95 ISSN 2075-1117, Russian Journal of Biological Invasions, 2018, Vol. 9, No. 2, pp. 95–107. © Pleiades Publishing, Ltd., 2018. Original Russian Text © R.I. Burda, S.N. Koniakin, 2018, published in Rossiiskii Zhurnal Biologicheskikh Invazii, 2018, No. 1, pp. 2–17. Spontaneous Dispersion of Species of the Genus Juglans L. in the Forests and Parks of Kyiv R. I. Burda a, * and S. N. Koniakin a, ** a Institute for Evolutionary Ecology, National Academy of Sciences of Ukraine, Kyiv, 03143 Ukraine *e-mail: riburda@ukr.net **e-mail: ser681@ukr.net Received November 15, 2017 Abstract—In 2016–2017, in the forests and parks of Kyiv, 22 points of spontaneous spread of selfsown plants of six species of Juglans L., namely, J. ailantifolia Carrière, J. cinerea L., J. mandshurica Maxim., J. nigra L., J. regia L., and J. subcordiformis Dode (Juglandaceae DC. ex Perleb), were found. In eight locations, 919 self- sown individuals and 45 maternal trees of these species were examined. Local populations are left-side in most cases; they have different spatial and ontogenetic structures and some of them contain young reproduc- tive individuals. According to our data (abundance, size, and ontogenetic composition), the points of self- seeding spread are spontaneous self-reproducing populations. Schematic maps of distribution of Juglans spe- cies have been created. These results expand the concept of naturalization of representatives of the genus Jug- lans in urban forests and parks. The collected factual information and maps can serve as the basis for a strategy of monitoring the invasions of exotic trees. Keywords: Juglans, self-seeding, naturalization, self-reproducing population, invasive alien species, woody plants, Ukraine DOI: 10.1134/S2075111718020029 INTRODUCTION For cultivated woody groves in Kyiv, seven culti- vated species from the genus Juglans L. (Juglandaceae DC. ex Perleb) were indicated, which are fairly broadly cultivated in Eastern Europe and Ukraine, in particular (Sokolov, 1951; Lypa, 1952; Grishko-Bog- menko, 1974; Shchepot’ev et al., 1987; Zhigalova, 2007). According to morphological and molecular studies, they belong to three sections (Konechnaya, 2012; Mu et al., 2017). Section 1. Juglans: J. regia L. Section 2. Cardiocaryon Dode: J. ailantifolia Carrière (J. sieboldiana Мaxim., J. allardiana Dode), J. subcordi- formis Dode (J. coarctata Dode, J. lavallei Dode, J. cordi- formis Maxim.), J. mandshurica Maxim. (J. cathaiensis Dode , J. draconis Dode , J. callosa Dode, J. stenocarpa Maxim.), J. cinerea L. (J. oblonga Mill., J. cathartica Michx.). Section 3. Rhysocaryon Dode: J. nigra L. (J. pitteursii Morr., J. rugosa Dode, J. costata Dode), J. microcarpa Berland. (J. rupestris Endelm. ex Torr., J. subrupestris Dode, J. neomexicana Dode). On the basis of morphological and molecular characteristics of J. cinerea, some authors recognize Trachycaryon Dode as a separate section (Aradhya et al., 2007; Stone et al., 2009; Dong et al., 2017). J. californica S. Watson, J. hindsii Jeps. ex R.E. Sm., and J. major (Torr.) A. Heller are noted exclusively for botanical gardens and only for several forestries of Ukraine (Grishko-Bogmenko, 1974; Shchepot’ev et al., 1987; Zhigalova, 2007). All mentioned species of the genus Juglans have Holarctic origin. J. regia has three genetic centers, Chinese, Central Asian, and Near East. The primary ranges of the species J. ailantifolia, J. subcordiformis, and J. mandshurica belong to the Chinese–Japanese, and J. cinerea, J. nigra, and J. microcarpa belong to North American genetic center (Lypa, 1952; Zhu- kovskii, 1970; Aradhya et al., 2007). The tendency of Juglans species to secondary wild habits was noted in Ukraine repeatedly. According to Lypa (1952), in several arboretums (Bantyshevskii, Prelestnoe village, Slavyanskii district, Donetsk oblast; Trostyanetskii, Chernigov oblast) J. cinerea easily reproduces naturally under the cover of groves. On the basis of herbarium labels from the summer collection of the year 1999 from Kyiv, S.L. Zhigalova noted mass self-seeding in the Syretskaya Grove of J. mandshurica and of J. nigra (KW collection 063566) in Feofania (KW collection 063528). Spontaneous dispersal of J. regia and J. mandshurica in Kyiv was reported (Mosyakin and Yavorska, 2002). The latter two species were reported for habitats in villages (Burda, 2003). Most often, this meant dispersal of these species on specially protected territories in the Poles’e and Forest Steppe, including protected areas in Kyiv (Burda et al.,