Assessment of the Distribution of the Subendemic Species of Earthworms in the Forest Belt of the Northwestern Caucasus under Various Climate Change Scenarios

Ongoing climate change affects soils and soil invertebrates primarily through changes in temperature and precipitation patterns. The aim of this work is to evaluate ecological and geographical models of the distribution of earthworm species, constructed using the method of bioclimatic modeling using various climate scenarios. Modeling of the ranges of two subendemic species of earthworms, which are currently most widespread in the forest ecosystems of the Northwest Caucasus, was carried out: Dendrobaena sсhmidti (the epi-endogeic and endogeic forms were studied separately) and D. nassonovi (anecic form). The modeling was carried out on the basis of in-kind data on the detection of species and forms obtained during expedition routes from 2014 to 2019, completed from the lower to the upper forest line, in the territory of the Northwest Caucasus. In total, 1028 geographical points were surveyed, of which the epi-endogeic form of D. sсhmidti was found in 105 locations, endogeic species in 575 locations, and anecic species of D. nassonovi at 185. Models were built up to 2070 using Maxent 3.4.4 software. Scenarios based on changes in greenhouse gas concentrations were used as predictive estimates of future climate change: RCP 2.6, RCP 4.5, RCP 6.0, and RCP 8.5. It has been shown that the studied species of earthworms belonging to three morpho-ecological groups are vulnerable to rising temperatures in combination with a decrease in the amount of precipitation, as well as to uneven precipitation, which is reflected in the reduction of the area of potential ranges in the most suitable habitat conditions for these species of earthworms under different climatic scenarios, especially the “harshest” ones – RCP 6.0 and RCP 8.5.