Marine hotspots of activity inform protection of a threatened community of pelagic species in a large oceanic jurisdiction in the South Atlantic

Remote oceanic islands harbour unique biodiversity, especially of species that rely on pelagic resources around their breeding islands. Identifying marine areas used by such species is important to reduce or limit threats that may put these species at risk. The Tristan da Cunha group of islands in the South Atlantic Ocean hosts several endemic and globally threatened seabirds and pinnipeds; how they use the waters surrounding the islands must be considered when planning industrial activities in the entire Exclusive Economic Zone (EEZ). We identified hotspots of activity by collating animal tracking data from nine breeding seabirds and one marine mammal to inform marine management in the Tristan da Cunha EEZ. To detect statistically significant areas of concentrated activity, we calculated the time-spent-in-area that tracked individuals (breeding adults) of 10 focal species (mainly breeding adults of nine seabirds and adult female Subantarctic fur seals Arctocephalus tropicalis) invested in a grid of regular 10 × 10 km cells within the EEZ, for each of four seasons to account for temporal variability in space use. Applying a spatial aggregation statistic over these grids by each species we detected areas that are used more than expected by chance. Most of the activity hotspots were either within 100 km of the islands or were associated with seamounts being spatially constant across several seasons. Moreover, some species spend a large proportion of their time-at-sea inside the EEZ during certain breeding stages, rendering the sites we identified critical for their fitness. Our approach provides a simple and effective tool to highlight important areas for pelagic biodiversity that will benefit Tristan da Cunha’s conservation planning and marine management strategies

Marine hotspots of activity inform protection of a threatened community of pelagic species in a large oceanic jurisdiction in the South Atlantic

Remote oceanic islands harbour unique biodiversity, especially of species that rely on pelagic resources around their breeding islands. Identifying marine areas used by such species is important to reduce or limit threats that may put these species at risk. The Tristan da Cunha group of islands in the South Atlantic Ocean hosts several endemic and globally threatened seabirds and pinnipeds; how they use the waters surrounding the islands must be considered when planning industrial activities in the entire Exclusive Economic Zone (EEZ). We identified hotspots of activity by collating animal tracking data from nine breeding seabirds and one marine mammal to inform marine management in the Tristan da Cunha EEZ.To detect statistically significant areas of concentrated activity, we calculated the time-spent-in-area that tracked individuals (breeding adults) of 10 focal species (mainly breeding adults of nine seabirds and adult female Subantarctic fur seals Arctocephalus tropicalis) invested in a grid of regular 10 × 10 km cells within the EEZ, for each of four seasons to account for temporal variability in space use. Applying a spatial aggregation statistic over these grids by each species we detected areas that are used more than expected by chance. Most of the activity hotspots were either within 100 km of the islands or were associated with seamounts being spatially constant across several seasons. Moreover, some species spend a large proportion of their time-at-sea inside the EEZ during certain breeding stages, rendering the sites we identified critical for their fitness. Our approach provides a simple and effective tool to highlight important areas for pelagic biodiversity that will benefit Tristan da Cunha’s conservation planning and marine management strategies.</p

Habitat modelling of tracking data from multiple marine predators identifies important areas in the Southern Indian Ocean

International audienc

Habitat modelling of tracking data from multiple marine predators identifies important areas in the Southern Indian Ocean

International audienc

Habitat modelling of tracking data from multiple marine predators identifies important areas in the Southern Indian Ocean

AIM : The distribution of marine predators is driven by the distribution and abundance of their prey; areas preferred by multiple marine predator species should therefore indicate areas of ecological significance. The Southern Ocean supports large populations of seabirds and marine mammals and is undergoing rapid environmental change. The management and conservation of these predators and their environment relies on understanding their distribution and its link with the biophysical environment, as the latter determines the distribution and abundance of prey. We addressed this issue using tracking data from 14 species of marine predators to identify important habitat. LOCATION : Indian Ocean sector of the Southern Ocean. METHODS : We used tracking data from 538 tag deployments made over a decade at the Subantarctic Prince Edward Islands. For each real track, we simulated a set of pseudo‐tracks that allowed a presence‐availability habitat modelling approach that estimates an animal's habitat preference. Using model ensembles of boosted regression trees and random forests, we modelled these tracks as a response to a set of 17 environmental variables. We combined the resulting species‐specific models to evaluate areas of mean importance. RESULTS : Real tracking locations covered 39.75 million km2, up to 7,813 km from the Prince Edward Islands. Areas of high mean importance were located broadly from the Subtropical Zone to the Polar Frontal Zone in summer and from the Subantarctic to Antarctic Zones in winter. Areas of high mean importance were best predicted by factors including wind speed, sea surface temperature, depth and current speed. MAIN CONCLUSIONS : The models and predictions developed here identify important habitat of marine predators around the Prince Edward Islands and can support the large‐scale conservation and management of Subantarctic ecosystems and the marine predators they sustain. The results also form the basis of future efforts to predict the consequences of environmental change.A National Research Foundation (NRF) SANCOR grant to R.R.R. (94916), NRF SANAP grants to M.N.B., R.J.M.C. (SNA103359), P.J.N.d.B., P.G.R. and P.A.P. (SNA2005060800001), and a Scientific Committee on Antarctic Research (SCAR) Fellowship to R.R.R.http://wileyonlinelibrary.com/journal/ddihj2019Mammal Research InstituteZoology and Entomolog

