How small is too small? The uncertain fate of Madagascar’s forest fragments

first_imgMany of the largest trees in the protected area didn’t recover after being scorched by a fire in 2014. Photo by Rowan Moore Gerety for Mongabay.Sohisika trees, represented by roughly 200 to 300 mature plants all told, are considered to be at high risk for extinction. Ankafobe holds just 15 of them, protected since 2005 as the centerpiece of the 150 hectare community reserve The reserve is supported by the Missouri Botanical Garden (MBG) and is now in the process of achieving legal designation as a New Protected Area.The other sohisikas are scattered on the savannah surrounding the reserve and in a handful of green slivers that mark the clefts between neighboring hills — areas with no environmental protection and that face the constant threat of brush fires during the dry season. Until 2014, another 50 of the trees could be found a few miles away at a site managed by the Antananarivo-based group Madagasco Environnement. But recent satellite imagery shows that the valley where the sohisika were concentrated is now mostly bare.As logging, charcoal production, and the clearing of woods for farmland took their cumulative toll on Madagascar’s forests in the second half of the 20th century, the country’s total forest cover fell by 40 percent. But fragmentation of the forests that remained progressed even more quickly. Between 1950 and 2000, there was an 80 percent reduction in the area covered by “core forests,” which lie at least one kilometer from the nearest edge, a trend mirrored in forests around the world.The result has been a splintering of remaining habitat for endangered species across Madagascar, and a scramble among conservationists to figure out how best to protect what’s left.Map courtesy of Google Maps.“The tragedy of Madagascar is that the forest there is in pieces,” said Stuart Pimm, an expert on the biology of fragmentation and extinction who teaches at Duke University in North Carolina. “When it comes to fragmentation, there’s bad news, there’s worse news, and there’s worse news still.”As the size of a given patch of forest dwindles, Pimm explained, its basic geometry changes too, so that there is much more “edge,” or perimeter, for each hectare of forest. It’s similar to what happens when a child cuts a single sheet of paper into a paper snowflake. These multiplying forest edges make it easier for predators to reach their prey under the canopy, expose trees more readily to the effects of drought, and give brush fires purchase in forests they wouldn’t otherwise burn. Madagascar’s total forest cover fell by 40 percent in the second half of the 20th century, but fragmentation of the forests that remained progressed even more quickly.Conservation groups are working to conserve a number of small fragments. In Ankafobe, the local community has come together to reconnect three scraps of forest and defend them against fire.The risk that both animates this work and threatens to make it obsolete is that fire, agriculture, or other pressures could reduce the size of these fragments below some basic threshold of ecological viability.This is the third story in Mongabay’s multi-part series “Conservation in Madagascar.” ANKAFOBE, Madagascar — When he first told colleagues at the Missouri Botanical Garden that lemurs still lived in the forest in Ankafobe, Jean Jacques Rasolofonirina said he was met with disbelief. “The forest is too small,” he recalled one saying—just 27.76 hectares, to be exact, split into three fragments scarcely larger than three or four New York City blocks.But these narrow wooded valleys still hold three species of lemurs, and owls, frogs, and bats besides. Solofo, as friends and colleagues call him, rattled off their Latin names as he walked down the narrow path that enters the forest from the main road. He stopped to mimic the call of a Malagasy paradise flycatcher (Terpsiphone mutata) perched on a nearby branch, and pointed out seedlings planted to fill in a small clearing beside a stream.After a few minutes, he gestured at a gnarled, windswept tree at the edge of the woods with smooth gray bark and small, waxy leaves. “That,” Solofo said, “is the sohisika,” or Schizolaena tampoketsana, one of a handful of plant species found nowhere on the planet outside the rolling grasslands here, in a single district northwest of Madagascar’s capital city, Antananarivo.last_img

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