109 research outputs found
Neighborhood benthic configuration reveals hidden social diversity: classified benthic data
No full text<p>Ecological interactions among benthic communities are crucial for shaping marine ecosystems. Understanding these interactions is essential for predicting how ecosystems will respond to environmental changes, invasive species, and conservation management. However, determining the prevalence of species interactions at the community scale is challenging. To overcome this challenge, we employ tools from social network analysis, specifically exponential random graph modeling (ERGM). Our approach explores the relationships among animal and plant organisms within their neighborhoods. Inspired by companion planting in agriculture, we use spatiotemporal co-occurrence as a measure of mixed species interaction. In other words, the variety of community interactions based on co-occurrence defines what we call "co-occurrence social diversity." Our objective is to use ERGM to quantify the proportion of interactions at both the simple paired level and the more complex triangle level, enabling us to measure and compare co-occurrence social diversity. Applying our approach to the Spanish coastal zone across 8 sites, 5 depths, and sunlit/shaded aspects, we discover that 80% of sessile communities, consisting of over a hundred species, exhibit co-occurrence social diversity, with 5% of species consistently forming associations with other species. These organism-level interactions likely have a significant impact on the overall character of the site.</p><p>Funding provided by: Spanish Ministry of Science and Education*<br>Crossref Funder Registry ID: <br>Award Number: </p><p>a) Study Sites</p>
<p>The field data selection coincided with a program to quantify changes in the sessile community along a depth gradient in multiple locations of two distant geographic areas. The Spanish islands of Illes Medes and L'illa de Benidorm are located in the Mediterranean Sea and are nature reserves. L'illa de Benidorm is located about 3.5km from the coast, near Benidorm, and has been part of the Sierra Helada Natural Park since 2005. Illes Medes is an archipelago of seven islands about 0.85 km from L'Estartit. It has been protected since 1983 and became a National Protected Natural Park in 2010. These two locations were selected due to their proximity to the coast, ease of sampling, rocky bottoms, and because they are island enclaves close to the coast.</p>
<p>b) Sampling design</p>
<p>During May and June 2010, 6 dive sites in Illes Medes and 2 dive sites in L'illa de Benidorm were selected. For each site, except Garbí and Gros due to a lack of suitable substrate, a photophilous aspect was paired with a sciaphilous aspect. To capture the impact of depth on the community assemblages, each site was surveyed at different depths along the rocky reef wall at 2, 4, 7, 14, and 23 m deep. The sciaphilous aspects could not be located for the 2 sites in L'illa de Benidorm and only one set of transects at various depth profiles were photographed. Based on the continuous line transect method, photo quadrats using a camera (Sony Cyber-shot Vario-Tessar 10.1 Mpx with a constant 45cm distance measurement frame) covered a 5m long transect for each depth profile. Approximately 25 overlapping images were captured per transect. Later back in the laboratory, we identified every species (where possible) directly next to the photographed transect tape for each centimeter division so that 500 data points were recorded per transect. The final dataset contains 17 sites with five depth transects, resulting in 85 sets of benthic data.</p>
Supplementary Figures and Tables from Neighborhood benthic configuration reveals hidden social diversity
No full textFigures for the paper V4.docxPeer reviewe
Neighbourhood benthic configuration reveals hidden co-occurrence social diversity
No full textEcological interactions among benthic communities are crucial for shaping marine ecosystems. Understanding these interactions is essential for predicting how ecosystems will respond to environmental changes, invasive species, and conservation management. However, determining the prevalence of species interactions at the community scale is challenging. To overcome this challenge, we employ tools from social network analysis, specifically exponential random graph modelling (ERGM). Our approach explores the relationships among animal and plant organisms within their neighbourhoods. Inspired by companion planting in agriculture, we use spatiotemporal co-occurrence as a measure of mixed species interaction. In other words, the variety of community interactions based on co-occurrence defines what we call 'co-occurrence social diversity'. Our objective is to use ERGM to quantify the proportion of interactions at both the simple paired level and the more complex triangle level, enabling us to measure and compare co-occurrence social diversity. Applying our approach to the Spanish coastal zone across eight sites, five depths, and sunlit/shaded aspects, we discover that 80% of sessile communities, consisting of over a hundred species, exhibit co-occurrence social diversity, with 5% of species consistently forming associations with other species. These organism-level interactions probably have a significant impact on the overall character of the site. This article is part of the theme issue 'Connected interactions: enriching food web research by spatial and social interactions'.The present study was funded by the Spanish Ministry of Science and Education (MPA-STAR, grant 200730I005 and MARMOL, CMT2007-66635.Peer reviewe
