Forests are not immune to plant invasions: phenotypic plasticity and local adaptation allow Prunella vulgaris to colonize a temperate evergreen rainforest
- 609 Downloads
In the South American temperate evergreen rainforest (Valdivian forest), invasive plants are mainly restricted to open sites, being rare in the shaded understory. This is consistent with the notion of closed-canopy forests as communities relatively resistant to plant invasions. However, alien plants able to develop shade tolerance could be a threat to this unique forest. Phenotypic plasticity and local adaptation are two mechanisms enhancing invasiveness. Phenotypic plasticity can promote local adaptation by facilitating the establishment and persistence of invasive species in novel environments. We investigated the role of these processes in the recent colonization of Valdivian forest understory by the perennial alien herb Prunella vulgaris from nearby populations in open sites. Using reciprocal transplants, we found local adaptation between populations. Field data showed that the shade environment selected for taller plants and greater specific leaf areas. We found population differentiation and within-population genetic variation in both mean values and reaction norms to light variation of several ecophysiological traits in common gardens from seeds collected in sun and shade populations. The colonization of the forest resulted in a reduction of plastic responses to light variation, which is consistent with the occurrence of genetic assimilation and suggests that P. vulgaris individuals adapted to the shade have reduced probabilities to return to open sites. All results taken together confirm the potential for rapid evolution of shade tolerance in P. vulgaris and suggest that this alien species may pose a threat to the native understory flora of Valdivian forest.
KeywordsAdaptive divergence Evolutionary response Genetic assimilation Invasive plants Temperate rainforest
We are grateful to Fernando Carrasco for field help. OG wants to acknowledge financial support provided by the Spanish Ministry for Education and Science grants RASINV GL2004-04884-C02 02/BOS (as part of the coordinate project RINVE). A CSIC-CONICYT collaborative grant to FV and EG contributed to the development of this study.
- Arroyo MTK, Marticorena C, Matthei O et al (2000) Plant invasions in Chile: present patterns and future predictions. In: Mooney HA, Hobbs RJ (eds) Invasive species in a changing world. Island Press, USA, pp 385–421Google Scholar
- Dorsch K, Böhm F, Sepúlveda F (2003) Hydrochemistry and hydrology of the Puyehue Cordón, Caulle geothermal systems, Chile. Geowissenschaftliches Lateinamerika-kolloquiem. TU Bergakademie FreibergGoogle Scholar
- Matthei OJ (1995) Manual de las malezas que crecen en Chile. Alfabeta impresiones, Santiago de ChileGoogle Scholar
- Philippi RA (1881) Catálogo de las plantas cultivadas para el Jardín Botánico de Santiago hasta el 1° de Mayo de 1881. Anales Universidad de Chile 59:519–581Google Scholar
- Pigliucci M (2001) Phenotypic plasticity: beyond nature and nurture. John Hopkins University Press, BaltimoreGoogle Scholar
- Pyšek P, Richardson DM (2007) Traits associated with invasiveness in alien plants: where do we stand? In: Caldwell MM (ed) Biological invasions. Springer, Berlin, pp 97–125Google Scholar
- Ugarte E, Fuentes N, Klotz S (2010) European plant in Southern South America, unwanted visitors? In: Settele J, Penev L, Georgiev T, Grabaum R, Grobelnik V, Hammen V, Klotz S, Kotarac M, Kuhn I (eds) Atlas of biodiversity risks—from Europe to the globe, from stories to maps. Pensoft, SofiaGoogle Scholar