Journal of Tropical Ecology



Edge effects on litterfall mass and nutrient concentrations in forest fragments in central Amazonia


NIGEL C. SIZER a1a2p1, EDMUND V. J. TANNER a1a2c1 and ISOLDE D. KOSSMANN FERRAZ a3
a1 Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EA, UK
a2 Biological Dynamics of Forest Fragments Project, National Institute for Research in the Amazon (INPA), C.P. 478, 69011-970 Manaus, AM, Brazil
a3 Coordenação de Pesquisas em Silvicultura Tropical, Instituto Nacional de Pesquisas da Amazónia, C. P. 478, Manaus, Amazonas, 69011-970, Brazil

Abstract

Forest edges bordering on pasture were created by cutting and burning the surrounding Amazonian lowland rain forest in the dry season (June) of 1990. Litterfall was measured for 3.5 y along transects 10, 50, 100 and 250-m into the forest from the forest edge. Litterfall along the 10-m transects increased by up to 2.5 times that on spatial controls (250-m transects) in the dry season in which the edge was created. In the second dry season after edge creation litterfall at 10-m was lower than on controls, after which it returned to control rates in the second wet season, 1.5 y after edge creation. Litterfall 50-m into the forest was less affected; there was a smaller rise in the dry season in which the edge was cut, and no significant effects after that. At 100-m there was no effect of edge creation on litterfall. Phosphorus concentrations in litterfall were elevated along 10-m transects, 10–12 wk after edge creation, possibly because of reduced retranslocation prior to abscission. The changes in litterfall described here are inextricably linked to the biomass collapse, which occurs near forest-fragment edges in the same area.

(Accepted May 14 2000)


Key Words: Amazon; edges; fragments; litterfall; mineral nutrients; tropical rainforest.

Correspondence:
c1 To whom correspondence should be addressed, at Department of Plant Sciences, University of Cambridge, CB2 3EA, UK. Email: evtl@cam.ac.uk
p1 Present address: World Resources Institute, 1709 New York Avenue, NW, Washington DC 20006, USA.