Plants Go Down and Not Up
When it gets warmer vegetation and animal life adapt and change. Different populations move in from warmer climes to former colder climes. One widely held assumption is that it gets colder as the elevation gets higher so that as the climate gets warmer life that has adapted to a warmer environment will go higher pushing the colder based life forms out. In a paper published January 20th in the journal Science, a University of California researcher and his co-authors challenge a widely held assumption that plants will move uphill in response to warmer temperatures. Between 1930 and 2000, instead of colonizing higher elevations to maintain a constant temperature, many California plant species instead moved downhill an average of 260 feet.
Many forecasts say climate change will cause a number of plants and animals to migrate to new ranges or become extinct. That research has largely been based on the assumption that temperature is the dominant driver of species distributions. However, Greenberg (an assistant project scientist at the UC Davis Center for Spatial Technologies and Remote Sensing) said the new study reveals that other factors, such as precipitation, may be more important than temperature in defining the habitable range of these species.
The findings could have global relevance, because many locations north of 45 degrees latitude (which includes the northernmost United States, virtually all of Canada and Russia, and most of Europe) have had increased precipitation in the past century, and global climate models generally predict that trend will continue, the authors said.
He added that the study underlines the importance of an investment in basic science, as the results are based on historical data collected by the U.S. Forest Service in the 1930s, a program that was supported by New Deal spending after the Great Depression.
There are many factors that affect how plant life will respond to environmental change. Temperature and precipitation are just two variables.
The timing of phenological events such as flowering are often related to environmental variables such as temperature. Changing environments are therefore expected to lead to changes in life cycle events, and these have been recorded for many species of plants. These changes have the potential to lead to the asynchrony between species, or to change competition between plants. Flowering times in British plants for example have changed, leading to annual plants flowering earlier than perennials, and insect pollinated plants flowering earlier than wind pollinated plants; with potential ecological consequences.
It is likely that indirect impacts are to be equally important in determining the response of plants to climate change.
A species whose distribution changes as a direct result of climate change may invade the range of another species for example, introducing a new competitive relationship. The range of a symbiotic fungi associated with plant roots may directly change as a result of altered climate, resulting in a change in the plants distribution.
A pathogen or parasite may change its interactions with a plant, such as a pathogenic fungus becoming more common in an area where rainfall increases.
These indirect factors are also affected by climate change and will have impact on how the plant environment will respond.
For further information: http://www.universityofcalifornia.edu/news/article/24851