Sierra Nevada Bighorn Sheep - Stephanie Smith

Sierra Nevada Bighorn Sheep

Ovis canadensis sierrae

The wild sheep ranks highest among the animal mountaineers of the Sierra. Possessed of keen sight and scent, and strong limbs, he dwells secure amid the loftiest summits, leaping unscathed from crag to crag, up and down the fronts of giddy precipices, crossing foaming torrents and slopes of frozen snow, exposed to the wildest storms, yet maintaining a brave, warm life, and developing from generation to generation in perfect strength and beauty.

— John Muir, 1894

 

Characteristics

Sierra Nevada Bighorn Sheep are typically 5 feet long and 2 ½ to 3 ¼ feet tall. Males, called rams, can weigh up to 220 lbs, and females, called ewes, can be up to 155 lbs. Rams have an average life span from 10 to 12 years, while ewes live anywhere from 12 to 20 years. The oldest ewe recorded lived to be 17 years old.

Both males and females have horns that continue to grow throughout their lifespan. Males have a large dominant display, while females have less prominant horns. One main difference between the Sierra bighorns and other species such as the Desert bighorns are the shape and curl of the horns. In comparison, the Sierra bighorns have more narrow horns that diverge more widely.

Fur color can range from dark brown to white, depending on the location and time of the year. Molting occurs in the late spring and afterwards results in a darker color. During winter, exposure to the sun reflecting off of winter slopes causes the fur to lighten considerably. 

The body is developed for climbing steep enbankments and scrambling across rocky slopes. The legs are short and stocky, and the rump and shoulders are highly muscular to enable success in this type of environment.

Geographic Range 

The Sierra Nevada Bighorn sheep live exclusively in the Sierra Nevada mountain range of California.

There are three species of Bighorn sheep in California.

Sierra Nevada Bighorn sheep herd locations.

 

Ecology

Ideal habitat is within alpine meadows or summit plateaus fed by springs, and surrounded by steep and rocky terrain. The open meadows provide ample grazing opportunities while the steep topography provides a quick escape from predators. The sheep favor open areas over heavy forest cover as they rely predominantly on their eyesight for predator detection. Limited seasonal migration allows sheep to overwinter at lower elevations where more vegetation is available for feeding. The bighorn sheep are herbivores, feeding primarily on grasses, herbacious plants, and shrubs, selectively favoring new growth.

Males establish a dominance hierarchy prior to the mating season. Dominance is established through visual displays, neck wrestling, kicking, and horn clashes. The most dominant males typically have the largest bodies and horns. 

Male horn display.

Population

Prior to European settlement, Bighorn sheep populations were estimated to be around 1,000 individuals at the least. However, unregulated hunting and spread of respiratory diseases from domestic animals decimated that number. In 1995 barely 100 individuals were counted in the Sierra Nevada range.

Listing Status

The Sierra Nevada Bighorn sheep was listed as an endangered species on January 3rd, 2000, under the Endangered Species Act. The species was given emergency listing in 1999 when there were only about 100 individuals in existence, and was formally added to the endangered species list the following year. It is currently still listed as an endangered species, although the recovery and population of the species is having major successes. In 2016, the population was estimated to be over 600 individuals.

Recovery

The most important actions needed in recovery for the sheep:

-Protect existing herds by maximizing population growth and managing predation.

-Augment small herds through translocation. Larger herb numbers can boost population more effectively and can better resist predators.

-Prevent contact between Sierra Nevada Bighorn Sheep and local domesticated sheep and goats to limit potential spread of disease.

-Reintroduce bighorn sheep to vacant herd units.

-Monitor genetic variation to ensure there is genetic variation and reduce inbreeding.

Females have a long life span and have above a 90% survival rate. Males are slightly lower, but also have near 90% survival rate. Lambs have a rate of 50% on average, which varies greatly. Lambs have a lower survival rate due to variable weather patterns and predation.

Lambs on a steep cliff.

Threats

The main threats to the population are diseases spread from domestic animals (sheep and goats), predation, low genetic diversity caused by inbreeding, and small population size in general (caused by varying natural factors such as unpredictable weather and other natural events). Extinction threatens the sheep populations if the main threats to survival are not properly managed or reversed.

What can you do?

