1. Above: Presentation by Quentin Groom - A better understanding of species interactions would reveal the impacts of invasive species.

If you look at the main causes of invasive species impacts they mostly consist of the interactions with other species. For example, impacts such as predation, parasitism and competition all involve interactions of one species with another. Indeed every organism has interactions with other organisms, some are very specific, such as obligate parasites, others much more general. In the non-native range of an invasive species these interactions may be similar to their interactions in their home range or completely novel. It is therefore important to collect data on which species interact, how they interact, when they interact and the degree to which they interact. With these data one might be able to predict impacts of invasive species in a novel environment and you might better understand if an invader has suitable habitat in an area.

Species interactions occur all the time, but are often very brief, such as flower visitations. It is difficult to collect these data, particularly if you do not know where they will occur. A possible source of data might be citizen scientists. Yet citizen science projects have traditionally focused on observing single species groups such as birds, butterflies and plants, rather their behaviour and interactions. In this webinar we will discuss the use of interaction data for understanding  invasive species impacts and we can use the opportunity to discuss improving citizen science projects to collect these data.


2. Above: Presentation by Núria Roura Pascual - Alternative futures for global biological invasions.

Scenario analysis has emerged as a key tool to analyze complex and uncertain future ecological developments. However, global scenarios have neglected biological invasions, and their interactions with socio-economic and environmental developments. We used a multidisciplinary participatory process to develop new global biological invasion scenarios (narratives of how the world may develop) spanning a wide breadth of plausible global futures through 2050. We identified drivers expected to influence invasions, organized them into political, socio-economic, cultural, technological, and ecological categories. We adapted the widely-used “two axes” scenario analysis approach to develop four families of four scenarios each, resulting in 16 scenarios. Our scenarios underscored that information related to socio-economic developments and sustainability policies and lifestyle could play a crucial role in shaping biological invasions, along with well-known ecological drivers of biological invasions, such as climate change and human footprint. Our scenarios align fairly well with existing environmental scenarios and the recently development shared socio-economic pathways, although we explored a series of futures underrepresented from existing climate-oriented scenario narratives. These constructs are crucial to facilitate the incorporation of biological invasions within global environmental assessments.

Publication: Roura-Pascual N, Leung B, Rabitsch W, Rutting L, Vervoort J, Bacher S, Dullinger S, Erb K-H, Jeschke JM, Katsanevakis S, Kühn I, Lenzner B, Liebhold AM, Obersteiner M, Pauchard A, Peterson GD, Roy HE, Seebens H, Winter M, Burgman MA, Genovesi P, Hulme PE, Keller RP, Latombe G, McGeoch MA, Ruiz GM, Scalera R, Springborn MR, von Holle B, Essl F (Under revision) Alternative futures for biological invasions. Sustainability Science.


3. Above: Presentation by Periklis Kleitou - Fishery reforms for the management of non-indigenous species

Marine ecosystems are undergoing major transformations due to the establishment and spread of Non-Indigenous Species (NIS). Some of these organisms have adverse effects, for example by reducing biodiversity and causing ecosystem shifts. Others have upsides, such as benefits to fisheries or replacing lost ecological functions and strengthening biogenic complexity. Stopping the spread of NIS is virtually impossible in the Mediterranean Sea, the world’s most invaded marine region. The societal challenge is how to limit the socioeconomic, health, and ecological risks, and sustainably exploit the benefits provided by these organisms. We propose a move away from the notion that NIS have only negative effects, and suggest a turn towards an Ecosystem-Based Fishery Management approach for NIS (EBFM-NIS) where species are managed depending on the range of costs and benefits to ecosystems, ecosystem services, and fisheries. 

Publication: Kleitou, P., Crocetta, F., Giakoumi, S., Giovos, I., Hall-Spencer, J. M., Kalogirou, S., ... & Rees, S. (2021). Fishery reforms for the management of non-indigenous species. Journal of Environmental Management, 280, 111690. 



4. Above: Presentation by Elizabete Marchante - Biological control of invasive plants in Europe: the case study of an Australian gall-wasp in Portugal and how citizen science can help

With FA López-Núñez, R Heleno, LN Duarte, J Palhas, F Impson, H Freitas, H Marchante

Classical biological control may be important for the successful management of invasive alien plants, but it is relatively new in Europe. The few examples in Europe will be presented followed by the case study of the biocontrol agent Trichilogaster acaciaelongifoliae (an Australian gall-wasp) recently released in Portugal against Acacia longifolia. Since 2015, we have monitored the establishment, spread and early impacts of this agent on the target-plant, across the Portuguese coast. The impacts on the reproductive output and vegetative growth of A. longifolia were evaluated in more detail at three study sites. By 2020, there was establishment confirmed in 36 sites and galled A. longifolia branches were producing significantly less pods, seeds and secondary branches and also producing less phyllodes.

After an modest initial establishment, T. acaciaelongifoliae adapted to the northern hemisphere conditions and there was an exponential increase in the number of galls and the area of establishment increased significantly, making it difficult to monitor all areas. Therefore, since 2020, we have been asking citizens to help us locate and count the galls of T. acaciaelongifoliae, assisting not only in monitoring this agent, but at the same time raising awareness about biological control and invasive species.

Based on:

López-Núñez, F.A., Marchante, E., Heleno, R., Duarte, L., Palhas, J., Impson, F., Freitas, H., Marchante, H. Establishment, spread and early impacts of the first biocontrol agent against an invasive plant in continental Europe. Accepted for publication in the Journal of Environmental Management.