Mismatches between demographic niches and geographic distributions are strongest in poorly dispersed and highly persistent plant species

Jörn Pagel; Martina Treurnicht; William J Bond; Tineke Kraaij; Henning Nottebrock; AnneLise Schutte-Vlok; Jeanne Tonnabel; Karen J Esler; Frank M Schurr

doi:10.1073/pnas.1908684117

Mismatches between demographic niches and geographic distributions are strongest in poorly dispersed and highly persistent plant species

Proc Natl Acad Sci U S A. 2020 Feb 18;117(7):3663-3669. doi: 10.1073/pnas.1908684117. Epub 2020 Feb 6.

Authors

Jörn Pagel¹, Martina Treurnicht^{2

3

4}, William J Bond⁵, Tineke Kraaij⁶, Henning Nottebrock^{7

8}, AnneLise Schutte-Vlok^{9

10}, Jeanne Tonnabel¹¹, Karen J Esler³, Frank M Schurr²

Affiliations

¹ Institute of Landscape and Plant Ecology, University of Hohenheim, 70599 Stuttgart, Germany; jpagel@uni-hohenheim.de.
² Institute of Landscape and Plant Ecology, University of Hohenheim, 70599 Stuttgart, Germany.
³ Department of Conservation Ecology and Entomology, Stellenbosch University, Matieland 7602, South Africa.
⁴ South African Environmental Observation Network, Claremont 7735, South Africa.
⁵ Department of Biological Sciences, University of Cape Town, Rondebosch 7701, South Africa.
⁶ School of Natural Resource Management, Nelson Mandela University, George 6529, South Africa.
⁷ Department of Biology and Microbiology, South Dakota State University, Brookings, SD 57005.
⁸ Plant Ecology, University of Bayreuth, 95447 Bayreuth, Germany.
⁹ Scientific Services, CapeNature, Oudtshoorn 6620, South Africa.
¹⁰ Department of Botany and Plant Biotechnology, University of Johannesburg, Auckland Park 2006, Johannesburg, South Africa.
¹¹ Department of Ecology and Evolution, Le Biophore, University of Lausanne, 1015 Lausanne, Switzerland.

Abstract

The ecological niche of a species describes the variation in population growth rates along environmental gradients that drives geographic range dynamics. Niches are thus central for understanding and forecasting species' geographic distributions. However, theory predicts that migration limitation, source-sink dynamics, and time-lagged local extinction can cause mismatches between niches and geographic distributions. It is still unclear how relevant these niche-distribution mismatches are for biodiversity dynamics and how they depend on species life-history traits. This is mainly due to a lack of the comprehensive, range-wide demographic data needed to directly infer ecological niches for multiple species. Here we quantify niches from extensive demographic measurements along environmental gradients across the geographic ranges of 26 plant species (Proteaceae; South Africa). We then test whether life history explains variation in species' niches and niche-distribution mismatches. Niches are generally wider for species with high seed dispersal or persistence abilities. Life-history traits also explain the considerable interspecific variation in niche-distribution mismatches: poorer dispersers are absent from larger parts of their potential geographic ranges, whereas species with higher persistence ability more frequently occupy environments outside their ecological niche. Our study thus identifies major demographic and functional determinants of species' niches and geographic distributions. It highlights that the inference of ecological niches from geographical distributions is most problematic for poorly dispersed and highly persistent species. We conclude that the direct quantification of ecological niches from demographic responses to environmental variation is a crucial step toward a better predictive understanding of biodiversity dynamics under environmental change.

Keywords: Hutchinsonian niche; biogeography; demography; life-history traits; population dynamics.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Biodiversity
Demography
Ecosystem*
Proteaceae / classification
Proteaceae / growth & development*
South Africa