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.

Increasing the predictive capabilities of ecological models is important for providing solutions to environmental problems. Progress in this direction relies on the understanding of basic ecological processes. Here, I used interaction web models and natural history information to predict the direct and indirect interactions that regulated succession in a relatively unstudied rocky shore assemblage in the northwest Mediterranean. Natural changes in abundance of organisms and general patterns of succession were examined during March 1991–September 1995. It was predicted that limpets enhanced succession by preventing the monopolization of the substratum by filamentous algae, indirectly facilitating the establishment of other colonists, such as the red alga Rissoella verruculosa, cyanobacteria (Rivularia spp.), and barnacles (Chthamalus spp.). This hypothesis was first tested by comparing succession in artificially denuded patches of substratum maintained at reduced densities of herbivores, with similar patches exposed to natural densities. Variability in the effects of limpets was examined in relation to the size of patches and time of clearance. To unravel the pathways of interaction that influenced the outcomes of this long‐term experiment, I manipulated separate components of the assemblage at early and late stages of succession. I tested whether the filamentous algae inhibited the establishment of Rissoella and Rivularia in the absence of limpets, and whether grazers could exert direct positive effects on these algae. I also tested whether the colonization of Rissoella and barnacles under the natural grazing regime could reduce the local abundance of limpets, thereby facilitating the establishment of filamentous algae at later stages of succession. The filamentous algae monopolized the substratum in the experimental absence of limpets, while in the presence of these grazers, Rissoella, Rivularia, and barnacles colonized. The filamentous algae inhibited the establishment of Rissoella (but not that of Rivularia) independently of the presence of limpets, and there was no positive direct effect of these herbivores on Rissoella. Interactions between barnacles and Rissoella were negligible, but these organisms jointly reduced the coverage of Rivularia and the local density of limpets, eventually facilitating the colonization of filamentous algae late in succession. A main implication of the results of this study is that interaction web models integrated with a basic understanding of the mechanisms of interaction and supported by natural history information, may lead to correct predictions of the direct and indirect effects of species and their influence on succession. As an extension of this approach, I have presented a set of general, qualitative models of succession, applicable to different marine benthic habitats. It is argued that making these models more quantitative, through the analysis of specific alternatives to the null hypotheses, could substantially increase our capabilities to understand and predict the dy...

In the Anthropocene, marine ecosystems are rapidly shifting to new ecological states. Achieving effective conservation of marine biodiversity has become a fast‐moving target because of both global climate change and continuous shifts in marine policies. How prepared are we to deal with this crisis? We examined EU Member States Programs of Measures designed for the implementation of EU marine environmental policies, as well as recent European Marine Spatial Plans, and discovered that climate change is rarely considered operationally. Further, our analysis revealed that monitoring programs in marine protected areas are often insufficient to clearly distinguish between impacts of local and global stressors. Finally, we suggest that while the novel global Blue Growth approach may jeopardize previous marine conservation efforts, it can also provide new conservation opportunities. Adaptive management is the way forward (e.g., preserving ecosystem functions in climate change hotspots, and identifying and targeting climate refugia areas for protection) using Marine Spatial Planning as a framework for action, especially given the push for Blue Growth.

Summary1. The stress-gradient hypothesis predicts an increase in the importance and intensity of positive species interactions towards extreme ends of gradients generated by either physical stress or consumer pressure. However, little attention has been devoted to assessing how the co-occurrence of different gradients of stress and variations in the abundance of the benefactor can influence switches in species interactions. 2. On shallow rocky reefs, we assessed shifts in the effects of different covers of Vermetid tube-building gastropods (benefactor) on macroalgae (beneficiary), under experimental conditions generated by crossing a gradient of consumer pressure (sea urchin density) and a gradient of physical stress (sediment deposition). 3. Negative effects of Vermetids on macroalgae in the absence of herbivores switched to positive at intermediate grazing pressure, but sedimentation and benefactor cover determined their intensity. Thus, association with Vermetids provides macroalgae with a refuge from herbivores. When consumer pressure was the greatest, facilitation persisted both at natural and moderately enhanced sedimentation if the benefactor cover was reduced. When the benefactor monopolized space, facilitation was only observed at natural levels of sedimentation. Thus, the relationship between the outcome of the benefactor-beneficiary interaction (expressed as the Relative Interaction Index) and consumer pressure varied from linear to asymptotic or quadratic, according to sedimentation levels and benefactor abundance. 4. Synthesis. These results show that shifts in the direction and intensity of species interactions are regulated by the interplay of biological and physical factors. In addition, they suggest that densitydependent processes are more likely to shape species interactions at extreme ends of gradients of stress.

