species distribution OBIS data
Costello & Chaudhary (2017) used data from OBIS to show that marine species richness is higher in the coastal tropics and decreases with depth. The paper reviews what factors have led to species diversification, and how this knowledge informs conservation priorities.
Two representations of species richness were compared to sea surface temperature and productivity. To minimise sampling effort bias, Estimated Species richness (ES50) was calculated as the number of species in 50 random samples from each 5 degree latitude-longitude cell derived from a dataset of 65,000 species distributions from OBIS in 2009 and equal area hexagons from 51,670 species from OBIS in 2015.
Four measures of species richness calculated from the above hexagons, and sea temperature, were plotted with depth. Species richness, calculated for 32,328 species with known depth of occurrence, for 50,000 km2 hexagrids in the depth range 0 – 500 m (interval of 100) and 500 – 9,000 m (interval of 500).
For environmental data see http://gmed.auckland.ac.nz/.
Details in: Costello MJ, Chaudhary C. 2017. Marine biodiversity, biogeography, deep-sea gradients, and conservation. Current Biology 27, R511–R527. http://dx.doi.org/10.1016/j.cub.2017.04.060
species distribution OBIS data
A global analysis of the biogeography of species richness in razor clams (Solenidae) found the number of species was highest in the northern hemisphere, and dipped at the equator with a smaller peak in the southern hemisphere (Saeedi et al. 2016). Thus Chaudhary et al. (2016) reviewed previous studies and found that almost all latitudinal gradients in marine species richness peaked in the northern hemisphere, with a smaller southern hemisphere peak, and dip at the equator. This contradicted the prevailing paradigm that biodiversity peaks at the equator. A response to this paper suggested that the pattern could be affected by sampling bias (Fernandez and Marques 2016). Thus Chaudhary et al. (2017) used data from OBIS to show that indeed sampling bias influenced the gradient. However, this effect was reduced when using gamma (total species in a latitudinal band) over alpha (average species in latitude-longitude cells in a latitudinal band). Furthermore, when adjusted for sampling effort using ES50 index, the pattern was still bimodal with a dip at the equator, but the peaks in richness were equal in both hemispheres. The authors suggest that this may be because temperature is the main cause of the gradient and is getting too hot at the equator for some species.
These analyses would not have been possible without the integration of data across all taxa and geographic locations by OBIS (the full list of resources used is available in supplement info).
- Saeedi, H, Dennis TE, Costello MJ. 2016. Bimodal latitudinal species richness and high endemicity in razor clams (Mollusca). Journal of Biogeography, online. DOI: http://dx.doi.org/10.1111/jbi.12903
- Chaudhary C., Saeedi H., Costello MJ. 2016. Bimodality of latitudinal gradients in marine species richness. Trends in Ecology and Evolution, 31 (9), 670-676. DOI: http://dx.doi.org/10.1016/j.tree.2016.06.001
- Fernandez, M.O. and Marques, A.C. 2016. Diversity of diversities: a response to Chaudhary, Saeedi, and Costello. Trends Ecol. Evol. Published online November 26 2016. http://dx.doi.org/10.1016/j.tree.2016.10.013
- Chaudhary C., Saeedi H., Costello MJ. 2017. Marine Species Richness Is Bimodal with Latitude: A Reply to Fernandez and Marques. Trends in Ecology and Evolution, 31 DOI: http://dx.doi.org/10.1016/j.tree.2017.02.007
Some like it warm? Warm-dwelling species have increased in response to climate change in western/central Europe
Climate Change species abundance OBIS data
The effect of climate change on population abundances are less studied than those on species ranges. This is partly because population abundance data are harder to obtain. Nonetheless, abundance is an interesting variable to study. A species may change in abundance before there are changes in its range; therefore, we may detect climate change impacts on abundance that are not apparent if we just look at range edges. The aim of our study was to study the impacts of climate change on long-term abundance trends, using a broad range of species from all environmental realms. We included time-series data from 22 different communities since the 1980s, including 6 marine datasets collected from the North Sea (phytoplankton, benthic invertebrates and fish). Our test was based on the prediction that warm-adapted species should increase (or decrease less) than cold-adapted ones within each community under climate change. We used the population data to estimate species’ population trends and compiled distribution data (e.g., from GBIF and OBIS) to estimate species’ temperature preferences. We found a mixture of population trends in almost all datasets: many species have decreased, but many species have also increased. On average, temperature preference was positively related to population trends. Although some of the cold-adapted terrestrial species had decreased, more commonly warm-adapted terrestrial species had increased. We found weaker relationships in the marine and freshwater datasets although warm-dwelling marine fish have increased. Attributing changes in species’ abundance to particular drivers is tricky because populations are exposed to many drivers at the same time. By relating population trends to species characteristics (temperature preferences), we show how it is possible to detect the particular effects of climate change on species’ abundances, and how this is useful for comparative analysis of climate change impacts across environmental realms.
