Demography of the endangered butterfly Euphydryas aurinia (Lepidoptera: Nymphalidae): A case study of populations in sub-Mediterranean dry calcareous grasslands

Jure Jugovic,Sara Zupan,Martina Luznik,Costanza Uboni

doi:10.14411/eje.2018.049

Jure Jugovic, Sara Zupan + Show 2 more

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https://doi.org/10.14411/eje.2018.049

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Abstract

We studied a population of the regionally endangered marsh fritillary butterfly Euphydryas aurinia inhabiting a system of loosely connected dry calcareous grasslands in sub-Mediterranean Slovenia. Our goal was to set the basis for a long-term monitoring of this butterfly in four meadows using mark-release-recapture (MRR). We determined its demographic parameters, dispersal, behaviour and utilization of nectar plants in different quality patches. Total population size was estimated to be approximately 347 males (95% confidence interval: 262-432) and 326 females (95% confidence interval: 250-402), with an unbiased sex ratio. The average lifespans were 6.3 and 8.6 days, respectively. Daily population sizes followed a parabola with marked protandry. Both sexes were relatively highly mobile with both occasionally moving over half a kilometre. The spatial distribution of animals seemed to be associated with patch size, host plant densities and nectar sources, resulting in much higher population densities in the largest patch. Adult behaviour differed between the sexes, with females resting more and flying less than males. Behaviour also changed during daytime and with the progression of the season. Adults were confirmed to be opportunistic feeders, since as many as ten nectar sources were detected. We conclude that demographic parameters differ greatly among regions and habitats, thus conservation aims should be planned accordingly. Although the population studied is apparently in good condition, there are threats that may hamper the long-term persistence of the species in this area: succession, intensification of mowing and overgrazing.

Highlights

The marsh fritillary, Euphydryas aurinia (Rottemburg 1775) (Lepidoptera: Nymphalidae) is listed in the Habitats Directive 92/43 EEC of the European Union, and included as of least concern in the Red List of Butterflies
We studied a population of the regionally endangered marsh fritillary butterfly Euphydryas aurinia inhabiting a system of loosely connected dry calcareous grasslands in sub-Mediterranean Slovenia
Our goal was to set the basis for the long-term monitoring of the allegedly largest Slovenian metapopulation, considering changes in land management during the last 100 years from traditional extensive grazing that preserved open grasslands in the past, towards overgrazing and intensive mowing in some places, or abandonment leading to succession in others

Summary

Introduction

The marsh fritillary, Euphydryas aurinia (Rottemburg 1775) (Lepidoptera: Nymphalidae) is listed in the Habitats Directive 92/43 EEC of the European Union, and included as of least concern in the Red List of Butterflies (van Swaay et al, 2010). Even local extinctions, are reported, especially for populations inhabiting wet meadows in Eastern, and Central Slovenia; even in protected areas and Natura 2000 sites (Čelik, 2015) This species is well studied throughout its entire distribution, which stretches across Europe to temperate Asia (Gorbunov, 2001; Gorbunov & Kosterin, 2003; Tolman & Lewington, 2009) and its demographic parameters differ considerably in different parts of its distribution. It inhabits a wide range of different habitats: e.g. pastures in UK (Asher et al, 2001), hay meadows in central Europe (Anthes et al, 2003; Konvicka et al, 2003), woodland clearings in Scandinavia (Wahlberg et al, 2002a) and Alpine meadows at high altitudes

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