Department of Biology, Faculty of Science, Shinshu University, 3-1-1 Asahi, Matsumoto, 390-8621, Japan.
J Plant Res. 2010 Nov;123(6):741-9. doi: 10.1007/s10265-010-0318-5. Epub 2010 Feb 25.
We investigated the effects of roads on alpine and subalpine plant species distribution along an altitudinal gradient on Mount Norikura (3026 m a.s.l.), Japan. We examined the vegetation of herb and tree species shorter than 1.3 m along roadsides and adjacent natural vegetation at 200 m intervals between 1600 and 3000 m a.s.l. The timberline was at 2500 m a.s.l. Although the canopy opening was greater at the roadsides than in the natural vegetation, it was similar above the timberline. Soil cover and litter depth of the soil surface were less at roadsides than the natural vegetation, and gravel and rock cover were greater at roadsides. Species composition changed in similar directions from natural vegetation to roadsides along the altitudinal gradient. This direction was related to canopy opening and litter depth. Liliaceae, Ericaceae and Pinaceae were dominant families in the natural vegetation, and Asteraceae and Poaceae were greatest at the roadsides. Roadside plants were mostly herb species, while tree species increased in natural vegetation. Five exotic species were also observed at the roadsides. Sunny plant species gradually increased with altitude in the natural vegetation, indicated by the increase in canopy opening. By contrast, roadside plants were mostly sunny plant species irrespective of altitude. The number of lowland and montane species increased at the roadsides in the subalpine zone. Thus, roads strongly altered species composition of the natural vegetation along the altitudinal gradient probably because of changes in light and soil-surface conditions for growth and seedling establishment.
我们调查了道路对日本枪岳（3026 米海拔）沿海拔梯度的高山和亚高山植物物种分布的影响。我们检查了路边和自然植被中 1.3 米以下草本和木本植物物种的植被，间隔 200 米，海拔在 1600 到 3000 米之间。林线在 2500 米海拔处。虽然路边的树冠开口大于自然植被，但在林线以上则相似。路边的土壤覆盖和土壤表面的枯枝落叶层比自然植被少，而砾石和岩石覆盖则较多。物种组成沿海拔梯度从自然植被到路边以相似的方向变化。这种方向与树冠开口和枯枝落叶层有关。在自然植被中，百合科、石楠科和松科是优势科，而在路边，菊科和禾本科最多。路边植物主要是草本植物，而在自然植被中，木本植物则增多。在路边还观察到了 5 种外来物种。在自然植被中，阳性植物的物种随着海拔的升高而逐渐增加，这反映在树冠开口的增加上。相比之下，路边植物大多是阳性植物，与海拔无关。在亚高山带，路边的低地和山地物种数量增加。因此，道路强烈改变了自然植被沿海拔梯度的物种组成，这可能是由于光照和土壤表面条件的变化，影响了植物的生长和幼苗的建立。
