How are herbivorous consumers limited by multiple resources simultaneously? - Development and definition of co-limitation types in a generally applicable theoretical framework

近年来，越来越多的研究表明，生物的生长在任何时候都不受一种资源的限制。共同限制，即多种资源同时限制生物体的生长，是生态学研究中的一个新兴课题。到目前为止，共同限制的理论概念主要是针对初级生产者（植物/藻类）。几种类型的共同限制，即生物体如何共同限制的方式，被提出用于植物，其中一些可能也适用于消费者。然而，消费者在各种资源获取策略上与植物有着根本的不同，这表明需要新的共同限制类型。此外，研究中提出的植物共限制类型的定义不一致。因此，需要一个总体框架，其中明确界定不同类型的共同限制。本项目旨在为消费者共同限制制定一个普遍适用的理论框架，其中明确定义和明确描述了不同类型的共同限制。该项目将重点关注草食性消费者，因为他们对资源数量和质量的限制特别敏感。我将回顾现有的营养生态学理论，对草食动物的特征和食物种类进行全面的文献调查。这些知识对于发展不同类型的共同限制是必不可少的，这些共同限制将被描述为(i)数学上的，（ii）图形上的，（iii）在案例研究的帮助下，并在一个新的理论框架中相互联系。这一框架将提高对消费者共同限制背后机制的理解，并为可以进行经验检验的假设的发展提供基础。因此，所提出的框架的阐述对共同限制研究的进一步发展具有至关重要的意义。

Recently, a growing number of studies have shown that the growth of organisms is not limited by only one resource at any one time. Co-limitation, i.e., the simultaneous limitation of an organism¿s growth by multiple resources, is an emerging topic in ecological research. As yet, theoretical concepts for co-limitation are mainly derived for primary producers (plants/algae). Several types of co-limitation, i.e., the way how organisms are co-limited, were proposed for plants and some of which can be probably applied to consumers as well. However, consumers differ fundamentally from plants in their various resource acquisition strategies, suggesting to the need for new co-limitation types. Additionally, the proposed co-limitation types for plants are inconsistently defined among studies. Therefore, a general framework is required in which the different types of co-limitation are clearly defined. The present project aims to develop a generally applicable theoretical framework for consumer co-limitation, in which the different types of co-limitation are clearly defined and explicitly described. The project will focus on herbivorous consumers as they are especially sensitive to constraints in resource quantity and quality. I will review existing theories in nutritional ecology and conduct a comprehensive literature survey on herbivore characteristics and food categories. This knowledge is essential to develop different types of co-limitation, which will be described (i) mathematically, (ii) graphically, (iii) with help of case studies, and linked to each other in a novel theoretical framework. This framework will improve the understanding of mechanisms behind consumer co-limitation and provide a basis for the development of hypotheses which can be tested empirically. Thus, the elaboration of the proposed framework is of crucial importance in the further development of research on co-limitation.