Biological Invasions

Amphibians are threatened worldwide by various environmental and anthropogenic factors, making non-invasive conservation studies particularly valuable. Newts are one example of a thus challenged amphibian group. In Austria, local population declines of newts have been observed, with the smooth newt (Lissotriton vulgaris) being strongly affected. In this study, skin swabs were used as a non-invasive method to gather DNA, combined with established microsatellite markers. We sampled 139 L. vulgaris individuals at ten sites in North Tyrol, Austria, and, for comparison, 22 L. vulgaris meridionalis individuals in Brixen, Italy. We genotyped all individuals and analysed their population structure. We demonstrate the presence of three distinct L. vulgaris population clusters and find differences in population structure between supposedly introduced allochthonous L. vulgaris individuals and autochthonous populations, as evidenced by differences in Bayesian clustering and elevated values of the fixation index FST. A captive population in a zoological garden, with origins in the Kramsacher Loar in the Tyrolean Unterland (eastern part of Tyrol), performed poorly in terms of conservation genetics, with low genetic diversity (number of alleles) and clear genetic differentiation from populations in the wild (high pairwise FST values with wild individuals, clear separation in cluster analysis). Habitat restoration programs are a crucial aspect of amphibian conservation, as they restore ecosystems that are critical to the animals survival. While breeding programs can play an additional role in the future, they must carefully consider genetic diversity to ensure resilient and viable populations, especially in the face of climate change and chytrid fungus infection. This study emphasizes the significance of considering the geographic origin and genetic diversity of newts in conservation efforts. It also serves as a foundation for future population genetic studies of newts in Austria.

Red Knots (Calidris canutus rufa) rely on Atlantic horseshoe crab (Limulus polyphemus) eggs in the Delaware Bay to refuel during northward migration. Intensive harvest of horseshoe crabs in the 1990s contributed to declines in Red Knot numbers. In 2013, the Atlantic States Marine Fisheries Commission adopted an Adaptive Resource Management (ARM) framework to balance sustainable horseshoe crab harvest with ecosystem integrity and Red Knot recovery, requiring annual stopover population estimates. We estimated the 2025 passage population of Red Knots at Delaware Bay using a Bayesian analysis of a Jolly-Seber mark-resight model which accounts for population turnover and imperfect detection. We also evaluated change in migration timing between 2011 and 2025 with model-derived estimates of arrival at the Delaware Bay each year. The 2025 passage population was 54,043 individuals (95% credible interval: 47,926-61,928), an increase of approximately 17% over 2024 and only the second year since 2011 to exceed 50,000 individuals. Despite the increase, overlapping credible intervals across years indicate a stable stopover population. Migration timing has remained consistent, with 50% of the population typically arriving by 18 May and no evidence of advancement since 2011. These findings provide meaningful input for the ARM framework, supporting sustainable harvest of horseshoe crabs while maintaining adequate foraging opportunities for Red Knots and other shorebirds. Parts of the Introduction, Methods, and Appendices were originally published in Lyons (2024) and are summarized herein.

Invasive round goby Neogobius melanostomus have advanced eastward through the state of New York and provinces of Ontario and Quebec over the past two decades and are approaching Lake Champlain, one of the largest lakes in North America. This manuscript describes international efforts to monitor round goby populations during 2021-2025 on (a) the southern approach to Lake Champlain via the Hudson River and Champlain Canal, and (b) the northern approach to Lake Champlain via the Saint Lawrence River and Richelieu River. Monitoring utilized environmental DNA (eDNA), backpack electrofishing, beach seining, benthic trawling, and viral hemorrhagic septicemia virus (VHSV) testing. In the Champlain Canal, round goby were captured as far north as the downstream side of the C1 dam (97 kilometers [km] from Lake Champlain) while eDNA detections occurred as far north as the upstream side of the C2 dam (90 km from Lake Champlain). In the Richelieu River, round goby were captured as far south as Saint-Marc-sur-Richelieu (82 km from Lake Champlain) while the southern-most eDNA detections occurred near the Canadian side of the international border (4 km from Lake Champlain). Water temperature influenced habitat usage of round goby in the Champlain Canal, with catch rates in near-shore areas declining at < 10 {degrees}C. All VHSV test results were non-detections at the mouth of the Richelieu River, while one positive and two inconclusive results occurred along the Champlain Canal. Together, these data have informed multiple mitigation measures and have implications for management of aquatic invasive species across North America.

