Palaeobiodiversity of Knyszyn Forest (NE Poland) Mires Based on the Late Glacial and Holocene Histories of Vascular Plant Species

Abstract

Peat and lacustrine sediments are a valuable source of knowledge about past biodiversity. Plant macrofossil remains were identified in sediments of mires in northeastern Poland’s Knyszyn Forest. Among them, the remains of species currently absent in this area, such as Potamogeton pusillus, P. friesii, P. filiformis, Myriophyllum alterniflorum, and Cladium mariscus, have been found. In addition, the history of Betula humilis and its possible correlations with another species of bush birch—Betula nana—were of interest. Radiocarbon dating allowed the presence of the studied species to be placed within a time frame, and it was thus established that aquatic species existed in the area under study during the Late Glacial and the turn of the Holocene. Cladium mariscus occurred during the Greenlandian and Meghalayan stages of the Holocene and then became intolerant of habitat changes that occurred. The coexistence of two species of birch known to exist since the Late Glacial was interrupted in the Northgrippian. B. nana, then disappeared from the area, and B. humilis continued to occur as it was more resistant to the changing environmental conditions. It must be emphasized, however, that these conclusions were made possible by the researchers’ access to undisturbed deposits. The mires present in the area of study remain in good condition, providing important and relevant materials for palaeoecological research.

Keywords

• mire
• peat
• plant macrofossil remains
• Late Glacial
• Holocene
• northeastern Poland