Monitoring studies of Collembola (Hexapoda: Collembola) on the forest-steppe transect of the «Privolzhskaya lesostep» Reserve (Penza region, Russia)

Study Extent

The diversity and population density of springtails were investigated on the Kuncherovsky site of the “Privolzhskaya Lesosteppe” natural reserve, located in the south-west of the Volga Upland. The records were carried out annually from 2009 to 2022 (excluding 2012, 2013). The data on the numbers for 102 species from 7 biotopes are presented (32203 specimens from 1030 samples).

Sampling

The Dnieper glaciation did not reach the territory of Kuncherovsky site of the “Privolzhskaya Lesosteppe” reserve. Despite the light granulometric composition of the parent rocks, soil formation process here according to the chernozem type with developing of chernozem soils on sandy sediments ("underdeveloped low-power light loamy chernozems") (Sileva, Chernova, 1999). There are no fundamental differences in the typical diversity of soil cover between forest and steppe areas of the Kuncherovsky forest-steppe (Belobrov et al., 2012). Under the steppe vegetation, there are underdeveloped low-power light loamy chernozems, leached medium-sized medium loamy chernozems in the marginal and forest biotopes, and incomplete low-power sandy loam chernozems on the slopes. The sites for collecting of soil microarthropods lay within the geobotanical monitoring transect (the data of botanical descriptions given in the Nature Chronicle of the reserve (Leonova, Novikova, 2012; Kudryavtsev, 2019) and used in the corresponding reviews (Novikova, Pan’kina, 2013; Pankina et al., 2015). Sample plots for soil microarthropods, 10 sq. m each were selected in biotopes of the forest steppe ecotone: dry xerophytic steppe (T) – meadow steppe (C) – steppe border biotope (A) – forest border biotope (B) – oak forest (D) – clearing with individual birch trees (Cl) – aspen forest (O). Short designations/names of the sampling plots and overview information were published (Shveenkova, 2010, 2016, 2018, 2022). More detailed descriptions based on botanical data (Leonova, Novikova, 2012) are given here. These descriptions of the transect are given based on the geobotanical survey of 2005-2006 (Leonova, Novikova, 2012). However, successional changes occur regularly, affecting not only the abovesoil cover, but also the upper tree layer (for example, aspen trees fell intensively after a severe drought in 2010, and due to the old age of tree species). The sampling plot “Xerophytic steppe – fescue (T)” is a dry steppe in sandy soil (incomplete low-power sandy loam chernozems). The overall projective coverage is very low (28%). A small number of species are found in the association (Festuca polesica (8%), Stipa borysthenica (2%); Potentilla argentea (10%), Artemisia campestris (4%), etc). The sampling plot “Meadow steppe - gramineae grass (C)”. (Soil – underdeveloped low-power light loamy chernozems). The total projective coverage is 53%. The association is dominated by gramineae Brachypodium pinnatum (25 %), also by Geranium sanguineum (8%), supplemented with Stipa pennata (2 %) и S. tirsa (2 %), Trifolium alpestre (3%), Potentilla alba (3%), etc. The sampling plot “Steppe border biotope (A)” (soil – leached medium-sized medium loamy chernozems), is represented by a gramineae meadow with rare undergrowth of trees (young trees of pine, oak), shrubs (broom) on the border of the forest (woodland). The total projective coverage is about 61%. The association is dominated by Geranium sanguineum (10%), Calamagrostis epigeios (5%), supplemented with Dactylis glomerata (2%), Coronilla varia (3%), etc. The sampling plot “Forest border biotope” (soil – leached medium-sized medium loamy chernozems), is represented by a clearing with individual trees (Quercus robur, Betula pendula), in the undergrowth presented Acer platanoides, Euonymis verrucosus, Rhamnus cathartica, Cerasus fruticosa. The total projective coverage of the abovesoil cover is about 45% (Brachypodium pinnatum (10 %), Calamagrostis arundinacea (3%), Fragaria vesca (6%), Betonica officinalis (5%), Pyrethrum corymbosum (5%), Heracleum sibiricum (4%), etc.). The sampling plot “Forest oak” (soil – leached medium-sized medium loamy chernozems), it is oak forest (Quercus robur, the projective coverage is 70%); in the undergrowth is only Euonymis verrucosus (the projective coverage is 60%), the poor abovesoil cover is also formed by a Euonymis verrucosus (15%) and Convallaria majalis (5%). The sampling plot “Clearing with individual birch trees” (soil – leached medium-sized medium loamy chernozems), is a clearing in the woodland. Birch (Betula pendula) and oak trees (Quercus robur) are located on the borders of the clearing; Acer platanoides presented in the undergrowth, the projective coverage of abovesoil cover is about 34% (it’s consist of Aegopodium podagraria (10%), Convallaria majalis (8%), Pteridium aquilinum (15%), etc.). The sampling plot “Aspen forest” (soil – leached medium-sized medium loamy chernozems), it is aspen forest (Populus tremula, the projective coverage is 80%), in the undergrowth are Acer platanoides (20%), Euonymis verrucosus (15%), Tilia cordata (40%); abovesoil cover formed by a Aegopodium podagraria (12%), Convallaria majalis (6%), Pteridium aquilinum (4%), etc. Ten soil samples down to 10 cm were taken from each biotope, using a core sampler ~ 5,6 cm in diameter (a corer of 25 sq. cm), from one to three times a year (in spring, summer and autumn; in spring and autumn; or only in autumn). In open biotopes (T, C, A) ten sampling points were randomly located within a sample plot of 10 sq. m. In the forests (D, O), the forest border biotope (B) and in the overgrown clearing (Cl), ten sampling points are arranged in two sampling lines – 5 samples each between randomly selected two pairs of trees (trees I-II include samples 1-5; trees III-IV include samples 6-10). Each sampling line include two samples at the base of the tree (samples 1, 5, 6, 10, respectively), two samples in the crown projection (corresponding to samples 2, 4, 7, 9) and one sample in the "window" between the trees (samples 3, 8). The springtails were extracted into 70% alcohol by the Tullgren funnel method. The material was mounted on slides in Phoera liquid according to a standard procedure (Ghilarov, 1975; Potapov, Kuznetsova, 2011). Some species were described as new for the science from the material of the monitoring survey or from these biotopes: Stachorutes gracilis sp. n. (Smolis & Shvejonkova, 2006), Oligaphorura stojkoae sp. n. (Shvejonkova & Potapov, 2012), O. mazeii sp. n. and O. psammophila sp. n. (Shveenkova & Babenko, 2021). Data on species were digitized, standardized, the quality of data was checked and errors were corrected, and then published.

