Some ways to wildlife research in a megalopolis (on the example of the city of Nizhny Novgorod)

02018


Introduction
The process of urbanization is rapidly developing: more than 50% of the world's population already lives in cities occupying less than 3% of the earth's surface [1].Modern cities are the object of comprehensive research by many specialists [2][3][4][5][6][7][8].Scientists identify specific features of the urban habitat for both flora and fauna [9].Much attention is paid to the study and protection of urban biodiversity [10,11], however, urban ecosystems as habitats for rare wildlife species have not been sufficiently studied.In the Russian scientific literature, much attention is paid to rare plant species growing in cities [12][13][14][15][16][17][18][19][20][21], the results of an inventory of rare wildlife species in urban protected areas (PA) are presented [22][23][24], or the distribution and abundance of rare species of separate taxonomic or ecological groups are surveyed [25][26][27][28][29][30][31].Our goals were to discover rare wildlife species listed in the Red Data Books of Russia [32] and the Nizhny Novgorod Oblast [33,34] in the territory of Nizhny Novgorod and identify particular areas, which these species inhabit.Nizhny Novgorod is a megalopolis located in the geographical center of European Russia at the confluence of the Volga and the Oka, its area within the administrative boundaries is 46,000 hectares, the population is about 1.2 million people.

Materials and methods
The information for our analysis was the results of the authors' surveys carried out on the territory of the City of Nizhny Novgorod in 1984-2023, published records of rare species in the city, stock information (since the end of the XIX century), as well as data from citizen science [35] about rare wildlife species, listed in the Red Data Book of Russia and the Nizhny Novgorod Oblast, which were encountered on the territory of the city of Nizhny Novgorod.Lost habitats of rare species (known due to old records) and all the registrations of rare species recognized as accidental were excluded from the census.A database has been compiled containing 938 units of information about the records of 119 rare wildlife species in the city.A point GIS-theme "Registrations of rare wildlife species on the territory of the city of Nizhny Novgorod" has been developed.
Based on these data, we have identified 37 areas that are the most important as habitats for rare wildlife species.While identifying these areas, we took note of the presence or absence of protected areas on them.Thus, we have developed a polygonal GIS-theme "The most important natural areas as habitats for rare wildlife species in the city of Nizhny Novgorod".Lists of rare species have been compiled for each identified area, and its significance for these species is shown.
We tried to estimate the degree of legal protection of urban habitats of rare wildlife species and developed the special matrix presented in Table 1.
Table 1.The matrix to estimate the degree of legal protection of urban habitats of rare wildlife species.

Results
The list of 37 identified areas is presented in Table 2, the number of rare species on them is shown in Table 3. Locations of rare species records within the city, which were used to analyze and identify the most important habitats, are shown in Figure 1; locations of important habitats of rare species (with area numbers similar to those in Table 2) and their ratio to urban protected areas -in Figure 2.   1 and 2).Thus, 16 out of the identified important habitats already have got the status of protected areas (with a total area of 8,777.7 hectares), 21 (with a total area of 8,945.1 hectares) are not provided with legal protection.

Discussion
The composition of rare species in the city of Nizhny Novgorod is characterized with high taxonomic diversity.The number of rare species of different taxonomic groups is shown in Fig. 3.The largest number of rare species in the city belongs to vascular plants (37), insects (36) and birds (26).The significant majority of 119 rare species inhabiting the city of Nizhny Novgorod, are listed only in the regional Red Data Book [27,28], and 9 species are also listed in the Red Data Book of Russia [26].
We have discovered 88% out of 938 registrations of rare wildlife species were within 37 identified natural areas (Table 2).The results of estimating the degree of legal protection of urban habitats of rare wildlife species are presented in Table 4. Today, considering the degree of legal protection of urban habitats we can declare a third (32.77%) of the urban rare wildlife species are as safe as possible, while the habitats of a slightly larger number of species (35.29%) are not legally protected at all.We evaluate the existing level of protection of rare species urban habitats as insufficient.It is necessary to provide legal protection for all 37 areas important for the conservation of urban biodiversity.In this case, more than two thirds of rare species will be under comprehensive territorial protection, and for almost 11% more species protection will reach a high level.Only 8.4% of the species will remain without any legal protection.Out of these 10 species four (Vespertilio murinus L., Athene noctua Scop., Delichon urbicum L., Sphinx ligustri L.) are synanthropic, 5 species inhabit large rivers (Oka and Volga) and one is Meloe proscarabaeus Pz. being insufficiently studied and difficult to identify, which was found the only time outside the large natural urban areas.Such a projected level of protection of urban habitats can be considered as satisfactory.

Conclusion
As a result of the analysis, we discovered the territory of the city of Nizhny Novgorod being inhabited by 119 rare wildlife species.The database developed by us contains 938 units of information about records of these species in the urban ecosystem of the city of Nizhny Novgorod.
The analysis of maps allowed us to identify 37 areas on the territory of the city -the most important habitats of rare wildlife species, the human transformation of which should be avoided or requires special attention to the conservation of rare wildlife species and their habitats.
A total of 16 areas out of the identified habitats already have the status of protected areas (with a total area of 8,777.7 hectares), 21 (with a total area of 8,945.1 hectares) are not protected.Today, the habitats of a third of rare species are not protected by law.
If all 37 identified natural areas are adopted as protected, more than 82% of rare urban species will be provided with territorial protection in full or at a high level.

Fig. 1 .
Fig. 1.Records of rare wildlife species of within the territory of the city of Nizhny Novgorod, used to identify the most important habitats of them.

Fig. 2 .
Fig. 2.Locations of important habitats of rare wildlife species within the territory of the city of Nizhny Novgorod and their overlapping with established protected areas (area numbers are similar to those shown in the Table1 and 2).

Fig. 3 .
Fig. 3. Taxonomic structure of rare species registered in the city of Nizhny Novgorod (%).

Table 2 .
Nature areas within the territory of the city of Nizhny Novgorod, recognized as the most important habitats of rare wildlife species listed in the Red Data Book of Russia and the Nizhny Novgorod Oblast.

Table 3 .
Number of rare wildlife species listed in the Red Data Book of Russia and Nizhny Novgorod Oblast that are registered in nature areas being the most important habitats on the territory of the city of Nizhny Novgorod (Numbers of areas are similar to those shown in the Table2).

Table 4 .
The degree of legal protection of urban habitats of rare species.