Range size and its ecological correlates among the pteridophytes of Carrasco National Park, Bolivia

Abstract

AbstractAim To identify the factors determining the range size of pteridophytes (ferns and allied plants) in an Andean region.Location Humid eastern Andean slope in Carrasco National Park, Bolivia.Methods I used a macroecological approach to search for correlations of range size to elevation, habitat type, life form, reproductive strategy, the species’ elevational range, and its frequency, among the 473 pteridophyte species recorded in the park.Results Range sizes were smallest at 1800–3500 m elevation and in localized habitats with little disturbance (ravines, ridges), while regularly disturbed habitats (pastures, roadsides) supported widespread species. Families and genera differed with respect to the range sizes of their species, but this pattern was not correlated to any other studied factor and could not be explained. Species with restricted ranges tended to be more frequent in the study area than widespread species. Widespread species tended to have large elevational ranges, implying that they are ecologically more adaptable than localized species. There was no relationship of range size to life form or to the studied reproductive aspects (sexual vs. asexual reproduction, chlorophyllous vs. achlorophyllous spores).Conclusions The above trends were mostly uncorrelated and explained a rather small portion of the observed range size variance. Thus, it is not yet possible to draw a cohesive picture of the factors determining pteridophyte range size. Intriguing questions for future research include the relationship of range size to dispersal, competitive ability, and taxonomic affinity.