|Chair(s)/Moderator(s): Valdivia, Abel |
C9.1 11:00 Recruitment variability and the marine protected area effect: Considering multiple life stages in the evaluation of protected areas. Caselle, J.E. *, University of California, Santa Barbara; Grorud-Colvert, K. Oregon State University; White, J.W. University of North Carolina, Wilmington; |
Abstract: Both ecological theory and empirical data demonstrate that recruitment of marine species is highly variable in space and time and this can provide a particular challenge for evaluating the effect of marine protected areas (MPAs) on marine communities. For example, if a particularly strong year class recruits to a protected site and associate reference area, this recruitment effect may in fact swamp any ecological effects of setting aside an area from extractive use. Using a decade-long time series of fish recruitment and adult densities in a network of MPAs in California, our goals were to 1) evaluate the spatial and temporal variability in recruitment of fishes to the MPAs and reference areas, 2) compare these to the observed MPA effect in using species response ratios, and 3) determine the statistical benefit of considering recruitment when evaluating the effect of protection. We found that annual variability in recruitment reflected differences in species settling to MPAs and non-protected areas. However, while an additive MPA effect was detected when evaluating the population responses after ten years of protection, adult response ratios varied annually based on lagged recruitment. Our results indicate that the inclusion of recruitment data in the evaluation of MPAs can contribute significantly to the detection of a true MPA effect. Overall, these data underscore the need for long-term monitoring to ensure that MPAs are meeting their intended goal to preserve populations of marine species across year classes.
C9.2 11:15 Reconstructing coral communities through time to inform effective management strategies for the inshore Great Barrier Reef . Markham, HL *, University of Queensland ; Roff, G University of Queensland ; Zhao, J University of Queensland ; Pandolfi, JM University of Queensland ; |
Abstract: Humans have impacted our marine systems to the extent that even the most remote environments are no longer an effective reference point from which to understand their natural state. For coral reefs, one of the worldâ€™s most vulnerable ecosystems, a key challenge is determining a realistic and site-specific baseline from which to manage them. Historical data provides an ecological reference from which to understand changes and prevents the potential for decision-making to fall against a shifted baseline. Over the past century the water quality within the wet tropics region of the Great Barrier Reef lagoon has notably declined due to high sediment and nutrient-loaded runoff from heavily modified river catchments. This chronic pressure combined with acute disturbance events are reported to have caused a reduction in coral cover and a change of community composition within the inshore systems. Using reef matrix cores to extract fossil coral assemblages from the shallow reef slope, this study looks underneath present-day reef fauna to reconstruct coral assemblages and characterise community shifts over the past 300 years. Within a highly constrained temporal framework (U-series dating) the relative abundance of coral taxa over time allows a baseline prior to human influence to be determined. Results show a clear switch in the coral composition within the last 50 years due to an increased disturbance regime, as assemblages shift from a diverse to an almost mono-generic community.
C9.3 11:30 Assessing ecological correlates of marine bird declines to inform conservation. L. Ignacio Vilchis *, Scripps Institution of Oceanography, University of California San Diego; Joseph K. Gaydos Wildlife Health Center, School of Veterinary Medicine, University of California Davis; Christine K. Johnson Wildlife Health Center, School of Veterinary Medicine, University of California Davis; Scott F. Pearson Wildlife Research Division, Washington Department of Fish and Wildlife; Joseph R. Evenson Wildlife Research Division, Washington Department of Fish and Wildlife; Peter Davidson Bird Studies Canada, Pacific Wildlife Research Centre; Karen L. Barry Bird Studies Canada, Pacific Wildlife Research Centre; Martin G. Raphael , USDA Forest Service, Pacific Northwest Research Station; |
Abstract: Identifying drivers of ecosystem change in large marine ecosystems is central for their effective management and conservation. This is a sizable challenge, particularly in ecosystems transcending international borders, where monitoring and conservation of long-range migratory species and their habitats is logistically and financially problematic. With the goal of elucidating drivers changing ecological communities that could be reflective of wider ecosystem degradation, we synthesized winter surveys from long-term marine bird monitoring programs run by state and provincial wildlife agencies as well as citizen science in the Salish Seaâ€”a transboundary large marine ecosystem in North Americaâ€™s Pacific Northwestâ€”using epidemiological tools. We found that prevalence of species undergoing declines was strongly associated with pursuit divers with specialized diets based on forage fish. Additionally, wide-ranging species without local breeding colonies were more prone to have declines. While a combination of risk factors is most likely driving declines of diving species specializing on forage fish prey, we propose that changes in the availability of low-trophic prey may be forcing wintering range shifts of diving birds in the Salish Sea. Our epidemiological synthesis of long-term trends of a marine predator community provides unique insights into potential drivers of recent ecosystem changeâ€”information that is paramount for species-specific and ecosystem-wide conservation.
