Data from: The interplay among acorn abundance and rodent behavior drives the spatial pattern of seedling recruitment in mature Mediterranean oak forests

The patterns of seedling recruitment in animal-dispersed plants result from the interactions among environmental and behavioral variables. However, we know little on the contribution and combined effect of both kinds of variables. We designed a field study to assess the interplay between environment (vegetation structure, seed abundance, rodent abundance) and behavior (seed dispersal and predation by rodents, and rooting by wild boars), and their contribution to the spatial patterns of seedling recruitment in a Mediterranean mixed-oak forest. In a spatially explicit design, we monitored intensively all environmental and behavioral variables in fixed points at a small spatial scale from autumn to spring, as well as seedling emergence and survival. Our results revealed that the spatial patterns of seedling emergence were strongly related to acorn availability on the ground, but not by a facilitationeffect of vegetation cover. Rodents changed seed shadows generated by mother trees by dispersing most seeds from shrubby to open areas, but the spatial patterns of acorn dispersal/predation had no direct effect on recruitment. By contrast, rodents had a strong impact on recruitment as pilferers of cached seeds. Rooting by wild boars also reduced recruitment by reducing seed abundance, but also by changing rodent’s behavior towards higher consumption of acorns in situ. Hence, seed abundance and the foraging behavior of scatter-hoarding rodents and wild boars are driving the spatial patterns of seedling recruitment in this mature oak forest, rather than vegetation features. The contribution of vegetation to seedling recruitment (e.g. facilitation by shrubs) may be context dependent, having a little role in closed forests, or being overridden by directed seed dispersal from shrubby to open areas. We warn about the need of using broad approaches that consider the combined action of environment and behavior to improve our knowledge on the dynamics of natural regeneration in forests.

动物传播植物的幼苗更新（seedling recruitment）格局，源于环境变量与行为变量之间的相互作用。然而目前学界对这两类变量的贡献及其联合效应的认知仍较为匮乏。本研究设计了一项野外实验，旨在评估环境因子（植被结构、种子丰度、啮齿动物（rodent）丰度）与行为因子（啮齿动物的种子传播与捕食、野猪（wild boar）的拱土活动）之间的相互作用，以及二者对地中海混生栎林（Mediterranean mixed-oak forest）内幼苗更新空间格局的影响。本研究采用空间显式实验设计，在小尺度固定样点上，于秋季至春季期间对所有环境与行为变量开展高密度监测，同时同步记录幼苗出土与存活情况。研究结果显示，幼苗出土的空间格局与地表橡子（acorn）可获得性显著相关，但不受植被覆盖的促进效应影响。啮齿动物将多数种子从灌丛区域扩散至开阔区域，由此改变了母树产生的种子阴影（seed shadow）格局，但橡子传播/捕食的空间格局对幼苗更新并无直接影响。相较而言，啮齿动物作为贮藏种子的盗食者，对幼苗更新产生了极强的影响。野猪的拱土活动同样会降低幼苗更新率，其作用途径包括降低种子丰度，以及改变啮齿动物的行为模式，使其更多地就地取食橡子。因此，在这片成熟栎林中，驱动幼苗更新空间格局的是种子丰度，以及分散贮藏啮齿动物（scatter-hoarding rodents）与野猪的觅食行为，而非植被特征。植被对幼苗更新的贡献（例如灌丛的促进作用）可能依赖于具体情境：在郁闭森林中其作用微乎其微，或是被从灌丛到开阔区域的定向种子传播所抵消。本研究呼吁学界需采用兼顾环境与行为联合作用的综合性研究方法，以深化对森林自然更新（natural regeneration）动态的认知。