Non-native plant legacies: site-dependent effects on deadwood fungal community species and functions

Baptiste Joseph Wijas, Habacuc Flores-Moreno, Steven D Allison, Lucas A Cernusak, Alexander W Cheeseman, Jeff R Powell , Amy E Zanne

1) The introduction of non-native species has consequences for ecosystem functions including deadwood decay. Non-native deadwood is a novel substrate for consumers, such as fungi, which drive large portions of carbon cycling, but their response to a novel substrate may depend on their local communities and surrounding environmental conditions.
2) We quantified decomposition rates, chemical composition and fungal communities of native and non-native deadwood across dry savanna and wet rainforest sites. We used six and five native angiosperm species in the rainforest and savanna, respectively as well as a non-native conifer in both.
3) Wood-dwelling fungal communities differed between sites and specific fungal clades showed different relative abundances in native versus non-native wood depending on the site. Non-native deadwood decayed slower than native deadwood with similar chemical properties in the rainforest but not in the savanna.
4) Our results suggest that depending on the environmental conditions in which non-native plants are introduced, the response of ecological communities and ecosystem processes differ. Such effects could be further amplified as non-native introductions become invasive, including the spread of decay and disease, forms in which carbon and nutrients are released and/or function of important plant-fungal relationships.