Threat Status and Distribution of the Earthworm Genus Helodrilus Hoffmeister, 1845; Sensu Zicsi 1985, on the Balkans and the Neighboring Regions

Abstract

To assess the conservation status of the Balkans earthworm species from genus Helodrilus and to establish priorities for conservation, we propose an objective and sensitive separate analysis based on the Conservation Priority Index (CPI). Validity of the threatened species in our ranking system was tested by comparing the results with the IUCN (2001) Red List Categories and Criteria: version 3.1. IUCN Species Survival Commission. IUCN, Gland Switzerland and Cambridge, UK. Species were ranked according to their CPI taking into consideration a set of 9 variables (distribution, endemicity, vegetation zones, persistence, density rarity, rarity of occupancy, locality concentration, habitat specificity and habitat rarity). Each of variables was categorized into five ranks (0–4) of increasing risk for survival. The overall score (CPI index) for each species was the sum of all scores for each variable. The index can take values ranging from 0 to 36. We classified threatened species (CPI≥17) in three IUCN (2001) categories. Vulnerable, Endangered and Critically Endangered. All species that had proved to be the VU, EN or CR category according to IUCN (2001) also had a CPI value high enough to be included in some of the categories discussed above (CPI≥17). Our expertise shows that the species which need urgent action are: H. mozsaryorum (CR or EX), H kratochvili (CR), H. deficiens (EN) and H. balcanicus plavensis (EN). H. dinaricus, H. ospensis, H. serbicus, H. jadronensis, H. duhlinskae, H. vagneri, H. slovenicus and H. italicus were known only from the type locality, so we included these species only in suspect CR.