Popul Ecol DOI 10.1007/s10144-017-0579-0 ORIGINAL ARTICLE Resource use by the dryad butterfly is scale-dependent Konrad Kalarus1 · Piotr Nowicki1 Received: 12 July 2016 / Accepted: 5 April 2017 © The Author(s) 2017. This article is an open access publication Abstract The factors shaping the ways in which animals that small-scale studies provide useful information about use resources are a key element of conservation biology, species ecology and behavior, especially if conducted in but ecological studies on resource use typically neglect to multiple habitats. consider how the study’s spatial scale may have affected the outcomes. We used the dryad butterfly, inhabiting Keywords Habitat selection · Landscape complexity · xerothermic grassland and wet meadow, to test for differ- Landscape management · Multi-scale research · Spatial ences in its resource use at two scales–habitat patch and scale · Species conservation landscape. Based on records of plant species composition from random points within four habitat patches and from points in 53 patches along surveyed transects, we compared Introduction the microhabitat preferences of the butterfly on the patch scale, and species occurrence and abundance patterns on Assessing the key factors shaping resource use by species the landscape scale. We distinguished four main groups is a basic task of conservation biology (WallisDeVries of factors related to vegetation structure which affected et al. 2002; Krauss et al. 2010; Driscoll et al. 2013). Scale the butterfly’s resource use—factors having similar effects is a unifying concept in ecology, and many ecological pro- on both spatial scales, factors operating primarily on one cesses are scale-dependent (Steffan-Dewenter et al. 2002; of the scales considered, factors relevant only on a single Battisti and Fanelli 2015). The majority of ecological stud- spatial scale, and factors operating on both scales but with ies can be classified according to their spatial scale. Stud- effects differing between the two habitat types. We suggest ies on resource use or habitat use by animals can be car- that invertebrates may respond on two spatial levels or on ried out on the habitat patch scale (e.g., Cobbold and Supp only one, and conclude that larger-scale studies can meet 2012; Strausz et al. 2012; Wajnberg et al. 2013; Ginane the challenges of a sophisticated metapopulation approach et al. 2015), landscape scale (Cozzi et al. 2008; Bergerot and can give insight into the habitat characteristics affect- et al. 2011) or the much larger scale of the distribution ing the persistence of species in landscapes. We stress the range of a species (Hughes et al. 2003; Lindman et al. value of large-scale studies on species’ habitat preferences 2015). These different scales require the use of various when planning conservation strategies, while pointing out methods, such as observation of individual behavior (Sla- mova et al. 2011), transect counts (Kalarus and Nowicki 2015), mark-recapture (Schneider et al. 2003; Akeboshi Electronic supplementary material The online version of this et al. 2015), GPS positioning (Calenge et al. 2009) or math- article (doi:10.1007/s10144-017-0579-0) contains supplementary material, which is available to authorized users. ematical modelling (Wajnberg et al. 2013). In the landscape approach, many matrices reflecting landscape heterogene- * Konrad Kalarus ity, landscape fragmentation and landscape connectivity [email protected] can be employed (Símová and Gdulová 2012). The results 1 Institute of Environmental Sciences, Jagiellonian University, obtained with these methods give insight into different Gronostajowa 7, 30-387 Kraków, Poland aspects of animals’ habitat requirements, from individual Vol.:(0123456789)1 3 Popul Ecol preferences to the population and metapopulation levels, (PLH 120,065). The grasslands form a habitat mosaic of and further to the drivers of a species distribution range. wet meadow patches in the Vistula River valley and xero- The factors behind resource use vary with the habi- thermic calcareous grassland patches on hills. The xero- tat type or studied fraction of it, and they are influenced thermic grasslands comprise vegetation of the Festuco- by random parameters such as weather or the time of day Brometea class and thermophilous sandy grasslands of (Dennis and Sparks 2006; Slamova et al. 2011; Wajn- the Festuco-Thymetum serpylli vegetation. The wet mead- berg et al. 2013; Botham et al. 2015). The probability of ows are covered with vegetation of the Molinietalia order, detecting these drivers also depend on the statistical meth- mainly Molinion communities of different quality, and rela- ods and approaches applied (Schippers et al. 2015; Boyce tively humid lowland hay meadows (Kalarus and Nowicki et al. 2016). Crucial preferences and resource use patterns 2015). The landscape-scale study was done in 27 patches of an investigated species may be not detected in stud- of xerothermic grassland and 