Abstract. To capture the complexity of fungal communities, microbial ecologists must often resort to amplicon sequencing. Amplicon sequences are obtained from the nuclear ribosomal internal transcribed spacer (ITS), which is currently used as a marker for fungal taxonomic identity. Raw amplicon sequences are analysed using either amplicon sequence variants (ASVs) or operational taxonomic units (OTUs). However, these two approaches are conceptually different, and there is disagreement over which is more suitable for fungal sequence data. In order to address this problem, we used published fungal genomes to simulate amplicon sequencing of the ITS1 and ITS2 regions of fungal communities with diversity spanning 50 to 800 strains. These data were then analysed via six pipelines with differences at key steps in read processing and ASV/OTU retrieval. In addition, we confirmed the results with sequencing data from a previously published 189-strain mock community. Our results show that the choice between ASV and OTU has only a minor effect on the end result and that the most important step in the analysis pipeline is the extraction of the ITS region from the short-read sequences. Moreover, we recommend sequencing with as large a library size as possible, joining the reads to perform ITS extraction and then clustering the sequences into OTUs. We hope that this will help microbial ecologists choose the most appropriate approach to answer their specific questions.

Abstract. Urban soil plays a fundamental role in supporting a range of ecosystem services important for both human health and urban resilience. While many ecosystem services rely on soil microbial communities, studies on urban soil microbes have remained scarce. A major complexity in understanding urban soil bacteria is the heterogeneity of soil throughout the city. In this study, we investigated the urban soil bacterial communities of street tree areas in relation to soil characteristics. We sampled soils under London plane trees at 20 street sites throughout the city of Antwerp (Belgium) and looked into the horizontal and vertical spatial variation in soil bacterial communities. Using 16S rRNA gene amplicon sequencing, we found great bacterial diversity (over 1800 bacterial genera) and heterogeneity in the urban soil of a single city. Our findings suggest that, first and foremost, urban soil community variation is determined by the sampling site, indicating that samples grouped together in space are more similar. Additionally, but to a smaller extent, the bacterial communities are affected by soil characteristics as is the case for non-urban soils. Significant relationships were observed between composition and soil pH, moisture, density, depth, air pollution, and land use class (all p values < 0.01). We found that soils, especially those with relatively low moisture content in the city under study, showed a decline in soil bacterial biodiversity with decreasing moisture content (p value = 0.047), indicating that soil moisture content may be an important aspect of sustainable urban soil management. Furthermore, soils under trees with a smaller circumference varied greatly in bacterial community composition relative to soils under trees with a bigger circumference, which were significantly more alike in bacterial composition. This indicates that, to better predict urban resilience, factors such as soil and vegetation development should be taken into account. In conclusion, we recommend including microbial soil diversity in urban sustainable soil management and focusing future urban soil research on understanding what the desired microbial functions and compositions for urban soils are.

Abstract. Global nutrient cycles (biogeochemical flows of nitrogen and phosphorus; N, P) are at a tipping point. In aquatic systems, natural food webs facilitate nutrient digestion and decomposition, but nutrient assimilation is poor. The current approach to understanding and managing nutrient cycles in aquatic systems needs to integrate animal nutritionist thinking. It is not the supply or stoichiometry of elements (carbon (C), N, P) in the food web but the supply and stoichiometry of specific biomolecular packages in which they come (aka Rings of Power) that decides the state of nutrient cycles (slow/fast, low/high) in all trophic levels above primary producers. Animal nutritionists often maximize N and P retention efficiency in animal production systems by expanding the scope of homeostatic control of nutrient deposition in animals. By spiking specific biomolecular packages in the diet (e.g., Rings of Power, such as specific amino acids, lipid classes, carbohydrate subfractions like starch), it is possible to alleviate energy–nutrient transfer barriers from food to biomass. Under the influence of “Rings of Power”, free N and P excretion is minimized and protein (N-bound), phospholipid, and apatite-rich (P-bound) biomass is maximized. Combining such expertise with food web (plankton) ecology, we can develop nature-based, regenerative aquaculture solutions in hypertrophic inland standing waterbodies (which accumulate nutrients) to slow down N and P cycles by curbing the metabolic N and P throughput of consumer communities (omnivorous fish, zooplankton) and suppress eutrophication.

