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Effects of Sea Otters on Rocky Shore Food Webs, Biodiversity and Ecosystem Services

copyright Russell Markel

PI’s and Collaborators: Kai Chan (IRES, UBC), Chris Harley (Zoology, UBC), Evgeny Pakhomov (EOS, UBC), Jon Shurin (UC San Diego), Terre Satterfield (IRES, UBC), Villy Christensen (Fisheries Centre, UBC), Rashid Sumaila (Fisheries Centre, UBC), Anne Salomon (SFU), West Coast Aquatic, Parks Canada, Fisheries and Oceans, Canada.
Postdoctoral Associates: Rebecca Martone, Russell Markel, Jessica Clasen
Graduate students: Ed Gregr, Gerald Singh, Brock Ramshaw, Jordan Tam, Jordan Levine, Maria Espinosa Romero

Widespread ecosystem change caused by human activities, such as over-exploitation of resources or the loss of top predators, leading to economic depression and cultural loss, are dilemmas faced by human-communities worldwide. In response, management agencies strive to integrate information on ecosystem structure and productivity and human perceptions and values into models of resource management. Following extirpation of sea otters from the BC coast during the Maritime Fur Trade (~1778-1911), populations of some nearshore benthic invertebrates, including sea urchins, abalone, and geoduck, became “hyper-abundant”. Although coastal First Nations have harvested these and other invertebrates for thousands of years, reliance upon these resources increased in the absence of sea otters. Furthermore, beginning in the early 1970’s, burgeoning commercial fisheries targeting these same species became highly lucrative. Thus, re-introduction of sea otters to the west coast of Vancouver Island, also in the early 1970’s, set the stage for conflict between this native keystone predator and coastal communities, economies and cultures dependent upon shellfish resources.

In order to inform how human-communities are affected by and can adapt to ecosystem changes along the west coast of Vancouver Island, we formed a consortium of researchers at UBC to investigate the ecological and social effects of sea otter re-introduction. The objectives of this inter-disciplinary research project are framed in the context of “ecosystem services”, broadly defined as the benefits to humans provided by ecosystems. We ask what are the consequences of trophic cascades for nearshore ecosystems and the benefits they provide for people?

Specifically:
• How will ecosystems be affected across the seascape?
• What are the consequences for nearshore diversity and productivity?
• How do changes in ecosystem states and functions link to ecosystem-service provisioning?
• What are the consequences for and responses of human communities?

Cumulative Impacts to Coastal and Marine Ecosystems and Ecosystem Services

Collaborators: Dr. Kai Chan, Dr. Megan Mach, Gerald Singh, Erin Crockett, Allison Thompson, Ed Gregr, Laura Dee, Joey Bernhardt, Cathryn Clarke-Murray, Caitlin Millar  (Institute for Resources, Environment and Sustainability, University of British Columbia); Dr. Miriam O, Hilary Ibey, Kate Ladell, Dr. Jim Boutillier (Fisheries and Oceans, Canada)

Despite the importance and irreplaceability of coastal ecosystems and the services they provide (i.e., the production of benefits to people by ecosystems), degradation and loss of coastal ecosystems over the past two to three decades is intense and increasing worldwide. This degradation is in large part because, even with longstanding mandates for coordinated management, coastal systems are still managed piecemeal, one species, sector, or issue at a time. Even where decision-making institutions have committed to integrated management across systems and sectors, they lack an understanding of how multiple human drivers of ecological change interact in ecosystems. To provide for the well-being of coastal communities, resource management must content with cumulative human impacts and their affects on ecosystem-service provisioning.

There is little information available on the impacts of multiple human activities on ecosystem service provisioning.  Initiatives to map or catalogue ecosystem services bring attention to the need for integrated management approaches, but do not give managers the detailed understanding that is necessary in order to assess trade-offs and make informed decisions.  In parallel, global and regional initiatives have developed approaches to identify, rank and map the cumulative impacts of human activities to coastal and marine habitats, but ignore the links to ecosystem services.  What is missing is a transparent, transferable method to determine the cumulative impacts of human activities from land, freshwater and marine systems and how they influence the production of ecosystem services.

We are building on the concept of evaluating cumulative human impacts to ecosystems, and extending this to the cumulative impacts of human activities on the ecosystem services themselves.  An evaluation of the impacts of human activities on a variety of ecosystem services will allow for effective management based on the ability to spatially prioritize conservation initiatives, and successfully assess the trade-offs of various human activities. Working with the Department of Fisheries and Oceans, Canada, we are integrating ecosystem services concept into an ecosystem risk assessment framework and examining the relative risk to ecosystem services within the Pacific North Coast Integrated Management Area (PNCIMA). Working in concert with DFO scientists and planners, we hope to help set priorities and strategies for this large ocean management area in British Columbia.

