final-temperate-marine-protected-areas-report-for-parks-can

The Role of Marine Protected Areas in Temperate Marine Ecosystems; an Analysis of Empirical Evidence, Site Selection Methodology and Design Principles by Anne K Salomon B.Sc (Hons.) Queen’s University, Kingston 1996 M.Sc Candidate University of British Columbia, Vancouver 2000 for Tomas Tomascik Cliff Robinson Canadian Heritage Parks Canada Western Canada Service Center February 15th 2000  Anne K Salomon Table of Contents Introduction Report Objectives Literature Review An Introduction to Marine Protected Areas .4 Marine Protected Area Goals; Biodiversity Conservation and Fisheries Management Proposed Ecological Values and Benefits Ecological Limitations and Conflicts Empirical Evidence Demonstrating the Ecological Impact of MPAs Abalone on BC’s West Coast Lingcod in the Strait of Georgia Lingcod and Rockfish in Puget Sound .11 Marine Reserves in New Zealand 12 Chilean Rocky intertidal 14 Benthic community structure in Southern California 15 Estuarine No-Take Sanctuary in Florida 16 Future Requirements 17 Marine Protected Area Design and Site Selection Theory 18 Comparison of Marine and Terrestrial Reserve Design and Site Selection Theory 18 Reserve Site Selection Criteria 18 Terrestrial Site Selection Methods 19 Factors Governing Marine Protected Area Design and Site Selection 20 Larval Dispersal and Open Populations 20 Source / Sink Dynamics 20 Identifying “Sources” and “Sinks” 21 The Allee Effect 21 Modelling Marine Protected Area Design 22 Conclusion; An Issue of Urgency .23 Quantitative Data Comparing Temperate MPAs and Adjacent Waters 24 Internet Information Relevant to MPA Science and Research 34 World Wide Web Addresses .34 List Services .35 MPA Researchers 35 Literature Cited 37 Introduction The exploitation of living marine resources is considered to be the single greatest threat to marine biodiversity (National Research Council 1995) The spatial restriction of human activities in the marine environment in the form of marine protected areas (MPAs) is becoming recognized worldwide as a tool to control this threat The use of MPAs in BC and Canada as a method for conserving marine biodiversity and enhancing fishery yields is slowly gaining credibility among scientists, fisheries managers, fishers and the general public Although acceptance is increasing, uncertainty and opposition exists in part due to the lack of empirical evidence demonstrating the function of marine reserves in temperate regions Though legal, political and social factors also present major obstacles to MPA establishment, this report will focus on the current scientific constraints through the analysis of both theoretical and empirical MPA related research Report Objectives The specific objective of this report is to analyze and synthesize relevant scientific information regarding the primary roles, site selection criteria, and design principles of MPAs in temperate marine ecosystems This includes a critique of current empirical evidence demonstrating the ecological impacts of MPAs located in temperate and subtropical zones plus the creation of a database that contains the data discussed A compilation of Internet websites, list services and scientific contacts pertinent to MPA science is also provided Marine protected areas have become a strongly advocated approach to marine conservation strategies, however, to date, there has been little theoretical basis or scientific justification for their design or location To assure the effectiveness of MPAs, marine conservation theory needs to be expanded (Allison et al 1998) However, though scientific knowledge about marine and coastal ecosystems if far from complete, this lack of information should not halt conservation efforts The intent of this report is not to point out the paucity of “scientific proof” for MPAs in temperate zones and the need for more research before MPAs are implemented Rather, it was written to demonstrate the urgent need to establish replicate temperate marine reserves in order to undertake reliable comparative studies to assess the ecological impacts of reserves Available information exists to start experimenting and establishing MPAs An adaptive management approach to MPA design will allow for change as we gain insight into marine systems and the best methods to conserve them Hopefully, this report will promote active discussion on the theoretical underpinnings that should form the basis for MPA design, evaluation, and site selection, and prompt management