Knowing the invader: increasing knowledge about an invasive plant to improve management

Abstract

Pampas grass is an invasive alien plant with negative consequences for ecosystems, human health, and economy. Although diverse aspects of its biology and the ecology have been studied, some information relevant to its management is still missing. We studied the ecological characteristics of seeds and plants relevant to management and habitat restoration, namely morphological and reproductive traits in female and hermaphrodite plants, flower development, seed longevity, and germinability under different conditions. Female and hermaphrodite plants showed significant differences regarding reproductive traits, but not for morphological traits. Female plants are largely responsible for the dispersal of the species, while hermaphrodite plants primarily serve as pollen donors, contributing to off‐season allergies. In general, seeds of female plants are mature 3–4 weeks from the onset of flower development and are dispersed by wind until after 4 months, but timings are influenced by weather conditions. The species is very adaptable and can germinate in different soils (85% in fluvisols, 65% in podzols, and 35% in solonchak), water salinities (77 and 75% in freshwater, 28 and 38% in mesohaline, and 7 and 35% in polihaline waters, in laboratory and field, respectively), and moisture conditions (50 and 33% in soaked conditions, and 25 and 80% in moistened conditions, in laboratory and field, respectively). Seeds lack dormancy, are short‐lived (up to 1 year in the field and 3 years in optimal storage conditions), and are easily destroyed at 40°C temperatures in dark conditions. Implications of these findings for the management of the species are discussed.