Nature Conservation Research: Заповедная наука (May 2017)
Status of Calypso bulbosa and Cypripedium calceolus (Orchidaceae) populations in the Pinega State Nature Reserve
Abstract
Population-based studies on Calypso bulbosa and Cypripedium calceolus in the Pinega State Nature Reserve (Arkhangelsk region, Russia) and adjacent areas have been carried out. Since 1997, the monitoring of populations has been conducted on 34 established plots (17 for each species). Studies have been carried out directly within the Pinega Reserve area (Sotka river valley) and in the Reserve's buffer zone (slopes of the karst logs). Different trends of abundance dynamics in Calypso bulbosa and Cypripedium calceolus populations were identified. From 2002 to 2016, a significant decrease in the C. bulbosa individuals' number was registered. In 2006 this declining stabilised at low level. The total individuals' number within the established plots has decreased from 530 (in 2001) to 184 (in 2016). This reduction in abundance of C. bulbosa individuals is caused by changes in climatic parameters over the study period: the increasing of temperatures in July and August together with frequent dry periods. Climatic changes have led to a change in the coenoses' structure, a change of dominants in low forest layers, and an increase in the projective cover of the herb-shrub layer. Apparently, these changes have caused the declining of the C. bulbosa individuals' abundance in conditions of special protection regime. Cypripedium calceolus individuals' abundance has increased from 1231 to 2504 plants on the established plots over the study period. The increase of the August temperature is one of the main reasons for this phenomenon. There was a positive correlation (r = 0.6) between the average August temperature of previous year and Cypripedium calceolus individuals' abundance at present.
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