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Changes in invertebrate body size‐distributions that follow loss of habitat‐forming species can potentially affect a range of ecological processes, including predation and competition. In the marine environment, small crustaceans and other mobile invertebrates ('epifauna') represent a basal component in reef food webs, with a pivotal secondary production role that is strongly influenced by their body size‐distribution. Ongoing degradation of reef habitats that affect invertebrate size‐distributions, particularly transformation of coral and kelp habitat to algal turf, may thus fundamentally affect secondary production. Here we explored variation in size spectra of shallow epifaunal assemblages (i.e. the slope and intercept of the linear relationship between log abundance and body size at the assemblage level) across 21 reef microhabitats distributed along an extensive eastern Australian climatic gradient from the tropical northern Great Barrier Reef to cool temperate Tasmania. When aggregated across microhabitats at the site scale, invertebrate body size spectra (0.125–8 mm range) were consistently log‐linear (R2 ranging 0.87–0.98). Size spectra differed between, but not within, major groups of microhabitats, and exhibited little variability between tropical and temperate biomes. Nevertheless, size spectra showed significant tropical/temperate differences in slopes for epifauna sampled on macroalgal habitats, and in elevation for soft coral and sponge habitats. Our results reveal epifaunal size spectra to be a highly predictable macro‐ecological feature. Given that variation in epifaunal size spectra among groups of microhabitats was greater than variation between tropical and temperate biomes, we postulate that ocean warming will not greatly alter epifaunal size spectra directly. However, transformation of tropical coral and temperate macroalgal habitats to algal turfs due to warming will alter reef food web dynamics through redistribution of the size of prey available to fishes. [ABSTRACT FROM AUTHOR]

Aim: To investigate biotic and abiotic correlates of reef‐fish species richness across multiple spatial scales. Location: Tropical reefs around the globe, including 485 sites in 109 sub‐provinces spread across 14 biogeographic provinces. Time period: Present. Major taxa studied: 2,523 species of reef fish. Methods: We compiled a database encompassing 13,050 visual transects. We used hierarchical linear Bayesian models to investigate whether fish body size, reef area, isolation, temperature, and anthropogenic impacts correlate with reef‐fish species richness at each spatial scale (i.e., sites, sub‐provinces, provinces). Richness was estimated using coverage‐based rarefaction. We also tested whether species packing (i.e., transect‐level species richness/m2) is correlated with province‐level richness. Results: Body size had the strongest effect on species richness across all three spatial scales. Reef area and temperature were both positively correlated with richness at all spatial scales. At the site scale only, richness decreased with reef isolation. Species richness was not correlated with proxies of human impacts. Species packing was correlated with species richness at the province level following a sub‐linear power function. Province‐level differences in species richness were also mirrored by patterns of body size distribution at the site scale. Species‐rich provinces exhibited heterogeneous assemblages of small‐bodied species with small range sizes, whereas species‐poor provinces encompassed homogeneous assemblages composed by larger species with greater dispersal capacity. Main conclusions: Our findings suggest that body size distribution, reef area and temperature are major predictors of species richness and accumulation across scales, consistent with recent theories linking home range to species–area relationships as well as metabolic effects on speciation rates. Based on our results, we hypothesize that in less diverse areas, species are larger and likely more dispersive, leading to larger range sizes and less turnover between sites. Our results indicate that changes in province‐level (i.e., regional) richness should leave a tractable fingerprint in local assemblages, and that detailed studies on local‐scale assemblage composition may be informative of responses occurring at larger scales. [ABSTRACT FROM AUTHOR]

Aim Evaluating the effectiveness of marine reserves in achieving conservation goals is challenged by the decadal scales over which biological systems respond following protection. Given that trophic interactions underpin community responses following protection and that complex ecological interactions make responses difficult to identify, quantifying changes in species traits may provide detail missed by traditional diversity measures, including information relevant to ecosystem functioning. We determine whether this is the case by comparing community metrics based on functional traits to taxonomic diversity measures associated with 'no take' marine reserves and partially protected, fished areas along eight degrees of latitude. Location Eighteen 'no take' marine reserves and 14 partially protected, fished areas along the east coast of Australia. Method We use two independent datasets from shallow and deep coastal rocky reefs to analyse trait-based metrics and taxonomic diversity from sites inside reserves to sites in partially protected, fished areas. Results Taxonomic diversity (species diversity and richness) and trait-based multimetrics (functional richness and dispersion) showed no difference with level of protection. Total fish abundance responded positively to protection, but only on shallow reefs. Comparing values of individual functional traits implied a return of larger bodied species of fish in protected areas and an increase in trophic level. The latter was significant on deeper reefs and was strongly correlated with age of protected area. Thus, recovery responses were largely associated with community mean functional trait values, highlighting the value of trait-based approaches for detecting change, when no differences in traditional taxonomic diversity measures were apparent. Main conclusions We empirically demonstrate that functional traits can elucidate early conservation outcomes, when traditional multimetric diversity indices do not distinguish protected and fished communities. Ecologically relevant but sensitive metrics are fundamental to allow information to be incorporated into adaptive management strategies, which often occur on political rather than biological time-scales. [ABSTRACT FROM AUTHOR]

