Effect of Invasive Plant Species on Temperate Wetland Plant Diversity

• Published in: Conservation biology 2004-08, Vol.18 (4), p.1132-1138
• Main Authors: HOULAHAN, JEFF E., FINDLAY, C. SCOTT
• Format: Article
• Language: English
• Subjects: Animal, plant and microbial ecology; Applied ecology; Biological and medical sciences; competitive exclusion; Conservation biology; Conservation, protection and management of environment and wildlife; Ecological invasion; especies invasoras; exclusión competitiva; Freshwater; Fundamental and applied biological sciences. Psychology; humedales; Hydrocharis morsus-ranae; Introduced species; Invasive species; Lythrum salicaria; Native plants; Native species; Nuphar variegatum; Parks, reserves, wildlife conservation. Endangered species: population survey and restocking; Phalaris arundinacea; Plants; Research Notes; Rhamnus frangula; riqueza de especies; Salix petiolaris; Species; Species diversity; species richness; Typha angustifolia; Typha latifolia; Wetlands
• ISSN: 0888-8892; 1523-1739
• DOI: 10.1111/j.1523-1739.2004.00391.x

Invasive species are a major threat to global biodiversity and an important cause of biotic homogenization of ecosystems. Exotic plants have been identified as a particular concern because of the widely held belief that they competitively exclude native plant species. We examined the correlation between native and invasive species richness in 58 Ontario inland wetlands. The relationship between exotic and native species richness was positive even when we controlled for important covarying factors. In addition, we examined the relationship between the abundance of four native species (Typha latifolia, T. angustifolia, Salix petiolaris, Nuphar variegatum) and four invasive species (Lythrum salicaria, Hydrocharis morsus-ranae, Phalaris arundinacea, Rhamnus frangula) that often dominate temperate wetlands and native and rare native species richness. Exotic species were no more likely to dominate a wetland than native species, and the proportion of dominant exotic species that had a significant negative effect on the native plant community was the same as the proportion of native species with a significant negative effect. We conclude that the key to conservation of inland wetland biodiversity is to discourage the spread of community dominants, regardless of geographical origin.