Effects of macrocyclic lactone anthelmintics on seed germination and seedling establishment of grassland species

内寄生虫和体外寄生虫是羊和牛等家畜健康状况不佳和生产力低下的主要原因。为了控制这些寄生虫，世界各地的家养物种都使用了广泛的驱虫剂，例如大环内酯类(MLS)。施药后，进入环境的主要途径是粪便排泄。随后，许多非靶标生物可能会受到不利影响。MLS对分解者，特别是节肢动物的负面影响已经得到了很好的研究，但驱虫剂对幼苗出苗的评估几乎完全被忽视。放牧植被中稀有和濒危的植物物种可能受益于有蹄类动物内寄生的种子传播，这是一个常见的和有充分记录的现象。特别是绵羊已被证明是有效的种子传播媒介，从而成功地在新的地点建立了植物个体。因此，可以预期，对牲畜传播种子的有效性的任何负面影响都将具有重大的一般生态意义；特别是在自然保护和生态恢复方面。植物种群的生存和持续很大程度上依赖于繁殖，因此种子萌发和成苗是植物个体生命中最关键的阶段。如果没有成功的萌发和建立，种群将面临灭绝的威胁。种子萌发过程受生物环境和非生物环境条件的影响。当种子环境发生变化时，很可能会对出苗产生影响。在这方面，MLS作为驱虫剂应用于牲畜，对种子活力、种子萌发和幼苗建立可能产生直接负面影响，威胁到有效的种子传播、萌发和幼苗建立。据我们所知，第一项直接涉及驱虫剂对种子萌发影响的研究是由该提案的项目组进行的(Eichberg等人，2016年)。在这项研究中，我们发现驱虫剂Cydectin及其活性成分对种子萌发有明显的负面影响(Eichberg等人，2016)。在这种情况下，对MLS对种子萌发、出苗和成苗的影响的了解非常有限，需要进行进一步的研究。为此，我们想评估i)在Eichberg等人的研究中发现的反应模式。(2)不同的MLs在多大程度上对种子萌发、出苗和建立表现出相似的影响。

Endo- and ectoparasites are a major cause of ill health and poor productivity in domestic animals, such as sheep and cattle. In order to control these parasites a broad spectrum of anthelmintics, e.g. macrocyclic lactones (MLs), is administered to domestic species worldwide. After application, the main path into the environment is via faeces excretion. Subsequently, many non-target organisms may be adversely affected. Well-studied are the negative effects of MLs on decomposers, especially arthropods but the assessment of anthelmintics on seedling emergence has been almost completely neglected.Rare and endangered plant species in grazed vegetation might profit from endozoochorous dispersal of seeds by ungulates, which is a common and well-documented phenomenon. Especially sheep have been proven to be effective seed dispersal vectors resulting in a successful establishment of plant individuals at new sites. Thus, it can be expected that any negative effect on the effectiveness of seed dispersal by livestock will be of significant general ecological relevance; especially in nature conservation and ecological restoration. Survival and persistence of plant populations strongly depend on reproduction, thus seed germination and seedling establishment are the most critical stages in the life of plant individuals. Without successful germination and establishment, populations are threatened by extinction. Germination processes are affected by the biotic environment, and by abiotic environmental conditions. When the environment of seeds changes, effects on seedling emergence are very likely to occur. In this context, possible direct negative effects of MLs, administered to livestock as anthelmintic formulations, on seed viability, seed germination and seedling establishment threaten effective seed dispersal, germination and seedling establishment. To our knowledge the first study that directly addressed the effect of an anthelmintic on seed germination was conducted by the project group of this proposal (Eichberg et al., 2016). In this study, we found clear negative effects of the anthelmintic Cydectin and its active ingredient on seed germination (Eichberg et al., 2016). This situation of very limited knowledge about the effects of MLs on germination, seedling emergence and seedling establishment calls for further research. To this end, we want to assess i) whether the response patterns found in the study of Eichberg et al. (2016) can be confirmed for a wider spectrum of plant species and ii) to which degree different MLs show similar effects on seed germination, seedling emergence and establishment.