Spatial distribution of life‐history traits and their response to environmental gradients across multiple marine taxa

Laurene Pecuchet,Martin Lindegren,P Daniel Van Denderen,Gabriel Reygondeau,William W L Cheung,Priscilla Licandro,Mark R Payne

doi:10.1002/ecs2.2460

Abstract

AbstractTrait‐based approaches enable comparison of community composition across multiple organism groups. Yet, little is known about the degree to which empirical trait responses found for one taxonomic group can be generalized across organisms. In this study, we investigated the spatial variability of marine community‐weighted mean traits and compared their environmental responses across multiple taxa and habitats, including pelagic zooplankton (copepods), demersal fish, and benthic infaunal invertebrates. We used extensive, spatially explicit datasets collected from scientific surveys in the North Sea and examined community composition of these groups using a trait‐based approach. In order to cover the key biological characteristics of an organism, we considered three life‐history traits (adult size, offspring size, and fecundity) and taxon‐specific feeding traits. While many of the traits co‐varied in space and notably demonstrated a south–north gradient, none of the traits showed a consistent spatial distribution across all groups. However, traits are often correlated as a result of trade‐offs. When studying spatial patterns of multiple traits variability in fish and copepods, we showed a high spatial correlation. This also applied to a lesser extent to fish and benthic infauna, whereas no correlation was found between benthic infauna and copepods. The result suggested a decoupling in the community traits between strictly benthic and strictly pelagic species. The strongest drivers of spatial variability for many community traits are the gradients in temperature seasonality, primary productivity, fishing effort, and depth. Spatial variability in benthic traits also co‐varied with descriptors of the seabed habitat. Overall, results showed that trait responses to environmental gradients cannot be generalized across organism groups, pointing toward potential complex responses of multi‐taxa communities to environmental changes and highlighting the need for cross‐habitat multi‐trait analyses to foresee how environmental change will affect community structure and biodiversity at large.

Highlights

Characterizing species by their key traits allows understanding the mechanisms behind community assembly and the processes influencing species presence in communities (Kraft et al 2008, Weiher et al 2011, Pecuchet et al 2016)
Offspring size displays different patterns across the groups; it is higher in the central North Sea for fish, while it is higher in the north for copepods and in the western region for the benthic infauna
The spatial patterns observed for copepod and fish community-weighted mean (CWM) traits in the late 1980s remain largely similar through time, as shown by recent maps calculated for the years 2005–2010 (Appendix S1: Fig. S3)

Summary

Introduction

Characterizing species by their key traits (e.g., body size) allows understanding the mechanisms behind community assembly and the processes influencing species presence in communities (Kraft et al 2008, Weiher et al 2011, Pecuchet et al 2016). Life-history traits are often related through trade-offs that define the life-history strategy of a given organism (Winemiller et al 2015). Such life-history strategies are used to shed light on the evolution of organisms, as well as the environment in which the species occur (Charnov et al 2013). Two well-known examples of lifehistory theories or models to explain life-history strategies are r- vs K-selected species (Pianka 1970) and the competition–stress–disturbance vegetation classification (Grime 1974), while more recently for fish communities, Winemiller and Rose (1992) developed the equilibrium– periodic–opportunistic model which links three strategies through trade-offs between fecundity, juvenile survival, and generation time. Some traits and trade-offs are unique for a particular group of organisms, while others, termed lifehistory invariants, can be used to compare across taxa (Charnov 1993)

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Conclusion