Safety in the Slopes: High Elevation May Be Keeping Some Forests Intact

[Buster's Uncle]

Safety in the Slopes: High Elevation May Be Keeping Some Forests Intact
By Douglas Main | Takepart.com 7 hours ago


     
If you're a forest, the safest place to live may be on the steep slopes of mountains. Around the world, new research shows that places with high elevation have the highest relative concentration of trees and forests.

"Tree cover is higher on slopes nearly everywhere where there is significant human modification of the landscape," said Brody Sandel, a researcher at Aarhus University in Denmark.

That's because it's easier to log forests in plains and lowland areas. While the finding may seem intuitive, it wasn't known how widespread this pattern was, according to Sandel.

A study co-authored by the researcher and his colleague Jens-Christian Svenning, and published this week in the journal Nature Communications, found that the pattern held true across the globe, regardless of scale. Whether the researchers compared a small hill to a surrounding plain, or contrasted mountainous countries with flat ones, they got the same result: There are more trees higher up.

The finding has at least two contrasting implications for animals and plants of our planet's forests. On the one hand, mountainous areas often hold a larger variety of species, especially the more rare types, than surrounding flat regions, "so the loss of forests from flat areas is likely to cause less biodiversity loss than if the same clearing happened on slopes," Sandel says.

On the other hand, as forests become limited to slopes, they're likely to become more separated, discontinuous and fragmented. Fragmented areas typically provide for less biodiversity because they limit the dispersal of animals and plants, and because, for example, some species prefer the interior forest habitat that's uncommon in these areas.

What does all these mean for conservation? "As for what can be done, I do not think the study provides much of a prescription, unfortunately," Sandel says. "It might suggest that we should prioritize the conservation of flat areas a bit more, to preserve connections among fragments and species that require lowland habitat that is otherwise threatened by land use."

Joe Kiesecker, a lead scientist with The Nature Conservancy who wasn't involved in the study, said that the truth of the findings is reflected in the fact that most protected areas are already found at higher elevations. "It's already had an effect," he says.

That's because lowlands are generally more desirable for agriculture and development, and why most native grasslands around the world have been converted to agriculture or otherwise destroyed.

The study gives conservationists the chance to intentionally preserve more lowlands, although achieving that in the face of population growth will be a challenge, according to Kiesecker. "That's the exciting part — since we know where change is likely to happen, we can start to be more proactive, whereas in the past conservation has been mostly reactive."

Deforestation remains a huge and growing problem in many areas, for example in places like Borneo and Madagascar, and in many tropical forests.

Overall, from 2000-2005 (the latest date range for which data are available), forest cover decreased only slightly worldwide, according to the study. Tree cover increased a small amount over this time period, which could be explained in part by abandonment of former agricultural land in Eastern Europe (where trees have grown back), tree-planting programs in China and growth of trees in savannahs (perhaps due to increases in carbon dioxide), the study noted. 

Unlike many ecological studies, this one also incorporated sociological and economic factors. And it found they played an important role on a country-by-country basis: Strong environmental governance and low population stress were linked with higher concentrations of forests in mountainous areas.

"It is remarkable that political and socioeconomic indicators...create a pattern in tree cover that is detectable from space," as measured and imaged by satellites, Sandel says. "We are altering the world in a major way, and the conditions of human societies are shaping that alteration."

http://news.yahoo.com/forests-last-frontier-steep-slopes-192653008.html