To delineate biogeographical patterns in Galapagos shallow-water reef fauna at regional scales. Galapagos Islands. Fishes and macro-invertebrates were quantitatively censused using underwater visual techniques along more than 500 transects at defined depth strata across the Galapagos archipelago. Data were analysed using multivariate techniques to define regional patterns and identify species typical of different regions. Subtidal communities of fishes and macro-invertebrates on shallow reefs differed consistently in species composition across the Galapagos archipelago, with three major biogeographical groupings: (1) the ‘far-northern area’ containing the islands of Darwin and Wolf, (2) the ‘central/south-eastern area’, including the east coast of Isabela, and (3) the ‘western area’, encompassing Fernandina and western Isabela. In addition, the northern islands of Pinta, Marchena and Genovesa form a separate region in the central/south-eastern area, and Bahia Elizabeth and Canal Bolivar separate from other parts of the western area. The far-northern bioregion is characterized by high fish species richness overall, including a high proportion of species of Indo-Pacific origin. However, very few endemic fishes or species with distributions extending south from Ecuador (‘Peruvian’ species) are present, and the bioregion also possesses relatively low species richness of mobile macro-invertebrate taxa. By contrast, the ‘western’ bioregion possesses disproportionately high numbers of endemic fish taxa, high numbers of cool-temperate Peruvian fish species, and high invertebrate species richness, but very few species of Indo-Pacific origin. The Bahia Elizabeth/Canal Bolivar bioregion possesses more endemic species and fewer species with Peruvian affinities than coasts within the western bioregion. The northern bioregion of Pinta, Marchena and Genovesa represents an overlap zone with affinities to both the far-northern and south-eastern islands. The south-eastern bioregion includes species from a variety of different sources, particularly ‘Panamic’ species with distributions extending north to Central America. On the basis of congruent divisions for reef fish and macro-invertebrate communities, the Galapagos archipelago can be separated into three major biogeographical areas, two of which can be further subdivided into two regions. Each of these five bioregions possesses communities characterized by a distinctive mix of species derived from Indo-Pacific, Panamic, Peruvian and endemic source areas. The conservation significance of different regions is not reflected in counts of total species richness. The regions with the lowest overall fish species richness possess a temperate rather than tropical climate and highest levels of endemism. [ABSTRACT FROM AUTHOR]

Abstract The distributions of 390 taxa of benthic macroinvertebrates collected in forty-eight estuaries and 101 fish species collected in seventy-five Tasmanian estuaries were related to geographical and environmental variables. Distribution patterns for the two taxonomic groups were largely congruent at both between and within-estuary scales. Faunal composition and the number of species collected at a site were primarily related to site salinity, the biomass of seagrass and tidal range. At the broader estuary scale, the distributions of macroinvertebrate and fish assemblages were primarily correlated with the presence of an entrance bar. Species richness varied with geographical location for both macrofauna and fishes, with highest numbers of species occurring in the Furneaux Group, north-eastern Tasmania and south-eastern Tasmania. These patterns primarily reflected differences in estuary type between regions rather than concentrations of locally endemic species. Although the majority of species collected during the study were marine vagrants, they constituted a very low proportion of total animal densities within estuaries. Only four species considered exotic to Tasmania were identifed. Nearly all species recorded from Tasmanian estuaries occurred widely within the state and have also been recorded in south-eastern Australia. Only 1% of estuarine fish species and < 5% of invertebrate species were considered endemic to the state. The generally wide ranges of species around Tasmania were complicated by (i) the absence of most species from the west coast (ii) a small (< 10%) component of species that occurred only in the north-east and Furneaux Group (eastern Bass Strait), and (iii) a few species (< 5%) restricted to other regions. The low number of species recorded from estuaries along the western Tasmanian coast reflected extremely low faunal biomass in that area. This depression in biomass on the west coast was attributed to unusually low concentrations of dissolved nutrients in rivers and dark tannin-stained waters which greatly restricted algal photosynthesis and primary production. [ABSTRACT FROM AUTHOR]

A commentary about the study "Applying Thresholds to Identify Key Biodiversity Areas for Marine Turtles in Melanesia" is presented. The authors mentioned the tradeoffs in developing appropriate key biodiversity area (KBA) criteria. They considered the application of a KBA criteria. They explored the successful use of KBA criteria to marine turtles.