Pacific Pocket Mouse

Pacific Pocket Mouse

(Perognathus longimembris pacificus)

By: Adam Roge

(http://www.zooborns.com/.a/6a010535647bf3970b019aff3ab053970b-800wi)

Description & Ecology

The Pacific Pocket mouse is a subspecies of the "little pocket mouse" species, which is a part of the rodent family. The mouse is covered in brown silky fur, and lives in sandy coastal areas. Weighing as little as .25 oz, this small mouse is endemic to the coast of southern California. Historically, the population of these mice ranged from Los Angeles down to San Diego county, and have not been recorded farther than 2.5 miles away from the ocean. The Pacific Pocket mouse is nocturnal, and mainly eats small insects and seeds, which they burrow for when it's dark out to avoid the sun. The pocket mouse then saves these seeds in their burrow for when they hibernate during the winter. The Pacific Pocket mouse's name is due to its external "pockets" in its cheeks, which are used to temporarily store these seeds. Besides finding a mate, the Pacific Pocket mouse does not engage in direct social interaction with other mice. Female Pacific Pocket mice typically give birth to one litter per year, with each litter containing somewhere between 2-8 babies. The ideal breeding season for the mouse is in the spring, usually sometime between April and June. In captivity, the lifespan of the Pacific Pocket mouse is usually between 4-6 years, however in the wild, the mouse's lifespan is reduced to 3-5 years. The picture below shows the historic localities of the Pacific Pocket mouse, showing both the number recorded in the specific location, as well as the year recorded.

Geographic & Population Changes

The Pacific Pocket mouse was originally thought to have gone extinct, up until 1993, when they were re-discovered after a 20 year period during which the mice were not detected. Currently, these mice are known to exist in three locations in California: Dana Point headlands, Orange County, and San Diego County. The current occupied habitat for the Pacific Pocket Mouse is estimated to be less than 400 hectares (or 1,000 acres) at the three locations combined. The geographic range of the Pacific Pocket mouse has been greatly affected by urban and suburban development along the coast of California, and unfortunately, this development is expected to continue indefinitely. Using the mark and recapture strategy to determine the population of the Pacific Pocket mouse, it is believed that there are about 150 of these mice left in existence shared among the three locations.

Listing Date & Type of Listing

The U.S Fish and Wildlife Service listed the Pacific Pocket mouse as endangered under the Endangered Species Act on September 29th, 1994, after rediscovering a single population at the Dana Point headlands.

Cause of Listing & Main Threats to Continued Existence

The main cause of the Pacific Pocket mouse being listed under the Endangered Species Act, is due to urban and suburban development along the coast of California. Off-road vehicle activities, constructing highways and roads, and urbanization of the coast have all contributed and continue to degrade and fragment habitats within the historic range of the Pacific Pocket mouse. Industrial and agricultural development have also aided in the decline of the species. Currently, the vast majority of the California coast has been developed and urbanized, and the percentage that is still undeveloped is decreasing every year. The picture below shows us how developed the coast of California has become.

(http://stophermosabeachoil.com/the-california-coastal-commission/)

Description of Recovery Plan

The ultimate goal of the recovery plan is to protect and maintain sufficient populations and habitats of the Pacific Pocket mouse, which will allow the U.S Fish and Wildlife Service to de-list the subspecies under the Endangered Species Act. However, the recovery of the mice will involve a two stage process, that begins with re-classifying the subspecies from endangered to threatened status. It is estimated that the recovery of the Pacific Pocket mouse will take approximately 25 years (until the year 2023), and the cost will amount to 7.5 million dollars. The recovery plan was initiated in 1998.

Details of the Recovery Plan

Step number one: Identify all extent populations and essential habitat. As I stated above, the Pacific Pocket mouse currently only lives in three locations of California. Loss or degradation to any of the habitats in these locations will only further increase the probability of the mice going extinct. The plan makes it clear that it is critical to protect and secure the remaining mice populations and habitats. COST = $511,000

Step number two: Prepare and implement habitat management plans. This includes controlling and removing the exotic and invasive plants that grow in the Pacific Pocket mouse's habitat, which threaten the mouse's habitat. This also includes controlling house and feral cats, as these are predators of the Pacific Pocket mouse. Furthermore, vulnerable habitat should be fenced when necessary to ensure the habitat is not disturbed by humans. The management plan depends on the location of the population/habitat, and will be enacted accordingly using the techniques I listed above. Each management plan for each location will be monitored closely to ensure its effectiveness. COST = $2,900,000

Step number three: Enhance and expand the Pacific Pocket mouse habitat. This includes controlling and even manipulating vegetation in selected target sites to enhance their habitat by reducing floral cover. This also includes ensuring that there are adequate seed sources in the habitats, as these seeds are the main source of food for the Pacific Pocket mice. The overall objective of this step is to give the mice an ideal habitat so they can flourish and grow their population. COST = $698,000

Step number four: Conduct research on the life history, ecology, and population biology of the Pacific Pocket mouse. The information that is collected will be used to guide recovery actions and construct mathematical models that can help predict the likelihood of the persistence of the species over time. Understanding how the populations of Pacific Pocket mice live is critical to ensuring the longevity of the species, and to ensure they don't become endangered again. COST = $1,053,000

Step number five: Identify and implement measures to create additional populations. Simply protecting and enhancing all existing mice habitats and populations may not be enough to ensure full recovery. The plan states that it may be necessary to establish a captive breeding population that can later be released into existing or unoccupied habitat. Most current mice populations occur in small and fragmented habitats, however potential unoccupied habitat has been identified on publicly owned land that may be suitable for the Pacific Pocket mouse. The establishment of populations in these unoccupied habitats could help contribute to the species recovery. COST = $2,096,000

Step number six: Enhance public awareness of, and appreciation for, the Pacific Pocket mouse recovery program. This will mainly be done through educational and interpretive programs. Public awareness of recovery efforts will help reduce impacts to protected populations. Interpretive signs and exhibits should be erected near Pacific Pocket mice populations to guide human behavior near the se habitats. COST = $211,000

What can YOU do to help?

The biggest thing you can do to help is to be respectful and careful when entering territory with local Pacific Pocket mice habitats nearby. Don't litter, or drive vehicles on or near habitat sites, as this will further degrade the habitat. Pay attention to instructional signs and follow proper behavior when treading on mice-populated land. You can also help create awareness of species and their recovery status by posting on social media, or creating an article or blog about them, just like I am doing. If you really want to help, and have a couple million dollars to spare, donating money to the U.S Fish and Wildlife service would tremendously help the recovery efforts of the Pacific Pocket mouse.

Lastly, if you would like to help one of the monitoring programs for these mice located in Camp Pendleton, you can contact the principle investigator for this project below, Robert Fisher. A link for further details on this project can be found here --> http://www.werc.usgs.gov/Project.aspx?ProjectID=116

Contact Info:

Robert Fisher

Email: rfisher@usgs.gov

Phone Number: (619) 225-6422

Address: San Diego Field Station

4165 Spruance Road Suite 200

San Diego, CA 92101

(http://cdn.sandiegouniontrib.com/img/photos/2014/12/08/mouse_t837.JPG? 5df2a6e0ac564ff4ddc2702f3c8561935b88c24b)

References

http://ecos.fws.gov/docs/recovery_plan/980928c.pdf

http://www.werc.usgs.gov/Project.aspx?ProjectID=116