Fragmentation impairs the microclimate buffering effect of tropical forests

PLoS One. 2013;8(3):e58093. doi: 10.1371/journal.pone.0058093. Epub 2013 Mar 4.

Abstract

Background: Tropical forest species are among the most sensitive to changing climatic conditions, and the forest they inhabit helps to buffer their microclimate from the variable climatic conditions outside the forest. However, habitat fragmentation and edge effects exposes vegetation to outside microclimatic conditions, thereby reducing the ability of the forest to buffer climatic variation. In this paper, we ask what proportion of forest in a fragmented ecosystem is impacted by altered microclimate conditions driven by edge effects, and extrapolate these results to the whole Atlantic Forest biome, one of the most disturbed biodiversity hotspots. To address these questions, we collected above and below ground temperature for a full year using temperature sensors placed in forest fragments of different sizes, and at different distances from the forest edge.

Principal findings: In the Atlantic forests of Brazil, we found that the buffering effect of forests reduced maximum outside temperatures by one third or more at ground level within a forest, with the buffering effect being stronger below-ground than one metre above-ground. The temperature buffering effect of forests was, however, reduced near forest edges with the edge effect extending up to 20 m inside the forest. The heavily fragmented nature of the Brazilian Atlantic forest means that 12% of the remaining biome experiences altered microclimate conditions.

Conclusions: Our results add further information about the extent of edge effects in the Atlantic Forest, and we suggest that maintaining a low perimeter-to-area ratio may be a judicious method for minimizing the amount of forest area that experiences altered microclimatic conditions in this ecosystem.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Brazil
  • Conservation of Natural Resources*
  • Microclimate*
  • Temperature
  • Time Factors
  • Trees / physiology*
  • Tropical Climate*

Grants and funding

Fieldwork was funded by the Royal Society of London (Research Grant RG080214, http://royalsociety.org/), and CBL was funded by the Natural Environment Research Council (Grant Number NE/H016228/1, http://www.nerc.ac.uk). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.