Brazil’s Atlantic Forest stores less carbon due to drastic fragmentation

By Jeremy Hance, www.mongabay.com
26 September 2011 The Atlantic Forest in Brazil is one of the most fragmented and damaged forests in the world. Currently around 12 percent of the forest survives, with much of it in small fragments, many less than 100 hectares. A new study in mongabay.com’s open-access journal Tropical Conservation Science finds that the bloodied nature of the Atlantic Forest impacts its capacity to sequester carbon. The study found that 92 percent of the forest stored only half its potential carbon due to fragmentation and edge-effects, which includes damage due to winds and exposure to drought. Researchers measured carbon over three habitats in the Atlantic Forest and found that carbon stocks ranged from 42 tons of carbon per hectare at the forest edge to 579 tons of carbon per hectare in the forest interior. On average, interior forests retained almost three times more carbon than fragmented or edge forests. “Carbon retention is largely dependent on the emergent tree species, but the relative abundance of this ecological group decreases toward forest edges. […] Our results suggest that carbon reduction in edge-affected habitats results (partially) from a reduced abundance of large trees (particularly very tall trees) as well as from lack of carbon compensation by remaining canopy and understorey tree species,” the authors explain. They add that forests had stored less carbon even up to 500 meters from the forest edge. Extrapolating from their results over the whole Atlantic Forest ecosystem, the scientists found that only 8 percent of the forest is currently capable of achieving its full carbon sequestration potential. The rest is impacted by edge-effects and fragmentation. “We must call attention to the potential collapse of Atlantic forest ability to store carbon due to the current configuration of the remaining forest, which is largely dominated by edge-affected habitats,” the authors write, adding that “assuming that human-modified landscapes (most hyper fragmented) may represent the future of most tropical forests, further studies should verify patterns and mechanisms examined here for the sake of tropical forest ecological services.” CITATION: Dantas de Paula, M., Alves Costa, C. P. and Tabarelli, M. 2011 Carbon storage in a fragmented landscape of Atlantic forest: the role played by edge-affected habitats and emergent trees. Tropical Conservation Science Vol. 4(3):-349-358.

Atlantic Forest stores less carbon due to drastic fragmentation