Changes in the location of biodiversity–ecosystem function hot spots across the seafloor landscape with increasing sediment nutrient loading

Abstract

Declining biodiversity and loss of ecosystem function threatens the ability of habitats to contribute ecosystem services. However, the form of the relationship between biodiversity and ecosystem function (BEF) and how relationships change with environmental change is poorly understood. This limits our ability to predict the consequences of biodiversity loss on ecosystem function, particularly in real-world marine ecosystems that are species rich, and where multiple ecosystem functions are represented by multiple indicators. We investigated spatial variation in BEF relationships across a 300 000 m 2 intertidal sandflat by nesting experimental manipulations of sediment pore water nitrogen concentration into sites with contrasting macrobenthic community composition. Our results highlight the significance of many different elements of biodiversity associated with environmental characteristics, community structure, functional diversity, ecological traits or particular species (ecosystem engineers) to important functions of coastal marine sediments (benthic oxygen consumption, ammonium pore water concentrations and flux across the sediment-water interface). Using the BEF relationships developed from our experiment, we demonstrate patchiness across a landscape in functional performance and the potential for changes in the location of functional hot and cold spots with increasing nutrient loading that have important implications for mapping and predicating change in functionality and the concomitant delivery of ecosystem services.

Linking changes in species–trait relationships and ecosystem function using a network analysis of traits

“…To test NAT, we use the data derived from a field experiment that manipulated sediment nitrogen concentration by Thrush et al. (). The experiment demonstrated the importance of different biodiversity indicators and habitat characteristics in predicting changes to selected ecosystem functions under the varying nitrogen concentrations in intertidal sandflats of New Zealand.…”

“…The Thrush et al. () experiment was conducted in Tapora Bank, Kaipara Harbour (36°39′ S, 174°29′ E), New Zealand. The site (300,000 m 2 ) was first extensively and systematically surveyed (400 macrofaunal cores) to encompass natural macrofaunal patterns and assure consistency of the macrofauna community within selected locations of the experiment (see Thrush et al.…”

“…, Thrush et al. ). Further, most of the available functional diversity indices are limited in providing an explicit and transparent analysis of ecological communities as networks, e.g., the analysis of structural changes in functional clusters and changes in between and within clusters connectivity based on the links between the nodes.…”

“…This experiment (Thrush et al. ) provides a valuable test of NAT because of the extensive and diverse community data and the mechanistic links to how the community affects nitrogen processing in marine sediments. Increased nitrogen input from land is a significant management challenge affecting coastlines worldwide (Valiela et al.…”

The role of large macrofauna in mediating sediment erodibility across sedimentary habitats

“…3 cm). where A i is the abundance of a species/taxon i in a sample. Trait scores were derived from expert knowledge ( see Hewitt et al ; Thrush et al ), and are listed in Supplementary Information S1.…”