Symbiodinium biogeography tracks environmental patterns rather than host genetics in a key Caribbean reef-builder, Orbicella annularis

This is the final version of the article. Available from the Royal Society via the DOI in this record.The physiological performance of a reef-building coral is a combined outcome of both the coral host and its algal endosymbionts, Symbiodinium While Orbicella annularis-a dominant reef-building coral in the Wider Caribbean-is known to be a flexible host in terms of the diversity of Symbiodinium types it can associate with, it is uncertain how this diversity varies across the Caribbean, and whether spatial variability in the symbiont community is related to either O. annularis genotype or environment. Here, we target the Symbiodinium-ITS2 gene to characterize and map dominant Symbiodinium hosted by O. annularis at an unprecedented spatial scale. We reveal northwest-southeast partitioning across the Caribbean, both in terms of the dominant symbiont taxa hosted and in assemblage diversity. Multivariate regression analyses incorporating a suite of environmental and genetic factors reveal that observed spatial patterns are predominantly explained by chronic thermal stress (summer temperatures) and are unrelated to host genotype. Furthermore, we were able to associate the presence of specific Symbiodinium types with local environmental drivers (for example, Symbiodinium C7 with areas experiencing cooler summers, B1j with nutrient loading and B17 with turbidity), associations that have not previously been described.This project was funded primarily by an NERC grant, no. NE/E010393/1 (J.R.S. and P.J.M.), European Union FP7 project Future of Reefs in a Changing Environment (FORCE) under grant agreement no. 244161 (P.J.M. and J.R.S.) and a University of Exeter studentship (E.V.K.)

Comparing spatial conservation prioritization methods with site versus spatial dependency‐based connectivity

Larval dispersal is an important component of marine reserve networks. Two conceptually different approaches to incorporate dispersal connectivity into spatial planning of these networks exist, and it is an open question as to when either is most appropriate. Candidate reserve sites can be selected individually based on local properties of connectivity or on a spatial dependency-based approach of selecting clusters of strongly connected habitat patches. The first acts on individual sites, whereas the second acts on linked pairs of sites. We used a combination of larval dispersal simulations representing different seascapes and case studies of biophysical larval dispersal models in the Coral Triangle region and the province of Southeast Sulawesi, Indonesia, to compare the performance of these 2 methods in the spatial planning software Marxan. We explored the reserve design performance implications of different dispersal distances and patterns based on the equilibrium settlement of larvae in protected and unprotected areas. We further assessed different assumptions about metapopulation contributions from unprotected areas, including the case of 100% depletion and more moderate scenarios. The spatial dependency method was suitable when dispersal was limited, a high proportion of the area of interest was substantially degraded, or the target amount of habitat protected was low. Conversely, when subpopulations were well connected, the 100% depletion was relaxed, or more habitat was protected, protecting individual sites with high scores in metrics of connectivity was a better strategy. Spatial dependency methods generally produced more spatially clustered solutions with more benefits inside than outside reserves compared with site-based methods. Therefore, spatial dependency methods potentially provide better results for ecological persistence objectives over enhancing fisheries objectives, and vice versa. Different spatial prioritization methods of using connectivity are appropriate for different contexts, depending on dispersal characteristics, unprotected area contributions, habitat protection targets, and specific management objectives. Comparación entre los métodos de priorización de la conservación espacial con sitio y la conectividad espacial basada en la dependenci

Integrating larval connectivity into the marine conservation decision-making process across spatial scales.

Larval dispersal connectivity is typically integrated into spatial conservation decisions at regional or national scales, but implementing agencies struggle with translating these methods to local scales. We used larval dispersal connectivity at regional (hundreds of kilometers) and local (tens of kilometers) scales to aid in design of networks of no-take reserves in Southeast Sulawesi, Indonesia. We used Marxan with Connectivity informed by biophysical larval dispersal models and remotely sensed coral reef habitat data to design marine reserve networks for 4 commercially important reef species across the region. We complemented regional spatial prioritization with decision trees that combined network-based connectivity metrics and habitat quality to design reserve boundaries locally. Decision trees were used in consensus-based workshops with stakeholders to qualitatively assess site desirability, and Marxan was used to identify areas for subsequent network expansion. Priority areas for protection and expected benefits differed among species, with little overlap in reserve network solutions. Because reef quality varied considerably across reefs, we suggest reef degradation must inform the interpretation of larval dispersal patterns and the conservation benefits achievable from protecting reefs. Our methods can be readily applied by conservation practitioners, in this region and elsewhere, to integrate connectivity data across multiple spatial scales

Characterization of macrofauna associated with articulated calcareous algae (Corallinaceae, rhodophyta) occurring in a hydrodynamic gradient on the espírito santo state coast, brazil

