The endangered species found in Yosemite National Park that I research was the Sierra Nevada big horn sheep, (Ovis Canadensis sierra). This animal is classified as federally/state endangered by the United States and the California government. This particular animal was the only one on Yosemite’s wildlife species list that had this title, which is the most concerning out of the five titles given to species: federally endangered, federal candidate, state endangered, state threatened, and California species concern.
There are multiple threats to the Sierra Nevada big horn sheep including diseases spread throughout herds, low quality vegetation, and inbreeding leading to low genetic variability (which create few adaptations). Goals made by the California department of fish and wildlife is to have a group of 300+ female sheep breed with 4 different groups of male sheep, all different phenotypically.
The latest population estimate was in 2010 of about 400 sheep, but the number is increasing rather than decreasing.
There are multiple threats to the Sierra Nevada big horn sheep including diseases spread throughout herds, low quality vegetation, and inbreeding leading to low genetic variability (which create few adaptations). Goals made by the California department of fish and wildlife is to have a group of 300+ female sheep breed with 4 different groups of male sheep, all different phenotypically.
The latest population estimate was in 2010 of about 400 sheep, but the number is increasing rather than decreasing.
The definition of a keystone species is a species that is found somewhere in the middle of a certain food chain that would affect the entire chain and result in reduced biodiversity. In Yosemite National Park a keystone species would be considered the mountain lion. Being a tertiary consumer and predator to many animals makes it a keystone species for the fact that the population of its prey would grow out of control without its presence. Examples of animals mountain lions eat are small to medium sized mammals such as squirrels, sheep, raccoons, chipmunks and more.
Many of the mountain lions’ prey are either secondary or primary consumers meaning they prey upon smaller consumers or producers. This makes mountain lions a keystone. Without these animals in the food chain, because of the removal of the mountain lions, devastation would occur.
For example mountain lions eat California Ground Squirrels, which eat berries located throughout the park and the temperate forest. If mountain lions were removed from this chain the population of squirrels would increase, therefore eating more berries and causing the source of berries to go down throughout the park depleting a natural producer. Without food for the vast amount of squirrels located in the park, they will have to resort to an alternate food source that may or may not be healthy for them.
Each step of the cycle leads to the next in a cause-and-effect relationship. Luckily for Yosemite National Park and all those visiting it, the mountain lion is in no danger of going endangered in the Sierra Nevada area.
Many of the mountain lions’ prey are either secondary or primary consumers meaning they prey upon smaller consumers or producers. This makes mountain lions a keystone. Without these animals in the food chain, because of the removal of the mountain lions, devastation would occur.
For example mountain lions eat California Ground Squirrels, which eat berries located throughout the park and the temperate forest. If mountain lions were removed from this chain the population of squirrels would increase, therefore eating more berries and causing the source of berries to go down throughout the park depleting a natural producer. Without food for the vast amount of squirrels located in the park, they will have to resort to an alternate food source that may or may not be healthy for them.
Each step of the cycle leads to the next in a cause-and-effect relationship. Luckily for Yosemite National Park and all those visiting it, the mountain lion is in no danger of going endangered in the Sierra Nevada area.
Mountain lions found in Yosemite affect a depleting Sierra Nevada big horn sheep in two ways: preying on them, and forcing big horns to move out of their natural habitat to an area with more severe conditions. Big horn sheep are normally found around an elevation of 10,00 feet in the park, the same elevation as mountain lions, but as mountain lions started to prey on the sheep more and more, the sheep moved to higher elevations where many sheep could not withstand the colder temperatures and weather. The number or Sierra Nevada big horn sheep was not an impressive one to start but the threat of mountain lions affects the population to even smaller numbers. It is obvious that mountain lions affect the Sierra Nevada big horn sheep population, but the lack of big horn sheep does not affect the mountains too much. Because mountain lions prey on more than just big horn sheep, (such as raccoons and coyotes) their population is not in any threat. In other words Sierra Nevada big horn sheep do not affect mountain lion population because mountain lions do not experience a lack of food.
Fishers found in Yosemite are vitally important to the ecosystem found within the park. Fishers, a member of the weasel family, are medium sized mammals that prey on fungi, fruit, birds, and small mammals. They are endangered because of migration from natural habitat (Oregon/Northern California or Southern Sierra Nevada), predation from larger animals, disease, and wildly enough being hit by cars. As Steve Thompson, Chief of Wildlife Management for Yosemite put it, “Anytime you lose a species from an ecosystem it’s a tragedy.” Fishers, being highly endangered, pose a threat to Yosemite’s deciduous temperature forest biome, as it is a primary consumer that preys on smaller consumers and producers, but also acts as prey for secondary consumers.