Affiliation: | Research Institute of Mechanics and Applied Mathematics, Department of Mathematical Modelling in Ecology and Economics, Rostov State University, Stachki St. 200/1, 344104 Rostov-on-Don, Russia;;Institut national agronomique Paris-Grignon, 75231 Paris cedex 05, France;and;Écologie des populations et communautés, Bât. 362, UniversitéParis-Sud XI, 91405 Orsay cedex, France |