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.
Aim We examine fish invasions in the south-eastern Mediterranean as a model system for the invasibility of open coasts and provide perspectives through a review of global marine fish invasions.Location South-eastern Mediterranean (Levant Sea).Methods We compare historical (1990-1994) and modern (2008-2011) trawl surveys from the Mediterranean continental shelf and upper slope of Israel to evaluate the relative abundance and biomass of Indo-Pacific fishes and their impact on diversity and trophic level (TrL). We examine resultant changes in community composition by both univariate and multivariate analyses, and compliment this study with a critical global review of open coast marine fish invasions.Results A staggering 55 Indo-Pacific fish species have established permanent populations in the Mediterranean in the last 142 years, more than any other marine ecosystem. This process is accelerating with 13 of 27 new arrivals having established in the 21st century alone. Invasive fish biomass and abundance proportions in the shallow open coast have doubled in just two decades and today the Levantine ecosystem is dominated by non-native species. This proliferation has resulted in significant declines of some indigenous species, some to near extirpation levels.Main conclusions Here, we show that non-estuarine ecosystems are much more susceptible to large-scale invasion pressures than previously thought. Our results place invasion in the same category with overexploitation, habitat destruction and pollution, processes normally considered as much more critical perturbations to coastal fish communities. We propose that despite these irreversible alterations, invasions have masked overall TrL changes and diversity declines by replacing native fish with invasives of similar ecological position. As species extirpations increase, we anticipate further declines in indigenous biomass, abundance and diversity in the Mediterranean Sea.
Using a temporal-dynamic calibrated Ecosim food web model, we assess the effects of future changes on marine resources and ecosystem conditions of the Israeli Mediterranean continental shelf. This region has been intensely invaded by Indo-Pacific species. The region is exposed to extreme environmental conditions, is subjected to high rates of climate change and has experienced intense fishing pressure. We test the impacts of a new set of fishing regulations currently being implemented, a continued increase in sea temperatures following IPCC projections, and a continued increase in alien species biomass. We first investigate the impacts of the stressors separately, and then we combine them to evaluate their cumulative effects. Our results show overall potential future benefits of fishing effort reductions, and detrimental impacts of increasing sea temperature and increasing biomass of alien species. Cumulative scenarios suggest that the beneficial effects of fisheries reduction may be dampened by the impact of increasing sea temperature and alien species when acting together. These results illustrate the importance of including stressors other than fisheries, such as climate change and biological invasions, in an ecosystem-based management approach. These results support the need for reducing local and regional stressors, such as fishing and biological invasions, in order to promote resilience to sea warming.
Recent decades have seen profound changes in species abundance and community composition. In the marine environment, the major anthropogenic drivers of change comprise exploitation, invasion by nonindigenous species, and climate change. However, the magnitude of these stressors has been widely debated and we lack empirical estimates of their relative importance. In this study, we focused on Eastern Mediterranean, a region exposed to an invasion of species of Red Sea origin, extreme climate change, and high fishing pressure. We estimated changes in fish abundance using two fish trawl surveys spanning a 20-year period, and correlated these changes with estimated sensitivity of species to the different stressors. We estimated sensitivity to invasion using the trait similarity between indigenous and nonindigenous species; sensitivity to fishing using a published composite index based on the species' life-history; and sensitivity to climate change using species climatic affinity based on occurrence data. Using both a meta-analytical method and random forest analysis, we found that for shallow-water species the most important driver of population size changes is sensitivity to climate change. Species with an affinity to warm climates increased in relative abundance and species with an affinity to cold climates decreased suggesting a strong response to warming local sea temperatures over recent decades. This decrease in the abundance of cold-waterassociated species at the trailing "warm" end of their distribution has been rarely documented. Despite the immense biomass of nonindigenous species and the pre-
The ecosystems of the Israeli Mediterranean coast have undergone significant ecological changes in recent decades, caused primarily by the introduction of alien species, fishing and the warming of the waters. Here we used a food-web model representing the continental shelf of the Israeli Mediterranean coast to explore the historical dynamics of the area considering the combined effect of alien species, fishing activities and changes in sea surface temperature and primary productivity. The food-web model was fitted to available time series of data from the early 1990s to 2010 using the temporal dynamic module of the Ecopath with Ecosim modeling approach. An important challenge was to model the numerous alien species inhabiting the Eastern Mediterranean Sea, one of the most invaded marine ecosystems of the world. Historical model simulations satisfactorily matched observed data, especially regarding alien groups. However, lack of data from the pelagic environment limited our ability to compare model output with historical observations. Trophic interactions, climate change and fishing were important factors explaining the historical dynamics of the ecosystem, which showed a degradation pattern over time. Results also highlighted an increasing proportion of alien species in biomass and catch over time, with important effects on the food web. This study represents an important step forward in understanding the changes that are occurring in the Israeli continental shelf ecosystem and the Levantine Sea.
