The North Caucasus occupies the territory between the Kuma-Manych depression in the north, the Russian state border in the south, the Black and Azov seas in the west, and the Caspian Sea in the east. The Caucasus is located at the junction of temperate and subtropical climatic zones and is characterized by a developed network of communications and tourist clusters. Thus, the Russian part of the Caucasus territory is a “gateway” through which alien species can penetrate and spread throughout the region. In addition, the deliberate introduction of mammals was intensively carried out in the region in the 20th century.
For the central part of the North Caucasus, information is known on the status of populations of individual invasive species of mammals; there are publications about mammals that were introduced or introduced. This work aims to summarize information on alien mammals living in the central part of the North Caucasus and assess their role in the ecosystems of this region. The study area is characterized by high landscape and biotopic diversity and includes the territory of the Stavropol Territory, the Kabardino-Balkarian Republic, and the Republic of North Ossetia-Alania. The climate in the region is temperate continental. The territory covers about 87 thousand km2.
Mountain ecosystems, and the Caucasus in particular, are particularly vulnerable to biological invasions. What are the invasive mammal species in the North Caucasus and what is their role in the region’s ecosystems?
Marita Emkuzheva
Research results
In the ecosystems of the central part of the North Caucasus, invasive species are represented by two main categories: introduced in different ways (intentionally, unintentionally, including accidentally) and self-dispersing. The first group mainly includes hunting objects of different taxonomic levels (species, subspecies) introduced by humans into the fauna of a region unusual for these animals. The second group is represented by taxa expanding their natural range for various reasons without direct human intervention.
Diversity of alien mammals in the region
The taxonomic diversity of alien mammals in the central part of the North Caucasus is represented by 16 species from 4 orders. Among them are artiodactyls – 44%, slightly less carnivores – 31%, rodents make up 19%, and about 6% are chiropterans.
According to the vectors of introduction into the fauna of the region, the largest (11 taxa) is the group of intentionally introduced mammals (N. procyonides, P. lotor, N. vison, S. vulgaris, O. zibethicus, C. pygagrus, C. nippon, C. elaphus, D. dama, B. b. bonasus, B. grunneins). It includes Asian (N. procyonides, C. aureus, C. nippon, C. pygagrus, B. grunneins, S. vulgaris), European (C. elaphus, D. dama, B. b. bonasus) and North American (M. vison, P. lotor, O. zibethicus) species. There are five species in the self-dispersing group: P. kuhlii, C. aureus, C. familiaris, C. capreolus, R. norvegicus.
From the list of invasive species of the European Union [List of Invasive Species in Europe], 4 taxa live in the study region: gray rat, sika deer, raccoon dog, raccoon. Of the 10 species of mammals included in the list of the 100 most dangerous invasive species of Russia, 6 species were noted in the region, of 53 alien species of mammals of the Russian Federation.
Distribution of alien mammals in the region
In the central part of the North Caucasus, certain alien invasive species of mammals (jackal, raccoon dog, sika, non-native subspecies of red deer, fallow deer, European bison, stray dog, etc.) are found everywhere, including in the territories of protected areas, which causes particular concern. The distribution of half of the alien taxa in the region is fragmented; 31% is widespread, and 21% is local. Their share in the regional fauna is significant (about 20%).
The widest range of altitudinal zones in the region is inhabited by the jackal (from steppes to subalpine); common squirrel – forests and forest plantations up to the subalpine zone inclusive; gray rat – residential landscapes up to 1600 m above sea level m. 10 alien taxa are confined to the lowland and foothill landscapes of the region (steppe zone, forest-steppe, and deciduous forest altitudinal zones), and only one taxa (yak) is confined to the mid-mountain and high-mountain landscapes (subalpine and alpine zones).
Classification of alien mammals
Alien mammals in the region are divided into synanthropes and alien mammals that invade local ecosystems. The first group includes only the gray rat, which enters the natural ecosystems of the region only in the plains and in the summer. Therefore, its impact is expressed only in anthropogenically transformed biotopes. In the second group (alien mammals that invade native ecosystems), based on the nature and strength of their impact on the ecosystems of the region, we can distinguish:
- alien taxa that have a negative impact on vegetation and soil cover (domestic);
- alien taxa that enter into competitive relationships with the local fauna (American mink, sika deer, jackal, raccoon, raccoon dog, as well as non-native subspecies of red deer);
- taxa whose negative impact on the natural ecosystems of the region is insignificant or uncertain, and they do not compete with native species (Mediterranean pipistrelle, common squirrel, muskrat, plains bison).
Based on the number in the region, the impact on the environment and native fauna (and not only on mammals, but also on birds, amphibians, and reptiles), the greatest negative impact is exerted by the sika deer, non-native subspecies of red deer, domestic yak, jackal, American mink, raccoon dog, raccoon. We can expect an increase in the number of these species in the region and their development of new territories.
Conclusions
In conclusion, the following should also be noted. The root cause of the current situation with introduced taxa in the North Caucasus is the lack of a unified approach to environmental issues and game breeding on the part of the Ministry of Natural Resources of the constituent entities of the Russian Federation. There are nine administrative units on the territory of the North Caucasus: two krais (Krasnodar and Stavropol) and seven republics (Adygea, Karachay-Cherkessia, Kabardino-Balkaria, North Ossetia-Alania, Ingushetia, the Chechen Republic, and Dagestan). Completely independent decisions are made in each subject, not interconnected with neighboring subjects. Far from a scientific point of view, decisions are made on the “restoration,” including “reintroduction,” of the hunting fauna of the region.
In addition to these subjects of the Russian Federation, one should also consider Rostov Oblast, which is partly included in the territory of the North Caucasus. Still, most importantly, it is adjacent to other subjects and has no physical and geographical barriers to the penetration of alien species in the case of their self-dispersal or accidental introduction. The second reason (no less important) is the adoption of decisions on environmental issues and issues of game breeding without discussion with the scientific community, whose opinion is extremely necessary to take into account. The third reason is the lack of a publicly available information base in the North Caucasus on the current state of biodiversity and large, including hunting, animal species.
Practical recommendations
- Conducting targeted monitoring and molecular genetics (for example, for sika, red deer, roe deer, etc.) studies to create an inventory of invasive species of the North Caucasus.
- Introducing changes to the relevant legislative acts at the federal level to prevent the importation of alien taxa, including subspecies.
- Creation of a unified expert group for the region, consisting of scientists, to make decisions on environmental issues and issues of breeding animals for hunting.
- Development and adoption of specialized measures aimed at significantly limiting the number of each invasive species up to their complete elimination.
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Journal reference
Tembotova, F. A., & Emkuzheva, M. M. (2023). Alien Mammals in the Ecosystems of the Central Part of the North Caucasus. Russian Journal of Biological Invasions, 14(3), 417-436. https://doi.org/10.1134/S2075111723030189
