EUROPEAN JOURNAL OF ENTOMOLOGYENTOMOLOGY ISSN (online): 1802-8829 Eur. J. Entomol. 113: 295–301, 2016 http://www.eje.cz doi: 10.14411/eje.2016.036 ORIGINAL ARTICLE Has the currently warming climate affected populations of the mountain ringlet butterfl y, Erebia epiphron (Lepidoptera: Nymphalidae), in low-elevation mountains? MARTIN KONVIČKA 1, 2, JIŘÍ BENEŠ 2, OLDŘICH ČÍŽEK 1, 3, 5, TOMÁŠ KURAS 4 and IRENA KLEČKOVÁ 2 1 Faculty of Sciences, University of South Bohemia, Branisovska 31, 370 05 Ceske Budejovice, Czech Republic; e-mails: [email protected], [email protected] 2 Institute of Entomology, Biology Centre, CAS, Branisovska 31, 370 05 Ceske Budejovice, Czech Republic; e-mails: [email protected], [email protected] 3 Hutur NGO, J. Purkyne 1606, 500 02 Hradec Kralove, Czech Republic 4 Faculty of Sciences, Palacky University, Slechtitelu 11, 783 71 Olomouc, Czech Republic; e-mail: [email protected] 5 Faculty of Environment, Czech University of Life Sciences, Kamycka 961, 165 21 Praha 6 - Suchdol, Czech Republic Key words. Lepidoptera, Nymphalidae, Erebia epiphron, alpine habitats, temperate mountains, climate warming, population structure, demography, timberline Abstract. Climate change scenarios predict losses of cold-adapted species from insular locations, such as middle high mountains at temperate latitudes, where alpine habitats extend for a few hundred meters above the timberline. However, there are very few studies following the fates of such species in the currently warming climate. We compared transect monitoring data on an alpine butterfl y, Erebia epiphron (Nymphalidae: Satyrinae) from summit elevations of two such alpine islands (above 1300 m) in the Jeseník Mts and Krkonoše Mts, Czech Republic. We asked if population density, relative total population abundance and phenol- ogy recorded in the late 1990s (past) differs that recorded early in 2010s (present) and if the patterns are consistent in the two areas, which are separated by 150 km. We found that butterfl y numbers recorded per transect walk decreased between the past and the present, but relative population abundances remained unchanged. This contradictory observation is due to an extension in the adult fl ight period, which currently begins ca 10 days earlier and lasts for longer, resulting in the same total abundances with less prominent peaks in abundance. We interpret this development as desynchronization of annual cohort development, which might be caused by milder winters with less predictable snow cover and more variable timing of larval diapause termination. Although both the Jeseník and Krkonoše populations of E. epiphron are abundant enough to withstand such desynchronization, decreased synchronicity of annual cohort development may be detrimental for innumerable small populations of relic species in mountains across the globe. INTRODUCTION Rising temperatures may particularly imperil cold adapt- Both poleward (Parmesan, 2006; Chen et al., 2011) and ed species inhabiting islets of alpine habitats in mid-alti- uphill (Konvicka et al., 2003; Lenoir et al., 2008; Roth et tude mountains in temperate zones (Franco et al., 2006; al., 2014) shifts in the distributions of species and shifts in Konvicka et al., 2014). Contrary to spacious high-altitude their phenology (Altermatt, 2010; Diamond et al., 2011) habitats found, e.g., in the Alps, the American Rockies or are widely recognised as both evidence and major out- the Pyrenees, mountains at lower altitudes, such as the Her- comes of the ongoing climate change, or global warming. cynian system of Central Europe (Jeník, 1998), have only In human-dominated landscapes, common taxa, including tiny treeless patches on their summits. Species restricted to pests and pathogens, often perform better in tracking fa- such habitat islands, typically relics of a cooler past, may vourable thermal environments, whereas habitat specialists have nowhere to go if the climate warms up and the tim- may lag behind, entrapped in climatically unsuitable areas berline ascends. In addition to the scientifi c and cultural (Warren et al., 2001; Oliver & Morecroft, 2014). These de- value of these species and communities, such isolated relic velopments may imperil the very existence of numerous populations are often genetically distinct as a result of their species, which are losing their habitats. It is predicted that long isolation (Schmitt et al., 2006, 2014; Konvicka et al., as many as 15–35% of global biodiversity may be lost due 2014), sometimes forming endemic taxa at the specifi c or to climate change in the foreseeable future (Thomas et al., subspecifi c level. 2004). Final formatted article © Institute of Entomology, Biology Centre, Czech Academy of Sciences, České Budějovice. An Open Access article distributed under the Creative Commons (CC-BY) license (http://creativecommons.org/licenses/by/4.0/). 