<p>Botanical seminar, KU-LIFE, October 10, 2008, at 14:15-15:00. Lecture by Sabine G&uuml;sewell, Institute of Integrative Biology, Department of Environmental Sciences, ETH Z&uuml;rich.</p><p>Main building, meeting room, KU-LIFE Rolighedsvej 21, Frederiksberg.</p><p>We investigated the ecological limits of the winter annual forb <em>Erigeron annuus</em> in Switzerland to understand why the species is currently becoming more invasive. Until recently, <em>E. annuus</em> was restricted to the lowlands and to open, disturbed habitats, but it now seems to be spreading upward and into more closed vegetation. <br />To understand what limits the altitudinal range of <em>E. annuus</em>, we surveyed populations along roads between 240 and 1100 m a.s.l., and grew plants in common gardens at 400 and 1000 m. Winter survival was reduced at the current altitudinal limit. High-altitude populations were genetically less diverse than low-altitude populations and did not show evidence of local adaptation.<br />To understand what restricts the colonization of closed habitats, we compared <em>E. annuus</em> to <em>S. gigantea</em>, a species able to invade open and closed habitats. <em>E. annuus</em> was not less plastic in shade-avoidance or shade-tolerance traits than <em>S. gigantea</em>, nor did allelopathic effects differ consistently. However, <em>E. annuus</em> was highly palatable to slugs and strongly affected by herbivory in the field.<br />Recent changes contributing to the increasing invasiveness of <em>E. annuus</em> might be (1) greater chance of winter survival at higher altitude due to climate warming, (2) summer drought, allowing the establishment and spread of <em>E. annuus</em> in grasslands, and (3) more plants escaping from slug damage once large populations have become established.</p> 2009-02-05T10:35:20Z tag:cis.danbif.dk,2009-02-05:/cooperation/fol195769/archive/lecture-limits-invasiveness-erigeron-annuus http://cis.danbif.dk/misc_/CHM2/Site.gif DanBIF Centre for Invasive Species