Overall habitat diversity may increase in alpine zones
By Summit Voice
SUMMIT COUNTY — Under the most commonly predicted global warming scenarios, mountains could become an important refuge for alpine plant species because of the wide variety of micro-climates in close proximity to each other.
Cold microclimates will shrink, and warmer micro-climates will expand, adding to the overall habitat diversity many mountain areas. Plants may be able to find a suitable habitat niche very close their existing home as the climate changes, the researchers suggested.
“It is known from earlier geological periods that mountains were always important for survival of species during periods of climatic change such as in glacial cycles, because of their habitat diversity, said Christian Körner, of the University of Basel, in Switzerland. “Mountains are therefore particularly important areas for the conservation of biodiversity in a given region under climatic change and thus deserve particular protection,” Körner said in a press release announced the results of recent study published in the Journal of Biogeography.
“We found that the occurrences of plant species across these mosaics of warmth match with their known temperature preferences,” explained Körner. “This means that rugged alpine terrain offers refuge habitats — or at least stepping stones to these — at short distance, for both small plants and animals that prefer cool life conditions.”
The study was done over two growing seasons in the central Swiss Alps. Researchers used a high resolution infrared camera and hundreds of soil sensors to monitor temperatures experienced by plants in alpine landscapes, then used known ‘indicator values’ for thermal preferences of plant species permitted to link microhabitat life conditions with biodiversity, the number and abundance of species.
“In this study we examined if different vegetation types and plant species occur under different micro-habitat temperatures,” said Körner. “We also estimated the potential loss and shift in abundance of micro-habitat temperatures under a warming climate scenario.”
“Comparing various slopes, the study made it obvious that slope exposure and ruggedness of terrain produce a broad spectrum of life conditions not seen over similar areas in forests or in the forelands and plains,” said Scherrer. “While it was known from measurements with thermometers that plant and air temperatures can differ substantially in alpine terrain, the high degree of sustained thermal contrasts among habitats still came as a surprise.”
Depending on exposure, low stature alpine vegetation warms up dramatically when the sun is out, but under cloudy weather part of that warmth remains stored in the soil, which also makes nights cosier for roots in many places.
The authors simulated the frequency of certain temperatures for a 2 degrees warmer climate with a computer, and found that only 3 percent of all types of temperature conditions will disappear. So, while the extent of some of the cooler habitats will shrink, importantly, they will not be lost altogether.
The authors found that warm habitats become more frequent, and new, warmer habitats will become established, so habitat diversity will in fact increase. The study also illustrates that weather station data is not a suitable basis for projecting future life conditions of organisms in such high elevation terrain.
“We suggest that alpine terrain is, for the majority of species a much ‘safer’ place to live under conditions of climate warming, compared to flat terrain, which offers no short-distance escapes from the changing temperatures,” said Scherrer.