SUMMARY:The spatiotemporal patterns of discards and catch composition of Israeli trawlers were examined using a 4-year (1990-1994), 324 haul dataset. Haul depth was found to be the main grouping variable for hauls, although significant seasonal differences were also found. 28.3% of the total catch was discarded, and there was a 40.1% discard percentage in shallow hauls. According to these figures, annual discards for the Israeli trawl fleet for the study period are estimated at ca. 440 to 700 t. Both the biomass and the number of discarded specimens peaked in summer, as well as the percentage of juvenile fish of commercial species. These findings suggest that a summer moratorium on trawling would reduce discards. The percentage of specimens of Indo-Pacific origin decreased from 51% in depths shallower than 37 m to 24% between 38 and 73 m, and 8% in deeper strata. Discards along the Israeli coast were comparable to those observed elsewhere in the Mediterranean. The findings presented here are the first quantitative account of fish community assemblages in the nearshore waters of the easternmost part of the Mediterranean, and thus provide valuable information for comparisons with more current datasets that are currently being assembled.Keywords: bottom-trawl, Israel, discards, catch composition, Lessepsian migration, fishery management. RESUMEN:Patrones espacio-temporales de la captura y los descartes de pesquería de arrastre mediterránea israelí al inicio de la década de los noventa: perspectivas ecológicas y de conservación. -Se analizaron los patrones espacio-temporales de los descartes y la composición de la captura de la flota de arrastre de Israel utilizando datos de 4 años (1990)(1991)(1992)(1993)(1994), 324 caladas. La profundidad resultó ser el principal factor en la agrupación de las caladas, si bien se encontraron asimismo diferencias significativas entre estaciones. Se descartó el 28.3% de la captura total, alcanzándose el 40.1% en las caladas realizadas en las aguas más someras. Según estos porcentajes, se estimó una captura anual descartada por la flota de Israel en ese período de 440-700 t. La biomasa, el número de ejemplares descartados, así como el porcentaje de juveniles de especies comerciales fue mayor en verano. Estos resultados sugieren que una veda de arrastre en verano favorecería la disminución de la captura descartada. El porcentaje de ejemplares de origen indo-pacífico descendió desde 51% en aguas de una profundidad inferior a 37 m, al 24% entre 38-73 m y al 8% en el estrato más profundo. Los descartes en la costa israelí fueron similares a los observados en otras zonas del Mediterráneo. Se presentan por primera vez resultados cuantitativos relativos a comunidades de las aguas costeras del extremo oriental del Mediterráneo, aportándose información para su comparación con datos más recientes que en la actualidad están siendo obtenidos.Palabras clave: arrastre de fondo, Israel, descartes, composición de la captura, migración lessepsiana, gestión de pesquerías.
Blooms of the invasive ctenophore, Mnemiopsis leidyi, occurred in 2009 along the Mediterranean Sea coasts of Spain and Israel. This voracious zooplanktivore spread throughout the Black Sea basin after its introduction in the early 1980s, throughout northern European coastal waters, and now occurs throughout the Mediterranean Sea. M. leidyi occurred throughout the summer along the entire Catalan Spanish and Israeli coasts in 2009. Those locations had high temperatures (18-26°C) and salinities (37-38) during the blooms. The patterns of abundance of large jellyfish along the Catalan coast were unusual in 2009, with low numbers during July, August, and September when ctenophores were abundant. Small populations of those potential predators and food competitors of M. leidyi could have contributed to the ctenophore bloom. The identity of the ctenophores from Spain and Israel was confirmed as M. leidyi by molecular analysis based on DNA sequencing of the nuclear internal transcribed spacer (ITS) regions. This is the first molecular confirmation of M. leidyi in the Mediterranean Sea. Most ctenophores had an ITS genotype previously found in M. leidyi from other invaded regions (the Black, Azov, and Mediterranean seas), as well as native regions in the United States, suggesting common ancestry. Based on the circulation patterns of Mediterranean surface waters and shipping activities, we conclude that the spread of M. leidyi in the Mediterranean probably resulted from re-introductions by ballast water transport and subsequent distribution by currents. We also conclude that the near-simultaneous blooms in opposite ends of both the Mediterranean basins indicate that M. leidyi is resident around the Mediterranean. We discuss environmental conditions, food, and predators of M. leidyi in both regions that would influence the future effects of this voracious consumer on the pelagic food web of the Mediterranean Sea.
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