Cadre décisionnel pour la translocation aux fins de la conservation de poissons et de moules d'eau douce inscrits sur la liste de la LEP

Abstract

Conservation translocations are identified in many management plans and recovery strategies as potential tools for improving the survival or recovery of freshwater fish and mussel species listed under the Species at Risk Act (SARA). This document provides a general science-based decision support framework to help inform the potential use of conservation translocations in recovery planning. Conservation translocations include supplementation, reintroduction, mitigation translocation, and assisted colonization. They have been defined here as the act of intentionally moving individuals of a species with the aim of improving survival or recovery of a focal species. Increasing population recruitment, establishing a population, or rescuing a population from immediate extirpation are the three primary mechanisms by which conservation translocations may achieve improved survival or recovery of SARA-listed species. The decision support framework considers the potential ecological benefits to the focal species and the ability to achieve those benefits, relative to the ecological risks to the source and recipient populations of the focal species, as well as broader ecosystem components and processes. The five step decision support framework consists of: Identification of objectives; Assessing the probability of achieving the means and fundamental objectives; Assessing the ecological risks; Compiling and weighing scientific evidence to inform the decision; and, Implementing and monitoring the effects. Conservation translocations can pose ecological risks to the focal species and broader ecosystem components in both the source and recipient habitats that include: The loss of population persistence; Loss or alteration of genetic variation; Changes in community and ecosystem dynamics; and, The potential for transmitting disease. Increased knowledge of population characteristics, species ecology, species habitat requirements and availability, community composition, and potential threats in, or to, the source and recipient locations reduces uncertainty and risk about the outcomes of conservation translocation. The science-based rationale for initiating conservation translocations should be informed by the potential ecological benefits and risks to SARA-listed freshwater fishes and mussels, relative to the risks to other ecosystem components. Given the uncertainties and limited implementation in Canada, when conservation translocations are pursued they should be considered in a long-term experimental context and will require adaptability in implementation and robust monitoring to detect both intended and unintended outcomes, and modify or discontinue the translocation program, if needed. Context-specific protocols that consider the focal species and ecosystems under consideration must be established prior to implementing and monitoring conservation translocations, and remain flexible and adaptable both within the short-term and long-term for the duration of the program. This advice focuses on the ecological considerations for conservation translocations; given the experimental nature of these projects, a socio-economic analysis would also be required before implementation.