26 patches of wet meadow ies conducted on a given scale. The larger landscape scale within the grassland complex (Fig. 1, Electronic Supple- can elucidate metapopulation processes but tends to over- mentary Material (ESM) S1). Patch area ranged from 0.066 look specific habitat preferences of individuals (cf. Cozzi to 11.749 ha for wet meadow, and from 0.024 to 3.452 ha et al. 2008; Akeboshi et al. 2015; Schippers et al. 2015). for xerothermic grassland. The typical distance between the On the other hand, patch-scale research reveals these spe- nearest neighboring patches ranged from 100 to 600 m. To cific individual preferences and can help in the planning of examine the influence of vegetation on the dryad’s resource local conservation measures for endangered species in focal use on the patch scale we selected two xerothermic grass- habitat patches, while leaving one in the dark about the lands and two wet meadows (included also in the land- drivers of metapopulation dynamics (cf. Dennis and Sparks scape-scale study) in the core fragment of the species dis- 2006; Slamova et al. 2011). In extreme cases, even good tribution area, in the western part of the meadow complex conservation work on the patch scale may not prevent the (Fig. 1, ESM S1). These patches covered between 0.813 extinction of local populations due to obstruction of disper- and 4.184 ha and were from 100 to 400 m apart. sal processes or declining genetic variation (Driscoll et al. 2013). Study species In our study we used the dryad butterfly (Minois dryas) to investigate how the spatial scale of research affects find- The dryad butterfly has a Euro-Siberian distribution range ings on resource use, and we assessed the relevance of from the northern part of the Iberian Peninsula to Japan these findings for the design of conservation programmes. (Dąbrowski 1999; Kudrna 2002). In Europe it usually The dryad inhabits two contrasting habitat types: xerother- inhabits two contrasting habitat types: Molinietalia wet mic grassland and wet meadow (Buszko and Masłowski meadow and xerothermic grassland with steppe plants 2008; Kalarus and Nowicki 2015). The dryad is a good typical for communities of Festuco-Brometea (Buszko model for studies of habitat use and species colonization and Masłowski 2008). The dryad occurs usually locally processes, as its distribution has recently been spreading in xerothermic and wet habitats. In Poland its occurrence in Poland. As butterflies strongly depend on plant species, has been restricted to the southern part of the country in used by adults as nectar sources or as food plants by larvae, the Kraków region and the Eastern Carpathians, although we took vegetation composition as a predictor of habitat recently the species is spreading in the country (Buszko preference in this group. We tested the effects of vegetation and Masłowski 2008; Warecki and Sielezniew 2008). The characteristics on resource use by the dryad on two spatial dryad is protected under Polish law and listed as a criti- scales: habitat patch and landscape. We wanted to deter- cally endangered species in the Polish Red Data Book of mine which effects can be detected on the two scales, and Animals (Głowaciński and Nowacki 2004). The larval food which are specific to a particular scale. plants include Poaceae grasses mainly Molinia caerulea as well as Festuca rubra, Bromus erectus, Calamagrostis epi- geios and Arrhenatherum elatius. Females do not show any Methods distinct preferences for ovipositing on specific foodplants and drop their eggs on various grasses (Settele et al. 1999; Study area Głowaciński and Nowacki 2004; Buszko and Masłowski 2008). The flight period is from the end of July to the The study was carried out within an extensive grassland beginning of September. With its expanding distribution, complex covering ca. 35 km2, about 8 km south-west of the dryad is a good model for studies of species expansion the centre of the town of Kraków in southern Poland. The and colonization processes, as in the Kraków region, where area is part of the Bielańsko-Tyniecki Landscape Park and its distribution has recently been spreading from a former the Dębnicko-Tyniecki Obszar Łąkowy Natura 2000 Area refugium—the Skołczanka Reserve. Further advantages are 1 3 Popul Ecol Fig. 1 Location and spatial structure of the study area in the Kraków pied by the dryad. Four patches used in the patch-scale study are out- region, southern Poland. Light grey xerothermic grassland patches; lined. Data are presented in the EPSG coordinate reference system dark grey wet meadow patches; bolded boundaries—patches occu- (32,634 – WGS 84 / UTM zone 34 N) that the dryad is a relatively large butterfly, and its flight is and expressed in m −1. Finally, all flowering nectar plant not very fast and easy to follow, which makes it a useful species within a 1.5 m radius of the point were counted object for habitat use studies and investigations using tran- and their ground cover was recorded.