Tracking devices have been fitted to many individual sheep in order to monitor and learn about behavior. Hikers and backpackers are encouraged to report any sightings in order to provide more information for scientists to work from. If you encounter a sheep, be careful not to disturb or spook it. Any negative disturbances can affect their fitness and survival.

Other resources?

More information can be found at the following sources:

  - http://www.dfg.ca.gov/snbs/SheepFacts.html

- http://sierrabighorn.org/ 

- https://www.yosemiteconservancy.org/wildlife-habitat/protecting-sierra-nevada-bighorn-sheep

 

The Giant Kangaroo Rat - Amanda Stahler

The Giant Kangaroo Rat

“Humanity can no longer stand by in silence while our wildlife are being used, abused and exploited. It is time we all stand together, to be the voice of the voiceless before it's too late. Extinction means forever.” 

― Paul Oxton

Founder of Wild Heart Wildlife Foundation

Description and Ecology

The Giant Kangaroo Rat 
(Photo By John Roser. ARKIVE,http://www.arkive.org/giant-kangaroo-rat/dipodomys-ingens/ )

The Giant Kangaroo Rat, also known as Dipodomys Ingens, is a heteromyid rodent endemic to California. The Giant Kangaroo Rat is not only an endangered species, but is also a keystone species, playing a vital part in its ecosystem. Even though it is the largest of its species, this adorably small rodent is barely 150 grams. They use bipedal locomotion, which is two-footed hopping, jumping around on its large hind limbs with a short neck and flat large head. If that isn’t cute enough, they also have a small tuft of long hairs on the end of their tails and have large fur-lined cheek pouches. (Davison)

The Giant Kangaroo Rat’s diet is primarily seed based, but also contains green plants and insects. They have an intricate burrowing system, where they first gather individual seeds scattered over the ground surface, fill their cheek pouches with the harvest seeds, and then finally place the seeds in little pits. They then cover th epits with the seeds with a loose layer of dirt to let them dry. They have the ability to transport large quantities of food in their cheek pouches, especially lactating females. They harvest for food from sunset to near sunrise, but they are most active the first two hours after dark. Their highly developed harvesting behaviors and the relatively high longevity of adults with established burrow systems allows them to endure severe droughts. (U.S. Fish and Wildlife Service). Even though they are extremely cute and have very unique and effective harvesting skills they still face many threats.

Geographic Location and Population Changes

Extant Distribution of the Giant Kangaroo Rat
 (Endangered Species Recovery Program, U.S. Fish and Wildlife Service,http://esrp.csustan.edu/publications/pubhtml.php?doc=sjvrp&file=chapter02H00.html)

The Giant Kangaroo Rat’s habitat has greatly been reduced, especially compared to their historical distribution. Before the 1950’s their habitat was estimated to spread over 1.5 million acres across the Western San Joaquin Valley, Carrizo Plain, and Cuyama Valley. Currently their populations have been greatly fragmented into different geographical units due to barriers such as steep terrain, agricultural land, industries, and urban land use that offer unsuitable or no habitat options for the rat (U.S. Fish and Wildlife Service).

Their extant habitat is estimated to be 27,540 acres, about 2 percent of historical habitat. The units are now located in the southern San Joaquin Valley are the Kettleman Hills in Kings County's and Lokern, Elk Hills, and other uplands around McKittrick, Taft, and Maricopa in Western Kern County. Changes in their population density generally coincide with amount of rainfall and herbaceous plants (Davison). Since their habit has been reduced by nearly 98%, the Giant Kangaroo Rat has been put on the endangered species list.

Endangered Listing Date and Type

The Giant Kangaroo Rat was officially declared endangered by the Endangered Species Act in 1980, then by the California Endangered Species Act in 1987, and finally by the IUCN (International Union for the Conservation of Nature) Red List in 2008. Their recovery plan was established on September 30, 1998 for the California and Nevada region. They are listed as an E species, endangered, and are currently in the plan stage F, which means the final plan is approved by the Regional Director. (U.S. Fish and Wildlife Service)

Cause of Endangerment and Main Threats

The Giant Kangaroo Rat faces threats from Industrial Exploitation (https://www.konicaminolta.com/kids/endangered_animals/library/field/giant-kangaroo-rat.html)

