Mapping Invasive Plant Species with Hyperspectral Data Based on Iterative Accuracy Assessment Techniques

Recent developments in computer hardware made it possible to assess the viability of permutation-based approaches in image classification. Such approaches sample a reference dataset multiple times in order to train an arbitrary number of machine learning models while assessing their accuracy. So-called iterative accuracy assessment techniques or Monte-Carlo-based approaches can be a useful tool when it comes to assessment of algorithm/model performance but are lacking when it comes to actual image classification and map creation. Due to the multitude of models trained, one has to somehow reason which one of them, if any, should be used in the creation of a map. This poses an interesting challenge since there is a clear disconnect between algorithm assessment and the act of map creation. Our work shows one of the ways this disconnect can be bridged. We calculate how often a given pixel was classified as given class in all variations of a multitude of post-classification images delivered by models trained during the iterative assessment procedure. As a classification problem, a mapping of Calamagrostis epigejos, Rubus spp., Solidago spp. invasive plant species using three HySpex hyperspectral datasets collected in June, August and September was used. As a classification algorithm, the support vector machine approach was chosen, with training hyperparameters obtained using a grid search approach. The resulting maps obtained F1-scores ranging from 0.87 to 0.89 for Calamagrostis epigejos, 0.89 to 0.97 for Rubus spp. and 0.99 for Solidago spp.

Competition and Plant Trait Plasticity of Invasive (Wedelia trilobata) and Native Species (Wedelia chinensis, WC) under Nitrogen Enrichment and Flooding Condition

Nitrogen (N) is the important nutrition that regulatory plant functioning and environmental stability of invasive plant species under flooding (F) conditions. Little information clarifies the role of nitrogen enrichment and flooding on the invasive plant functional traits and competition with native competitors. Plant functional traits play an essential role in the successful growth of plants under different environmental conditions. Therefore, greenhouse pots experiment was conducted with invasive plant species (Wedelia trilobata, WT), and its native competitor (Wedelia chinensis, WC) in monoculture and cocultivation culture, along with flooding and nitrogen enrichment conditions. Considering the impact of flooding (F) and nitrogen (N) on an individual basis, the plant physiological traits of WC were nonsignificant compared to that of WT. However, in the combination of flooding × additional nitrogen (F.N, F.2N), plant physiological traits of WT were comparatively higher than those of WC, especially in cocultivation. In flooding × additional nitrogen (F.N and F.2N), better phenotypic plasticity at different plant traits makes WT more dominant in resource competition over WC. In conclusion, improved functional traits of WT under nitrogen enrichment and flooding conditions enhanced its competitiveness over native competitors.

The current status of the plant invasions in Belarus

This article provides a review of the current status of plant invasions in Belarus. As a result of this research into the alien flora between 2008 and 2020 a list of 52 invasive plant species that threaten biodiversity, human health, and economic has been compiled. About 300 taxa of non-native plants are currently classified as potentially invasive. The list of invasive plant species has been proposed in this article in accordance with trends in the invasive processes is the basis for the monitoring and management of plant invasions in Belarus. The preliminary data from the previous field seasons showed a significant increase in the population abundance and distribution of Swida alba, Rudbeckia laciniata and Artemisia abrotanum. Enrichment of the flora occurs due to the introduction of aggressive plants. Hybridization between native and alien plant species leads to the appearance of hybrids, which often have an invasive potential, and can invade not only disturbed habitats but also natural plant communities. The invasive properties, expansion, and aggressive behavior of these invasive plants of the alien flora of Belarus has led to significant, often irreversible, changes in the natural vegetation and vegetation cover. Invasive species such as Solidago canadensis, S. gigantea, Echynocystis lobata, Impatiens glandulifera are marked by rapid expansion over past decades, and Heracleum sosnowskyi, Solidago canadensis, S. gigantea, Echinocystis lobata, Impatiens parviflora, Acer negundo, Robinia pseudoacacia, Bidens frondosa, have invaded more recently.

Invasive alien plants in Poland – the state of research and the use of the results in practice

The participation of species of alien origin in the flora of individual regions of the world is increasing. A large proportion of these species pose a threat to biodiversity. Issues of the dynamics of changes in the flora and the scale and pace of the processes, with particular emphasis on the biology, ecology, chorology, and genetic variability of the populations of plants of alien origin, including those alien species which are invasive, have been the subject of many years of research in this field in Poland. The present study is an overview of the state of research on invasive plant species in Poland, including the main results of the basic and applied research which have provided the basis for (i) the preparation of a list of invasive plant species for Poland; (ii) assessing the degree of invasiveness of the species analysed, in accordance with the adoption of criteria and the development of methodological solutions. In this work, a new version of the list of invasive plant species has been prepared on the basis of earlier studies, combining theoretical and practical aspects of definition, and it is compared with the list of invasive alien plant species considered to constitute a threat to the EU and Poland as a member country. The categorization (risk assessment) of invasive alien species along with the identification of the most endangered types of natural habitats is often used in practice in the management of invasive plants in Poland. The results of our research have fed into the formulation of legal regulations at the global and regional levels.

FIRST FINDING OF SOLIDAGO × NIEDEREDERI IN TULA OBLAST (EUROPEAN PART OF RUSSIA)

Invasive plant species Solidago canadensis , widespread in Russia, occasionally forms hybrids S. × niederederi with the native species S. virgaurea . Previous findings of this hybrid were known mainly for the North-Western regions of Russia. Plants, morphologically similar to S. × niederederi, were found in August 2020 in the city of Aleksin in the Tula region. The hybrid origin of these plants was proved by the analysis of the nuclear ribosomal internal transcribed spacer 1-2 (ITS1-2). Analysis of the chloroplast non-coding intergenic spacer rpl 32- trn L showed that both parent species could act as both maternal and paternal ones in the same population. The available data suggest that individuals of S. × niederederi arise every time as a result of new hybridization events.