Biodiversity and Plant Litter Decomposition in Streams

Abstract

The main factors influencing litter decomposition in streams are substrate quality, metazoan feeding, microbial activity and environmental context. However, the biodiversity of both resources (litter) and consumers (mostly detritivorous invertebrates) can also influence decomposition, with consequences for stream ecosystem functioning. With regard to leaf litter diversity, in general, decomposition rates increase with litter species richness, but this relationship shifts in response to the environmental context, e.g., nutrient availability in the water column, water flow, and differential shredder feeding rates. Increasing shredder diversity tends to result in faster decomposition rates, due to facilitative and complementarity effects related to intra- vs. interspecific interactions. Multitrophic diversity is studied the least, and justifiably so given the complexities of proper experimental needs. However, available evidence suggests that loss of taxa at multiple trophic levels results in altered rates decomposition compared to those expected from intact food webs.