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Levin, LA, Dayton PK.  2009.  Ecological theory and continental margins: where shallow meets deep. Trends in Ecology & Evolution. 24:606-617.   10.1016/j.tree.2009.04.012   AbstractWebsite

Continental margins, where land becomes ocean and plunges to the deep sea, provide valuable food and energy resources, and perform essential functions such as carbon burial and nutrient cycling. They exhibit remarkably high species and habitat diversity, but this is threatened by our increasing reliance on the resources that margins provide, and by warming, expanding hypoxia and acidification associated with climate change. Continental margin ecosystems, with environments, constituents and processes that differ from those in shallow water, demand a new focus, in which ecological theory and experimental methods are brought to bear on management and conservation practices. Concepts of disturbance, diversity-function relationships, top-down versus bottom-up control, facilitation and meta-dynamics offer a framework for studying fundamental processes and understanding future change.

Rosenthal, RJ, Clarke WD, Dayton PK.  1974.  Ecology and natural history of a stand of giant kelp, Macrocystis pyrifera, off Del Mar, California. Fishery Bulletin. 72:670-684. AbstractWebsite
Dayton, PK.  1985.  Ecology of kelp communities. Annual Review of Ecology and Systematics. 16:215-245.   10.1146/annurev.ecolsys.16.1.215   AbstractWebsite
Dayton, PK.  1979.  Ecology: a science and a religion. Ecological processes in coastal and marine systems. 10( Livingston RJ, Ed.).:3-18., New York: Plenum Press Abstract
Tegner, MJ, Dayton PK.  1999.  Ecosystem effects of fishing. Trends in Ecology & Evolution. 14:261-262.   10.1016/s0169-5347(99)01650-x   AbstractWebsite

Marine fisheries are in decline worldwide. Increasing problems of bycatch and habitat destruction, and now a growing realization of the role of climate on fished populations, are leading to widespread recognition that the single species approach to fisheries management is not effective. These problems are moving management from its traditional focus on maximizing the yield of individual resources towards broader considerations of direct and indirect impacts of fishing on ecosystems as a whole. Thus, the International Council for the Exploration of the Sea (ICES) and the Scientific Committee for Oceanic Research (SCOR) convened a meeting on the Ecosystem Effects of Fishing this March in Montpellier, France. The objective was to provide a global synthesis of the impacts of fishing on marine ecosystems, to report methods for quantifying ecosystem effects, and to provide a forum for discussion of how objectives relating to the conservation of nature can be integrated into fisheries management. Led by Michael Sinclair (Bedford Institute of Oceanography, Dartmouth, Canada) and Henrik Gislason (University of Copenhagen, Charlottenlund, Denmark), the symposium attracted more than 300 participants from 54 countries*.

Tegner, MJ, Dayton PK.  2000.  Ecosystem effects of fishing in kelp forest communities. ICES Journal of Marine Science. 57:579-589.   10.1006/jmsc.2000.0715   AbstractWebsite

Kelp forests, highly diverse cold water communities organized around the primary productivity and physical structure provided by members of the Laminariales, support a variety of fisheries, and the kelp itself is harvested for alginates. Worldwide, these communities generally share susceptibility to destructive overgrazing by sea urchins. The impact of sea-urchin grazing is governed by the ratio between food availability and grazing pressure, thus factors affecting the abundance of both urchins and kelps are central to ecosystem integrity. Some kelp ecosystems share a second generality, the association of exploitation of various urchin predators with destructive levels of urchin grazing, leading to cascading implications for other species dependent on the productivity and habitat provided by the kelps. Competition between abalones and sea urchins also affects some kelp communities. These ecosystem-structuring processes are complicated by a variety of bottom-up and top-down factors, including variability in ocean climate affecting kelp productivity and recruitment of key species, and echinoid disease, potential ecosystem effects of fisheries for predators, abalones, sea urchins, and kelps are reviewed biogeographically. Given the hundreds to thousands of years that many nearshore marine ecosystems have been exploited, no-take marine reserves may be the only way to determine the true ecosystem effects of fishing. (C) 2000 International Council for the Exploration of the Sea.

Pikitch, EK, Santora C, Babcock EA, Bakun A, Bonfil R, Conover DO, Dayton P, Doukakis P, Fluharty D, Heneman B, Houde ED, Link J, Livingston PA, Mangel M, McAllister MK, Pope J, Sainsbury KJ.  2004.  Ecosystem-based fishery management. Science. 305:346-347.   10.1126/science.1098222   AbstractWebsite
Hewitt, JE, Thrush SF, Dayton PK, Bonsdorff E.  2007.  The effect of spatial and temporal heterogeneity on the design and analysis of empirical studies of scale-dependent systems. American Naturalist. 169:398-408.   10.1086/510925   AbstractWebsite

Processes interacting across scales of space and time influence emergent patterns in ecological systems, but to obtain strong inference and empirical generalities, ecologists need to balance reality with the practicalities of design and analyses. This article discusses heterogeneity, scaling, and design analysis problems and offers potential solutions to improve empirically based research. In particular, we recommend bridging the dichotomy between correlative and manipulative studies by nesting manipulative studies within a correlative framework. We suggest that building on variation, by designing studies to detect variability, rather than fighting it often leads to an increase in generality. We also emphasize the importance of natural history information for determining likely scales of spatial and temporal heterogeneity and the probable occurrence of feedback loops, indirect effects, and interacting processes. Finally, we integrate these concepts and suggest planned iterations between multiscale studies to build up natural history information and test the strength of relationships across space and time. This offers a way forward in terms of heuristically developing models and determining ecological generalities.

