Pacific Fisher 1
Reintroduction and Restoration of the Pacific Fisher (Martes pennanti) and its Habitat
By
Jordan Bakken
WSU Restoration Ecology
Predator Reintroduction Final Assignment
Dr. Rodney Saylor
5/6/2014
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Introduction
Over recent decades predation has become a high priority interest for ecology and
biology majors around the world due to the inevitable catastrophic changes landmasses
encounter when the balance of predator and prey relationships are warped. The knowledge of
interactions between the species of animals in the world that are on top of the food chain
compared to the animals that dwell below their dominance shows the specific impacts that can
potentially erupt form drastically removing a predator from an ecosystem causing impacts to
the land and social lively hood of the human race. A perfect example of this issue is the
termination of grey wolves in the Pacific Northwest, proposed by farmers and local patrons due
to the negative interaction between the wolves and their livestock led to a simple solution of
killing any wolf found in the farming perimeter. The reduction in over 85% of this predator’s
population led to the exponential growth of elk populations which naturally caused overgrazing
of new sprouts and seedlings of future generations of tree growth. Reintroducing larger grey
wolf populations naturally led to reduction in elk populations which allowed for a larger surface
area of land that is not grazed to the ground.
Predation also demonstrates its significance in other
ways with the interaction of much smaller animals.
One of these animals is the Pacific Fisher, one of the
few only predators that is known to prey on animals
Figure 1 Pacific Fisher (Martes pennanti)
that are not only bigger than them, but also more
dangerous like a small fox or a large porcupine.
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The fisher prefers to nest in higher coastal elevations where large hardwood trees grow
in abundance. When fishers are sighted, their habitats include similar variables of very dense
lower vegetative growth with large old conifer tree growth. They have been sighted from
Northwestern California all the way north into the providences of Canada. They also inhabit
landlocked states such as Idaho and Montana indicating that they potentially could inhabit any
forest environment as long as it includes old growth for shelter and reproduction as well as
plenty of ground vegetation which inhabits an abundance of prey for the fishers [Klug, Richard].
Recent discoveries indicate that the fisher has a very low reproduction rate which inevitably
causes low genetic diversity and a low survival rate. Because of low diversity and reproduction
rates, restoration efforts from groups such as Yosemite National Park Services and Federal Fish
and Wildlife have been established and designated to ensure the survival of this species and
prevent at all costs any chance of extinction. This small weasel-like animal is very rarely seen
from researchers, hikers and spectators alike which indicates lower population levels because if
indications of healthy population levels would show more interactions and encounters of
people. The fisher is an active predator, covering several acres of land daily in search of meals
consisting of a wide range of organisms from truffles and roots deep in the ground to small
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birds and porcupines [United States National Park Service]. This small predator is known for
having several similar traits of a group of predators known as “keystone” species.
Rebuilding a Destroyed Population
The fisher experienced its most catastrophic population drops from excessive hunting by
fur trappers in the 1800’s-1900’s, during the time were soft silky furs that naturally insulates
heat was high in value and demand. It was not until the 1940’s that Pacific Fisher population
decline was noticed, thus implementing a ban on any trapping or killing of the small predator
[Center for Biological Diversity]. This instant reduction in the species population consequently
left the remaining fishers with a lot of hurdles to conquer, hurdles such as rebalancing the gene
flow of the population and finding inhabitable forest land that has the necessary variables to
ensure healthy reproduction rates. Because of the recent motion of attention between state
agencies and the United States federal government directing towards species that are
experiencing issues of low reproduction rates, the U.S. has designed the Endangered Species
Act of 1973 which ensures efforts will be taken into any animal that is faced with potential
extinction. These efforts are focused on the animals with precious skins and furs that were
hunted down and killed in mass populations form the early American settlers.
Now that hunting has been ban for humans against the fisher, the populations now have
a chance to attempt to grow again of course with the help from humans. There is some
controversy going on whether or not the pacific fisher should be on the Endangered Species Act
between the Western states as well as the federal government. Over 15 collaborative groups
including the Center for Biological Diversity (CBD) has petitioned the for the fisher to be scribed
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on the federal Endangered Species Act (ESA), but after several years of consideration and
discussion, the federal services deemed the animal as “warranted but precluded” causing the
candidates to file a suit against the U.S. Fish and Wildlife Service. Unfortunately the momentum
shifted against the CBD as the state of California also agreed to neglect the pacific fisher from
their states list of endangered species in 2010. Later in 2012, a supreme court in the state of
California reconsidered implementing the fisher on their ESA and incorporated an additional
756 of other plant and animal species that were preciously overseen by the U.S. government
and drafted proposals stating that these species need all the help they can get from the state
and federal agencies [Center for Biological Diversity].
Another issue that the fisher faces in the modern world is finding enough habitable land
that is suitable for stable reproduction. Drastic expanding human populations has led to an
overall takeover of land which has been influenced by the propel of human growth and
development with the clear cutting of forests for timber to build housing and the degradation
of fertile top soils to grow an abundance of cash crops with synthetic nitrogen fertilization. The
clearing and fragmentation of old
growth forests has influenced the
declining fisher populations
greatly as they require large trees
to nest in as well as to escape from
larger predators. Leaving large
trees and clearing ground
vegetation does no good to help
Figure 2 Pacific Fisher with a captured grey squirrel
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prevent population decline as the fisher finds many food sources and prey in the ground
vegetation.