Full reference: Diana E. Bowler, Christian Hof, Peter Haase, Ingrid Kröncke, Oliver Schweiger, Rita Adrian, Léon Baert, Hans-Günther Bauer, Theo Blick, Rob W. Brooker, Wouter Dekoninck, Sami Domisch, Reiner Eckmann, Frederik Hendrickx, Thomas Hickler, Stefan Klotz, Alexandra Kraberg, Ingolf Kühn, Silvia Matesanz, Angelika Meschede, Hermann Neumann, Robert O’Hara, David J. Russell, Anne F. Sell, Moritz Sonnewald, Stefan Stoll, Andrea Sundermann, Oliver Tackenberg, Michael Türkay, Fernando Valladares, Kok van Herk, Roel van Klink, Rikjan Vermeulen, Karin Voigtländer, Rüdiger Wagner, Erik Welk, Martin Wiemers, Karen H. Wiltshire & Katrin Böhning-Gaese. 2017. Cross-realm assessment of climate change impacts on species’ abundance trends. Nature Ecology & Evolution 1: 0067 (doi:10.1038/s41559-016-0067)
species distributions OBIS data
Species abundance distributions (SADs) depict the relative abundance of the species present in a community and describe one of the most fundamental patterns of species diversity. In our recent study, we analysed over 100 datasets covering different taxa and habitats, and showed that c. 15% of the SADs were multimodal with strong support, indicating that multimodality is a more common pattern than currently appreciated. We also showed that this pattern is more prevalent for communities encompassing broader spatial scales or greater taxonomic diversity, suggesting that multimodality increases with ecological heterogeneity. Our results emphasize the need for macroecological theories to include multimodality in the range of SADs they predict. Furthermore, differences in SAD shape across different scales provide important insights into the current endeavour of biodiversity scaling. OBIS was an invaluable source of high quality data, including metadata, from where we retrieved 25 datasets that met our selection criteria. Being able to access the data in a centralized repository was instrumental in terms of gathering appropriate data in a timely manner.
Prevalence of multimodal species abundance distributions is linked to spatial and taxonomic breadth. Laura Henriques Antão, Sean R. Connolly, Anne E. Magurran, Amadeu Soares & Maria Dornelas. Global Ecology and Biogeography, 2016. DOI: 10.1111/geb.12532
species composition biodiversity change
The extent to which biodiversity change in local assemblages contributes to global biodiversity loss is poorly understood. 100 time series from biomes across Earth were analysed to see how diversity within assemblages is changing through time. They quantified patterns of temporal alpha diversity, measured as change in local diversity, and temporal beta diversity, measured as change in community composition. Contrary to their expectations, they did not detect systematic loss of a diversity. However, community composition changed systematically through time, in excess of predictions from null models. Heterogeneous rates of environmental change, species range shifts associated with climate change, and biotic homogenization may explain the different patterns of temporal alpha and beta diversity. Monitoring and understanding change in species composition should be a conservation priority.
This study, which appeared in Science, used 80 time series datasets from OBIS.
Dornelas, M.; Gotelli, N.J.; McGill, B.; Shimadzu, H.; Moyes, F.; Sievers, C.; Magurran, A.E. (2014). Assemblage time series reveal biodiversity change but not systematic loss. Science (Wash.) 344: 296-299. DOI 10.1126/science.1248484
ophiuroids deep sea
The deep ocean is the largest and least-explored ecosystem on Earth, and a uniquely energy-poor environment. The distribution, drivers and origins of deep-sea biodiversity remain unknown at global scales. Here we analyse a database of more than 165,000 distribution records of Ophiuroidea (brittle stars), a dominant component of sea-floor fauna, and find patterns of biodiversity unlike known terrestrial or coastal marine realms. Both patterns and environmental predictors of deep-sea (2,000–6,500m) species richness fundamentally differ from those found in coastal (0–20m), continental shelf (20–200m), and upper-slope (200–2,000m) waters. Continental shelf to upper-slope richness consistently peaks in tropical Indo-west Pacific and Caribbean (0–30°) latitudes, and is well explained by variations in water temperature. In contrast, deep-sea species show maximum richness at higher latitudes (30–50°), concentrated in areas of high carbon export flux and regions close to continental margins. We reconcile this structuring of oceanic biodiversity using a species–energy framework, with kinetic energy predicting shallow-water richness, while chemical energy (export productivity) and proximity to slope habitats drive deep-sea diversity. Our findings provide a global baseline for conservation efforts across the sea floor, and demonstrate that deep-sea ecosystems show a biodiversity pattern consistent with ecological theory, despite being different from other planetary-scale habitats.
ocean acidification pteropods
Pteropods, also called sea butterflies, are tiny snails living in the water column that play a critical role in various ecosystems as prey for a variety of predators. There is a great concern about the potential impact of global change – and particularly ocean acidification – on these organisms as they exhibit an external shell, which is sensitive to changes in ocean chemistry. To represent the impact of both ocean acidification and global warming on pteropods, risk indicators have been calculated for three widely spread taxa that are dominant in high latitudes (Limacina helicina), temperate (Limacina retroversa), and warm waters (Creseis spp.). To create the indicators, experimental and observational data on pteropods’ response to global change were coupled with models describing chemical (aragonite saturation state) and physical (temperature) conditions of the ocean at present, in 2030 and 2050, under the “business as usual” carbon dioxide (CO2) emission scenario (RCP 8.5) and the “two degree stabilization” CO2 emission scenario (RCP 4.5). The present results confirm that global change is a very serious threat for high latitude pteropods: by 2050 under the CO2 emissions scenario RCP 8.5, they likely will not be able to thrive in most of the Arctic Ocean and some regions of the Southern Ocean.
OBIS SEAMAP cetaceans
Cetaceans are protected worldwide but vulnerable to incidental harm from an expanding array of human activities at sea. Managing potential hazards to these highly-mobile populations increasingly requires a detailed understanding of their seasonal distributions and habitats. Pursuant to the urgent need for this knowledge for the U.S. Atlantic and Gulf of Mexico, we integrated 23 years of aerial and shipboard cetacean surveys, linked them to environmental covariates obtained from remote sensing and ocean models, and built habitat-based density models for 26 species and 3 multi-species guilds using distance sampling methodology.