Standortverhältnisse und Morphometrie von Geranium sanguineum L. auf der Combe Martigny im Walliser Rhônetal, Schweiz

Abstract

A significant larger stem height, internode number per stem, ramification number per stem, leaf-tip length, stem number/m 2 , leaf area indes/m 2 and stem number per individual plant (polycormon) of Geranium sanguineum have been observed in forbland of the Geranio-Trifolietum alpestris as compared with forest, woodland and grassland. We summarize this in the statement that Geranium sanguineum attains its maximum vitality in forb communities. The highest presence of G. sanguineum falls within the same formation according to the referred literature. The time consuming analysis of air and soil temperature, wind velocity and plant nutrient content within the soil did not bring in the expected decisive site factor(s) in the vegetation catena forest-forbland-grassland. According to earlier “holistic” field observations the lower vitality and lower presence of G. sanguineum in forest as compared with forbland may be caused by the light factor. The absence of G. sanguineum in the majority of the dry grasslands in the research area may be due to excessive drainage of the site or/and present or former mowing or grazing. The higher vitality of G. sanguineum within the forb communities has been observed in the forest bordering type. The decisive site factor is here, following D ierschke , the intermittent sunlight along the forest edge. Guidelines for the classification of the Geranio-Trifolietum alpestris (in Quercetea pubescentipetraeae, Trifolio-Geranietea or Festuco-Brometea) cannot be derived from the sampled microclimatic and edaphic parameters. The statements of both J akucs (1972) and D ierschke (1974) about this question turned out to be valid locally only.