Editorial: Global Change, Clonal Growth, and Biological Invasions by Plants

Global changes in climate, land use, nutrient availability, acidity, populations of harvested or undesired species, and concentrations of toxins are now widely evident. Their ecological and evolutionary consequences are likely to be great but are often hard to identify or anticipate because of the multiple interactions that shape most ecological systems. One potentially important set of interactions involves the properties of clonal growth in plants. Clonal growth is common in plants and in ecosystems around the world and appears to be associated with the invasiveness of introduced plant species. Emergent clonal traits such as resource sharing and signaling between connected plants within clones, selective positioning of plants during clonal growth, stores of energy or nutrients that can be reallocated between connected plants, meristem banks that can be initiated in response to clonal integration, and tradeoffs between clonal and sexual reproduction might contribute to plant invasiveness and community invasibility, and global change may affect the expression, fitness effects, and evolution of these traits. This research topic assembles articles that deal explicitly with interactions between clonal growth and plant invasion or global change, and additional papers that advance understanding of aspects of clonal growth likely to affect invasion or response to global change. Four papers consider the evolution of clonality in plants. Epigenetic variation may provide an alternative means of adaptation to changing environments and play a key role during the invasion of some introduced clonal plants that cannot successfully reproduce sexually in the invaded range. In a forum paper, Dodd and Douhovnikoff propose how epigenetic variation may potentially enable clonal plants to adjust to changes in means and extremes of climate. Castro et al. report that plants of Oxalis pes-caprae from the native range show higher sexual fitness, while those from the invasive range have higher asexual fitness, suggesting that evolution has favored asexual over sexual reproduction during invasion. Roiloa et al. compare a different suite of clonal growth properties in Carpobrotus edulis from the native range in South Africa and the invaded range in Spain and Portugal. Plants from different ranges did not differ in degree of division of labor (i.e., specialization to acquire and share locally abundant resources), but the beneficial effect of clonal integration on the dry mass of apical ramets was higher in the introduced populations, suggesting that this clonal trait may have been selected for in the invaded range. Holmes et al. suggest that local adaptation …