Phenotypic plasticity and contrasting habitat colonization in Festuca pallescens

Abstract

Eight populations of Festuca pallescens (Poaceae) from southern Patagonia (Argentina) were chosen to test whether their morphology and anatomy were associated with climatic and edaphic characteristics of their habitats and to discriminate genetic and plastic components of the variation. Fourteen environmental variables were measured to characterize eight localities. Cluster analysis classified them into four habitats. Principal components analysis based on 22 morphological and anatomical characters of five individuals from each population was performed. This ordination grouped them by habitat. Small plants with a low number of spikelets were found in the xeric habitat, whereas plants of the saline habitat showed a significantly higher number of spikelets. Large plants were characteristic of the humid habitats, but at higher elevations of foothill humid valleys the plants produced few spikelets per panicle with larger lemmas and heavier propagules than those in the coastal humid plains. A larger sample of 10 populations drawn from across the distribution of F. pallescens showed that seed collected at high altitudes were significantly heavier then those collected near sea level. The same characters were measured again 1 year after transplanting to uniform conditions. Significant differences between habitats disappeared. These data showed that phenotypic plasticity allows for diverse habitat colonization of this widespread species. Key words: Gramineae, phenotypical plasticity, seed weight, principal components analysis, ecotypes.

Contrasting ecological breadth of co‐occurring annualPolygonumspecies

“…Indeed, it has long been hypothesized that the success of widespread weed species is due to the great adaptive plasticity of their individuals, which allows them to colonize a variety of habitats successfully (Baker 1965, 1974; Bazzaz 1986) and hence wide geographical ranges as well (Rabinowitz 1981). The results of several recent studies support this hypothesis (Oliva et al . 1993; Williams et al .…”

Functional traits of graminoids in semi‐arid steppes: a test of grazing histories

“…Austin & Sala (2002) showed that leaf N content increased with precipitation across an even wider range of moisture. In a study of phenotypic variation, Oliva et al (1993) found that Festuca pallescens growing in dry areas of Patagonia had shorter, tougher leaves than plants growing in more humid environments. At least in Patagonia, aridity appears to favour grazing-avoidance traits, while tolerance traits, such as higher leaf N, increase with precipitation.…”

Population Differentiation and Plastic Responses to Drought Stress in the Generalist AnnualPolygonum persicaria

“…These results support the view that similar, functionally plastic populations may successfully occupy diverse sites in generalist species. This indicates that highly plastic species may consist of adaptively similar, generalist populations in diverse field habitats rather than narrowly specialized ecotypes (Oliva et al 1993;Williams et al 1995).…”

“…Generalist plant species inhabit a wide range of habitats, including resource-poor and variable sites and may therefore be geographically widespread (Bazzaz 1986;Oliva et al 1993). This ecological breadth can reflect individual phenotypic plasticity, genetic differentiation of populations to local environmental conditions, or a combination of both aspects of variation (Bradshaw 1965;Van Tienderen 1990;Rice and Mack 1991;Emery et al 1994).…”