agencies to take action based on our current knowledge Literature Review AN INTRODUCTION TO MARINE PROTECTED AREAS Humans are currently imposing unprecedented pressure on marine systems worldwide (Norse 1993, Lubchenco et al 1995, West 1997) As a result, the oceans are exhibiting evidence of this stress including mass mortalities of marine species, an increase in harmful algal blooms, population declines, shellfish bed closures, and the collapse of fisheries such as Atlantic Canada’s cod This has prompted marine conservation efforts to identify both proximate and ultimate causes and develop solutions Marine protected areas (MPAs) are increasingly being recognised as an effective management tool for conserving marine resources and the ecosystems in which they are embedded (Upton 1992, Roberts 1997, Roberts 1998) MPAs, otherwise known as fishing refugia, marine reserves or marine sanctuaries, are spatially explicit areas where the exploitation of marine resources is restricted (Agardy 1997) Though the concept of spatial restriction as a management tool is not new (Beverton and Holt 1957), the implementation of MPAs is relatively recent and the theoretical and empirical framework for their design is in its infancy (Allison et al 1998) MPAs have become increasingly advocated by fisheries managers because spatial restriction confers protection not offered by other management approaches such as the protection of critical areas like feeding and rearing grounds (Norse 1993), and the intrinsic prevention of recruitment overfishing (Dugan and Davis 1993) Furthermore, they allow use to hedge our bets against the scientific uncertainty that plagues fisheries science MPAs are also gaining credibility as an effective tactic for conserving marine biodiversity To date, MPAs have been designated in a wide variety of habitats, with a number of conservation goals Marine Protected Area Goals; Biodiversity Conservation and Fisheries Management Marine Protected Areas may be established to meet a variety of conservation objectives that can be divided into two distinct categories; the conservation of biodiversity (biodiversity reserves) and the enhancement of fisheries yields (fishing refugia) (Allison et al 1998) Ultimately, fishing refugia are created to increase the biomass or population size of a commercially important target species through the emigration of adults and juveniles from the refuge and/or the export of larvae to surrounding exploited areas (Allison et al 1998) They are also created to provide undisturbed habitat for an intensively fished species (Dugan and Davis 1993) and to provide “insurance” against potential fisheries management mistakes Biodiversity reserves may be established to protect areas of high biodiversity, critical areas, a vulnerable species or population, or a sensitive habitat They may also be created to conserve ecological processes and trophic structure while establishing baseline research areas (Norse 1993) All of these goals are important, however, the extent to which they are compatible remains unclear For instance, protecting a species with high per capita interaction strength may help protect community structure and cause a local increase in biodiversity (Castilla and Duran 1985) Conversely, when large predator species begin accumulating in a reserve, certain prey species may become extirpated from the area resulting in a local decrease in biodiversity (Salomon et al 1999) Nonetheless, the ecological rationale is equivalent for both types of reserves Both harvest refugia and marine reserves are established to decrease the chances of organisms interfacing with anthropogenic threats (Wallace 1999a) However, methods for evaluating the biological effectiveness of a reserve will undoubtedly depend on the reserve’s goal Proposed Ecological Values and Benefits An extensive range of potential benefits has been proposed for MPAs Perhaps the most important biological role of a MPA is its function as a refuge from exploitation Once released from fishing or collecting pressure, a population within a protected area is structured by natural mortality rather than fishing mortality (i.e fishers tend to exploit larger size-class individuals) Therefore, the density and average size of individuals within a reserve should increase (Polunin and Roberts 1993) Because older, larger individuals are typically more fecund than younger, smaller individuals, the reproductive output of a protected population would theoretically be larger than that of an exploited population