295 Konvička et al., Eur. J. Entomol. 113: 295–301, 2016 doi: 10.14411/eje.2016.036 Fig. 1. Map showing the location of the Jeseník and Krkonoše Mts in Europe, and directions of the permanent transects established there to monitor the relative population abundance of Erebia epiphron. Note that the relief of the summit plateaux in these mountains is relatively fl at. Although green in the maps indicates “forest”, the vegetation above ca. 1250 m consists of clumps of dwarf Picea abies (Jeseník Mts) and shrubby Pinus mugo interspersed among Picea abies (Krkonoše Mts). Probably due to the logistic diffi culties of collecting ing its adult phenology and abundance, continued for two long-term data from mountain areas, there is still little fi ve-year periods (1995–1999 and 2009–2013), separated knowledge of the responses of alpine animals to the cur- by a decade-long gap. This allowed the comparison of E. rent climatic warming, even for such model groups as but- epiphron population parameters recorded in the late 1990s terfl ies. Perhaps the best long-term data available to date and early 2010s. During the interim decade, the mean an- has targeted butterfl y communities inhabiting the Sierra nual temperature rose by 1°C in both areas (Halásová et al., de Guadarrama mountains in Spain (maximum altitude: 2007; Kliment et al., 2011), prompting us to ask the fol- 2428 m), where upslope shifts in community composition lowing questions: (1) Did the abundance of the target spe- attributable to climatic warming have been detected (e.g., cies change over time? (2) Were there detectable changes Wilson et al., 2005, 2007). On the Kananaskis Ridge in in the shape of the adult recruitment curve, such as higher Canada, the ascending timberline genetically isolates indi- or lower numbers recorded per transect walk, more or less vidual mountaintop populations (Keyghobadi et al., 2005) prominent peak in adult emergence, etc.? (3) Was there a and desynchronizes their population dynamics (Roland & detectable change in adult phenology, such as an earlier Matter, 2007; Matter et al., 2011). In Britain, Franco et al. adult fl ight in the later, i.e. warmer period? (2006) report loss of low altitude colonies of the alpine METHODS species, Erebia epiphron (Knoch, 1783), whereas higher altitude populations seemed unaffected. These studies, Species and locations studied however, targeted mountain ranges with plenty of space Erebia epiphron (Nymphalidae: Satyrinae), a member of the above the timberline, allowing the alpine species to move species-rich and mostly cold-adapted butterfl y genus Erebia Dal- to a higher altitude. In contrast, very few researchers have man, 1816, is a mountain grasslands species distributed through- targeted “middle high mountains” (cf. Boggs & Murphy, out most European mountains with areas above the timberline, 1997), in which the alpine habitats currently extend above except in Scandinavia and the mountains on the Iberian peninsula and in the southern Balkans, but including mountains in Brit- the timberline for just a few hundred metres, and hence ain and some low mountain ranges in Central Europe (details: can rapidly disappear due to shifts in altitudinal vegeta- Schmitt et al., 2005). Its adults occur during the short mountain tion bands. One exception is the study by Scalercio et al. summer, inhabiting alpine grasslands and reaching high densities (2014), which compares the past and present distribution there (e.g., Kuras et al., 2003; Polic et al., 2014). Females ovi- of Erebia cassioides (Reiner & Hohenwarth, 1792) on the posit singly on thin-bladed grasses (e.g. Nardus stricta, Festuca Pollino Massif on the Apennines in Italy. supina, Avenella fl exuosa); larvae feed both before and after over- This paper reports the results of monitoring a high moun- wintering and their development may span one or two seasons tain butterfl y, the Mountain Ringlet Erebia epiphron ssp. depending on weather conditions (Sonderegger, 2005). silesiana (Meyer et Dür, 1852) in the Jeseník Mts and Of the three Central European populations north of the Alps, one used to inhabit the Harz Mts, Germany (highest summit: Krkonoše Mts in the Czech Republic. These mountains Brocken Mt., 1141 m), but went extinct in the 1950s. The two have only narrow belts of alpine grassland and poor al- remaining populations, both studied here, inhabit the Jeseník Mts, pine zone faunas (cf. Liška & Skyva, 1997; Beneš et al., NE Czech Republic (highest summit: Praděd Mt., 1492 m, alpine 2000). E. epiphron, the only true alpine butterfl y occur- zone area 1050 ha, timberline at ca 1300 m alt.), and the Krkonoše ring there and has been the subject of earlier population