Climate warming alters competition between two highly invasive alien plant species and dominant native competitors

Abstract

Biological invasions and climate warming are two major threats to the world's biodiversity. To date, their impacts have largely been considered independently, despite indications that climate warming may increase the success of many invasive alien species. We therefore set up an experiment to study competition between native and invasive alien plant species and the effects of climate warming thereon. Two highly invasive alien plant species in Belgium, each with a native competitor that dominated in invaded sites, were grown either together (1:1 mixtures) or in isolation (monocultures) at ambient and elevated temperature (+3°C) in climatecontrolled chambers. To detect possible mechanisms underlying the effects of competition and elevated temperature, we conducted a combined growth and nitrogen uptake analysis. In one pair, Senecio inaequidens -Plantago lanceolata (alien invasivenative), the alien species dominated in mixture, while in the other pair, Solidago gigantea -Epilobium hirsutum, the native species dominated. Climate warming reduced the invader dominance in the first species pair, but stimulated the suppressed invader in the latter. Many of the biomass responses for these two species pairs could be traced to the root-specific nitrogen uptake capacity. The responses of the native-invasive interaction to warming could not always be extrapolated from the monoculture responses, pointing to the necessity for experiments that take into account species interactions.

Comparative performance of the highly invasive Mimosa invisa and its less invasive subspecies under different nutrient and light conditions

“…inermis only under high nutrient and competitive conditions, which indicated that the results of the non‐competition experiment could not be extended to competitive conditions. Some previous studies also found that plant performance when grown alone does not predict performance under competitive conditions (Dawson et al ., 2012a; Verlinden et al ., ). However, these previous studies focused on the comparison between common and rare invasive species or between invasive and native plants.…”

“…Under the condition of low light, the biomass and ratio of root to shoot decreased significantly (Hou et al ., ; Huang et al ., ; Yasin et al ., ). Highly invasive plants may be more plastic than less invasive plants in some functional traits, which makes the highly invasive plants respond more positively to changes in environmental conditions and outperform the latter in at least some environments (Hastwell & Panetta, ; Richards et al ., ; Verlinden et al ., ).…”

“…In the field, a plant often grows in competition with neighbouring plants, and the performance of individual growth may not predict the performance in competitive environments (Dawson et al ., 2012a; Verlinden et al ., ). Several previous studies have shown that invasive plants outperformed natives only under competitive conditions (Verlinden et al ., ; Huang et al ., ).…”

“…In the field, a plant often grows in competition with neighbouring plants, and the performance of individual growth may not predict the performance in competitive environments (Dawson et al ., 2012a; Verlinden et al ., ). Several previous studies have shown that invasive plants outperformed natives only under competitive conditions (Verlinden et al ., ; Huang et al ., ). However, few studies have compared the performance of highly invasive and less invasive species under both competitive and isolated conditions (Dawson et al ., 2012a), and no such comparison has been made at the subspecies level.…”

Genetic variation and structure in native and invasive Solidago canadensis populations

“…Biological invasions pose serious threats to biodiversity and ecosystem functions at both global and local levels (Lövei, ). Nevertheless, they provide unanticipated opportunities for experiments to study ecological and evolutionary changes across large spatial and temporal scales (Sax et al ., ; Verlinden et al ., ). Analyses of genetic variation play an important role when studying biological invasions, because genetic variation is the raw material for adaptive evolution (Bossdorf et al ., ).…”