Complementary Insights From Range Size and Range Structure in Explaining Species Distributions

Abstract

Aim

To assess the relationship between measures of species' range size and range structure, and to analyse how these measures differ in their relationships to species' intrinsic characteristics and external geographic drivers.

Location

Europe.

Taxon

813 vascular plant taxa endemic to Europe.

Methods

We analysed the relationship between two measures of range size (extent of occurrence and area of occupancy) and two of range structure (range cover and expected patch size) using complete occurrence data from the Atlas Florae Europaeae. We used phylogenetically corrected linear mixed models to compare the effect of species' climatic niche breadth and continental land morphology (range-wide elevation heterogeneity, proximity to continental coasts and geographic position of species' ranges) on species' range size and range structure.

Results

The strength and sign of the correlation between different geographic range size and range structure measures varied substantially. In addition, narrow niche breadth and continental land morphology constrained different range size and range structure measures unequally, with the effect sizes varying across individual measures.

Main Conclusions

Geographic range structure metrics are complementary to measures of geographic range size in explaining occurrence patterns, contributing distinct insight to our knowledge of ecological processes. Comparative analysis of patterns of range size and structure can complement our mechanistic understanding of species' distributions.