Linking concepts in the ecology and evolution of invasive plants: network analysis shows what has been most studied and identifies knowledge gaps

In recent decades, a growing number of studies have addressed connections between ecological and evolutionary concepts in biologic invasions. These connections may be crucial for understanding the processes underlying invaders’ success. However, the extent to which scientists have worked on the integration of the ecology and evolution of invasive plants is poorly documented, as few attempts have been made to evaluate these efforts in invasion biology research. Such analysis can facilitate recognize well-documented relationships and identify gaps in our knowledge. In this study, we used a network-based method for visualizing the connections between major aspects of ecology and evolution in the primary research literature. Using the family Poaceae as an example, we show that ecological concepts were more studied and better interconnected than were evolutionary concepts. Several possible connections were not documented at all, representing knowledge gaps between ecology and evolution of invaders. Among knowledge gaps, the concepts of plasticity, gene flow, epigenetics and human influence were particularly under-connected. We discuss five possible research avenues to better understand the relationships between ecology and evolution in the success of Poaceae, and of alien plants in general

Ecology of an invasive plant, Senecio inaequidens : interactions with pollinators, herbivores and soil fauna : comparison with the native Senecio jacobaea

Interactions with animals are thought to play a role in plant invasions, especially herbivores and pollinators. The importance of soil fauna in ecosystem processes is widely acknowledged and some invasive plants have been shown to affect their communities. In this thesis, field observations and experiments in natural or controlled conditions were conducted to investigate the interactions of these three faunic groups with the invasive Senecio inaequidens and the native related species, S. jacobaea. First, both plant species were visited by similar pollinator assemblages but S. inaequidens received more visitors per capitula than S. jacobaea. This difference could not be attributed to nectar or floral display. The reproductive success was higher for S. inaequidens than S. jacobaea, with 78 and 55% seed set respectively. The role of pollinators in seed set was not assessed but the difference between species may not be due to a higher self-fertility of S. inaequidens. Nevertheless, S. inaequidens had no impact on plant-pollinator interactions of S. jacobaea. Second, four out of the five studied herbivores attacked both S. inaequidens and S. jacobaea. The only herbivore restricted to S. jacobaea was the specialist caterpillar Tyria jacobaeae. Nevertheless, S. inaequidens was more impacted by overall herbivory than S. jacobaea, especially at the seedling stage by rabbit grazing. Pyrrolizidine alkaloids (main chemical defences) seem to play no role in the pattern of herbivore preferences. Third, soil arthropods were twice less abundant under S. inaequidens than S. jacobaea, essentially due to collembolan Arthropleona. No difference was found in the community assemblage but S. inaequidens was associated to higher arthropod diversity than S. jacobaea. These findings suggest that the two species interact with similar animal assemblages, but in different ways. The invasive success of S. inaequidens is more probably explained by an efficient reproduction than by a release from herbivores.Doctorat en sciences (sciences biologiques) (BIOL 3)--UCL, 200

Comparative study of the reproductive ecology of two co-occurring related plant species: The invasive Senecio inaequidens and the native Jacobaea vulgaris

Background and aims - A previous study showed that the visitation rate by pollinators and the seed set of the exotic invasive Senecio inaequidens (Asteraceae) were higher compared to the native relative, Jacobaea vulgaris. The first aim of the present study was to assess if these results could be explained by differences in self-fertility, nectar rewards or floral display between the two species. Moreover, in a second step, we examined if the higher visitation rate on S. inaequidens has a negative effect on the reproductive success of J. vulgaris. Methods - Self-fertility was estimated after self- and cross-hand pollinations. Nectar volume, total sugar concentration and sugar composition were analysed on plants cultivated under controlled conditions. In the field, in order to assess the effect of floral display and impact of the invasive on the pollination success of the native, insect behaviour was assessed by comparing visitation rates, number of visitors per 10 min observation and individual censuses. Floral display (density of capitula per unit area) was artificially modified by clipping or grouping inflorescences in both species. Key results - In terms of self-fertility, seed sets were similarly low after self-pollination (11-12%) for both species. S. inaequidens produced lower amounts of nectar with lower sugar concentration compared to J. vulgaris. No influence of floral display was detected on insect visitation rates. The presence of S. inaequidens did not alter pollinator visits and seed set of J. vulgaris. Conclusions - Other traits need to be investigated to explain the different visitation rates and reproductive success between the two species. The higher seed set of S. inaequidens could be due to a higher outcrossing rate, or more frequent pollinator movements between individuals. © 2011 National Botanic Garden of Belgium and Royal Botanical Society of Belgium.info:eu-repo/semantics/publishe

Soil arthropods associated to the invasive Senecio inaequidens compared to the native S. jacobaea (Asteraceae)

Belgian Biodiversity Platforminfo:eu-repo/semantics/publishe

Invasion biologiques un peu de vocabulaire

info:eu-repo/semantics/publishe

Les exotiques envahissantes en Belgique ont-elles des impacts ?

info:eu-repo/semantics/publishe