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European freshwater ecosystems face a wide range of threats, and the introductions of non-native species are major drivers of biodiversity loss. Amphipod crustaceans (from the Gammaroidea family), are a particularly damaging group and have been highly successful at establishing, spreading and exerting major impacts in novel habitats.

One recent study led by James Dickey, a researcher from the Invasion Biology Division of the National Laboratory of Health Security of Hungary, James Dickey focused on Gammarus tigrinus, a species native to the brackish tidal estuaries along North America’s Atlantic coast, which has established in freshwater systems across Europe. As well as exerting negative impacts on native biodiversity, it has led to socio-economic costs to fishermen through damaged fishing gear and injured catches. Interference competition with native species – where individuals interact, often aggressively, to prevent access to a resource – is just one of many impacts the species exerts, but this has received limited study to date. In this study the authors staged dyadic contests, pitting the North American amphipod against the native European Gammarus duebeni in a battle over an insect larva as a single food resource. The invasive gammerid was found to secure the prey faster and defend it more strongly than the native. Further, they exhibited more aggressive interactions and activity levels with increasing size and mass, whereas larger G. duebeni were shown to be less aggressive and less active. The non-native was also less thigmotactic, or “bolder”, being more explorative and spending a smaller proportion of time in the outer zone of the arena.

James Dickey hopes to develop this method further, applying it to a number of non-native ampipods from the Ponto-Caspian region. This is a notorious donor hotspot for invasive species, many of which have established in the Danube. “The Danube is a dream study system for an invasion ecologist, acting as a conveyor belt for non-native species across Europe. Learning more about the impacts posed by species that have established here in Hungary can help inform prevention and management elsewhere in Europe.” Currently setting up a lab and collaborating closely with András Abonyi and Péter Borza of the Lendület Fluvial Ecology Research Group at HUN-REN CER, Dickey will focus on Dikerogammarus bispinosus (pictured) and the notorious “killer shrimp”, D. villosus, determining how their behaviours drive impacts and how these might change in the future under climate change and other anthropogenic stressors.

We are pleased to announce that our researchers participated in the 22nd National Conference of the Association of Hungarian Pest Control Operators, which was held in Tapolca, Hungary this year. The event provided us with a great opportunity to present the results of the Mosquito Monitor project so far and to establish valuable professional relationships with companies and organisations responsible for mosquito control in Hungary.

During the conference, we also attended several exciting and informative presentations that provided inspiration for our future work. By exchanging experiences and building relations, we can contribute to the planning and implementation of a more effective and more eco-conscious mosquito control strategy.

In addition to its many direct negative effects, fragmentation of natural habitats can also facilitate the establishment and spread of invasive plants, which can further damage native wildlife. However, the exact nature of these effects may vary depending on the habitats affected and the group of organisms being studied. Most of the information we have are limited to native plants, yet the changes caused in arthropod communities are poorly understood. Therefore, we investigated the impacts of fragmentation and the presence of milkweed, which is a major conservation problem in the Great Hungarian Plain, on invertebrate communities in sandy grasslands of forest-steppe habitats.

In total, we surveyed pollinators (wild bees) and collected ground-dwelling arthropods, mainly herbivores (true bugs) and predators (spiders), and examined their characteristics in 60 habitat patches. We demonstrated the interaction between the effects of fragmentation and invasion, which usually modify and can strengthen each other’s effects. Milkweed has a stronger direct impact on herbivorous bugs and pollinators, while it affects ground-dwelling spiders only indirectly. The interaction between fragmentation, invasion and the conservation of biodiversity is very complex, and continuous monitoring and the use of adaptive management techniques are essential for its effective management.

Climate change and biological invasions are two of the most significant challenges facing ecological restoration efforts today. In the sand grasslands of Hungary, these pressures interact in complex ways, affecting how restored ecosystems develop over time. Researchers from the HUN-REN Centre for Ecological Research, Invasion Biology Division of the National Laboratory of Health Security, conducted a long-term study to understand how drought severity and restorative mowing influence the recovery and vulnerability of sand grassland ecosystems.

The research focused on three locations within the Kiskunság region, where invasive black locust stands (Robinia pseudoacacia) were removed between 1994 and 1995, and regular mowing was applied until 2001 to prevent regrowth. Using comprehensive vegetation data collected from 1995 to 2019, alongside long-term weather data, the team analysed the dynamics of native target species, invasive species, and drought-tolerant C4 plants under changing drought conditions.

The findings reveal that native sand grassland species demonstrated notable resistance to drought, maintaining stable populations even as summer droughts became more frequent and severe. In contrast, invasive species tended to decline during severe droughts, while C4 species, which are more tolerant of heat and dryness, became more dominant. Although mowing — commonly used to aid grassland restoration — effectively prevented the reinvasion of the targeted black locust, it did not enhance the recovery of native sand grassland species. Instead, it facilitated the spread of invasive herbaceous species, particularly under drought conditions. This unintended consequence highlights the complexity of restoration practices: interventions that control one problem may inadvertently create new vulnerabilities. In fragmented landscapes, where nearby habitats serve as reservoirs for invasive species, this risk is even greater.

