间伐对鼠类扩散林木种子的影响

Effects of Thinning on Seed Dispersal by Rodents in Secondary Forest

间伐作为一种林业生产活动,将会对区域内的植物群落和动物种群及行为产生影响.为了解间伐对鼠类介导的种子扩散的影响,2012年4月在王屋山区选择未间伐和间伐林地作为样地,标记、释放山杏(Prunus armeniaca)种子,调查鼠类对种子扩散的影响.研究表明:1)未间伐区鼠类的捕获率为6.7%,间伐区为2.7%;2)间伐区乔木密度降低56.3%、灌丛密度降低72.7%;3)未间伐区种子的扩散速率(半存留时间2 d)显著快于间伐区(半存留时间10 d);4)未间伐区,鼠类对种子的埋藏深度为(4.3±0.1)cm,间伐区为(3.9±0.2)cm,二者差异显著;5)未间伐区,鼠类对种子的多次扩散率为20.3%,间伐区为4.4%,二者差异显著.结果显示,林木间伐导致林区生境和鼠类种群显著变化,造成鼠类贮食行为和种子命运发生改变,最终将影响林区的幼苗更新.

As a common management strategy in forestry production,thinning could have a significant impact and interference on phytocoenosium and forest animals,and subsequently affect animal-mediated seed dispersal and forest regeneration. To understand the potential influence of thinning on the process of rodent-mediated seed dispersal,a study was conducted in April 2012. Seeds of Prunus armeniaca were marked and tracked in un-thinning and thinning forest in Mt. Wangwu area. The results showed that： 1）the relative density of rodent population drastically reduced from 6. 7% in un-thinning forest to 2. 7% in thinning forest; 2） the density of tree and shrub in thinning forest decreases from 56. 3% to 72. 7%; 3）seed dispersal rate in un-thinning forest（ half survival time： 2 days） was significantly higher than in thinning forest（ half survival time： 10 days）; 4） the difference of burying depth between un-thinning forest（ 4. 3 ± 0. 1） cm and thinning forest（ 3. 9 ± 0. 2） cm was significant; 5） more scatter-hoarded seeds were retrieved and buried again in un-thinning forest（ 20. 3%） than in thinning forest（ 4. 4%）. These results suggested that thinning have inevitable influence on plant community structure and the seed dispersal behavior of rodents,and finally affect the seed fate and seedling recruitment.