Although difficult to demonstrate, MPAs have been proposed to supply adults and juveniles to adjacent exploited areas (Alcala and Russ 1990, Attwood and Bennett 1994) and act as centers for larval dispersal Reserves could therefore lead to an enhancement of harvestable stocks Fishing impacts an ecosystem in various ways Target species populations are reduced, as are nontarget species through by-catch Furthermore, by removing functionally important species such as top predators, fishing can often dramatically change community structure A MPA designed to protect a specific species will, by default, protect nontarget species and the entire ecosystem within the marine reserve Moreover, In the process of some fishing practices such as trawling, habitat is often destroyed MPAs will preclude fishing gear impacts on benthic communities (Sobel 1996) MPAs can also serve as an insurance policy by acting as a buffer against recruitment failure and unanticipated yet potentially disastrous fisheries management mistakes (Allison et al 1998, Walters 1998) Because catch limits are based on predictions of highly variable environmental parameters and inaccurate stock assessments, uncertainty is prevalent and the probability of error in fisheries management is high A protected population could act as a recovery population if that population was self-replenishing (Carr and Reed 1993) and could provide baseline information on nonexploited populations Finally, MPAs can serve as ecological benchmarks against which future change could be judged Summary of the Proposed Benefits of Marine Protected Areas -modified from Sobel (1996) Conservation of Biodiversity Improvement of Fishery yields             Protect ecosystem structure and function Protect food webs and ecological processes Maintain trophic structure Retain keystone species Prevent loss of vulnerable/threatened species Preserve “natural” community composition Maintain physical structure of habitat Maintain high quality feeding and rearing grounds Preclude fishing gear impacts Retain “natural” trophic interactions Provide long-term monitoring /controlled areas for assessing anthropogenic impacts           Protect spawning stock & increase spawning stock biomass Enhance reproductive capacity i.e.: boost egg and larvae production Export larvae to adjacent waters Supply spill-over of adults and juveniles Improve spawning sites by minimizing disturbance Reduce chances of recruitment overfishing Prevent over-fishing of vulnerable species Mitigate adverse genetic impacts of fishing Reduce bycatch mortality Provide insurance against stock collapse Provide information on unfished population necessary for proper management of exploited stocks Ecological Limitations and Conflicts MPAs have several limitations and therefore must be coupled with conservation efforts outside their boundaries Firstly, because MPAs effectively reduce the total area available to be fished, without an overall reduction in fishing effort, even well designed and sited MPAs will only serve to displace fishing effort and concentrate it elsewhere (Fogarty 1999) Therefore, MPAs must be coupled with harvest restrictions outside the reserve It is important to note that even protected populations are subject to variable recruitment and may experience intricate dynamics due to complex interactions among species within a reserve For example, a build up of predator biomass within a reserve may result in a depression of prey within the reserve boundaries (Polunin and Roberts 1993, Walters et al 1998, Walters 1998) Furthermore, MPAs will most likely confer very little protection to widely dispersing and migrating species such as salmon and whales (Walters et al 1998, Walters 1998) Even for species with limited dispersal, reserve effectiveness will be highly dependent on patterns of population replenishment (Allison et al 1998) If optimal reserve design and location for a species is dependent upon dispersal distance (Quinn et al 1993) then a MPA designed for a target species may in fact confer inadequate protection for another species Finally, marine reserves offer no protection from threats originating from outside the protected area such as oil spills and contamination by other chemicals Furthermore, episodic climatic events such as el Nino-Southern Oscillations (ENSOs) can span thousands of kilometers and can have a dramatic impact on both protected and nonprotected populations EMPIRICAL EVIDENCE DEMONSTRATING THE ECOLOGICAL IMPACT OF MPAS The ecological impacts of marine reserves