Mountain plant boundary can help monitor climate change

Nadya Anscombe in Environmental Research Web reports on some fascinating research: Researchers in Austria have, for the first time, quantitatively defined the transitional boundary or ecotone between alpine plants that can handle occasional snowfall and frost and nival plants, which grow under snow and need longer snow cover, on Mount Schrankogel in the Austrian Alps. They believe that this alpine-nival ecotone can be used as a sensitive tool in the monitoring of the effect of climate change on the biodiversity of mountainous ecosystems.

Michael Gottfried and colleagues from the University of Vienna used the same statistical methods as are employed to calculate the summer snowline and found that the alpine-nival ecotone and the summer snowline coincided very closely.

"We are very pleased to at last have a robust and mathematically sound method for showing what we, as field ecologists, already knew from observations," Gottfried told environmentalresearchweb. "Many people believe that the boundary between trees and alpine plants is the only ecotone in the Alps. But we have shown there is another important ecotone in the higher mountains – the alpine-nival ecotone at around 3000 m."

Alpine plants dominate extended regions of dwarf shrub heath or grasslands (alpine tundra) located at lower altitudes while the cryo-tolerant nival plants grow at higher altitudes in scattered cushion fields, restricted to a few favourable habitats. The research has shown that, as climate change moves the summer snowline up the mountain, so the ecotone follows. "In the 10 years between 1994 and 2004, the alpine-nival ecotone moved around 20 m up the mountain," said Gottfried.

…Monitoring the movement of the alpine-nival ecotone and the snowline is important because as the snowline moves up the mountain, nival plants are in danger of becoming extinct. While Gottfried admits that the disappearance of these plants may not have a direct economic impact, he believes that "their loss would greatly impact the biodiversity treasure and genetic diversity of mountainous regions". The researchers now want to apply their techniques to other mountainous regions around the world….

From 1839, Physical Geography. Humboldt’s Distribution of Plants in Equinoctial America, According to Elevation Above the Level of the Sea.