The effects of a stressed inshore urban reef on coral recruitment in Suva harbour, Fiji -Data
No full textA relic inshore reef ecosystem adjacent to the Fijian capital of Suva and another remote inshore reef were monitored monthly from July 2014 to July 2015 for coral recruitment, sedimentation rates, coral cover, temperature and light intensity. Despite a major sewage spill in Suva Harbour in December 2014, the municipal inshore site, exposed to constant anthropogenic activity, recorded no significant differences in coral spat abundance (except for the family Poritidae) on artificial substrata compared to the remote inshore site. Total yearly spat abundance was 106 on municipal reef and 132 on remote reef, while average daily sediment trap collection rates (g.cm2.day-1) were significantly higher in the municipal site for the entire duration of monitoring. Total annual Particulate Organic Matter content in sediment was also significantly higher in the municipal site (107.51 g.cm ), compared to the remote site (43.37 g.cm ). Mean light intensity was significantly lower for the municipal site (69.81 lum/ft ) compared to the remote site (239.26 lum/ft ), with Photosynthetically Active Radiation also lower for the former (800-1066.66 µmol m s ) compared to the latter (3266.66-3600 µmol m s ). The lack of significant differences in coral spat recruitment rates suggests that settling larvae may be unable to distinguish between sub-optimal and optimal sites probably as a consequence of interference with coral settlement cues arising from anthropogenic development
Thermal biases and vulnerability to warming in the world’s marine fauna
No full textA critical assumption underlying projections of biodiversity change associated with global warming is that ecological communities comprise balanced mixes of warm-affinity and cool-affinity species which, on average, approximate local environmental temperatures. Nevertheless, here we find that most shallow water marine species occupy broad thermal distributions that are aggregated in either temperate or tropical realms. These distributional trends result in ocean-scale spatial thermal biases, where communities are dominated by species with warmer or cooler affinity than local environmental temperatures. We use community-level thermal deviations from local temperatures as a form of sensitivity to warming, and combine these with projected ocean warming data to predict warming-related loss of species from present-day communities over the next century. Large changes in local species composition appear likely, and proximity to thermal limits, as inferred from present-day species’ distributional ranges, outweighs spatial variation in warming rates in contributing to predicted rates of local species loss
New approaches to marine conservation through scaling up of ecological data
No full textIn an era of rapid global change, conservation managers urgently need improved tools to track and counter declining ecosystem conditions. This need is particularly acute in the marine realm, where threats are out of sight, inadequately mapped, cumulative, and often poorly understood, thereby generating impacts that are inefficiently managed. Recent advances in macroecology, statistical analysis, and the compilation of global data will play a central role in improving conservation outcomes, provided that global, regional, and local data streams can be integrated to produce locally relevant and interpretable outputs. Progress will be assisted by (a) expanded rollout of systematic surveys that quantify species patterns, including some carried out with help from citizen scientists; (b) coordinated experimental research networks that utilize large-scale manipulations to identify mechanisms underlying these patterns; (c) improved understanding of consequences of threats through the application of recently developed statistical techniques to analyze global species’ distributional data and associated environmental and socioeconomic factors; (d) development of reliable ecological indicators for accurate and comprehensible tracking of threats; and (e) improved data-handling and communication tools.<br/
Global conservation outcomes depend on marine protected areas with five key features
