MotivationThe BioTIME database contains raw data on species identities and abundances in ecological assemblages through time. These data enable users to calculate temporal trends in biodiversity within and amongst assemblages using a broad range of metrics. BioTIME is being developed as a community‐led open‐source database of biodiversity time series. Our goal is to accelerate and facilitate quantitative analysis of temporal patterns of biodiversity in the Anthropocene.Main types of variables includedThe database contains 8,777,413 species abundance records, from assemblages consistently sampled for a minimum of 2 years, which need not necessarily be consecutive. In addition, the database contains metadata relating to sampling methodology and contextual information about each record.Spatial location and grainBioTIME is a global database of 547,161 unique sampling locations spanning the marine, freshwater and terrestrial realms. Grain size varies across datasets from 0.0000000158 km2 (158 cm2) to 100 km2 (1,000,000,000,000 cm2).Time period and grainBioTIME records span from 1874 to 2016. The minimal temporal grain across all datasets in BioTIME is a year.Major taxa and level of measurementBioTIME includes data from 44,440 species across the plant and animal kingdoms, ranging from plants, plankton and terrestrial invertebrates to small and large vertebrates.Software format.csv and .SQL.

High sea surface temperatures caused global coral bleaching during [2015][2016]. During this thermal stress event, we quantified within-and among-species variability in bleaching severity for critical habitat-forming Acropora corals. The objective of this study was to understand the drivers of spatial and species-specific variation in the bleaching susceptibility of these corals, and to evaluate whether bleaching susceptibility under extreme thermal stress was consistent with that observed during less severe bleaching events. We surveyed and mapped Acropora corals at 10 sites (N = 596) around the Lizard Island group on the northern Great Barrier Reef. For each colony, bleaching severity was quantified using a new image analysis technique, and we assessed whether small-scale environmental variables (depth, microhabitat, competition intensity) and species traits (colony morphology, colony size, known symbiont clade association) explained variation in bleaching. Results showed that during severe thermal stress, bleaching of branching corals was linked to microhabitat features, and was more severe at reef edge compared with lagoonal sites. Bleaching severity worsened over a very short time-frame (∼1 week), but did not differ systematically with water depth, competition intensity, or colony size. At our study location, within-and among-species variation in bleaching severity was relatively low compared to the level of variation reported in the literature. More broadly, our results indicate that variability in bleaching susceptibility during extreme thermal stress is not consistent with that observed during previous bleaching events that have ranged in severity among globally dispersed sites, with fewer species escaping bleaching during severe thermal stress. In addition, shaded microhabitats can provide a refuge from bleaching which provides further evidence of the importance of topographic complexity for maintaining the biodiversity and ecosystem functioning of coral reefs.

Structurally complex habitats tend to contain more species and higher total abundances than simple habitats. This ecological paradigm is grounded in first principles: species richness scales with area, and surface area and niche density increase with three-dimensional complexity. Here we present a geometric basis for surface habitats that unifies ecosystems and spatial scales.The theory is framed by fundamental geometric constraints among three structure descriptors-surface height, rugosity and fractal dimension-and explains 98% of surface variation in a structurally complex test system: coral reefs. We then show how coral biodiversity metrics (species richness, total abundance and probability of interspecific encounter) vary over the theoretical structure descriptor plane, demonstrating the value of the theory for predicting the consequences of natural and human modifications of surface structure. Main textMost habitats on the planet are surface habitats-from the abyssal trenches to the tops of mountains, from coral reefs to the tundra. These habitats exhibit a broad range of structural complexities, from relatively simple, planar surfaces to highly complex three-dimensional structures. Currently, human and natural disturbances are changing the complexity of habitats faster than at any time in history [1][2][3][4] . Therefore, understanding and predicting the effects of habitat complexity changes on biodiversity is of paramount importance 5 . However, empirical relationships between commonly-used descriptors of structural complexity and biodiversity are .

