Tese
Uma abordagem funcional entre espécies arbóreas nativas e exóticas invasoras coocorrentes na floresta Atlântica
Fecha
2023-02-17Autor
Dreyer, Jaqueline Beatriz Brixner
Institución
Resumen
Invasive species are a growing threat to natural plant communities’ conservation. Many
hypotheses seek to answer how non-native species may successfully invade new
environments and what drives their success over resident native species. In this sense, this
thesis aimed to investigate differences between native and invasive tree species that co-occur
in the subtropical Atlantic Forest through a functional approach. In particular, our aim was to
understand how species differ in terms of survival and competition, and reproduction and seed
dispersal strategies, that are key stages in the biological invasion process. So, the thesis was
structured in two chapters. In Chapter I, the aim was to characterize fruit and seed functional
traits of six tree species, three native (Psidium cattleianum Sabine, Schinus terebinthifolia
Raddi, and Cupania vernalis Cambess) and three invasive species (Psidium guajava L.,
Ligustrum lucidum W. T. Aiton, and Eriobotrya japonica (Thunb.) Lindl.), in order to
understand how species differ in their reproductive and dispersal strategies. Moreover, we
aimed to evaluate the functional role similarity between each group through the analysis of
morphological functional traits of their fruiting interaction partners. In general, fleshy-fruited
native and invasive species differed in their reproductive strategies. Furthermore, the invasive
species interacted with a large number of similar frugivores, partially overlapping their
functional roles with native species. Thus, the invasive species in this study can compete with
natives for seed dispersers disrupting mutualistic frugivory interactions. For Chapter II, only
the two congener species, the native P. cattleianum and the invasive P. guajava, were selected.
The objective was to evaluate the plants ecological performance and their competitive ability
for resources in a future climate change scenario. The study was conducted in a greenhouse
where plants were grown in pots. Morphophysiological responses to three soil water
availability conditions and two plant densities, alone or in competition, were evaluated. The
species showed greater responses to water stress than for competition. In general, the invasive
species showed higher physiological efficiency due to higher photosynthetic rates and
biomass production even under conditions of resource-poor environments. Finally, the results
of this thesis highlight that invasive species have partially different reproductive strategies
and resource use allocation compared to native species, which reflect on their ability to invade
ecosystems.