动物分散贮食行为对植物种群更新的影响

分散贮食是许多动物取食行为策略的重要组成部分。对以植物种子为主要贮食对象的动物来说,种子内营养物质含量、种子大小以及种子内次生化合物的含量等因素都直接影响动物的贮食行为。动物偏爱贮藏个体较大的种子,大种子多被搬运并分散贮藏在远离种源的地方,而小种子则多被就地取食,以补充动物贮食过程中的能量消耗。贮食动物主要通过空间记忆、特殊路线以及贮藏点周围的直接线索等途径重新获取贮藏点内食物。在重取过程中,一些贮藏点被遗忘,其中的种子成为植物种群更新的潜在种子库。因此,分散贮食动物不仅是种子捕食者,还是种子传播者,它们对植物种子的捕食、搬运和贮藏,影响了植物种子的存活和幼苗的建成,从而在一定程度上影响植物种群的更新、分布。植物种群为了促进种子的传播,在进化过程中逐渐形成了形式多样的适应性策略,降低种子的直接被捕食率,提高种子的被贮藏率。研究动物分散贮食行为对植物种群更新的影响,将有助于理解贮食动物与植物之间的互惠关系,从而认识贮食动物种群在生态系统中的作用,为生物多样性的保护提供科学依据。

Animal scatter-hoarding behavior and its impact on the regeneration of plant populations

Scatter-hoarding is one of the most important foraging strategies for many animals. For animals whose hoarding targets are seeds, the hoarding behavior is directly affected by many factors relevant to seeds, including their size, the nutrient content, and secondary metabolites inside the seeds. Animals prefer larger seeds that are delivered and scatter-hoarded somewhere far away from the food sources. Smaller seeds are eaten on the spot by animals in compensation for the energy consumed during the hoarding process. Hoarding animals retrieve the food at the cache sites mainly according to the following: spatial memory, particular paths, and direct clues around the cache sites. During the retrieval process, some cache sites are forgotten or missed by the hoarding animals, and these seeds become potential pools for the regeneration of some plant populations. Therefore, scatter-hoarding animals play two roles in ecological systems: they are not only consumers, but also circulators, of seeds. The serial behavior of scatter-hoarding animals (i.e., retrieval, delivery, and storage), directly influence both the survival of seeds and creation of seedlings. Furthermore, to some degree, the regeneration and distribution of certain plant populations are affected by the behavior of scatter-hoarding animals. As for plant populations, the most urgent mission is to protect their own seeds. In other words, in order to avoid being consumed and to decrease the forage rate by animals, the plant populations have gradually formed multiple and various adaptive strategies during the evolutionary process. Following a brief statement of conception and research background of hoarding behavior, the main text of this paper comprises four parts. In the first part, the evolution of scatter-hoarding behavior is discussed. In the second part, the process of scatter hoarding is divided into four sections. First, we consider how hoarding animals select their hoarding targets, including (i) the determination of seed quality by hoarding animals, (ii) the effect of nutrients inside the seeds on animal hoarding, (iii) the effect of seed size on animal hoarding, and (iv) the effect of secondary metabolites inside the seeds on animal hoarding. Second, we consider the delivery and storage of seeds by animals. Third, we review the retrieval behavior of hoarding animals (e.g., spatial memory, particular path, and relevant direct clues). In the third part of the paper, we elaborate the influence of animal scatter-hoarding behavior on the regeneration of plant populations. A number of problems are discussed in detail (i.e., the dispersion effect of scatter-hoarding animals on plant seeds, the dispersion mechanism of plant seeds, the negative effects of scatter-hoarding animals on plant populations, and the adaption strategies of plant populations.) In the last part of this paper, the substantial content is thoroughly summarized. Specifically, this paper is focused on animal scatter-hoarding behavior and its impact on the regeneration of plant populations. These results should be helpful for understanding the mutualism that exists between hoarding animals and plant species, thereby revealing the species-specific functions of hoarding animals in ecological systems. Ultimately, this paper is intended to provide a scientific basis for the protection of biodiversity.