The study emphasises that sand grasslands are naturally resilient to many disturbances, but their long-term stability depends on considering multiple ecological factors. Restoration strategies must go beyond local-level interventions and should consider landscape-scale dynamics and climatic impacts. The research underscores the need for adaptive, flexible restoration practices that anticipate future climatic stresses and invasion risks. It also highlights the importance of frequent, long-term monitoring to capture the delayed and sometimes subtle responses of ecosystems to environmental change.

The raccoon is one of the most widespread invasive mammal species in Europe. Its expansion on the continent dates back to 1934, when the first few individuals were released in Germany. Since then, their numbers have grown to several hundred thousand, and they are becoming increasingly common in many other European countries, including Hungary.

The 3^rd EURORACCOON Meeting was recently held, where raccoon researchers presented their latest work and discussed the management of the species. Three of us from the Hungarian University of Agriculture and Life Sciences participated in the event and gave presentations about our work in the Invasion Biology Division of the National Laboratory for Health Security, Hungary. We presented the raccoon wildlife camera trap studies, which confirmed the nest predation effect of the species, and described the annual occurrence of raccoons in their most important habitat in Hungary; our results on the condition and reproductive biology of raccoons in Hungary; and the experiences of the first local eradication program of the country, implemented for the species.

The conference took place at the Seminarzentrum Edersee event venue in the Kellerwald-Edersee National Park, Germany – at the historic site where the raccoon’s European conquest began.

During the three-day event, in addition to the professional activities, the researchers visited natural habitats, including a primeval beech forest, where raccoons are becoming an increasingly significant part of the ecological community, and also took an evening raccoon-watching tour in the nearby “raccoon capital” of Kassel, where they witnessed the species in large numbers and discussed their management in the city. For those who were up to some culinary adventures, the program was also enriched with a “raccoon barbecue”.

One of the important findings of the meeting was that although the raccoon is an extremely successful predator with a diverse diet and can also spread infections, there is hardly any research that would prove its actual significant impact. Therefore, there is a great need for such targeted research. In some places, the complete eradication of the species seems hopeless, but its spread to areas not yet occupied can be prevented. In Hungary, its population could still be kept under control with well-organized interventions.

Participants of the event would like to see next year’s conference on the Gödöllő Campus of the Hungarian University of Agriculture and Life Sciences, in Hungary.

Participants from the Division of Invasion Biology of NLHS: Dr. Krisztián Katona, Dr. Zsolt Biró, Balázs Bócsi

The “first of its kind” conference in Hungary enabled nationwide and international discussion on invasive alien species – a cohesive action plan is finally on the horizon

The conference took place in Sarlóspuszta, Hungary between 26 and 28 February 2025, organised by the HUN-REN Centre for Ecological Research and the Invasion Biology Division of NLHS. It was aimed to foster knowledge exchange and proactivity among researchers, practitioners, and policymakers on managing invasive species through the interdisciplinary “One Biosecurity” framework. This approach integrates plant, animal, human, and environmental health to mitigate the impacts of biological invasions.

On the first day, the “One Biosecurity” concept was introduced by the day’s plenary speaker, Dr. Philip Hulme, a distinguished professor of plant biosecurity at Lincoln University, New Zealand. He highlighted its potential to unify decision-making across sectors for better biosecurity outcomes while emphasizing its holistic approach to biosecurity threats. Speakers of the day presented their studies on such threats imposed by human, animal and plant parasites and their vectors, such as alien mosquito species and their spread diseases or fungal diseases of plants, as well as invasive species with a high risk to native animals and environmental health, i.e., the raccoon and the raccoon dog, or released exotic pet fish and reptile species.

The second day featured scientific presentations on invasion biology topics such as spread mechanisms, monitoring and control, ecological roles, and socio-economic impacts. Dr. Petr Pyšek, a senior research scientist at the Czech Academy of Sciences, and Dr. Piero Genovesi, chair at the IUCN SSC Invasive Species Specialist Group, delivered plenary talks on cutting-edge research and control methods. Dr. Petr Pyšek’s presentation focused on mechanisms of species invasiveness and global biogeography of alien floras. Whereas Dr. Piero Genovesi discussed strategies for controlling invasive species and related policymaking. Some of the highlights from other speakers were mapping the spread of invasive plant species and using AI technology for maximising efficiency; unintentional dispersal of plant seeds; targeted control of invasive trees; biological control of insect pests; the control issues with the coypu and alien aquatic macrofauna, the damage they cause, and the potential to reduce the impact of invasive fish with the reintroduction of beavers.

Finally, the third day was comprised of a day-long workshop that facilitated collaboration between researchers and practitioners from various fields, focusing on co-producing actionable knowledge for managing invasive species effectively. One of their conclusions was that involving and helping the lay public in reporting and managing invasions is as important as cooperating with farmers, foresters, gardeners, and other related professionals. Understanding and mitigating the spread of alien species requires a combined effort from all layers of society, and finding the appropriate channels of communication to each layer is a key factor in doing so.