Aim Biological invasions are among the main threats to biodiversity. To promote a mechanistic understanding of the ecological impacts of non-native seaweeds, we assessed how effects on resident organisms vary according to their trophic level.Location Global.Methods We performed meta-analytical comparisons of the effects of nonnative seaweeds on both individual species and communities. We compared the results of analyses performed on the whole dataset with those obtained from experimental data only and, when possible, between rocky and soft bottoms.Results Meta-analyses of data from 100 papers revealed consistent negative effects of non-native seaweeds across variables describing resident primary producer communities. In contrast, negative effects of seaweeds on consumers emerged only on their biomass and, limited to rocky bottoms, diversity. At the species level, negative effects were consistent across primary producers' response variables, while only the survival of consumers other than herbivores or predators (e.g. deposit/suspension feeders or detritivores) decreased due to invasion. Excluding mensurative data, negative effects of seaweeds persisted only on resident macroalgal communities and consumer species survival, while switched to positive on the diversity of rocky-bottom consumers. However, negative effects emerged for biomass and, in rocky habitats, density of consumers other than herbivores or predators.Main conclusions Our results support the hypothesis that seaweeds' effects on resident biodiversity are generally more negative within the same trophic level than on higher trophic guilds. Finer trophic grouping of resident organisms revealed more complex impacts than previously detected. High heterogeneity in the responses of some consumer guilds suggests that impacts of non-native seaweeds at higher trophic levels may be more invader-and species-specific than competitive effects at the same trophic level. Features of invaded habitats may further increase variability in seaweeds' impacts. More experimental data on consumers' response to invasion are needed to disentangle the effects of nonnative seaweeds from those of other environmental stressors.

Despite the great interest for the role played by resident assemblages in regulating biological invasions, few studies have assessed how these can influence the spread of exotic species that have successfully established or have included more than one trophic level. On shallow rocky reefs, we assessed how the effects of different benthic assemblages on the spread of an invasive alga, Caulerpa racemosa, are influenced by alterations in the density and species composition of the resident sea urchin assemblage. In order to simulate herbivore species loss scenarios, assemblages dominated by different morphological groups of algae (i.e. turfs or encrusting corallines) or experimentally cleared plots (i.e. bare rock) were exposed to grazing by different combinations of species (Arbacia lixula and Paracentrotus lividus) and densities (natural, -50% and -100% of natural densities) of urchins. Algal turfs and encrusting corallines generally facilitated C. racemosa. Manipulating urchins assemblages did not affect the cover and density of fronds of C. racemosa. In contrast, halving the density of P. lividus favoured the penetration of stolons of C. racemosa, consistently among algal assemblages. Other effects of urchins varied among algal assemblages, indicating interactions between trophic levels. In algal turfs, the total removal of urchins caused a decrease in the penetration of stolons, while it enhanced the length of fronds, indicating a shift in the growth form of this clonal plant and, ultimately, a depression of its spreading ability. In bare or encrusting corallines dominated surfaces, the removal of urchins had positive effects on the penetration of stolons and on the length of fronds of C. racemosa, irrespective of one or two species being manipulated and for the intensity of their removal. Our results show that tradeoffs between negative and positive effects of herbivores, varying according to relative densities of species and to the direction and strength of the effects of resident plant assemblages, can influence local rates of spread of C. racemosa. Thus, not only facilitation of exotics by natives can be key in enhancing the spread of exotic species, but it can occur between organisms at different trophic levels. Finally, our findings have important implications for the management of C. racemosa, in view of the progressive domination of shallow rocky reefs by algal turfs

