title: Markedly Divergent Tree Assemblage Responses to Tropical Forest Loss and Fragmentation across a Strong Seasonality Gradient.
abstract: We examine the effects of forest fragmentation on the structure and composition of tree assemblages within three seasonal and aseasonal forest types of southern Brazil, including evergreen, Araucaria, and deciduous forests. We sampled three southernmost Atlantic Forest landscapes, including the largest continuous forest protected areas within each forest type. Tree assemblages in each forest type were sampled within 10 plots of 0.1 ha in both continuous forests and 10 adjacent forest fragments. All trees within each plot were assigned to trait categories describing their regeneration strategy, vertical stratification, seed-dispersal mode, seed size, and wood density. We detected differences among both forest types and landscape contexts in terms of overall tree species richness, and the density and species richness of different functional groups in terms of regeneration strategy, seed dispersal mode and woody density. Overall, evergreen forest fragments exhibited the largest deviations from continuous forest plots in assemblage structure. Evergreen, Araucaria and deciduous forests diverge in the functional composition of tree floras, particularly in relation to regeneration strategy and stress tolerance. By supporting a more diversified light-demanding and stress-tolerant flora with reduced richness and abundance of shade-tolerant, old-growth species, both deciduous and Araucaria forest tree assemblages are more intrinsically resilient to contemporary human-disturbances, including fragmentation-induced edge effects, in terms of species erosion and functional shifts. We suggest that these intrinsic differences in the direction and magnitude of responses to changes in landscape structure between forest types should guide a wide range of conservation strategies in restoring fragmented tropical forest landscapes worldwide.
authors: Departamento de Botânica, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
authors: Rodrigo L L
authors: RL
authors: Orihuela
authors: School of Environmental Sciences, University of East Anglia, Norwich Research Park, Norwich, United Kingdom.
authors: Carlos A
authors: CA
authors: Peres
authors: Departamento de Botânica, Universidade Federal de Pernambuco, Recife, Brazil.
authors: Gabriel
authors: G
authors: Mendes
authors: Departamento de Botânica, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
authors: João A
authors: JA
authors: Jarenkow
authors: Departamento de Botânica, Universidade Federal de Pernambuco, Recife, Brazil.
authors: Marcelo
authors: M
authors: Tabarelli
mesh_terms: D001938:Brazil; D003247:Conservation of Natural Resources; D017753:Ecosystem; D065928:Forests; D012621:Seasons; D014197:Trees / Q000145:classification* / Q000254:growth & development*; D014329:Tropical Climate