Juncus bufonius L. s.l. is a species complex with several ploidy levels, for which species delimitation remains unclear due to a lack of reliable morphological characters and the paucity of molecular studies. To clarify taxonomic and geographic relationships in the complex, we combined genomic, cytometric and morphological data from a broad latitudinal range from England down to Spain. We collected morphometric and cytometric data from 31 populations, and genomic data were obtained through Hyb-Seq using the Angiosperm353 kit for a subset of individuals. These three datasets were combined to explore phylogenetic relationships, population structure, and the validity of four previously proposed morphospecies (J. bufonius s.str., a hexaploid; J. minutulus, a tetraploid; and J. ranarius and J. hybridus, both diploids). Sequencing supported the separation of diploids and polyploids as two distinct taxa, but morphometric characters used previously to describe morphospecies showed continuous variation with no diagnostic value, and were not congruent with genomic and cytometric data. Polyploids likely originated through allopolyploidisation from diploids and tetraploids. Phylogenetic lineages were extensively mixed geographically, both for diploid and polyploid taxa, which suggests repeated long-distance dispersal events for both diploids and polyploids, and no separation of taxa by geography. Splitting of diploids into J. ranarius and J. hybridus was not supported. We recommend J. ranarius be treated as a synonym of J. hybridus, and that tetraploids and hexaploids be grouped under J. bufonius. The observed geographical patterns are consistent with high rates of seed dispersal by migratory waterbirds.

Local temperatures can shape the ability of introduced species to flourish and disrupt novel environments. The emerald ash borer (EAB), Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), is an invasive beetle that threatens ash trees in North America and Europe. To assess the role of temperature on EAB reproduction, we reared groups of adult beetles at one of four temperatures (12, 15, 18, and 21 {degrees}C) and measured reproductive success (laying fertilized eggs and egg hatching). There was no effect of rearing temperature on EAB female lifespans but no eggs laid at 15 or 18 {degrees}C hatched, suggesting these temperatures disrupt the reproductive process of EAB. Females reared at 21 {degrees}C, however, consistently laid eggs that hatched. We then used these results to assess the likelihood of reproductive success over the previous ten years in eight cities in Canada that host EAB. All locations experienced temperatures of [&ge;] 21 {degrees}C, but the number of hours and the number of days above this critical temperature were highly variable. There were ample opportunities in all locations for EAB to reproduce, but EAB in cooler cities would experience thermal limitations thus slowing the spread of EAB populations.

Understanding behavioral differences between non-native and closely related endangered species could be important to aid conservation management. In volume 169 of Zoology, Bels et al. (2025) reported on their comparison of display-action-patterns (DAP) between native Iguana delicatissima and non-native iguanas present on islands of the Guadeloupe Archipelago in the Caribbean Lesser Antilles. Here, we address conceptual and methodological concerns about their work and reanalyze their data given our proposed corrections, primarily a literature-informed adjustment of their "species" category. We additionally utilize online videos from South American mainland I. iguana populations, from where the non-native iguanas in the Guadeloupe Archipelago originate, to better understand the different DAPs between native and non-native iguanas in the Guadeloupe Archipelago. Significant differences in DAP characteristics among "species" categories (native I. delicatissima, non-native iguanas, and hybrids) show that Bels et al. (2025) oversimplified their data analyses by merging all non-native populations into one group. This result indicates the presence of behavioral variation among subpopulations within widely hybridizing iguanid populations, which has been poorly studied. Additionally, videos from mainland populations across two major mitochondrial clades of Iguana iguana show that non-native iguanas on Guadeloupe retained DAP characteristics of those populations from which they originate. We discuss these findings in light of the proposed hypotheses put forward by Bels et al. (2025), of which two can be excluded. Overall, our reanalysis shows that studies focusing on characteristics within settings of complex hybridization in diverse species should acknowledge this complexity.

