啮齿动物对秦岭松栎混交林建群种种子扩散格局的影响

森林群落中的啮齿动物对林木种子存在着一定的取食偏好性,这种偏好性会使啮齿动物形成不同的捕食和贮藏策略,从而导致林木种子形成不同的扩散格局。以秦岭中段松栎混交林建群种锐齿槲栎、油松、华山松为研究对象,采用塑料标签标记种子方法,研究啮齿动物对种子传播和扩散格局的影响。结果表明:(1)种子特征是影响啮齿动物对其进行扩散的重要因子,油松种子以其质量小、种皮薄等特点吸引啮齿动物大量捕食,其原地取食率达到83.33%,显著高于华山松和锐齿槲栎种子。(2)锐齿槲栎和华山松种子大部分被搬运一定距离后再被取食和埋藏,其中,扩散距离在1 m以内、1—3 m和5—8 m的锐齿槲栎种子分别占59.12%、18.23%和13.26%,最远扩散距离达12 m处;华山松种子扩散距离主要介于在1—3 m(37.85%)和3—5 m(23.73%),在距离5—8 m(13.56%)、8—10 m(11.86%)和大于10 m(11.30%)区间也有一定的分布,最大扩散距离为12 m。(3)啮齿动物倾向于将锐齿槲栎种子搬运至松林内取食,而将华山松种子搬运至栎林内埋藏,说明不同林分类型及其环境因素对林木种子扩散后的分布格局具有重要影响。(4)3种类型种子被啮齿动物捕食的比例以油松最大(96.90%),锐齿槲栎次之(73.57%),华山松最小(50%);次年调查时,未被捕食的种子大部分已经被取食,仅有极少数锐齿槲栎种子萌发成幼苗(1.67%)。啮齿动物的捕食和贮藏行为对林木种子扩散及其成功更新都至关重要。

Effects of rodents on seed dispersal patterns of constructive species in the pine-oak mixed forests of the Qinling Mountains, Shaanxi Province, China

Rodents in forest communities have a feeding preference for tree seeds. This preference will lead to different predation and storage strategies for rodents, resulting in different diffusion patterns of tree seeds. In this study, the seed fate of Quercus aliena var. acuteserrata, Pinus armandii, and Pinus tabuliformis was studied to analyze the seed dispersal patterns of constructive species in the pine-oak mixed forests of the Qinling Mountains, Shaanxi Province, China. The results demonstrated that seed traits are the main factor affecting their removal by rodents. The in-situ seed predation rate of P. tabuliformis seeds was 83.33%, which was notably higher than that of other seed types, indicating that rodents preferentially fed on the small P. tabuliformis seeds. Q. aliena var. acuteserrata seeds and P. armandii seeds were transported to distant locations for feeding and burying. The Q. aliena var. acuteserrata seeds with diffusion distances of less than 1 m, 1-3 m and 5-8 m accounted for 59.12%, 18.23%, and 13.26% of predated seeds, respectively; the farthest diffusion distance was 12 m. The seed diffusion distance of P. armandii was mainly between 1-3 m (37.85%) and 3-5 m (23.73%), and was within the range of 5-8 m (13.56%), 8-10 m (11.86%), and greater than 10 m (11.30%);the maximum diffusion distance of P. armandii seeds was also 12 m. Rodents tended to transport Q. aliena var. acuteserrata seeds to the pine forest for feeding, while transporting the seeds of P. armandii to the oak forest, indicating that different forest types are an important factor in seed dispersal. P. tabuliformis seeds were the most predated on by rodents (96.90%), followed by Q. aliena var. acuteserrata seeds (73.57%), and P. armandii seeds (50%). In the following year''s survey, most of the predated seeds had been consumed, and only a handful of Q. aliena var. acuteserrata seeds had sprouted into seedlings (1.67%). Rodent predation and storage behaviors are critical for the spread of forest seeds and their successful renewal.