NEW RECORDS AND REMARKS ON EARTHWORMS OF THE VOJVODINA PROVINCE (OLIGOCHAETA: LUMBRICIDAE, CRIODRILIDAE)

The aim of this paper is to present the results of the recent collecting earthworms, with new localities and new habitats in Vojvodina Province. The sporadic field investigation was carried out during 2013-2020. In this paper we report new records of Criodrilus lacuum Hoffmeister, 1845 (family Criodrilidae) proved to be new species for the fauna of Vojvodina Province. Also, information on the taxonomic status of individual species was provided. Fifteen earthworm species and subspecies from family Lumbricidae have been registered. Six taxa were found to be synonymous with nominal species, so that the number decreases to 31 species, from 10 genera. Our data demonstrate clearly that the earthworm fauna of the Vojvodina Province is relatively poor, monotonous and that the impact of intensification of agricultural practices effect on loss of soil biodiversity.


INTRODUCTION
Vojvodina Province is extremely flat area formed after the swelling of the Pannonian Sea. It is situated in the southeastern part of the Pannonian plain. The monotony of the plain break up rivers, canals, sandstone, loess plateau, different crops and other vegetation, densely distributed settlements, and two mountains, whose height barely exceed the upper limit of the hills, and all this gives a special landscape appearance. Natural vegetation is still dominant in only a few very restricted areas. Agriculture, forestry, urbanization, and water management have had profound influences on the distribution, structure, and quality of habitats and species. For these reasons formed several protected areas such as: Fruška Gora Mountain, the Vršac Mountains (also known as Vršac Hill), Danube Basin and Zasavica. Тhe protected areas which represent a major wildlife refuge have a great importance for the preservation of biodiversity (CSUZDI, 1995;ZICSI et al., 1999;BÁLDI, 2003 While the taxonomic composition and distribution of earthworms of certain parts of the Pannonian Plain are well known (POP, 1948(POP, , 1949ZICSI, 1991;MRŠIĆ, 1991;CSUZDI and ZICSI, 2003;POP et al., 2010;CSUZDI et al., 2011;SZEDERJESI, 2011), some parts of the region have not been widely studied. Research of earthworms in Vojvodina Province were started at the beginning of the XX century (SZÜTS, 1919;ČERNOSVITOV, 1938). ZICSI (1972) and ŠAPKAREV (1978) continued to work on Lumbricidae Vojvodina Province.  Šapkarev, 1989, Aporrectodea macvensis (Šapkarev, 1987), Dendrobaena veneta veneta (Rosa, 1886), Bimastos rubidus (Eisen, 1874), Lumbricus friendi Cognetti, 1904, Octodrilus gradinescui (Pop, 1938), Octolasion cyaneum (Savigny, 1826) and Proctodrilus opisthoductus Zicsi, 1985 and two of these species were identified for the first time throughout the whole territory of Serbia (L. friendi and O. gradinescui).
This list of earthworms of Vojvodina Province included 31 species belonging to 10 genera. However, the difference in the number of species between the last work from 2014 and the present checklist is a result of the fact that two taxa were found to be synonymous with nominal species (STOJANOVIĆ et al., 2020). Also, four subspecies was found to be synonymous to the nominal species already reported for the Pannonian Plain.
In that respect, one of our aims has been to present the results of the recent collecting, with a new localities and a new habitats. Another aim was to present the valuable data that we came across from the old collection of our Institute. We report the first record of Criodrilus lacuum Hoffmeister, 1845, in Serbia, thus updating the knowledges of its geographical range.

MATERIALS AND METHODS
Our investigations were carried out in the Vojvodina Province, located in the northern part state of Serbia (44°38'-46°10'N; 18°10'-21°15'E) (Fig. 1). Vojvodina extends to the southern part of the Pannonian Region and is a predominantly flat area with two mountain ranges, Fruška gora Mt. and Vršac Mts. Fruška Gora is a low island mountain, located at 502 m.a.s.l., while Vršac Mts. is a low island mountain, located at 641 m.a.s.l. Its valleys are covered by meadows, while its highest parts are covered by the dense deciduous forests. The climate is temperate-continental with central-European and Mediterranean influences. More than 75% of the territory is occupied by agricultural fields which alternate with forests, meadows and pastures.
The sporadic field investigation was carried out during 2013-2020. Over the last investigation period, from all over the territory, we were collecting earthworms from various habitats which included natural biotopes (oak forest, wet meadow, under the stump, near the river, near the stream, mud) and artificial biotopes (garden and agricultural field).
Earthworms were collected using the diluted formaldehyde method complemented with digging (0.4x0.4 m quadrates) and hand sorting as well as turning over rocks, debris and logs. The earthworms were killed in 70% ethanol, immediately fixed in 4% formalin solution and transferred and stored in 90% ethanol.