Sea star wasting disease (SSWD) is one of the most severe marine epidemics recorded, affecting numerous asteroid species and causing widespread population declines. Although a bacterial pathogen has recently been proposed for one species, its generality across taxa and regions remains unresolved. Here, we report the first year-round field assessment of SSWD in the Baltic Sea, a rapidly warming, low-salinity ecosystem hosting a single keystone sea star predator, Asterias rubens. Using field surveys, image-based monitoring, and laboratory experiments, we characterised disease dynamics and potential drivers in Kiel Fjord (western Baltic Sea). SSWD-like symptoms were present throughout 2024, with mean prevalence exceeding 40% across seasons and elevated levels during summer and early autumn, when sea surface temperatures approached 22 {degrees}C and salinity fluctuated between 11 and 17. The mean body radius of asymptomatic individuals declined from 5.6 cm in spring to 2.3 cm in early summer before partially recovering in autumn, consistent with high recruitment of juveniles and selective loss of larger, symptomatic individuals. In a complementary laboratory experiment, survival analyses identified body size as the strongest predictor of SSWD-associated mortality (hazard ratio = 50.8, p < 0.001), with large individuals far more likely to die than small ones. This size-selective mortality, together with environmental constraints on recruitment, suggests that SSWD may be reshaping population size structure and reducing predation pressure on blue mussels, with potential consequences for benthic community dynamics. Continued monitoring will be essential to assess the long-term impacts of SSWD on A. rubens populations and associated benthic ecosystems under ongoing climate change.

Aquatic non-native invasive species are notoriously difficult to eradicate, particularly in pondscapes where populations can spread rapidly, persist in unmanaged refugia, and recolonise treated sites. In such contexts, high-intensity management interventions may be justified, balancing short-term collateral impacts against the prevention of permanent establishment and long-term damages. Chemical eradication methods, such as rotenone or herbicide application, can be effective but raise ethical and environmental concerns. Here, we evaluate quicklime (calcium oxide, CaO) application as a more sustainable alternative control tool for pondscape invaders compared to other chemical methods, using the African clawed frog (Xenopus laevis) invasion in Belgium as a case study. When applied to water, quicklime hydrates exothermically to calcium hydroxide (Ca(OH)), which releases OH ions upon dissolution, temporarily and rapidly increasing pH to lethal levels. In winter 2023, three ponds with breeding populations of X. laevis of low ecological value were drained, fenced, and treated with quicklime. Treatment effectiveness was assessed through pH measurements, visual surveys, and environmental DNA (eDNA) quantification. Immediately after treatment, large numbers of deceased post-metamorphic individuals were recovered, indicating treatment-induced mortality. Eight weeks post-treatment, eDNA concentrations were markedly lower in two of the three ponds (reductions of 100% and 80%) compared to those during the same period one year later. Although eDNA concentrations increased again during the following summer suggesting partial population recovery through survival and/or recolonisation, they remained lower than pre-treatment conditions. Water pH returned to near baseline levels within one month. We provide the first field-based preliminary evidence that quicklime can induce large-scale mortality in X. laevis populations in small to medium-sized ponds. We discuss practical considerations, limitations, and broader applicability, proposing quicklime as a high-intensity option within integrated management strategies for pondscape invaders.

Biological invasions are a major component of global change and biodiversity loss. Rumina decollata, a Mediterranean land snail, has been introduced beyond its native range through human-mediated dispersal and is now widely distributed across much of Argentina. Here, we investigated the origin of Argentine populations using mitochondrial COI sequences from Argentine populations spanning a broad latitudinal and environmental gradient. All analysed populations clustered within the mitochondrial lineage previously identified as invasive worldwide. A single haplotype identical to sequences from Spain and Portugal dominated most Argentine populations, while two additional haplotypes matched lineages from Portugal and southern France, indicating multiple introduction events followed by extensive secondary spread. Despite low mitochondrial diversity, R. decollata has successfully colonised diverse environments, suggesting that reproductive traits such as self-fertilisation may have contributed to population persistence following introduction. In addition, body and sole colouration was variable and did not reliably diagnose the invasive clade. Our results highlight how repeated introductions and life-history traits interact to facilitate establishment and spread, even under strong demographic constraints.

