Modelling trophic flows in ecosystems to assess the efficiency of marine protected area (MPA), a case study on the coast of Sénégal

Colléter, Mathieu; Gascuel, Didier; Écoutin, Jean-Marc; Morais, Luis Tito de

doi:10.1016/j.ecolmodel.2012.01.019

Cited by 46 publications

(31 citation statements)

References 49 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Trophic spectra have been used to test the impact of management measures on ecosystems (e.g. Colléter et al 2012, Valls et al 2012, and to quantify the effects of exploitation on trophic structure both in theoretical studies (Gascuel & Pauly 2009) and for specific case studies (Guinea, Gascuel et al 2011;Benguela, Gasche et al 2012; Bay of Biscay, Lassalle et al 2012). …”

Section: Data Used To Calculate Trophic Level-based Indicatorsmentioning

confidence: 99%

Trophic level-based indicators to track fishing impacts across marine ecosystems

Shannon¹,

Coll²,

Bundy³

et al. 2014

Mar. Ecol. Prog. Ser.

135

View full text Add to dashboard Cite

Trophic level (TL)-based indicators have been widely used to examine fishing impacts in aquatic ecosystems and the induced biodiversity changes. However, much debate has ensued regarding discrepancies and challenges arising from the use of landings data from commercial fisheries to calculate TL indicators. Subsequent studies have started to examine survey-based and model-based indicators. In this paper, we undertake an extensive evaluation of a variety of TL indicators across 9 well-studied marine ecosystems by making use of model-as well as surveyand catch-based TL indicators. Using detailed regional information and data on fishing history, fishing intensity, and environmental conditions, we evaluate how well TL indicators are capturing fishing effects at the community level of marine ecosystems. Our results highlight that the differences observed between TL indicator values and trends is dependent on the data source and the TL cut-off point used in the calculations and is not attributable to an intrinsic problem with TLbased indicators. All 3 data sources provide useful information about the structural changes in the ecosystem as a result of fishing, but our results indicate that only model-based indicators represent fishing impacts at the whole ecosystem level.

show abstract

Section: Data Used To Calculate Trophic Level-based Indicatorsmentioning

confidence: 99%

Trophic level-based indicators to track fishing impacts across marine ecosystems

Shannon¹,

Coll²,

Bundy³

et al. 2014

Mar. Ecol. Prog. Ser.

135

View full text Add to dashboard Cite

show abstract

“…Similar hypothesis had been suggested by many other authors. Colléter, Gascuel, Ecoutin, and Tito de Morais (2012), for example, have found a 2.5 fold increase in predatory fish biomass, while that of their prey decreased by a factor of 1.7. They attempted to link these modifications mainly to environmental effects combined to other factors as the predation pressure reinforced by the probable occurrence of cascading mechanism and the variability in the recruitment of forage fish, in particular, E. fimbriata.…”

Section: Total Biomass Evolutionmentioning

confidence: 99%

Assessment of the Recovering Effects of Protected Areas Using a Multiple Functional Approaches: The Bamboung Model (Senegal, West Africa)

Faye¹

2015

IJB

View full text Add to dashboard Cite

The Bamboung protected area (Senegal, West Africa) has been implemented in 2003. However, little is known about its recovering effects on fish assemblage functional diversity. To address this issue, a morphology-based functional grouping was adopted, and results were compared to prior classifications. Functional richness relative to each guild and species abundance was used to define a functional redundancy index. Morphometric measurements were done in the field on freshly killed specimens and completed by digital image processing using the Image-J software in laboratory. Data relative to biomass and abundance were obtained from the IRD (Research Institute for Development) / Adaptive Response of Fish Assemblages to the Environmental Pressure (RAP) Unit-Research database. Hierarchical clustering, analysis using the ward method, was applied to the matrix of morphological traits to discriminate fish assemblages into four functional guilds: zoobenthos feeders, algivorous / detritivorous fish, benthopelagic fish, and demersal and ichthyophagous fish. The new functional grouping reduced fish assemblage complexity to smaller and more significant units than those obtained from previous gut-content based-classification, and the modifications affecting fish biomass distribution after fishing ban, marked by large predatory fishes domination appeared more perceptible. Classification based on fish life-history traits showed similar results with a domination of fish assemblages by marine species of larger size and upper trophic level. However, this latter approach is still relevant as it provides significant information on fish species mobility and community dynamics. Major observed changes occurred after one to three years of protection. The total fish biomass varied from 6458 kg.km -2 in 2003 to 3114 kg.km -2 in 2007. We hypothesized that collapse in total fish biomass may be explained by predation pressure in the system. Species richness varied from 51 in 2003 to 72 in 2007, while the functional redundancy index showed a decreasing trend indicating a functional diversification in the system subsequent to the reserve establishment. The present study highlights the relevance of multiple approaches model in addressing dynamics of complex systems. However, the present trend does not presage the future evolution in the system, many reserves take over a decade to get a stable state.

