南太行贮食鼠类对栓皮栎林隙和林下更新的影响

Recent studies have demonstrated the higher likelihood of regeneration in forest gaps compared with the closed canopy forest of Quercus variabilis and other Quercus plants. Not only lighting conditions limit its understory regeneration, but also seed dispersal, germination, and seedling establishment may be more important. However, we have little knowledge of the effect of scatter hoarding behavior of rodents on seed dispersal and seed fates in gaps and closed canopy forest. Moreover, it remains unclear how seed disperses to canopy gap and establishes successfully. Therefore, we, based on the interaction mechanism between food hoarding animals and Q. variabilis acorns and seedlings, plan to trace the seed dispersal patterns of Q. variabilis, seed bank and seedling dynamics in gaps and closed canopy forest by using infrared camera, coded plastic tags, and RFID tags to answer the following scientific questions: 1)What are the differences in probability of seed arrival, seed spatial distribution, and seed survival rate mediated by scatter hoarding rodents between gaps and closed canopy forest; 2) How food hoarding of animals affect seed bank dynamics in gaps and closed canopy forest, and whether there are different predation preferences; 3) How the cotyledon removal and shoot clipping affect the seedling regeneration of Q. variabilis between gaps and closed canopy forest. Our project is expected to uncover the response mechanism of Q. variabilis regeneration in gaps and closed canopy forest to scatter hoarding behavior of rodents, and further reveal the plant-animal interactions, then provide guidances for forest regeneration with artificial methods.

栎类树种多存在林隙实生更新优于林下的现象，限制其林下更新的因素不仅仅是光照条件，种子扩散、萌发和定植限制可能更重要。然而，与实生更新密切关联的林鼠贮食行为对林隙和林下种子扩散及其命运的影响机制尚不明确，种子传播到林隙成功定植的机制也有待阐明。本项目以南太行贮食鼠类与栓皮栎种子及幼苗间的关系为主线，以鼠类介导的种子扩散为切入点，运用红外相机监测、塑料标签标记及RFID 跟踪技术，探究林隙干扰下栓皮栎种子扩散过程，追踪种子库和幼苗库动态，从而揭示：1）鼠类介导的种子扩散传播到林隙和林下的几率、空间分布及存活率有何差异；2）鼠类对林隙和林下种子库动态有何影响，是否存在不同的捕食偏好；3）鼠类子叶捕食和茎部剪切对栓皮栎幼苗补充有何影响。通过上述研究，有望在理论上阐明贮食鼠类对栓皮栎林隙和林下更新的影响机制，进一步揭示森林更新过程中动植物间的相互关系；在实践上，为人工促进栎类次生林天然更新提供依据。

栎类树种多存在林窗实生更新优于林下的现象，限制其林下更新的因素不仅仅是光照条件，种子扩散、萌发和定植限制可能更重要。然而，与实生更新密切关联的林鼠贮食行为对林窗和林下种子扩散及其命运的影响机制尚不明确，种子传播到林窗成功定植的机制也有待阐明。本项目以太行山贮食鼠类与栓皮栎种子及幼苗间的关系为主线，以鼠类介导的种子扩散为切入点，运用红外相机监测、单枚种子标记跟踪技术，探究林窗干扰下栓皮栎种子扩散过程，追踪种子库和幼苗库动态，研究发现：1）岩松鼠和大林姬鼠是太行山栓皮栎种子的主要捕食者和扩散者，猪獾对栓皮栎种子大量捕食间接影响了鼠类介导的种子扩散成功率；2）森林生态系统中的择伐及林窗形成会改变食种子动物群落的组成及种子扩散能力，并在短期内改变植物的更新。林窗对动物搬运种子速率有显著影响，种子被搬运速率在CCF（郁闭林）显著高于林窗；3）啮齿动物在不同生境中的捕食和贮藏策略存在显著差异，栓皮栎种子通常在郁闭林下和林缘中被动物取食。相比之下，林窗中橡子更可能被分散贮藏；4）与郁闭林和林缘区相比，林窗中栓皮栎橡子的扩散距离明显增加；5）分散贮藏的橡子比例随林窗大小的增加未显著增加；6）在更大空间尺度上，林窗可能与海拔和坡位等环境因子共同作用对啮齿动物群落组成、数量及其扩散种子的能力产生关键影响。尽管如此，在小规模栎林植被恢复实践中，小林窗可能更有利于啮齿动物介导的种子扩散，可有效加速森林恢复和演替进程。通过上述研究，阐明了贮食鼠类对栓皮栎林隙和林下更新的影响机制，进一步揭示了森林更新过程中动植物间的相互关系；在实践上，为人工促进栎类次生林天然更新提供科学依据。