1. Introduction

The purpose of the work is to track the dynamics of the occurrence of fauna representatives in the catches on the territory of the Central District of Kyzylkum in the period from 1991 to 2021. For the analysis, archival epizootological data of field studies were used on the territory of the Central District of the anti-plague department of the city of Zarafshan of the Republican Center for Plague Prevention of the Ministry of Health of the Republic of Uzbekistan and the anti-plague station of the medical and sanitary unit of the regional department "Uchkuduk" of the State Institution "NMMC Fund". The inspection of the Kyzylkum territory supervised by these institutions was carried out on the basis and in accordance with the annual Work Plans approved by the director of the Republican Plague Prevention Center of the Ministry of Health of the Republic of Uzbekistan.

The data presented for analysis are based on the results of a survey of the Central section of the Kyzylkum plague focus in 1991-2021, in the spring-summer and autumn-winter seasons, from 1.2 decades of March to 1 decade of June and from 2.3 decades of September to 2, 3rd decade of November.

The study of the material was carried out in accordance with the methods generally accepted in the anti-plague service.

For the entire analyzed period, based on the available data, 24 species of animals and birds of 5 species, 43937 specimens in total, ectoparasites - fleas 245197 specimens, ticks 20502 specimens were caught and studied [1-6]. The Modern landscape complexes of the Central Kyzylkum are a fragile and less stable formation, where intercomponent relationships are very weak and easily destroyed under the influence of external factors. This is due to the sharp contrast of environments and the peculiar specificity of natural conditions. At the present stage of development of the geosystems of the Central Kyzylkum, their transformation and dynamics are significantly influenced by two groups of factors: natural and anthropogenic. Natural development is formed as a result of the interaction and interdependence of numerous factors, such as geological, geomorphological, geoecological, hydrogeological, climatic, hydrological, soil, plant and zoogenic. Anthropogenic factors mainly include forms of organization of human economic activity: cutting down wood and shrubs for fuel, excessive grazing without taking into account the anthropogenic load on such fragile arid complexes, uncontrolled hunting, mining without subsequent reclamation of technogenic complexes. The region under study is the main center of not only grazing, but also the mining industry, under the influence of which mining landscapes arose. Among the latter, young, mature and old mining landscapes can be distinguished according to the time of occurrence.

2. Materials and Methods

These geocomplexes - waste heaps, wastelands, tailings, rock dumps, devoid of soil and vegetation cover, contribute to the intensification of the desertification process not only in the mining areas, but also in the nearby sandy landscapes [8].

In accordance with the scheme of epidemiological zoning of the Kyzylkum, the zone of its Central District, according to the type of economic development, is an interlacing of territories (zones) of livestock breeding, agricultural and livestock breeding and industrial livestock breeding [12].

Biocenotically, the territory of the Central District of the Kyzylkum corresponds to the Turan psammophilous community [7,12].

Animals exist in the conditions of certain landscapes, where the degree of favorable environment depends on many factors, among which abiotic (physical) factors play an important role. At present, the extremely negative impact on the composition of animal populations of global predictors is most clearly manifested - solar activity, the greenhouse effect, as a result, aridity, lowering of groundwater, etc [9].

The complexity of the impact of the above regulators is reflected in the qualitative and quantitative composition of the fauna of the Kyzylkum biocenoses.

For the period from 1991 to 2023, according to the cumulative results of field studies of the territories of the Central District of the Kyzylkum, it was established that the dominant in catches were rodents were the subfamily (family) of gerbils-Gerbillinae (94.28%), of which 71.04% were large gerbils- Rhombomys opimus (64.1% occurrence index), 18.1% Meriones meridianus (18.2% occurrence index) and 10.6% Meriones erythrourus (9.4% occurrence index). The genus of ground squirrels of the Sciuridae family in catches amounted to 3.3%, where the yellow ground squirrel - Citellus fulvus (84.04%) prevailed, the occurrence index was 4.5%, the remaining 15.9% was the fine-toed ground squirrel - Spermophilopsis leptodactylus (occurrence index - 0.68%). The jerboa family - Dipodidae accounted for 0.76%, where 33.8% was the upland jerboa - Dipus sagitta (occurrence index - 0.45%), 32.9% - small jerboa - Allactaga elater (occurrence index - 0.4%) , 16.9% - comb-toed jerboa-Paradipus ctenodactylus (occurrence index - 0.12%), 12.7% - Severtsov's jerboa - Allactaga severtzovi (occurrence index - 0.3%) and 2.06% - jerboa sp-Jaculus turkmenicus sp (occurrence index - 0.15%), other species of jerboas - Allactaga bobrinskii et Jaculus turkmenicus, amounted to 0.89% and 0.59% each (occurrence index - 0.1 and 0.09%), respectively. It should be noted the percentage ratio in the captures of the brownie-Mus musculus mouse with an occurrence index of 1.63%, which is associated with the specialization of the tactics of surveying settlements by anti-plague institutions. Among the birds (occurrence index - 11.7%) in catches, the dancer's Wheatear (Oenantha isabellina) dominated - 73.5% (occurrence index - 0.13%).