C9.4 11:45 An ecosystem-based approach for the Mediterranean Sea in support of the EU Biodiversity Strategy and the Marine Strategy Framework Directive. Piroddi, C *, European Commission, Joint Research Centre; |
Abstract: Marine ecosystems provide an essential contribution to human wellbeing in multiple ways and yet they are pressured by a diversified number of anthropogenic stressors. From a European perspective, a number of policies have been set to reduce and manage the impact of human activities on the marine environment. Among all, the Marine Strategy Framework Directive (MSFD), which is focusing on achieving and maintaining good environmental status (GEnS) of European marine waters by 2020, and the EU Biodiversity Strategy to 2020, which calls for concrete actions to protect marine biodiversity in European waters integrating ecosystem services (ES), as key elements for the conservation approach. Both regulations require the adaption of available indicators to assess marine environmental status and its services. In this study we use an ecosystem based approach, focusing on the Mediterranean Sea, to inform on spatial-temporal indicators outlined in the Marine Strategy Framework Directive (MSFD) and in the marine ecosystem service framework (MES). In particular we focus on mapping selected MES and MSFD indicators resulting from anthropogenic drivers and natural changes using an ecosystem model. The aim is to assess the linkages between those indicators and ecosystem structure and function, and the impact of current and future pressures on the indicators. The overall goal of this mapping and assessment initiative is to support EU policies in maintaining and restoring marine ecosystems and their services in the Mediterranean Sea.
C9.5 12:00 Human impact and natural variability regulate predatory fish biomass in coral reefs. Abel Valdivia *, University of North Carolina at Chapel Hill; Courtney Cox University of North Carolina at Chapel Hill; John Bruno University of North Carolina at Chapel Hill; |
Abstract: The global decline of predators is largely attributed to overexploitation and habitat degradation, yet the environmental factors that naturally control predator abundance remain poorly understood. Restoring predator populations is complicated by the lack of historical baselines and their interplay with environmental variables. Here, we assess the relationship between the biomass of large reef fish predators (sharks, groupers, snappers and jacks) and 18 biotic and abiotic variables at 43 reef sites across a large geographic gradient of human impacts in the Caribbean. We used generalized linear mixed effect models, to (1) attribute regional variability of predators to human impacts and natural environmental factors, and (2) estimate historical baselines of fish predator biomass in the absence of humans. Unsurprisingly, predator biomass was higher in large marine reserves with low poaching and increased as human population substantially decreased. Importantly, over 50% of the variability in predator biomass was also explained by site-level characteristics including prey abundance, habitat complexity, ocean temperature, and primary productivity. Simulated biomass baselines suggest predator declines of 50-90% at some sites. We reveal that bottom-up forces are critical (yet often overlooked) drivers of large predators across gradients of exploitation. We also highlight areas that are natural â€˜hotspotsâ€™ of predator biomass that can be targeted for strategic protection and recovery.
C9.6 12:15 Metapopulation modelling for the management of marine invasions: a case study with Indo-Pacific lionfish (Pterois volitans) on Caribbean coral reefs. Tamburello, N *, Simon Fraser University; CÃ´tÃ©, IM Simon Fraser University; |
Abstract: Metapopulation modelling can pinpoint patches critical for population persistence in fragmented landscapes. While this approach is most frequently used in conservation planning, we argue that it is also well suited to planning invasive species management, particularly in naturally patchy marine habitats. We show how this approach can be used to optimize the distribution of limited management resources among populations of invasive Indo-Pacific lionfish (Pterois volitans) in the Western Atlantic, for which management is currently haphazard. We collected field data on occupancy and movement of lionfish in a network of 34 natural, isolated patch reefs off of Eleuthera, The Bahamas. We use these data in a stochastic patch occupancy model (SPOM) to examine the effects of patch area, connectivity, and proximity to large reefs on the long-term probability of patch occupancy and calculated the relative contribution of each patch to the overall metapopulation capacity. Through simulation, we show that the mean metapopulation size is reduced to a greater extent when prioritizing lionfish removal at patches with the greatest probability of occupancy and largest contribution to metapopulation capacity, but that this effect is diminished by nearby continuous reefs, which provide a strong population rescue effect. By explicitly considering seascape structure when allocating local control efforts, managers can improve the success of marine invasive species management.
C9.7 12:30 Landscape effects in the intertidal around the coastline of Great Britain. Johnson, M.P. *, NUI Galway; Blight, A.J. University of St Andrews; |
Abstract: The landscape-scale structure of habitats can affect the patterns of species richness at smaller scales. Strong patch area effects suggest that habitat loss or creation will impact biodiversity at the scales examined. We examined patch effects along the shoreline of Great Britain to test for patch scale influences on richness in 10 x 10 km hectads. A clustering process identified 3 main groups for intertidal molluscs. The major groupings represent 94% of the 598 hectads with data in the National Biodiversity Network database. The clusters are consistent with a separation of habitat into areas dominated by rocky habitat, soft sediment areas in areas of variable salinity and soft sediment areas on open coasts. Patches were identified as groups of adjoining hectads with the same habitat type. Patch area effects on local (hectad) species richness were weak and only significant for rocky shore habitats. A randomization test suggested that large patches had fewer species than would be expected from a random selection of hectads and that small patches (single hectads) were not depleted in species. The lower total species number than expected in large patches may reflect dispersal limitation across patches or responses to habitat heterogeneity. In conservation terms, the results for smaller habitats imply that small coastal reserves may be adequate for maintaining intertidal molluscan diversity, probably reflecting positive interactions between patches and the surrounding matrix.