The Giant Kangaroo Rat is threatened by agricultural and urban development, rodenticides, and oil drilling and exploration. The primary cause of their habitat loss is from the agricultural development in the San Joaquin Valley and the death of many Giant kangaroo Rats is due to rodenticides used to control ground squirrels (U.S. Fish and Wildlife Service. The sale of Naval Petroleum Reserve number in Elk Hills to private interests could represent a threat to one of largest regional populations of the Giant Kangaroo Rat, because that could result in the increase in the rates of exploitation (U.S. Fish and Wildlife Service). Urban and industrial Development, petroleum and mineral extraction, new energy and water conveyance facilities, construction, and transportation infrastructures are also destroying the habitats for the Giant Kangaroo Rats and increase the threats to the species by reducing and further fragmenting populations. (Davison).

San Joaquin Kit Fox preys on the Giant Kangaroo Rat
 (http://pixdaus.com/gotcha-fox-and-kangaroo-rat-nature-wildlife/items/view/78175/)

The Giant Kangaroo Rat is a critical part of the ecosystem for the areas they inhabit and their existence is crucial to the existence of other endangered species. The Giant Kangaroo Rat is the keystone species of the Carrizo Plain, serving as the foundation for the entire ecosystem. Their survival is critical to the existence of multiple species such as the San Joaquin kit fox, the blunt-nosed leopard lizard, and the San Joaquin antelope squirrel. They are the main diet for the San Joaquin kit fox and their burrows provide shelter for the squirrels and lizards. 

Wildflowers in bloom in the Carrizo Plains National Monument 
(https://calcoastnews.com/2017/08/carrizo-plain-national-monuments-fate-still-unknown/)

In the Carrizo plain Natural Area, which is threatened by the review by the Trump Administration by the Secretary of Interiors Ryan Zinke, is the home to the endangered California Jewelflower ,whose growth depends on the soil conditions made from the burrowing system of the rat (“Giant Kangaroo Rat.” Los Padres ForestWatch). Though there are many population-monitoring plots of land that were set in place since 1995, they are no longer receiving funding for proper monitoring and management. (U.S. Fish and Wildlife Service).

Recovery Plan

The Giant Kangaroo Rat needs your help! (http://drakehs.org/academics/seadisc/endangeredspecies/2008/Giant%20Kangaroo%20Rat/wEBPAGE2.htm)

Substantial progress has been made in terms of research and habitat protection, however a specific recovery plan for the Giant Kangaroo Rat is still needed for their survival. Certain organizations have taken steps to help with their protection such as the US Department of Energy Naval Petroleum Reserves in California, which is now publicly owned. This will help to ensure that Giant Kangaroo Rat’s habitat will be protected during and after extraction of petroleum deposits and won’t be harmfully exploited by large oil corporations. The state of California US government has acquired private property in the Carrizo Plain natural area, which will help to reduce threats to the species from cultivation and illegal use of rodenticide. (U.S. Fish and Wildlife Service).

Three major steps towards the recovery of the Giant Kangaroo Rat:

1.       The number one priority is habitat protection through proper land use and management. This starts by making land publicly owned and conserved in the Carrizo Plain national area, Naval petroleum reserves in California, Lokern Natural Area in Sierraville Panoche Natural Area. Land that is already in public and conservation ownership should also be maintained properly.
2.      Increasing research on habitat management and restoration, focusing on effects of livestock grazing on habitat quality and habitat restoration on retired farmland, especially abandoned dry land farms
3.      Continuing to protect land supporting key populations. Examples of some of these areas include the Lockern area, Naval Petroleum Reserves, Western Fresno and Eastern San Benito counties, the strip along the West of Interstate Highway 5, Western Kern County,  Cuyama Valley,  Kettleman Hills, and San Juan Creek Valley in San Luis Obispo.

In order to ensure these steps towards recovery there needs to be a long-term program to periodically monitor their populations. Monitoring should be conducted annually for at least a 10-year period and periodically after at five-year intervals. (U.S. Fish and Wildlife Service).

What can you do?

Learn about how our government is treating our national monuments and how they pose a threat to endangered species like the Giant Kangaroo Rat. Our government should be protecting our nation and not destroying it. If you agree and think the Giant Kangaroo Rat should be protected through protecting the Carrizo Plains National Monument express your concerns to our government and the Secretary of interior is Ryan Zinke.