Diagram 1

Diagram 2 and 3. Percentage composition of predominance in catches of rodent species of the families of gerbils and jerboas

Diagram 4. Dynamics of occurrence of the subfamily Gerbillinae

Indicators of trends-vectors of development, relative in terms of values, of the cumulative results of captures in the territory of the Central District of Kyzylkum, based on the quantitative composition of gerbils in catches, indicate a prolongation of the dynamics of a decrease in the occurrence of Rhombomys opimus due to an increasing (replacing in nature and total in terms of impact) dynamics on the part of gerbils species Meriones meridianus and Meriones erythrourus.

For the indicated 30-year period of field research on collections of ectoparasites from the sectors of the geographical region of the Central District of Kyzyl Kum under the supervision of anti-plague institutions, fleas in total amounted to 99.2%, ticks - 7.7%.

The quantitative dominant in the flea landscape in absolute terms is the genus Xenopsylla (74.1%), where the proportion of the gerbilli species is 79% (occurrence index - 47.8%), the hirtipes species - 14% (occurrence index - 12.1%), species conformis-6.5% (index of occurrence-7.1%) and species conformis dipodis represented by 0.23% (index of occurrence-0.35%); the genus Coptopsylla in catches was noted in 11.4% and is represented by species lamellifer-78.2% (occurrence index-11.8%), olgae-10.1% (occurrence index-4%), as well as species trispinus-7.9% (occurrence index-2.4%) and bairamaliensis-3.6% (occurrence index-0.9%); the subgenus Nosopsyllus makes up 11.07%, and predominantly, in terms of indicators, is represented by the species tersus-44.4% (index of occurrence-3.8%), laeviceps-32.8% (index of occurrence-3.9%), turkmenicus- 22.5% (index of occurrence - 5%) and species fidus - 0.06% (index of occurrence - 0.56%);

Diagram 5. Aggregate data (%) on occurrence indices among fleas

Fleas of the genera were less expressed quantitatively in the collections: Paradoxopsylla (1.2%) is represented by teretiforons in 95.5% (index of occurrence - 3.9%) and repandus - 4.58% (index of occurrence - 0.32%); Stenoponia (0.56%), of which the most represented are vlasovi-75.6% (occurrence index-0.52%), conspekta-23.6% (occurrence index-0.32%), Stenoponia Stenoponia amounted to 0.65 % with an occurrence index of 0.18%; Synosternus (0.44%) amounted to 87.6% longispinus (index of occurrence - 1.5%) and pallidus - 12.3% (index of occurrence - 1.57%); Rhadinopsylla (0.31%) is represented in 62.6% of cedestis (occurrence index-0.66%) and teretiforons-37.3% (occurrence index-0.22%); and the genus Echidnophaga at 0.19% and represented by oschanini at 66.4% (occurrence index - 0.28%) and gallinacea - 33.5% with an occurrence index of 3.23. It should also be noted the occurrence in catches of fleas of the genus Сtenocephalides felis (2.1%) and Rostropsylla daca-0.74%.

Diagram 6. Distribution of the main genera of fleas by occurrence

Diagrams 7-9 are presented below to analyze the occurrence in catches of fleas of various species from among the most widespread genera and subgenera (Xenopsylla, Coptopsylla, Nosopsyllus).

Diagram 7. Dynamics of occurrence (in %) of fleas of the genus Xenopsylla

Chart 7 clearly shows (trend line) a year-on-year decrease in the proportion of the genus Xenopsylla hirtipes in flea catches and a dynamic increase in the content of the genera Xenopsylla gerbilli et conformis in collections.

Diagram 8. Dynamics of occurrence (in %) of fleas of the genus Coptopsylla

From the analysis of the occurrence vectors of species of fleas of the genus Coptopsylla, the dynamics of the annual total prevalence in catches of fleas of the genus Coptopsylla olgae et trispinus was clearly noted against the background of a gradual decrease in the trend in the occurrence of fleas of the genus Coptopsylla lamellifer.

Diagram 9. Dynamics of occurrence (in %) of fleas of the subgenus Nosopsyllus

This diagram characteristically emphasizes the increase in the dynamics of years in the occurrence of fleas of the species Nosopsyllus turkmenicus in catches and, similarly, in the dynamics of the decrease in the occurrence of fleas of the species Nosopsyllus laeviceps.