in tropical ecosystems have been studied extensively (Alcala 1988, Alcala and Russ 1990, Bennett and Attwood 1991, Polunin and Roberts 1993, Attwood and Bennett 1994), however, until recently, very few empirical studies in temperate marine ecosystems have been conducted (Palsson and Pacunski 1995, Estes and Carr 1999, Babcock 1999) Although current mathematical and ecosystem-based models of temperate marine systems (Guenette and Pitcher 1999, Salomon et al 1999) indicate that spatial protection from exploitation should serve as an effective fisheries management tool in temperate marine ecosystems, little empirical evidence exists This paucity of research is in part due to the fact that there are few marine reserves located in temperate waters in which to test their ecological impact This section reviews the research that has been conducted in temperate systems, most of which demonstrate or suggest reserve effects, including increased density and size of exploited species and several which report indirect ecosystem effects Abalone on BC’s West Coast In a study comparing forms of marine reserves on British Columbia’s West Coast, Wallace (1999b) found that of the sites subject to a coast-wide abalone closure since 1990 had insufficient abalone to provide the necessary sample size for statistical comparisons presumably due to poaching Abalone sizes differed significantly among the enforced reserve areas surveyed (an ecological reserve, a military site and a prison reserve) and were significantly largest at the de facto prison reserve which had, by default, provided 39 years of protection from exploitation (Wallace 1999b) When relative abundance was accounted for, the military site had the highest potential reproductive output Assuming adequate enforcement, these results provide strong evidence supporting the role of reserves in re-establishing populations of marine species with a low dispersing adult stage However, it is difficult to determine if these results can be attributed causally to the enforced marine reserves primarily because patterns of abalone recruitment are influenced by a number of factors such as regional hydrodynamics, benthic topography and composition, as well as settlement and survival rates The conclusion that reserves are more productive than exploited areas is weakened by the lack of replicate reserves of similar habitat This works does however provide an explicit example of the importance of considering population viability when it comes to selecting the location of a “no-take” reserve within MPA network If a MPA is to be self-replenishing and export larvae (Roberts 1997), marine reserves must incorporate a viable population of the target species Abalone are broadcast aggregate spawners that require high densities to ensure fertilization Therefore, biogeographic representation of the species is obviously insufficient criteria on which to select reserve location Furthermore, providing evidence for the ecological effectiveness of MPAs on species-by species basis may justify marine reserves whose goal is to protect a single species from overexploitation However, ecosystem impacts, such as the change in biomass of other trophic levels, should not be neglected in the evaluation process Cumulative spatial effects, such as the ability of MPAs at providing seed sources for surrounding areas, should be taken into account in assessments of ecological effectiveness Palsson and Pacunski 1995 Table 1: Density of Copper Rockfish (note: all num bers below are estim ated off graphs from original publication, including confidence intervals) Mean Densities of Copper Rockfish / transect 95% CI Mean Densities of Copper Rockf ish >40 cm / transect 95% CI Mean Copper Rockfish Biomass(kg) / Transect PB 95% CI 4 3 BC 5 BI OR 2.5 *EUP 32 24 47.7 TI 6.3 1.3 3.7 1.5 *SC 11.9 1.9 5.8 1.5 Location Table 2: Density of Quillback Rockfish (note: all num bers below are estim ated off graphs from original publication, including confidence intervals) Mean Densities of Location Quillback Rockfish 95% Mean Densities of Quillback Rockfish >40 cm 95% CI Mean Quillback Rockf ish Biomass(kg) / Transect BC 46.5 7.5 BI 7.5 OR 0 *EUP 22 95% CI PB 7.5 9.5 2.5 2.5 15.7 Table 3: Density of Lingcod (note: all num be rs below are e stim ated off graphs from original publication, including confidence intervals) Mean Densities of Location Lingcod / transect 95% CI Mean Densities of Lingcod >70 cm / transect 95% CI Mean Lingcod Biomass (kg) / Transect 95%CI 0.5 5 5 PB 0.5 0.4 BC 1.5 BI 0.5 