Of niches and distributions: range size increases with niche breadth both globally and regionally but regional estimates poorly relate to global estimates

Stephan Kambach,Helge Bruelheide,Jean‐Claude Gégout,Niklaus E Zimmermann,Pascal Vittoz,Thomas Wohlgemuth,Harald Pauli,Erik Welk,Stefan Dullinger,Guillaume Decocq,Gunnar Seidler,Jonathan Lenoir,Antoine Guisan,Jens‐Christian Svenning

doi:10.1111/ecog.03495

Abstract

The relationship between species’ niche breadth (i.e. the range of environmental conditions under which a species can persist) and range size (i.e. the extent of its spatial distribution) has mostly been tested within geographically restricted areas but rarely at the global extent. Here, we not only tested the relationship between range size (derived from species’ distribution data) and niche breadth (derived from species’ distribution and co‐occurrence data) of 1255 plant species at the regional extent of the European Alps, but also at the global extent and across both spatial scales for a subset of 180 species. Using correlation analyses, linear models and variation partitioning, we found that species’ realized niche breadth estimated at the regional level is a weak predictor of species’ global niche breadth and range size. Against our expectations, distribution‐derived niche breadth was a better predictor for species’ range size than the co‐occurrence‐based estimate, which should, theoretically, account for more than the climatically determined niche dimensions. Our findings highlight that studies focusing on the niche breadth vs range size relationship must explicitly consider spatial mismatches that might have confounded and diminished previously reported relationships.

Highlights

The niche is a keystone concept in ecology to quantify and to predict a species’ occurrence in space and time (Pulliam 2000, Guisan and Thuiller 2005, Soberón 2007, Colwell and Rangel 2009)
Linear models and variation partitioning, we found that species’ realized niche breadth estimated at the regional level is a weak predictor of species’ global niche breadth and range size
Since a species’ fundamental niche is almost impossible to capture, we hereafter refer to the niche as the realized niche, i.e. the range of abiotic and biotic conditions under which a species occurs (Soberón 2007)

Summary

Introduction

The niche is a keystone concept in ecology to quantify and to predict a species’ occurrence in space and time (Pulliam 2000, Guisan and Thuiller 2005, Soberón 2007, Colwell and Rangel 2009). Plant species’ distributions can be limited by negative interactions with competitors, herbivores and pathogens (Bruelheide and Scheidel 1999, Bütof and Bruelheide 2011, Gaston 2003) Other factors, such as the geographic configuration of specialized habitats and climate stability (Morueta-Holme et al 2013) or the genetic structure and colonization ability of species (Lowry and Lester 2006), were shown to influence plant range sizes. Many of these factors differently affect species’ range boundaries and operate in interaction (Soberón 2007, Gaston 2009), thereby masking potentially significant relationships between niche breadth and range size in individual species. The relationship between niche breadth and range size was shown to possibly result from artifactual effects, at least in some geographic instances (e.g. Mediterranean islands; Lambdon 2008)

Methods

Results

Conclusion