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Olexander Zhukov, Olga Kunah, Yulia Dubinina and Victoria Novikova

Abstract

The article presents the results of evaluation of the role of edaphic and vegetation factors on beta diversity of soil macrofauna by means of the MDM-approach. The multinomial diversity model (MDM) is a method for relating the Shannon diversity to ecological factors. The research was conducted in the ‘Dnipro-Orils’kiy’ Nature Reserve (Ukraine). The research polygon was laid in the forest within the Orlova ravine (48º31’13 “N, 34º48”15 “E). The study site comprises 1.0 ha of deciduous woodland bordered by an area of herbaceous cover within the ravine. In the soil of the studied polygon, 38 species of soil invertebrates were identified, which characterizes the gamma diversity. Alpha diversity, or the number of species on average at each sample point is 4.3. Beta diversity is 8.8. The principal component analysis of the edaphic parameters revealed four statistically significant principal components. For vegetation characteristics, six statistically significant principal components were identified. The sequential analysis of the effects shows that edaphic factors accounted for 20.9% (0.81 bit) of the available entropy (1.71–0.91). The largest decrease in the community entropy takes place under the action of the principal components 2 and 3 (0.06 bit and 0.05, respectively). A permutation test showed that these effects are statistically significant. In turn, 28.4% of the community β-diversity is attributable to vegetation factors. The greatest decrease in community entropy is related to the principal vegetation components 1, 3 and 4 (0.07, 0.05 and 0.04 bits, respectively). A permutation test indicated that this effect is statistically reliable. Geostatistical models substantially describe the varying effects on the beta-diversity of edaphic principal components 1 and 2, and the vegetation principal components 1 and 3. It was found that edaphic and plant factors play an important role in structuring the communities of soil macrofauna on the level of beta diversity. Community sensitivity to environmental factors varies in space and is spatially structured. For different environmental factors, specific spatial patterns of community sensitivity are allocated. Beta diversity may be due to the fact that the species of soil macrofauna communities also vary in the degree of sensitivity to various environmental factors. The species of soil microfauna are also divided according to their extent of sensitivity to different ecological factors.

Open access

Oleksandr V. Zhukov, Olga M. Kunah, Yuliya Y. Dubinina and Viktoriya O. Novikova

Abstract

This paper examines the role of ecological factors, derived from principal component analysis performed on edaphic and vegetational dataset as well as spatial variables, in structuring the soil macrofauna community of the Dnipro floodplain within the ‘Dnipro-Orilsky’ Nature Reserve (Ukraine). The soil macrofauna was defined as invertebrates visible to the naked eye (macroscopic organisms). The test points formed a regular grid with a mesh size of 3 m with 7 × 15 dimensions. Thus, the total test point number was 105. At each point, soil-zoological samples of 0.25 × 0.25 m were taken for quantifying the soil macrofauna. The spatial structure was modeled by a set of independent spatial patterns obtained by means of principal coordinates of neighbor matrices analysis (PCNM-variables). Spatial PCNM-variables explain significantly more variations of the community (19.9%) than edaphic factors (4.1%) and vegetation factors (3.2%). Spatial and combined environmental and spatial effects were divided into three components: broad-scale component was characterized by periodicity of spatial variation with a wavelength of 24.0–44.5 m, medium-scale – 11.1–20 m, fine-scale – 6.6–11.0 m. For a broad-scale component, environmental factors of a vegetational nature are more important, for medium-scale, edaphic factors are more important, for fine-scale, both vegetation and edaphic are important. For litter-dwelling animals, the most characteristic spatial patterns are on the broad and medium-scale levels. For endogeic and anecic animals, the most significant variability is on the fine-scale level.

Open access

Olexander Zhukov, Olga Kunah, Yulia Dubinina, Dmitry Ganga and Galina Zadorozhnaya

Abstract

This article presents the features of the phylogenetic organization of the plant communities of the Dnieper River terrace within the ‘Dnieper-Orilskiy’ Nature Reserve and the patterns of its spatial variation involving remote sensing data of the Earth’s surface. The research materials were collected in the period 2012−2016 from within the nature reserve. The research polygon is within the first terrace (arena) of the Dnieper valley. Sandy steppe, meadow, forest and marsh communities within the Protoch river floodplain and the Orlova ravine, as well as artificial pine plantations were the habitats present within the research polygon. The vegetation description was carried out on 10×10 m (100 m2) plots. A total of 94 geobotanical descriptions were made. Data on plant phylogeny was obtained by the Phylomatic service. Phylogenetic diversity of the communities was assessed by the Faith, Simpson and Shannon indices. Phylogenetic analysis was performed by means of a double principal coordinate analysis (DPCoA). The vegetation cover within the investigated polygon was represented by 189 species. Abundance Phylogenetic Deviation (APD) for the investigated metacommunity was evaluated to −0.53, which is statistically significantly different from random alternatives (p = 0.001). The APD negative value indicates that phylogenetic organization of the investigated metacommunity is overdispersed. The permutation procedure allowed us to establish that the eigenvalues of the DPCoA-axes obtained as a result of the real phylogenetic tree were significantly higher than their own number for the random phylogenetic trees for the first seven axes. This indicates that the first seven axes are useful for additional information on the ordination structure of the metacommunity.