Population Structure, Mobility and Habitat Preferences of the Violet ...

Journal

of

Insect

Conservation,

3, 43–52 (1999)

Population structure, mobility and habitat preferences of the violet copper Lycaena helle (Lepidoptera: Lycaenidae) in Western Germany: implications for conservation Klaus Fischer, Burkhard Beinlich and Harald Plachter* University of Marburg, Faculty of Biology, Institute for Nature Conservation, Lahnberge, D-35032 Marburg, Germany Received: 23 March 1998; accepted: 10 August 1998 We describe population structure, mobility and habitat preferences of the butterfly Lycaena helle using a survey of the populations in the Westerwald area (Western Germany) and mark-recapture techniques. Three out of 83 recorded populations were intensively studied in 1995. In all, 1596 individuals (537 females) were uniquely marked. The average adult residence time was 8 days, the maximum 34 days. L. helle is extremely sedentary. Average distances between first and subsequent captures were 37 and 61 meters for males and females respectively. Population-specific differences are interpreted as being caused by the influence of barriers and corridors. The potential for colonization is regarded as poor, and isolated populations seem to be under a higher risk of extinction than other ones. Preferred habitats were abandoned moist meadows with rich aspects of Polygonum bistorta on sheltered, warm, and humid stands. Owing to the destruction of natural habitats (moorland) L. helle now colonizes almost exclusively anthropogenic ephemeral habitats (abandoned moist meadows) in Central Europe. This results in serious conservation problems, as the biology of the species does not seem to be adapted to a high turn-over rate of habitats. Keywords: butterfly; metapopulation; dispersal; sedentariness; habitat turn-over

Introduction Recent studies on butterfly ecology have contributed considerable additional information in the fields of population structure, dispersal, and conservation (e.g. Thomas and Harrison, 1992; Hanski et al., 1995; Pullin, 1995; Lewis et al., 1997). In particular, metapopulation structures and the types and amount of dispersal seem to be major factors in the long-term survival of populations. As declining patch occupancy and an increasing threat to survival is caused by progressive habitat fragmentation (e.g. Hanski et al. 1994, 1995; Hill et al., 1996), the persistence of a species often relies on networks of suitable habitats, sufficiently close to allow dispersal between them (Thomas et al., 1992; Dennis and Eales, 1997). However, knowledge about the role of habitat corridors in facilitating dispersal and hence maintaining viable populations as well as the knowledge about the distances allowing colonization of empty habitat patches is still fairly poor. Both aspects are of importance to species survival in fragmented landscapes as is the case in Central Europe (e.g. Settele et al., 1996). In contrast to previous studies we chose a butterfly * To whom correspondence should be addressed.

1366–638X © 1999 Kluwer Academic Publishers

species, the Violet Copper, Lycaena helle Denis and Schiffermuller, ¨ 1775, which in Central Europe has probably already been living in more or less fragmented habitat islands for several thousands of years. Being a postglacial relict, the species has always been restricted to a few localities only (Bernardi and De Lesse, 1951; Meyer, 1982 a,b). The strong spatial restriction led to the assumption that dispersal ability might be decidedly poor. The hygrophilous butterfly colonizes moorland and, if lacking such natural habitats, prefers abandoned moist meadows (Réal, 1962 b; Meineke, 1982). An important reason for the decline of this species seems to be the loss of habitats due to the deterioration of wetlands (e.g. Hasselbach, 1985; Meyer, 1980). Nowadays, L. helle is one of the rarest butterfly species in Central Europe and is mentioned in the ‘Red Data Lists’ of Germany (Pretscher, 1984; ‘endangered’) and Europe (Munguira et al., 1993; ‘vulnerable’). Unfortunately, precise information on the butterfly’s ecology which would be crucial for conservation management is still lacking. Taking into account the above mentioned deficiencies and the specific situation in Central Europe, we focus on the following questions essential