Reduced competition or facilitation between kin relative to nonkin can improve plant performance, particularly under resource-limited conditions. Understanding whether kin interactions differ between invasive and native species may provide insights into the mechanisms underlying the persistence and spread of invasive species, particularly for species that spread clonally. To explore this, we conducted a greenhouse experiment using the invasive Alternanthera philoxeroides and its native congener A. sessilis in China. For both species, we grew central plants without or with neighbors, and for the latter we had three intraspecific neighbor kinship treatments (kin only, nonkin only, and both kin and nonkin [mixed] neighbors). To test whether kinship effects are affected by resource limitation, we grew the plants under two watering conditions (well-watered and drought-stressed). Our findings revealed that at both the group (i.e., pot-level) and individual levels, invasive plants had a higher biomass production and experienced a less negative relative neighbor effect in kin groups than in nonkin groups, while these patterns were reversed in the native species. Although aboveground architecture of central plants did not differ significantly between kin and nonkin neighbors in either species, neighbor plants of the invasive species produced fewer nodes in kin groups than in nonkin groups, while the reverse was true for the native species. These patterns were not affected by the watering treatment. Together, these results indicate that while the native plants has stronger kin competition, the invasive species has reduced kin competition. Such reduced competition among kin in the invasive Alternanthera philoxeroides may enhance its population dominance and facilitate its spread.

Antisense vivo-morpholino oligonucleotides (vivo-MOs) allow transient gene knockdown in adult organisms with high specificity and low toxicity. Vivo-MOs are used in cell culture and in many established model organisms, but a method for their use has not been described in threepsine stickleback (Gasterosteus aculeatus (Linnaeus, 1758)). Stickleback are an emerging model system used in evolutionary and ecological genetic studies. While genomic techniques are commonly used in stickleback research, there are few studies and tools available to assess gene function in-vivo, especially for genes that may be difficult to knock out by CRISPR (e.g., lethal knock-outs). Here, we test the use of splice-blocking vivo-MOs for gene knockdown in stickleback using intraperitoneal injection of vivo-MOs targeting three candidate genes. Gene expression was assessed in the liver, spleen, and intestine. Successful knockdown of Spi1b was observed in the spleen, however, we observed no other significant knockdown at either timepoint tested. Injection of a fluorescently labeled control vivo-MO confirmed delivery to each target organ, validating this approach, but delivery was variable which may explain inconsistent effects. These results indicate that vivo-MOs have potential as a tool for in-vivo gene knockdown in stickleback. Optimizing delivery methods could improve reproducibility and knockdown efficiency in future studies.

Artificial pond construction is widely used in wetland restoration, yet biodiversity outcomes depend strongly on design and subsequent management. We tested how different regimes (grazing, mowing, and no management) influence habitat structure, water conditions, and aquatic macroinvertebrate diversity in newly excavated experimental ponds within an eutrophic wetland in South Moravia (Czechia). Across four focal groups (Mollusca, Odonata, Coleoptera, Heteroptera), we observed rapid colonisation of the newly built ponds. Species richness and densities rose during early development, dropped after drying events, and then partially recovered, indicating repeated "resetting" of communities under fluctuating hydrology. Periodic drying also prevented fish stock establishment. Management significantly affected species composition and both grazed and mowed ponds displayed higher densities (abundances) than controls, but differed only slightly in terms of species richness. The grazed ponds were characterised by high sunlight exposure, reduced reed dominance, and trampling-generated high littoral heterogeneity. These ponds showed highest numbers of taxa adapted to shallow and warm waterbodies, muddy substrate, semiaquatic microhabitats, or newly emerged and disturbed habitats. The mowed ponds promoted dense submergent vegetation, supporting Odonata representation and other taxa requiring aquatic vegetation. The control ponds remained highly shaded by high-grown reed, organic-matter rich, hosting a set of taxa tolerant of low-light, low-oxygen conditions. At the wetland scale, multiple small ponds increased overall diversity through high between-pond heterogeneity. Our results highlight that pond construction alone is insufficient for wetland restoration: follow-up long-term management regimes, especially extensive grazing, can rapidly generate structural heterogeneity and sustain diverse aquatic invertebrate assemblages in eutrophic wetlands.

