Invasion of a xeric forest by an exotic tree species in Argentina: Impacts on the diversity of arbuscular mycorrhizal fungi and pre-existing mutualistic relationships

ABSTRACT

This study aimed to analyse the effects of invasion by the exotic Ligustrum lucidum on mycorrhizal associations in forests of Celtis tala, and to determine the role that these fungi play in the invasion process. We analyzed colonization and response to mycorrhization of both plant species under greenhouse conditions after inoculation with soil obtained from patches of non-invaded native forests and invaded forests. The spores present in pots at the end of the experiment were counted and identified. Colonization of L. lucidum was greater in plants inoculated with invaded forest soil, whereas colonization of C. tala was greater in plants inoculated with non-invaded native forest soil. Principal component analysis of fungal species abundance showed differences in AMF composition according to host plant and forest type. The results show that L. lucidum establishes symbiosis with native AMF, which triggers changes in community structure. These changes favored the mycorrhization of L. lucidum and interfered with the mycorrhization of C. tala. AMF may have either a direct or indirect role in the invasion process, not only benefiting the invasive species but also preventing the regeneration of native plants.

Keywords:
biological invasion; Glomeromycota; mycorrhizal colonization; xeric forest; Celtis tala; Ligustrum lucidum