Decomposition and diversity in streams globally (DecoDiv) – 2016
Funding: Basque Government (coordination), crowdfunding (field and lab work)
A key question in contemporary ecology is how the loss of biological diversity affects ecosystem functioning. Plant litter decomposition is a fundamental ecosystem process with major consequences for the carbon cycle, but it is unclear how the loss of plant diversity affects decomposition rates. In a global-scale stream study, Boyero et al. (2016 Proc R Soc B 283: 20152664) examined decomposition rates of litter mixtures differing in phylogenetic diversity across latitudes and found that more diverse mixtures decomposed faster in the tropics, while less diverse mixtures decomposed faster at high latitudes. This suggested that different mechanisms might operate at different latitudes, possibly in relation to differences in biological assemblages that break down plant litter. Here, we explored this question through a coordinated experiment conducted at 40 stream sites distributed globally, where we quantified the decomposition of litter mixtures differing in phylogenetic diversity (low vs. high) and examined how differences between the decomposition of both litter mixture types varied across latitudes.
Variation in leaf litter quality across latitudes – 2013
Funding: Doñana Biological Station-CSIC (coordination), MARE-Unversity of Coimbra (chemical analyses), crowdfunding (field work)
Plant litter represents a major basal resource in streams, where its decomposition is partly regulated by litter traits. However, we lack information on large-scale trait variation for riparian litter. Here, we performed the first global-scale assessment of riparian major litter traits (nutrients, physical structure and chemical defenses), including 151 species from 24 regions spanning a 107º latitudinal gradient. We also explored the relationships between trait variation, environmental factors and plant phylogeny.
Global-scale variation in decomposition rates and detritivore assemblages – 2006
Funding: National Geographic Committee for Research and Exploration (coordination, field and lab work), crowdfunding (field and lab work)
Biological diversity is often maximum in tropical regions, with a steady decline towards the poles. However, stream detritivores seem to be scarcer in the tropics, with potential repercussions for stream ecosystem functioning at these latitudes. Here, we explored patterns of detritivore diversity at 156 sites globally distributed across a 108º latitudinal gradient. We also explored variation in decomposition rates of a standard substrate (black alder litter) and local 3-species litter mixtures at 24 sites distributed across a 91º latitudinal gradient.