K. Fischer et al.

fly species, three with sufficient population size and different habitat configurations were chosen for detailed studies in 1995 using mark-release-recapture techniques (Fig. 2). The patchy habitat distribution within these study sites was suitable for studying the exchange of individuals between sub-populations under various conditions: fallow wetland with some intervening spruce forests (site B), light bog-woodland with clearings (site L), and afforestated wetland, where L. helle is present in fens and along some ditches (site H). The populations were sampled on every favourable day between 1st May and 10th July 1995 (except at site H with a lower number of sampling days). When captured for the first time the butterflies were individually marked (permanent-ink, felt-tip pen) and released at the point of capture, after keeping them for a short time in a cool-box to avoid a ‘mark-release trauma’ (cf. Watt et al., 1977). For each capture study site, the location within a grid system (each cell 20 3 20 m), date, number of mark, sex, distance to the nearest shrubs/trees, percentage of ground covered by P. bistorta, behaviour, and – if required – nectar source plants were recorded. Mobility was estimated by the straight distances between the places of capture and (next) recapture. This, of course, does not reflect the real flight pattern of the butterflies but it roughly indicates dispersal ability and site fidelity. Those estimations as well as the following one can only give minimum values. The individual home ranges were estimated by the minimum area method (Southwood, 1976), using data gathered

for the conservation of this organism: 1. Is L. helle in fact a sedentary species and over what distance can colonization occur regularly? 2. Do barriers and corridors influence dispersal? 3. What essential resources comprise a habitat for L. helle? 4. What appropriate land use could maintain these habitats?

Study sites and methods The study was carried out in the Westerwald area (Rhineland-Palatinate, Western Germany) at elevations from 500 to 600 meters (Fig. 1). The climate is sub-oceanic, moderately cold, and humid (precipitation . 1000 mm/year, average temperature/year 1 6 °C; Sabel and Fischer, 1992). In May and June 1994 populations of L. helle in the Westerwald area were systematically mapped. Therefore, we searched for adult butterflies in all suitable habitat patches in an area of about 250 km2, covering the whole (known) distribution of the species in the Westerwald area. As the males prefer sheltered locations in the vicinity of the larval hostplant (Polygonum bistorta), they are usually easy to find (cf. Thomas and Harrison, 1992). Each patch was visited at least twice during favourable weather conditions. In no case did the second search reveal L. helle where they had not been found on the first search. For each occupied patch, we determined patch area (range 0.2–20 ha), distance to the nearest populated patch (between patch edges; range 200–2100 m), vegetation type and current land use. Out of 83 sites supporting populations of this butter-

Figure 1. Germany.

Location of the survey area and the three study sites for mark-recapture studies in the north-eastern Rhineland-Palatinate region,

44

T h e C o p p e r B u t t e r f l y L y c a e n a h e l l e i n We s t e r n G e r m a ny

from individuals observed at least four times. For description of habitats, 15 plant sociological inventories were carried out according to the method of BraunBlanquet regarding the plant species and their abundance (cf. Muhlenberg, ¨ 1989). The phytocoenosis obtained from the plant sociological inventories was analysed using ‘indicator values’ of vascular plants for ecological parameters (Ellenberg et al., 1992).

Mobility and isolation of habitat patches The majority of individuals were recaptured in the near vicinity of previous captures. 63.5% of the linear distances were less than 40 meters, 89.0% less than 100 meters. Males were found to be significantly more stationary than females (average 37.2 6 60.7 m compared to 60.8 6 67.0 m; Mann & Whitney U-test, p , 0.0001, U 5 38163.5, n1 5 682, n2 5 165). Spearman’s rank correlation indicated a significant, but weak relationship between the distance covered and the time periods between capture and recapture (r 5 0.17; p , 0.0001, n 5 824), thus ruling out serious method-related errors. The flight distances recorded for males were significantly different between the three study sites (Kruskal-Wallis-test, p , 0.0001, H 5 24.2, df 5 2, n 5 682), whereas for females these site differences were not significant (Kruskal-Wallis-test, p 5 0.073, H 5 5.2, df 5 2, n 5 165; tab. 2). If, in the case of multiple recaptures, the respective distances covered by each individual are totalled, the average distances increase to 67.5 6 86.1 m (males) and 97.6 6 107.6 m (females)

Results Capture results In total, 1596 individuals of L. helle were marked during the mark-recapture studies, resulting in 866 recaptures (total observations 2462). The overall recapture rate (in % of marked individuals) was 30.0%, showing considerable differences between the three study sites (Table 1). The average residence time was 7.7 6 6.8 days (median: 6, n 5 471). This did not vary according to sex (males 7.7; females 7.8). The maximum residence times were 34 days for males and 33 days for females.