No full textIn line with global targets agreed under the Convention on Biological Diversity, the number of marine protected areas (MPAs) is increasing rapidly, yet socio-economic benefits generated by MPAs remain difficult to predict and under debate. MPAs often fail to reach their full potential as a consequence of factors such as illegal harvesting, regulations that legally allow detrimental harvesting, or emigration of animals outside boundaries because of continuous habitat or inadequate size of reserve. Here we show that the conservation benefits of 87 MPAs investigated worldwide increase exponentially with the accumulation of five key features: no take, well enforced, old (>10 years), large (>100km2), and isolated by deep water or sand. Using effective MPAs with four or five key features as an unfished standard, comparisons of underwater survey data from effective MPAs with predictions based on survey data from fished coasts indicate that total fish biomass has declined about two-thirds from historical baselines as a result of fishing. Effective MPAs also had twice as many large (>250mm total length) fish species per transect, five timesmore large fish biomass, and fourteen times more shark biomass than fished areas. Most (59%) of the MPAs studied had only one or two key features and were not ecologically distinguishable from fished sites. Our results show that global conservation targets based on area alone will not optimize protection of marine biodiversity. More emphasis is needed on better MPA design, durable management and compliance to ensure that MPAs achieve their desired conservation value.Fil: Graham, J. Edgar. University of Tasmania; AustraliaFil: Stuart Smith, Rick D.. University of Tasmania; AustraliaFil: Willis, Trevor J.. University of Portsmouth; Reino UnidoFil: Kininmonth, Stuart. University of Tasmania; Australia. Stockholms Universitet; SueciaFil: Baker, Susan C.. University of Tasmania; AustraliaFil: Banks, Stuart. Charles Darwin Foundation; EcuadorFil: Barrett, Neville S.. University of Tasmania; AustraliaFil: Becerro, Mikel A.. Natural Products and Agrobiology Institute; EspañaFil: Bernard, Anthony T. F.. South African Environmental Observation network; SudáfricaFil: Berkhout, Just. University of Tasmania; AustraliaFil: Buxton, Colin D.. University of Tasmania; AustraliaFil: Campbell, Stuart J.. Wildlife Conservation Society; Estados UnidosFil: Cooper, Antonia T.. University of Tasmania; AustraliaFil: Davey, Marlene. University of Tasmania; AustraliaFil: Edgar, Sophie C.. Department of Water; AustraliaFil: Försterra, Günter. Pontificia Universidad Católica de Valparaíso; ChileFil: Galvan, David Edgardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; ArgentinaFil: Irigoyen, Alejo Joaquin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; ArgentinaFil: Kushner, David J.. United States National Park Service; Estados UnidosFil: Moura, Rodrigo. Universidade Federal do Rio de Janeiro; BrasilFil: Parnell, P. Ed. University of California at San Diego. Scripps Institution of Oceanography; Estados UnidosFil: Shears, Nick T.. The University Of Auckland; Nueva ZelandaFil: Soler, German. University of Tasmania; AustraliaFil: Strain, Elisabeth M. A.. Universidad de Bologna; ItaliaFil: Thomson, Russell J.. University of Tasmania; Australi
Abundance and local-scale processes contribute to multi-phyla gradients in global marine diversity
No full textAmong the most enduring ecological challenges is an integrated theory explaining the latitudinal biodiversity gradient, including discrepancies observed at different spatial scales. Analysis of Reef Life Survey data for 4127 marine species at 2406 coral and rocky sites worldwide confirms that the total ecoregion richness peaks in low latitudes, near +15°N and −15°S. However, although richness at survey sites is maximal near the equator for vertebrates, it peaks at high latitudes for large mobile invertebrates. Site richness for different groups is dependent on abundance, which is in turn correlated with temperature for fishes and nutrients for macroinvertebrates. We suggest that temperature-mediated fish predation and herbivory have constrained mobile macroinvertebrate diversity at the site scale across the tropics. Conversely, at the ecoregion scale, richness responds positively to coral reef area, highlighting potentially huge global biodiversity losses with coral decline. Improved conservation outcomes require management frameworks, informed by hierarchical monitoring, that cover differing site- and regional-scale processes across diverse taxa, including attention to invertebrate species, which appear disproportionately threatened by warming seas
Connectivity modelling of the coral reef ecosystem
