action to limit losses due to this.
Description
of Recovery Plan:
The
recovery plan for the Santa Rosa Island Fox and other three subspecies
protected under the recovery plan can be found on the FWS site. The ultimate
goal of a recovery plan for any species is so the it can ultimately be
de-listed or at a minimum down listed to threatened. While reading the plan for
my species I noted the two key objectives or criterion it had that would make
the plan be successful. The ESA objectives are, “1. To increase population
levels & demographic rates to levels that are self -sustaining. 2. Reducing
or eliminating current threats.” By meeting these objectives they would be
meeting the goal of their recovery plan. They implemented a variety of
different methods in order to meet these objectives. The main one was to
relocate golden eagles away from the Island and to reintroduce bald eagles
back. I also learned in class that they implemented
a few successful captive breeding programs. Although they are still listed
their population levels have risen steadily. According to the FWS the cost of
this has been estimated at $7,615,500.00
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