Marine biodiversity and ecosystem functioning: what’s known and what’s next?

Abstract

Marine ecosystems are experiencing rapid and pervasive loss of species.Understanding the consequences of species loss is critical to effectively managing these systems. Over the last several years, numerous experimental manipulations of 25 species richness have been performed, yet existing quantitative syntheses have focused on a just a subset of processes measured in experiments and, as such, have not summarized the full data available from marine systems. Here, we present the results of a meta-analysis of 174 marine experiments from 42 studies that have manipulated the species richness of organisms across a range of taxa and trophic 30 levels and analysed the consequences for various ecosystem processes (categorised as production, consumption or biogeochemical fluxes).Our results show that, generally, mixtures of species tend to enhance levels of ecosystem function relative to the average component species in monoculture, but have no or negative effect on functioning relative to the 'highest-performing' species. 35These results are largely consistent with those from other syntheses, and extend conclusions to ecological functions that are most commonly measured in the marine realm (e.g. nutrient release from sediment bioturbation). For experiments that manipulated three or more levels of richness, we attempted to discern the functional form of the BEF relationship. We found that, for response variables categorised as 40 consumption, a power-function best described the relationship, which is also consistent with previous findings. However, we identified a linear relationship between richness and production. Combined, our results suggest that losses of species will, on average, tend to alter the functioning of marine ecosystems. We outline several research frontiers that will allow us to more fully understand how, why, and 45 when diversity may drive the functioning of marine ecosystems.

Low redundancy and complementarity shape ecosystem functioning in a low‐diversity ecosystem

“…Low functional redundancy has been widely reported from animal assemblages in marine ecosystems, for example, on coral reefs (Brandl & Bellwood, ; D'agata et al, ), in kelp forests (Ling et al, ; Micheli & Halpern, ) and over seagrass meadows (Duffy et al, ; Reynolds et al, ). This is, however, the first time that both low redundancy and low complementarity may have been reported for animal assemblages and ecological functions in coastal seascapes (Gamfeldt et al, ). Our findings demonstrate that ecological functions may still be maintained across estuarine seascapes despite no influence of biodiversity, resulting in limited redundancy and complementarity in the functional traits of animal assemblages.…”

European seaweeds under pressure: Consequences for communities and ecosystem functioning

“…In a recent meta-analysis of marine studies, Gamfeldt et al (2014) unambiguously illustrated that losing species will cause general reductions in ecosystem functions on average (see also Stachowicz et al 2007, Worm et al 2006). However, extrapolating results from experiments to real-world is not always straightforward and in the case of seaweeds the extent of primary productivity reduction associated with the current changes on diversity is uncertain.…”

Impact of multiple disturbances and stress on the temporal trajectories and resilience of benthic intertidal communities

“…These various changes can have drastic negative effects on ecosystems, such as biodiversity loss, that impact community functioning and stability (Stachowicz et al 2002, Lotze et al 2006, Hooper et al 2012. Climate change and biodiversity loss are driving ecologists to study the relationship between biodiversity and ecosystem functioning , Gamfeldt et al 2015.…”