Abstract. Background and aims: Extreme environments (polar, alpine, arid) are frontiers of global change, where the interaction between plants and soil biota dictates ecosystem resilience. Soil nematodes are critical components of the soil food web, mediating nutrient cycling. This review synthesizes current understanding of nematode ecology across these systems, focusing on adaptive strategies, biogeographic patterns, and climate change responses. Scope: We combine research from around the world on soil nematodes from polar, alpine, and dry areas. We examine their adaptive strategies, what causes their community structure, and how they respond to climate change. Results: Soil nematode survival is underpinned by convergent adaptations, notably cryptobiosis and opportunistic life histories. While liquid water availability is a universal constraint, biogeographical patterns are shaped by system-specific drivers: temperature thresholds in cold environments and moisture pulses in deserts. Our synthesis reveals that local soil properties and, where present, vegetation patches (e.g., biocrusts, plant rhizospheres) create crucial micro-refugia, often overriding macroclimatic controls. Climate change impacts are primarily indirect; for instance, warming affects nematodes by altering permafrost stability and meltwater regimes in polar regions or by inducing uphill shifts in plant communities in alpine zones, creating mismatches between migrating nematodes and soil development. Conclusions: Soil nematode communities in extreme environments are highly sensitive indicators of climate change, responding to shifts in both abiotic and biotic conditions. Understanding their adaptive limitations and the response pathways is critical for predicting the future of nutrient cycling and the stability of communities in Earth's most vulnerable ecosystems. Future research should focus on the multi-faceted interactions between plants, microbes, and nematodes under combined global change stressors.

Abstract. Climate change may reduce available habitat for native species, while simultaneously increasing suitable habitat for invasive species, which then compete with or predate on native species. Thus, climate change and invasive species can interact synergistically to negatively affect native species. It is important to identify climate refugia that are likely to be both suitable for native species and unsuitable for invasive species, under both present and future climate conditions. We propose a refugia habitat metric (RHM) based on ecological niche modelling. We demonstrate the utility of the metric via a case study of an endemic freshwater crayfish, or kōura (Paranephrops planifrons), which is threatened by both climate change and predation from the invasive brown bullhead catfish (Ameiurus nebulosus) in Aotearoa / New Zealand. We used maximum entropy (MaxEnt) ecological niche models to predict current and future habitat suitability for the two species across Aotearoa / New Zealand. By the period 2080–2100, suitable habitat will increase across the northern and western North Island for catfish, while suitable habitat for kōura will decrease overall and shift southwards and towards more mountainous regions. Using the refugia habitat metric, we identified areas of habitat within the current range of kōura, with significant potential refugia habitat outside the species current range. Using the refugia prioritization metric will allow conservation managers to identify habitat for protection and potentially translocation target sites for vulnerable native species.

Abstract. Reproductive behavior in sharks remains poorly understood, with direct observations of mating reported in only a few species. The blue shark (Prionace glauca) is a widely distributed, placental viviparous species, yet direct evidence of mating behavior remains undocumented. Here, we describe the first visual documentation of a putative mating attempt involving blue sharks in the Bay of Biscay, off the Basque coast, observed during a shark ecotourism dive in July 2023. An adult male and an immature female exhibited a sequence of behaviors consistent with shark courtship, including parallel swimming, following, a courtship bite, and an inversion of both individuals. Additionally, we documented females with mating scars across 4 consecutive years, the majority of which were considered immature. These observations align with prior reports suggesting mating attempts between adult males and immature females. The combination of direct behavioral observation and repeated evidence of mating scars highlights the potential reproductive significance of the region and underscores the need for further research on the demographics, habitat use, and reproductive ecology of blue sharks in the Northeast Atlantic.

Abstract. Citizen science, where participants from outside of academia contribute to data collection or analysis, is an important approach in ecological studies that can significantly improve both modelling outcomes and community participation. However, all ecological citizen science platforms developed to date rely on centralised server architecture for data storage and communication with citizen scientists, which can lead to unsustainable server maintenance costs for project managers as well as data sovereignty issues for the concerned communities, thereby endangering project resilience and sustainability after the end of a funded project. Distributed databases, which rely on peer-to-peer technology to store and share data, can address these concerns, but they are complex and conceptually different from centralised systems. As such, their use involves a very steep learning curve that hinders their adoption by citizen science practitioners in ecology, where neither project leaders nor end users are experts in peer-to-peer technologies. In this article, the authors use formal and open-ended feedback from workshops with academics to discuss how well-planned user interface design can be used to facilitate the adoption of peer-to-peer distributed databases in citizen science and provide generalisable key recommendations for the implementation of user interfaces in citizen science applications. In particular, we discuss several key conceptual differences between centralised and distributed applications, such as key-pair authentication and eventual consistency, that must be efficiently and visually communicated to end users. While there is extremely limited literature available on user interface design for distributed systems (and none so far in the ecological field), we find that lessons learned from other fields transfer well to the field of ecological citizen science, that well-designed user interfaces are key to the adoption of new technologies, and that simplicity and efficiency in interface design are more important than showing average users the details of how the underlying technology works. We propose these recommendations as a blueprint for future research and development of citizen science applications based on peer-to-peer distributed database technologies.

