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: wolf17@list.ru.
