Changes in the bryoflora of urban areas-a case study of Lesne Wzgorze in Szczecin (NW Poland)

摘要

Qualitative and quantitative changes in the bryoflora of forested hills called "Lesne Wzgorze" in the suburb of Szczecin (population 460 000) during the past 100 years are analysed. They concern a striking reduction in species diversity, changes in species composition and the frequency of particular species. A list of mosses and liverworts found on "Lesne Wzgoize" is provided. The phenomenon of the impoverishment of bryophyte communities in close proximity to large cities or industrial complexes hasoften been presented in the biyoiogical literature in the past thirty years. Reference has been made especially to a gradual decrease in the number of species and a general decline, resulting in the complete elimination of some species from city centres(Gilbert 1971; Jedrzejko 1975; Rao 1982; Seaward 1979; Wittig 1991). The data so far reported give cause for alarm. For instance, in Amsterdam, 23 species have become totally extinct since 1900 (Rao 1982); likewise, in West Berlin since 1787, 136 specieshave become extinct and 63% of the present-day bryoflora is considered to be endangered (Schaepe 1986).