The present paper records new and poorly known myriapods (Diplopoda, Chilopoda) collected in Bulgaria in the last 10 years. Four new species are reported as new to the Bulgarian fauna: Lithobius melanops Newport, 1845 (Chilopoda: Lithobiomorpha: Lithodiidae), Polydesmus collaris C.L. Koch, 1847, Polydesmus inconstans Latzel, 1884 and Polydesmus schaessburgensis Verhoeff, 1898 (Diplopoda: Polydesmida: Polydesmidae). Scanning electron micrographs of the gonopods and male leg-pairs 5 and 6 are provided for the first time for Bulgarosoma superficiei Strasser, 1975, a species hitherto known only from its original description. This article presents also an updated list of Myriapoda in Bulgaria. The list includes a total of 251 (sub-)species of the classes Diplopoda (127), Chilopoda (104), Pauropoda (18) and Symphyla (2).

The article presents the results of a study of the soil surface seasonal activity of two species of julidae, widely spread in the Balkan Peninsula: Leptoiulus trilineatus (C.L. Koch, 1847) and Megaphyllum trassylvanicum (Verhoeff, 1897). The material was collected by means of pitfall traps between May 2007 and May 2009 in natural and urban habitats exposed to varying degrees of anthropogenic pressure. In the study period 1474 specimens of L. trilineatus and 618 specimens of M. transsylvanicum were collected. The impact of the soil and air temperature and humidity on the seasonal activity of both species was measured through statistical analysis. The statistical data processing was conducted using SPSS 9.0 and StatPlus 3.5.3 software packages.L. trilineatus and M. trassylvanicum are polytopic, mesophilic and mesotermic species with year-round activity in the studied area. There is no statistically significant correlation between the degree of anthropogenic impact and the activity of the two species.Leptoiulus trilineatus shows equal preference for both urban and natural habitats in the studied area. The species demonstrates the typical of all millipedes bimodal activity, which is the highest in spring and the beginning of winter – in the periods from March to May and from November to December. The coefficients of correlation dependence of L. trilineatus activity on the tested abiotic environmental factors are not statistically significant. The Pearson-Brave coefficient which measures the effect of soil humidity on species activity is 0.417, which shows a positive correlation. M. trassylvanicum has the highest frequency in urban biotops such as parks in the urban and suburban areas of Shumen and in the coniferous habitats on the Shumen Plateau. In this area the species demonstrates its highest activity in spring and summer (from February to July). The abiotic factors with statistically significant effect on the soil surface activity of M. trassylvanicum are the soil and air temperature – the values of the Pearson-Brave correlation coefficients are 0.708 and 0.586 respectively.

ABSTRACT

At present, the inventory lists of the Myriapoda of many geographical areas in Bulgaria and the comparative analyzes of the similarity between such local faunas are scarce or completely missing. The present paper presents the results of the comparative analysis of α- and β-diversity of the myriapoda communities in natural habitats in two regions in Northeastern Bulgaria – the Shumen Plateau and the Madara Plateau. The compared habitats in these plateaus have similar geographical, soil and climatic conditions, and similar species composition of plant formations. The analysis of the structure of the myriapoda communities included estimation of species diversity by determining the Shannon-Wiever index (H’) and the Berger-Parker index (d). The degree of similarity between the species composition of the communities was analyzed by the Czekanowski-Dice-Sörensen, Jaccard, Bray-Curtis, Horn, Morisita-Horn indices and the corrected Chao-Sörensen and Chao-Jaccard indices. The species diversity of the millipede community in the Shumen Plateau is much greater than that of the Madara Plateau, while the diversity of the centipede communities in the two plateaus does not differ significantly. In both classes the greatest species diversity is registered in deciduous and mixed deciduous-coniferous forests. Chao-Sörensen and Chao-Jaccard indices of similarity for the myriapod communities in these habitats are the highest, approaching 1, in contrast to the other sites where the registered species composition of the centipedes is smaller and the degree of similarity is about 0.6.

Keywords: nitrates, nitrites, pollution of soils, soil types IntroductionStudies conducted over the last 20-25 years have confirmed the need for a thorough research of the composition and properties of soil solution, since this dynamic component of the soil is particularly sensitive to the changes caused by different factors, and can therefore be used as a criterion for measuring the risk of overloading each of agroecosystems' components -soil, vegetation and waters [1,2].