Mechanisms Of Invasion Resistance Research Articles

Plant species richness increases resistance to invasion by non‐resident plant species during grassland restoration

AbstractQuestionsDuring restoration of bare subsoil, are planted grassland communities with low species richness more susceptible to invasion by non‐residents than communities augmented by additional species? What are the mechanisms of invasion resistance in early succession?LocationLexington, Virginia, USA (37.8°N, −79.4°W).MethodsWe planted 62 3 × 3 m plots on compacted clay subsoil with 20–21 replicates of three, 12 and 24 native species. Plots were sampled non‐destructively using a stratified random point‐intercept method each summer for 5 yr to determine number of species and percentage cover per species, which were classified as residents (planted), internal non‐residents (planted in other plots) or external non‐residents.ResultsA negative relationship between planted species richness and invasion developed by the fourth year after planting and strengthened thereafter. Plots consisting of a single, highly dominant, resident C3 grass species were vulnerable to invasion. With the exception of one species, which seems to have overcome resistance with a high seed rain, external non‐resident species were less diverse and less abundant in higher diversity plots.ConclusionsIncreased planted species richness was correlated with increased resistance to invasion by non‐residents, and we attribute this effect to a combination of the sampling effect and species complementarity, potentially augmented by high species dominance/low evenness in the low species richness plots.

Mechanisms of invasion resistance: competition among intertidal mussels promotes establishment of invasive species and displacement of native species

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 383:187-197 (2009) - DOI: https://doi.org/10.3354/meps07982 Mechanisms of invasion resistance: competition among intertidal mussels promotes establishment of invasive species and displacement of native species J. S. Shinen1,*, S. G. Morgan2 1Estación Costera de Investigaciones Marinas, Departamento de Ecología, Pontificia Universidad Católica de Chile, Alameda 340, Santiago, Chile 2Bodega Marine Laboratory, Department of Environmental Science and Policy, University of California Davis, PO Box 247, Bodega Bay, California 94923, USA *Email: jlshinen@bio.puc.cl ABSTRACT: Understanding interactions between invasive species and recipient communities is essential to determining whether invasive species will become established and spread. In this study, we explored the role of competition and the specific mechanisms of interaction in limiting the spread of the Mediterranean bay mussel Mytilus galloprovincialis within a Pacific Northwest invasion front. We examined the role of direct (interference) and indirect (exploitation) mechanisms of competition among M. galloprovincialis and 2 native mussels (M. trossulus and M. californianus). As the fastest-growing organisms are often competitively dominant in space-limited systems, such as rocky intertidal communities, we used changes in relative performance (growth and survival) in monocultures and polycultures to assess interactions among mussels. Performance of M. galloprovincialis was always greater than that of the 2 native species of mussels in both field and laboratory manipulations of species composition and density, indicating that interspecific competition did not strongly limit the growth or survival of the invader. Moreover, the presence of M. galloprovincialis consistently led to both reduced growth and survival of M. trossulus. Laboratory studies of mussel feeding and behavior revealed M. galloprovincialis to be a robust interference competitor. The invader restricted movement, smothered and interfered with filter feeding of the 2 native species of mussels. Rather than limiting invasion, interference competition gave M. galloprovincialis a competitive advantage over the native mussels. Our results suggest M. galloprovincialis may have contributed to the displacement of M. trossulus along much of its historic southern range. KEY WORDS: Exploitation competition · Interference competition · Mytilus · Rocky intertidal communities Full text in pdf format PreviousNextCite this article as: Shinen JS, Morgan SG (2009) Mechanisms of invasion resistance: competition among intertidal mussels promotes establishment of invasive species and displacement of native species. Mar Ecol Prog Ser 383:187-197. https://doi.org/10.3354/meps07982 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 383. Online publication date: May 14, 2009 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2009 Inter-Research.