The ecological and evolutionary processes determining species range limits remain poorly understood. Ultimately, range limits depend on the species abilities to persist under heterogeneous conditions, by adaptive differentiation and phenotypic plasticity, including transgenerational effects. To investigate ecological differentiation and transgenerational effects in the clonal invasive knotweed, Reynoutria japonica, in Europe, we conducted a two-phase transplant experiment: plants sampled along the entire latitudinal gradient were planted in three sites located at the northern range margin, mid-range and near the southern range margin, and then re-transplanted among all three sites after two years. Biomass production and allocation were generally not associated with latitude of origin and previous growth at the same site did not promote performance. We therefore find no evidence that adaptive differentiation or transgenerational effects contribute to the wide distribution of R. japonica in Europe. However, at the northern site, with a 25% shorter season, knotweed plants invested much less biomass below-ground, and the pattern was further strengthened in plants that had grown in the northern site in the previous generation. Overwintering below-ground rhizomes are essential for survival and spread. We further explored limiting climate conditions in a species distribution model for the European range and found that mean annual temperature and temperature annual range are the main predictors of the European distribution of R. japonica. Taken together, our study suggests that low temperatures and associated short seasons may pose a limit to the broad environmental tolerance of R. japonica and restrict its northward spread by reducing below-ground biomass accumulation.

Climate change is dramatically affecting species distribution and phenology worldwide. Its impact on arthropod vectors, such as the Aedes albopictus mosquito, has important consequences for biting nuisance and arbovirus transmission risk. Here, we assess the impact of climate change on the presence and abundance of Ae. albopictus, as well as the risk of dengue transmission over France during the 21st century. We use a mechanistic model that we adjusted against records of recent autochthonous cases of dengue in France. We simulate climatic suitability indicators, such as the adult abundance during the activity period, epidemic risk and secondary cases of dengue under different climatic and demographic scenarios at different periods up to 2085. Future simulations are based on a high-pressure scenario (high greenhouse gas emissions, high demographic growth) and a median-pressure scenario (median greenhouse gas emissions, demographic stagnation). To account for climate model uncertainty, we repeat the simulations for three different regional climate models. By 2085, in the high-pressure scenario, most of France (89-96%) will be climatically suitable for the establishment of Ae. albopictus, with the exception of mountain ranges. Similarly, autochthonous transmission of dengue will be theoretically possible in all colonized areas except over northern lowlands (71-95%). In the median pressure scenario, both climatic suitability for establishment (49-89%) and autochthonous dengue transmission risk (31-82%) exhibit large variation. Low population density areas show moderate suitability for vector establishment but exhibit the highest potential for dengue transmission. Overwintering mechanisms, such as egg diapause, indispensable for survival in temperate climates, may not be necessary along the Mediterranean and Basque coasts, allowing activity of the vector all year-round in the future.