No full textIn science there has been a growing focus on networks as a way of understanding complex systems. Nowhere is this more apparent than in marine ecology where strong currents driven by wind, tide and oceanic flows can move larval particles vast distances. The networks created between source and recruitment sites are often complex and large. This capacity has not been adequately addressed in the modelling and conservation literature. This thesis addresses the role of graph theory in advancing applied and pure marine ecology from structural descriptions to conservation planning. Chapter 2 identified the network structure of the Great Barrier Reef as generated by hydrodynamic modelling and Lagrangian particle transfer. We discovered that passive particle dispersal in the Great Barrier Reef forms a topology called “small world”. Small world topology is defined by the capacity of sparsely connected networks to remain comparatively small in their diameter (defined as the minimum number of links between the furthest vertices). We also compared the Great Barrier Reef network to a range of other topologies from simple lattices to intricate scale free graphs. In chapter 3, we described the impact that various dispersal topologies have on the metapopulation persistence of marine species. The stochastic metapopulation model developed by Drechsler (Drechsler M (2009) Predicting metapopulation lifetime from macroscopic network properties. Mathematical Biosciences, 218, 59-71) was adapted to explicitly incorporate graph theory metrics. This work highlighted the importance of topology on the metapopulation dynamics which will be overlooked by researchers using simple diffusion models to represent dispersal. In particular we discovered that networks with clusters (groups of highly connected populations also known as hubs) were more persistent across a range of extinction and colonisation rates. Enhancing metapopulation persistence is a desired outcome of conservation planning so understanding what effect the topology has on optimal reserve placement is critical. In chapter 4 we optimised the metapopulation mean life time, described in chapter 3, by reconfiguring the reserve design. These simulations were based on a variety of network topologies. We found that the optimal persistence of a metapopulation is best achieved by choosing sites in well connected clusters. We also discovered that additional reserves should then be allocated to sites that are relatively isolated from the main clusters. From a conservation perspective, metapopulations, that are predominantly clustered (e.g. having a small world topology), have an increased persistence when sites are protected using knowledge of dispersal topology. While using hydrodynamic models to inform the network structure can be instructive, the reality is that larval transfer between populations is only part of the recruitment process. Issues such as settlement mortality and interspecies competition are highly variable and difficult to assess directly. Chapter 5 utilises population genetics to discover the parental identity of successful recruits. Using the differences in microsatellites loci, population compositions can be compared and measures of similarity generated. We use this methodology and discovered that the genetic network structure of Seriatopora hystrix coral has a small world topology. However the collection and processing of samples for population genetic purposes is limited by resources and therefore lacks the coverage of hydrodynamic models. Describing the biodiversity of the marine world requires information on the spatial assemblage of clusters. These clusters can be defined in terms of genetic similarity or functionally described by oceanography. In chapter 6 we described a conceptual model that compared clusters between disparate networks since the genetic data was sparse while the hydrodynamic models were comprehensive. Using an evidence-based probabilistic framework, this model was able to estimate the likelihood of a particular genetic composition, for a population, from the conditional probabilities derived from a hydrodynamic model. This means the genetic information collected so far can be extended to coral reefs that have not been sampled and, importantly, the model highlighted the coral reefs that are a high priority for future sampling. This thesis utilises graph theory to explore the interconnected world of coral reefs. In particular the Great Barrier Reef was found to have a “small world” topology based on hydrodynamic modelling. We showed that the topology of the dispersal networks has implications for the persistence of the coral and fish metapopulations. We established that optimising the allocation of marine reserves to suit the topological configurations results in the maximum persistence of a metapopulation. We recognised the limitations of hydrodynamic modelling to describe the recruitment process and incorporated population genetics as a measure of coral reef interconnectivity. We discovered that, despite the limited coverage, the genetic network of the coral Seriatopora hystrix also had a small world topology. To help complete the description of the S. hystrix metapopulation structure we combined the genetic and hydrodynamic network information to create a conceptual model that described the cluster configuration. Overall this thesis highlights that the topological character of dispersal networks is highly influential on marine metapopulation dynamics and associated conservation planning. It develops some tools and ideas that help to describe, understand and potentially manage that complexity
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