Parnell, PE, Lennert-Cody CE, Geelen L, Stanley LD, Dayton PK.  2005.  Effectiveness of a small marine reserve in southern California. Marine Ecology-Progress Series. 296:39-52.   10.3354/meps296039   AbstractWebsite

While relatively small, the San Diego-La Jolla Ecological Reserve is one of the oldest in California, and it contains giant-kelp-forest, boulder-reef, submarine-canyon and sandy-shelf habitats. We evaluated the effectiveness of this 'no-take' marine reserve and gauged its success according to the goals implicit in its design. To overcome the lack of data prior to its establishment, we employed habitat-specific analyses. Our study comprised 4 components: (1) an historical review of its establishment; (2) a survey of conspicuous species in kelp-forest, submarine-canyon, and boulder-reef habitats; (3) comparisons with historical data; (4) a public survey regarding awareness, knowledge, and support of the reserve. Despite 30 yr of protection, only a few sessile or residential species exhibit positive effects of protection, and most fished species have decreased in abundance inside the reserve. However, the reserve protects the largest remaining populations of green abalone Haliotis fulgens and vermillion rockfish Sebastes miniatus in the area, which therefore represent important sources of larvae. Implementation and enforcement of coastal reserves depends on public support, but the results of the public survey indicated a lack of knowledge of the reserve, highlighting the need for improved public education in this respect. The results of the study reflect the limited value of small reserves and document the inadequacy of inside/outside comparisons as tests of reserve effectiveness when baseline and historical data are lacking.

Tegner, MJ, Dayton PK, Edwards PB, Riser KL, Chadwick DB, Dean TA, Deysher L.  1995.  Effects of a large sewage spill on a kelp forest community: catastrophe or disturbance? Marine Environmental Research. 40:181-224.   10.1016/0141-1136(94)00008-d   AbstractWebsite

San Diego's sewage outfall broke during winter 1992, spilling 7.1 x 10(8) litres/d of treated effluent in kelp forest depths for a two month period during an El Nino event. The ecological implications for the Point Loma kelp forest community were studied by comparing long term data with conditions during and after the spill. Surface ammonium concentrations within I km of the break were at potentially toxic levels, and light levels were reduced enough to have inhibited kelp germination and growth. However, because of El Nino conditions, it is unlikely that kelp would have germinated in the absence of a spill. Beyond 1 km, high ammonium concentrations benefitted the nutrient-depleted surface canopy of giant kelp (Macrocystis pyrifera). Measured sedimentation rates were significantly higher near the outfall during the spill and were strongly I elated to wave height; water motion, however, prevented sediment accumulation. Bioassays were conducted on a grid of stations surrounding the outfall. There were significant reductions in the density and growth of microscopic sporophytes of Macrocystis outplanted near the outfall during the spill, but this pattern disappeared in samples collected 11 d after the repair was completed and was not observed again. Sediments collected near the outfall during the spill significantly reduced Macrocystis germ tube elongation; a post repair assay showed no differences with respect to the outfall. No significant effects were observed in outplants of juvenile Macrocystis sporophytes, cup corals, and juvenile abalones. Video transects during the spill and subsequent diving observations provided no evidence of sediment accumulation or negative impacts on established animal populations. Kelp population dynamics at the permanent sites were predictable from existing population structure and El Nino conditions. Damage to kelps, apparently resulting from a combination of low light and nutrient conditions with mechanical damage from storms, construction activity, and barge anchor cables, was observed along the outfall immediately adjacent to the break point. Shortly after the outfall was repaired, ztpwelling improved conditions for kelp germination and growth, and the zone of maximum impact developed into a dense kelp forest. Suspension feeders, detritivores and sea urchins, whose natural history indicates they could have been affected by the spill, showed no unusual population changes. In the context of the continuum of disturbances observed in two decades of population studies at Point Loma, the spill was a modest disturbance similar to the natural vagaries of kelp recruitment. We emphasize that this spill was an intense but not chronic impact during an EI Nino event that also stressed control areas. However, it is representative of massive spills in coastal regions, and the fact that a sewage spill of this magnitude had no lasting effects on a kelp forest community is of general interest.