Abstract summaryThis report presents a preliminary bryoflora for Grand Staircase-Escalante National Monument (GSENM) in southern Utah. The inventory included over 1000 collections made across 40 localities (i.e. macrohabitat types) spanning two ecologically important gradients in bryophyte habitat: shade and moisture availability. At present, the growing checklist contains 117 taxa of liverworts and mosses including 27 families, 65 genera, 116 species, 9 varieties, and 1 subspecies. Noteworthy records include 49 putative taxa new for the state of Utah, and 2 undescribed species in the genera Grimmia and Schistidium. We propose 4 of these species be considered for addition to the recently revised bryoflora of North America. As expected for arid and semiarid environments, the bryophytes of GSENM are predominantly acrocarpous mosses (75%) followed by pleurocarpous mosses (16%), thalloid liverworts (7%), and leafy liverworts (2%). The most diverse families included xeric-soil acrocarpous mosses in the Pottiaceae (35%) and xeric-rock acrocarpous mosses in the Grimmiaceae (15%). Both xeric and mesic species were recovered in the Bryaceae (10% of species) while the pleurocarpous Amblystegiaceae included mesic and hydric species (7%). Most species in the bryoflora have broad global or disjunct distributions, but notably, the known distribution of 17 species appears limited in the United States, or globally, and warrant monitoring in GSENM. Using floristic habitat sampling across 19 macrohabitat types (combinations of 6 topography and 7 vegetation classes), mean site richness was 17.2 {+/-} 9 (SD) and ranged from 4 to 34 species. Six diversity hotspots supported [&ge;]30 species and were canyons with perennial or ephemeral streams dominated by mixed conifer, hardwood-riparian, riparian, or pinyon-juniper vegetation. High richness is likely supported by greater habitat diversity including xeric, mesic, and hydric conditions on variable substrates (e.g. rock, soil, biocrust, downed wood, seeps, and riparian aquatic/semi-aquatic habitat). Consequently, managing and monitoring diversity under future climate change and land-use alterations will necessitate a habitat-stratified approach that utilizes repeated floristic habitat sampling to document changes in site-level richness and to predict other candidate diversity hotspots on the basis of microhabitat-level diversity, which could be assessed by trained non-bryologists. Collection data are available to the public as georeferenced and photographed observations of half of the bryophyte collections on our iNaturalist.com project, Bryophytes of Grand Staircase Escalante, available for scientific, educational, or outreach activities. Observations are accessible to visitors (via the smartphone app) who wish to know what species have been found along popular trails in GSENM. Landscape-level richness may not reach that of the neighboring Grand Canyon National Park (>155 species), which supports a unique high-elevation bryophyte community sheltered in the mixed conifer and spruce-fir forests of the North Rims Kaibab Plateau. Future collecting by experts will inevitably uncover more species in this ecologically diverse monument important to conserving dryland bryophyte diversity and ecosystem function. This study will serve as a baseline for future research and long-term monitoring related to climate change impacts on dryland bryophytes including biocrust species. O_FIG O_LINKSMALLFIG WIDTH=158 HEIGHT=200 SRC="FIGDIR/small/708354v1_ufig1.gif" ALT="Figure 1"> View larger version (106K): org.highwire.dtl.DTLVardef@c50925org.highwire.dtl.DTLVardef@1db65c3org.highwire.dtl.DTLVardef@f60909org.highwire.dtl.DTLVardef@cb5244_HPS_FORMAT_FIGEXP M_FIG C_FIG Cover photos (by T. A. Clark): View of sandstone canyon wall along the Escalante River Trail taken during a July collection trip in 2015 (top) during which riparian bryophytes were collected by authro, T. A. Clark, (shown in photo) at a sandstone seep (bottom). Bureau of Land Managements National Landscape Conservation System Grant Cooperative Agreement #L14AC00275 issued to P.I. Lloyd R. Stark, UNLV O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=151 SRC="FIGDIR/small/708354v1_ufig2.gif" ALT="Figure 2"> View larger version (88K): org.highwire.dtl.DTLVardef@86109eorg.highwire.dtl.DTLVardef@1ad0efborg.highwire.dtl.DTLVardef@b2c239org.highwire.dtl.DTLVardef@1ed4a4a_HPS_FORMAT_FIGEXP M_FIG C_FIG Copyright 2020 by the authorsAll content contained herein is the property of the authors and all images the property of Theresa A. Clark and should not be used without permission except for education, in which case inclusion of the author/photographers name in citation or superimposed over any image(s) is requested.

