Competitive effects hinder the recolonization of native species in environments densely occupied by one invasive exotic species
Nenhuma Miniatura disponível
Data
2018-09
Título da Revista
ISSN da Revista
Título de Volume
Editor
Resumo
The responses of native plants to competition with invasive plants depend mainly on
the density of the invasive plants and on the ability of the native plants to compete
for resources. In this study, we tested the influence of the invasive exotic Urochloa
arrecta (Poaceae) on the early colonization of two native species (Pontederia cordata
and Leersia hexandra) of aquatic macrophytes. Our hypotheses were (i) the competitive
effects of U. arrecta on the native species P. cordata and L. hexandra are densitydependent
and that (ii) these species respond differently to competitive interactions with
the invasive species. We conducted the experiments in a greenhouse and in the field,
in a tropical reservoir. The biomass of U. arrecta (ranging from 206.2 to 447.1 g) was
manipulated in the greenhouse in trays with different densities. After the establishment
of the invasive species, we added P. cordata and L. hexandra propagules to each
tray. In the field, a propagule of P. cordata was planted in 36 sites with different
densities of U. arrecta. The biomass and length of the natives and the biomass of
the invasive species were measured in the greenhouse and in the field experiments.
The biomass and length of the native plants decreased with increasing biomass of the
exotic species in both experiments, showing that the competition between U. arrecta
and native species depends on the density of the exotic species. The root:shoot ratio of
L. hexandra decreased with increasing U. arrecta biomass, but the opposite occurred
for P. cordata. These results indicate that native species exhibit different strategies of
biomass allocation when interacting with U. arrecta. The strong competitive effects of
U. arrecta and the different responses of the native species help to explain the reduced
diversity of native macrophytes observed in sites colonized by U. arrecta. The results
also suggest that in a scenario of dominance of exotic species, recolonization by native
macrophytes is unlike to occur naturally and without human interventions that reduce
the biomass of the exotic species.
Descrição
Palavras-chave
Competition, Resource competition, Non-native macrophytes, Density-dependent effect, Poaceae
Citação
MICHELAN, Thaisa S.; THOMAZ, Sidinei M.; BANDO, Fabielle M.; BINI, Luis M. Competitive effects hinder the recolonization of native species in environments densely occupied by one invasive exotic species. Frontiers in Plant Science, Lausanne, v. 9, p. 1261, Sept. 2018. Doi: 10.3389/fpls.2018.01261. Disponível em: https://pubmed.ncbi.nlm.nih.gov/30233613/. Acesso em: 10 jan. 2023.