Future Prospects for Yosemite

Through continuous preservation, research, and environmental protection, Yosemite National Park should have a bright future as both a vacation destination and a wildlife sanctuary.  Ongoing scientific research is a critical part of this prospect, covering topics such as declining animal species studies, invasive plant removal strategies, and human carrying capacity issues.  Yosemite has a resource management staff of over 100 people and also processes hundreds of research permits each year for its staff and outside interests.  ("Yosemite National Park" 2011) Scientists and wildlife activists take part in keeping track of endangered species sightings, invasive plant and animal species, and the number of visitors that come to the park each year.  Fire management is another way in which Yosemite staff protects the park-- Yosemite's fire management program is designed to protect life and resources, but also to ensure the continuation of fire as a natural process.  Naturally occurring fires allow forests to be thinned, the recycling of nutrients, and the decomposition of dead, woody debris.  If scientists continue to control and observe the occurrence of fire in Yosemite, further ecological problems will be avoided.  Preservation is a final major element of Yosemite's future, and it is through preservation that the park will continue to thrive off of tourism for years to come.  Yosemite archaoelogists have found over 1,500 sites that hold material remnants of past lifeways.  Architects make sure to create any buildings with a rustic design in order to blend the buildings in with their natural surroundings. Excessive vegetation growth has also adversely impacted the park's iconic views and scenic vistas, meadows, and discrete line of sight.  This has compromised the visitor experience and impacted natural and cultural resources in Yosemite.  The National Park Service Organic Act and the Scenic Vista Management Plan are two government-sponsored programs that will prevent this overgrowth from occurring in the future. (Jenkins 2011) 

Ecosystems and Species Yosemite Supports

There are over 400 species of vertebrates, invertebrates, plants, and mammals found in Yosemite National Park.  (Jenkins 2011) The high diversity of species is due to the fact that Yosemite supports habitats ranging from wooded grassland, foothill chaparral, coniferous forests, and alpine rock.  Lush meadows support black bears and mule deer.  The interface between meadow and forest attracts a lot of animals because they can use the meadow for water and food, but use the forest for cover and protection. The park's coniferous forest features a relatively mild climate and a provides a habitat for bobcats, gray foxes, spotted owls, mountain kingsnakes, and a variety of bats.  At higher altitudes, there are fewer wildlife species-- gold-manteled ground squirrel, chickaree, western fence lizard, and alligator lizard call the alpine rocks home.

Assessment of Current Impacts Table

Table created by Madison Beall, based off of information on other posts in this blog.

Current Human Impacts on the Ecosystem

Yosemite National Park receives about 3.5 million visitors a year.  Yosemite supports over 400 species of animals and plants.  (Hutter, 2011) Humans outnumber animals and cause serious threats to Yosemite's wildlife and ecosystems.  Although the park provides high-quality habitats, approximately 40 species have a special status under California endangered species legislation.  ("Yosemite National Park", 2011) Human impacts on the ecosystem include loss of a natural fire regime, air pollution, habitat fragmentation, and climate.  On a more specific and local basis, factors such as the availability of human food and occurrence of road kill can negatively affect wildlife species.  Three species- the grizzly bear, the California red-legged frog, and foothill yellow-legged frog- are believed to be destroyed in the park within recent history. 


The introduction of exotic or non-native species that cause forest pests is also a problem.  Forest pests result when non-native insects and diseases are introduced into an ecosystem and cause environmental damage.  When humans bring firewood from outside the valley into campsites, non-native animal, plant, and disease species can get into the ecosystem.  Agents such as Sudden Oak Death, light brown apple moth, Asian long horned beetle, and Formosan termite are four species scientists are particularly worried about.  Forest pest problems have grown throughout the past 150 years. Non-native insects and diseases not only inflict harm on the species they attack, but also on associated plants and animals in their food chain.  The large number of species affected may become extinct simply because a camper brings in firewood from home.  


Areas of concentrated human use in Yosemite affect wildlife by removing, fragmenting, and degrading habitat, which affects the diversity and abundance of some species in those areas.  These effects are limited to relatively small areas of the park, but a history of 80 years of fire suppression in Yosemite has really affected wildlife habitat over a larger span of area in the park.  Fire is a natural, necessary occurrence because it maintains a healthy mixed habitat in vegetation that provides ecological niches for wildlife. 