The aims of this study were to characterize the macrofauna associated with the articulated calcareous algae occurring on a hydrodynamic gradient off the Vitória metropolitan area, Espírito Santo State, Brazil, and to describe its temporal distribution. Physicochemical variables were measured in situ, and samples of sediment, water and phytal were taken from three sites along the coast in August and November 2005 (winter and spring, respectively) and in February and May 2006 (summer and fall, respectively). Twenty random samples were taken from the rocky surface in the lower midlittoral zone at each site, each season. Six species of articulated algae harboring 9,651 animal specimens distributed among 189 taxa were collected. The dominant taxonomic groups were Mollusca, Polychaeta and Crustacea. The main patterns revealed by statistical analysis related to differences in the abundance and richness at the sample sites, as well as to the correlation between the physicochemical variables and community distance matrices, indicating the importance of the physicochemical variables in the differentiation of the communities. Results also indicated that the variable which most influenced the physicochemical and community properties was the hydrodynamic character of the sites: a high level of hydrodynamism resulting in the calcareous algae´s sheltering a lower abundance and diversity of animal species than a lower level one.Os objetivos deste estudo foram caracterizar a macrofauna associada às algas calcárias articuladas num gradiente de hidrodinamismo no litoral da região metropolitana de Vitória, Espírito Santo, Brasil, e descrever a distribuição temporal. Variáveis fisicoquímicas foram medidas in situ, e amostras do sedimento, água e fital foram feitas em três pontos amostrais do litoral em agosto e novembro de 2005 (inverno e primavera, respectivamente) e fevereiro e maio de 2006 (verão e outono, respectivamente). Em cada ponto, e por estação do ano, foram obtidas 20 amostras aleatórias da superfície do costão rochoso na região do mediolitoral inferior. Seis espécies de algas calcárias articuladas foram coletadas e abrigaram 9.651 espécimes animais distribuídos em 189 táxons. Os grupos taxonômicos dominantes foram Mollusca, Polychaeta e Crustacea. Os principais padrões revelados pelas análises estatísticas foram diferenças na abundância e riqueza entre os pontos amostrais e correlação entre as variáveis fisicoquímicas e a comunidade, indicando que os parâmetros fisicoquímicos foram importantes para a caracterização destas. Os resultados indicaram ainda que a variável que mais influenciou as propriedades fisicoquímicas e da comunidade foi o grau de hidrodinamismo: locais com hidrodinamismo elevado permitem que algas calcárias abriguem uma menor abundância e diversidade de espécies animais do que locais com hidrodinamismo elevado

Connectivity and systemic resilience of the Great Barrier Reef

Australia’s iconic Great Barrier Reef (GBR) continues to suffer from repeated impacts of cyclones, coral bleaching, and outbreaks of the coral-eating crown-of-thorns starfish (COTS), losing much of its coral cover in the process. This raises the question of the ecosystem’s systemic resilience and its ability to rebound after large-scale population loss. Here, we reveal that around 100 reefs of the GBR, or around 3%, have the ideal properties to facilitate recovery of disturbed areas, thereby imparting a level of systemic resilience and aiding its continued recovery. These reefs (1) are highly connected by ocean currents to the wider reef network, (2) have a relatively low risk of exposure to disturbances so that they are likely to provide replenishment when other reefs are depleted, and (3) have an ability to promote recovery of desirable species but are unlikely to either experience or spread COTS outbreaks. The great replenishment potential of these ‘robust source reefs’, which may supply 47% of the ecosystem in a single dispersal event, emerges from the interaction between oceanographic conditions and geographic location, a process that is likely to be repeated in other reef systems. Such natural resilience of reef systems will become increasingly important as the frequency of disturbances accelerates under climate change

Climate change threatens the world’s marine protected areas

Marine protected areas (MPAs) are a primary management tool for mitigating threats to marine biodiversity1,2. MPAs and the species they protect, however, are increasingly being impacted by climate change. Here we show that, despite local protections, the warming associated with continued business-as-usual emissions (RCP8.5)3 will likely result in further habitat and species losses throughout low-latitude and tropical MPAs4,5. With continued business-as-usual emissions, mean sea-surface temperatures within MPAs are projected to increase 0.035 °C per year and warm an additional 2.8 °C by 2100. Under these conditions, the time of emergence (the year when sea-surface temperature and oxygen concentration exceed natural variability) is mid-century in 42% of 309 no-take marine reserves. Moreover, projected warming rates and the existing ‘community thermal safety margin’ (the inherent buffer against warming based on the thermal sensitivity of constituent species) both vary among ecoregions and with latitude. The community thermal safety margin will be exceeded by 2050 in the tropics and by 2150 for many higher latitude MPAs. Importantly, the spatial distribution of emergence is stressor-specific. Hence, rearranging MPAs to minimize exposure to one stressor could well increase exposure to another. Continued business-as-usual emissions will likely disrupt many marine ecosystems, reducing the benefits of MPAs

Caribbean-Wide, Long-Term Study of Seagrass Beds Reveals Local Variations, Shifts in Community Structure and Occasional Collapse

The CARICOMP monitoring network gathered standardized data from 52 seagrass sampling stations at 22 sites (mostly Thalassia testudinum-dominated beds in reef systems) across the Wider Caribbean twice a year over the period 1993 to 2007 (and in some cases up to 2012). Wide variations in community total biomass (285 to >2000 g dry m−2) and annual foliar productivity of the dominant seagrass T. testudinum (2000 g dry m−2) were found among sites. Solar-cycle related intra-annual variations in T. testudinum leaf productivity were detected at latitudes > 16°N. Hurricanes had little to no long-term effects on these well-developed seagrass communities, except for 1 station, where the vegetation was lost by burial below ∼1 m sand. At two sites (5 stations), the seagrass beds collapsed due to excessive grazing by turtles or sea-urchins (the latter in combination with human impact and storms). The low-cost methods of this regional-scale monitoring program were sufficient to detect long-term shifts in the communities, and fifteen (43%) out of 35 long-term monitoring stations (at 17 sites) showed trends in seagrass communities consistent with expected changes under environmental deterioration.UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigación en Ciencias del Mar y Limnología (CIMAR