Dispersal ability correlates with range size in Amazonian habitat-restricted birds

Abstract

Understanding how species attain their geographical distributions and identifying traits correlated with range size are important objectives in biogeography, evolutionary biology and biodiversity conservation. Despite much effort, results have been varied and general trends have been slow to emerge. Studying species pools that occupy specific habitats, rather than clades or large groupings of species occupying diverse habitats, may better identify ranges size correlates and be more informative for conservation programmes in a rapidly changing world. We evaluated correlations between a set of organismal traits and range size in bird species from Amazonian white-sand ecosystems. We assessed if results are consistent when using different data sources for phylogenetic and range hypotheses. We found that dispersal ability, as measured by the hand-wing index, was correlated with range size in both white-sand birds and their non-white-sand sister taxa. White-sand birds had smaller ranges on average than their sister taxa. The results were similar and robust to the different data sources. Our results suggest that the patchiness of white-sand ecosystems limits species’ ability to reach new habitat islands and establish new populations.

Sensitivity of Tropical Insectivorous Birds to the Anthropocene: A Review of Multiple Mechanisms and Conservation Implications

“…Experimental studies support the inability or reluctance of many tropical forest interior birds to cross even small breaks in forest (Robinson and Sherry, 2012). A revealing exception that helps prove the rule of poor dispersal in these birds comes from species endemic to white sands soils, which constitute natural "islands" of often low nutrient content and stunted vegetation surrounded by more lush rainforest (Capurucho et al, 2020): Birds inhabiting these long-isolated habitat patches tend to be endemic to it, and to disperse well, a trait necessitated by the long-term, natural isolation of these habitat patches (see section natural enemies and trophic cascades below).…”

Landscape configuration of an Amazonian island-like ecosystem drives population structure and genetic diversity of a habitat-specialist bird

“…In contrast, E. ruficeps is more restricted to campina vegetation (Borges et al 2016b). Additionally, E. ruficeps has a lower handwing index than X. atronitens, a trait that was found to be correlated with overall range size in white-sand specialist birds (Capurucho et al 2020b). These differences in habitat use highlight the importance of considering species traits when addressing congruence in biogeographical scenarios (Papadopoulou and Knowles 2016).…”

An introduction to predictive distribution modelling for conservation to encourage novel perspectives

“…Selection pressures driving morphology, such as migratory compared to sedentary life histories, may also play a role in physically limiting dispersal distance (Capurucho et al, 2020;Claramunt et al, 2012;MacPherson et al, 2021;Sheard et al, 2020). Life history strategies also dictate the demographic trends in dispersal; for example, in many species it is the inexperienced young that disperse into new areas away from the territories of their parents (e.g., Florida Scrub Jay - Suh et al, 2020).…”