Long-term large-scale decline in relative abundances of butterfly and burnet moth species across south-western Germany

Jan Christian Habel,Thomas Schmitt,Werner Ulrich,Michael Ochse,Robert Trusch

doi:10.1038/s41598-019-51424-1

Abstract

Current studies have shown a severe general decline in insect species diversity, their abundance, and a biomass reduction of flying insects. Most of previous studies have been performed at single sites, or were spatially restricted at the landscape level. In this study, we analyse trends of species richness and shifts in species composition of butterflies and burnet moth species across the federal state of Baden-Württemberg in south-western Germany, covering an area of 35,750 km2. The data set consists of 233,474 records and covers a period from 1750 until today. We grouped species according to their species´ specific functional traits and analyse how species with different habitat requirements and behaviour respond to land-use changes over time. Our data document a significant loss of relative abundance for most species, especially since the 1950s until today. Species demanding specific habitat requirements are more seriously suffering under this trend than generalists. This in particular affects taxa adapted to extensively used xerothermic grasslands, bogs or other habitats maintained by traditional low-productivity agricultural practices of the past. Our data indicate large-scale decline in relative abundance of many butterfly and burnet moth species, which happened in particular during the past few decades.

Highlights

Current studies have shown a severe general decline in insect species diversity, their abundance, and a biomass reduction of flying insects
Apart from decreasing species richness and shifts in species composition, recent studies documented a severe reduction in arthropod abundances during the past decades[7]
We analyse long-term and large-scale data on butterflies and burnet moth species that have been collected across the federal state of Baden-Württemberg in south-western Germany, covering a total area of 35,750 km[2]

Summary

Introduction

Current studies have shown a severe general decline in insect species diversity, their abundance, and a biomass reduction of flying insects. Apart from very few studies in which German-wide data sets were used[18,19], most research projects were conducted on single taxa, do represent the situation of a geographically restricted area (i.e. one or some few sites) and mostly cover relatively short periods of time (few years to few decades, represented by two or few time steps)[5,6,8]. This makes most studies assailable, and the explanatory power remains limited and applies to a specific area and/or species.

Methods

Results

Conclusion