Contribution to the characteristic of Cladium mariscus (L.) Pohl population in the initial zone of floating mat on an oligo-humotrophic lake in north-eastern Poland

Anna Namura-Ochalska

doi:10.5586/asbp.2005.022

Abstract

In the initial phase of growth in an oligo-humotrophic lake, <em>Cladium mariscus</em> forms a dense and tall sawgrass bed invading the open water in the form of a floating mat. High densities of submerged evergreen perennial stems of <em>C. mariscus</em>, over two metres high and abundantly fruiting, ensure its persistence, and form a natural barrier to the invasion of other species. Dense mats of sawgrass are formed as a result of clonal and rhizome growth. Although diaspore production is abundant under natural conditions, only vegetative propagation of stems was observed. In different variants of the experiment only seeds wintering on stems of mother plants were capable of germinating. Hard seed coats had an important effect on the germination capacity of seeds.

Highlights

Cladium mariscus (L.) Pohl, which in Poland has the eastern boundary of its continuous range, belongs to the group of old amphiancylusian relicts (Czubiñski 1950)
A deep concern arises from the fact that both the number of C. mariscus sites and the size of the area occupied by this species are rapidly declining, especially in recent years (Borowiec 1990; Jasnowska and Jasnowski 1991; ̄ukowski and Jackowiak 1995; Buczek and Buczek 1993, 1996)
The typical physiognomy of this community was due to the highly dominant characteristic species C. mariscus that reached a coverage of the 5th degree of the Braun-Blanquet scale, and a height of more than 2 m

Summary

Introduction

Cladium mariscus (L.) Pohl, which in Poland has the eastern boundary of its continuous range, belongs to the group of old amphiancylusian relicts (Czubiñski 1950). In Poland, it occurs mainly in the Pomeranian Lakeland (Jasnowski and Jankowska 1960; Jasnowski 1962; Kêpczyñski and Ceynowa 1968; Jasnowski et al 1972), Wielkopolska region (Kaczmarek 1963; Denisiuk 1980; ̄ukowski and Jackowiak 1995), and in the Lublin region (Fija3kowski 1961; Buczek and Buczek 1993, 1996). Not so often and on fewer sites this species can be observed in north-eastern Poland, that is, in the Masurian Lakeland (Polakowski 1963, 1969; Soliñska 1965; K3osowski and Tomaszewicz 1979; K3osowski 1986-1987, 1990). A deep concern arises from the fact that both the number of C. mariscus sites and the size of the area occupied by this species are rapidly declining, especially in recent years (Borowiec 1990; Jasnowska and Jasnowski 1991; ̄ukowski and Jackowiak 1995; Buczek and Buczek 1993, 1996). Its occurrence is limited to wet and marshy habitats, recently subjected to deep transformations, most often irreversible

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