0.25 OR 0.5 *EUP 3.3 3.3 0.5 38.2 TI 1.2 0.25 0.04 0.2 1.6 *SC 1.5 0.25 0.5 0.2 3.6 0.5 * = Marine reserve 28 Palsson and Pacunski 1995 Table 4: Size freque ncy dis tribution of target s pecie s in e xploited and protected areas Copper Frequency (%) Quillback Frequency (%) Lingcod Frequency (%) Size Exploited Area MPA Exploited Area MPA Exploited Area MPA 10 26 18 0 20 31 17 65 17 0 30 46 20 20 40 19 18 37 19 50 36 23 60 0 41 70 0 0 12 80 0 0 20 90 0 0 100 0 0 21 110 0 0 120 0 0 12 130 0 0 n=364 n=763 n=294 n=127 n=77 n=95 Table 5: Reproductive output of Copper Rockfish and Lingcod Mean copper rockfish eggs (X 10E6) / transect 95% CI Mean lingcod eggs (X10E5) / transect 95% CI PB 0.2 1.25 0.2 0.625 BC 0.1 1.25 0.35 0.625 BI 0.2 0.625 OR 0.1 0.625 Location *EUP 7.6 1.25 4.7 0.625 TI 0.35 0.4 0.15 0.25 *SC 0.65 0.4 0.4 0.25 29 Cole et al 1990 Table 1: Mean dens ities of Se a Urchins at s ites inside and outside the Leigh Marine Reserve (data estim ated off graph in paper) Density (m2) SE (+/-) Reserve Site Reserve Site 5.4 Reserve Site 6.5 Reserve Site 4.8 Reserve Site 6.2 Nonreserve Site 5.3 Nonreserve Site 4.4 Nonreserve Site 1.3 Babcock et al 1999 Table 1: Habitat Change at Leigh 1978 to 1996 (data estim ated from graph in paper) Year Mean Density Urchin grazed rockflats (m2) 95% CI Kelp Mean Density Urchin grazed rock-flats (m2) 95% CI Sea urchin Mean Density Kelp forests (m2) Mean Density Kelp forests 95% CI (m2) Kelp 95% CI Sea urchin 1978 0.8 1.1 4.9 2.7 19.6 3.9 0.38 0.13 1996 9.4 5.9 1.4 1.3 10.8 1.4 0 Table 2: Eeffects of no-tak e rese rves on predator abundance (data estim ated from graph in paper) Location Max # of Snapper 95% CI Spiny Lobster Density (ha-1) 95% CI Rockf lats Frequency (%) 95% CI reserve (Leigh) 4.8 1.5 590 230 11 reserve (Taw ) 1.7 0.9 300 150 18 nonreserve (Leigh) 0.2 0.1 120 100 50 10 nonreserve (Tw a.) 0.1 0.1 220 100 32 Leigh Marine Reserve Taw haranui Marine Park 30 More no et al 1986 Table 1: Estim ated densities of C conchelepas in reserve and harvested areas Year Localities Reserve N Exploited N 19 (+/- 32.7) 24 15.8 (+/- 20) 18 1981 22.4 (+/- 32) 28 (+/- 17.4) 18 1982 12.4 (+/- 19.4) 18 14 (+/- 18.2) 18 1983 15 (+/- 22.6) 24 (+/- 14.8) 18 1984 15.2 (+/- 25.6) 48 1.6 (+/-4) 48 1980 Enge l & Kvite k 1998 Table 1: Me an dens ity of e pifaunal invertebrates (>5cm ) per 500 m in lightly traw le d and heavily traw led areas (data estim ated off graph) Location * Ptilosarcus sp *Mediaster sp *Urticina sp * Pleurobranchae (sea pens) (sea stars) (sea anemones) californica (sea (#/500m2) (#/500m2) (#/500m2) slug) (#/500m2) Rathbunaster sp (#/500m2) Stylatula sp (#/500m2) Metridium sp (#/500m2) Lightly Traw led 38 23 15 12 41 23 Heavily Traw led 3 22 *=significant diff erence betw een lightly traw led and heavily traw led sites Table 2: Mean density of polychaetes, oligochaetes , crustaceans and ophiuroids in lightly traw led and he avily traw led are as (data estim ated off graph) Location Polychaetes oligochaete s crustacean Oct Dec Dec Sep Dec (#/.1m2 Dec Sep *Oct (#/.1m2 Sep Oct (#/.1m2 (#/.1m2 Oct (#/.1m2 Sep ) (#/.1m2) (#/.1m2) (#/.1m2) ) (#/.1m2) (#/.1m2) ) ) (#/.1m2) ) (#/.1m2) Lightly Traw led 195 90 140 85 10 10 180 60 110 16 30 36 Heavily Traw led 182 89 72 255 40 60 240 40 40 50 42 61 *=signif icant dif ference betw een lightly traw led and heavily traw led sites 31 Jons on et al 1999 Table 1: Standardized m ean catch rates for fished and unfished s ites Gamefish (fish/set) Spotted Seatrout (fish/set) Red Drum (fish/set) Black Drum (f ish/set) Common Snook (fish/set) Stripped Mullet (fish/set) 6.4 1.4 1.2 0.77 0.37 13.3 4.5 12.3 0.84 3.68 0.81 1.24 0.13 0.93 0.26 0.8 13 20.4 mean standardized CPUE fished sites 2.4 0.58 0.19 0.06 0.07 5.1 minimum 1.5 0.36 0.11 not given 4.2 maximum 2.5 0.66 0.3 not given 0.04 7.5 Location mean standardized CPUE unf ished sites minimum maximum Table 2: Specie s com position of tram m el net catches in fis hed and unfishe d sites Location Spot (%) Pinfish (%) Red Drum Black Drum Snook FBR Menhaden (%) Seatrout (%) 26 19 21 19 0 FIR 2 16 24 45 0 FML 41 10 13 20 0 UEBC 10 37 37 UBR 15 26 35 10 3 18 53 UWBC F= Fished Catf ish (%) Mullet (%) U= Unfished Table 3: Num ber of specie s found in fished and unfished areas Location # of species FBR 21 FIR 27 FML 29 UEBC 21 UBR 28 UWBC 29 Jonson e t al 1999 32 Table 4: Differe nces in m edian length betw een fished and unfished sites Fished Areas Median Lengh N (mm) Species Unf ished Areas Median N length (mm) T-stat P Spotted seatrout 162 358 511 387 41140