Leaf litter decomposition in six Cloud Forest streams of the upper La Antigua watershed, Veracruz, Mexico.

Leaf litter decomposition is an important stream ecosystem process. To understand factors controlling leaf decomposition in cloud forest in Mexico, we incubated leaf packs in different streams along a land use cover gradient for 35 days during the dry and wet seasons. We assessed relations between leaf decomposition rates (k), stream physicochemistry, and macroinvertebrates colonizing leaf packs. Physicochemical parameters showed a clear seasonal difference at all study streams. Leaves were colonized by collector-gatherer insects, followed by shredders. Assessment of factors related to k indicated that only forest cover was negatively related to leaf decomposition rates. Thus stream physicochemistry and seasonality had no impact on decomposition rates. We concluded that leaf litter decomposition at our study streams is a stable process over the year. However, it is possible that this stability is the result of factors regulating decomposition during the different seasons and streams.