K dominance curves

AWAITING REVIEW

Indicator summary

 Summary of indicator structure and function

Definition and/or background

The following is from Fulton et al 2004a -

The K-dominance curve is a powerful tool for measuring abundance trends in communities over time. K-dominance curves are the cumulative ranked abundance against a log species rank (ICES 2001A, Jennings et al. 2001). The logic behind the use of these curves as indicators is that only the subset of species that can tolerate perturbation will thrive and the rest will decline or disappear. Thus, the steepest and most elevated curve shows the lowest diversity and the most perturbed system state (Rice 2000). This metric has wide application for measuring changes in relationships over time or comparing fished and unfished areas and could potentially be applied to track species assemblages that have been identified as diagnostic of habitat types. ... The potential drawbacks of this method are that changes can be difficult to ascribe to fishing (so reference areas would helpful) and the effects of fishing may not be clear if small species are targeted (as in some pelagic fisheries) before large-bodied top predators (Rochet and Trenkel 2003). Further research into the utility of k-dominance curves across a range of fisheries and ecosystems could clarify these effects of targeting.

Partial dominance curve

In cases where a single abundant species dominates the system to the point it overwhelms the shape of the k-dominance curve, the partial dominance curve will be more useful (Trenkel and Rochet 2003). The partial dominance curve uses relative abundance estimates calculated with respect to only those species with a lower rank (Clarke 1990). Thus it is not overwhelmed by the single most abundant species and allows for consideration of several of the most abundant species.

Attribute

Community structure

Purpose

Fisheries

Data required

The following is from Fulton et al 2004a -

• Numbers of each species
• Biomass

Ecosystem applicability

The following is from Fulton et al 2004a -

Should be applicable to all ecosystem types.

Robustness

The following is from Fulton et al 2004a -

Potentially high: the curves do indicate changes in community diversity, but applying them may be hampered by the requirement of collecting data of comparable thoroughness for all sites or times. In addition, reference areas and knowledge of the size of targeted species may be required to aid in the identification of effects due to fisheries rather than other factors. Despite this, it has been found that K-dominance curves (along with partial dominance and ABC curves, see below) contain more information on changes in assemblages than univariate measures and are as easily contrasted and interpreted (Rice 2000).

Current status and trends

The following is from Fulton et al 2004a -

In a study of the North Sea, it was found that K-dominance curves more accurately pinpointed fishing effects, by identifying decreases in abundance of indicator species (e.g. k-selected species vulnerable to exploitation), than diversity indices for the community, which changed very little (Jennings et al. 2001).

References

Fulton, E.A., Smith, A.D.M., Webb, H., and Slater, J. (2004a) Ecological indicators for the impacts of fishing on non-target species, communities and ecosystems: Review of potential indicators. AFMA Final Research Report, report Number R99/1546.

References that Fulton et al uses for this indicator:

Clarke, K. R. 1990. Comparisons of dominance curves. Journal of Experimental Marine Biology and Ecology 138: pp 143-57.

ICES. 2001a. Report of the Working Group on Ecosystem Effects of Fishing Activities. International Council for the Exploration of the Seas, CM 2001/ACME: 09, 102pp.

Jennings, S., M.J. Kaiser, and J.D. Reynolds. 2001.  Marine fisheries ecology.,. 417 p . London: Blackwell Science.

Rice, J.C. 2000. Evaluating fishery impacts using metrics of community structure. ICES Journal of Marine Science 57: pp 682-88.

Rochet, M.-J., and V. M. Trenkel. 2003. Which community indicators can measure the impact of fishing? a review and proposals. Canadian Journal of Fisheries and Aquatic Science 60: pp 86-99.

Trenkel, V.M., and M.-J. Rochet. 2003. Performance of indicators derived from abundance estimates for detecting the impact of fishing on a fish community. Canadian Journal of Fisheries and Aquatic Sciences 60: pp 67-85.

Background reading

Fulton, E.A., Fuller,M., Smith, A.D.M., and Punt, A. (2004) Ecological indicators of the ecosystem effects of fishing: Final report. AFMA Final Research Report, report Number R99/1546.

Citation

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Last modified on: Apr 11, 2014 15:20

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