Instituto de Investigación Multidisciplinario en Ciencia y Tecnología, Universidad de La Serena, La Serena, Chile.
Instituto de Ecología y Biodiversidad (IEB), Las Palmeras, 3425, Ñuñoa, Chile.
Sci Rep. 2020 Apr 8;10(1):6106. doi: 10.1038/s41598-020-62704-6.
Many plant species bear fruits that suggest adaptation to seed dispersal by extinct megafauna. Present-day seed dispersal of these megafaunal plants is carried out by rodents, which can act as predators or dispersers; whether this interaction is primarily positive or negative can depend on the context. Here, we parameterized a stochastic model using data from the field and experimental arenas to estimate the effect of rodents on the recruitment of Myrcianthes coquimbensis -an Atacama Desert shrub with megafaunal fruits- and examine whether environmental conditions can alter the sign and strength of these rodent-plant interactions. We show that the outcome of these interactions is context-dependent: in wet conditions seed removal by rodents negatively impacts the recruitment probability of M. coquimbensis; in contrast, in dry conditions, the interaction with rodents increases recruitment success. In all cases, the strength of the effect of rodents on the recruitment success was determined mainly by their role as dispersers, which could be positive or negative. This study demonstrates that by caching seeds, rodents can be effective dispersers of a megafaunal fruit plant, but that the sign and magnitude of their effect on recruitment changes as a function of the environmental context in which the interaction occurs.
许多植物物种结出的果实表明它们适应了已灭绝的巨型动物传播种子。这些巨型动物植物的现代种子传播是由啮齿动物进行的，啮齿动物既可以充当捕食者，也可以充当传播者；这种相互作用是主要是积极的还是消极的，可能取决于具体情况。在这里，我们使用来自实地和实验场的数据来参数化一个随机模型，以估计啮齿动物对迈尔西亚特克斯库昆本西斯（一种安第斯沙漠灌木，具有巨型动物果实）的繁殖的影响，并检查环境条件是否可以改变这些啮齿动物与植物的相互作用的符号和强度。我们表明，这些相互作用的结果是依赖于背景的：在潮湿条件下，啮齿动物的种子移除会对 M. coquimbensis 的繁殖概率产生负面影响；相比之下，在干燥条件下，与啮齿动物的相互作用会增加繁殖成功率。在所有情况下，啮齿动物对繁殖成功率的影响强度主要取决于它们作为传播者的作用，这可能是积极的，也可能是消极的。本研究表明，通过藏种，啮齿动物可以成为一种巨型动物果实植物的有效传播者，但它们对繁殖的影响的符号和大小会随着相互作用发生的环境背景而变化。