Quality Control

We used modern taxonomic papers and key by Martynova (1964) for the taxonomic determination of the material.

Method steps

1. The mosaic pattern of forest-steppe landscapes is associated with actively successions and a variety of edge systems - ecotones on the borders of steppe formations and woodlands. This paper presents a long-term period of research of soil microarthropods on the forest-steppe transect of the protected area. What is the reaction of soil biota and how do soil microarthropods reflect current changes in the terrestrial environment? Clarification of these issues is one of the aspects of long-term monitoring. So the fires of 2010 and the subsequent drought led to significant changes in forest and steppe biocenoses. Based on the results of monitoring, respectively, a decrease in the species richness and abundance of soil microarthropods was recorded. On the other hand, the tasks of identifying the species richness and biodiversity of soil-dwelling Collembola in the forest-steppe zone are being solved. The analysis of specific diversity data at the low level (alpha- or biotopic diversity), allows to build the corresponding values in the higher scale (gamma - on the transect as a whole and in the region). So, in separate records, from 8-12 to 22-29 Collembola species were detected in various biotopes of the transect, about 50 species were registered on the transect as a whole for accounting. A total of 102 types of Collembola were identified on the transect during the study period. These data make a significant contribution to the faunal list of Collembola of the forest-steppe of the Middle Volga region (at least 200 species). Primary data on the abundance and species composition of Collembola in individual samples will further calculated various indexes of differentiating diversity, which is rather high for various organisms in the forest-steppe zone.

1. Arthropoda
   rank: phylum

1. Collembola
   rank: class

European part of Russia, Middle Volga region