Assessment of Habitat Selection by Invasive Plants and Conditions with the Best Performance of Invasiveness Traits

Habitat selection is one of the fundamental concepts in ecology and means that each organism should choose the habitat that will maximize its success. Invaders may be an underestimated object in research on habitat selection. Invasive plants experience enormous propagule pressure and bear the costs of spreading in disturbed anthropogenic habitats. It means that they do not necessarily achieve maximum invasiveness traits in such habitats, which they selected to colonize. This study aimed to assess habitats where invaders are likely to occur from the set of all available ones in the landscape and the habitats with the best performed traits of invaders. The research was conducted on 52 and 112 plots in 2019 and 2021, respectively, in South-Eastern Poland, and the invasive plants were Caucasian hogweeds Heracleum sp. In the first year, the circle plots had a 50 m radius and were to measure habitat areas and traits of hogweeds (height, number of individuals in the plot, cover, and number of flowering specimens). Detrimental correspondence analysis and linear mixed model investigated that hogweeds achieved the best performance reflected by traits in continuous habitats—meadows and forests. In the second year, the plots to measure habitats had a 100 m radius. The reference plots were far from the invasion exposure, and the paired control vs. Heracleum ones had the same habitats with the potential to be invaded. The generalized linear mixed model showed that the probability of the hogweeds occurrence was higher when the habitat was overgrowing with a simultaneous decrease in open areas and in the increasing ruderal area with a decrease in bushes. The impact of the invader’s habitat on the invasion performance depended on the purpose of habitat selection. When invaders spread and increased invasive extent or appeared in habitat edges, they did not reach the highest traits, the best performing in continuous habitats. The specificity of habitat selection of invaders is another aspect that distinguishes invasion science from classic ecology.

Gridlock and beltways: the genetic context of urban invasions

The rapid expansion of urban land across the globe presents new and numerous opportunities for invasive species to spread and flourish. Ecologists historically rejected urban ecosystems as important environments for ecology and evolution research but are beginning to recognize the importance of these systems in shaping the biology of invasion. Urbanization can aid the introduction, establishment, and spread of invaders, and these processes have substantial consequences on native species and ecosystems. Therefore, it is valuable to understand how urban areas influence populations at all stages in the invasion process. Population genetic tools are essential to explore the driving forces of invasive species dispersal, connectivity, and adaptation within cities. In this review, we synthesize current research about the influence of urban landscapes on invasion genetics dynamics. We conclude that urban areas are not only points of entry for many invasive species, they also facilitate population establishment, are pools for genetic diversity, and provide corridors for further spread both within and out of cities. We recommend the continued use of genetic studies to inform invasive species management and to understand the underlying ecological and evolutionary processes governing successful invasion.

Environmental factors affecting the success of exotic plant invasion in a wildland-urban ecotone in temperate South America

Urbanization is one of the main causes driving changes in biodiversity patterns and it is regarded as a major threat to native biota. Successful exotic plant invasion depends on invasiveness and invasibility. Invasiveness is related to the characteristics of exotic plants and invasibility to the features of the sites. The objective of this study was to identify the invasibility environmental factors affecting the success of exotic plant invasion in a wildland-urban ecotone of the central region of Argentina (Potrero de los Funes Village, San Luis). Fifty phytosociological inventories were recorded in an area of 700 ha during spring and summer seasons (2013–2015). Abundance-coverage values of plants and environmental variables such as soil characteristics, anthropogenic disturbance, and altitude of the sites were assessed. Soil moisture, electrical conductivity (EC), acidity (pH), organic matter content, and nitrates were determined as part of the soil analysis. A Nonmetric Multidimensional Scaling analysis was used to identify the possible relationship between abundance-coverage of the vegetation and environmental variables. Abundance-coverage of exotic plants was positively influenced by anthropogenic disturbance and nitrate levels, and negatively affected by altitude. However, no significant correlation was found between percentage of exotic plants and pH, EC, or soil moisture. Thus, urbanization and touristic activities influenced the success of exotic plant invasion.