Trait variation, trade-offs, and attributes may contribute to colonization and range expansion of a globally distributed weed.

Abstract

PREMISE OF THE STUDY\nTrait variation, trade-offs, and attributes can facilitate colonization and range expansion. We explored how those trait features compare between ancestral and non-native populations of the globally distributed weed Centaurea solstitialis.\n\n\nMETHODS\nWe measured traits related to survival, size, reproduction, and dispersal in field sampling following major environmental gradients; that of elevation in Anatolia (ancestral range) and that of precipitation in Argentina (non-native range). We also estimated abundance.\n\n\nKEY RESULTS\nWe found that overall variation in traits in ancestral populations was similar to that in non-native populations. Only one trait, seed mass, displayed greater variation in ancestral than non-native populations; coincidentally, seed mass has been shown to track global range expansion of C. solstitialis. Traits displayed several associations, among which seed mass and number were positively related in both ranges. Many traits varied with elevation in the ancestral range, whereas none varied with precipitation in the non-native one. Interestingly, most traits varying with elevation within the ancestral range also displayed differences in attributes between ancestral and non-native ranges. Unexpectedly, ancestral plants were more fecund than non-native plants, but density was greater in the non-native than ancestral range, indicating that C. solstitialis survives at larger proportions in the non-native than ancestral range.\n\n\nCONCLUSIONS\nOur results suggest that maintaining levels of trait variation in non-native populations comparable to those in ancestral populations, avoiding trait trade-offs, and developing differences in trait attributes between ranges can play a major role in the success of many weeds in novel environments. This article is protected by copyright. All rights reserved.