Like a cat, fishers are extremely complex hunters as they are very quiet, patient and can
out maneuver quicker animals like squirrels and mice. When it hunts for a meaty meal, the
fisher prefers to have surrounding vegetation for protection as well as an obstacle to attack
prey. Like several other land predators, although raw meat is the preference for food the
fisher’s diet also consists of other types of edible materials old forest growth provides.
Vegetative growth provides the predator with certain berries and fruits that are utilized when
certain prey are not available [“carnivore”]. Their primary diet typically consists of small rodents
like mice, hares, birds and juvenile foxes. Even though their name consists of the term “fisher”,
they actually do not hunt for fish most likely for their desire to keep their lush fur dry and
warm. Old Douglas fir trees in Pacific Northwest forests are valued by timber industries for their
large size and width as trees grow indeterminately therefore can get as big as their
environment will allow them. Thus older trees are able to produce much more timber for
building and are the preferred tree to mass harvest. The common Douglas fir tree is measured
with an average diameter of anywhere from 3-6ft. with an approximate height of 150-250ft.
These large tree canopies help protect the inner wildlife from the harsh winter snow blankets
during the winter season and also helps to provide some insulation of heat by breaking the
changing wind patterns. When large fir trees die off naturally and the tree body is left to
decompose naturally, it provides shelter for an abundance of woodland organisms including the
pacific fisher which uses snags as dens to shelter their adolescent offspring.
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Importance of Old-Growth Forests
According to the U.S. Forest Service (USFS) old growth forests are currently challenged
with four primary concerns; 1) Fire Management from naturally occurring wildfires as well as
controlled prescribed burns. Fire is a natural part of the ecosystem and is inevitable in any are
where human development has occurred. High efforts have been taken into effect with the
designation of volunteer firefighters with tools and skills necessary to fight high intensity fires
that potentially were caused by people. These teams also spend efforts during certain months
of the year to designate controlled burns within forests to reduce vegetative density which
prevents future high intensity wild fires. These prescribed burns have not been perfected to this
day but are still used to strategically conquer any chance the forest has of being burned to the
ground. 2) Development of old-growth characteristics in newly planted/growing forests. In
certain parcels of land where designated timber harvesting is permitted, attempts to keep the
forest on a growing cycle by planting young saplings and juvenile trees is implemented. This not
only keeps the production of timber on track, but it also provides local wildlife with a little
resilience as they have a place to escape to when the trees are old enough for harvest. The
issue with planting trees is that trees do not grow strategically naturally. They grow where
elements are suitable for them to grow unlike timber forests where trees are planted in rows
and columns to maximize the space to yield ratio which naturally reduces any chance for other
species of vegetation to grow; 3) Landscape alterations and modifications from human
association. Humans are considered to be the primary keystone species of the earth as we not
only have an overabundance in our population, but our presence directly affects every
organism on the face of the planet. We have a social responsibility to designate specific areas of
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land to grow and live naturally without any direct human influence to get in the way; 4) Policies
protecting current old-growth forests as well as protections of future forests. Now that we have
identified the importance of these old-growth forests, we must influence our highest ranking
officials to help back up any attempts to protect and maintain originating forests and
ecosystems [“Science Update”]. The protection of old forest growth by designation
conservation parcels and wildlife refuges is the only change the fisher population has as having
a thriving population once again.
The pacific fisher has been overseen by so many people because it has only been seen
by so few. This beautiful predator has hope for a thriving population again with the combining
efforts of saving the old-forest growth for a habitable environment as well as providing support
to the remaining wild fisher individuals that are tagged and recorded today. The importance of
educating the public about the lack of presence of this creature has yet to take off inevitably
preventing the knowledge of the pressures the pacific fissure has to endure because of the
arrival of human settlement in the America. With enough backing and supporting evidence
indicating that this creature is in fact making its greatest attempt to re-spawn its diminished
population, there should be effort on the people’s part to inform others of how they can help
the fisher.
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References:
Center for Biological Diversity. "Fisher." Fisher. N.p., n.d. Web. 3 Apr. 2014.
<http://www.biologicaldiversity.org/species/mammals/fisher/index.html>.
Klug, Richard . "Occurrence of Pacific Fisher (Martes pennanti pacifica) in the Redwood
Zone of Northern California and the Habitat Attributes Associated with their Detection." A
Thesis Presented to The Faculty of Humboldt State University 1 (1997): n. pag. U.S.Forest
Wildlife Services. Web. 1 Apr. 2014.
"Science Update." PNW Research Station 1.4 (2003): n. pag. Pacific Northwest Research
Station. Web. 15 Mar. 2014.
United States. National Park Service. "Pacific Fishers." National Parks Service. U.S.
Department of the Interior, 19 Mar. 2014. Web. 3 Apr. 2014.
<http://www.nps.gov/yose/naturescience/fishers.htm>.
"Carnivore." - National Geographic Education. N.p., n.d. Web. 3 Apr. 2014.
<http://education.nationalgeographic.com/education/encyclopedia/carnivore/?ar_a=1>.