Litter chemistry and chemical diversity drive ecosystem processes in forest ponds

Abstract

Research suggests that a positive relationship exists between diversity and ecological function, yet the multi-trophic effects of biodiversity remain poorly understood. The resource complementarity hypothesis suggests that increasing the trait diversity of resources provides a more complete diet for consumers, elevating consumer feeding rates. Whereas previous tests of this mechanism have measured trait diversity as the variation of single traits or the richness of functional groups, we employed a multivariate trait index to manipulate the chemical diversity of temperate tree litter species in outdoor pond mesocosms. We inoculated outdoor mesocosms with diverse and multi-trophic communities of microbial and macro-consumer species that rely on leaf litter for energy and nutrients. Litter was provided at three levels of chemical trait diversity, a constant level of species richness, and an equal representation of all litter species. Over three months, we measured more than 65 responses, and assessed the effects of litter chemical diversity and chemical trait means (i.e., community-weighted means). We found that litter chemical diversity positively correlated with decomposition rate of leaf litter, but had no effect on biomass or density of producers and consumers. However, the pond communities often responded to chemical trait means, particularly those related to nutrients, structure, and defense. Our results suggest that resource complementarity does have some effect on the release of energy and nutrients from decomposing substrates in forest ponds, but does not have multi-trophic effects. Our results further suggest that loss of tree biodiversity could affect forest ecosystem functionality, and particularly the processes occurring in and around ponds and wetlands.

Leaf litter traits drive community structure and functioning in a natural aquatic microcosm

“…Although several studies have evaluated the effects of litter composition on aquatic systems, to date few have directly tested which litter traits are the most important drivers of detritivore community structure and decomposition (Rubbo & Kiesecker, ; Stoler, Burke, & Relyea, ; Stoler & Relyea, ; Yanoviak, ). Here, we investigated the effects of leaf litter composition, contrasting the explanatory power of litter richness (i.e.…”

“…Although several studies have evaluated the effects of litter composition on aquatic systems, to date few have directly tested which litter traits are the most important drivers of detritivore community structure and decomposition (Rubbo & Kiesecker, 2004;Stoler, Burke, & Relyea, 2016;Yanoviak, 1999).…”

Hydrological gradients and functional diversity of plants drive ecosystem processes inPoyang Lakewetland

“…That is, the more different functional strategies of niches co-occurred within a community, the more complete use of resources in space or time, which enhancing ecosystem functioning. To date, all the three hypotheses have been shown to be good predictors of ecosystem functioning in terrestrial (Cardinale et al, 2007;Mokany et al, 2008); aquatic (Fu et al, 2014;Stoler, Burke, & Relyea, 2016;Zwart, Solomon, & Jones, 2015); and wetland ecosystems (Minden & Kleyer, 2015;Purcell, 2016). Due to the highly dimensionality and complexity of natural ecosystem, the particular function of ecosystem might not be explained simply either by a single factor or a kind of diversity indices (Roscher et al, 2013).…”

Reviewing the role of plant litter inputs to forested wetland ecosystems: leafing through the literature

“…provide few resources for microbes and detritivores, although the lack of soluble leachates can also increase light availability and algal growth (Stoler et al. ). In contrast, litter species with moderate decay rates (i.e., containing moderate amounts of structural compounds; e.g., Acer spp., Ulmus spp.)…”