Tegner, MJ, Dayton PK.  1987.  El Nino effects on southern California kelp forest communities. Advances in Ecological Research. 17:243-279.   10.1016/s0065-2504(08)60247-0   AbstractWebsite

The chapter reviews the effects of the massive oceanic phenomenon on the nearshore kelp communities of the southern California Bight. The effects of this El Niño on intertidal algae in southern California are ambiguous; Gunnill is unable to find a uniform response in seven species of macro-algae. The effects of the 1982-1983 El Niño on California kelp forest communities varied both locally and regionally. The relevance of El Niños to kelp forest community structure must be related to recurrence rates. The effects on kelp community structure will depend on the season of the warm period for example, given the normal summer stress on Macrocystis, warm-water events then are more serious than a similar temperature elevation in winter, and the duration and magnitude of warming. Two major El Niños stand out in recent California history, the events of 1957-1959 and 1982-1984 from the biological perspective, the opposite side of the coin may be even more important to the California Current system. Anti El Niño years, characterized by strong southward transport, low sea level, reduced temperature and salinity, and high zooplankton abundance, are years of high biological productivity.

Dayton, PK, Thrush SF, Agardy MT, Hofman RJ.  1995.  Environmental effects of marine fishing. Aquatic Conservation-Marine and Freshwater Ecosystems. 5:205-232.   10.1002/aqc.3270050305   AbstractWebsite

1. Some effects of fisheries on the associated biological systems are reviewed and management options and their inherent risks are considered. 2. In addition to the effects on target species, other sensitive groups impacted by fishing are considered including marine mammals, turtles, sea birds, elasmobranchs and some invertebrates with low reproductive rates. 3. Other impacts discussed include the destruction of benthic habitat, the provision of unnatural sources of food and the generation of debris. 4. Management options are considered including the designation of marine protected areas, risk aversion, and the burden of proof. 5. A balanced consideration of the risks and consequences of 'Type 1' and 'Type II' errors is advocated.

Kim, S, Hammerstrom K, Dayton P.  2019.  Epifaunal community response to iceberg-mediated environmental change in McMurdo Sound, Antarctica. Marine Ecology Progress Series. 613:1-14.   10.3354/meps12899   AbstractWebsite

High-latitude marine communities are dependent on sea ice patterns. Sea ice cover limits light, and hence primary production and food supply. Plankton, carried by currents from open water to areas under the sea ice, provides a transitory food resource that is spatially and temporally variable. We recorded epifaunal abundances at 17 sites in McMurdo Sound, Antarctica, over 12 yr, and found differences in communities based on location and time. The differences in location support patterns observed in long-term infaunal studies, which are primarily driven by currents, food availability, and larval supply. The temporal differences, highlighting 2004 and 2009 as years of change, match the altered persistence of sea ice in the region, caused by the appearance and disappearance of mega-icebergs. The temporal changes were driven by changes in abundance of species that filter feed on large particulates. The shift in current patterns that occurred due to mega-icebergs decreased the normal food supply in the region. In addition to the decrease in food availability, we suggest that the reduced light resulting from thicker-than-normal sea ice resulted in a shift to smaller phytoplankton. A change in food quality as well as quantity may have influenced the temporal change in epifaunal communities.

Rogers-Bennett, L, Haaker PL, Huff TO, Dayton PK.  2002.  Estimating baseline abundances of abalone in California for restoration. California Cooperative Oceanic Fisheries Investigations Reports. 43:97-111. AbstractWebsite

Abalone populations in California have declined dramatically; however, reliable estimates of baseline abundances are lacking. The lack of sufficient time scales seriously limits the value of most baselines. We use historical data to define baselines for abalone in California and to evaluate current abundances and suggest restoration targets. Using the fishery as a "sampling tool," we estimate that baseline abundances for pink abalone (Haliotis corrugata) were 9.3 million, black abalone were 3.5 million (H. crachcrodii), green abalone (H.fulgens) were 1.5 million, white abalone (H. soreriseni) were 360,000, and threaded abalone (H. kamtschatkana assimilis) were 21,000. All of these species now number less than 1% of their estimated baselines. For species poorly represented in the fishery, we use survey data to estimate that baseline abundances for pinto abalone (H. k. kamtschatkana) were 153,000, and for flat abalone (H. walallensis) were 71,000. Our modern surveys suggest that pinto abalone populations have undergone a ten-fold decline and that flat abalone populations remain similar to their baseline. These baselines underline the dramatic declines in abalone populations and thus define the magnitude of the challenges we face in restoring formerly abundant species. The identification of rare species brings into question the wisdom of fishing species in the absence of baseline information. This approach may serve to help set restoration targets for other depleted species for which we have limited data.

Dayton, PK, Oliver JS.  1980.  An evaluation of experimental analyses of population and community patterns in benthic marine environments. Marine Benthic Dynamics. ( Tenore KR, Coull BC, Eds.).:93-120., Columbia, South Carolina: University of South Carolina Press Abstract