Patterns of range size in New Zealand ferns and lycophytes

Abstract

We describe spatial patterns in the geographic ranges of all New Zealand ferns and lycophytes, test if range sizes are correlated with phylogeny, and identify ecological characteristics related to their range sizes. Herbarium records for all species of fern and lycophyte in New Zealand were used to generate distribution maps and estimate range sizes by summing the area of occupied ecological districts. Trait, habitat, biostatus, and distribution data were compiled from the literature and DNA sequence data were obtained for each species. Species’ range sizes varied between 356 km² and the entire country (266 067 km²). The range size frequency distribution for New Zealand ferns was right skewed and bimodal, showing that although most species have small ranges, there is a smaller, core group of very widely distributed species. Larger range sizes were most associated with species that were native, epiphytic, habitat generalists, and which occurred across a large altitudinal extent. The range size of introduced species was positively related to both the number of years since arrival in New Zealand, and the number of global regions they occur in.