Simpsonaias ambigua (Salamander Mussel), is a small and thin shelled freshwater mussel often found in difficult to survey habitats, such as beneath slab stones, in the crevices of rock walls, or buried within roots of emergent vegetation and in undercuts of banks. The use of environmental DNA (eDNA - genetic material released from urine, waste, mucus, or sloughed cells) sampling may improve detection and assessment of presence / absence for this rare mussel in comparison to visual tactile techniques. This study completed side by side comparisons of traditional mussel searches and eDNA for a direct assessment of mussel detection efficiencies. Surveying was conducted in several waterbodies of different habitat characteristics with varying abundances of S. ambigua. Additionally, a broad assessment of S. ambigua presence was conducted throughout the proposed critical habitat reach of the Blanchard River in northwest Ohio, to assess if the species remained extant. All eDNA samples were also assessed for the presence of Necturus maculosus (Mudpuppy), the obligate host species for S. ambigua. The eDNA sampling successfully detected S. ambigua from multiple sites and watersheds where it was found with visual surveys. In some cases, eDNA detections occurred in locations where over 16 hours of search yielded only a single individual or fresh dead shells, supporting the sensitivity of eDNA for detection of rare species. Furthermore, probability of detection analysis suggests eDNA sampling can provide high detection efficiency with relatively low effort in comparison to visual searches. The development and validation of an eDNA protocol for the simultaneous detection of S. ambigua and its host salamander increases survey efficiency, reduces field costs, and can support future conservation efforts for listing drainages of extant populations and monitoring conservation goals.

The rapid expansion of oil palm plantations in Southeast Asia has caused extensive deforestation and landscape fragmentation. Riparian buffers (vegetated strips along the edges of rivers) have been shown to enhance biodiversity, water quality, and erosion control. However, plantation managers have raised concerns that these buffers may harbour pests such as nettle caterpillars, bagworms, and rhinoceros beetles (Oryctes rhinoceros). These pests damage the palms and facilitate the spread Ganoderma boninense (a fungal pathogen). Using causal inference modelling we examined how riparian buffer characteristics (width and habitat quality), oil palm age, and surrounding landscape features influence pest and disease incidence in oil palms adjacent to riparian areas in Sabah, Malaysian Borneo. We surveyed 47,500 palms for pest and disease damage and used mark-release-recapture techniques to track O. rhinoceros movements in oil palms adjacent to riparian buffers. Most O. rhinoceros activity (66.30%) occurred within the plantations, and only 6.10% occurred within riparian buffers, with limited movement between habitats. Oil palm age was a dominant driver of pest attacks: young palms were more susceptible to lepidopteran caterpillars and O. rhinoceros, whereas G. boninense was more prevalent in mature palms. Neither the surrounding forest cover nor the quality of the riparian buffer affected the incidence of pest attacks. Riparian buffer width increased O. rhinoceros attacks, reduced G. boninense infection, and had no effect on lepidopteran caterpillars, highlighting that surrounding forest cover and riparian buffers do not drive pest attacks in oil palm plantations. Instead, management of oil palms within the buffers s is likely to be more important in managing pests; increases in invasive oil palms within the buffers increased the incidence of caterpillar damage, and higher numbers of remnant old oil palms increased O. rhinoceros attacks in adjacent oil palms. Overall, riparian buffers were found to contribute little to pest spillover, suggesting that their biodiversity and connectivity benefits outweigh minor pest risks, especially if invasive young and remnant old oil palms within the buffers are effectively managed and native vegetation restored.

Effective monitoring of the critically endangered European eel (Anguilla anguilla) is essential for conservation planning and regulatory decision-making, particularly in heavily fragmented rivers. Environmental DNA (eDNA) methods offer sensitive alternatives to traditional surveys, but there is uncertainty around whether targeted assays or community-wide approaches are better suited to achieve monitoring objectives. We compared eDNA metabarcoding and species-specific quantitative PCR (qPCR) for detecting A. anguilla across 145 pumped catchments in the Fens, East Anglia, England. All sites were sampled once initially, and sites negative for A. anguilla were re-sampled based on metabarcoding results. This allowed comparison of detection rates from a single water sample and site-level retrospective identification of sites where qPCR could have identified A. anguilla in earlier samples. The findings were also set in the context of the wider biodiversity information generated by metabarcoding. From the initial (single) water sample, qPCR detected A. anguilla at seven more sites than metabarcoding (17 versus 10). With repeated sampling, metabarcoding detected A. anguilla at 43 sites, including all but one of the sites where qPCR detected A. anguilla, and ten sites where qPCR did not detect A. anguilla within the same number of samples. Indeed, the additional sampling effort required to detect A. anguilla with metabarcoding at sites also positive with qPCR was small relative to the overall sampling effort. Furthermore, metabarcoding additionally detected 28 non-target fish species alongside fish, amphibian and mammal species of conservation concern. Our results highlight trade-offs between target-species sensitivity and the broader ecological information provided by each method, and support metabarcoding as an effective tool for a holistic conservation approach, with the additional community data outweighing the marginally increased sensitivity of qPCR.