Habitat model forecasts suggest potential redistribution of marine predators in the southern Indian Ocean

International audienceAim: Climate change will likely lead to a significant redistribution of biodiversity inmarine ecosystems. We examine the potential redistribution of a community of marinepredators by comparing current and future habitat distribution projections. Weexamine relative changes among species, indicative of potential future community-levelchanges and consider potential consequences of these changes for conservationand management.Location: Southern Indian Ocean.Methods: We used tracking data from 14 species (10 seabirds, 3 seals and 1 cetacean,totalling 538 tracks) to model the habitat selection of predators around thePrince Edward Islands. Using random forest classifiers, we modelled habitat selectionas a response to a static environmental covariate and nine dynamic environmental covariates obtained from eight IPCC-classclimate models. To project the potentialdistribution of the predators in 2071–2100,we used climate model outputs assumingtwo greenhouse gas emission scenarios: RCP 4.5 and RCP 8.5.Results: Analogous climates are projected to predominantly shift to the southeast andsouthwest. Species’ potential range shifts varied in direction and magnitude, but overallshifted slightly to the southwest. Despite the variable shifts among species, currentspecies co-occurrencepatterns and future projections were statistically similar.Our projections show that at least some important habitats will shift out of nationalwaters and marine protected areas by 2100, but important habitat area will increasein the Convention on the Conservation of Antarctic Marine Living Resources Area.Predicted areas of common use among predators decreased north of the islands andincreased to the south, suggesting that multiple predator species may use southerlyhabitats more intensively in the future. Consequently, Southern Ocean managementauthorities could implement conservation actions to partially offset these shifts.Main conclusions: Overall, we predict that marine predator biodiversity in the southernIndian Ocean will be redistributed, with ecological, conservation and managementimplications

Habitat model forecasts suggest potential redistribution of marine predators in the Southern Indian ocean

AIM : Climate change will likely lead to a significant redistribution of biodiversity in marine ecosystems. We examine the potential redistribution of a community of ma-rine predators by comparing current and future habitat distribution projections. We examine relative changes among species, indicative of potential future community- level changes and consider potential consequences of these changes for conservation and management. LOCATION : Southern Indian Ocean. METHODS : We used tracking data from 14 species (10 seabirds, 3 seals and 1 ceta-cean, totalling 538 tracks) to model the habitat selection of predators around the Prince Edward Islands. Using random forest classifiers, we modelled habitat selection as a response to a static environmental covariate and nine dynamic environmental covariates obtained from eight IPCC-class climate models. To project the potential distribution of the predators in 2071–2100, we used climate model outputs assuming two greenhouse gas emission scenarios: RCP 4.5 and RCP 8.5. RESULTS : Analogous climates are projected to predominantly shift to the southeast and southwest. Species’ potential range shifts varied in direction and magnitude, but over-all shifted slightly to the southwest. Despite the variable shifts among species, cur-rent species co-occurrence patterns and future projections were statistically similar. Our projections show that at least some important habitats will shift out of national waters and marine protected areas by 2100, but important habitat area will increase in the Convention on the Conservation of Antarctic Marine Living Resources Area. Predicted areas of common use among predators decreased north of the islands and increased to the south, suggesting that multiple predator species may use southerly habitats more intensively in the future. Consequently, Southern Ocean management authorities could implement conservation actions to partially offset these shifts. MAIN CONCLUSIONS : Overall, we predict that marine predator biodiversity in the south-ern Indian Ocean will be redistributed, with ecological, conservation and management implications.WWF-UK; Scientific Committee on Antarctic Research; National Research Foundation.http://www.wileyonlinelibrary.com/journal/ddidm2022Mammal Research InstituteZoology and Entomolog

Habitat model forecasts suggest potential redistribution of marine predators in the southern Indian Ocean

Aim: Climate change will likely lead to a significant redistribution of biodiversity in marine ecosystems. We examine the potential redistribution of a community of marine predators by comparing current and future habitat distribution projections. We examine relative changes among species, indicative of potential future community-level changes and consider potential consequences of these changes for conservation and management. Location: Southern Indian Ocean. Methods: We used tracking data from 14 species (10 seabirds, 3 seals and 1 cetacean, totalling 538 tracks) to model the habitat selection of predators around the Prince Edward Islands. Using random forest classifiers, we modelled habitat selection as a response to a static environmental covariate and nine dynamic environmental covariates obtained from eight IPCC-class climate models. To project the potential distribution of the predators in 2071–2100, we used climate model outputs assuming two greenhouse gas emission scenarios: RCP 4.5 and RCP 8.5.Results: Analogous climates are projected to predominantly shift to the southeast and southwest. Species’ potential range shifts varied in direction and magnitude, but overall shifted slightly to the southwest. Despite the variable shifts among species, current species co-occurrence patterns and future projections were statistically similar. Our projections show that at least some important habitats will shift out of national waters and marine protected areas by 2100, but important habitat area will increase in the Convention on the Conservation of Antarctic Marine Living Resources Area. Predicted areas of common use among predators decreased north of the islands and increased to the south, suggesting that multiple predator species may use southerly habitats more intensively in the future. Consequently, Southern Ocean management authorities could implement conservation actions to partially offset these shifts. Main conclusions: Overall, we predict that marine predator biodiversity in the southern Indian Ocean will be redistributed, with ecological, conservation and management implications.</p