Figure 2. Map of the distribution of Lycaena helle in the Westerwald area in 1994. A survey identified 83 populations (black points). For extended habitat patches the points give only the patch centres. The triangles mark the position of extinct populations, the letters L, B and H refer to the three study sites for detailed population studies in 1995. Unoccupied patches have not been recorded. The plot is heavily generalized to avoid the exact localisation and exploitation of populations of the protected species. 45

K. Fischer et al.

Table 1. Number of captures, recaptures, and recapture rates of Lycaena helle in the three study sites.

Site B Site L Site H Total

Captures

Recaptures

Males

Females Total

Males

Females Indet.

Total

Males

Females Total

485 106 468 1059

192 75 270 537

343 236 116 695

57 90 18 165

402 329 135 866

42.5 71.1 19.4 35.1

25.0 57.3 5.9 19.9

677 181 738 1596

(significant difference: Mann & Whitney U-test, p 5 0.027, U 5 15819, n1 5 358, n2 5 103). Most individual home ranges were small and varied between 0 (all observations in the same 20 3 20 m2

Site B Site L Site H Total

Females

[

median

[

median

Maximum

38.4 24.3 61.0 37.2

20.0 20.0 20.0 20.0

48.8 62.8 91.5 60.8

30.0 40.0 100.0 40.0

380 280 560 560

2 3 1 6

37.5 65.8 14.4 30.0

grid) and 6960 m2 for males (average: 1075 6 1576 m2, median: 448 m2, n 5 43) and between 408 and 15528 m2 for females (average: 4627 6 4194 m2; median: 2880 m2, n 5 15). The sex-related difference is highly significant (Mann & Whitney U-test, p 5 0.0004, U 5 72.5). No exchange of individuals was recorded between the study sites (distances 5.5 to 8.0 km). But there had been flights between more or less separated parts of the study sites L and B. Twenty-eight flights across a sparse bog-woodland were observed in site L. In three cases, woodland barriers of at least 60 meters in width had to be transversed (Fig. 3). Frequent exchanges were recorded between two parts of this study site, which were separated by a very sparse woodland belt of 30 meters in width. Thirteen out of 21 habitat changing individuals (seven changed twice) were females. Only 16

Table 2. Average ([) and median of movements in meters of Lycaena helle in the three study sites according to markrecapture experiments. Males

Recapture rate (%)

Figure 3. Exchange of individuals between sub-sites of site L. Frequent exchanges occurred between habitats, which were separated by very sparse woodland belts, crossings of wider woodland barriers were rare. The internal straight boundaries indicate the limits of the study site. 46


161.5, n1 5 83, n2 5 12). The habitat patch sizes of the 83 recorded populations were roughly estimated leading to an average size of 1.98 6 2.9 ha (median 5 1 ha). Thirty-four (41.0%) patches were smaller than 1 ha, with the smallest occupied patch being only 0.2 ha in extent (1–2 ha: 33 patches; 3–10 ha: 13; . 10 ha: 3). The size of the largest patch was about 20 ha.

exchanges between sub-sites were recorded for site B. Here, suitable habitats were separated by woodland barriers as well as distance (120 and 280 m; cf. fig. 4). The habitats were connected by a path through the spruce forests. Two direct observations showed that this path is used by butterflies to fly from one habitat to the other. Two other butterflies were caught by a gust of wind and crossed the forest this way. Twelve out of 16 habitat changing individuals in site B were males. Numerous direct observations proved that L. helle moves by using linear structures such as forest edges. In contrast, the species was never seen flying over open fields. Based on the survey in 1994, isolation by distance between occupied habitat patches was analysed. The average distance between occupied habitats next to each other was 598 6 405 m (median 5 400 m, n 5 83). Forty-five (54.2%) patches were not more than 500 m, 73 (88.0%) not further than 1000 m away from the next population. Twelve formerly known populations (own unpubl. data) were found to be extinct. The average distance of those to the next still existing population (1533 6 1087 m; median 1250) was significantly higher compared to the distances between occupied patches (Mann & Whitney U-test, p 5 0.0002, U 5

