Absence of Saharan dust influence on the strontium isotope ratios on modern trees from the Bahamas and Turks and Caicos Islands

We report on strontium (87Sr/86Sr) isotope results from 91 modern trees growing on the Bahamas and Turks and Caicos Islands. The average 87Sr/86Sr ratio of 0.709169±0.000010 is consistent with the late Quaternary limestone of the islands and with the modern ocean value. The absence of any detectable influence of 87Sr-enriched Saharan dust is notable, given the known contribution of this material to both past and recent soils of the Caribbean. Our results indicate that the impact of Saharan dust to the modern biosphere of the Bahamian archipelago is at least an order of magnitude less than modeled in currently available strontium isoscapes for the circum-Caribbean. We suggest that the bioavailability of Sr in Saharan dust may be considerably less than previously thought. Nevertheless, further work could usefully be carried out in the Bahamian archipelago on plants with different rooting depths, growing on different soil types and on limestone of different ages. Our results have particular relevance for the refinement of existing strontium isoscapes and the archaeological provenience of artifacts, animals, and people in the circum-Caribbean

Anchialine biodiversity in the Turks and Caicos Islands: New discoveries and current faunal composition

Lying at the southernmost point of the Lucayan Archipelago, the Turks and Caicos Islands are amongst the better studied localities for anchialine cave biodiversity. For nearly five decades, novel invertebrate fauna, comprised primarily of crustaceans, have been collected from these tidally influenced pools – but new findings are always on the horizon. Herein we present new records of crustaceans and annelids from anchialine blue holes and horizontal caves of the Turks and Caicos. These findings include two potentially new species of meiofaunal annelids and a new species of remipede collected from a shallow water cave pool. Our 2019 expedition additionally expands known faunal distributions for several taxa across the Caicos islands, and raises the biodiversity of the region to 35 species, 13 of them considered endemic. This is the first comprehensive faunal list for the anchialine systems in the Caicos Bank

Horizon scanning for potential invasive non-native species across United Kingdom Overseas Territories

Invasive non-native species are recognized as a major threat to island biodiversity, ecosystems, and economies globally. Preventing high-risk invasive non-native species from being introduced is the most cost-effective way to avoid their adverse impacts. We applied a horizon scanning approach to identify potentially invasive non-native species in the United Kingdom Overseas Territories (OTs), ranging from Antarctica to the Caribbean, and from the Pacific to the Atlantic. High-risk species were identified according to their potential for arrival, establishment and likely impacts to biodiversity and ecosystem function, economies and human health. Across OTs, 231 taxa were included on high-risk lists. The highest-ranking species were the Asian green mussel (Perna viridis), little fire ant (Wasmannia auropunctata), brown rat (Rattus norvegicus) and mesquite tree (Prosopis juliflora). Shipping containers were identified as the introduction pathway associated with the most species. The shared high-risk species and pathways identified provide a guide for other remote islands and archipelagos to focus ongoing biosecurity and surveillance aimed at preventing future incursions