Logging road in Borneo. Click image for more information. (Photo by R. Butler)
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HABITAT FRAGMENTATION AS A THREAT TO RAINFORESTS
By Rhett Butler | Last updated July 31, 2012
Habitat fragmentation is a serious threat to biodiversity and patches of forest worldwide (also see
sections 9 and 10). As great expanses of forest are increasingly chopped into smaller blocks, edge effects alter the the flora and fauna of forests. Fragmented patches of forest are subject to drying winds that increase the frequency of tree falls. Tree falls tear gaps in the canopy, destroying its function of moderating the humidity, temperature, and heat conditions of the forest floor. These changes affect the species that inhabit the forest patch, usually reducing diversity. Many rare species that dwell in the deep primary forest are unable to cope with the new conditions and are replaced by more common, weedier species. The drier forest conditions also mean that agricultural fires set in the surrounding scrubland and savanna are more likely to burn through the forest patch. During the Indonesian and Brazilian fires of 1997 and 1998, such forest patches went up in smoke at an alarming rate. Fragmented forests also suffer a loss of biomass—up to 36 percent—in the first few years after fragmentation.
More information on fragmentation >>
Review questions:
- Why is forest fragmentation bad for rainforest biodiversity?
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WEEKLY NEWSLETTER
INTERACT
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Recent news
Loss of big fruit-eating birds impacting trees in endangered rainforests
(05/31/2013) The extinction of large, fruit-eating birds in fragments of Brazil's Atlantic rainforest has caused palm trees to produce smaller seeds over the past century, impacting forest ecology, finds a study published in the journal Science.
Still hope for tropical biodiversity in human modified landscapes
(04/09/2013) As primary forests become increasingly rare and expensive to protect, many ecologists are looking to better management of Human Modified Landscapes (HMLs) to shepherd and shield biodiversity in the tropics. Secondary forests, selectively logged forests and lands devoted to sustainable agriculture already play an important role in conservation efforts. However, the idea that HMLs will serve as a "Noah's Ark" for biodiversity, is controversial.
Peruvian night monkey threatened by vanishing forests, lost corridors
(03/18/2013) The Peruvian night monkey (Aotus miconax) is one of the world's least known primates, having never been studied in the wild--until now. Found only in the cloud forests of northern Peru, a group of scientists with Neotropical Primate Conservation and the National University of Mayor San Marcos have spent 12 months following a single group of this enigmatic monkey species in a small forest patch. The results of their research, published in mongabay.com's open access journal Tropical Conservation Science, shows that protecting forests, even small forest fragments, is vital to the species' survival.
New giant flying frog discovered near city of 9 million
(01/09/2013) Jodi Rowley is no stranger to discovering new amphibians—she's helped describe over 10 in her short career thus far—but still she was shocked to discover a new species of flying frog less than 100 kilometers from a major, bustling Southeast Asian metropolis, Ho Chi Minh City. Unfortunately, the new frog, dubbed Helen's tree frog (Rhacophorus helenae), may be on the verge of extinction, according to the description published in the Journal of Herpetology.
Rehabilitated orangutans in danger if industrial project proceeds in Borneo
(10/22/2012) The proposed extension of an industrial area in East Kalimantan, Indonesia will likely mean the end of a population of rehabilitated orangutans who reside there, according to the Indonesian environmental group Peduli Teluk Balikpapan. The Kariangau Industrial Area (KIK) will comprise 5,130 hectares of land currently covered by hardwood forests and mangroves when completed, including one third of orangutan habitat in Sungai Wain forest—a crucial portion that is not within the boundaries of the Sungai Wain Protection Forest and therefore not under any governmental protection.
More news on fragmentation
More rainforest news
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(08/15/2012) When the Portuguese first arrived on the shores of what is now Brazil, a massive forest waited for them. Not the Amazon, but the Atlantic Forest, stretching for over 1.2 million kilometers. Here jaguars, the continent's apex predator, stalked peccaries, while tapirs waded in rivers and giant anteaters unearthed termites mounds. Here, also, the Tupi people numbered around a million people. Now, almost all of this gone: 93 percent of the Atlantic Forest has been converted to agriculture, pasture, and cities, the bulk of it lost since the 1940s. The Tupi people are largely vanished due to slavery and disease, and, according to a new study in the open access journal PLoS ONE, so are many of the forest's megafauna, from jaguars to giant anteaters.
(08/15/2011) For over 30 years, hundreds of scientists have scoured eleven forest fragments in the Amazon seeking answers to big questions: how do forest fragments' species and microclimate differ from their intact relatives? Will rainforest fragments provide a safe haven for imperiled species or are they last stand for the living dead? Should conservation focus on saving forest fragments or is it more important to focus the fight on big tropical landscapes? Are forest fragments capable of regrowth and expansion? Can a forest—once cut-off—heal itself? Such questions are increasingly important as forest fragments—patches of forest that are separated from larger forest landscapes due to expanding agriculture, pasture, or fire—increase worldwide along with the human footprint.
(10/13/2010) A new study in Biological Conservation has shown that edge forests and forest patches are more vulnerable to burning because they are drier than intact forests. Using eight years of satellite imagery over East Amazonia, the researchers found that desiccation (extreme dryness) penetrated anywhere from 1 to 3 kilometers into forests depending on the level of fragmentation.
(11/27/2006) Forest fragmentation is rapidly eroding biodiversity in the Amazon rainforest and could worsen global warming according to research to be published this week in the journal Proceedings of the National Academy of Sciences. "Rainforest trees can live for centuries, even millennia, so none of us expected things to change too fast. But in just two decades-a wink of time for a thousand year-old tree-the ecosystem has been seriously degraded." said Dr. William Laurance, a scientist at the Smithsonian Tropical Research Institute in Panama and leader of the international team of scientists that conducted the research.
