Mobility, habitat selection and population connectivity of the butterfly Lycaena helle in central Sweden

Hanna Modin,Erik Öckinger

doi:10.1007/s10841-020-00254-y

Hanna Modin, Erik Öckinger

Open Access

https://doi.org/10.1007/s10841-020-00254-y

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Abstract

To be able to predict habitat quality and potential distribution of threatened species is key to developing successful conservation strategies for threatened species with fragmented distributions. The aim of this study was to assess factors that limit the local distribution and density of Lycaena helle, an endangered butterfly, in central Sweden, and to estimate its mobility in order to classify local populations according to their importance for the connectivity on a regional level. An additional aim was to test if L. helle habitat quality could be assessed using remotely-sensed data such as laser scanning (LiDAR). We derived potential predictors of L. helle occurrence from laser scanning data and used a resource selection function to assess their predictive power. We used a mark-recapture approach to study L. helle movement and estimate dispersal distances. The probability of occurrence of L. helle increased with higher solar irradiation and was negatively affected by sloping terrain, but the LiDAR data generally had low predictive power. Population density increased with host plant density, but this effect was weak. The mark-recapture study confirmed that L. helle is very sedentary, with a mean movement distance of only 114 m and a maximum of 600 m. The studied population extends over a large network of interconnected linear habitats, which probably facilitates dispersal and thereby population persistence. Our study highlight the importance of a warm micro-climate and of man-made habitats like road verges and power-line corridors for the conservation of L. helle.

Highlights

Loss of biodiversity is a worldwide concern that is driven mainly by habitat degradation and fragmentation (Pimm et al 2014; Saunders et al 1991)
The area was selected because observations on Artportalen indicated that it contains an extant metapopulation of L. helle
The presence of L. helle was unevenly distributed across habitat types (Fig. 2)

Summary

Introduction

Loss of biodiversity is a worldwide concern that is driven mainly by habitat degradation and fragmentation (Pimm et al 2014; Saunders et al 1991). Many specialized butterflies are strongly negatively affected by habitat loss and fragmentation (Öckinger et al 2010), making them a useful model group for studies on the effects of habitat loss and fragmentation on species persistence (Thomas 2005). For species with fragmented distributions, knowledge about the determinants behind patch occupancy and local population densities is key to developing successful conservation. Factors such as resource abundance and vegetation structure can be important (Fleishman et al 2002; Thomas et al 2001). The abundance of essential resources limit the carrying capacity of local populations. Vegetation structure in combination with topography are important determinants of micro-climate, which is a key

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