What if there is no further south to go: Assessing the vulnerability of Nacella species to climate change

In the current context of climate change, southern South America and the Southern Ocean are undergoing profound environmental transformations that impose challenges to marine species. Shifts in species distribution ranges will occur through expansions or contractions of the range edges. Invertebrates such as Nacella spp., that being template-cold water species, will be more vulnerable to increasing temperature and will therefore suffer range contraction as temperatures increase southward. To understand the future of this sensitive group of gastropods, the potential impact of future climate on the distribution ranges of six species of the genus Nacella was studied using ensemble ecological niche models and representative concentration pathway 8.5 scenarios for the years 2050 and 2100. The results indicate that all the species studied will undergo a shift in their distribution in response to the projected changes in climate with a decline in habitat suitability. Particularly, the species will lose suitable areas mainly in the northern edge of their current distribution. Nevertheless, the species may not change their distribution equally. Our study suggests that N. magellanica , N. clypeater , and N. concinna appear to exhibit vulnerability, albeit with potentially lesser impact. Nacella magellanica is the limpet that shows the least distribution change in 2100. Both species, N. clypeater and N. concinna , will move southward while the Antarctic species will expand their distribution to other Antarctic areas. The most significant impact is expected for three Magellanic species ( N. deaurata, N. flammea, and N. mytilina ), currently distributed across the southern tip of South America. With restricted geographical ranges, these species face increased vulnerability to habitat loss as they cannot migrate southward. This comprehensive analysis offers invaluable insights into how Nacella species could tackle the challenges of climate change. The emphasis on specific species ' vulnerabilities and the differential impacts on their distribution enhances our understanding of the potential consequences of climate change in the studied region. Furthermore, it will aid in formulating effective conservation and management strategies to protect Antarctic and sub-Antarctic ecosystems.