Historical State of Ecosystem

Yosemite National Park is located within Yosemite Valley, a glaciated landscape in the Sierra Nevada Mountains.  Rock fall is responsible for creating Yosemite's scenery-- more than six hundred rock falls have occurred in the park during the past 150 years.  (Colten, 2011)  Glaciation has created U-shaped canyons, rounded domes like Half Dome, waterfalls like Bridal Veil Falls and Vernal Falls, and jagged peaks.  Two glaciers still remain at Mount Maclure and Mount Lyell.  Spring floods from river channels redistribute rock, soil, silt, and sand.  The ecosystem lacks water in the summer, and some thirsty plants must go dormant in order to survive.  3% of Yosemite's area is meadows, which act like sponges as they absorb and hold water when snowpack melts.  ("Yosemite National Park", 2011) Meadows contain one third of all plant species found in the park, and a large portion of the park's animals depend on meadow for habitat or food. When Euro-American settlers discovered Yosemite's meadows in the 1850's, they were surrounded by open conifer forests and woodlands.  Conditions changed when pioneers transported cattle and sheep onto Yosemite Valley Meadows and planted non-native species for grazing.  In the 1860's, grazing increased because of droughts in the Central Valley-- during the peak of the wool industry after the decline of the Gold Rush.  Use of these meadows decreased in the 1900s.  American Indians used to burn these meadows, but settlers stopped anthropogenic burning.  Fire might have promoted meadow stability by reducing the encroachment of the surrounding forests, but there is not enough evidence to make this claim for all meadows.  

How Can Human Impacts on Yosemite Improve?

Since humans have caused most of the ecosystem damage that has occurred in Yosemite, there are plenty of things humans can do to improve their impact.

Signs, advertisements, and brochures are found all over the park that encourage little things humans can do to make a big difference.  Being aware is very important- people can avoid transporting unwanted invasive plants and animals, avoid feeding animals human foods, and report sightings of specific animal and plant species to park rangers.

Some Yosemite campgrounds have many campsites with campfires.  Emissions from simultaneous campfires can degrade air quality on a local scale, which is harmful for people and animals.  People should bring lanterns and try to limit the campfires that they start in the late night and early morning hours, when inversions trap and concentrate fine particles from the campfires near the ground, creating local conditions harmful for inhabitants.  

Soundscape is also a very important human impact that should be reduced.  Yosemite National Park takes pride in its quiet nights and early mornings, with an absence of cars, motorcycles, construction noises, and airplanes.  A soundscape is a valuable resource like water or wildlife that can be easily degraded by innapropriate sounds or sound levels by humans.  Animals can get scared away, can get upset and irritated, and often in the past have attacked humans because of the way that visitors threaten wildlife habitat.  People need to lower their voices and reduce the amount of sounds they create while visiting the park for this reason.

A major cause of animal death is due to unsafe driving and roadkill.  Humans need to drive slowly and safely while in the park.  


Source of Image:  http://www.nps.gov/yose/naturescience/soundscape.htm

References

Colten, Craig E.Dilsaver, Lary M. "The Hidden Landscape Of Yosemite National Park." Journal Of Cultural Geography 22.2 (2005): 27. MasterFILE Premier. Web. 18 Nov. 2011.

Hutter, Carollyne. "Keeping Close To Nature's Heart." Appleseeds 13.7 (2011): 2. MasterFILE Premier. Web. 18 Nov. 2011.

Jenkins, Mark. "Yosemite. Daring. Defiant. Free. (Cover Story)." National Geographic 219.5 (2011): 98. MasterFILE Premier. Web. 18 Nov. 2011.


"Yosemite National Park (U.S. National Park Service)." U.S. National Park Service - Experience Your America. N.p., n.d. Web. 18 Nov. 2011. <http://www.nps.gov/yose/index.htm>

Historic Yosemite and Present Yosemite

The photo on the left was taken in 1920, and the photo on the right depicts present day Yosemite.
source: http://home.nps.gov/applications/hafe/hfc/npsphoto2.cfm
           Harpers Ferry Center: National Park Service

Map of Study Area

Yosemite is located in the northern Sierra Nevada Mountains.
www.nps.gov/yosemite

Map of Yosemite National Park.
www.nps.gov/yosemite