show abstract

“…More particularly, given the important biomass of decapods and their con nections with higher TLs, their inclusion in the Epifauna group significantly altered the biomass trophic spectrum, impacting the distribution of biomass up to higher TLs and causing a general decrease in the mean TL of the community. Trophic spectra are now recognized as a useful tool with which to analyse the impacts of fisheries and/or protection on the whole trophic network , Libralato et al 2010, Colléter et al 2012, Lassalle et al 2012), but if they are initially altered by a biased model structure, in accurate conclusions could be derived from their observation. The inclusion of polychaetes and suspensivores in the Epifauna group should be avoided, although it would simplify sampling.…”

Section: Aggregating Trophic Groupsmentioning

confidence: 99%

“…EcoTroph, a trophodynamic model recently integrated as a plug-in in the EwE software (Gascuel 2005, 2011, is based on the idea that an ecosystem can be represented by the distribution of its biomass across trophic levels (TLs), called the biomass trophic spectrum. The simplified picture of ecosystem functioning provided by EcoTroph has proven to be very useful for exploring theoretical aspects of ecosystems, as well as for analysing the impacts of fishing or protection (Colléter et al 2012, Gasche & Gascuel 2013.…”

Section: Introductionmentioning

confidence: 99%

Balancing complexity and feasibility in Mediterranean coastal food-web models: uncertainty and constraints

Prato¹,

Gascuel²,

Valls³

et al. 2014

Mar. Ecol. Prog. Ser.

View full text Add to dashboard Cite

Mass-balance trophic models (Ecopath and EcoTroph) are valuable tools that can be used to describe ecosystem structure and functioning, identify target species to be monitored, and allow comparisons of ecosystem states under different management options. Nevertheless, the Ecopath modelling approach is constrained by 2 major sources of uncertainty: model complexity and input data quality. We developed an approach for identifying the optimum model structure that considers trade-offs between feasibility, complexity, and uncertainty, using a Mediterranean coastal ecosystem as a case study. We began with an existing well-documented and good-quality food-web model comprising 41 functional groups at Port-Cros National Park, France. Based on this model, we assessed the effects of different aggregation choices, driven by a simplification of sampling effort, on the Ecopath and EcoTroph model outputs. We identified the functional groups in which imprecise biomass input significantly influenced the food-web model, and measured the relative effects on the ecosystem trophic structure and ecosystem maturity and complexity indices. A simplified model comprising 32 functional groups was identified as the best compromise between model complexity and reliability. High trophic level predators, abundant primary producers, and groups with a high biomass and/or diversified diet significantly influenced the model structure. We concluded that the collection of local and accurate biomass data, especially for the most influential functional groups we identified, should be a priority when developing food-web models for similar ecosystems. Our method enables simplified and standardized models, while considering both the feasibility and reliability of the Ecopath and EcoTroph applications for Mediterranean coastal ecosystems.

show abstract

Modelling trophic flows in ecosystems to assess the efficiency of marine protected area (MPA), a case study on the coast of Sénégal

Cited by 46 publications

References 49 publications

Trophic level-based indicators to track fishing impacts across marine ecosystems

Trophic level-based indicators to track fishing impacts across marine ecosystems

Assessment of the Recovering Effects of Protected Areas Using a Multiple Functional Approaches: The Bamboung Model (Senegal, West Africa)

Balancing complexity and feasibility in Mediterranean coastal food-web models: uncertainty and constraints

Contact Info

Product

Resources

About