ContextGenetic diversity is essential for the persistence and future adaptation of species. However, human-driven habitat fragmentation results in population isolation, often leading to rapid loss of genetic diversity and adaptive capacity. Genetic management of focal taxa may be overlooked in many threatened species conservation programs. The Endangered southeastern Australian mallee emu-wren Stipiturus mallee is a species that may benefit from genetic management. Its current range encompasses patchily distributed sub-populations, prone to bottlenecks and genetic drift. Thus, the reintroduction to areas from which the species has been locally extirpated requires careful selection of founders to maximise genetic diversity. AimsWe analyse reduced-representation genomic data from seven sampling areas across the global meta-population to design a translocation strategy that maximises heterozygosity and retention of mallee emu-wren allelic diversity. MethodsWe estimated genetic structure, genetic diversity within, and differentiation between subpopulations, thus testing previous inference based on 12 length-variable loci of low population differentiation with 10,840 genome-wide SNP loci. We also estimated effective population sizes to identify populations in need of genetic augmentation, Finally, we used metapop2 simulations to estimate the relative contributions of each population to global genetic diversity of the species and to estimate the source and number of founders that would maximise heterozygosity and allelic richness in a hypothetical newly established population. Key resultsWe found weak genetic structure across all sampling areas, supporting previous conclusions that the global mallee emu-wren population should be considered a single genetic unit for management purposes. Low but significant Weir and Cockerham pairwise FST among locations indicated differentiation between sampling areas, suggesting that contemporary gene flow is restricted. Effective population sizes for the two regions supporting the largest numbers of mallee emu-wrens were below the threshold associated with reduced adaptive potential. ConclusionsThe genetic health and adaptive potential of sampled mallee emu-wren sub-populations are at risk. Implications The global mallee emu-wren meta-population would likely benefit from genetic augmentation, including reciprocal gene flow between extant sub-populations. To maximise genetic diversity in newly established populations, managers should prioritise gene-pool mixing with founders sourced from all sampled areas.

O_LISubmerged macrophytes are central to freshwater ecosystems functioning but are declining globally under multiple anthropogenic stressors. We aimed to identify general patterns in physiological responses and interaction types, and to assess whether a mechanistic understanding of stressor interactions can be developed from published evidence. C_LIO_LIWe systematically reviewed 12,858 records, identified 172 relevant papers, and extracted effect sizes from 124 experiments included in the meta-analysis. C_LIO_LIMost studies examined combinations of nutrient enrichment, shading, toxic trace metals, warming, and emerging contaminants such as PFAS and microplastics, typically under simplified 2 x 2 factorial laboratory designs. Additive effects dominated (50%), while synergistic interactions were relatively infrequent (14%). Antagonistic interactions often reflected dominance of a single stressor or compensatory responses, whereas synergisms were most frequent with metals combined with co-stressors enhancing bioavailability. C_LIO_LIOur synthesis suggests that accumulated stressors cause negative, but not necessarily amplified, responses, although the limited number of experiments testing more than two stressors means synergistic effects may be underestimated. We propose Stuckenia pectinata as a model organism because of its cosmopolitan distribution, experimental tractability, and available genomic resources, and argue that expanding stressor complexity, duration, and taxonomic breadth will strengthen predictions of macrophyte responses and inform freshwater conservation under global change. C_LI