Abstract ID: 560

A Basin wide analysis of the relationship between rainfall quantity and distribution and production of fine litter in lowland forest ecosystems.

In tropical regions seasonality has largely been defined by the amount and distribution of rainfall over the year rather than shifts in temperature ranges. Recent work suggests that subtle shifts in rainfall patterns can result in significant effects on both the quantity and quality of litter produced in tropical humid to wet rainforests. Litterfall production and decomposition are key components in the cycling of biologically available nutrients and have potentially large secondary feedbacks to the rate and size of C fluxes as well. Given the potential impacts of both land use change and predicted climate change on rainfall patterns in the Amazon Basin, a more detailed understanding of the interactions between rainfall and litter dynamics on both short term ( monthly) and longer term (annual to decadal) time scales is essential to our ability to predict responses of C and nutrient cycles to these alterations. The goal of this study was to examine the relationship between litter productivity and rainfall at several spatial and temporal scales using data reported in the literature from a variety of sites across the Amazon Basin. We found a strong positive relationship between total annual precipitation and production of fine litter (leaves, fruits and flowers and fine twigs). The patterns with seasonality (increased number of months with less than 200 mm of rainfall) were less significant overall. Under scenarios of reduced quantities of and more seasonal distribution of rainfall across the year, litter responses to these conditions will affect both nutrient and carbon cycles. More detailed inter- and intra-site analysis is needed to elucidate the mechanisms underlying the relationship between rainfall patterns and litter production.

Session:  Biogeochemistry - Nutrient cycling in forest and savanna ecosystems and agroecosystems.

Presentation Type:  Poster