On the Problem of Steppe Ecosystem Conservation in the Central Caucasus

0 View
Key words: the Caucasus, steppe ecosystems, Arik Ridge, nature reserve.

 The steppe biomes of Russia are endangered, and remaining steppe ecosystems have degraded to differ-ent extents under the impact of human activities. The main destructive factor is extensive agriculture, which cannot be profitable without expansion to new areas. The Caucasus as a whole and particularly the Northern Caucasus, one of the most densely populated regions of Russia with an economic system based primarily on agriculture, are not an exception.

Natural steppe ecosystems in the Northern Cauca-sus occupied western and central Ciscaucasia within Krasnodar and Stavropol regions, the Adygei and Kab-ardino-Balkar republics, and North Ossetia, giving way to semidesert ecosystems in plain and foothill areas lying farther east. Although the natural range of steppe cenoses in the region is limited and exposed to signifi-cant anthropogenic impact, there is not a single nature reserve established in order to conserve the steppe eco-systems of the Northern Caucasus. Piedmont forests are the main protected biomes in the Caucasian, Teberda, and North Ossetia nature reserves; subalpine and alpine meadows, in the Kabardino-Balkar High Mountain Reserve. In the Dagestan Reserve, which consists of two separate areas, attention is focused on the conser-vation of desert landscapes and coastal ecosystems of the Caspian Sea region. The necessity of establishing a forest–steppe nature reserve was substantiated by spe-cialists of Stavropol State University in 2000 (Godzevich et al., 2000).

Although the flora and fauna of the Northern Cauca-sus are unique among mountain regions of Russia, the total size of specially protected natural areas (SPNAs) in the region is the smallest, and the pattern of their dis-tribution (in clusters) does not comply with the require-ment for representativeness of the protected biota (Tishkov and Belonovskaya, 2004). Among measures to conserve steppe ecosystems in the Kabardino-Balkar Republic, of primary importance is the establishment of a nature reserve as the most effective type of SPNAs with regard to protection of ecosystems and their com-ponents. Basic criteria for identifying areas of nature-conser-vation significance are the systems of parameters char-acterizing the state of botanical and zoological objects.

In the former case, these are parameters such as rarity of plant communities, their floristic and phytosociolog-ical significance, reduction of their ranges, and the risk of their extinction (Zhuravleva, 1999). In 2006, special-ists of the Institute of the Ecology of Mountain Areas surveyed steppe ecosystems made in Maiskii, Prokhlad-nenskii, and Terskii raions of the Kabardino-Balkar Republic. The results of this survey show that relatively small areas of virgin land on the Arik Ridge fully sat-isfy the above criteria. The fact that these areas still retain their natural steppe vegetation has also been noted by other authors (Kos, 1959; Kerefov and Fiap-shev, 1977; Shkhagapsoev and Volkovich, 2002). Physiographic characteristics.The Arik Ridge, located in the northwest of the republic (43°20′–43°50′N, 44°–45°E), is actually a system of spurs of the Terek Ridge with a subdued topography and elevations of no more than 450 m a.s.l. The watershed and slopes are composed of Pliocene sand–clay conglomerate rock masses. Prevailing soils are micellar, calcareous, ordi-nary chernozems with low or medium humus contents (Kerefov and Fiapshev, 1968). According to physio-graphic zoning of the Northern Caucasus (Chupakhin, 1974), this area is in the Kabarda sloping-plain region of the Mineralnye Vody–Terek district of the Stavropol–Terek province (Central Ciscaucasia). Its climate is moderately continental, with annual average temperature and precipitation of 11.0°C and 522.6 mm (according to meteorological data from the city of Terek between 1987 and 2002) (Ashabokov et al., 2005). The bulk of precipitation falls in summer but is largely lost by evaporation and surface runoff. The area has no natural sources of water and receives it from the irrigation system that includes the Malo-Kabardinskii, Akbashskii, and Tambovskii canals.

Phytocenotic and floristic diversity.According to florogenetic zoning of the Central Caucasus (Galushko, 1976), the Arik Ridge is in the Terek–Sunzha region of the Ciscaucasian district of the Kuban–Terek piedmont steppe province. According to the results of the 2006 survey, its natural vegetation is composed mainly by herb–grass, grass–legume–herb, grass–wormwood, herb–licorice, and, to a lesser extent, beard grass, feather grass, and shrub–herb phytocenoses. Among grasses, common are steppe species such asKoeleria cristata(L.) Pers., Phleum phleoides(L.) Karst., Poa angustifoliaL., Festuca valesiacaGaudin, Helictotri-chon pubescens(Huds.) Pilg., Bromopsis riparia (Rehm.) Holub., and Bothryochloa ischaemum(L.) Keng. The last species is dominant in places, forming local beard grass communities. Feather grasses (Stipa lessingianaTrin. et Rupr. and S. pennataL.) are rare, communities with their participation are small and have limited distribution. Stipa pennataL. is included in the Red Data Books of the Russian Federation and Stavropol krai (Krasnaya kniga…, 1998, 2002). How-ever, this species is not listed in the Red Data Book of the Kabardino-Balkar Republic (Krasnaya kniga…, 2000), probably because its distribution in the republic has not been studied sufficiently. According to Kos (1959), the vegetation of the Arik Ridge in the mid-20th century included one more feather grass species, Stipa pulcherrima(included in the Red Data Books of the Russian Federation, Kabardino-Balkar Republic, and Stavropol krai), but we have not found it on the slopes surveyed.

