Evaluation of quantitative indicators for marine fish communities

Methratta, Elizabeth T.; Link, Jason S.

doi:10.1016/j.ecolind.2005.08.022

Cited by 79 publications

(64 citation statements)

References 42 publications

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“…Structural: community structure, and energy flow Methratta and Link, 2006 Planktivore and benthivore to shrimp and fish eater ratio LHTR Ratio of the biomass of low trophic level to high trophic level fishes Functional: trophic dynamics, energy flow Link et al, 2002;Methratta and Link, 2006;Smith and Link, 2010 Mean trophic level MTL Mean trophic level of surveyed species weighted by abundance (biomass)…”

Section: Gradient Forest Analysismentioning

confidence: 99%

“…In contrast to these past studies, this particular analysis focused on cross-ecosystem comparisons and only included ecological indicators that were transferrable across the differing LMEs into the analysis. Inclusion of LME-specific ecological indicators (e.g., longhorn sculpin in the Northeast US; Methratta and Link, 2006) improved the variance explained, but would not allow for true cross-ecosystem comparisons, thus they were excluded from this particular study and account for the lower overall variance explained. Additionally, and more to the point in this comparative study, although the variance explained may be low, multiple (but very different) statistical analyses yielded similar threshold points both within and across ecosystems.…”

Section: Model Performancementioning

confidence: 99%

“…The fishery-independent monitoring program uses a depth stratified survey design run semiannually (spring and autumn in the Northeast US; summer and autumn in the Gulf of Mexico; Reid et al, 1999;Nichols, 2004;Politis et al, 2014;Pollack et al, 2016) and annually (summer in Alaska and the California Current; Levin and Schwing, 2011;Conner and Lauth, 2017). Calculated from these survey data, we chose a suite of six ecological indicators that have been vetted and found to met international standards of useful indicators for assessing ecosystem status (Garrison, 2000;Methratta and Link, 2006;Fay et al, 2013Fay et al, , 2015. The suite of ecological indicators represented a variety of ecosystem attributes (functional, structural, and resilience aspects of marine ecosystems) and were also chosen for universal applicability and the ability to translate across the various ecosystems examined ( Table 1).…”

Section: Ecological Indicatorsmentioning

confidence: 99%

“…Functional: how energy flow within an ecosystem is processed Methratta and Link, 2006;Smith and Link, 2010 Species richness Rich Number of species surveyed Resilience: community status, biodiversity Downing and Leibold, 2010 Diversity (Effective number) EN Exponent of Shannon diversity index. Measure of species diversity.…”

Section: Gradient Forest Analysismentioning

confidence: 99%

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Comparing Apples to Oranges: Common Trends and Thresholds in Anthropogenic and Environmental Pressures across Multiple Marine Ecosystems

et al. 2017

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Ecosystem-based management (EBM) in marine ecosystems considers impacts caused by complex interactions between environmental and anthropogenic pressures (i.e., oceanographic, climatic, socio-economic) and marine communities. EBM depends, in part, on ecological indicators that facilitate understanding of inherent properties and the dynamics of pressures within marine communities. Thresholds of ecological indicators delineate ecosystem status because they represent points at which a small increase in one or many pressure variables results in an abrupt change of ecosystem responses. The difficulty in developing appropriate thresholds and reference points for EBM lies in the multidimensionality of both the ecosystem responses and the pressures impacting the ecosystem. Here, we develop thresholds using gradient forest for a suite of ecological indicators in response to multiple pressures that convey ecosystem status for large marine ecosystems from the US Pacific, Atlantic, sub-Arctic, and Gulf of Mexico. We detected these thresholds of ecological indicators based on multiple pressures. Commercial fisheries landings above approximately 2-4.5 t km −2 and fisheries exploitation above 20-40% of the total estimated biomass (of invertebrates and fish) of the ecosystem resulted in a change in the direction of ecosystem structure and functioning in the ecosystems examined. Our comparative findings reveal common trends in ecosystem thresholds along pressure gradients and also indicate that thresholds of ecological indicators are useful tools for comparing the impacts of environmental and anthropogenic pressures across multiple ecosystems. These critical points can be used to inform the development of EBM decision criteria.

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Section: Gradient Forest Analysismentioning

confidence: 99%

Section: Model Performancementioning

confidence: 99%

Section: Ecological Indicatorsmentioning

confidence: 99%

Section: Gradient Forest Analysismentioning

confidence: 99%

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Comparing Apples to Oranges: Common Trends and Thresholds in Anthropogenic and Environmental Pressures across Multiple Marine Ecosystems

et al. 2017

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“…To determine the extent to which communities and ecosystems have been altered by fishing, as well as the reversibility of these changes, a range of models (Plagányi, 2007) and ecological indicators (Link, 2005;Rice & Rochet, 2005;Methratta & Link, 2006;Shin et al, 2010) have been applied. Several indicators that focus on different processes, observations or branches of ecology are available, and the approximations based on organism size on the one hand and the organism taxonomy on the other hand, are complementary rather than redundant (Strayer, 1991;Rodríguez & Magnan, 1993).…”

Section: Introductionmentioning

confidence: 99%

Modelling fishery induced impacts on the food web of the continental shelf off central south Chile using a size based network approach

Gómez-Canchong¹,

Quiñones²,

Neira³

et al. 2017

lajar

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Defining ecosystem thresholds for human activities and environmental pressures in the California Current

et al. 2017

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Abstract. The oceans are changing more rapidly than ever before. Unprecedented climatic variability is interacting with unmistakable long-term trends, all against a backdrop of intensifying human activities. What remains unclear, however, is how to evaluate whether conditions have changed sufficiently to provoke major responses of species, habitats, and communities. We developed a framework based on multimodel inference to define ecosystem-based thresholds for human and environmental pressures in the California Current marine ecosystem. To demonstrate how to apply the framework, we explored two decades of data using gradient forest and generalized additive model analyses, screening for nonlinearities and potential threshold responses of ecosystem states (n = 9) across environmental (n = 6) and human (n = 10) pressures. These analyses identified the existence of threshold responses of five ecosystem states to four environmental and two human pressures. Both methods agreed on threshold relationships in two cases: (1) the winter copepod anomaly and habitat modification, and (2) sea lion pup production and the summer mode of the Pacific Decadal Oscillation (PDO). Considered collectively, however, these alternative analytical approaches imply that as many as five of the nine ecosystem states may exhibit threshold changes in response to negative PDO values in the summer (copepods, scavengers, groundfish, and marine mammals). This result is consistent with the idea that the influence of the PDO extends across multiple trophic levels, but extends current knowledge by defining the nonlinear nature of these responses. This research provides a new way to interpret changes in the intensities of human and environmental pressures as they relate to the ecological integrity of the California Current ecosystem. These insights can be used to make more informed assessments of when and under what conditions intervention, preparation, and mitigation may enhance progress toward ecosystem-based management goals.

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Evaluation of quantitative indicators for marine fish communities

Cited by 79 publications

References 42 publications

Comparing Apples to Oranges: Common Trends and Thresholds in Anthropogenic and Environmental Pressures across Multiple Marine Ecosystems

Comparing Apples to Oranges: Common Trends and Thresholds in Anthropogenic and Environmental Pressures across Multiple Marine Ecosystems

Modelling fishery induced impacts on the food web of the continental shelf off central south Chile using a size based network approach

Defining ecosystem thresholds for human activities and environmental pressures in the California Current

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