Secretary of Interiors Ryan Zinke

Department of the Interior

1849 C Street, N.W.

Washington DC 20240

Other Resources

Stay Updated about threats to the Giant Kangaroo Rat in San Luis Obispo:

•     Carrizo Plains National Monument Threatened                                 
•    The article above states that local politicians are encouraging the community to write to Ryan Zinke

Learn More about the Giant Kangaroo Rat:                 

• California Bureau of Land Management
• Smithsonian National Museum of Natural History

Glossary

• Heteromyid rodent: is a family of rodents consisting of kangaroo rats, kangaroo mice, pocket mice and spiny pocket mice
• Endemic: a plant or animal native or restricted to a certain country or area
• Endangered species: is a species which has been categorized as very likely to become extinct
• Keystone Specie: are species that play a disproportionately large role in the prevalence and population levels of other species within their ecosystem or community.
• Bipedal locomotion: is a form of terrestrial locomotion where an organism moves by means of its two rear limbs or legs.
• High longevity: long life expectancy
• Historical distribution: original location where the species was distributed
• Extant habitat: existing habitat
• Population fragmentation: is a form of population segregation. It is often caused by habitat fragmentation
• Habitat exploitation: the action of making use of and benefiting from the resources of a specie’s habitat
• Dry land farms: crops that needed little rainfall
• Rodenticides: a poison used to kill rodents

Sources

1.      Davison, veronica_davison@fws.gov, External Affairs Divison, Sacramento Fish & Wildlife Office, Veronica. “Giant Kangaroo Rat - Mammals, Endangered Species Accounts | Sacramento Fish & Wildlife Office.” Sacramento Fish and Wildlife, www.fws.gov/sacramento/es_species/Accounts/Mammals/giant_kangaroo_rat/.
2.      “Giant Kangaroo Rat.” Los Padres ForestWatch, 2 Feb. 2018, lpfw.org/our-region/wildlife/kangaroo-rat/.
3.      U.S. Fish and Wildlife Service. 1998. Recovery plan for upland species of the San Joaquin Valley, California . Region 1, Portland, OR. 319 pp.

Author: Amanda Stahler | Student, California Polytechnic State University  

Published: March 5th, 2018

Mexican Grey Wolf - Colin Scharff

The Mexican Grey Wolf

Who is this Good Pup?

The Mexican Grey Wolf, or Canis lupus baileyi, is a subspecies of the well-known Grey Wolf. According to the US Fish and Wildlife Service, Mexican wolves typically weigh 50 - 80 pounds and measure about 5 ½ feet from nose to tail, and stand 28 to 32 inches at the shoulder. They have a distinctive, richly colored coat of buff, gray, rust, and black, often with distinguishing facial patterns; solid black or white variations do not exist as with other North American gray wolves. Their genetic distinction and unique range make them a target for conservation, in the hopes of preserving biodiversity. (United States, Fish and Wildlife Service)

Where is Home for Them?

When the Grey Wolf reached its conservation goals in places like Yellowstone National Park, attention was turned to the Mexican Grey Wolf. This wolf is the most distinct and southern sub-species of Grey Wolves in North America, and has a complex history of protection over the past years. These wolves range crosses the US/Mexico border, with ranges in New Mexico, Arizona, and Northern Mexico. This range makes it so this recovery effort is an international one, with proposed populations in Mexico and the US, with the possibility of co-mingling over time. The wolves live in the forested mountain ranges that exist along the border, providing the best prey options, and cover from the elements. (United States, Fish and Wildlife Service)

What Seems to be the Problem?

The Mexican wolf was in dire straights. The wolf population was down to the low tens, and only by captive breeding was the species saved from extinction. These wolves, like their northern cousins, were targeted by ranchers for their predation on livestock, like cattle and sheep. That, combined with the increasingly small habitat available to them in the southern forests of the US and northern Mexico, made the population shrink rapidly. This shrunken population started inbreeding and suffered genetic ailments, as their diversity decreased. The wolves that are being introduced in the wild now are decedents from only seven individuals from the original captive breeding programs. (United States, Fish and Wildlife Service)

What is Being Done?

