Faculty Opinions recommendation of The meaning of functional trait composition of food webs for ecosystem functioning.

2017 ◽  
Author(s):  
Oswald Schmitz
Keyword(s):  
Food Webs ◽  
Ecosystem Functioning ◽  
Functional Trait

scholarly journals The meaning of functional trait composition of food webs for ecosystem functioning

2016 ◽  
Vol 371 (1694) ◽  
pp. 20150268 ◽  
Author(s):  
Dominique Gravel ◽  
Camille Albouy ◽  
Wilfried Thuiller
Keyword(s):  
Food Web ◽  
Food Webs ◽  
Functional Diversity ◽  
Ecosystem Functioning ◽  
Functional Trait ◽  
Plant Ecology ◽  
Functional Composition ◽  
Top Down ◽  
Bottom Up ◽  
Functional Trait Diversity

There is a growing interest in using trait-based approaches to characterize the functional structure of animal communities. Quantitative methods have been derived mostly for plant ecology, but it is now common to characterize the functional composition of various systems such as soils, coral reefs, pelagic food webs or terrestrial vertebrate communities. With the ever-increasing availability of distribution and trait data, a quantitative method to represent the different roles of animals in a community promise to find generalities that will facilitate cross-system comparisons. There is, however, currently no theory relating the functional composition of food webs to their dynamics and properties. The intuitive interpretation that more functional diversity leads to higher resource exploitation and better ecosystem functioning was brought from plant ecology and does not apply readily to food webs. Here we appraise whether there are interpretable metrics to describe the functional composition of food webs that could foster a better understanding of their structure and functioning. We first distinguish the various roles that traits have on food web topology, resource extraction (bottom-up effects), trophic regulation (top-down effects), and the ability to keep energy and materials within the community. We then discuss positive effects of functional trait diversity on food webs, such as niche construction and bottom-up effects. We follow with a discussion on the negative effects of functional diversity, such as enhanced competition (both exploitation and apparent) and top-down control. Our review reveals that most of our current understanding of the impact of functional trait diversity on food web properties and functioning comes from an over-simplistic representation of network structure with well-defined levels. We, therefore, conclude with propositions for new research avenues for both theoreticians and empiricists.

scholarly journals Reducing the Eltonian shortfall with trophic interaction models

2021 ◽  
Author(s):  
Dominique Caron ◽  
Luigi Maiorano ◽  
Wilfried Thuiller ◽  
Laura J. Pollock
Keyword(s):  
Food Web ◽  
Food Webs ◽  
Functional Traits ◽  
Conservation Planning ◽  
Ecosystem Functioning ◽  
Species Interactions ◽  
Large Scale ◽  
Spatial Scales ◽  
Functional Trait ◽  
Predator Prey

While species interactions are fundamental for linking biodiversity to ecosystem functioning and for conservation, large-scale empirical data are lacking for most species and ecosystems. Accumulating evidence suggests that trophic interactions are predictable from available functional trait information, but we have yet to understand how well we can predict interactions across large spatial scales and food webs. Here, we built a model predicting predator-prey interactions based on functional traits for European vertebrates. We found that even models calibrated with very few known interactions (100 out of 71k) estimated the entire food web reasonably well. However, predators were easier to predict than prey, with prey in some clades being particularly difficult to predict (e.g., fowls and storks). Local food web connectance was also consistently over-estimated. Our results demonstrate the potential for filling gaps in sparse food webs, an important step towards a better description of biodiversity with strong implications for conservation planning.

scholarly journals Functional trait responses to sediment deposition reduce macrofauna-mediated ecosystem functioning in an estuarine mudflat

2018 ◽  
Vol 15 (9) ◽  
pp. 2587-2599 ◽  
Author(s):  
Sebastiaan Mestdagh ◽  
Leila Bagaço ◽  
Ulrike Braeckman ◽  
Tom Ysebaert ◽  
Bart De Smet ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
Ecosystem Functioning ◽  
River Estuary ◽  
Functional Trait ◽  
Sediment Deposition ◽  
Sediment Chemistry ◽  
Sediment Layer ◽  
Sediment Reworking ◽  
Macrobenthic Communities ◽  
The Impact

