Maintenance of biodiversity through mutualistic networks between arbuscular mycorrhizal fungi and plants: robustness against human disturbance and climate change

丛枝菌根真菌（Glomeromycota）是热带地区最重要的真菌，在营养贫乏的环境中为绝大多数植物（包括几乎所有树种）提供矿物质至关重要。因此，了解植物-真菌共生关系对于了解热带生态系统的生物学和生态学是必不可少的，并为全球变化预期下的监测和保护工作提供指导。与对鸟类、哺乳动物、土壤节肢动物或水生动物的调查相反，在热带地区很少研究丛枝菌根真菌群落，在高海拔的厄瓜多尔帕拉莫斯也一无所知。生态研究中真菌生物的重要性被广泛低估以及缺乏监测系统的主要原因是研究这些生物的方法在技术上存在困难。近年来，分子生物学方法被越来越多地应用于丛枝菌根真菌（AMF）的鉴定，因为形态学特征被证明是不够的，即使详细的描述。同时，巢式PCR、克隆和桑格测序是鉴定真菌的成熟方法，申请人基于这些方法提供了安第斯热带山地森林AMF序列的全面数据集。生态网络理论的应用表明，所有研究的AMF-组合显着嵌套。根据网络模拟，显着的嵌套，很少联系的物种优先连接到高度连锁的物种的子集的观察，表明真菌和植物的丰富性是由互惠互动促进的。因此，AMF不仅改善了植物个体的营养，而且还将当地稀有植物物种和真菌整合并保存在一个共同的网络中。因此，监测AMF社区之间的地块之间的变化沿着一个大的海拔梯度，目前在厄瓜多尔安第斯山脉将提供数据，可以解释在功能层面上的气候变化。对厄瓜多尔最常见的被火毁坏的场址，与未受破坏的场址相比，也可以进行类似的分析。需要评估AMF对场地标高和火灾的敏感性。有必要知道AMF是否可以在与海拔和干扰相关的模块之间转换，以评估真菌对气候变化或火灾影响的弹性或敏感性，从而对植物建立和生长产生影响。因此，为了安装AMF监测系统，需要与厄瓜多尔合作伙伴一起进行进一步调查，包括低海拔和高海拔地区，以估计AMF作为气候变化和火灾破坏指示生物的敏感性。

Arbuscular mycorrhizal fungi (Glomeromycota) are the most prominent mycobionts in the tropics and crucial for providing minerals to the vast majority of plants including nearly all tree species in the nutrient poor environments. Thus, knowledge of the mutualistic plant-fungus associations is indispensable for understanding the biology and ecology of tropical ecosystems and give guidelines for monitoring and conservation efforts under global change expectations. In contrast to surveys on birds, mammals, soil arthropods or aquatic animals, arbuscular mycorrhizal fungal communities have been rarely studied in the tropics, and nothing is known from the high elevation Ecuadorian Páramos. The main reason for the widespread underestimation of the importance of mycobionts in ecological studies and the lack of a monitoring system is the technically difficult approach to the organisms. During recent years molecular methods were increasingly applied to identify the arbuscular mycorrhizal fungi (AMF) because morphological features proved as insufficient even with detailed description. Meanwhile, nested PCR, cloning and Sanger sequencing are well-established methods for identification of the fungi and a comprehensive data set of AMF sequences has been provided for the Andean tropical mountain forest based on these methods by the applicant. Application of ecological network theory revealed that all studied AMF-assemblages were significantly nested. According to network simulations, significant nestedness, the observation that rarely linked species preferentially link to subsets of highly linked species, indicates that richness of fungi and plants are promoted by the mutualistic interaction. AMF, therefore, not only improve nutrition of individual plants but also integrate and thus preserve locally rare plant species and fungi in a common network. Thus, monitoring the changes of AMF communities among plots along a large elevation gradient as present in the Ecuadorian Andeans will supply data that can be interpreted on a functional level with respect to climate changes. Similar analyses can be carried out for fire-destroyed sites, most common in Ecuador, in comparison to undisturbed sites. The sensitivity of AMF to site elevation and fire needs to be assessed. It is necessary to know if AMF can shift among the modules related to elevation and disturbance to evaluate in as much the mycobionts are resilient or sensitive to climate change or fire affection with consequences for plant establishment and growth. Thus, to install a monitoring system for AMF, further investigation together with the Ecuadorian partners including low and high elevation is necessary to estimate the sensitivity of AMF as indicator organisms for climate change and fire destructions.