relative neighbour effect

 

Growth responses of different alpine plant communities to warming  (from Kudo 2010)

The growth of canopy-forming plants responded to the OTC treatment more rapidly in the lower fellfield community (F1) dominated by deciduous shrubs near to the timberline than in the upper fellfield community (F2) dominated by evergreen dwarf shrubs on a ridge. The difference in species composition may be a major factor contributing to the site-specific responses. Furthermore, responses to the OTC treatment were more apparent in the fellfield communities than in the snowbed communities.

The effects of warming on plant growth and vegetation structure were studied in two fellfield and two snowbed communities in northern Japan over 7 years using open-top-chambers (OTCs). OTCs increased the temperature by 1.1–1.8 °C, but the effects on snowmelt time and soil moisture were small. Vegetation height and canopy volume increased substantially at both fellfield sites as a result of the use of OTCs. Deciduous shrubs increased substantially at the lower fellfield and graminoids increased at the upper fellfield. In contrast, the responses of snowbed plants to OTCs were not significant. Because snowbed plants are covered by snow until mid summer, climatic amelioration during the snow-free period may influence plant growth only slightly if the snow-free period does not change.