Same species and same niche? new insights about South American fur seals distribution using an integrative approach of ecological niche modelling and molecular phylogeny.

GONCALVES L.; BROWNELL JR. R.L.; MAJLUF P.; BONATTO S.; LOPES F.; CRESPO E.A.; OLIVEIRA L.R.

Valparaíso

Congreso; XI CONGRESO DE LA SOCIEDAD LATINOAMERICANA DE ESPECIALISTAS EN MAMÍFEROS ACUÁTICOS; 2016

The South American fur seals (SAFS) have a disjunct distribution that encompasses at least two evolutionarily significant units (ESUs) along the South America, the Peruvian and Uruguayan. The precise data on spatial limits of this species isunknown, mainly in the southernmost colonies in the continent. The influence of limiting factors on its geographic range remains unclear, but the knowledge of such data is essential for the conservation and monitoring of the species. Taking intoaccount the ecological niche modelling (ENM) and phylogeny, we aimed (1) to test if the ESUs present different ecological niches along their distributions, due to their different evolutionary pathways, and (2) to define the marine predictors toassess their habitat suitability. In this context, we sequenced 64 cytochrome-b fragments sampled from the colonies along the distribution range and analysed them with BEAST Bayesian package. Additionally, we used 172 records of SAFS coloniesfrom the scientific literature to perform ENM analysis. The ENMs were delineated following the results of the phylogeny,generated using marine predictors in MaxEnt software and compared with ENMTools. A supported (HPD=0.93) divergenceof 1.05 Mya±0.5 between the Peruvian and Chile-Atlantic clades was found. One MaxEnt ENM was constructed to each clade above mentioned (accuracies>99.6%), resulting in an almost exclusive habitat suitability to each model. The marine predictors with highest relative contribution were ?dissolved oxygen? (47.4% - Peruvian clade) and ?presence of islands? (36.1% - Chile-Atlantic clade). The analysis in ENMtools revealed that ~81-96% of the models show mutually exclusive suitability for Peruvian and Chile-Atlantic clades (I=0.19; D=0.04; explained model RR=0.60). The Peruvian spatial prediction shows a continuous expansion (~1,000 km) of suitable habitat towards the northern border of Peru when compared to the currently IUCN map. This model also predicted some scattered and low-suitability regions into the area that represents the current gap of the species distribution (between 22°S and 42°S). We hypothesize that these areas could be occupied in potential northwards or southwards migrations in response to El Niño or climate changes. The combination of ENM and phylogeny suggests that the ESUS occupy different niches and have different evolutionary pathways. CAPES; CNPq; Society for Marine Mammalogy - Small Grants in Aid of Research 2016; Amneville Zoo