In summary, the conference emphasized the importance of prioritising invasive species management efforts on high-risk, early-stage invasions. Geographic context was highlighted as crucial, with island nations better focusing on border controls and mainland countries with open borders, like Hungary, are advised to prioritise nationwide monitoring focusing on high-risk hubs of travel and trade. Key recommendations included legislative improvements, increased government support and investment, multi-stakeholder and sectorial collaboration, education on biosecurity in schools, and the use of clear terminology in media.

A key conference goal was translating the One Biosecurity concept into Hungarian to ensure effective communication through media channels. The result is “ökobiztonság” which translates to “Eco-Security” in English – a much more widely understood term in Hungarian that, with the right contextualisation, can also cover the unified concept of the protection of plant, animal, human, and environmental health.

Book of Abstracts »
One Biosecurity workshop, Mentimeter results »

The loss of biodiversity on our planet is partly due to the presence and spread of alien invasive species. Once an invasive species has established in a new habitat, it can alter the structure and function of the ecosystem to such an extent that it has an impact even after removal, making it very difficult to control and eradicate. Ecological restoration, when carried out in an effective and sustainable way, contributes to biodiversity conservation and climate change mitigation, resilience and adaptation, and has proven to be an effective method of controlling invasive species. At the same time, the presence of invasive species in the landscape can compromise restoration objectives. The aim of this study is to assess how the abundance of annual and perennial invasive species varies with location, direction and distance around the restoration site, and which factors should be considered when planning restoration interventions.

Seeds of plant species are often dispersed unintentionally on our clothes, which thanks to the increasing mobility of people, can be important events in the process of biological invasions. Researchers from the HUN-REN Centre for Ecological Research, ‘Lendület’ Seed Ecology Research Group, investigated this topic, and published their results in the D1-ranked scientific journal Journal of Environmental Management. This study provides critical insights into the unintentional spread of plant species through human-vectored dispersal via clothing, a pathway that has received limited attention so far. Their findings show that most seeds remain viable after typical household washing, even at common temperatures and a wide range of detergent types, highlighting a largely overlooked vector of plant dispersal. Since most of the plants that are capable of cloth-dispersal are weeds and invasive species, the results have important implications for invasion control. They emphasize the need for targeted biosecurity measures, especially among those working outdoors, to mitigate the spread of invasive species. The results also offer actionable strategies for environmental management by integrating behavioural changes and public awareness to reduce the environmental impact of human-vectored dispersal. According to their questionnaire survey, raising awareness is especially important for nature conservation professionals who are among the most important potential vectors.

Citation of the paper:

Lukács, K., Kiss, R., Tóth, Á., Godó, L., Deák, B., Valkó, O. (2025): Effects of laundry washing on germination of cloth-dispersed seeds depends on washing intensity not on detergent type. Journal of Environmental Management 375: 124345.

Invasive mosquito species already established in Hungary can pose a significant threat to human and animal health due to their potential role in the pathogen transmission. Researchers from the HUN-REN Ecological Research Centre and the University of Pécs, part of the Invasion Biology Division of the National Laboratory for Health Security, and ELTE have published their results in the D1-ranked scientific journal ‘Journal of Pest Science’. In this study the researchers evaluated the effect of environmental factors reflecting climate, habitat type, food supply, traffic, and interspecific competition on the distribution of three invasive tiger mosquito species in Hungary. They trained species distribution models using citizen science observations and then predicted the potential distribution of the species. The researchers uncovered species-specific patterns and found that different predictor sets were selected for the three different species, however, only predictions for Asian tiger mosquito could be validated with direct trapping data. They concluded that citizen science informed distribution maps can be used to identify environmental predictors that determine the spread of invasive mosquitoes.

Researchers of the National Laboratory for Health Security’s Mosquito Monitor program created a new laboratory to breed invasive mosquitoes and to study their acoustic ecology. Adult individuals of the tiger mosquito (Aedes albopictus), which is bred here, feed on nectar in the wild, but get sugar-water instead in the lab. In order to produce eggs, females are fed with sterile cow blood via the Hemotek system, a device designed specifically for feeding blood sucking insects. The lab follows the arthropod containment guidelines, in order to prevent any potential escapes.

The researchers built a soundproof box with camera and microphones inside, with which they are able to record high quality footage even of low sound intensity. Audio recordings can be analysed using a specialised software, thus several acoustic variables can be extracted. The variation in sound can also be linked to the mosquito behaviour, recorded using the video camera.

Two projects are currently running in the lab. The first one is the identification of mosquito species based on sound, with the help of artificial intelligence. The second project aims to better understand the acoustic communication of the female and male tiger mosquitoes during the mating sequence. In some other mosquito species it has been shown that the male and female converge toward the same sound frequency right before mating together. This capacity of changing the flying sound and to adjust to the potential mate could play a significant role in mate choice and sexual selection. A better understanding of this phenomenon could help develop efficient techniques in mosquito control.