Vol 50, No 4 (2019)

Analysis of the age structure of Dahurian larch (Larix gmelinii Rupr.) forests in the western part of the Putorana Plateau (Sukhie Gory Range) and comparison of diachronous topographic maps and satellite images have revealed changes in the altitudinal position of the upper boundary of tree vegetation. The most significant changes occurred on south- and southwest-facing slopes. Correlations of trunk diameters with the phytomass of trees and its fractions have been found. The course of changes in the structure and phytomass of tree stands in the upper timberline over the past centuries has been reconstructed. Forest expansion has been facilitated by the general change in climate conditions (warming) in the study area.

Based on the analysis of dose–response relationships under exposure to a wide range of copper sulfate concentrations, the metal tolerance of seed progeny was assessed using the root elongation test in two morphological forms of Taraxacum officinale Wigg. s.l. growing in background and technogenically transformed areas (industrial waste dumps). Since previous studies in the same areas showed that these forms differed in their abundance and ratio in the coenopopulations and in the level of copper accumulation, it was assumed that they would also differ in the metal tolerance of seed progeny. It was found that the average values of effective copper sulfate concentrations inhibiting root growth in seedlings by 10, 50, and 90%, did not differ between the study areas and between the morphological forms of dandelion.

Studies in the northern forest–tundra of Siberia have been performed to estimate temperature conditions in individual months of the growing season that have an effect on the formation of light tree rings in three larch species: Larix sibirica, L. gmelinii, and L. cajanderi. The threshold air temperatures for light ring formation have been determined and found to be similar in all the species. Differences in temperature response are conditioned mainly by the longitudinal climate gradient rather than by species-specific features.

A simultaneous analysis of the chronographic variation of the mandible of bank vole (Clethrionomys glareolus Shreb.) in three longitudinally distant populations that inhabit floodplain forests of Sakmara and Samara rivers in the south of the species range (Orenburg oblast) has revealed significant morphogenetic and morphofunctional changes in each of these populations over 33 years. Changes in the shape of the mandible in allochronous vole samples (1983 and 2015) have been detected using methods of geometric morphometrics. Morphofunctional rearrangements have been assessed based on mandibular indices, which characterize differences in the structure of the mandible resulting from changes in functional loads after a shift in diet. Significant changes in the mandible shape and in the values of these indices have occurred in all allochronous populations. Chronographic variation in the mandible shape in all populations has similar direction in the morphospace; its range exceeds that of geographic variation and reflects a significant historical rearrangement of morphogenesis. The authors discuss the probable relationship of rapid morphogenetic and morphofunctional changes in vole mandibles to the transformation of local trophic conditions caused by different directions of plant successions, which, in turn, are related to local trends of climate changes.

Communities of soil animals (meso- and macrofauna) in rice paddies tend to be fragmented, and have extremely low abundance. Nevertheless, some groups, such as enchytraeids, may become dominant in flooded conditions, as shown in tropical rice agroecosystems. However, the fauna and functional composition of enchytraeids (Annelida, Clitellata, Enchytraeidae) under such conditions have not yet been studied at temperate latitudes. We have investigated enchytraeid communities and the ratio of their functional groups in the main rice-growing regions of Russia: Krasnodar krai, Primorsky krai, and the Republic of Kalmykia. Samples were taken in summer–early autumn of 2016 in four habitat types: flooded rice paddies, drained paddies occupied by upland crops, adjacent bunds, and undisturbed grasslands (control). Generalized linear model analysis showed that the factor habitat type and its interaction with the factor region had a significant effect on the total enchytraeid abundance, with the factor region alone having no such effect. Their abundance was the highest in the control habitats and bunds (mean and standard error for all the regions: 3278 ± 1131 and 3255 ± 762 ind./m², respectively), being insignificantly lower in the paddies under upland crops (1282 ± 850 ind./m²) and decreasing to a minimum of 415 ± 323 ind./m² in the flooded paddies. A comparison between the last two habitat types shows that enchytraeids can relatively quickly restore their abundance in the rice paddies after draining. Principal component analysis revealed a positive correlation between the density of enchytraeids belonging to basophilous ecological group and bioavailable phosphorus content. The correlation between the abundance of acidophilous enchytraeids and this parameter was negative. Thus, the abundance ratio of enchytraeid ecological groups could be used as an informative indicator of the concentrations of nutrient elements and depends on physical and chemical characteristics of paddy soils. Despite the low abundance of enchytraeids in these soils, they can be an important component of the detrital food webs during periods of paddy-drainage in intensive rice agroecosystems at temperate latitudes.

We describe here for the first time the body size and age of the Common Toad (Bufo bufo) from high (Trabzon, 1090 m and Kastamonu, 925 m above sea level) and low (Yalova, 65 m above sea level) altitudes in Turkey using skeletochronology. The specimens from Trabzon were significantly smaller and younger than the ones from the Kastamonu and Yalova populations. Age at sexual maturity was three years for females while it varied between two to three years in males in all three populations. We found the females to be significantly larger than males in all three populations. The sexual dimorphism indices (SDI) were biased toward the female populations. Even after accounting for the influence of age, the snout-vent length (SVL) differed significantly among the populations. Age and SVL were closely correlated in the male populations for all the three localities (Yalova, Kastamonu, and Trabzon) and for female individuals in the Trabzon population. In this first report, we reveal the demographic structure of B. bufo from the Anatolia region in Turkey and provide comparative data regarding this species for further discussion and determined that age and body size of Common Toad not differentiated among different altitudes.