Jenifer E. Dugan

ECOLOGICAL CRITERIA FOR EVALUATING CANDIDATE SITES FOR MARINE RESERVES

Several schemes have been developed to help select the locations of marine reserves. All of them combine social, economic, and biological criteria, and few offer any guidance as to how to prioritize among the criteria identified. This can imply that the relative weights given to different criteria are unimportant. Where two sites are of equal value ecologically; then socioeconomic criteria should dominate the choice of which should be protected. However, in many cases, socioeconomic criteria are given equal or greater weight than ecological considerations in the choice of sites. This can lead to selection of reserves with little biological value that fail to meet many of the desired objectives. To avoid such a possibility, we develop a series of criteria that allow preliminary evaluation of candidate sites according to their relative biological values in advance of the application of socioeconomic criteria. We include criteria that,. while not strictly biological, have a strong influence on the species present or ecological processes. Out scheme enables sites to be assessed according to their biodiversity, the processes which underpin that diversity, and the processes that support fisheries and provide a spectrum of other services important to people. Criteria that capture biodiversity values include biogeographic representation, habitat representation and heterogeneity, and presence of species or populations of special interest (e.g., threatened species). Criteria that capture sustainability of biodiversity and fishery values include the size of reserves necessary to protect viable habitats, presence of exploitable species, vulnerable life stages, connectivity among reserves, links among ecosystems, and provision of ecosystem services to people. Criteria measuring human and natural threats enable candidate sites to be eliminated from consideration if risks are too great, but also help prioritize among sites where threats can be mitigated by protection. While our criteria can be applied to the design of reserve networks, they also enable choice of single reserves to be made in the context of the attributes of existing protected areas. The overall goal of our scheme is to promote the development of reserve networks that will maintain biodiversity and ecosystem functioning at large scales. The values of eco-system goods and services for people ultimately depend on meeting this objective.

The response of macrofauna communities and shorebirds to macrophyte wrack subsidies on exposed sandy beaches of southern California

To investigate the influence of marine macrophyte wrack subsidies on community structure, relationships between community attributes, including species richness, abundance, and biomass of macrofauna and abundance of shorebirds, and a variety of factors, including the standing crop of wrack and beach morphodynamics, were examined on 15 exposed sandy beaches on the southern California coast. The beaches sampled were primarily modally intermediate morphodynamic types, and three were groomed regularly. Species richness, abundance, and biomass of the macrofauna were high compared to values reported for similar beach types in other regions and were not predicted by morphodynamics or other physical factors. Overall species richness and abundance, and the species richness, abundance, and biomass of wrack-associated fauna and selected taxa were significantly correlated with the standing crop of macrophyte wrack. Wrack-associated macrofauna, such as amphipods, isopods, and insects, made up an average of >37% of the species on ungroomed beaches and comprised 25% or more of the total abundance on half of those beaches. The abundance of two shorebird species, plovers that forage using visual cues, was positively correlated with the standing crop of wrack and with the abundance of wrack-associated invertebrates. Significant differences in community structure, including depressed species richness, abundance, and biomass of macrofauna, especially for wrack-associated taxa, were associated with beach grooming and provided strong evidence for the bottom-up effects of wrack subsidies. Grooming also reduced the prey available to vertebrate predators, such as shorebirds. Substantial ecological effects of the large-scale disturbance and removal of organic material, food resources, and habitat are associated with beach grooming. These results suggest that macrophyte wrack subsidies strongly influence macrofaunal community structure, higher trophic levels, and ecological processes on exposed sandy beaches. The supply of macrophyte wrack should be considered as a factor in ecological studies of exposed sandy beaches, particularly where macrophyte production is high.

APPLYING ECOLOGICAL CRITERIA TO MARINE RESERVE DESIGN: A CASE STUDY FROM THE CALIFORNIA CHANNEL ISLANDS

Using ecological criteria as a theoretical framework, we describe the steps involved in designing a network of marine reserves for conservation and fisheries man- agement. Although we describe the case study of the Channel Islands, the approach to marine reserve design may be effective in other regions where traditional management alone does not sustain marine resources. A group of agencies, organizations, and individuals established clear goals for marine reserves in the Channel Islands, including conservation of ecosystem biodiversity, sustainable fisheries, economic viability, natural and cultural heritage, and education. Given the constraints of risk management, experimental design, monitoring, and enforcement, scientists recommended at least one, but no more than four, reserves in each biogeographic region. In general, the percentage of an area to be included in a reserve network depends on the goals. In the Channel Islands, after consideration of both conservation goals and the risk from human threats and natural catastrophes, scientists recommended reserving an area of 30-50% of all representative habitats in each biogeo- graphic region. For most species of concern, except pinnipeds and seabirds, information about distributions, dispersal, and population growth was limited. As an alternative to species distribution information, suitable habitats for species of concern were used to locate potential reserve sites. We used a simulated annealing algorithm to identify potential reserve network scenarios that would represent all habitats within the smallest area possible. The analysis produced an array of potential reserve network scenarios that all met the established

