Specialized urban populations of birds: forms and mechanisms of the steadiness
in urban environment. 1. Urbanisation as the transition of species population
system in the condition of maximal steadiness in the unstable, changeable and
heterogeneous environment. - V.S. Friedmann, G.S. Eremkin, N.Yu. Zakharova-Kubareva.
- Berkut. 15 (1-2). 2006. - P. 1-54.
The present research deals with urbanization of wild bird and mammal species. Forms and mechanisms of population steadiness in the urban landscape have been examined. The urbanization process turned to be the directed change of population system forming de novo in the urbolandscape to the side of stable organization variants special for the given environment. The population organization of different types in urbolandscape is found to provide its stability in the conditions of directed and fast changes together with instability and heterogenic structure of habitats. It is shown that among different species settling in the urban environment one and the same type of population organization meets the corresponding demands. Its features are openness and flowage of the groups, far order of settlement levels and other units of population system, constant movements of the individuals between the groups as a respond to the signals of urbo-environment significant changes. The urban variant of population system organization turns to be completely opposite to the population structure of the same species in the non-urban habitats. After formation of the urban types by the species and successful developing of the town the urban population separates from the maternal local population and begins to exist independently in the urban landscape. The variety of adaptation aberrations in ecology, behavior and mode of life of urban birds is the population system stability function in the urban landscape and not the results of individual selection. It is shown that the urbanization process of the species goes firstly on the population level being the system structure transformation towards the most stable state in the town (city) territory developed by the species. Only after the appearance of stable urban population the urban individuals show the rapid growth of different changes in ecology, behavior, mode of life that was traditionally described by naturalists as species adaptation to the city conditions. The key features of urban population stability/instability are described. Their application to relative species allows us to distinguish potential urbanists from instable and vulnerable species that could be soon pushed out of the city. The application of corresponding criteria to the urban populations of relative species constituting one guild allows us to predict if their developing of the given town would be successful/unsuccessful. The latter is very important since in urbanized landscapes close species are ecologically indistinguishable as a rule. So one can not predict successful/unsuccessful urbanization taking into account the differences in the range of habitats, breeding success, and other external features. [Russian].
Key words: sinurbanization, population, metapopulation, steadiness, urban gradient.
Address: V.S. Friedmann, Laboratory of ecology and nature conservation, biological faculty, Moscow university, Leninskiye gory, 1/12, 119992 Moscow, Russia; e-mail: firstname.lastname@example.org.