Vegetation factors influencing the establishment and growth of the endangered Japanese orchid, Cypripedium macranthos var. rebunense

Abstract

AbstractCypripedium macranthos var. rebunense is a well‐known endangered terrestrial orchid that is endemic to the cool‐temperate Rebun Island off the coast of northwestern Hokkaido, Japan. The present study aimed to identify suitable methods for conservation of this orchid through management of the natural vegetation. We analyzed the vegetation types and plants growing sympatrically with this orchid using two‐way indicator species analysis (TWINSPAN) and detrended correspondence analysis (DCA) ordination. Reproductive orchids can survive in various broad‐leaved and short to medium‐height herbaceous meadows with high plant species richness at a small scale in coastal regions. In order to maintain C. macranthos var. rebunense populations, succession to dense and tall large‐leaved herbs, Sasa scrub, shrubs, and trees, should be suppressed. Favorable vegetation for the establishment of seedlings of this orchid includes narrow‐leaved, medium‐sized grasses, sedges, herbs, mosses, and prostrate mat‐forming shrubs. The ground cover offered by these plants and their litter may favor stability of moisture, temperature, and suitable light conditions at the ground surface. In situ seed sowing at such ‘safe sites’ is a potential low‐impact technique to enhance seedling recruitment of this orchid.