Alien vs. native plants in a Patagonian wetlands: elemental ratios and ecosystem stoichiometric impacts

CUASSOLO, F., .; BALSEIRO, E.,; MODENUTTI, B

BIOLOGICAL INVASIONS

SPRINGER

Año: 2012 vol. 14 p. 179 - 189

1387-3547

Wetlands are subject to invasion by exoticplant species, especially during the dry season whenthey resemble terrestrial systems; therefore, terrestrialplants could exploit this situation to colonize thisenvironment. We analyzed P. anserina invadingPatagonian wetlands in terms of elemental ratios thatwould modify wetland stoichiometry due to organicmatter inputs. We studied the elemental relationship(carbon/nitrogen/phosphorus) of P. anserina in comparisonwith native emergent macrophytes (Eleocharispachicarpa and Carex aematorrhyncha). Theseplant species are common and dominant in thewetland. Additionally, we analyzed the presence ofmycorrhizal fungi in the roots and their proportion ofroot infection. Our study reveals that the invasivespecies presented nutrient (especially phosphorus)allocation in roots and differences in mycorrhizalinfection, with a predominance of arbuscular mycorrhiza,compared with native species. During floodedperiods with the decay of aerial parts, P. anserinastores phosphorus in the roots and releases dissolvedorganic matter of high molecular weight molecules,high color, and a high C-to-nutrient ratio in comparisonwith native macrophytes. These results show thestrategy of an invasive terrestrial plant in temporaryaquatic systems, and how the elemental relationshipsof the invasive plant can modify the stoichiometry ofthe environment.