ABSTRACT
Kelps are canopy-forming brown seaweed sustaining critical ecosystem services in coastal habitats, including shelter, nursery grounds, and providing food resources to a myriad of associated species. This study modeled the fundamental niche of Laminaria abyssalis along the Brazilian continental margin, an endemic species of the South Atlantic, to anticipate potential distributional range shifts under two contrasting scenarios of future environmental changes (RCP2.6 and RCP8.5). The model for fundamental niche predictions considering the "present scenario" has shown a wider potential area than the realized niche (i.e., the area where the species actually occurs) along the Brazilian coast. In both future scenarios, the models have shown niche erosion on the northern portion of the Brazilian coast and niche gains towards the south. In both scenarios, L. abyssalis populations tend to shift to deeper regions of the reef. The restricted range of occurrence (33,000 km2), intense anthropic activities along these beds (e.g., trawling fisheries, oil/gas mining, or removal for agricultural purposes) acting synergically with global warming, may drive this ecosystem to collapse faster than kelp species' ability to adapt. We propose to classify L. abyssalis as Endangered - (EN) under IUCN criteria, and highlight that long-term monitoring of kelp beds is an urgent need to develop effective conservation initiatives to protect such rare and invaluable ecosystem.
Subject(s)
Kelp , Brazil , Ecosystem , Fisheries , Global WarmingABSTRACT
Diet of juvenile mutton Lutjanus analis, dog Lutjanus jocu and lane Lutjanus synagris snappers were studied in the tropical Brazilian estuarine system of the Piraquê-açú and Piraquê-mirim Rivers to determine how these species share the resources in this restricted space. The three species prey principally upon Peracarida (L. synagris: relative importance index I(RIc) = 29%), Natantia (L. analis and L. synagris: I(RIc) = 39 and 38%, respectively), Reptantia (L. analis and L. jocu: I(RIc) = 28 and 43%, respectively) and Teleostei (L. jocu: I(RIc) = 24%). The three species use estuaries as nursery habitats but food overlap was not biologically significant due to a combination of interspecific differences in size, spatial distribution, microhabitat preferences and seasonal patterns of abundance and prey choice. Large marine protected areas incorporating essential habitats for all life stages are suggested to be the best tool for the management of these economically important species.
