• Energy Research

Background The main goal of this contribution was to define the ecological niche of the guanaco (Lama guanicoe), to describe potential distributional changes, and to assess the relative importance of niche conservatism and divergence processes between the two lineages described for the species (L.g. cacsilensis and L.g. guanicoe). Methods We used maximum entropy to model lineage’s climate niche from 3,321 locations throughout continental Chile, and developed future niche models under climate change for two extreme greenhouse gas emission scenarios (RCP2.6 and RCP8.5). We evaluated changes of the environmental niche and future distribution of the largest mammal in the Southern Cone of South America. Evaluation of niche conservatism and divergence were based on identity and background similarity tests. Results We show that: (a) the current geographic distribution of lineages is associated with different climatic requirements that are related to the geographic areas where these lineages are located; (b) future distribution models predict a decrease in the distribution surface under both scenarios; (c) a 3% decrease of areal protection is expected if the current distribution of protected areas is maintained, and this is expected to occur at the expense of a large reduction of high quality habitats under the best scenario; (d) current and future distribution ranges of guanaco mostly adhere to phylogenetic niche divergence hypotheses between lineages. Discussion Associating environmental variables with species ecological niche seems to be an important aspect of unveiling the particularities of, both evolutionary patterns and ecological features that species face in a changing environment. We report specific descriptions of how these patterns may play out under the most extreme climate change predictions and provide a grim outlook of the future potential distribution of guanaco in Chile. From an ecological perspective, while a slightly smaller distribution area is expected, this may come with an important reduction of available quality habitats. From the evolutionary perspective, we describe the limitations of this taxon as it experiences forces imposed by climate change dynamics.

AbstractAimWe still lack a consensus on the main variables driving changes in migratory strategies. Different hypotheses have been proposed: productivity, energy, environmental heterogeneity, and genetic predisposition. This work takes an integrative view and analyses migrations from a macroecological perspective estimating the extent to which different environmental variables and historic factors influence migratory life histories.LocationGlobal.Time periodCurrent.Major taxa studiedActinopterygian fishes.MethodsUsing public domain museum records, global repositories, and global measures of temperature, productivity, precipitation and heterogeneity, we spatially analysed the distribution of anadromous, catadromous, amphidromous, potamodromous and oceanodromous migratory fish using 1,676 species and compared it to 1,616 non‐migratory fishes. After analysing the individual roles of productivity and temperature in shaping biodiversity, we conducted path analyses including several environmental variables and principal coordinates of phylogenetic structure (PCPS).ResultsThe different migratory strategies are not evenly distributed around the globe and phylogeny is a relevant variable in shaping current patterns. Productivity is positively related to species richness, except for anadromy and potamodromy, for which we observed a unimodal curve. Temperature significantly drives migratory species richness (except for anadromy). The role of environmental heterogeneity, measured as temperature seasonality and annual range, is strongest for anadromous species, which helps explain their skewed distribution towards higher latitudes and why the kinetic energy hypothesis fails in explaining their richness patterns.Main conclusionsOverall, migratory fish richness can be explained by the interaction of multiple variables, such as productivity, temperature, environmental heterogeneity, and the role of phylogeny, but these variables interact differentially in each strategy, diverging most for the anomalous anadromous fishes. Integrating these results into a global framework to better understand the evolutionary and ecological dynamics of migration will help with predicting responses to anthropogenic climate change.