DATA ON ARVICOLID VOLES (MAMMALIA: RODENTIA) FROM VRANCEA (ROMANIA)

Transcription

1 Trav. Mus. Hist. nat. crgrigore Antipaw Vol. XXXIV pp nov DATA ON ARVICOLID VOLES (MAMMALIA: RODENTIA) FROM VRANCEA (ROMANIA) DUMITRU MURARIU Sur 107 excmplaires des rongeurs collect6s dans la r6gion centrale-orientale de Roumanie (Vrancca), deux especes des microtines reprbsentent un pourcentage de 58% (Clethrionomys glareolus et Pitymys subterraneus). Si la premibre espbce est rcpresent6e par des populations stables, avec beaucoup des individus, I'autre est rare pour la faune de Roumanie. Placed in the central-eastern part of Romania, Vrancea county includes the narrow plain of the Siret River and hills..the Siret gets here the Putna River with its tributaries (more important being RBmnicul Sgrat, Leica and Milcov). It is bordered by Vrancea Mountains with their summits: Sboina (1 657 m), Lgc3ut (1 776 m) and Goru (1 782 m). Its surface, of around 5,000 sq km, is mostly covered by deciduous woods or mixt with conifers (186, 600 ha), grazing and hayfields, vineyards and orchards. As regards the surface, the arable areas (150, 200 ha) follow imediately the woody ones. Within such a mosaic of natural and arranged ecosystems numerous small mammal species occur in addition to those large and middle sized. In this paper we will deal only with the voles of Vrancea area. All mammals of Vrancea were the subject of a previous paper (Mu r a r i u, 1976). MATERIAL AND METHOD During the period 8t11-14t11 of July 19E, 107 specimens of small mammals were collected, using different types of traps, from the surroundings of Lepqa - Vrancea locality. Sixty-two of them belong to the voles, represented by 2 species: Clethrionomys glareolus and Pitymus subterranneus. The material was measured, using common methods, identified and preliminarily prepared on field. The specimens kept in alcohol were prepared in laboratory as skins and skulls. They are preserved in the collections of the "Grigore Antipa" Museum of Natural History of Bucharest.

2 370 DUMITRU MURARIU Abreviations Lengths are given in millimetres. L = body length C = tail length T = tarsus length Au = ear auricle length Weight (Gr.) is given on grammes. RESULTS Today, voles are included within the Arvicolidae Family. In the Romanian fauna there are 8 species. In a previous paper (M u r a r i u, op. cit.) only 4 Arvicolidae species were mentioned from the Vrancea County. In the 1992 collecting there are absent Microtus arvalis and ArviCOla terrestris. Clethrionomys glareolus and Pitymys subterraneus (Mu r a r i u, op. cit.) were rediscovered. Clethrionomys glareolus It is the prevailing species among the small mammals collected from the surroundings of Lepqa - Vrancea locality, in From the 58 specimens only one male was juvenile (L = 48; C = 41; T = 18; Au = 14; Gr. = 20). In the first half of July, the individuals born in spring of that year were already adults, capable of breeding. That is the explanation of the presence of the populations with a restored number of individuals, in spite of the winter hardness and the predators activity, from autumn to spring. According to table 1, it can be observed that the individuals of this species from Vrancea have the body sizes and the weight on the average, smaller than of the other populations from Romania (S i m i o n e s c u, 1979). While the body length exceeds 90 mm in all 5 populations studied from the Gut% Mountains, Bistrifa., CeahlHu and Suhard, in that one from Vrancea it is smaller than 90 mm. The same proportion is kept in the tail length. As regards the tarsus length, it is occured a value inversion, only the population from the Gut2i Mountains being comparable with that from Vrancea. The differences which appeared during the measurements of the ear auricle length seemed to be caused by the methods used not by the population characteristics. Taking into consideration M i 11 e r ' s (1908,,1912) mentions, concerning only 5 adult specimens of Cl. glareolus from Hafeg, the medium values are greater: L = 105.4; C = 45.5 and T = 17.8.

