Suburban zoos with large area exhibit landscape heterogeniety and structure. Zoo in Bratislava, the capital of the Slovak republik, is used as a case. It was established in 1960 as a suburban zoo at western marginal part of the city, in the lower part of the valey of Vydrica brook, called Mlynská dolina. It belongs to warm regional district of Slovakia. Biotopes and phytocoenological relevés were recorded in free areas out of the enclosures. Secondary landscape structure was characterized by natural, semi-natural and anthropogenic biotopes. Mesophilous oak-hornbeam forests, mesophilous grasslands and ruderal plant communities were recognized and characterized. Trampled plant communities (Lolietum perennis, Poetum annuae), non-trampled ruderal communities (Hordeetum murini, Conyzo-Cynodontetum dactyloni) and high-stem ruderal fringal communities (Urtico-Parietarietum offi cinalis, Pteridium aquilinum community, Chaerophylletum aromatici, Impaties parvifl ora community) were recorded and documented in Tables. Regional biodiversity centre is located in the high part of the zoo area with oak-hornbeam forest stands (Carici pilosae-Carpinetum). The role of zoos in native biodiversity conservation and spread of alien species is discussed. Zoos could be considered and managed also as habitats of non-native (alien) plants. The adaptive management of zoos is expected.