覆网保护和埋藏对坚果树种种子直播的影响

作者以都江堰林区6种代表性坚果树种为对象,研究了覆网保护和埋藏等措施对直播种子存活和幼苗建成的影响,同时调查了鼠类在春秋两季的数量变化。结果表明:秋季鼠类对种子的捕食压力大,使得种子在无保护的情况下很少存活到出苗;而秋季覆网保护(第二年春季解除覆网)和完全保护(覆网一直保留到第二年10月调查时为止)均增加了直播种子的存活和出苗率;将种子埋藏在土壤1–4cm也显著增加直播种子的存活率和出苗率,这与鼠类密度(12%)在秋季显著高于春季(2%)有直接关系。此外,坚果树种的种子存活和出苗与其种子特征有一定联系。因此,作者认为如果根据鼠类数量的季节波动规律而采取适当育林措施(如保护和埋藏等)能够增加森林种子直播的效率。

Effects of enclosure protection and seed burial on direct seeding of nut-bearing trees

In a subtropical evergreen broad-leaved forest nearby Dujiangyan City, Sichuan Province, Southwest China, we investigated seedling establishment of six nut-bearing tree species with and without enclosure protection and seed burial, with the aim of determining the impact of these treatments on seed survival and seedling establishment. At the same time, we studied population dynamics of seed-eating rodents in the autumn and the following spring. The results showed that, without enclosure protection, most of the seeds were predated due to high predation pressure in the autumn. The emergence rate of seedlings of all the studied species significantly increased under autumn protection, complete protection, and 1-4 cm burial under soil covered by litter. Effects may reflect the seasonal dynamics of rodent abundance and the characteristics of the seeds. We conclude that taking effective measures such as enclosure protection and seed burial according to seasonal dynamics of rodent population would promote survival after direct seeding.