Modeling impacts of climate change on the potential habitat of an endangered Brazilian endemic coral: Discussion about deep sea refugia

Abstract

Climate and environmental conditions are determinant for coral distribution and their very existence. When changes in such conditions occur, their effects on distribution can be predicted through species distribution models, anticipating suitable habitats for the subsistence of species. Mussismilia harttii is one of the most endangered Brazilian endemic reef-building corals, and in increasing risk of extinction. Herein, species distribution models were used to determine the present and future potential habitats for M . harttii . Estimations were made through the maximum entropy approach, predicting suitable habitat losses and gains by the end of the 21st century. For this purpose, species records published in the last 20 years and current and future environmental variables were correlated. The best models were chosen according to the Akaike information criterion (AIC) and evaluated through the partial ROC (AUCratio), a new approach which uses independent occurrence data. Both approaches showed that the models performed satisfactorily in predicting potential habitat areas for the species. Future projections were made using the International Panel on Climate Change (IPCC) scenarios for 2100, with different levels of greenhouse gas emission. Representative Concentration Pathways (RCPs) were used to model the Future Potential Habitat (FPH) of M . harttii in two different scenarios: stabilization of emissions (RCP 4.5) and increase of emissions (RCP 8.5). According to the results, shallow waters to the south of the study area concentrate most of the current potential habitats for the species. However, in future scenarios, there was a loss of suitable areas in relation to the Current Potential Habitat (RCP 4.5 46% and RCP 8.5 59%), whereas there is a southward shift of the suitable areas. In all scenarios of FPH, the temperature was the variable with the greatest contribution to the models (> 35%), followed by the current velocity (> 33%) and bathymetry (>29%). In contrast, there is an increase of deep (50–75 m) suitable areas FPH scenarios, mainly in the southern portion of its distribution, at Abrolhos Bank (off Espirito Santo State). These deeper sites might serve as refugia for the species in global warming scenarios. Coral communities at such depths would be less susceptible to impacts of climate change on temperature and salinity. However, the deep sea is not free from human impacts and measures to protect deeper ecosystems should be prioritized in environmental policies for Brazilian marine conservation, especially the Abrolhos Bank, due to its importance for M . harttii .

Predicted Shifts in the Distributions of Atlantic Reef-Building Corals in the Face of Climate Change

“…In that sense, the current niche of M. hispida is smaller than predicted, raising even further concern regarding this species. Other species of Mussismilia that are endemic to Brazil also have narrow suitable niche areas and are at risk of extinction (de Oliveira et al, 2019). Also, it's important to note that even if areas are considered suitable for a reef builder species, this may not reflect in reef formation nor in optimal growth conditions.…”

Evaluation of Shifts in the Potential Future Distributions of Carcharhinid Sharks Under Different Climate Change Scenarios

“…Predicting and mapping the contractions and expansions of suitable areas for threatened and endangered species is critical for monitoring and restoring their natural populations (De Oliveira et al, 2019). Several studies have modeled the potential future distribution of species; however, there are multiple sources of variation and uncertainty in the geographic predictions and their interpretation that are associated with the methodology (Peterson et al, 2018;Alkishe et al, 2020).…”

Composting the Invasive Toxic Seaweed Rugulopteryx okamurae Using Five Invertebrate Species, and a Mini-review on Composting Macroalgae

“…In this sense, some ecosystems which are highly vulnerable to rising temperatures, such as coral reefs and estuaries, can be seriously damaged, producing a punctual void of native algae which is immediately exploited by invasive species [8]. Examples of these processes are the invasions of the Asian brown alga R. okamurae (Fig.…”