Area and edge effects on leaf-litter decomposition in a fragmented Subtropical Dry Forest

MORENO MARÍA LAURA; BERNASCHINI, MARÍA LAURA; PERÉZ-HARGUINDEGUY NATALIA; VALLADARES, GRACIELA

Oporto

Congreso; 7th Meeting of young researchs of University of Porto; 2014

Universidad do Porto

South American tropical and subtropical dry forests are disappearing at an alarming rate, with 80 % deforestation of the original area being recorded in the last decade. Deforestation involves habitat loss and fragmentation, i.e. the transformation of a forested area to a number of smaller forest remnants embedded in a matrix with different land use, usually agricultural. In forest remnants, changes in soil enviroment (i.e. the sum of soil physicochemical and biological properties, and microclimate) could have significant effects on key ecosystems processes. In this work, we experimentally analyzed leaf-litter decomposition in a fragmented Chaco Serrano forest in central Argentina. We asked whether decomposition can be affected by forest area and edge effects. By using a common substrate (from native plants) we avoided effects mediated by changes in litter quality, thus focussing on effects of in situ conditions for decomposition. We collected freshly senesced leaf material of two abundant native species and constructed 72 litter-bags. The litter-bags were incubated during 120 days in the edge and interior of 12 forest remnants (0.57-1000 ha). We analized by linear mixed models if the decomposition rate (% dry weight mass loss) of a common substrate varied with fragment size and between forest edge and interior. Decomposition declined with fragment size, with no significant effects of location (edge/interior). Our results suggest that in situ conditions for decomposition may change as a consequence of forest fragmentation, specifically as a result fragment size. The results also suggest that the mechanisms underlying such effects may involve changes in decomposer/detritivores biota.