Definition of sections of the Exclusion Zone with the highest index of biological diversity as an indicator of ecological balance and radioecological stability

Client: State Agency of Ukraine of the Exclusion Zone Administration (SAEZ)

Due to the considerable extent of the Exclusion Zone, the works in 2011 were focused only on the assessment of individual sites in the north, in the east andin the north-west of the region. Mostly, the works were focused on the study of the fauna of bats, which are fully included to the Red Book of Ukraine (http://www.menr.gov.ua/cgi-bin/go?node=RedBook), and represent nearly a quarter of all Red Book animals that live in the Exclusion Zone. The works included: 1) catching of animals for species identification, banding, and a general description (animals were released at the catching sites), 2) recording of vocalization by means of ultrasonic detector and digital recorder with the following analysis of the vote to determine the species; 3) description of the general natural conditions at the experienced areas. In addition, collection of information on the diversity of landscapes was done, natural values ​​of the complexes and the presence of rare species of animals and plants were measured. The works were carried out with participation of Kharkiv Karasin National University specialists.

In 2013, the relevant activities were continued and extended to a new site within EZ, which has the operating name “Horodyshche” (5115 hectares) and is located in the vicinity of Nova Krasnytsia, Richytsia, Stari Shepelychi, Buriakivka villages.

The works included the following activity types:

• general description of radioecological conditions;
• general description of landscape and soil conditions;
• description of plant systems;
• description of vertebrate fauna;
• search for Red Data Book species of plants and animals, other valuable natural objects, evaluation the role of the research site in their life;
• assessment of biodiversity figures within the research sites;
• assessment of the relative level of anthropogenic transformation within the local systems and the level of modern anthropogenic impact;
• general assessment of the need for assigning a conservation category to the research site and identification of the relevant territorial boundaries.

Based on the research results and with due regard to the fact that practically all quarters within “Horodyshche” site are located outside the zones of industrial or forestry interests, we made a conclusion that the entire territory of “Horodyshche” research site, with the total area of ​​5115 hectares, is worth a status of regionally-important nature reserve, with “reserved” land-use conditions.

The detailed report on the research results was delivered to the customer.

In 2014 the works were extended to a new ChEZ site bearing the operating name “Budniansko-Richytsky Luky” (5,870 hectares) and located between the former population centers including Krasne, Buda, Tovsty Les, Nova Krasnytsia, Richytsia any Rudky.

The activities included the following types:

• general description of radioecology conditions;
• general description of landscape and soil conditions;
• description of plant systems;
• description of vertebrate fauna;
• search for Red Data Book animal and plant species, other valuable natural objects, assessing the role of the test site in their life;
• estimation of biodiversity figures on the research sites;
• estimation of the relative level of anthropogenic transformation within the local systems and the level of modern anthropogenic impact;
• general assessment of the need for assigning a conservation category to the research site and determination of appropriate territorial borders.

Based on the research results and with due regard to the fact that practically all quarters on the site named “Budniansko-Richytsky Luky” are located outside any industrial or forestry interest zones, we made the conclusion that the entire territory of the research site named “Budniansko-Richytsky Luky” with the total area of ​​5870 hectares worth a status of regionally-important nature reserve, with “reserved” conditions of land use.

The detailed report on the research results was handed to the Customer.

In 2015, the relevant works were conducted in the two main directions:

• Automatic collection of photographic data on the diversity of species and characteristics of large birds and mammals distribution within three areas in ChEZ, which were far removed from each other and had different ecological and radiation conditions.
• Comparative analysis of the biodiversity indexes and conservation value of the ChEZ areas subjected to studies in 2012-2014.

Results of the studies demonstrated that all experimental areas, i.e. “Novoselki”, “Tolstyi Les”, “Budnyansk and Rechytsa Meadows”, and “Horodyshche”, were natural territorial complexes typical of Kyiv Polissya. However, they were notable for their outstanding abundance of rare or unique landscape, plant, and animal components.

The two sites, including “Novoselki” and “Tolstyi Les”, are characterized by a several-fold increased (if compared to the entire ChEZ) percentage of timber stands that are over 100 years old, including those growing under the edaphic conditions of fertile soils with normal and high hydration level (subclusters, sudubravas, clusters, oak forests).

If compared to the above areas, lands of the area named “Budnyansk and Rechytsa Meadows” were subject to higher anthropogenic transformation, and at the time of the accident those were agricultural lands (pastures, hayfields, fields). However, typical local conditions contributing to the increase of biodiversity and return of rare plants and animals to the ecosystems started their recovery there resulting from long-term reservogenic succession.

