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Plant Response to Climate Change: Anthropogenic affect on migration

May 10, 2012

Current trends in climate change are altering growing conditions for plants around the world (Watson et al., 1988). As the global warming continues, plant species’ are impacted and forced to shift distributions (migrate), or adapt morphologically or physiological in order to remain within the boundaries of their climatic tolerances. Climatic change also has implications on pathogen interactions. In these next three posts I plan to discuss these conditions emplaced on plant species in order to resist extinction.

Anthropogenic affect on plant migration

Plant populations migrating in response to climate change rely on dispersal capabilities and its own ability to establish in a new site.  Beyond changing where species occur, these migrations may lead to large changes in the amount of habitat area available, which in turn may cause changes in species’ population sizes and influence extinction risk (Tomas et al., 2004; Feeley and Silman, 2010). A species’ potential to colonize a new region (colonization potential) will inevitably depend on its performance relative to resident species (Ibanez et al., 2009). Migrating species’ may end up having to compete with resident species’ for space and resources. Studies show that potential immigrant species are able to establish residency in a new region assuming soil moisture, light and temperature requirements for the immigrant are met, resident species’ have little impact on the immigrant to colonize (Ibanez et al., 2009). Think of it as, if you were to back up everything and move from your California home and move to Alaska. The first think you would have to adapt to would be the climate change, if you can survive that major shock you can then tackle on the residence of Alaska.

In addition to competition with resident species, migratory species also have to respond to anthropogenic (human impact) activities. Patterns of human land-use change may affect the ability of species to persist in the future (Feeley and Silman, 2010).  Land-use effects will be especially pronounced in the context of changing climate as species may migrate into or out of areas that will experience disproportionate levels of human land-use change, thereby either increasing or decreasing the relative benefit of migrating (Feeley and Silman, 2010). Now that you have moved to Alaska, some of your neighbors are not so nice and plow down your house; how are your survival skills now that you have lost everything?

Plant migration in the Andeans has been studied and finds that anthropogenic activities have a high effect on the potential for plant migration. Disturbance model predicts higher rates of deforestation throughout the Amazon and along the base of the Andes, but decreasing rates of disturbance at higher elevations (Feeley and Silman, 2010). Upward migrating species may therefore actually escape highly disturbed areas and benefit by moving up-slope even if the amount of total land area decreases (Feeley and Silman, 2010). Although, in the tropical Andes, human activity have created a tree line associated with cattle grazing and accidentally or intentionally set fires which are used to increase food for cattle ( Keating, 2007; Cierjacks et al., 2008). Anthropogenic effects on tree line and increasing temperatures may result in a fixed upper limit to the distribution of forest species and may greatly reduce range sizes from those predicted based on climate alone (Fig. 1) (Feeley and Silman, 2010). Thus, the Andean species will have less area available to them than if the tree line was to allow the species to migrate up-slope in response to increased temperatures (Feeley and Silman, 2010). In addition the species will be prevented from colonizing the high-elevation plateau and decrease habitat following migration. 

                        ImageFig. 1: land has been converted to pasture and erosion is widespread as a result of human agricultural activities on steep slope. You can see the lack of plant migration up the slope.  (Wikipedia)

The fact that human land-use has such an overriding influence on prediction of how Andean species will respond to future climate change can be viewed as encouragement in that there is still time to change many of our land-use activities (Feeley and Silman, 2010). In other words we decide what species persist and become extinct. This gives humans a lot of power; let’s hope we use that power for the better. Make adaptation to climate change for the better, so that we may all live on this planet together. And remember, plants are essential for life on this Earth, if they go extinct, so does the human population.

Stay tuned for my next post on plant adaptation a morphological and physiological change.

Citation:

Watson et al., 1998: Watson RT, Zinyowera MC, Moss RH (1998) The regional Impacts of Climate Change: An Assessment of Vulnerability. Cambridge University Press, New York, NY, USA

Ibanez et al., 2009: Ibáñez, Inés, James S. Clark, and Michael C. Dietze. “Estimating Colonization Potential of Migrant Tree Species.” Global Change Biology 15.5 (2009): 1173-188.

Thomas et al., 2004: Thomas CD, Cameron A, Green RE et al. 2004. Extinction risk from climate change. Nature, 427, 145-148

Feeley and Silman 2010:“Land-use and climate change effects on population size and extinction risk of Andean plants” FEELEY, KENNETH J., and MILES R. SILMAN. Global Change Biology, 30 Oct. 2009. Web. 6 Jan. 2010.

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One Comment leave one →
  1. May 11, 2012 9:15 am

    I’ve read several articles in the scientific public media (like Scientific American, etc.) about the latitudinal expansion or shifts of many animal species’ home ranges, but I hadn’t given much thought to the other kingdoms of life. I also hadn’t really given much thought to the shift in elevation associated with climate change. Very interesting!

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