Beta diversity patterns reveal positive effects of farmland abandonment on moth communities

Murilo Dantas De Miranda,Martin F V Corley,Henrique M Pereira,Thomas Merckx

doi:10.1038/s41598-018-38200-3

Abstract

Farmland abandonment and the accompanying natural succession are largely perceived as unwanted amongst many European conservationists due to alleged negative effects on biodiversity levels. Here, we test this assumption by analysing alpha, beta and gamma diversity patterns of macro-moth communities in habitats on an ecological succession gradient, from extensively managed meadows to scrub-encroached and wooded sites. Macro-moths were light-trapped at 84 fixed circular sampling sites arranged in a semi-nested design within the National Park of Peneda-Gerês, NW-Portugal. In total, we sampled 22825 individuals belonging to 378 species. Alpha, beta and gamma diversity patterns suggest that farmland abandonment is likely to positively affect both overall macro-moth diversity and forest macro-moth diversity, and to negatively affect species diversity of non-forest macro-moth species. Our results also show that spatial habitat heterogeneity is important to maintain gamma diversity of macro-moths, especially for rare non-forest species and habitat specialists.

Highlights

Land-use change has been pinpointed as one of the main factors of global biodiversity change[1], reducing species diversity at various spatial scales and modifying species interactions within ecological communities[2,3]
Because abandonment is associated with more advanced stages of ecological succession, our hypothesis is that farmland abandonment positively affects overall moth diversity, but may negatively affect species diversity of early-successional species groups
We admit that some of the variation in local diversity was due to spillover[14] effects and adjacent biotope context, we believe that the number of sampled sites for each habitat type was sufficiently large to allow a relevant, real-landscape representation of the existing variation in local diversity for each habitat type, and this within each of the landscape types differing in relative cover of the three habitat types

Summary

Introduction

Land-use change has been pinpointed as one of the main factors of global biodiversity change[1], reducing species diversity at various spatial scales and modifying species interactions within ecological communities[2,3]. We focus on farmland abandonment, which is a type of land-use change whose effects on biodiversity are currently unresolved. We here test which of both assumptions is correct by analysing diversity patterns of macro-moth communities in three habitat types on a gradient of ecological succession, representing a space-for-time chronosequence of farmland abandonment. Because a comprehensive analysis of these three aspects of diversity is needed to fully understand the biodiversity consequences of farmland abandonment, we compare alpha, beta and gamma diversity levels of macro-moths amongst three habitat types: extensively managed meadows and both scrub-encroached sites and native woodland. Because abandonment is associated with more advanced stages of ecological succession, our hypothesis is that farmland abandonment positively affects overall moth diversity, but may negatively affect species diversity of early-successional species groups. Providing for several successional stages, is known to benefit gamma diversity at the landscape-scale of moths overall[13], we hypothesise that the provision of early-successional biotopes within forest-dominated landscapes is essential both to counter these negative effects for early-successional species groups and to reach high gamma diversity levels at the landscape scale

Objectives

Methods

Conclusion