PERIODICUM BIOLOGORUM UDC 57:61 VOL. 116, No 3, 303–312, 2014 CODEN PDBIAD ISSN 0031-5362 Original scientific paper Characterisic soil mite’s communities (Acari: Gamasina) for some natural forests from Bucegi Natural Park – Romania ABSTRACT MINODORA MANU1 STELIAN ION2 Background and Purpose: One of the most important characteristics 1Romanian Academy, Institute of Biology, of a natural ecosystem is its stability, due to the species’ and communities’ Department of Ecology, Taxonomy and diversity. Natural forest composition model constitute the main task of the Nature Conservation, street Splaiul Independentsei, present-day management plans. Soil mites are one of the most abundant no. 296, PO-BOX 56-53 edaphic communities, with an important direct and indirect role in decom- 0603100, Bucharest, Romania posing, being considered bioindicators for terrestrial ecosystems. The aim of 2Romanian Academy, Institute of Statistics and the paper was to identify characteristics of soil mites community’s structure. Applied Mathematics “Gheorghe Mihoc-Caius Iacob” – ISMMA Materials and Methods: Soil mites community’s structure (composition street Calea 13 Septembrie, no. 13, sector 5, of the species assemblage, abundance of the species, species associations and Bucharest, Romania interdependence between species) from three mature natural forest ecosys- E-mail: [email protected] tems, from Bucegi Natural Park -Romania, were analyzed using statistical Correspondence: analyses, which combine two different methods: cluster analysis and correla- Minodora Manu tions. Romanian Academy, Institute of Biology Results: Two different species associations were described. One of them Department of Ecology, Taxonomy and Nature Conservation was identified as stable association in a hierarchical cluster and another, street Splaiul Independentsei, no. 296, PO-BOX 56-53 subset of the first, was composed by species pair wise positive correlate (mono- 0603100, Bucharest, Romania tonic associations). The number of species grouped in stable associations was E-mail: [email protected]; similar in both soil layers (OLF and OH), but different in every type of [email protected] ecosystems: lowest in fir forest, medium in spruce area and the highest in List of nonstandard abbreviations: beech forest. 66.6% of species from stable associations were included in OLF = litter-fermentation soil layer monotonic association. Veigaia nemorensis and Neopodocinum mrciaki OH = humus soil layer were common species for all investigated ecosystems, in both soil layers, as p = significance level well as for stable and monotonic associations. r = rank correlation Conclusions: The present study revealed that each type of ecosystem was characterised by a stable and monotonic associations. 24.74% from all iden- Key words: correlation, cluster, forest, gamasid, tified species were grouped in these associations. humus, litter. INTRODUCTION ATURAL forests are complex and stable ecosystems. Over time, Nthe structure and function of a natural ecosystem should remain relatively stable, even in the face of disturbance. These characteristics are due to factors that provide ecosystem’s stability, as: species diversity (interactions, life strategies), trophic complexity (food web structure) and nutrient or energy flux. On soil level, interrelations between soil microarthropods, influence physical, chemical and biological processes. Accepted November 14, 2014. These microarthropds are characterized by a great diversity, one of the most abundant groups being predatory soil mites (20, 21, 23, 39, 45). M. Manu and S. Ion Soil mite’s associations from natural forests Figure 1. Geographical position of Bucegi National Park, Romania ( = ecosystem with Abies alba; = ecosystem with Picea abies; = ecosys- tem with Fagus sylvatica). Additional informations concerning one of the soils (abiotic factors: soil temperature, humidity, pH, organic biological components of the terrestrial ecosystem consti- matter; biotic factors as vegetal association) and human tute an important database for the forest conservation, impacts, influenced the structure and dynamics of these especially in natural protected areas. Predatory soil mites invertebrates’ communities (8, 9, 10, 13, 14, 27, 28, 39, (Mesostigmata: Gamasina) are the main regulatory 41). mechanism for other soil invertebrates as i.e. springtails, The aim of the paper was to identify the structure of nematodes, enchytreides, oribatids. In the soil trophic studied mite communities (composition of the species as- web, mites are considered consumers from the third level semblage, abundance of the species, species associations (18, 19, 20). They are very mobile arthropods, capable to and interdependence between species) from three mature migrate