Works Cited and Photo Credits

Works Cited

Butcher, Bill.  Canada Lynx and Climate Change.  Available from: http://www.fws.gov/northeast/climatechange/stories/lynx.html  Accessed April 10, 2012.

Butcher, Bill.  Invasive Plants Move North.  Available from: http://www.fws.gov/northeast/climatechange/stories/kudzu.html  Accessed April 10, 2012.

Dettmers, Randy.  Bicknell’s Thrush: Shrinking Islands and Red Squirrel Population Explosion: Impact to Bicknell’s Thrush.  Available from: http://www.fws.gov/northeast/climatechange/stories/bicknellsthrush.html  Accessed April 20, 2012.

Hilke, Christopher.  (2011).  Climate Change: What is at Stake for Wildlife?.  Available from: http://blog.nwf.org/2011/10/climate-change-what-is-at-stake-for-wildlife-2/  Accessed March 3, 2012.

Reynolds, Debra & Wolff, Frank.  (2011).  Vermont: Climate Change Poses Challenges for the Bicknell’s Thrush.  Available from: http://www.fws.gov/news/blog/index.cfm/2011/5/23/Vermont-Climate-Change-Poses-Challenges-for-the-Bicknells-Thrush--Shrinking-Habitat-Nestinvadin  Accessed April 19, 2012.  

Photos

Bargeron, Chuck.  Available from: http://www.nps.gov/plants/alien/fact/mivi1.htm  Accessed April 26, 2012

Cornell Lab of Ornithology.  Available from: http://www.birds.cornell.edu/bfl/speciesaccts/bicthr.html  Accessed April 26, 2012

Fotolia/Kwest.  2011.  Available from: http://www.motherearthnews.com/nature-community/climate-change-science-zm0z11zkon.aspx  Accessed April 26, 2012

Gahbauer, Marcel.  2005.  Available from: http://www.migrationresearch.org/mbo/id/bith.html  Accessed April 26, 2012

Pfieffer, Brian.  Available from: http://www.wingsphotography.com/bickthru.html  Accessed April 26, 2012

Rosing, Norbert.  Available from: http://animals.nationalgeographic.com/animals/mammals/lynx.html  Accessed April 26, 2012

Swearingen, Jil M.  Available from: http://www.nps.gov/plants/alien/fact/ceor1.htm  Accessed April 26, 2012

Swearingen, Jil M.  Available from: http://www.nps.gov/plants/alien/fact/pumo1.htm  Accessed April 26, 2012

U.S. Fish and Wildlife Service.  Available from: http://www.fws.gov/mountain-prairie/species/mammals/lynx/  Accessed April 26, 2012

 

Invasive Plants and the Threats They Pose

While it can seem as though climate change mainly affects indigenous species' ability to thrive in their changing environments by altering the conditions that they have adapted to survive in, another equally large threat is posed by the onset of invasive plant species in response to warming conditions. 

Asiatic Bittersweet - Swearingen

What are some of the most threatening plant species?

• Asiatic Bittersweet

• Japanese Stiltgrass

• Kudzu

These species are able to grow and spread so rapidly that, in some cases, wildlife managers have little to no time to take preventive measures to stop their arrival. When invasive plant species arrive, they affect the ability of native plants to successfully grow and regenerate. The kudzu, which is known as "the vine that ate the south," (Butcher 2) can grow so rapidly that it is able to choke out entire native species. What happens to the native animal species when invasive plant species arrive and begin to choke out the native plant species in an area?

Japanese Stiltgrass - Bargeron

• "Introducing additional stressors to an already fragile ecosystem can have a devastating impact on native plants and animals. Once an invasive plant species becomes ingrained, it crowds out other native species that the region's animals have come to depend on." (Butcher 2)

• Thinning out of native plants that native animals rely on for food leads to increased food competition between animals.

• Native animals not only rely on native plants for food, but for shelter as well. When invasive plants like the Asiatic bittersweet and kudzu become ingrained and choke out larger, fuller plant species, many animals lose necessary cover and find themselves threatened by predatory animals that they used to be able to hide from. 

Kudzu - Swearingen

Studies conducted concerning invasive plant species have resulted in some concerning news. According to climate models based on current warming trends, "In one hundred years... kudzu and other invasive plants may have a stranglehold on the beloved New England forests." (Butcher 2) While conditions in the Northeast remain too cold for the time being for such plants to thrive, the threat will remain imminent so long as climate change continues at its already rapid pace.