Abstract. Human activities, among which dredging and land use change in river basins, are altering estuarine ecosystems. These activities may result in changes in sedimentary processes, affecting biodiversity of sediment macrofauna. As macrofauna controls sediment chemistry and fluxes of energy and matter between water column and sediment, changes in the structure of macrobenthic communities could affect the functioning of an entire ecosystem. We assessed the impact of sediment deposition on intertidal macrobenthic communities and on rates of an important ecosystem function, i.e. sediment community oxygen consumption (SCOC). An experiment was performed with undisturbed sediment samples from the Scheldt river estuary (SW Netherlands). The samples were subjected to four sedimentation regimes: one control and three with a deposited sediment layer of 1, 2 or 5 cm. Oxygen consumption was measured during incubation at ambient temperature. Luminophores applied at the surface, and a seawater–bromide mixture, served as tracers for bioturbation and bio-irrigation, respectively. After incubation, the macrofauna was extracted, identified, and counted and then classified into functional groups based on motility and sediment reworking capacity. Total macrofaunal densities dropped already under the thinnest deposits. The most affected fauna were surficial and low-motility animals, occurring at high densities in the control. Their mortality resulted in a drop in SCOC, which decreased steadily with increasing deposit thickness, while bio-irrigation and bioturbation activity showed increases in the lower sediment deposition regimes but decreases in the more extreme treatments. The initial increased activity likely counteracted the effects of the drop in low-motility, surficial fauna densities, resulting in a steady rather than sudden fall in oxygen consumption. We conclude that the functional identity in terms of motility and sediment reworking can be crucial in our understanding of the regulation of ecosystem functioning and the impact of habitat alterations such as sediment deposition.

scholarly journals Is the use of unconstrained ordination appropriate for understanding plant ecological strategies and ecosystem functioning?

2017 ◽  
Author(s):  
Linhai Zhu ◽  
Jonathan S Lefcheck ◽  
Bojie Fu
Keyword(s):  
Functional Traits ◽  
Ecosystem Functioning ◽  
Functional Trait ◽  
Alternative Methods ◽  
Ecosystem Ecology ◽  
Ecological Strategies ◽  
Mechanistic Insight ◽  
Definition Of ◽  
Plant Ecological ◽  
Insight Into

The use of functional traits has increased exponentially in ecology, particularly in attempting to understand plant strategies and ecosystem functioning. This popularity has led to many proposed definitions of functional traits, which in turn has informed recommendations about how to gather, summarize, and analyze trait data. In this paper, we revisit the definition of the functional trait from the perspective of physiological, community and ecosystem ecology, and reason towards a broad, unrestrictive, and applicable definition. We then outline the conceptual mismatch between this definition and the popular practice of summarizing trait information using unconstrained ordination . We make specific suggestions about alternative methods to gain a mechanistic insight into how traits translate into functions. We hope this paper will improve our ability to move towards an ecological synthesis using a trait-based approach.

scholarly journals Multitrophic functional diversity predicts ecosystem functioning in experimental assemblages of estuarine consumers

2015 ◽  
Author(s):  
Jonathan S Lefcheck ◽  
J. Emmett Duffy
Keyword(s):  
Species Richness ◽  
Food Web ◽  
Functional Diversity ◽  
Ecosystem Functioning ◽  
Structural Equation ◽  
A Priori ◽  
Functional Trait ◽  
Trophic Levels ◽  
Equation Modeling ◽  
Experimental Investigations

The use of functional traits to explain how biodiversity affects ecosystem functioning has attracted intense interest, yet few studies have a priori altered functional diversity, especially in multitrophic communities. Here, we manipulated multivariate functional diversity of estuarine grazers and predators within multiple levels of species richness to test how species richness and functional diversity predicted ecosystem functioning in a multitrophic food web. Community functional diversity was a better predictor than species richness for the majority of ecosystem properties, based on general linear mixed effects models. Combining inferences from 8 traits into a single multivariate index increased prediction accuracy of these models relative to any individual trait. Structural equation modeling revealed that functional diversity of both grazers and predators was important in driving final biomass within trophic levels, with stronger effects observed for predators. We also show that different species drove different ecosystem responses, with evidence for both sampling effects and complementarity. Our study extends experimental investigations of functional trait diversity to a multilevel food web, and demonstrates that functional diversity can be more accurate and effective than species richness in predicting community biomass in a food web context.