in different habitats, favorable according to their natural forest ecosystems, from Romania, by combining ecological requirements. Peculiar environmental condi- two different methods: cluster analysis and Spearman cor- tions determine specific population structure. Any distur- relations. This study provides valuable information con- bance can induce quantitative (abundance) and qualita- cerning one of the most important soil invertebrate groups tive (species composition) modifications on soil mite from terrestrial ecosystems, taking into account that a communities. These modifications are specific “signals” “natural forest” composition model is the main goal of of the soil ecosystem changing, and gamasid mites could present-day management plans. be consider as one of the bioindicator group, with poten- tial to use in forestry practices. This is the reason that the gamasid could be considering one of bioindicators group MATERIAL AND METHODS for terrestrial ecosystems (7, 11, 26, 34, 38, 44). In Eu- Investigated area rope, as well as in Romania, studies of soil predatory mites from protected areas using population parameters (abun- One of the most important protected areas from Ro- dance, numerical density, constancy, dominance, species mania, having a rich diversity of flora and fauna is Buce- diversity) demonstrated that the environment conditions gi Natural Park (BNP). It is situated on the east side of 304 Period biol, Vol 116, No 3, 2014. Soil mite’s associations from natural forests M. Manu and S. Ion TABLe 1 Description of the investigated forest ecosystems from BNP. Characteristics Picea abies Abies alba Fagus sylvatica Geographical N = 45°21’09.15’’; N = 45°23’50.20’’ N = 45°20’56.45’’; Coordinates E = 25°31’10.59’’ E = 25°32’00.07’’ E = 25°31’24.9’’ Altitude 1350 m 950–1000 m 1200 m Exposure SE NV S Slope 45° 10°–15° 10° Area (ha) 12.9 16 3 Litter Continuous-very thin layer Continuous, 3–4 cm Continuous, 4–5 cm Brown eumesobasic, with Soil Mull-moder humus Rich in humus and sandy clayey-sandy fine texture Vegetal association Leucanthemum waldsteinii Oxalis-Pleurozium Oxalis-Dentaria-Asperula Actual composition 9 spruce: 1 beech 10 fir 10 beech Age (years) 110 150 110 Production class 4 2 3 Volume (mc/ha) 405 658 399 Growth (mc/ha) 3.5 5.9 4.6 Meridional Carpathians and includes whole Bucegi Mas- slides in Hoyer’s medium (21). Several mite specimens sif. This is developed in an amphitheater shape with a were dissected under a stereoscopic microscope after clear- wide south opening and limited by the peaks, which often ing in lactic acid. Each body part was mounted in Hoyer’s reach to 1000 m altitude, in comparison with adjacent medium or polyvinyl alcohol–lactic acid mixture (PVA) areas. The BNP has a total area by 32.663 ha (Figure 1). medium. The conservation of the gamasids fauna was made in an ethyl alcohol (70%). All identified species are The ecological investigation was made in 2001-2003, in mites’ collection of the Institute of Biology – Ecological in three forest ecosystems from BNP. The investigated Stationary from Posada. forest ecosystems are described below (Table 1) (6, 27, 28). Data processing Mite samples To perform the cluster analysis we build up a data The size of one sampling plot was 10000 m2 (1 ha). The matrix on the base of site observations. At each moment soil samples were collected monthly, with a random strat- of time there was 14 soil samples collected in each forest. ification method, using a square metal core (1000 cm3). One denotes by t i=1.24 the moment of time observa- Stratified sampling entails partitioning the soil sample i tions, by z a=1.14 the site of observation and by ya the into two subsamples, taking account of the soil layers: a ai number of individuals of the a-species recorded at the litter - fermentation layer (OLF) and humus layer (OH). time t and at the site z then the entries of the data matrix Each soil sample was divided into 500 cm3 subsamples. i a yi are given by. The surface of one soil sample was by 10*10 cm. The a aa depth of the sample was by 10 cm. In both years, 1008 yi =∑ y.ia soil samples were analyzed, divided in 2016 subsamples a (OLF and OH). An equal number of soil samples were To investigate the species association we use two dif- collected from all investigated ecosystems. The extraction ferent method, cluster analyses and Spearman rank cor- of the mites was made in 10-14 days, by Berlese –Tullgren relation. The cluster analysis is first performed to identify method, modified by Balogh (1972). The samples have one of more homogeneous groups of species and then we been kept in refrigerator, till next extraction. In all eco- study the correlations within each group. The second systems 97 species were identified, with 23441 individu-