Behavioural aspects According to the behaviour at the moment of encounter, males ‘flew’ more frequently than females (51.1% to 37.8%) and ‘fed’ (25.3% to 33.3%) and ‘rested’ (23.6% to 28.9%) less frequently. These sex-specific differences in behavioural patterns are highly significant (chi-squaretest, p , 0.0001, x2 5 35.2, df 5 2, n 5 2450). High numbers of observations (up to 130) in some grids were due to concentrations of males, taking up perches close to each other. From these perches, they rapidly started to chase any larger flying insect (such as bumble-bees, dragonflies, butterflies) that approached. In case of non-conspecific intruders the males immediately returned to their perches. Conspecifics were pursued (usually in a typical co-rotating circle flight) until they alighted or flew away. Afterwards, one butterfly

Figure 4. Exchange of individuals between sub-sites of site B. Habitats are separated not only by woodland barriers, but also by distance. The internal straight boundaries indicate the limits of the study site. 47

K. Fischer et al.

and P. bistorta were most frequently visited (65.8% of feeding records). Other important nectare source plants were Cardamine amara, Ranunculus repens and R. acris.

returned to the perch. Frequently males were captured several times at exactly the same perch (up to ten times). Males were never seen exhibiting patrolling behaviour.

Discussion Habitat characteristics

Our data on mobility as well as the long resident times strongly suggest that L. helle can be an extremely sedentary species. The maximum residence time of 34 days is one of the highest ever found in field studies for nonwintering butterflies in Europe. For British butterflies, the longest residence time, given by Shreeve (1992), is 28 days (Maniola jurtina). The average residence times of L. helle are also relatively long compared to field data on other European Lycaenid species (cf. Kockelke et al. 1994; Pauler et al. 1995; Väisänen et al. 1994). The recorded recapture rates can be regarded as typical for sedentary species (cf. Pauler et al., 1995; Scott and Opler, 1975). The considerable differences between the study sites (14.4 to 65.8%) confirm that recapture rates are not only due to species-specific differences, but also to the configuration of the study sites, size and seclusion of populations, as well as study intensity. The behaviour patterns of males and females differ distinctly, which can be related to the mating system (e.g. Rutowski, 1991). The mate-location behaviour of L. helle is obviously aggressive perching (c.f. Cordero and Soberon, ´ 1990). The higher flight activity of males is due to the resulting inspection flights, characteristic for many Lycaenid species (e.g. Scott, 1974; Scott and Opler, 1975; Schurian and Fiedler, 1996). That females were more frequently observed ‘resting’ in the vegetation, does not contradict their higher mobility. Due to the territorial behaviour of males, they usually return to their perches after flights resulting in site fidelity (e.g. Schurian and Fiedler, 1996; Pullin, 1997). Females, however, disperse for longer (but still short) distances in search for oviposition sites (cf. Elligsen et al., 1997; Shreeve, 1992). Additionally, this active search does explain the stronger association of females with P. bistorta, the larval hostplant. Activity data differ considerably between the three study sites (highly significant for males), which is most likely related to the habitat configuration (influence of barriers and corridors). Linear corridors are probably used by L. helle to travel considerable distances between adjacent habitats, as is likely for ditches in site H and paths in site B. The fact that the more sedentary males changed habitats more often in site B is probably due to passive wind-assisted drift, whereas for the wind sheltered site L, active movements can be

In the study area moist meadows with abundant knotgrass (P. bistorta) were clearly preferred. The colonized meadows in particular belong to the Deschampsia cespitosa-Polygonum bistorta-association, often including plant species indicative of nutrient-poor grassland (e.g. Potentilla erecta, Hypericum maculatum) and of fenland (e.g. Carex fusca, Comarum palustre, Eriophorum angustifolium, Viola palustre). This plant community must be regarded as a fallow stage of unimproved moist grassland (Sabel and Fischer, 1992). Indicator values for ecological parameters (Ellenberg et al., 1992) characterize the habitats of L. helle as humid, moderately acidic, and fairly nutrient-poor (average indicator values of the 15 plant sociological inventories: humidity 7.1, soil reaction 4.9, nutrient ratio 4.5). Those findings are supported by the results obtained from the survey of L. helle populations in the Westerwald area. The Deschampsia cespitosa-Polygonum bistorta-association occurred at 78 out of 83 (94.0%) sites supporting populations, and at 43 (51.8%) sites it was the only colonized plant community within the habitat patch. Only in five habitats, which consisted of low and transitional moor, this specific association was not found at all. In the other cases a mixture of plant communities including the Deschampsia cespitosa-Polygonum bistorta-association, fenland (Caricetum fuscae, 20 sites), meadow-sweet fallow land (Filipendulion ulmariae, 14 sites) and oligotrophic grassland (Polygalo-Nardetum, 3) was found. As already indicated by the above mentioned plant communities, most of the habitats (79 out of 83; 95.2 %) underlie no current land use. Only four populations persisted under extensive (2) or sporadic (2) grazing regimes. Within the moist meadows the butterflies were restricted to the vicinity of woodland and shrubs. For all observations the average distance to the nearest shrubs/trees was only 3.6 6 2.7 meters (median: 3.0 m, n 5 2461). The occurrence of P. bistorta in the habitats is essential, for egg-laying as well as feeding of larvae in Central Europe is restricted to this plant species (e.g. Weidemann, 1995). Females significantly prefer denser ground coverage of this plant than males (25.4 6 16.2 to 21.5 6 13.1%; Mann & Whitney U-test, p , 0.0001, U 5 540493.5, n1 5 702, n2 5 1753). Adults fed on flowers of 17 different plant species. Cardamine pratensis 48