scholarly journals Multitrophic functional diversity predicts ecosystem functioning in experimental assemblages of estuarine consumers

2015 ◽  
Author(s):  
Jonathan S Lefcheck ◽  
J. Emmett Duffy
Keyword(s):  
Species Richness ◽  
Food Web ◽  
Functional Diversity ◽  
Ecosystem Functioning ◽  
Structural Equation ◽  
A Priori ◽  
Functional Trait ◽  
Trophic Levels ◽  
Equation Modeling ◽  
Experimental Investigations

The use of functional traits to explain how biodiversity affects ecosystem functioning has attracted intense interest, yet few studies have a priori manipulated functional diversity, especially in multitrophic communities. Here, we manipulated multivariate functional diversity of estuarine grazers and predators within two levels of species richness to test how species richness and functional diversity predicted ecosystem functioning in a multitrophic food web. Community functional diversity was a better predictor than species richness for the majority of ecosystem properties, based on general linear mixed effects models. Combining inferences from 8 traits into a single multivariate index increased prediction accuracy of these properties relative to any individual trait. Structural equation modeling revealed that functional diversity of both grazers and predators was important in driving final biomass within and between trophic levels, with stronger effects observed for predators. We also show that different species drove different ecosystem responses, with evidence for both sampling effects and complementarity. Our study extends experimental investigations of functional trait diversity to a multilevel food web, and demonstrates that functional diversity can be more accurate and effective than species richness in predicting community biomass in a food web context.

scholarly journals fluxweb: a R package to easily estimate energy fluxes in food webs

2017 ◽  
Author(s):  
Benoit Gauzens ◽  
Andrew Barnes ◽  
Darren Giling ◽  
Jes Hines ◽  
Malte Jochum ◽  
...  
Keyword(s):  
Steady State ◽  
Food Web ◽  
Food Webs ◽  
Ecosystem Functioning ◽  
R Package ◽  
Estimation Methods ◽  
List Type ◽  
Energy Fluxes ◽  
Flux System ◽  
Primary Output

AbstractUnderstanding how changes in biodiversity will impact the stability and functioning of ecosystems is a central challenge in ecology. Food-web approaches have been advocated to link community composition with ecosystem functioning by describing the fluxes of energy among species or trophic groups. However, estimating such fluxes remains problematic because current methods become unmanageable as network complexity increases.We developed a generalisation of previous indirect estimation methods assuming a steady state system [1, 2, 3]: the model estimates energy fluxes in a top-down manner assuming system equilibrium; each node’s losses (consumption and physiological) balances its consumptive gains. Jointly, we provide theoretical and practical guidelines to use the fluxweb R package (available on CRAN at https://bit.ly/2OC0uKF).We also present how the framework can merge with the allometric theory of ecology [4] to calculate fluxes based on easily obtainable organism-level data (i.e. body masses and species groups -eg, plants animals), opening its use to food webs of all complexities. Physiological losses (metabolic losses or losses due to death other than from predation within the food web) may be directly measured or estimated using allometric relationships based on the metabolic theory of ecology, and losses and gains due to predation are a function of ecological efficiencies that describe the proportion of energy that is used for biomass production.The primary output is a matrix of fluxes among the nodes of the food web. These fluxes can be used to describe the role of a species, a function of interest (e.g. predation; total fluxes to predators), multiple functions, or total energy flux (system throughflow or multitrophic functioning). Additionally, the package includes functions to calculate network stability based on the Jacobian matrix, providing insight into how resilient the network is to small perturbations at steady state.Overall, fluxweb provides a flexible set of functions that greatly increase the feasibility of implementing food-web energetic approaches to more complex systems. As such, the package facilitates novel opportunities for mechanistically linking quantitative food webs and ecosystem functioning in real and dynamic natural landscapes.

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