Warming Climate P mugo and Future of Sudeten Erebia

The long-term persistence of these two Sudeten species of Erebia butterflies will depend on the continuous presence of suitable open habitats in the upper parts of the mountains. The current distribution patterns suggest that the habitats do not necessarily need to be located above the climatic timberline. Also, none of the species is threatened by direct destruction of habitats, as most of their sites already enjoy legal protection, either in the form of reserves within the Jesenik-protected landscape area, or as a core zone of the Krkonose/Karkonosze national parks. The populations are abundant and/or interconnected, further adding to the rather optimistic prospects.

As revealed by pollen and macrofossil records, trees and shrubs ascended to higher elevations, possibly by as much as 100 m, at the height of the Atlanticum period (Jankovska 2004; Treml et al. 2008). This likely diminished the extent of subalpine habitats, relative to the current situation. However, because the specialized alpine biota, including the Erebia butterflies in Jesenik, had survived the period in situ, the summit habitats could not be closed-canopy forest, but rather a patchwork of tree growths and open sites. In the same vein, the current diversity of alpine relics might survive the recent warming episode, provided the warming does not get too extreme and the habitats in the uppermost elevations remain rather open. The processes that control tree growth must be adopted by conservationists in order to support the threatened relic species.

An important aspect concerns the species richness in alpine relics in Krkonose and Jesenik. Despite containing much smaller subalpine area, Jesenik hosts approximately as many relic Lepidoptera as do Krkonose (Table 1). The Krkonose fauna is relatively poor, apparently due to the presence of the species-poor vegetation belt of P. mugo. The dwarf pine used to cover even larger areas than in present before it was cleared by humans to obtain pastures, and there is no doubt that it expanded to still higher altitudes during the climatic optimum. In this period, relic alpine biota likely retracted to rocky slopes and scree, unsuitable for pine growth. Interestingly, the pine is not native to Jesenik, but had been planted there at the turn of the 20th century. Thus, the existence of P. mugo might explain the lack of some relic Lepidoptera associated with grassland formations in the Krkonose Mts., such as both species of Erebia and two Clepsis tortricids. On the other hand, several species absent from Jesenik are associated with the rocky habitats (Elophos operaria,

Table 1 List of all Lepidoptera species associated with high mountain (subalpine and alpine) habitats and recorded from Krkonose (KRK) and Jesenik (JES) Mts., Czech Republic

Species

Family

KRK JES Distribution

Table 1 List of all Lepidoptera species associated with high mountain (subalpine and alpine) habitats and recorded from Krkonose (KRK) and Jesenik (JES) Mts., Czech Republic

Species

Family

Incurvaria vetulella (Zetterstedt, 1839)

Incurvariidae

+

+

A,

B, C

Lampronia rupella (Dennis et Schiffermüller,

Prodoxidae

+

+

A,

B, C

1775)

Argyresthia amiantella (Zeller, 1847)

Yponomeutidae

+

-

A,

C

Rhigognostis senilella (Zetterstedt, 1839)

Plutellidae

+

-

A,

B, C

Denisia nubilosella (Herrich-Schäffer, 1856)

Oecophoridae

+

+

A,

C

Elachista kilmunella Stainton, 1849

Elachistidae

+

+

A,

B, C

Chinodes viduella (Fabricius, 1794)

Gelechiidae

+

+

A,

B

Sparganothis rubicundana (Herrich-Schäffer,

Tortricidae

-

+

B

1856)

Clepsis steineriana (Hübner, 1799)

Tortricidae

-

+

A

Clepsis rogana (Guenee, 1845)

Tortricidae

-

+

A,

B, C

Phiaris obsoletana (Zetterstedt, 1839)

Tortricidae

+

_

A,

B, C

Pseudococcyx mughiana (Zeller, 1839)

Tortricidae

+

_

A,

C

Eudoniapetrophila (Standfuss, 1848)

Crambidae

+

+

A,

C

Eudonia sudetica (Zeller, 1839)

Crambidae

+

+

A,

B, C

Catoptria maculalis (Zetterstedt, 1839)

Crambidae

+

_

A,

B, C

Catoptria petrificella (Hübner, 1796)

Crambidae

-

+

A,

C

Udea alpinalis (Dennis et Schiffermüller, 1775)

Crambidae

+

+

A,

C

Erebia epiphron (Knoch, 1783)

Nymphalidae

_a

+

A,

C

Erebia sudetica Staudinger, 1861

Nymphalidae

-

+

A,

C

Isturgia roraria (Fabricius, 1776)

Geometridae

_

+

A,

C

Elophos operaria (Hübner, 1813)

Geometridae

+

_

A,

C

Psodos quadrifaria (Sulzer, 1776)

Geometridae

+

_

A,

C

Glacies alpinata (Scopoli, 1763)

Geometridae

+

+

A,

C

Perizoma obsoletata (Herrich-Schäffer, 1838)

Geometridae

+

_

A,

C

Eupithecia silenata Assmann, 1848

Geometridae

+

+

A,

C

Apamea maillardi (Geyer, 1834)

Noctuidae

+b

_

A,

B, C

Xestia alpicola (Zetterstedt, 1839)

Noctuidae

+

_

A,

B, C

Diarsia mendica borealis Zetterstedt 1839c

Noctuidae

_

+

B

Total

20

18

Based on Liska (2000), with nomenclature modified after Karsholt and van Nieukerken (2004). "Distribution" describes extra-Sudeten distribution of individual species, in which A = occurrence in the Alps and other mountains of W and C Europe; C = occurrence in the Carpathians and other systems of SE Europe; B = occurrence in Northern Europe "Intentionally introduced population: see text for details bA single record, doubted by some authors cA population with diurnal activity, likely distinct from "lowland" D. mendica. Its exact status needs clarification

Catoptria maculalis), a habitat mostly absent from the Jesenik Mts., but existing in the Krkonose Mts.

