DOI: 10.5061/dryad.2280gb5z1
title: Morphological variability decreases in populations living in less suitable environments and close to the range edges

description: Aim: Geographic range expansion depends on ecological and evolutionary
 processes that may hamper local adaptations in populations living at range
 edges by constraining phenotypic variability. This study investigates the
 spatial patterns of the intraspecific variability of skull traits
 throughout the geographic range of a marsupial from the Brazilian Atlantic
 Forest. We aimed to answer whether the distance from the range edge and
 the environmental suitability explain the geographic variation of
 morphological variability of the species. Location: Atlantic Forest,
 Brazil. Taxon: Marmosops incanus (Didelphimorphia, Didelphidae). Methods:
 We analysed adult specimens deposited in the main biological collections
 in southeastern Brazil. The morphological variability extent and
 integration within populations were characterised by 13 linear measures of
 the skull, using a multivariate approach. Environmental suitability for
 the species’ occurrence was estimated by Ecological Niche Models, using
 climatic and vegetation productivity as predictors and three different
 modelling methods. Distance from the range edge was calculated based on
 the minimum linear distance between populations and the closest range
 limit. We fitted linear regressions and selected the best models that
 explained the spatial variation of morphological variability based on the
 Akaike information criterion. Results: The extent of morphological
 variability of M. incanus is positively correlated with morphological
 integration and increases with local environmental suitability and
 distance from the range edges. However, the relationship between
 morphological variability and environmental suitability depends on the
 niche modelling method. Main conclusions: Unfavourable
 environmental conditions constrain morphological variability within
 populations of the Gray slender opossum and may hamper local adaptation in
 peripheral populations living in less suitable environments. In addition
 to environmental conditions, geographic location of populations also plays
 an important role in phenotypic variability among populations. We stress
 the boundary effect of the species range on the local adaptation of
 peripheral populations and its possible consequences for the range
 expansion dynamics.
description: Please see the README.md document and the metadata.txt located
 within the /data directory for data collection and analysis information.
 More details on methods can be found in the accompanying published
 article: Braz, A.G.; Figueiredo, M.S.L.; Weber, M.M.; Grelle, C.E.V. 2023
 Morphological variability decreases in populations living in less suitable
 environments and close to the range edges. Journal of Biogeography, doi:
 10.1111/jbi.14687
description: All datasets, outputs and codes were created and/or processed in
 R language. Please see the README.md document and the metadata.txt located
 within the /data directory for data collection and analysis information.
 More details on methods can be found in the accompanying published
 article: Braz, A.G.; Figueiredo, M.S.L.; Weber, M.M.; Grelle, C.E.V. 2023
 Morphological variability decreases in populations living in less suitable
 environments and close to the range edges. Journal of Biogeography,
 10.1111/jbi.14687