Application of ecological criteria in selecting marine reserves and developing reserve networks

Marine reserves are being established worldwide in response to a growing recognition of the conservation crisis that is building in the oceans. However, designation of reserves has been largely opportunistic, or protective measures have been implemented (often overlapping and sometimes in conflict) by different entities seeking to achieve dif- ferent ends. This has created confusion among both users and enforcers, and the proliferation of different measures provides a false sense of protection where little is offered. This paper sets out a procedure grounded in current understanding of ecological processes, that allows the evaluation and selection of reserve sites in order to develop functional, interconnected networks of fully protected reserves that will fulfill multiple objectives. By fully protected we mean permanently closed to fishing and other resource extraction. We provide a frame- work that unifies the central aims of conservation and fishery management, while also meeting other human needs such as the provision of ecosystem services (e.g., maintenance of coastal water quality, shoreline protection, and recreational opportunities). In our scheme, candidate sites for reserves are evaluated against 12 criteria focused toward sustaining the biological integrity and productivity of marine systems at both local and regional scales. While a limited number of sites will be indispensable in a network, many will be of similar value as reserves, allowing the design of numerous alternative, biologically adequate net- works. Devising multiple network designs will help ensure that ecological functionality is preserved throughout the socioeconomic evaluation process. Too often, socioeconomic cri- teria have dominated the process of reserve selection, potentially undermining their efficacy. We argue that application of biological criteria must precede and inform socioeconomic evaluation, since maintenance of ecosystem functioning is essential for meeting all of the goals for reserves. It is critical that stakeholders are fully involved throughout this process. Application of the proposed criteria will lead to networks whose multifunctionality will help unite the objectives of different management entities, so accelerating progress toward improved stewardship of the oceans.

Adaptations of bivalves to different beach types

Burrowing ability, shape and density of 12 bivalve species from a wide range of beach types were compared as part of a general investigation of the adaptations of bivalves to the swash climates experienced on exposed sandy beaches. The genera used were Donax, Mesodesma, Tivela, Siliqua, Atactodea, Paphies and Donacilla. Burrowing rates varied widely and burrowing ability showed no relation to beach type along the reflective/dissipative beach gradient, i.e. from beaches with low wave energy and coarse sand to beaches with high wave energy and fine sand. Burrowing rate indices (BRIs) ranged from 2 to 17 (rapid to very rapid) and tended to be higher for juveniles of most species. Bivalve species from dissipative beaches varied in shape from almost blade-shaped to almost spherical, whereas those from reflective beaches were more uniform generally wedge-shaped. Species with the most flattened shapes and (greatest height/width ratios) tended to burrow fastest. Striking interspecific differences were found in densities of whole intact bivalves, these ranging from 1.04 g · cm−3 to 2.10 g · cm−3. The highest densities were recorded in bivalves from reflective beaches and the lowest in bivalves from dissipative beaches. Bivalve species typical of intermediate and reflective beaches were successfully separated from those typical of dissipative beaches on the basis of their density, morphology and BRI, particularly their size and density, using discriminant analysis. It is concluded that small species with high density and streamlined shape are best adapted to the dynamic swash conditions that characterise reflective beaches.

Estuarine and Coastal Structures: Environmental Effects, A Focus on Shore and Nearshore Structures

Rapidly growing populations and expanding development are intensifying pressures on coastal ecosystems. Sea-level rise and other predicted effects of climate change are expected to exert even greater pressures on coastal ecosystems, exacerbating erosion, degrading habitat, and accelerating shoreline retreat. Historically, society’s responses to threats from erosion and shoreline retreat have relied on armoring and other engineered coastal defenses. Despite widespread use on all types of shorelines, information about the ecological impacts of shoreline armoring is quite limited. Here we summarize existing knowledge on the effects of armoring structures on the biodiversity, productivity, structure, and function of coastal ecoystems.

