Post‐dispersal seed predation is an important determinant of plant recruitment. Although many plant species are dispersed following consumption by omnivorous vertebrates, the potential for these dispersal agents to indirectly affect seed fate by modifying seed predator behavior is poorly understood. We evaluated the hypothesis that the scat of an omnivorous vertebrate (coyote, Canis latrans), which is also a rodent predator, would reduce seed predation by rodent granivores. We also hypothesized that scat would lead to increased removal by arthropod seed predators by providing a resource that attracts ants and other arthropods. We examined the role of omnivore deposition on seed predation of two animal‐dispersed species that differed in size: Larger Prunus serotina seeds are attacked only by rodents, whereas smaller Rubus allegheniensis seeds are attacked by arthropods and rodents. Using an experiment that manipulated the presence of coyote scat and access by different granivore guilds, we found that scat reduced the total number of seeds removed from full‐access depots by 12%, but it increased the total number of seeds removed from arthropod‐only depots by 43%. Rodent removal of P. serotina seeds was 21% lower in the presence of scat. Scat composition was also important in affecting rodent seed predation, with seed predation 50% lower in the presence of meat‐rich scat compared with mixed or fruit‐rich scat. Arthropod removal of R. allegheniensis seeds was 43% higher in the presence of scat. Prunus serotina seeds were generally removed at greater rates than R. allegheniensis seeds in full‐access trays; however, scat reduced this difference in removal rates from 37% more P. serotina seeds removed to 18% more P. serotina seeds removed. These findings illuminate a new pathway through which omnivores may influence plant populations by modifying post‐dispersal seed predation by arthropods and rodents. Moreover, our results indicate that the ultimate effect of vertebrate omnivores on seed survival in a given region may depend upon omnivore diet, dominant seed predator guilds, and differences in granivore seed preference.

中文翻译：

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杂食性中捕食者改变杂食性分散种子的捕食

分散后种子的捕食是植物募集的重要决定因素。尽管杂食性脊椎动物食用后会分散许多植物物种，但人们对这些分散剂通过改变种子捕食者行为间接影响种子命运的潜力了解甚少。我们评估了一个假设，即杂食性脊椎动物（土狼，Canis latrans）的粪便也是啮齿动物的食肉动物，会减少啮齿动物食肉动物的种子捕食。我们还假设，粪便会通过提供一种吸引蚂蚁和其他节肢动物的资源来导致节肢动物种子天敌的清除增加。我们研究了杂食动物沉积在两种大小不同的动物分散物种的种子捕食中的作用：较大的李子血清种子仅受到啮齿动物的攻击，而较小的悬钩子种子受到节肢动物和啮齿动物的攻击。通过对土狼粪便的存在和不同食肉动物行会的进入进行操纵的实验，我们发现粪便使从完全进入的仓库中移走的种子总数减少了12％，但是却增加了从节肢动物中移出的种子总数仓库数量增加了43％。在有粪便的情况下，啮齿类动物血清种子的啮齿动物去除率降低了21％。粪便成分对影响啮齿动物的种子捕食也很重要，与混合或富含水果的粪便相比，存在肉食丰富的粪便的情况下，种子捕食作用降低50％。在粪便存在的情况下，节肢动物对Allegheniensis种子的去除率高43％。李酸橙木种子在大于率普遍除去R. allegheniensis的完全访问盘种子; 然而，SCAT减少去除率这种差异的37％以上P.酸橙木除去〜18％更多的种子P.酸橙木除去种子。这些发现揭示了杂食动物可以通过改变节肢动物和啮齿类动物的散布后种子捕食来影响植物种群的新途径。此外，我们的结果表明，脊椎动物杂食动物对给定区域内种子生存的最终影响可能取决于杂食动物饮食，主要的种子捕食者行会以及食肉动物种子偏好的差异。