Functional rather than structural connectivity explains grassland plant diversity patterns following landscape scale habitat loss

Adam Kimberley,Patricia Krickl,Jan Plue,Olivier Honnay,Peter Poschlod,Danny Hooftman,Jessica Lindgren,Sara A O Cousins,Anna Traveset,James M Bullock

doi:10.1007/s10980-020-01138-x

Abstract

ContextFunctional connectivity is vital for plant species dispersal, but little is known about how habitat loss and the presence of green infrastructure interact to affect both functional and structural connectivity, and the impacts of each on species groups.ObjectivesWe investigate how changes in the spatial configuration of species-rich grasslands and related green infrastructure such as road verges, hedgerows and forest borders in three European countries have influenced landscape connectivity, and the effects on grassland plant biodiversity.MethodsWe mapped past and present land use for 36 landscapes in Belgium, Germany and Sweden, to estimate connectivity based on simple habitat spatial configuration (structural connectivity) and accounting for effective dispersal and establishment (functional connectivity) around focal grasslands. We used the resulting measures of landscape change to interpret patterns in plant communities.ResultsIncreased presence of landscape connecting elements could not compensate for large scale losses of grassland area resulting in substantial declines in structural and functional connectivity. Generalist species were negatively affected by connectivity, and responded most strongly to structural connectivity, while functional connectivity determined the occurrence of grassland specialists in focal grasslands. Restored patches had more generalist species, and a lower density of grassland specialist species than ancient patches.ConclusionsProtecting both species rich grasslands and dispersal pathways within landscapes is essential for maintaining grassland biodiversity. Our results show that increases in green infrastructure have not been sufficient to offset loss of semi-natural habitat, and that landscape links must be functionally effective in order to contribute to grassland diversity.

Highlights

Habitat loss due to land use change is a key driver of global plant biodiversity declines (Foley et al 2005; Newbold et al 2015; Auffret et al 2018)
Traveset Institut Mediterrani d’Estudis Avancats, CSIC-UIB, 07190-Esporles Mallorca, Balearic Islands, Spain species were negatively affected by connectivity, and responded most strongly to structural connectivity, while functional connectivity determined the occurrence of grassland specialists in focal grasslands
Restored patches had more generalist species, and a lower density of grassland specialist species than ancient patches. Protecting both species rich grasslands and dispersal pathways within landscapes is essential for maintaining grassland biodiversity

Summary

Introduction

Habitat loss due to land use change is a key driver of global plant biodiversity declines (Foley et al 2005; Newbold et al 2015; Auffret et al 2018). I.e. reductions in the extent to which the landscape facilitates the movement of species (Taylor et al 1993; Auffret et al 2017) threatens grassland biodiversity, since plant populations in small grassland fragments are less likely to be rescued from local extinction through immigration from neighbouring populations (Eriksson 1996; Evju et al 2015; Hooftman et al 2015; Aguilar et al 2019; Damschen et al 2019)

Objectives

Methods

Results

Conclusion