MSC - Marine Stewardship Council. Purpose

Transcription

1 MSC - Marine Stewardship Council Consultation Document Benthic Impacts- Background Paper 1: Defining Habitat, Habitat Structure, and Consultation Dates: 20 th July-31 st August, 2012 MSC Contact: Jodi Bostrom <jodi.bostrom@msc.org> Purpose The purpose of this paper is to recommend changes to the MSC Certification Requirements (CR) and Guidance to the CR (GCR) for comment during stakeholder consultation. Introduction The MSC asked a team of consultants to prepare a report on the global best practices for managing, measuring, and mitigating the impacts of fishing on benthic habitats (Grieve et al., 2011). One of the findings from this report is that the MSC does not clearly define the terms habitat, habitat structure, and habitat role, despite the use of these terms in the Habitats Performance Indicators (PIs) language. This, therefore, could be an issue when trying to ensure consistent and robust assessments. Following the Grieve et al. (2011) finding, the MSC drafted definitions for those three terms and provided them for feedback at the March stakeholder workshop and the March to April public consultation. Key Points from Grieve et al. (2011) For its Risk-Based Framework (RBF) in the GCR, the MSC uses the Substratum, Geomorphology, and Fauna (SGF) method to identify the benthic habitat units being assessed. Substratum refers to sediment type, geomorphology to the seafloor topography, and fauna to the dominant faunal group. The SGF implies that the habitat includes the organisms living therein. However, while habitat refers to an area inhabited by a particular organism, a biotope refers to both the habitat and its associated species (Costello, 2009). Often a species and a habitat are indistinguishable (e.g., coral reefs and other biogenic structures) and are at the very least dependent (Grieve et al., 2011). Grieve et al. (2011) proposed the following definition for habitat : the chemical and bio-physical environment where an organism resides. The basic units are pelagic habitats (the water column) or benthic habitats (the seafloor structure including attached flora and invertebrate fauna). In relation to benthic habitat particularly, the consultants pointed out that attached flora (and fauna) can have important habitat-forming or functional properties that may be impacted significantly by fishing. The consultants suggested that the above proposed definition offered a practical definition of habitats that is consistent with that which appears in the RBF sections of the CR and GCR (Grieve et al., 2011). Grieve et al. (2011) suggested that habitat structure is the amount, composition, and threedimensional arrangement of biological and physical matter in an area, providing refuge and surface area for food production within a marine ecosystem (after Warfe and Barmuta, 2004). In simpler terms, habitat structure is the physical arrangement of matter that supports plant and animal life (ibid). Based on Warfe and Barmuta (2004), an applicable definition for habitat role might be the range of services provided to an organism or ecosystem, including, but not limited to,

2 mediating trophic interactions between predator and prey and between predators, providing refugia, and influencing behaviour of organisms (Grieve et al., 2011). For example, seagrasses or mangroves may provide predator refuge, whilst adjacent soft-bottom environments may provide foraging opportunities. It is important to note that these services may be life-stage and size dependent and can change according to the density of biotic and abiotic physical matter within the habitat structure itself (Grieve et al., 2011). Original Proposed Definitions The following definitions were proposed for discussion at the March workshop and for consideration during the subsequent consultation period: Habitat is the chemical and bio-physical area where an organism lives, which may include attached flora or fauna such as (but not limited to) corals or seagrasses and other attached non-target species. Habitat structure is the arrangement of physical structures that support plant and animal communities. Habitat role is the range of services provided to an organism, including, but not limited to, mediating trophic interactions between predators and predators and prey, providing refuge, and influencing the behaviour of organisms. Comments from First Stakeholder Workshop and Public Consultation Habitat The workshop attendees generally felt that the proposed definition for habitat was good, but some felt that oceanographic dynamics should be recognised and included, as well as habitat-forming flora, redrafting to something like: The chemical, bio-physical, oceanographic conditions including associated habitat-forming flora and fauna where target organism exists. Others felt that the proposed habitat definition was organism-centric and scale dependent and contrasts with the SGF approach used in the RBF. They suggested that the definition s starting point should be the SGF approach, but include flora, given the MSC s potential implementation of a default RBF-like process. These sentiments were echoed in a comment received during public consultation. It was also noted that it would be helpful if the definition clarified whether or not fauna is in reference to sessile habitat forming species only. However, expressing concern that revised definitions could add unnecessary complexity, another public consultation comment suggested the following definition: Habitat is an area with similar chemical and bio-physical characteristics. Habitat Structure and Habitat Function Some workshop attendees stated that the proposed definition for habitat structure was acceptable but wondered if defining habitat role was necessary. A public consultation comment voiced the opinion that habitat structure is the more important term. Workshop attendees and public consultation comments also noted that there are inconsistencies between the use of function and role within the PI language that need to be addressed. Technical Advisory Board Working Group Discussion