Global environmental change has the potential to disrupt well established species interactions, with impacts on nutrient cycling and ecosystem function. On coral reefs, fish living within the branches of coral colonies can promote coral performance, and it has been hypothesized that the enhanced water flow and nutrients provided by fish to corals could ameliorate coral bleaching. The aim of this study was to evaluate the influence of small, aggregating damselfish on the health of their host corals (physiology, recovery, and survival) before, during, and after a thermal-bleaching event. When comparing coral colonies with and without fish, those with resident fish exhibited higher Symbiodinium densities and chlorophyll in both field and experimentally-induced bleaching conditions, and higher protein concentrations in field colonies. Additionally, colonies with damselfish in aquaria exhibited both higher photosynthetic efficiency (FV/FM) during bleaching stress and post-bleaching recovery, compared to uninhabited colonies. These results demonstrate that symbiotic damselfishes, and the services they provide, translate into measureable impacts on coral tissue, and can influence coral bleaching susceptibility/resilience and recovery. By mediating how external abiotic stressors influence coral colony health, damselfish can affect the functional responses of these interspecific interactions in a warming ocean.

AbstractStructurally complex habitats tend to contain more species and higher total abundances than simple habitats. This ecological paradigm is grounded in first principles: species richness scales with area, and surface area and niche density increase with three-dimensional complexity. Here we present a geometric basis for surface habitats that unifies ecosystems and spatial scales. The theory is framed by fundamental geometric constraints among three structure descriptors—surface height, rugosity and fractal dimension—and explains 98% of surface variation in a structurally complex test system: coral reefs. We then show how coral biodiversity metrics (species richness, total abundance and probability of interspecific encounter) vary over the theoretical structure descriptor plane, demonstrating the value of the theory for predicting the consequences of natural and human modifications of surface structure.

Rare and cryptic species can be easily missed during ecological surveys of coral communities. This study reveals a disparity in the reported geographic range of a rare species,Echinomorpha nishihirai,between three different sources; none of which are wholly consistent with the available published occurrence records. Discrepancies in the species ranges reported in two comprehensive online databases are greater for rare, compared with common, coral species, suggesting a need for a more cautious treatment of rare species in biogeographic studies.

Hybridization between damselfishes Dascyllus aruanus and D. reticulatus on the Great Barrier Reef Hybridization among closely related species is relatively common in marine fishes that spawn mid-water. Although at least 81 species of tropical coral-reef fish have been reported to hybridize in nature (primarily Chaetodontidae, Pomacanthidae and Labridae), hybridization is thought to be exceedingly rare among benthic-nesting species that engage in pair spawning, such as the Pomacentridae (Montanari et al. 2016). The Pomacentridae include >385 species, most of which form breeding pairs and nest on the benthos. Yet only four Pomacentridae hybrids have been confirmed based on strong molecular evidence (e.g., Yaakub et al. 2006), and only from areas where one or both species are rare, such as degraded habitats and/or geographic zones of overlap. Here we present both morphological and genetic evidence for the first record of hybridization between Dascyllus aruanus and D. reticulatus (Fig. 1). These are small (4-9 cm total length, TL) benthic-nesting fishes that often cohabit small branching coral heads. They display distinct pairing during breeding, vigorously guarding their eggs until hatching. The hybrid was found cohabiting a colony of Pocillopora damicornis with several D. aruanus and D. reticulatus at a depth of 6 m off Lizard Island (14°40¢08 †S, 145°27¢34 †E), Great Barrier Reef, Australia. The hybrid was adult size (6 cm TL) and had coloration and meristic counts intermediate to both D. aruanus and D. reticulatus. Dascyllus aruanus is white with three broad black bars over the head, pectoral fins and anterior to the caudal fin (Fig. 1a). By comparison, D. reticulatus has a tan body and iris, with one thin black bar across the pectoral fins and along the dorsal margin (Fig. 1c). Both species have black pelvic fins, and pale caudal and pectoral fins. The hybrid had a white body with a light spot on the snout, two black bars over the head and pectoral fins, a black bar along the dorsal margin, but no bar across the anterior part of the caudal fin (Fig. 1b). It also had an intermediate number of soft dorsal fin rays and pectoral fin rays (14 and 19, respectively). However, the number of anal fin rays, tubed lateral line scales and gill rakers were identical only to D. reticulatus (14, 18 and 27, respectively). Analysis of a nuclear gene (TMO-4C4) revealed that the hybrid carried haplotypes identical to both parent species with the two lineages distributed evenly within the hybrid genotype. While Pomacentridae hybridization is rarely observed, this record emphasizes the potential for natural hybridization in areas of high abundance and well within geographic distribution limits.