In all the areas, vertebrate fauna is typical of Polissia. Mammals including predators (wolf, lynx, raccoon dog, marten, otter, badger), ungulates (moose deer, wild boar, roe deer, red deer, Przhevalski’s horse), bats (common and lesser noctule, rabbit, seabat-pygmy, forest bat, water bat, particoloured bat), rodents (squirrel, beaver) and others are equally common (though their quantities are different).

Bird fauna in the research areas also demonstrates a high conservation value.

Unaffected conditions of biogeocoenoses have not survived in the areas that are discussed in the report. Their total area is mostly represented by the lands subjected to total cutting, artificially managed pine plantations, amelioration, drainage, cattle grazing, and cultivation of crops before the Chernobyl accident. However, their semi-natural conditions have been mostly preserved, which contributed to a gradual recovery of their autochthonous complexes. Most sites are characterized by low level of human impact; the only exception is “Novoselki”, where timber felling is in progress thus naturally jeopardizing natural systems existing there. Generally, value of the areas was practically assured. The economic activities currently existing in the exclusion zone should be improved, conservation status of the territory should be updated, i.e. withdrawn into a full reserve of national level, in order to maintain the trends, which are favourable for preservation and development of plant and animal populations.

The detailed report on the research results was submitted to the Customer.

The objectives of research activities in 2016 were:

• Automatic collection of photographic information on species diversity and macrofauna distribution characteristics within the three separate sites in ChEZ having different environmental and radiation conditions (final stage of the work that was started in 2014);
• Analysis of the obtained photographic data;
• Assessemnt of macrofauna diversity on the three test sites with regard to their ecological and radiation conditions;
• Identification of the criteria useful for searching the areas in ChEZ having a significant environmental value.

Three sites, 5 km in radius each, were used for the research. The first site is located in the northeast of ChEZ around the village of Krasne; the second one is 20 km west of the Chornobyl NPP around the village of Tovstyi Lis; and the third site is located between the villages of Zamoshnia, Korogod and Novosilky. The first site has a high level of radioactive contamination; the second one has the average level; and the third site has low contamination level.

Ltl Acorn 6210MC cameras were used in the investigation. The camera traps were installed on each of the three sites, 14 ones per a site. Taking into account the size of the area and in order to cover as much of it as possible, every 6-12 weeks the cameras were moved to new points within a site. In 2014-2016, the cameras were moved 10 times in total; and the total number of their location points was 288.

We analyzed dependency between the animals registration frequency and characteristics of a camera trap location point, namely: radiation conditions (contamination of the area with ¹³⁷Cs and ⁹⁰Sr, exposure dose rate), relative level of human impact, presence of a population center, water bodies, movement canalization factor, level of shrub stratum and plant stand development, type of landscape (forest, forest skirt, woodland, meadow), principal species of trees, age of forest, level of edaphotopes humidity (hygrothop), level of edaphotopes abundance (trophotop). The analysis was performed with due regard for the seasonal changes that occur in the diet, behavior, and redistribution of animals and for 12 animal species that surely could be registered by the camera traps placed on dry lands: hares (genus), Przewalski’s horse, wild boar, red deer, European roe deer, elk, lynx, raccoon dog, wolf, fox, martens (genus), badger.

The research data demonstrated that the distribution and redistribution of animals depend on their biological needs and traits, characteristics of their habitats and seasonal changes in the ecology of each species.

Despite the significant differences in both radioecological and natural characteristics, the composition of species and the frequency of animals registration (being a relative abundance indicator) were not fundamentally different for the three sites. The differences in species composition are first and foremost attributed to the species that are generally rare within ChEZ and/or are locally abundant (bison, bear, Przewalski’s horse); and secondly to the species that could be accidentally detected by the camera traps that were adjusted for large terrestrial mammals (aquatic mammals: otter, mink, beaver and wood mammals: sciurus, marten, birds).

Totally, 18 mammal species and 51 bird species were registered during 2014-2016; including 5 “Red Book” species of mammals (brown bear, river otter, bison, Przewalski’s horse, lynx) and 10 ones of birds (white-backed woodpecker, gray crane, black stork, golden eagle, white-tailed eagle,  hazel grouse, spotted eagle, great gray owl, grey shrike, black grouse). The bear, bison and golden eagle were registered for the first time due to the camera traps.

The detection of localization points of rare animals is of great importance from the viewpoint of ensuring nature conservation activities, though it cannot guarantee detection of same species in other similar conditions.

Territorial distribution of animals depends on their habitat characteristics, biological needs and on each species characteristics, seasonal changes in the biology of animals and their forage base. Within each site, there are usually the localities with a higher and lower frequency of animal registration. Seasonal changes in the placement of such localities were observed for some species (deer, wild boar, Przewalski’s horse, badger); and for another ones, even changes in the preference to forest and plant conditions have not caused significant changes in their spatial distribution (hare, elk, roedeer, lynx, fox).

