Research Document - 2007/060

Species at Risk: Habitat Quantification Literature Review

By McCarthy, J.H.

Abstract

As the jurisdiction responsible for aquatic species, provisions of the Species at Risk Act (SARA) require that the Department of Fisheries and Oceans (DFO) must identify critical habitat for threatened and endangered aquatic species and protect such habitat from destruction. Workshops and projects over the last five years have provided the scientific foundations for identifying critical habitat for species at risk, and guidelines are likely to be developed in 2007/08.

This project conducted a review of the scientific literature on methods for the quantification of the amount of critical habitat available to populations of animals, with a focus on aquatic species, particularly fish (marine and freshwater) and marine mammals. In total, four approaches were identified that have been used to identify critical habitat; each with its own set of possible models, assumptions and limitations. The approaches have been described as Optimal Reserve Size, Area per Individual, Meta-analysis and Matrix Models.

Most of the papers that describe the approaches suggest that the lack of data for a particular species should not be a deterrent to starting the assessments described. In fact, the lack of data and the need for a framework that incorporates the uncertainties associated with many population parameters appears to be the impetus for most approaches. Many advocate using data from similar species or species that have similar life histories. Many see the assessment process, whatever the process, as an initial step in structuring the available data and a means to identify the gaps and focus research.

Many of the methods described are based on species population vitals such as fecundity, survival and recruitment and habitat quantity and/or quality. It has been noted that while habitat quantity may limit a population by acting on a single life-cycle stage, habitat quality may act on several life-cycle stages and hence improvements in habitat quality may benefit populations on numerous levels without the identification of the actual population limiting factor. This may be important in Species-at-Risk as identified habitat quality issues could be addressed without, or prior to, the determination of critical habitat.

Complete document (PDF, 171 KB)

Accessibility Notice

This document is available in PDF format. If the document is not accessible to you, please contact the Secretariat to obtain another appropriate format, such as regular print, large print, Braille or audio version.