The genus Hyalomma of the family Ixodidae dominates among ticks in terms of distribution in the territory - 55.2%, after, in 29.9% of cases, the subfamily Gamazoidae was found in the collections of ticks, the genus Ixodes of the subfamily Ixodinae amounted to 9.62%, the genus Dermacentor of the family Ixodidae amounted to 6,1%, the genus Ornithodoros of the family Argasidae-5.6%, the genus Haemaphysalis of the family Ixodidae -5.4%, and the least common were ticks of the subgenus Boophilus of the genus Rhipicephalus of the family Ixodidae - 4.8% and, in fact, the genus Rhipicephalus-4.7%.

Diagram 10. ticks, occurrence, in %

Summarizing the presented data, we can conclude that the dominance in the collections according to the total index of occurrence in the collections of ticks of the Ixodidae family and less pronounced in total. during the analyzed period of time, the proportion of the presence of ticks of the subfamily Gamazoidae in the catches.

Diagram 11. Dynamics of occurrence (in %) of ticks on the territory of the Central District of Kyzylkum

This diagram clearly demonstrates the dynamic and pronounced dominance of ticks of the genus Hyalomma in the catches, a gradual increase in the share of the presence of ticks of the genera Ixodes and Ornithodoros and Haemaphysalis in the collections against the background of a clear decrease in the vector line of occurrence in the collections of ticks of representatives of the genus Gamazoidae. Also noteworthy are the data presented below on the frequency of occurrence of various types of fauna orders in the annual dynamics of the analyzed years and their qualitative composition in the quantitative spectrum of the studied years.

Diagram 12. Frequency of occurrence in catches of various species of rodents, predators, birds in the period 1991-2021

It follows from the diagram that the most common species in the chronology of years are representatives of the order Rodentia - by the predominance of quantitative accounting: subfamily Gerbillinae-Rhombomys opimus, Meriones meridianus, Meriones erythrourus, family Sciuridae-Citellus fulvus, Spermophilopsis leptodactylus, from the family Dipodidae-Dipus sagitta et Allactaga elater and Mus musculus.

Diagram 13. The frequency of occurrence in collections of ectoparasites of various types of fleas and ticks in the period 1991-2021

It follows from the present data that in the dynamics of the occurrence of a line of ectoparasites over a 30-year period until 2021 inclusive, they are most stably encountered, in descending order: from the Aphaniptera order, the genus Xenopsylla-Xenopsylla gerbilli, Xenopsylla conformis and Xenopsylla hirtipes; genus Coptopsylla-Coptopsylla lamellifer and Coptopsylla olgae; subgenus Nosopsyllus-Nosopsyllus tersus, Nosopsyllus turkmenicus and Nosopsyllus laeviceps; as well as fleas of the genus Echidnophaga oschanini, Stenoponia vlasovi and Rostropsylla daca, from among the subclass Acari representatives of the genus Hyalomma of the family Ixodidae, subfamily Gamazoidae dominate, less often - the genus Haemaphysalis of the family Ixodidae, the genus Ornithodoros of the family Argasidae and the genus Ixodes of the subfamily Ixodinae.

Diagram 14. The frequency of occurrence of animal and bird species, ectoparasites from the entire spectrum of the studied

3. Results and Discussions

From the assessment of these graphs, a clearly traceable trend of degradation of the prevalence of animal species and fleas within the surveyed area follows, starting from 2009-2010, when the number of species of captured rodents decreased to 9 species out of 29, on average, rodents Rhombomys opimus, Meriones meridianus, Meriones erythrourus, Citellus fulvus, Allactaga elater, Mus musculus and Cricetulus migratorius. It should be noted that representatives of the order of birds have not been found in catches since 2009. Among fleas, in this period, it decreased in collections to 11 species, on average, out of 34, among which Xenopsylla gerbilli, Xenopsylla conformis, Xenopsylla hirtipes, Coptopsylla lamellifer and Coptopsylla olgae, and Nosopsyllus laeviceps, Echidnophaga oschanini, Stenoponia vlasovi were noted for stable dynamics of occurrence.

4. Conclusions

In addition, taking into account the data on the increase in the proportion of some representatives of the order of ectoparasites, we can conclude that the most adaptive representatives, namely, fleas of the genera Xenopsylla gerbilli et hirtipes, Nosopsyllus turkmenicus et tersus, Coptopsylla olgae et trispinus; ticks of the genus Hyalomma, less Ixodes, Haemaphysalis, Ornithodoros.

The authors confirm that there is no conflict of financial/non-financial interests associated with writing the article.