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Habitat Associations and Community Structure of Dipterocarps in Response to Environment and Soil Conditions in B runei D arussalam, N orthwest B orneo
Author(s) -
Sukri Rahayu S.,
Wahab Rodzay A.,
Salim Kamariah A.,
Burslem David F. R. P.
Publication year - 2012
Publication title -
biotropica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.813
H-Index - 96
eISSN - 1744-7429
pISSN - 0006-3606
DOI - 10.1111/j.1744-7429.2011.00837.x
Subject(s) - edaphic , species richness , species evenness , ecology , habitat , vegetation (pathology) , transect , dipterocarpaceae , community structure , plant community , range (aeronautics) , species diversity , rainforest , geography , biology , soil water , medicine , materials science , pathology , composite material
Plant habitat associations are well documented in B ornean lowland tropical forests, but few studies contrast the prevalence of associations across sites. We examined habitat associations and community composition of D ipterocarpaceae trees in two contrasting B ornean lowland mixed dipterocarp forests separated by approximately 100 km: A ndulau (uniform topography, lower altitudinal range, sandy soils) and B elalong (highly dissected topography, higher altitudinal range, clay‐rich soils). D ipterocarpaceae trees ≥ 1 cm diameter at breast height ( dbh ) were censused in 20‐m wide belt transects established along topographic gradients at each site. Dipterocarp density, evenness, species richness, and diversity were significantly higher at A ndulau than B elalong. Significant site associations (with either A ndulau or B elalong) were detected for 19 (52%) of the 37 dipterocarp species tested. D ipterocarpaceae community composition at B elalong correlated with soil nutrient concentrations as well as measures of vegetation and topographic structure, but community composition at A ndulau correlated with fewer habitat variables. Within each site, dipterocarp density, species richness, and diversity were consistently higher on ridges than in slopes and valleys. Significant within‐site associations to topographic habitats were less common at A ndulau (10% of species tested) than at B elalong (15%). We conclude that edaphic and other environmental factors influence dipterocarp community composition at a local scale, and are more important drivers of community structure in the more variable environment at B elalong. Species richness and diversity of dipterocarps on small plots, however, were higher at A ndulau, suggesting that factors other than environmental heterogeneity contribute to contrasts in dipterocarp tree species richness at small scales.