3 During the May Technical Advisory Board (TAB) working group meeting, the group discussed the outcomes and comments from the stakeholder workshop and public consultation in some detail. The TAB proposed some wording changes to the definitions in preparation for the second public consultation. Recommendations New Proposed Definitions and CR and GCR Changes Based on the above information, the MSC is recommending the definitions and changes to the CR and GCR as outlined below in Appendix 1. In short, the MSC is recommending a definition for habitat that attempts to incorporate as many of the stakeholder views as possible while reducing complexity and is recommending definitions for habitat structure and habitat function since both of these terms appear in the PI language. Additionally, it is recommended that all instances of habitat role be changed to habitat function (in line with the terminology of the PI language) to decrease confusion and increase consistency. References Costello, M.J Distinguishing marine habitat classification concepts for ecological data management. Marine Ecology Progress Series 397: Grieve, C., D.C. Brady, and H. Polet Best Practices for Managing, Measuring, and Mitigating the Benthic Impacts of Fishing: Final Report to the Marine Stewardship Council. Unpublished work. Warfe, D.M. and L.A. Barmuta Habitat structural complexity mediates the foraging success of multiple predator species. Oecologia 141:

4 Certification Requirements Appendix 1 CB3.14 Habitats Outcome PI (PI 2.4.1) Table CB17: PI2.4.1 Habitats outcome PISGs Component PI Scoring issues SG60 SG80 SG100 Habitats Outcome Status The fishery does not cause serious or harm to habitat structure, considered on a regional or bioregional basis, and function. a. Habitat status The fishery is unlikely to reduce habitat structure and function to a point where The fishery is highly unlikely to reduce habitat structure and function to a point where There is evidence that the fishery is highly unlikely to reduce habitat structure and function to a point where CB CB The team shall assess the habitats component in relation to the effects of the fishery on the structure and rolefunction of the habitats impacted by the fishery. The team shall use these interpretations: CB Serious harm means gross change in habitat types or abundances, and disruption of the functionrole of the habitats. CB Irreversibility means changes that are expected to take much longer to recover than the dynamics in un-fished situations would imply, some sort of regime change is implied from which recovery may not automatically occur. CB CB CB The team shall consider the full extent of the habitats when assessing the status of habitats and the impacts of fishing, and not just the part of the habitats that overlap with the fishery. The team should score the fishery at SG100 if evidence shows that the fishery has no impact on habitats. The team shall interpret the terms unlikely, highly unlikely and evidence for in SG60, SG80 and SG100 as in Table CB18. Guidance to the Certification Requirements GCB3.14 Habitats Outcome PI (PI 2.4.1) GCB Guidance to Annex CB clause CB Usually habitats impacted by the fishery are bottom habitats rather than pelagic habitats, but impacts on the biotic aspects of pelagic habitats could be considered. If a benthic habitat is being assessed, the team may consider the following points:

5 a. Substratum sediment type (e.g., hard substrate) b. Geomorphology seafloor topography (e.g., flat rocky terrace) a.c. Biota dominant floral and/or faunal group(s) (e.g., kelp forest and mixed epifauna, respectively) While the productivity and regenerative ability of biogenic habitats would affect their resilience under fishing, and may be useful surrogates for consideration of status and reversibility, it is the ecological rolefunction of the habitat and the ecosystem services that it provides that is the intent of assessment. a. For example particular habitats may determine the carrying capacity of target, bycatch or ETP species, and a mosaic of habitats may be necessary for some species to complete their life cycle or determine the overall composition of the ecological community. GCB Guidance to Annex CB clause CB Examples of harm include the loss (extinction) of habitat types, depletion of key habitat forming species or associated species to the extent that they meet criteria for high risk of extinction, and significant alteration of habitat cover/mosaic that causes major change in the structure or diversity of the associated species assemblages. GCB Guidance to Annex CB clause CB For example if a habitat extends beyond the area fished then the full range of the habitat should be considered when evaluating the effects of the fishery. The full range of a habitat shall include areas that may be spatially disconnected from the area affected by the fishery and may include both pristine areas and areas affected by other fisheries. GCB Knowledge of the structure and rolefunction of habitats is often limited, and there is not general or widespread agreement on the equivalence of targets and limits for fishery impacts. Annex AA AA3 Vocabulary Term Habitat Habitat Structure Habitat Function Definition The chemical, bio-physical environment including biogenic structures where fishing takes place. The arrangement of physical, biogenic formations that support plant and animal communities. The range of services provided to an organism, including, but not limited to, mediating trophic interactions, reproduction, shelter, and feeding, and influencing the behaviour of organisms.