Plant litter represents a major basal resource in streams, where its decomposition is partly regulated by
litter traits. Litter-trait variation may determine the latitudinal gradient in decomposition in streams,
which is mainly microbial in the tropics and detritivore-mediated at high latitudes. However, this
hypothesis remains untested, as we lack information on large-scale trait variation for riparian litter.
Variation cannot easily be inferred from existing leaf-trait databases, since nutrient resorption can
cause traits of litter and green leaves to diverge. Here we present the first global-scale assessment
of riparian litter quality by determining latitudinal variation (spanning 107°) in litter traits (nutrientPeer reviewe
