| Abstrakt: |
The fen orchid Liparis loeselii (L.) Rich. is one of the most endangered orchids of European wetlands and is listed in the Habitat Directive. In its range L. loeselii occupies different wetland habitats with fluctuating water level. A successful conservation of L. loeselii is based on the availability and conservation of suitable habitats. Therefore, it is important to understand the impact of ongoing changes in habitat environmental conditions on L. loeselii. The aim of the study was to find out the effect of environmental factors on chlorophyll a fluorescence of fen orchid L. loeselii in EU protected habitat 7210* Calcareous fens with Cladium mariscus and species of the Caricion davallianae near Lake Engure in Latvia. Such environmental factors as vegetation cover, impact of zoogenic factor, temperature, precipitation, and habitat water-level fluctuations were examined. The field study was carried out in 2015 and 2016. For the clarification of the influence of environmental factors on L. loeselii as a non-destructive method, chlorophyll a fluorescence (maximum quantum efficiency of PSII—Fv/Fm) was used. The Fv/Fm parameter was significantly higher in 2016 than in 2015. However, statistical analysis did not show any correlation between dynamics of Fv/Fm parameter during 2015 or 2016 and changes in habitat water level, temperature, or sum of precipitation. It could be influenced by a significant decrease in the number of C. mariscus generative shoots and a significantly higher sum of precipitation, which affected habitat water-level difference between years. In addition, water-level fluctuations were different between years. In 2015, in corresponding time when Fv/Fm parameter measurements were obtained, the water level in the habitat fluctuated within 8 cm while in 2016 within 5 cm in range. This study showed that the chlorophyll a fluorescence (Fv/Fm parameter) of L. loeselii in European Union priority protected habitat 7210* Calcareous fens with Cladium mariscus and species of the Caricion davallianae was not affected by single dominant environmental factor. Fv/Fm parameter of L. loeselii is influenced by vegetation cover and habitat water level. Favourable conditions for growth of L. loeselii are provided by balanced water supply. [ABSTRACT FROM AUTHOR] |
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