Spread of Bambusa bambos (L.) Voss influences litter-dwelling arthropod communities in native forests: a case study from Sri Lanka

Both native and non-native bamboo populations can expand their distributions in a rather irregular manner, inflicting changes in native vegetation with potential consequences for litter-dwelling arthropod communities. To our knowledge, no studies have been undertaken to explore the impacts of bamboo spread on litter-dwelling arthropods. This study examined the impacts of Bambusa bambos, a spreading native bamboo species, on abundance and order richness of litter-dwelling arthropods in tropical moist evergreen forests. Bamboo-rich and non-bamboo forests were compared in three study sites at Moragahakanda in the Central Province of Sri Lanka. Arthropods were sampled from leaf litter and individuals were categorised into their respective orders. Arthropod abundance and order richness were higher in bamboo-rich forests than in non-bamboo forests across all sites, indicating more hospitable micro-habitat conditions following bamboo spread. Litter-dwelling arthropods belonging to orders Blattodea, Hymenoptera, Diptera, Lepidoptera and Orthoptera were either more prevalent or more frequently associated with bamboo-rich forests than non-bamboo forests, suggesting a potential shift in community structure. The abundance and order richness of litter-dwelling arthropods in non-bamboo forests was explained by environmental variables, whilst no such associations were observed in bamboo-rich forests. The overall findings indicate that the spread of bamboo may facilitate litter-dwelling arthropods and cause a compositional shift in taxonomic assemblages, perhaps as a result of changes in the micro-habitat conditions on the forest floor.