Abstract
Ecología Austral, 24:83-93 (2014)Studies on the relationship between the richness of native and exotic plants have generated conflicting evidence depending, among others, on the spatial scale of analysis. This study assessed the invasion by exotic species in natural grasslands of Uruguay at a regional scale. We analyzed 313 vegetation census from four geomorphological regions: Cuesta Basaltica, Cuenca Sedimentaria, Centro Sur and Sierras del Este. The results showed that the relationship between native and exotic richness was negative for Centro Sur while the effect of native species richness on exotic plant cover was negative for Centro Sur and Cuenca Sedimentaria. In most analyses, the functional type C4 grasses was negatively associated with the exotic richness and cover, and strongly inhibits Cynodon dactylon, the only C4 exotic grass species present in the sites. Conversely, C3 species showed irregular patterns of association with the exotics. Also, exotic richness was positively related with the percentage of agricultural use and vegetation cover. Our results suggest that propagule pressure and productivity favour the introduction and establishment of exotic species, but they are largely controlled by the composition of the resident community, in particular by the presence of C4 perennial grasses, which are the group with the highest cover in these communities. This could explain the very low incidence of exotic species in Uruguayan grasslands.
Highlights
Patterns of invasion in grasslands of Uruguay at a regional scale: Studies on the relationship between the richness of native and exotic plants have generated conflicting evidence depending, among others, on the spatial scale of analysis
This study assessed the invasion by exotic species in natural grasslands of Uruguay at a regional scale
The results showed that the relationship between native and exotic richness was negative for Centro Sur while the effect of native species richness on exotic plant cover was negative for Centro Sur and Cuenca Sedimentaria
Summary
En este trabajo se evaluó la invasión por especies exóticas de los pastizales naturales de Uruguay, a escala regional. Cuando los análisis se realizaron por tipos funcionales, se observó que en la mayoría de las regiones la riqueza de las gramíneas C4 está asociada negativamente con las exóticas en su conjunto y fuertemente relacionada con la cobertura de Cynodon dactylon, la única especie exótica de este tipo funcional. Nuestros resultados sugieren que si bien la presión de propágulos y la productividad regional favorecerían la introducción y establecimiento de las especies exóticas, el proceso de invasión en los pastizales naturales de Uruguay estaría en gran medida regulado por la composición funcional de la vegetación nativa, en particular por la presencia de gramíneas C4 perennes, que constituyen el grupo con mayor cobertura en estas comunidades. [Palabras clave: especies exóticas, invasibilidad, gramíneas nativas C4, resistencia biótica, riqueza, tipos funcionales]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