methods tend to underestimate the real dispersal ability due to methodological constraints (cf. Dennis and Bardell, 1996; Dennis and Shreeve, 1997; Settele et al., 1996). Nevertheless, studies using large scale surveys show that at least for small sedentary species and under normal conditions (for the possible impact of extreme weather events see Dennis and Bardell, 1996) distances of 1 km or more between suitable habitats can act as major barriers to dispersal and lead to a failure of colonization (Thomas and Harrison, 1992; Lewis et al., 1997), whereas for other species with strongly developed dispersal behaviour barriers seem to be non existent (Brunzel and Reich, 1996; Brunzel, 1996). Some further evidence was found to support this idea. The existing spatially restricted colonies in Central Europe are still concentrated close to the edges of the last glaciation (Meyer, 1982a). Additionally, numerous described local forms (even though they are not valid as subspecies in a taxonomic sense) indicate a very low level of long-distance dispersal and exchange (cf. Bernardi and De Lesse, 1951; Meyer, 1982 a,b). Under natural conditions the butterfly is strictly linked to ecosystems which are relatively constant over long periods of time, especially bogs and swamps (cf. Réal, 1962 a-d). To survive there, efficient colonization strategies are not needed. Moreover, such moorland biotopes have always been rare and often isolated in the mountain regions of Central Europe, thus resulting in a low probability of reaching a suitable and free habitat. There should therefore be a strong selection against dispersal. Thus, L. helle seems to be in need of continuity of habitats in space and time.

assumed. Owing to frequent inspection flights (up to 100 in two hours; Scott, 1974), males should be more frequently affected by gusts than females. But in general, the arrangement and the structure of barriers between occupied habitats seems to be most important for the connectivity of adjacent populations. As the level of activity of L. helle is highly correlated with the solar radiation (Meyer and Helminger, 1994; Réal, 1962a), it is extremely unlikely that individuals will cross dense spruce forests. On the other hand open fields probably act as barriers due to the restriction to wind-sheltered stands, at least for active dispersal. Thus, L. helle seems to be characterized by a rather poor individual ability to move between neighbouring habitats, if barriers are present. Furthermore, our data (infrequent dispersal between adjacent populations, cf. fig. 4) as well as the occurrence in distinct habitat patches suggest that L. helle possibly exists in a metapopulation structure, which seems to be a major factor in the persistence of many butterfly populations (e.g. Brunzel and Reich, 1996; Hanski et al., 1994; Hanski et al., 1995; Thomas and Harrison, 1992; Lewis et al., 1997). Therefore, the basic question is at what scale (and distances) colonization of vacant habitats does occur. Regarding habitat requirements L. helle, like other butterfly species, is restricted to sheltered locations in the vicinity of shrubs or trees (c.f. Dover et al., 1997; Elligsen et al., 1997). The dependence on sheltered stands is apparently so strong, that more open habitats cannot be colonized, even if all other requirements are met (Réal, 1962d). Together with published data (Hannemann, 1928; Réal, 1962 a-d; Weidemann, 1995), nectar feeding of adults is confirmed for 33 plant species to date. Thus, L. helle can be regarded as fairly opportunistic concerning the use of nectar source plants. According to our observations and the bibliographical references, the basic habitat requirements of L. helle in Central Europe can be described as follows: (1) moist meadows with abundant P. bistorta (larval hostplant), in particular the Deschampsia cespitosa-Polygonum bistorta-association, (2) sheltered, warm and humid stands in the vicinity of shrubs, forest edges etc., (3) nectar source plants. Neither these findings nor the existence even in fairly small habitat patches explain the rarity of the species in Central Europe (e.g. Meyer, 1980), for these requirements should be met in many European landscapes. Indeed, the butterfly does not occur at all places, where it could be expected (SBN, 1987). We conclude that its sedentary behaviour and a resulting low dispersal ability might be the decisive factor. Of course, one has to take into consideration that mark-recapture

