AIMS: Vegetation distributions of alpine meadows are changing in response to natural environments. In Japan, several alpine meadows are distributed in low-altitude mountains; however, determining factors of the vegetation distribution of the low-lying alpine meadows are not fully understood. Therefore, in this study, I investigated not only natural environments but also human activities and explored their association with vegetation distributions of the low-lying alpine meadows.
LOCATIONS: Rebun Island, northern Japan.
METHODS: The distribution of alpine meadows and their species compositions were investigated by a combination of satellite images and field surveys. As for natural conditions, topography, geology, temperature, precipitation, humidity, wind strength and direction, and duration of sunshine were analyzed based on field measurements and meteorological data. The effects of human activity, including land management and nature preservation, were examined through literature documentation and interview surveys.
RESULTS: Overall, alpine meadows were developed on the southwest- and west- sides of the terrain with the prevailing southwestern wind. The habitat types were classified as follows: mountain summits above treeline, steep sea cliffs and hill summits below treeline. Their species compositions depended on habitat types and coastal plants were found on several study sites. The impacts of human activities on the vegetation were estimated to be small because of the terrains and the distance from trails.
MAIN CONCLUSIONS: The results suggest that natural environments, especially wind direction and topographic variation, play important roles in the distributions of alpine meadows. Statistical analyses are required to reveal each quantitative impact and the interactions with other environmental factors. Further research that combines measuring and mapping soil salinity and wind observation would help to explain the habitat types of coastal plants in alpine meadows.
Mots clés : vegetation|alpine meadows|Rebun Island|natural enveironment|human activity
A103561WT