As the state of the Mexican wolf declined, the species was listed as Endangered in 1978, but due to lawsuits and gridlock, didn't have anything happen much until 1998. This is when the first pack of Mexican wolves was released in the Southern US wilds. A group was introduced back into Mexico in 2011. The recovery plan created in 1982 was revised in 2017 to reorder the conservation effort, and a new plan is being enacted. This plan is far more complete, and hopes to down-listing the Mexican wolf after one of two options are achieved. As quoted from the 2017 recovery plan, the two options relate mostly on either one larger healthy population in the US only, or two smaller healthy populations, one in the US, one in Mexico. The specifics are quoted below.

Option 1: The Mexican wolf will be considered for down-listing when:

a) The United States population average over a 4-year period is greater than or equal to 320 Mexican wolves; and

b) Gene diversity available from the captive population has been incorporated in the United States population through the scheduled releases of wolves surviving to breeding age as identified in de-listing criteria.

Option 2: The Mexican wolf will be considered for down-listing when a minimum of two populations (one in the United States and one in Mexico) meet abundance and genetic criteria as follows:

a) Each population average over the same 4-year period is greater than or equal to 150 wolves with an annual positive population growth rate; and

b) Gene diversity available from the captive population has been incorporated into both the United States and Mexico populations through the scheduled releases of wolves surviving to breeding age as identified in de-listing criteria.

These are the ultimate goals of the recovery plan, and either would be enough to have the Mexican wolf ranked as threatened, instead of endangered. As of 2016, there are an estimated 113 wolves in the United States, and 31 in Mexico. To deal with the problems regarding limited habitat there will be more law enforcement of protected areas, especially in Mexico. The protection of the land will revolve around making possible pathways between the high quality habitats and possible habitat, so the possibility of inter-mingling is maintained. The genetic diversity will be further maintained by introducing captive individuals and groups into the populations to stave off genetic drift. (United States, Fish and Wildlife Service) With all these programs working effectively over the next few years, the Mexican wolf can be saved.

As stated in the recovery plan, "Our recovery strategy, which is based on the current status of the Mexican wolf in the wild and the threats it faces, is to establish and maintain a minimum of two resilient, genetically diverse Mexican wolf populations distributed across ecologically and geographically diverse areas in the subspecies’ range in the United States and Mexico." (United States, Fish and Wildlife Service) The programs have been successful so far, and many people in the effort are optimistic. Workers are continuing to monitor the new pups, vaccinate them, and make sure the genetics are stable, and will continue to do so, until the population is secure. (Arizona Game and Fish)

What Can You Do?

One of the main things that can be done to help the Mexican wolf is spread awareness about these creatures online, and help combat the rhetoric of ranchers that want them removed, stating a threat to their livestock. The wolves are being trained to not eat livestock, as seen in the video below. The ranchers are misinformed about the danger, and see wolves as an existential threat to their livelihood. (New Mexico Cattle Grower's Association) There are less than 150 wolves in the US and they are not going to hunt the cows to the point of financial ruin. A species is worth the cost, and the program can pay them, like in many other conservation programs. The second biggest thing people can do to help the Mexican wolf is protest the construction of a potential border wall along the US/Mexico border. The wall would make it impossible for the wolves to co-mingle across the border, as has already happened twice now. The fence does not keep them out, but a wall might, hurting their genetic diversity even more.

Listen to Them, not Me!

My hometown of San Diego is rearing wolves for the effort, and give a brief overview of how they are trained to avoid livestock, as well as their general goals. If you want to see these creatures move, play and howl, watch below! (Mexican Gray Wolves Making a Comeback)

Citations:

“A Growing Population of Mexican Wolves.” Arizona Game and Fish, 30 Mar. 2015, www.youtube.com/watch?v=IfMg24z1lsY.

“Mexican Gray Wolves Making a Comeback.” KPBS News, 7 Nov. 2011, www.youtube.com/watch?v=bSkV2e8RJgw&t=6s.

“New Mexico Ranchers Fight to Stay Alive with Mexican Gray Wolf.” New Mexico Cattle Grower's Association, 2014, www.youtube.com/watch?v=l_4g-rB2UXk&t=55s.

United States, Fish and Wildlife Service, Southwest Region. “Mexican Wolf Recovery Plan.” Mexican Wolf Recovery Plan, vol. 1, pp. 1–50.

“What Is a Mexican Wolf?” Official Web Page of the U S Fish and Wildlife Service, US Fish and Wildlife Service, www.fws.gov/southwest/es/mexicanwolf/natural_history.cfm.