Ephemeral grasses such as Anisantha tectorum(L.) Nevski, A. sterilis(L.) Nevski, Bromus japonicus Thunb., and Poa bulbosaL. abundantly develop in spring. In trampled areas,Hordeum leporinumLink. is dominant.

Herbage is rich in species. The dominant group includes Salvia verticillataL.,S. tesquicolaKlok. et Pobed., Filipendula vulgaris Moench, Agrimonia eupatoriaL., Galium verticillatum Danth., Centaurea dealbataWilld., and Scabiosa ochroleucaL. Some communities also contain large proportions of Polygala anatolicaBoiss. et Heldr., Fragaria viridis (Duch.) Weston, Ajuga orientalisL., and Poterium polygamum Waldst. et Kit. Areas used as grazing grounds are often overgrown with Thymus marschallianusWilld. and the legume Onobrychis bobroviiGrosshm., which is hardly eaten by livestock because of abundant pubescence. An area of natural steppe vegetation with species rarely occurring in the republic and other red-list plants was discovered on the southwestern slope of the Arik Ridge 5 km east of the village having the same name (230 m a.s.l.). The floristic diversity of two communi-ties described there in a 10 ×10-m plot on May 25, 2006, reached 35 species in the herb–grass community and 39 species in the shrub–herb community. In both cases, the herbaceous layer had 85% coverage. The group of rare species consisted ofPaeonia tenuifoliaL., Asparagus verticillatusL. (another species of the genus,A. officinalisL., is more common), Dictamnus caucasicus(Fisch. et C.A. Mey) Grossh., Clematis lathyrifoliaBess. et Reichenb., Adonis flammeaJacq., Amygdalus nanaL., and some other plants.

The fern-leaved peony P. tenuifolia(Paeoniaceae) occurs in Prokhladnenskii raion of the republic, in typ-ical steppe habitats on the slopes of Dzhenali, Terek, and Arik ridges (Kos, 1959; Shkhagapsoev and Slonov, 1987; Krasnaya kniga…, 2000; our collections of 2006 from the Arik Ridge). The species is included in the Red Data Book of North Ossetia (Krasnaya kniga…, 1981), where it occurs along the Sunzha Ridge, and in the Red Data Books of the Russian Federation and Kab-ardino-Balkar Republic (Krasnaya kniga…, 1988, 2000). On the Arik Ridge, the average population den-sity of P. tenuifoliain the communities mentioned above is 7 ind./m 2 . In the same communities, single individuals of Bieberstein’s peony P. biebersteiniana Rupr. can be found. This species visually differs from P. tenuifoliain having broader leaf segments, and the dates of blooming and fruiting in these two species are also different. According to our observations, most P. tenuifoliaplants on May 16, 2006, already entered the stage of fruiting, while P. biebersteinianaplants were still blooming. It should be noted, however, that the taxonomic status of the latter species is ambiguous, since some botanists regard it as a subspecies of P. tenuifolia. In any case, it is listed as a true species in the Red Data Book of Stavropol Krai (Krasnaya kniga…, 2002).

Shrub communities consist mainly of Amygdalus nanaL. accompanied by Frangula alnusMill. and Rhamnus pallasiiFisch. et C.A. Mey. Communities described above contain no endemic species. Similar communities probably grow also on the Terek and Sunzha ridges but are absent in other regions of the republic. On this basis, such communi-ties may be classified as rare. The fauna of the region is poorly studied, and reli-able information on its present-day species diversity is almost absent. According to available data, large mam-mals are represented by the red fox and jackal. The ornithofauna includes the steppe eagle and small birds of prey; little bustard; among gallinaceous birds, quail; among passerines, the bee-eater Merops apiaster, which nests on ravine slopes.

Thus, the Arik Ridge is exposed to considerable anthropogenic impact: the major part of land is plowed, and most of the remaining part is under uncontrolled grazing load. In addition, population decline in some plant species (e.g., P. teniofoliaand feather grasses) is also explained by their commercial harvesting for dec-orative purposes. These factors are responsible for deg-radation of primary phytocenoses, expansion of weeds. and destruction of habitats favored by different species of the local fauna.

Thus, to conserve the steppe cenoses of the Central Caucasus within the Kabardino-Balkar republic, it is necessary (1) to establish a steppe nature reserve up to 10 000 ha in area on the Arik Ridge and (2) to include vascular plant species such as Stipa pennata, S. lessin-giana, Asparagus verticillatus, and Amygdalus nanain the Red Data Book of the republic.

The establishment of such a reserve will provide a basis for measures to restore populations of the little and great bustards, unique species of typical steppe ornithofauna that had been widespread in steppe eco-systems, including those of the Northern Caucasus.

In the mid-20th century, the little bustards used to nest on the Arik Ridge (A.N. Kudaktin, personal communi-cation) and the great bustard was recorded during the periods of flight and local winter migrations in the Cen-tral Caucasus (Beme, 1958).