Autor: Vadim E. Panov, P. V. Bolshagin, I. V. Telesh
Rok vydání: 2001
Předmět:
Zdroj: Doklady Biological Sciences. 377:157-159
ISSN: 0012-4966
DOI: 10.1023/a:1019278212086
Popis: Structural transformations and modifications in the aquatic ecosystems’ functioning are usually related to human activity. Invasions or introductions of nonindigenous species of aquatic animals and plants to new habitats often cause these ecosystem alterations. During recent decades, some alien species have been rapidly and successfully invading new water bodies and start to play a substantial role in the recipient communities [1, 2]. Therefore, there is a necessity of quantitative estimation of the impact of alien species on the aquatic ecosystems for predicting possible changes in their ecological state. In this study, we used the results of a case study of predatory Ponto-Caspian cladoceran Cercopagis ( Cercopagis ) pengoi (Ostroumov, 1891), which has formed a permanent population in the eastern Gulf of Finland (EGF) since 1995 [3], to propose a method of quantitative estimation of the invader’s impact on the native plankton community. The calculation algorithm was elaborated using modern knowledge on ecosystem impacts of nonindigenous species [4] and basic principles of ecological physiology and production hydrobiology [5‐8]. Research methods and results of our study of the C. pengoi population dynamics and distribution, as well as zooplankton community structure, seasonal and interannual dynamics of the density, biomass and production rate in the EGF in 1996 through 1998 were published in a series of papers and summarized earlier [9]. The average population density of C. pengoi in the EGF during the study period varied between 82 and 219 animals per m 3 , which made up 1‐24% of the total zooplankton biomass. These crustaceans were present in plankton from late June through mid-October. Population density of C. pengoi peaked twice during the vegetation season (Fig. 1): at water temperatures 18‐ 19.5 ° C (July and August) and at 12.5‐14 ° C (September). Zooplankton in the studied area was taxonomically diverse and abundant, which is typical of mesotrophic water bodies [10]. Copepods Eurytemora affinis (Poppe), Eudiaptomus gracilis (Sars), Mesocyclops leuckarti Claus, and Thermocyclops oithonoides Sars formed the basis of the community, contributing ca. 50% to the total biomass. Besides, high abundance of cladocerans Bosmina longirostris (O.F. Muller), B. crassicornis P.E. Muller, Daphnia cristata Sars and rotifers Keratella cochlearis (Gosse), K. c. baltica (Sokolova), Keratella quadrata (Muller), and Synchaeta spp. was detected during the peak population densities of C. pengoi.
Databáze: OpenAIRE
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