Naturalization and impact of a horticultural species, Cotoneaster horizontalis (Rosaceae) in biodiversity hotspots in Belgium

peer reviewedCultivation of ornamental plant species has been recognized to foster plant naturalization of exotics by counteracting environmental stochasticity and continuously providing propagules. As a preliminary attempt to describe the invasion status of C horizontalis, we gathered information on the occurrence of the species in Belgium by compiling various databases. We assessed the naturalization status of C. horizontalis in Belgian calcareous grasslands, high-value habitats recognized as biodiversity hotspots, by characterizing its occurrence, population status, preferred habitats, invaded communities, growth rate and fruiting capacity. We also assessed the impact of the species on calcareous grasslands communities and on individual species. Cotoneaster occurred in seven of the nine investigated sites, with densities varying from 0.34 to 10 individuals/ha. In the most invaded sites, the high proportion of small individuals suggests an important ongoing colonization process, emphasized by the fact that fruiting capacities were demonstrated for 3-year-old individuals. Invaded habitats were typically Mosan Xerobromion habitats, which are priority Natura 2000 habitats. The presence of C horizontalis was associated with changes in both the structure and composition of the community by decreasing species richness and diversity, and affecting grassland specialist species. These impacts are expected to intensify over time with population age and increasing propagule pressure due to close urbanization

Hybridization And Sexual Reproduction In The Invasive Alien Fallopia (Polygonaceae) Complex In Belgium

peer reviewed† Background and Aims The knotweed complex, Fallopia spp. (Polygonaceae), belongs to the most troublesome invasive species in Europe and North America. Vegetative regeneration is widely recognized as the main mode of reproduction in the adventive regions. However, the contribution of sexual reproduction to the success of these invasive species has only been detailed for the British Isles. An examination was made as to how hybridization may influence the sexual reproduction of the complex in Belgium and to determine how it may contribute to the dispersal of the species. † Methods Studies were made of floral biology, reproductive success, seed rain, seed bank, germination capacity, seedling survival and dispersal capacity in order to characterize the reproductive biology of the species. Moreover, chromosome counts and flow cytometry were used to assess the hybrid status of seedlings produced by sexual reproduction. † Key Results In the area investigated, extensive sexual reproduction by hybridization within the complex, including one horticultural species, was demonstrated. A small percentage of seeds may be dispersed outside the maternal clone (.16 m) allowing the formation of genetically differentiated individuals. Seed germination was possible even after a winter cold period. †Conclusions The extensive sexual reproduction by hybridization could further contribute to the dramatic invasive success of knotweeds in Belgium and should not be underestimated when considering control and management measures

Occurrence cubes : a new paradigm for aggregating species occurrence data

In this paper we describe a method of aggregating species occurrence data into what we coined “occurrence cubes”. The aggregated data can be perceived as a cube with three dimensions - taxonomic, temporal and geographic - and takes into account the spatial uncertainty of each occurrence. The aggregation level of each of the three dimensions can be adapted to the scope. Built on Open Science principles, the method is easily automated and reproducible, and can be used for species trend indicators, maps and distribution models. We are using the method to aggregate species occurrence data for Europe per taxon, year and 1km2 European reference grid, to feed indicators and risk mapping/modelling for the Tracking Invasive Alien Species (TrIAS) project

Ecology and evolution of invasive plants: what to study next?

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

The impact of aquatic alien plants and crayfish control methods on ecosystem services

editorial reviewedAn increasing number of field managers are engaged in actions aiming at controlling invasive species, notably in aquatic and riparian ecosystems. Though, control actions may influence how ecosystems function and provide services to humans. When faced with the choice of which control method to use, managers and decision makers typically consider the cost, feasibility or effectiveness of methods. More rarely do they consider the impact that the intervention will have on ecosystem functioning and services. This consideration is one of the focal points of the LIFE RIPARIAS project (2021-2027). Ecosystem Services (ES) evaluation typically relies on a matrix relating ES to ecosystem types. We developed a conceptual framework based on adapted ES matrices and ran a comprehensive literature review of the control methods for EU-listed aquatic plants, riparian plants and crayfish. The results of the review were screened by experts and stakeholders in order to select best practices for each species. A one-day workshop was hold with experts and stakeholders to identify the relevant ES in this context, challenge our conceptual framework and prepare an online survey. On the basis of this expert consultation, we evaluated ES evolution for each control method, considered for two different time scales: one year and five years after the intervention. The evaluation was relatively consensual among experts from different countries. The results showed that whatever the species group, the choice of a control method may influence provisioning, regulation and cultural services. When control methods had negative impacts on ecosystem services (notably for aquatic plants), the influence was typically highest after one year. Despite the inherent subjectivity of expert-based assessment, the present study illustrates how a comprehensive ES evaluation can be useful to support managers in selecting most appropriate control options

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

TrIAS : Publishing and analysing biodiversity data rapidly, repeatably and FAIR-ly for agile policy relevant results

Informing policy on invasive species requires rapid mobilization of biodiversity data from many sources and converting these raw data into simple metrics and reliable information. Yet the data are collected by a wide variety of actors, both professional and amateur, and they are often divided by political and language barriers. Belgium is typical in that sense, we struggle with the fragmented data sources and restrictions on data mobility, while trying to answer the policy needs at both national and local levels. In 2017 we launched the TrIAS project that aims to resolve some of these problems. We envisage a future where data are rapidly mobilized, the spread of exotic species is regularly monitored, future risks are evaluated and potential impacts assessed [1]. In many ways we have similar aims to GFBio, though we may have found different solutions to the same problems. TrIAS is building workflows that openly publish species information and primary biodiversity data, then harvest those and other data, to create indicators, predictive models and policy support documentation. TrIAS is a consortium of 12 Belgian institutions together with another 9 stakeholder organizations. We aim to address terrestrial, freshwater and marine environments. The organizations involved include those involved in citizen science, pure and applied research, and wildlife management. TrIAS is an open science project; all the software are shared under an MIT Licence; all the data are shared under a CC0 licence waiver and all the documentation is shared under Creative Commons licenses. The hope is that this approach will contribute to the post-project sustainability, because the data and software can all be reused as a whole or in part, either in Belgium, or anywhere else it is needed. Such reuse need not be confined to alien species monitoring, but there is also a need for repeatability and rapid mobilization in other fields, such as red-listing of conservation worthy species. KEYWORDS: invasive species, rapid data publication, sustainability, biodiversity monitoring, cost-effective, Global Biodiversity Information Facility, R tools, controlled vocabularies, policy relevant REFERENCES: 1. Vanderhoeven, S., Adriaens, T., Desmet, P., Strubbe, D., Backeljau, T., Barbier, Y., Brosens, D., Cigar, J., Coupremanne, M., De Troch, R., Eggermont, H., Heughebaert, A., Hostens, K., Huybrechts, P., Jacquemart, A., Lens, L., Monty, A., Paquet, J., Prévot, C., Robertson, T., Termonia, P., Van De Kerchove, R., Van Hoey, G., Van Schaeybroeck, B., Vercayie, D., Verleye, T., Welby, S., Groom, Q. 2017. Tracking Invasive Alien Species (TrIAS): Building a data-driven framework to inform policy. Research Ideas and Outcomes. 3, e13414. https://doi.org/10.3897/rio.3.e1341