Kronenberger and colleagues 2025

Kronenberger JA, Wilcox TM, Schwartz MK. 2025. SmartScreen-AIS: A high-throughput qPCR chip for nationwide surveillance of aquatic invasive species. Environmental DNA 7(3): e70144. https://onlinelibrary.wiley.com/doi/abs/10.1002/edn3.70144

Abstract

 

Effective wildlife conservation requires frequent and widespread data on species occurrence. With the maturation of eDNA-based monitoring—now widely recognized as sensitive, cost effective, and legally defensible—nationally coordinated eDNA strategies are beginning to take shape. Such ambitious initiatives will require eDNA analytics with the throughput and sensitivity required for surveillance of many protected, pathogenic, and invasive species across broad geographic scales. Here, we help meet this need with SmartScreen-AIS: a high-throughput qPCR (HT-qPCR) chip with 46 assays targeting aquatic invasive species of widespread concern. SmartScreen-AIS was validated for use throughout the continental United States and can be subdivided into smaller chip formats as desired for use in specific regions or biomes. Assay performance in HT-qPCR was strong relative to conventional qPCR, with slightly lower specificity in some cases (due to pre-amplification) but significantly higher sensitivity. Contamination was rare, PCR inhibition was minimal to nonexistent, and demonstration at three military installations detected eDNA from all species on the chip that were known to be present and one species that was previously undocumented. Cost savings will depend on the number of assays used and samples tested, but in this study we estimate that eDNA analyses were 75% cheaper using HT-qPCR than they would be with our conventional qPCR protocol. To facilitate use, we provide appendices with assay details, bench protocols, a script for processing results, and an online app with state-level assay specificity information. SmartScreen-AIS has the potential to advance early detection of invasive species in the United States, and we hope our HT-qPCR workflow inspires chip development and use globally.

 

Keywords: None provided.

 

Keywords: 

Teesalu and colleages 2025

Teesalu P, Muuga JM, Hurt M, Kaldre K, Nõges T, Ercoli F. 2025. Effects of temperature on marbled crayfish (Procambarus virginalis, Lyko 2017) invasion ecology. Hydrobiologia: 852: 3541–3558. https://doi.org/10.1007/s10750-025-05828-y

Abstract

 

The marbled crayfish (Procambarus virginalis) is an invasive freshwater species spreading across Europe. Understanding its establishment and distribution is crucial, particularly in relation to temperature. This study examined the role of water temperature in marbled crayfish invasion in a warm outflow channel of a power plant in Estonia. We hypothesized that warmer water temperatures and the temperature gradient along the channel would influence crayfish establishment, distribution, and trophic niche. Temperature loggers revealed a distinct gradient, with the channel being warmer than the adjacent reservoir, providing a more suitable habitat for crayfish. Stable isotope analysis (¹³C and ¹⁵N) with MixSIAR and SIBER models showed distinct trophic niches along the channel: crayfish at the head of the channel consumed macroinvertebrates and macrophytes, while those at the mouth mainly consumed macroinvertebrates and periphyton. Additionally, crayfish shifted from eating primary consumers in spring and summer to primary producers in autumn. Water temperature was a key factor in crayfish establishment, but food availability also likely influenced their distribution. This study highlights the role of water temperature and ecological factors in the invasion dynamics of marbled crayfish, especially in the context of global warming.

 

Keywords: Stable isotopes • trophic niche • invasive species • population dynamic • temperature effect

Buřič and colleagues 2025

Buřič M, Ložek F, Görner T, Čuprová V, Kožený P, Mojžišová M, Vlach P, Štruncová E, Petrusek A, Kouba A, Svobodová J. 2025. Difficult to deal with: attempts for eradication of marbled crayfish from a small urban pond. Management of Biological Invasions 16(2): 443–464. https://doi.org/10.3391/mbi.2025.16.2.08

Abstract

The marbled crayfish is an emerging invasive species, mainly due to parthenogenetic reproduction and high adaptability. Its successful eradication seems to be possible only in early detected populations and under favourable conditions. The population of marbled crayfish was discovered in a small urban pond in Prague, Czech Republic, in August 2020. Shortly afterwards, management was initiated with the aim of complete eradication. The pond was harvested and drained twice in November 2020 and October 2021. The crayfish were collected, the exposed pond bottom was treated by liming and left dry over winter. Predatory fish were stocked in the pond after refilling. Survival of the crayfish after the pond draining in 2021 was likely facilitated by up to 40 cm deep burrows found under large boulders. No specimens were observed in the nearby stream and marbled crayfish presence was not detected by environmental DNA screening in the stream and three other standing waters in the vicinity. The combined efforts resulted in a reduction in crayfish densities by an order of magnitude between successive harvests, but complete eradication of marbled crayfish was not achieved by 2023, as individual juveniles were captured during monitoring in the following two years. The perch-dominated fish stock apparently exerts a strong predation pressure that may control the crayfish population, as no marbled crayfish were captured during monitoring in 2024. The current status of the population is unclear, and further monitoring is warranted. Effective cooperation between different institutions and stakeholders has been successfully established, and the public and stakeholders have been educated about the risks of invasive species. However, with prolonged activities aiming to eradicate the crayfish, we also experienced decrease of public support for further radical actions. This experience provides a solid basis for future invasive crayfish management activities at sites with similar conditions.

 

Keywords: invasive species • management • biological invasions • freshwater • crustacean • macroinvertebrates