Abstract. The European Food Safety Authority (EFSA) has been conducting horizon scanning (HS) activity in the field of plant health, in collaboration with the EC Joint Research Centre (JRC) and the French Agency for Food, Environmental and Occupational Health and Safety (ANSES), since 2017. As of 2024, this activity has produced 130 reports, named newsletters. The aim of this activity is to capture signals from the web about potential threats caused by plant pests from all around the world and to convey them to European Union risk managers in support of their preparedness and timely reactions. The tool used was the Medical Information System (MedISys), a public health surveillance system that continuously monitors the content of more than 3200 scientific and media sources worldwide. The items selected for inclusion in the monthly newsletters are reviewed and validated by a team of experts, while another team carries out further analysis on specific “not-listed” pests. This analysis, PeMoScoring (short for pest and monitoring scoring), is a fast procedure based on a ranking system that warns risk managers of the potential new threats by unknown or not-listed pests. These signals can then trigger actions by risk managers: requests for more assessments by EFSA or facilitation of preventive measures. Recently, a series of workshops and webinars have been organised to foster collaboration among institutions engaged in horizon scanning activities in the field of plant health and to broaden the applicability of this service to other contexts and areas of focus. This article presents an analysis of the data collected from the newsletters, along with a detailed examination of the PeMoScoring outcomes and potential directions for future development. The results highlight the potential of horizon scanning tools in the prevention of emerging threats for plant health and their capacity to support risk management decisions by anticipating challenges and facilitating timely interventions.

Abstract. Some wildlife species can successfully adapt to urban environments. To prevent potential conflict of these species with humans or their pets, a better understanding of the presence of urban wildlife is needed. However, traditional monitoring methods are often inadequate because many privately owned properties are inaccessible. In this study, we analyse reports of European hedgehogs (Erinaceus europaeus or E. roumanicus) and badgers (Meles meles) provided by two long-term citizen science projects in the city of Vienna, Austria – stadtwildtiere.at and roadkill.at – to assess habitat preferences and potential ecological interactions. Vienna has a human population of about 2×106 and covers an area of 415 km2, 50 % of which is green space in the form of forests, parks and private gardens. A total of 356 hedgehog and 918 badger sightings were reported between 2012 and 2023. Sightings of both species were positively associated with a mix of sealed/built-up areas and green spaces with meadows and shrubs. However, sightings of both species were negatively associated with arable land, most likely due to the avoidance of open terrain, reduced food availability or simply because both nocturnal species were more difficult to spot on dark arable land. The steeper the slope of a habitat, the fewer hedgehogs were reported, whereas for badgers, a positive correlation between slope and reports was observed in areas with built-up fractions over 15 %. Overall, we observed hardly any hedgehog reports in areas in which badgers were reported. We conclude that citizen science wildlife monitoring can be a good data source to better understand human–wildlife interactions and could therefore be a model for other urban areas and species.

Abstract. Widely recognized as a major threat to marine biodiversity, invasive species have become a fundamental global concern. With over 500 alien species identified in the Mediterranean alone, European seas are particularly susceptible to the potential ecological and economic threats of invasives. The rate of marine species introductions in the European Union (EU) continues to increase, with climate change facilitating their spread and impact. Crabs and other crustaceans are among the most successful groups of marine invasives and can have significant negative ecological and economic impacts where they become established. To assess the ecological and economic threats posed by these species and to develop monitoring, early response, and mitigation plans, it is important to be able to determine which areas are at highest risk of further range expansion, especially under expected climate scenarios. We studied the current and future distributions of four predatory brachyuran crabs that were previously identified as species of concern for European seas, namely Hemigrapsus sanguineus, Charybdis longicollis, Matuta victor, and Portunus segnis, under various climate change scenarios. Species distribution models were built using an ensemble modelling approach. The results show that the potential distributions for all species are much larger than the current known distributions. Under all predicted climate change scenarios, the climatic conditions for P. segnis, C. longicollis, and M. victor, in particular, are expected to improve in most of the Mediterranean Sea, resulting in an expansion of suitable habitat. The Adriatic and Aegean seas are of particular concern as results indicate that these seas are not only highly suitable under current climatic conditions but also will become more suitable under all climate scenarios. It is, therefore, important to further investigate potential impacts, to increase monitoring, and to explore possible management strategies for these seas in order to manage the invasion of these species and avoid future biodiversity and economic losses.