장음표시 사용
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EDGE EFFECT ON WEEVIL AND SPIDER COMMUNITIES AT THE BURR Np IN HUNGARY 28 l
habitats was significantly higher than in the forest interior. It may expla in the hi glispecies richness we observed at the forest edge and the mea low. For ex ample Phyllobius vemertinus FABRICIUS. lJ92) occurred exclusive ly in the me adowand iis siod- planis Achilleia, Dactylix and Fragaria species) can be also mund in large number in the me adow. In the forest elige the most frequent occurrence of Otior Gynchus fullo SCHRANK. lJ8 l) can be explained with the abundant pres- ence of iis 1 ood- planis se. g. Pruri HS minoSa, Criataequ5 Sp.). As the smod-planis Achillea sp.) of Euxomus ovulum GERMAR. l824 were frequent both in the meaclowand in the forest elige, this weevit species was also captured in both habitats. Withthe decreas ing of the canopy cover heims typical of meadow can also penetrate into the forest edge and thus species composition of the herbaceolis layer of the forest elige and the mea low hecome more similar MESZAROS i 988). Similari ty of the species composition of herbaceolis planis can explain both the higher similari ty of weevit communities of the forest edge and the me adow Fig. Pa) and the statis ti- catly not significant difference in species richness Fig. l a). Howe Ver, many polyphagous weeviis l8.6 π of the sampled species and 4J.2R of the species captured in the forest edge) occurred exclusi vely in the forestedge Appendix l). This faci cannot be explained by the presence of the smod- planis but rather with the special ab iotic microclimate) and biotic en viron mental factors e. g. competition, predation) that characteri se the forest edge. Namely, proximi tyof two structural ly dissimilar habitat s meaclow and forest) resulis in specialabiotic en Viron mental conditions se. g. air moisture, uir temperature, light condi ii Ons, etc.) at the forest elige, whicli can also influence both the abundance, micros ite prefere iace, distribution of species and the species interacti Ons, such as predation competition, etc. MURCI A l 995). ge ejeci ori mide ra
stu lying spider communities of a forest and the adjacent gras S, also reported that species richness was the highest in the forest elige. Our resulis also corroborate that there is a significant elige effect on the spider assemblages, that is the species richness is significantly higher in the forest edge than in the adjacent habitats Fig. l h). Many pre Vious works demonstrated that structural diversi ty of habitat s andiis derived changes in the ab iotic elavit onmental conditions are likely to be sonae of the most important factors structuring spider communities MAEI FAIT et a L l 990.
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l98 l). In the studied forest eclge the leas litter, the herbs and the shrubs contribute to the structural diversi ty and heterogenei ty of the habitat. Moreo ver, habitat heterogenei ty suppota the development of microhabitats, which also promote higherspicier species richness. Increas ing cover of the leas litter, the herbs and the shrubs may Support the pre Selace of dec OmpOSei S, phytophago us and predatory invertebrates avai lable prey for spiders, which also increase spider species richness
At the studi ed spatiat scale dispersal bet ween adjacent habitats may also influence species richness. HEUBLEIN sl 982) reported that by unfavoti rabie en viron mental conditions microclimate, sinod conditions, etc.) spiders migrate in habitat
with favoti rabie conditions. Furthei more, Ontogeny of SO me Spider Specie S may
undergo in different habitats. HEUBLEIN l 982) po inted out that juveniles of Pisauria mirabilis CLERCK. lJ5J) are abundant in the open habitats, while adulis in the forest edge and in the forest. This faci can explain the dominance of Pisauriam irrabilis CLERCK. lJβJ) both in the meadow and in the forest in otir research Appendix 2). VI IJ V and KOSSI ER GESCHIESE l 96J) reponed that males of sonae spider species moved in the periph ery of the habitat following copulation, in orderio avo id cannibalis in and intraspecific competition. The mentioned dispersal processes may also contribute the observed hi gli species richness in the forest edgeand perhaps the similari ty of the spider communities of the forest and the forestedge Fig. 2b) is due to these move ments. DO NI E et a l 996) also reported that spicler composition os forest edge was more similar to the forest interior than to the
TOTI ME RESZ l99J. l 998) and revealed that there are significant edge effecis onthe studi ed phytophago us and predator invertebrate groups. Our resulis pro Ved that forest edge have the fame effect on the species richness of both of the studi ed invertebrate gi Oups. It Stresses that forest edges may have a cruciat role in the maintaining of biodiversi ty theres ore their conservation is essentiat. The hi gli species richness observed in the forest edge is due to the presen ce Ofspecies characteristic of each of the adjacent habitats meadow and forest interior)plus edge- associaled species. Forest elige with specific abiotic and biotic en viro n-mental Conditions may insure sui table fee ling, hibernation and reproduction habitat for species HEUBLEIN l 982. MURCI A l99 β). It is recordabie, that forest edges
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have vi able invertebrates frona the adjacent habitaes. This indicates that forest ed gesare supposed to he 'source'' habitats PULLIAM l 988) for smali scale movemenis contributing to reco very of species in the adjacent habitais destroyed for ex amplethrough tillage, bum in g, logging and creating plantation 'sin kV habitais, sensu
PULLIAM l 988). Theremi e forest edges en coui age the regenerntion Ind recOVeryos assemblages of adjacent disturbed habitats. This character of forest edges is also applied for nature management practices. For ex ample in forests with poorly de-veloped edges se. g. plantation or managed forest) management schemes attempt tocreate a diverse edge vegetation by sowing or planting herbs and shrubs and by cut-ting marginal forest treesto reduce sh ad ing KOGEL et al. l 993. KRUSIGal. l 996). MoreOVer, Other management practices widen and shape the existing edge of for
Howe ver only a detai led study, based on ecological knowledge and analysing more trophic levets, would be able to determine the generat man age mentgui delines for conservation and ma inten ance of biological diversi ty.
ἐAchnowledgements - The authors are thanksul to Pro f. Dr. ZOLTAN VARGA sor propos ing theresearch problem and sor his valvabie suggestions. we are gratesul to Dr. CSABA SZINETAR for help-ing in the identification os the problematic spider species. Special thanks is to be gi ven to Dr. LASZLOS ZABo for his invaluabie directions during sampling and identification period. The research was supported by the Pro Regione Fund and the Pro Renovanda Cultura Hungariae Fund.
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Revi sed version received i Pth March. 2000. accepted 20th December. 2000. publislied i th May 200l
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Λppendix l. weevit species and individuals captured in the studi ed habitais Species Forest interior Forest edile Mea lowCURCULIONIDAE Otiorrhynchinae Omia nimia mollina
Brachyderinae Briachymnius villosulus
Cleoninael irinus Iurhintili S
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Curculioninae Curculio elePhaS
Eri rhininae Notiaris maer eli
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TETRAGNATHIDAE Metellina meriget
PISAURIDAE Pisauria mirrabilis
DICTYNIDAE Dictyna arundinaCea
CLUBIONIDAE Cheimccinthium SP.