Implications for conservation As a consequence of the destruction and deterioration of nearly all natural moorland in Central Europe, L. helle currently colonizes almost exclusively anthropogenic habitats, particularly abandoned moist meadows. This results in serious problems for the conservation of this species, as these habitats are ephemeral over time and the biology of L. helle does not seem to be adapted to a high turn-over rate of habitats. Clearly, this butterfly is able to colonize (neighbouring) habitat patches close enough to be reached, as shown by our markrecapture experiments and the occurrence in secondary habitats. However, colonization seems only to happen at a strongly restricted spatial scale. Thus, besides the existence of suitable habitat patches (cf. Dennis and Eales, 1997), the distances allowing colonization of empty habitat patches seem to be most important. The 49

K. Fischer et al.

Acknowledgements

maximum single step colonization distances of butterflies is species-specific (Thomas et al., 1992). For L. helle a frequent and successful colonization within a few years seems probable only for distances of a few hundred meters. Our data on the occurrence of L. helle in the Westerwald area show that most of the existing populations were not more than 500 m distant from the next occupied habitat patch. Furthermore, isolated populations generally seem to have a higher extinction risk than connected ones (cf. Hanski et al., 1995; Hill et al., 1996). Thus, L. helle is likely to be extremely susceptible to habitat change in isolated habitat patches. This might have led to the extinction of the butterfly in most of the formerly occupied locations (cf. Hasselbach, 1985; Meyer, 1980). Conservation measures for this species must not only take into account how to manage the habitats to support large populations, but the spatial arrangement and connectivity of suitable habitats as well (cf. Thomas et al., 1992). Because of the instability of the secondary habitats, some kind of management is unavoidable. Otherwise P. bistorta as well as other substantial habitat elements will vanish in the course of succession. The regeneration and re-establishment of moorland will take long periods of time and is impossible in most of the regions where L. helle currently occurs in Central Europe. There is obviously no alternative (apart from introductions) to the protection of the existing colonies within their secondary habitats, at least none, which would meet the requirements of this species in time. Because most colonies exist on recently abandoned moist meadows (e.g. Meineke, 1982), mowing seems to be most appropriate. Taking into account the sudden habitat deterioration caused by every cut, rotational mowing of single habitat patches in autumn in cycles of several years might be most favourable. The mowing should follow the pupation and leave out areas with shrubs as an essential habitat requirement. However, such a mowing system is highly artificial, expensive and far away from the economic requirements of the local farmers. In general, the protection of specific land use patterns in cultural landscapes by management measures without real economic returns is a doubtful conservation strategy (Plachter, 1995, 1996). Grazing might be a better alternative. Indeed, in the course of mapping, four colonies of L. helle were found in rough cattle pastures, making such attempts promising. This would presumably require pasturing on a fairly large spatial scale with irregularly grazed patches. Such a largescale pasturing by herdsmen supports other butterfly species, too (cf. Elligsen et al., 1997).

The authors wish to thank the Ministry of Environment and Forestry of the State of Rhineland-Palatinate for supporting the study by grants from the scholarship ‘Arten- und Biotopschutz Rheinland-Pfalz’, the Koblenz and Siegen-Wittgenstein district governments for granting permission to pursue this study, Konrad Fiedler (University of Bayreuth) and two unknown referees for critical and helpful comments on the manuscript, Angelika Fischer-Munsch (Westerburg), Peter Zofel ¨ (University of Marburg), and Jason Audsley (Marburg) for assistance in data analysis and the linguistic improvement of the manuscript, respectively. Peter Fasel, Biological Station Rothaargebirge, and Ernst Brockmann, Lepidopterological Study Group of Hesse, contributed unpublished local data on the butterfly.

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