Preliminary Estimation of the Influence of Cydalima perspectalis Invasion on the Species Composition and Structure of Earthworm Population (Oligochaeta: Lumbricidae, Acanthodrilidae) in the Range of Buxus sempervirens (Western Caucasus)

The earthworm fauna and population structure in Colchic ecosystems of the southern slope in the Western Caucasus were studied. First, in May 2013 we have sampled earthworms of the forest communities. This research was repeated in 2018 after Buxus sempervirens L. destruction by Cydalima perspectalis Walker (Lepidoptera, Crambidae). Altogether 13 earthworm species were registered in the soils of original B. sempervirens phytocenose and derived phytocenoses of the Western Caucasus. Endemicity of earthworms in the study area was higher than in most regions of Russia. The earthworm samples in 2013 and 2018 were similar in species composition, but differed in terms of dominant species. The structure of the earthworm population in the soils of the secondary phytocenoses has become closer to the earthworm communities of the other forests in the Western Caucasus. Analysis of the relative position of taxocenes in 2013 and 2018 space NMDS model, allows to put forward a hypothesis about the reduction of their total ecological niche after the disappearance of B. sempervirens. We believe that a broader ecological niche in 2013 is associated with a greater mosaicism (diversity) of the worm habitat formed by boxwood communities.

Automated summary

The earthworm fauna and population structure in the Colchic ecosystems of the Western Caucasus were investigated. 13 earthworm species were identified, with higher endemism compared to other regions in Russia. The composition of the earthworm samples in 2013 and 2018 was similar, but dominant species differed. The earthworm population in the secondary phytocenoses became more similar to other forests in the region.