I. Zagorodniuk started his zoological research in ornithology when he was a student of Taras Shevchenko National University of Kyiv. His diploma project at University was devoted to the study of migrations and flying of birds,. Also, being a University student, I. Zagorodniuk started the study of amphibians, conducted the experiments on biotope association of the amphibian group Bombina bombina - Bombina variegata, and also conducted experiments on the energy of Bombina species in winter time and the influence of wintering on the age structure of this species populations. At the same time, I. Zagorodniuk started the study of karyotypes of amphibians and rodents. When he began his work at I. I. Schmalhausen Institute of Zoology, the subject of his research was shifted towards the study of rodents. The first publication on this subject was devoted to the karyotypic variability of Microtus arvalis The results of this research became the basis of justification of the species independence for Microtus arvalis — M. obscurus. This became one of the results of PhD research by I. Zagorodniuk and the subject of the most cited publication by the scientist.
Taxonomic investigations
Taxonomic investigations make up a significant part of the scientific work of I. Zagorodniuk. This investigations were shifted from a description of small taxa to the group analysis and the discovery of patterns of formation and existence of low and high levels of taxonomic diversity. In this investigation, considerable attention is given to the groups of evolutionary and morphologically close species, primarily rodents. As a result of this cycle of research, 8 new taxa were described and a significant number of taxonomic permutations were proposed. The following taxa are described as new to science:
Besides the taxa described for the first time, the researcher also substantiated the species, subfamily or generic statuses of a number of other taxa, which names were known as synonyms of other species or genera for a long period of time.
Sylvaemus uralensis — is currently recognized as a separate species that includes Apodemus microps.
Mus spicilegus Petenyi, 1882 — is currently recognized as a separate species that was a part of Mus musculus.
Microtus obscurus — is currently recognized as a separate species or a group of subspecies of the species Microtus arvalis.
Arvicola scherman — is currently recognized as a separate species or group of subspecies of the species Arvicola amphibius.
Sicista loriger — is currently recognized as a separate species or group of the subspecies of the species Sicista subtilis.
Sylvaemus Ognev, 1924 — is currently recognized as a separate genus or subgenus of the genus Apodemus.
Terricola Fatio, 1867, — is currently recognized as a separate genus or subgenus of the genus Microtus.
Alexandromys Ognev, 1914, — is currently recognized as a separate genus or subgenus of the genus Microtus.
In the publications by I. Zagorodniuk a number of specifications are proposed regarding the interpretation of ranks and scopes of superfamily groups of mammals and unified names of some other taxa.
I. V. Zagorodniuk is the initiator of the establishment and the founder of Theriological school — annual gathering of theriologists taking place in different regions of Ukraine since 1993.
Scientific publications
Scientific interests: fauna and ecology of terrestrial vertebrates of Eastern Europe, biogeography and evolution of cryptic species, species concept and models of speciation, rare species and adventitious biota. According to the personal profile of Igor Zagorodniuk at the h-index of his publications is equal h = 24. The most cited 10 works of Igor Zagorodniuk by this criterion are:
Zagorodnyuk I. V. Karyotypic variability and systematics of the Arvicolini. Communication 1. . Vestnik zoologii. 1990. Vol. 24. № 2. P. 26–37. = 54 cit.
Zagorodniuk I. V. . Series: Proceedings of the Theriological School. Vol. 5. Kyiv, 2002. 60 pp. = 53 cit.
Zagorodnyuk I. V., Boyeskorov G. G., Zykov A. E. . Vestnik Zoologii. 1989. № 4. P. 55–59. = 45 cit.
Zagorodniuk I. V. . Reports Natl. Acad. Sci. Ukr. 1999. № 5. P. 203–210. = 44 cit.
Zagorodniuk I. V., Fedorchenko O. O. . Vestnik zoologii. 1995. Vol. 29, № 5-6. — P. 49–58. = 42 cit.
Boeskorov G. G., Kartavtseva И. В., Zagorodniuk I. V., Belianin A. N., Liapunova E. A. Nucleolus organizer regions and B-chromosomes of field mice. Genetika. 1995. Т. 31. P. 185-192 = 41 cit.
Zagorodnyuk I. V. . Vestnik zoologii. 1991. Vol. 25, № 1. P. 36–45. = 40 cit.
Godlevska O., Parnikoza I., Rizun V., Fesenko H., Kutsokon Yu., Zagorodniuk I., Shevchenko M., Inozemtseva D. . The 2nd edition. Kyiv, 2010. 80 p. = 38 cit.
Zagorodniuk I. V. . Vestnik Zoologii. 1996. Vol. 30, № 1–2. — P. 28–45 = 44 cit.