Ecosystem-based fisheries management and certification: extending certification principles and assessment

Collaborators: Dr. Fiorenza Micheli (Stanford University), Dr. Antonio Bodini (University of Parma, Italy), Dr. Salvador Lluch-Cota (CIBNOR, Mexico), Dr. Geoff Shester (Oceana), Dr. Giulio DeLeo (Stanford University)

Novel approaches for promoting sustainable food from the oceans and vibrant coastal communities offer an important glimmer of hope amidst ongoing degradation of marine ecosystems and the irreplaceable benefits provided by these systems. Emerging research indicates that sustainable seafood provided by fisheries and aquaculture can be enhanced through the creation of innovative agreements and incentives.  Current approaches to managing fisheries and aquaculture fall short in part because they (a) do not account for multiple users across the seascape; (b) do not encompass ecological, social, and economic components of sustainability; and (c) set the bar impossibly high for many communities and fisheries. Overcoming these obstacles requires initiatives that address components of resilient social-ecological systems, system-wide assessment rather than a subset of activities, continual improvement rather than a static bar of sustainability, equitable benefit sharing, and formalized mechanisms for compensating direct investment in ecosystem conservation.

We are developing and evaluating a novel approach to fisheries certification applied to cover all fishing activities within a geographic area (e.g. Vizcaino peninsula) by a common set of resource harvesters (e.g. fishing cooperatives). The project includes the development of tools and indicators for evaluating the ecosystem impacts of multiple fisheries occurring in the same ecosystem. The benefits of understanding cumulative impacts from many activities occurring in an ecosystem will include new stewardship incentives and mechanisms, and tools and perspectives for implementing ecosystem-based fisheries management in multi-species fisheries.

Small-Scale Fisheries: Linking Biophysical and Socio-Economic Processes

Collaborators: Dr. Fiorenza Micheli, Dr. Salvador Lluch-Cota, Dr. Bonnie McCay, Dr. Chris Costello, Dr. Jim Wilson, Dr. Laura Gonzalez, Dr. Tim Keitt, Dr. Sergio Guzman-del-Proo, Dr. Elisa Serviere, Dr. German Ponce-Diaz, Dr. Alison Haupt, Dr. Geoff Shester, Dr. Wendy Weisman

Despite the overwhelming social and economic importance of small-scale fisheries, and the widespread degradation of the associated marine resources and ecosystems, these systems are poorly understood. Community-based management, co-management, and market incentives can all foster long-term stewardship and ecosystem protection, but their applicability and success to date has varied. Beginning in the 1930’s, the nearshore fisheries of Baja California were organized into local cooperatives, which were granted exclusive fishing rights on local stocks, including abalone, lobsters, oysters, clams, and shrimp. Cooperatives throughout the coast operate under different permits that give them greater or lesser degrees of control over their local resources, and vary broadly in their ecological setting and in the success and sustainability of their main fisheries (primarily for lobster and abalone). Our objective is to develop an integrated framework for addressing environmental and socioeconomic processes underlying the varying success of the small-scale fisheries of Baja California. Through my involvement in these multi-disciplinary research program studying the complex biophysical and socioeconomic feedbacks within management and conservation, I hope to be able to make significant contributions to better integrating ecological understanding into conservation of marine seascapes and associated assemblages.

Geographic variation in demography of a temperate-reef snail: importance of multiple life-history traits

Collaborators: Dr. Fiorenza Micheli

Individual- and population-level performance may reflect trade-offs between energy allocation to different key demographic processes, such as growth and reproduction, which can, in turn, be influenced by local biotic and abiotic conditions. We explored geographic variation in demographic rates of an exploited benthic species, the wavy-turban snail Megastraea undosa, along the Pacific coast of Baja California, Mexico.

We compared key life-history traits (i.e. fecundity, size at maturity, growth, and survivorship) of populations existing between 20 and 170 km apart under different conditions of ocean temperature and food availability. Trade-offs between growth and reproduction were evident across this environmental gradient, with higher growth rates in warmer locations leading to lower size-specific investment in gonad production. Because later onset of reproduction in populations from warmer areas was compensated by greater fecundity at larger sizes, geographic variation in life-history strategies resulted in similar age-specific reproductive output among different populations. However, we observed that, while there is substantial variation in demographic rates of the study species, harvest management is applied uniformly, and this results in southern populations achieving lower reproductive output before they reach a legally harvestable size. Our results highlight the importance of considering geographic variation in multiple life-history traits when managing across a mosaic of land- and seascapes characterized by varying environmental conditions.

 

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