The detection of anthropogenic disturbances requires appropriate sampling design and powerful statistical tests. This study illustrates how simulations of environmental disturbances may be used to improve the capability of any given sampling design to detect impacts of a specified magnitude. Here, real data on the abundance of algae and invertebrates are used to simulate the effects of environmental disturbances on two rocky shores in the northwest Mediterranean. Natural populations were sampled eight times between 1995 and 1996 in mid-shore habitats on each of two shores. Four sites were sampled at each of three different levels on the shore each time. Three replicate quadrats were sampled in each site. This design was rearranged to create two ''Impacted'' and two ''Control'' sites at each level on each shore. The first four times were used as ''Before'' data; the latter four times represented a series of ''After'' data. Two different approaches were used to simulate environmental impacts. The first was based on the methodology developed in the context of Beyond BACI designs, and consisted in altering the mean abundance of organisms of known amounts at the ''Impacted'' sites for the ''After'' series of data. Simulated data were generated by multiplying the real values by random variates obtained from binomial distributions of means 0.8, 0.5, and 0.2, to simulate reductions in mean abundance to 0.8, 0.5, and 0.2, respectively. These data were analyzed using analysis of variance following the logic of Beyond BACI designs. A Monte Carlo procedure was also developed based on the linear model of the Beyond BACI design, using real estimates of spatial and temporal variance of the red alga Rissoella verruculosa. Power of the Before/After vs. Control/ Impact (B ϫ I) interaction was calculated from sets of 1000 simulations under the alternative hypothesis of an impact causing a reduction in mean abundance of the alga to 0.5. Power curves were generated for the B ϫ I interaction using different combinations of number of sites, number of times, and number of replicate plots, thereby providing a direct way of optimizing the sampling design.In most cases impacts were detected as significant changes from before to after the simulated disturbances in the differences between the impacted and control sites. The probability of detecting an impact was not consistent between the two shores, and it also changed in relation to level on the shore. Statistical power was large for several of the tests involved in the detection of the simulated impacts. Sample size was also calculated for different combinations of Type I and Type II errors, indicating that the sample size required to design powerful environmental sampling programs can be maintained within a range of acceptable and logistically feasible sampling efforts for these rocky shores. In some cases it was not possible to proceed with calculation of power and sample size using classical procedures based on non-central F distributions, due to the impossibility of providing an error...

This study focuses on succession of macroalgae in littoral rock pools on the west coast of Italy. Previous studies in this system indicated that either canopy algae or turf-forming algae may dominate late in succession. Priority effects and non-hierarchical interactions have been proposed as possible explanations for these patterns. From previous knowledge on the timing of reproduction and recruitment of the two groups of algae and their interactions, I predicted that: (1) canopy algae would dominate patches of substratum cleared during their main period of recruitment (between April and July); (2) the turf-forming algae, although initially present, would be replaced by canopies in these patches; (3) turf-forming algae would characterise both the early stages of colonisation and the mature assemblage in patches cleared before or after the main period of recruitment of canopy algae, and (4) succession would be more consistent in space (i.e. canalised) in the presence of canopy algae than when the turf-forming plants achieve dominance. These predictions were tested in a multifactorial experiment where patches of substratum were cleared in three different periods (before, during and after the main period of recruitment of canopy algae), on three dates within each period and in two replicate pools in each date. Univariate and multivariate analyses indicated that variability at early stages of colonisation dictated much of the subsequent dynamics in this system. Predictions 1-3 were supported by the results, but only at a gross level of taxonomic resolution. Patterns of colonisation of individual species of turf-forming algae were unpredictable due to large small-scale spatial and temporal variation in abundance. Prediction 4 was not supported by the results. This study indicated that knowledge of the life-histories and ecology of individual populations is crucial to increase the accuracy and precision of ecological models that attempt to predict succession in variable systems.