3 ARVICOLID VOLES FROM VRANCEA - ROMANIA 371 Comparative body lneasurements of the populations of Clethrionomys glareolus from Vrancea with another five populations from Romania (S i m ion e s c u, 1979) Table 1 Simionescu, 1979 Measurements Vrancea, 1992 Gutai Mountains Bistritei Mountains. Sp. min. med. max. Sp. min. med. max. Sp. min, med. max. Simionescu, 1979 Measurements llargu Mountains Cealillu Mountains Suhard Mountains Sp. min. n~ed. max. Sp. min. med. rnax. Sp. min. md. max. S i m i o n e s c u ' s (op. cit) remarks on greater values in the populations from the areas of a low altitude in comparison with those from the mountain areas cannot be supported wlien both compared population are from mountain areas. We rather think that it is about size differences according to the number of Cl. glareol~ls individuals from the first generation (April-May). Their weight and size decrease gradually up to the breeding period. K a i k u s a 1 o (1972) considers that the individuals born towards Septen~ber have a lower growth rhythm and reach the sexual maturity after winter time. In the same time, individuals born in spring reach the sexual maturity and breed in the summer of the same year. Within this last category we place the population of Cl. glareolus from Vrancea. The collectings were made in July. because of this, their size and weight is smaller than of the other population of the same species from Romania. According to our results, in Romanian Plain Cl. glareolus is absent in the deciduous woods and in the field areas. The species is characteristic for all the deciduous woods or of conifers or mixt (G r o m o v and P o 1 y a k o v, 1992). S i m i o n e s c u (op. cit.) found it in the Bsrnova Forest (Moldavia) at an altitude of only m. The populations of a low altitude from Poland (S e r a fin s k i, 1968), as well as those from Moldavia are continuously occurred in compact woods, perhaps being favoured by the latitude difference in coniparison, for example, with the Romanian Plain. Mi 11 e r (1912) himself collected Cl. glareolus from

4 372 DUMITRU MURARIU southern Romania only after 480 m altitude (Buqtenari - Prahova), east of C2mpina (in the present Telega commune). Pitymys subterraneus Another vole species, collected by us from Vrancea is Pitymys subterraneus. Because of the small number of the collected specimens, all males, we haven't the opportunity to establish a real medium value, from the statistical point of view. Thus, further on we present all the measures in absolute figures: L= C= T= Au = Gr. = In our previous collectings (Mu r a r i u & coll., 1979), P. subterraneus appeared sporadically, in a small number of specimens. But, taking into account that the collecting of 3 specimens in only 4 nights, made from the surroundings of Lepqa - Vrancea, it means that a steady population still exist there. In hilly and plain areas we collected only one or two specimens. Being depedent on the forests presence, its present distribution seems to be discontinuous, with isolated populations, in Romania. But, unlike Cl. glareolus, P. subterraneus is still present in southern Romania (M u r a r i u & coll., op. cit): The small number of individuals is, first of all, due to the diminishing of the afforested surfaces in hilly and plain areas. Unfortunatelly, these are exploited and grazed, the necessary ecological conditions being preserved only in small limited areas. On the other hand, the prolificacy of this species is lower than in the other voles species. K r a t o c h v i 1 (1970) remaks that the P. subterraneus males doesn't reach the sexual maturity in a proportion of 25%. The others, 75%, winter in subadult state. That is why P. subterraneus has maximum two generations a year. Being already adult, the males born during the spring time participate to the second generation, too. K r a t o c h v i 1 (op. cit.) made some correlations between the seasonal development, the size rise and fall according to the breeding period and the longevity of the individuals belonging to different generations. The same remarks made on Cl. glareolus, for July, can be done on P. subterraneus from Vrancea (1992), too. At least one of the three collected individuals belonged to the first generation of that year. H a m a r & coll. (1974) presents a map of Romania in which the places are marked (without citing the localities within the text or noting them on the map). As we have mentioned above, the map proves the large distribution of P. subterraneus in Romania but with a white spot just in the central-eastem area of the country. The aim of his paper is, on the one hand, to find the resemblings of the plain populations of Romania with those from Bulgaria. On the other hand, P. subterraneus populations of high altitude from Romania are compared with the Central-European ones.