Continuous forests with large areas, especially “clean” pine forests and lands with dry and worse edaphic conditions, are the factors of macro fauna biodiversity reduction. Their registration frequency tends to increase in edaphotopes with moderate moist (fresh, wet) and moderate fertility of soils (mesooligotrophic, mesotrophic); although in some seasons a significant increase of the marker occurs in moist oligotrophic conditions and in damp edaphotopes. Nevertheless, since such conditions are typical of most ChEZ areas, we can state a fairly even spatial distribution of most animal species within ChEZ. Even higher diversity of species and abundance of animals can be expected in meadow edaphotopes that border on the forest ones of higher trophication. There are not very many such sites in ChEZ, especially when it comes to large areas.

In view of the above, the sites worthy of their conservation value assessment are as follows:

• between the villages of Richytsia, Stari Shepelychi, Novi Shepelychi;
• around the village of Buriakivka;
• between the villages of Varovychi and Buda-Varovychi;
• between the villages of Novyi Myr, Stara Rudnia, Vesniane;
• southwards of the villages of Illintsi and Rudnia-Illinetska;
• in the proximity of Novosilky village;
• between the villages of Cherevach and Zalissia;
• between the villages of Chapaivka and Kryva Gora;
• between the villages of Usiv, Masheve and Krasne;
• eastwards of Paryshiv, Ladyzhychi villages.

Therefore, ChEZ most likely has a relatively even territorial distribution of biodiversity indexes in the representatives of land-based macro fauna; with the general tendency towards reduction deep in large forest areas and drier areas, and towards increasing along forest edges and in relatively rich and humidified edaphotopes. The local diversity of edaphic conditions and landscape elements contributes to the diversity and abundance of animals; and this is especially evident in the cases when animals are prone to seasonal changes in their habitats.

A detailed report on the research results was submitted to the Customer.

In 2018 the activities were expanded onto the left bank of the Prypiat River within the ChEZ. The work significance has enhanced by the creation of the Chornobyl Radiation and Ecological Biosphere Reserve in 2016, as the development and implementation of the Reserve’s environmental measures depend on the knowledge of the quality of the lands, the status of populations and the spread of rare species, the understanding of problems that exist on specific areas and the understanding of the role played by certain areas in the conservation and enrichment of biodiversity.

The submitted report includes the following sections:

• “Radioecological conditions”;
• “Landscape and soil conditions”;
• “Plant complexes”;
• “Fauna of the vertebrates”;
• “Red Book species”;

“Relative level of anthropogenic transformation and present-day anthropogenic impact”.

In 2018 the main focus was given to an area with a working name “Paryshivska Pushcha” with a total area of 11 560 hectares, located in the southern part of the left bank outside the floodplain area.

Results of the research showed that the left bank of the ChEZ in general and “Paryshivska Pushcha” area in particular are typical natural-territorial complexes of the Kyiv Polissia, which for centuries undergone a significant anthropogenic transformation. During 1986-2018, due to the long-term reservatogenic succession that took place after the evacuation of people and a significant reduction of economic activity scales, the natural conditions inherent in this region began to reproduce here. These conditions contribute to the increase of biological diversity and the return of rare plants and animals to the biocenosis.

The specific feature of “Paryshivska Pushcha” area is the higher, in comparison with the entire ChEZ, percentage of forests growing on fertile soils. Some of these forests are at the age of 100-180 years and more, and therefore they have retained phytocomplexes that are not typical for younger woodlands. This area is also distinguished by a large number of different marshes with their specific phytocomplexes.

Actually, the reservation conditions which have been in place since 1986, contribute to the reproduction of many rare species and complexes. Six Red Book plants were found in “Paryshivska Pushcha” in 2018, while according to the literature data, up to another 38 species are possible here. In addition, the southern boundary of the distribution of regional rare plants of the Red Book species of the marsh complex, as well as plants that are included in the formation of species included in the Green Book of Ukraine, passes the territory of the ChEZ.

17 species of the Red Book mammals and 10 species of bats have been found within this area.

The fauna of birds also shows a high conservation value. Among 145 species found on the left bank, 125 are nesting. Among them there are 15 Red Book species. Another four Red Book species are present during seasonal migrations. There are also species that have a limited distribution in the region, because they are connected with rare biotopic conditions.

The conservation value of the left-bank lands is not in doubt. In order to maintain trends favourable for the conservation and development of plant and animal populations, it is necessary to strengthen the security regime of the considered area and continue its research.

A report based on the R&D works was submitted to the Client.

Contact:
Deputy Director General of IRL in science
Head of Radioecological Research Department
Gaschak Sergei Petrovich
Tel. +38 (04579) 6 15 62
Fax: +38 (04579) 6 15 62
e-mail: sgaschak@chornobyl.net