Another important aspect concerns the grasslands. Recently, there is much effort to restore the "cultural" grasslands in the Sudeten Mts. by reinstalling the traditional management, and the prospects are optimistic (e.g., Krahulec et al. 1997; Pavlu et al. 2003; Hejcman et al. 2005, 2006). However, the natural subalpine grasslands had also been managed for centuries by grazing and haymaking. Cessation of activities, and a resulting non-intervention regime, causes a gradual impoverishment of the vegetation, prevalence of a few dominant species, and accelerated trees and shrubs expansion (Klimes and Klimesova 1991; Hejcman et al. 2006). Effects on Erebia species are not yet apparent, but may eventually manifest as direct loss of habitats. The non-intervention management is sometimes advocated as return to a "natural state," which is a risky adventurism in the face of losses of sensitive species, and under the threat of warming-accelerated habitat changes.

E. epiphron requires long-term preservation of open grasslands, preferably interconnected to buffer for its poor dispersal ability. (Recall the decreased genetic variation of the isolated lateral Jesenik population). In Jesenik, where only the subalpine grasslands exist, blocking of tree growth, including the removal of non-native dwarf pine P. mugo, represents the only way to support its population. Because Krkonose are higher than Jesenik, the introduced population can be viewed as a genetic reserve, having a higher chance of survival should warming climate eradicate the species in Jesenik. Even here, ascending timberline should be kept in check, and cultural grasslands below the timberline should be managed using approaches mimicking the traditional meadow husbandry.

The situation of E. sudetica is more complex, but essentially similar. The structurally rich, "notched" timberline sites with sparse growths of trees may be ascending, but this will not necessarily threaten the populations unless the sites are artificially afforested by spruce or dwarf pine. Practically, all these timberline sites are fairly stable because they are periodically affected by avalanches, which keep them devoid of trees. The fate of the more ephemeral forest-belt populations seem less optimistic, as the vast clearings, now hosting the highest abundance of the species, will gradually succumb to forest re-growth. To support the forest-belt populations, natural disturbance factors opening up canopy, such as windfalls and landslides, should be welcomed rather than abhorred and battled against, and active steps to open the canopy structure at such sites as woodland spring areas and valleys of mountain brooks should be undertaken.

Any predictions on the future of the two butterflies are thwarted by the lack of understanding of ecophysiological limits of the species. So far, we understand that they need cool conditions for development, and it seems likely that the limits operate on requirements of winter larvae. We do not know, however, whether the required condition is sufficiently long allowing uninterrupted winter freezing for uninterrupted hibernation, or whether sufficient height and duration of isolating snow cover is necessary. In the first case, the larvae would be threatened by osmotic stress if the winter gets warmer, while in the latter, they may die from frosts if the snow covers diminish (cf. Hodkinson 2005). The mechanisms of cold (or heat)

tolerance of both species are tractable by experimentation and the findings will be critical for forecasting the responses of both species to changing climate.

Acknowledgement We thank O. Cizek, T. Kuras and P. Vrba for inspiring discussions. Field studies of Sudeten Erebia were supported by Palacky University Olomouc, and by Jeseniky Landscape Protected Area and Krkonose National Park administrations; particular thanks to conservation officers P. Balaz, V. Kavalcova, and J. Vanek. Molecular study of E. epiphron was supported by Grant Agency of the Czech Republic (B6001306/2003). Monitoring of E. sudetica is supported by the Czech Conservation Authority, Grant Agency of the Czech Academy of Sciences (600070601) and Czech Ministry of Education (LC06073, 6007665801).

Due to their borderline position and the complex 20th century history, Sudeten Mts. have different names in different languages, which introduces much confusion to biogeographic literature. We present below a simple translation guide for the toponyms appearing in the chapter. They are ordered alphabetically, according to valid names in Czech, and provided, if appropriate, with corresponding toponyms in German [D], English [GB], and Polish [PL]. Jesenik (= Hruby Jesenik, Jeseniky) [CZ] = Altvater Gebirge (=Hochgesenke) [D]; Kralicky Sneznik [CZ] = Glatzer (= Grulicher, Spieglitzer, Großer) Schneeberg [D] = Snieznik Klodzki [PL]; Krkonose [CZ] = Riesengebirge [D] = Giant Mts. [GB] = Karkonosze [PL]; Lucni bouda [CZ] = Wiesenbaude [D]; Praded [CZ]=Altvater [D]; Rychlebske Hory [CZ] = Reichensteiner Gebirge [D] = Golden Mts. [GB] = Gory Zlote [PL]; Rychorska bouda [CZ] = Rehornbaude [D]; Snezka [CZ] = Schneekoppe [D] = Sniezka [PL]; Sumava [CZ] = Böhmerwald [D]

Was this article helpful?

0 0

Post a comment