Affected Species: The Canadian Lynx

U.S. Fish and Wildlife Service

The Canadian lynx is another Northeastern species that is suffering from the effects of climate change and warming conditions. The Canadian lynx is considered a specialty species, because of its "evolved physical attributes, like large saucer-like paws, that provide a competitive advantage in deep snow habitats." (Butcher 1) The Canadian lynx feeds almost exclusively on the snowshoe hare, another species that is threatened by the changing climate. The snowshoe hare thrives in regenerating spruce and balsam fir stands, and since their population is directly related to the structure and ecology of Northeastern forests, the Canadian lynx relies on the maintenance and consistency of these forests for its own survival. However, diminishing forests are not the only threat to the Canadian lynx. What other factors related to climate change pose a threat to the Canadian lynx?

Rosing

• As a specialized species, the Canadian lynx relies on its evolved physical attributes to out-compete other predatory species for food.

• Decreased snowfall over the past few years has created conditions in which other predators such as bobcats and fisher cats are able to out-compete the lynx in terms of hunting.

• As the climate continues to warm, the Canadian lynx has no choice but to recede with the snowfall, because it is much less suited for adaptation to warmer climates than its competitive species, largely in part to its evolved physical attributes that are built for snowy conditions.

(Butcher 1)

Affected Species: The Bicknell's Thrush

Gahbauer 2005

While many species of birds have relatively wide breeding ranges, the Bicknell's thrush, a longtime resident of the Vermont and New England mountain top conifer forests, "has one of the most restricted breeding ranged of any North American bird." (Reynolds & Wolff 2011) Although the Bicknell's thrush is a migratory bird, it relies on these mountain top forests as its breeding ground. The Bicknell's thrush survives on a diet that consists mainly of insects. Their biggest threat comes from the red squirrel, a species that typically consumes spruce and fir cones, but is known to raid the nests of the Bicknell's thrush to prey on both eggs and young birds. The gradual Northeastern climate change that has been occurring has had a negative impact on the Bicknell's thrush in more ways than one. Not only is the structure of the forest they rely on slowly changing, but their food supply as well. In addition, there is the looming threat of increased red squirrel populations in years to come as weather patterns shift. (Dettmers)

Bicknell's Thrush Breeding Range - Cornell

How as climate change affected the Bicknell's thrush so far?

• Warming conditions have allowed for deciduous tree species to grow higher and higher up on the mountains that were previously covered only in evergreen tree species.

• Increased numbers of deciduous trees in these forests have lead to the thinning and shrinking of the conifer forests that are crucial breeding grounds for the Bicknell's thrush.

• Increased numbers of deciduous trees in the Bicknell's thrush breeding range promote the arrival of more species of birds, leading to increased food competition.

• Changes in weather patterns have affected the arrival of the insect species that the Bicknell's thrush relies on for food, which arrive in response to climate, while the Bicknell's thrush arrives in response to day length.

• Warmer climates have lead to the potential for increased, more robust cone crops from the spruce and fir trees that remain in the conifer forests, which, in turn, lead to the potential for increased red squirrel populations and a higher threat to the Bicknell's thrush.

(Dettmers)

Pfieffer

While forest management can play a minor role in controlling what tree species inhabit the Vermont and New England mountain tops, it is difficult to control a rapidly changing environment. Currently, the Bicknell's thrush is being studied and monitored by a number of organizations including the U.S. Fish and Wildlife Service to study and determine the bird's ability to adapt to predicted ecological changes. The Bicknell's thrush is just one of the innocent victims of the ongoing threat of climate change.

Potential Effects of Climate Change

Fotolia/Kwest 2011

Over the past decade, climate change has become an extremely important topic of discussion in both the scientific community and the general population. While climate change is undeniably largely human-induced, it unfortunately has taken a much heavier toll on innocent wildlife populations than on the human population. While to many, the effects of climate change on wildlife populations and wildlife ecology seem obvious, others don't realize the inevitable harmful effects of increased temperatures and changing weather patterns.

What are some of the negative impacts that climate change can, and in many cases already has, have on wildlife populations?

• Changes in weather patterns influence changes in water supply and availability.

• Warming conditions influence the arrival of invasive plant species.

• Warming conditions influence the arrival of more, better adapted competitive species.

• Changes in season length influence the overall structure and diversity of plant life in wildlife ecosystems.

In the Northeast, several species of animals have already begun suffering the effects of climate change, largely in part to the thinning of our mountain top evergreen conifer forests. What are some of these species?

• The Bicknell's Thrush

• The Boreal Chickadee

• The American Marten

• The Canadian Lynx

(Hilke 2011)