Species-Dependent Conservation in a SW Atlantic Ecosystem

Abstract

We discuss species conservation in the temperate Extended Shelf System (ESS) of the SW Atlantic, an area the size of the Mediterranean Sea. The ESS is distinctive due to its shallow continental plateau and the predictable Patagonian Shelf-Break Front (PSBF), generated by the interaction of the Brazil and Malvinas currents with the bathymetry of the shelf and slope. The PSBF is a main driving force that sustains species diversity and abundance, including charismatic species of penguins, albatrosses, seals, and whales. From a conservation standpoint, the ESS is vulnerable. An expanding international fishery operates on the shelf and the slope. From 113 regionally red-listed vertebrates, 28% were threatened; sharks and rays being the most affected. Argentina’s coastal MPAs protect mainly breeding colonies of birds and mammals. Three oceanic National Parks protect a submerged plateau and its surrounding southern slope (Namuncurá-Burdwood Bank) and some benthic-pelagic habitats in the Drake Passage. Yet, despite protected places and available management tools, threatened species remain exposed to risks of local extinction. The ESS is here envisioned as a conservation unit, where interventions follow oceanographic function. Conservation effectiveness may be enhanced if focusing on the most endangered groups. Adaptive, dynamic, and ecosystemic management could be combined with seasonal and movable protected sites. Human-forced global warming, but also the sovereignty conflict over the Malvinas Archipelago, pose considerable challenges to this vision.