RESULTS AND DISCUSSION
During the present study, 15 species and subspecies of earthworms from family Lumbricidae have been registered in Vojvodina Province (Tab. 1). Six taxa were found to be synonymous with nominal species (Tab. 2). By combining these new findings with the previous studies SZEDERJESI et al., 2014), the number of species from family Lumbricidae known to be occurring in the studied region decreases to 31 species from 10 genera. Also, Criodrilus lacuum from the family Criodrilidae proved to be new for the fauna of Vojvodina Provance (Tab. 1).
In the Vojvodina Province, according to our results, the most common species is Aporrectodea chlorotica (Savigny, 1826) which occurs only in the agricultural field and it is a typical synanthropic species. The next most common species are: Ap. trapezoides (Dugès, 1828), Ap. rosea (Savigny, 1826) and Lumbricus terrestris Linnaeus, 1758. High abundance in this group of species reflects their reproductive capacity and the potential to adapt and colonization (Bouché, 1977;Satchell, 1980). Based on the study that was conducted , it can be observed a correlation between the type of habitats and species of earthworms that occur in them. In our researches, there are a lot of agricultural habitats, which are characteristic for these еаrthworm species (Schmidt et al., 2001(Schmidt et al., , 2003Krück et al., 2006;Scullion et al., 2006;Pelosi et al., 2009a, b). In particular, Ap. trapezoides and Ap. rosea occur commonly in soils used for grain production (Baker et al., 2003). Otherwise, cropping systems thus modify the functional composition of earthworms (Pelosi et al., 2009b).
The degree of endemism in the Pannonian area of Serbia is relatively low, with five taxa (three Dacian and two Balkanic endemics) (STOJANOVIĆ et al., 2020) Karaman, 1968 and Aporrectodea macvensis (Šapkarev, 1987), belong to the broad range Balkan endemic species, registered in the Balkan part of Serbia and in the only one locality on the border between the Pannonian Plain and the Balkan Peninsula (STOJANOVIĆ and MILUTINOVIĆ, 2014). Allolobophora kosowensis has been registered mainly in the southern and southeastern part of Serbia. Based on the distribution data of this species, it is certain that it is the hilly area of Serbia around the river Velika Morava possible migratory road to the northernmost point of its distribution on the perimeter Pannonian Basin. Aporrectodea macvensis is a rare endemic species. It is represented mainly in the western and northern part Balkan part of Serbia ( , 2011). On the other hand, due to the agriculture impacts, the earthworm fauna of the Vojvodina Province is on the distinct stress of anthropogenic factors which are unification of living conditions. Therefore, it is understandable that the number of endemic earthworms from Pannonian part of Serbia is quite low compared with the 25 endemic taxa recorded from the Balkan part of Serbia (STOJANOVIĆ et al., 2020). Only one Dacian endemic, O. gradinescui does not present in the Balkan part of Serbia. Four other endemics from Vojvodina Province exist in the Balkan part of Serbia, as well. Despite of the fact that is the Vojvodina Province is a much smaller part of the country, our data demonstrate clearly that the earthworm fauna of the Vojvodina Province is relatively poor and monotonous. It is clear that the impact of intensification of agricultural practices effect on loss of soil biodiversity (HOLE et al., 2005) and therefore it is not surprising that peregrine species are predominant. On the other hand, we cannot ignore the fact that the Balkan Peninsula is a specific region with frequent changes in global ecological conditions throughout geological history that have greatly contributed to the occurrence of an exceptionally heterogenous fauna in this area (MRŠIĆ, 1991). However, instead of prevalence of distinctly uniform agrobiotopes that affect on the unification of living conditions that strongly endanger biodiversity in Vojvodina, there are still natural areas which deserve protection, and that could maintain the functioning of natural ecosystems and act as refuge for earthworm species.