Ecological Implications of Extreme Events: Footprints of the 2010 Earthquake along the Chilean Coast

Deciphering ecological effects of major catastrophic events such as earthquakes, tsunamis, volcanic eruptions, storms and fires, requires rapid interdisciplinary efforts often hampered by a lack of pre-event data. Using results of intertidal surveys conducted shortly before and immediately after Chiles 2010 M w 8.8 earthquake along the entire rupture zone (ca. 34–38°S), we provide the first quantification of earthquake and tsunami effects on sandy beach ecosystems. Our study incorporated anthropogenic coastal development as a key design factor. Ecological responses of beach ecosystems were strongly affected by the magnitude of land-level change. Subsidence along the northern rupture segment combined with tsunami-associated disturbance and drowned beaches. In contrast, along the co-seismically uplifted southern rupture, beaches widened and flattened increasing habitat availability. Post-event changes in abundance and distribution of mobile intertidal invertebrates were not uniform, varying with land-level change, tsunami height and coastal development. On beaches where subsidence occurred, intertidal zones and their associated species disappeared. On some beaches, uplift of rocky sub-tidal substrate eliminated low intertidal sand beach habitat for ecologically important species. On others, unexpected interactions of uplift with man-made coastal armouring included restoration of upper and mid-intertidal habitat seaward of armouring followed by rapid colonization of mobile crustaceans typical of these zones formerly excluded by constraints imposed by the armouring structures. Responses of coastal ecosystems to major earthquakes appear to vary strongly with land-level change, the mobility of the biota and shore type. Our results show that interactions of extreme events with human-altered shorelines can produce surprising ecological outcomes, and suggest these complex responses to landscape alteration can leave lasting footprints in coastal ecosystems.

Give Beach Ecosystems Their Day in the Sun

The Intergovernmental Panel on Climate Change Fourth Assessment Report ([ 1 ][1]) largely overlooked the impacts of climate change on marine ecosystems ([ 2 ][2]). In their Review (“The impact of climate change on the worlds marine ecosystems,” 18 June, p. [1523][3]), O. Hoegh-Guldberg and J. F

Burrowing abilities and swash behavior of three crabs, Emerita analoga Stimpson, Blepharipoda occidentalis Randall, and Lepidopa californica Efford (Anomura, Hippoidea), of exposed sandy beaches

To investigate factors related to the distribution of intertidal species, and specific predictions of the swash exclusion hypothesis for exposed sandy beaches, we compared the burrowing abilities and swash behavior of three species of anomuran crabs in the superfamily Hippoidea (Emerita analoga, Blepharipoda occidentalis and Lepidopa californica) which commonly inhabit the intertidal and shallow subtidal zones of beaches along the California coast. Burrowing times in the laboratory increased significantly with crab size for all species in five sediment grain sizes ranging from fine sand to gravel (0.15 to 3.24 mm). For each species, burrowing times differed significantly among sand grain sizes, ranging from 0.3 to 21.5 s. Burrowing times for the hippid crab, E. analoga, were relatively constant across sediment types, while those of the albuneid crabs, B. occidentalis and L. californica, were rapid in fine to medium sands, and much slower in coarser sediments. Our results indicate that E. analoga is a substrate generalist while L. californica and B. occidentalis are substrate sensitive. Pre-burrowing times and behavior, distance moved, and burrowing times differed among the species in the swash zone. Combined times of preburrowing and burrowing were shorter than the swash period (6 s) for most E. analoga individuals. Fifty percent of the individuals of L. californica reached the substrate and burrowed in the swash period, while no individuals of B. occidentalis burrowed in that time. Pre-burrowing behavior and time may be valuable in explaining spatial and temporal patterns in the distribution of hippoid crabs on California beaches. Our results support predictions of the swash exclusion hypothesis concerning the burrowing and locomotory abilities of sandy beach macrofauna. The substrate generalist characteristics, and unique orientation and swimming abilities of the hippid crab, E. analoga, in intertidal swash may help explain the success of this species and its congeners, and have important implications for understanding patterns of macrofauna community structure on exposed sandy beaches in California and other regions.

Geographic variation in the reproductive biology of the sand crab Emerita analoga (Stimpson) on the California coast

Reproductive characteristics were measured in 23 populations of the sand crab Emerita analoga Stimpson in midsummer over ≈ 1000 km of the California coast. Significant geographic patterns were found in the female size at maturity, the size and age distribution of ovigerous crabs, and an estimate of population fecundity. No geographic patterns were found in egg size and size-specific fecundity. Crabs from southern sites reproduced at smaller sizes and younger ages and attained smaller maximum sizes than crabs from northern sites. Young of the year crabs at northern sites matured at larger sizes, reproduced in smaller proportions, and produced larger initial clutches than southern crabs. Size at maturity and the size distribution of ovigerous crabs were inversely correlated with water temperature. Fecundity was significantly correlated with crab carapace length in all populations but no geographic trend was found in size-specific fecundity. The lack of overlap in the size ranges of ovigerous crabs did not allow direct comparisons of fecundity-size regressions between northern and southern populations. The relationships of fecundity and crab size varied significantly among populations in both the northern and the southern groups. Estimates of population fecundity decreased significantly from north to south. That trend was related to geographic patterns in the size and age distribution of ovigerous crabs.