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The aim of this diploma thesis was to elaborate a literature survey and especially to conduct an experimental study of ecological demands of the critically endangered species Sedum villosum. The localities, on which S. villosum formely occurred, disappeared largely because of habitat destruction by draining and plowing of wet meadows, or by the abandonment followed by development of high vegetation and biomass accumulation. Therefore, this work could contribute to the knowledge of shadow influence and surrounding vegetation concurency on seed germination and flowering of this species. Retrieved knowledge can be later used for rescue program realization (repatriation options, strengthening populations, habitat requirements). The experiments showed a significant negative effect of the shading and the presence of surrounding vegetation (sedges, brown mosses and peat mosses) on germination and flowering of S. villosum. Furthermore, it was found that S. villosum is able to germinate directly on water surface, with seed germination even higher than on wet soil. The experimental sowing, planting and subsequent monitoring of germination, growth and survival of S. villosum at the rehabilitated area of Knížecí Pláně (NP Šumava) showed that it is possible to strengthen S. villosum population by sowing and planting autochthonous material on prepared areas with a torn down turf. As an acceptable tools seems to be using mulch from mown in the area of the original population. Similar process can be used in the future for restoring historical localities of this species.

Moss dominated ecosystems are an important part of the global terrestrial carbon cycle. Over large areas, remote sensing can be useful to provide an improved understanding of these ecosystems. Two boreal mossess (Pleurozium and Sphagnum) were assessed using remote sensing based spectral vegetation indices for estimating biochemical capacity and photosynthetic efficiency by varying net photosynthesis rate via changes in water content. In the laboratory, changes in the normalized difference vegetation index (NDVI) and chlorophyll index coincided with declining photosynthetic capacity due to desiccation. This effect was more dramatic in Sphagnum. The photochemical reflectance index (PRI) did not vary with changes in CO2 supply as anticipated, possibly due to overriding effects of changing water content. The water band index (WBI) was strongly related to water content but this relationship showed an uncoupling in the field. Bi-directional reflectance measurements indicated what WBI was sensitive to sensor, sun, and moss surface slope angles. / xi, 110 leaves : ill. (some col.) ; 29 cm.