5 ARVICOLID VOLES FROM VRANCEA - ROMANIA 373 CONCLUSIONS 1. Voles, considered today as a subfamily of the Arvicolidae, are represented by eight species in Romania: Clethrionomys glareolus, Arvicola terrestris, Ondatra zibethicus, Pitymys subterraneus and four species of the Microtus genus. From them, only two were collected in July, 1992, from the surroudings of the Lepva - Vrancea locality (Cl. glareolus and P. subterraneus). The others occur in the Carpathian curved area of the central-eastem side of Romania but at altitudes and different ecological conditions. They are absent in our collectings. 2. From 107 collected specimens of small rodents, C1. glareolus represents 58%. Although all of them were considered adult specimens, their body sizes have lower medium values then those remarked in the other populations from Romania. Making a correlation between our data with those from the literature it resulted that most of the individuals were from the first generation of This is the explanation of their smaller body size and weight values. 3. P. subterraneus has a large distribution according to the altitude, in comparison with the previous species. However, the diminishing of the compact wood surfaces from the plain and hilly areas, as well as its weak prolificacy led this species to the group of threatened animals of Romania. 4. The continuous changings of the natural ecosystems due to the greater influence of the anthropic factor represent a cause of the populations decreasing of the voles of Romania. In Vrancea county there aren't polluting industrial plants, but the soil slidings, the radioactivity increasing and climatic changings damage the food and the micro-environment of voles - less competitive than the other rodents and an easier prey. As an example we can mention the refuge to higher altitudes of the snow vole and thc alarming decreasing of the populations of the red bank vole. DATE ASUPRA MICROTINELOR ARVICOLIDE (MAMMALIA: RODENTIA) DIN VRANCEA ( R O ~ A ) REZUMAT Colectitrile de mamifere mici din vecingtatea localitgtii Lepqa - Vrancea au permis ca tntre alte specii de rozgtoare sl fie identificate $i doug microtine (Clethrionomys glareolus $i Pitymys subterraneus). Prima specie este in procent de 58%, majoritatea indivizilor adulti provenind din prima generatie a anului de colectare (1992). Mitsurgtorile lor corporale $i greutatea sunt inferioare celor consemnate in literaturr pentru alte populatii din Romlnia. P. subterraneus a rgmas in populatii mici $i izolate, "i pitdurile de clmpie, deal $i munte. Prolificitatea redus2 $i deteriorarea ecosiste~nelor naturale de pgdure au determinat statutul de raritate pentru aceastg specie.

6 374 DUMITRU MURARIU REFERENCES GROMOV (I.M.), POLYAKOV (I.YA.), Voles (Microtine). In: Fauna of the U.S.S.R. Mammals (Washington, D.C.), 3,8: 1-XXV, HAMAR (M.), SIMIONESCU (VIORICA), SUTOVA (MAIA), GHIZELEA (GABRIELA), New data on the systematics and distribution of the genus Pitymys McMurtie, 1936, in Romania. Proc. of. Int. Symp. on Species and Zoogeography of European Mammals. Brno: KAIKUSALO (A.), Population turnover and wintering of the bank vole. Clethryonomys glareolus (Schreb.), in southern and central Finland. Ann Fenici. 9: KRATOCHVIL (J.), Der Geschlechtzyklus der Mannchen von Pitymys subterraneus und Pitymys tatricus (Rodentia) in der Hohen Tatra Listy, 19,l: MILLER (G.), The recent Voles of the Microtus nivalis Group. Am. and Mag. of Nat. Hist.. 1: MILLER (G.), Catalogue of the Mammals of Western Europe. British Mus. (Nat. Hist.). London: I-XV, MURARIU (D.), CI. Mammalia. In: Contributions la connaissance de la faune du DBpartement Vrancea. Trav. Mus. Hist. nat. egrigore Antipaw, 17: MURARIU (D.), ANDREESCU (IOANA) Notes on the ecology of some representatives of the Orders Insectivora and Rodentia (Mammalia) from Vrancea, Budu, Prahova and Argq districts (Romania). Trav. Mus. Hist. nat. "Grigore Antipa", 20: SERAFINSKI (W.), Ecological structures of the species in mammals. 11. The intraspecific differentiation of the red bank vole (Clethrionomys glareolus Schreb.) in the Light of environmental conditions. Ekol. POL, 17,8: SIMIONESCU (VIORICA), Morphological analysis of mountain and lowland populations of Clethrionomys glareolus (Schreber, 1780) in Romania. Anmrul Muz. St. Nat. Piatra- Neamf, Ser. Bot.-Zool., 4: Received: 24 may 1993 Muzeul de Istorie Naturals, Grigore Antipa" $os. Kiseleff nr Bucurqti, ot 2 Romilnia