坡向与海拔对青海省拉鸡山不同植被土壤种子库的影响

Effects of slope aspect and altitude on the soil seed bank under different vegetations in Laji Mountains of Qinghai Province, Northwest China

于2006年5和10月调查了青海省拉鸡山不同海拔（3100-3920 m）和坡向（阳坡、阴坡和山脊）土壤种子库，研究海拔和坡向对土壤种子库分布格局的影响。结果表明：春、秋季土壤种子库的物种生活型较接近,主要以多年生草本为主，1年生或2年生草本次之，落叶灌木很少出现。土壤样品中种子库储量、物种组成随海拔的增加，阳坡总体上呈下降趋势，阴坡亦具有趋同性，但阳坡波动较阴坡剧烈，山脊土壤种子库储量最小；土壤种子库在垂直方向有递减的规律，土壤样品中的种子主要分布在0-3 cm土层内，其次是3-6 cm，且随深度的增加土层中所含种子库储量呈逐渐递减趋势；土壤种子库储量大小具有季节动态，且10月份（种子雨结束后季节）大于5月份（种子萌发季节）。

In May （spring） and October （autumn）, 2006, an investigation was conducted on the soil seed bank at different altitudes （3100-3920 m） and slope aspects （sunny slope, shady slope, and ridge） in the Laji Mountain of Qinghai, aimed to study the effects of slope aspect and altitude on the distribution pattern of the soil seed bank. The species life forms in the soil seed bank were similar in spring and autumn, mainly dominated by perennial herbs, followed by annual herbs, and deciduous shrub rarely appeared. The storage and species composition of the soil seed bank increased with altitude and presented a decreasing trend on the sunny slope and shady slope, but had more obvious fluctuation on the sunny slope. The storage of the soil seed bank was the minimum on the ridge. The soil seed bank in vertical direction had a diminishing pattern. The seeds were mainly distributed in 0-3 cm soil layer, followed by in 3-6 cm soil layer, and decreased gradually with increasing soil depth. The storage of the soil seed bank had seasonal dynamics, being greater in October （seed-rain finished season） than in May （seed germination season）.