生境对啮齿动物介导下锐齿槲栎种子命运的影响

Impact of habitats on rodent-mediated seed fates of Quercus aliena var. acuteserrata

干扰作为森林演替的驱动力,在改变森林结构和地表植被的同时也对林内动物介导下的种子扩散过程产生影响.本研究采用塑料标签标记法,选取秦岭林区不同人为干扰后形成的3种类型生境(未抚育林分、抚育3年后林分、裸地),研究啮齿动物扩散行为对不同生境类型锐齿槲栎种子命运的响应.结果表明:抚育3年后林分的种子扩散速率最大,裸地扩散速率最小.裸地的种子原地取食率显著低于未抚育(25.0%)和抚育3年后林分(36.3%),而抚育3年后林分的种子搬运后取食率显著高于未抚育林分(17.3%)和裸地(5.0%),且抚育3年后的林分中被啮齿动物分散埋藏的种子比例最高(4.3%).种子扩散距离以抚育3年后林分最大(26 m),且扩散距离显著大于裸地和未抚育林分.锐齿槲栎种子的初次扩散过程在不同生境中表现不同,其种子后期成苗率也存在差异.不同类型生境在一定程度上影响啮齿动物的觅食策略,最终导致不同的种子扩散模式和森林天然更新格局的形成.

Disturbance is the driving force of forest succession, which can change forest structure and surface vegetation. Disturbance also affects rodent-mediated seed dispersal. In this study, numbered plastic tags were used to examine the responses of rodent dispersal behavior to the fates of Quercus aliena var. acuteserrata acorns at three habitats formed by different artificial disturbances in pine-oak mixed forests in the Qinling Mountains, i.e., unlogged stand, stand in the third year after tending thinning, and bare land. The results showed that seed removal rate from stands in the third year after tending was significantly higher than that in the other two habitats. The proportion of predation in bare land was significantly lower than that in the unlogged stand(25.0%) and in the stand in the third year after tending thinning(36.3%). In the third year after tending thinning, the seed predation rate after seed moving was significantly higher than those in the unlogged stand(17.3%) and bare land(5.0%). Moreover, the proportion of scatter hoarding after removal was also highest in the stand in the third year after tending thinning(4.3%). The longest average dispersal distance(26 m) occurred in the stand in the third year after tending thinning, which was significantly longer than those at the other two habitats. Therefore, the different habitat types significantly influenced the initial seed dispersal process by rodents, with consequences on the rates of seedling establishment. Habitat types affected the foraging strategies of rodents, thereby leading to different seed dispersal modes and natural regeneration patterns in the forest.