Data from: Adaptive plasticity and niche expansion in an invasive thistle

Alternately, the typically disturbed invaded range may select for a plastic, generalist strategy, making phenotypic plasticity the main driver of invasion success. To distinguish between these hypotheses, we performed a field common garden and tested for genetically based phenotypic differentiation, resource allocation shifts in response to water limitation, and local adaptation to the environmental gradient which describes the source locations for native and invasive populations of diffuse knapweed (Centaurea diffusa).

Plants were grown in an experimental field in France (naturalized range) under water addition and limitation conditions. After accounting for phenotypic variation arising from environmental differences among collection locations, we found evidence of genetic variation between the invasive and native populations for most morphological and life-history traits under study. Invasive C. diffusa populations produced larger, later maturing, and therefore potentially fitter individuals than native populations.

Evidence for local adaptation along a resource allocation trade-off for water limitation tolerance is equivocal. However, native populations do show evidence of local adaptation to an environmental gradient, a relationship which is typically not observed in the invaded range. Broader analysis of the climatic niche inhabited by the species in both ranges suggests that the physiological tolerances of C. diffusa may have expanded in the invaded range.

This observation could be due to selection for plastic, “general-purpose” genotypes with broad environmental tolerances.

Usage notes

Bioclimatic data C. diffusa experimental populations Geographic and climatic information for 14 sampled populations of native and invasive Centaurea diffusa (diffuse knapweed). Also, first three principal components from an analysis of this data. FrbioclimPCA_DKdat.txt Planting information C. diffusa experimental plants Planting information for experimental Centaurea diffusa plants Frdes.txt Occurrence records C. diffusa Records of Centaurea diffusa in Europe and North America, from GBIF.org, downloaded January 9, 2015 Cdif_GBIF_allocc.txt Location information for collected C. diffusa populations Location and collection information for populations of native and invasive Centaurea diffusa (diffuse knapweed) used in the experimental PCA and occurrence PCA.

Popcoord.txt Adjusted location information for collected C. diffusa populations Adjusted location and collection information for populations of native and invasive Centaurea diffusa (diffuse knapweed) used in the experimental PCA and occurrence PCA. Popcoord_worldclim.txt Bioclimatic data for C. diffusa occurrences Bioclimatic data and PCA values for occurrence records of Centaurea diffusa Geographic and climatic information for 662 occurrence records of native and invasive Centaurea diffusa (diffuse knapweed) from North America and Europe.

Occurrence records include records from GBIF.org as well as collected populations. Cdif_allocc_bioclimPCA.txt Trait data at harvest, from C. diffusa common garden Trait data for experimental populations of Centaurea diffusa, measured at harvest. Trait values measured in common field experiment in Montpellier, France, 2011.

File also include the first three principal components from the experimental PCA of the bioclimatic data for these populations. FrTraitClimDat_cline.txt Phenological trait data, from C. diffusa common garden Phenological trait data for experimental populations of Centaurea diffusa, measured throughout experiment Trait values measured in common field experiment in Montpellier, France, 2011. File also include the first three principal components from the experimental PCA of the bioclimatic data for these populations.

FrEnd_cline.txt Repeated measures of traits, from C. diffusa common garden Trait data for experimental populations of Centaurea diffusa, repeated measures. Trait values measured in common field experiment in Montpellier, France, 2011. File also include the first three principal components from the experimental PCA of the bioclimatic data for these populations.

FrTraitClimDat_cline_long.txt FranceCG - code Github repository storing R scripts used in this paper.