Mycoheterotrophy is a particular mode of life in which
plants obtain carbohydrates from their associated fungal partners, instead of
by using photosynthesis. Due to the complexity of mycorrhizal interactions
and challenges in assessing the outcomes of this symbiosis, cheating has
remained a poorly researched topic in plant ecology. This thesis aimed to
shed light on the diversity, ecology and distribution of mycoheterotrophic
interactions. In my approach, I considered that different drivers may be
important at different scales and studied four levels of ecological complexity.
In chapter 2, the specificity of mycoheterotrophic interactions within the
arbuscular mycorrhizal symbiosis was assessed at the organism level. In
chapter 3, biotic interactions between plants and fungi were studied in the
framework of mycoheterotrophic plant coexistence scenarios at the population
level. In addition, edaphic abiotic factors potentially influencing the
occurrence of mycoheterotrophic plants were assessed at the community level
in chapter 4, through a comparison of soil chemistry and nutrients in plots
where mycoheterotrophic plants were present with those lacking these plants.
Finally, in chapter 5 I derived the global drivers for the distribution of
mycoheterotrophy for both the arbuscular and the ectomycorrhizal symbiosis
from species occurrence data of these plants.
Conservation Biolog