Aquatic Conservation: Marine and Freshwater Ecosystems
○ Wiley
Preprints posted in the last 30 days, ranked by how well they match Aquatic Conservation: Marine and Freshwater Ecosystems's content profile, based on 12 papers previously published here. The average preprint has a 0.01% match score for this journal, so anything above that is already an above-average fit.
Probst, W. N.
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The use of marine space by human activities is globally increasing, resulting in a competition with spatial management measures for marine conservation. Within the European Union (EU) these measures are currently implemented by the union member states to achieve the UN sustainable development goal (SDG) of protecting at least 10 % of the national marine waters. Further, the EU Marine Strategy Framework Directive (MSFD) and the Nature Restoration Regulation (NRL) are the two main legal means for the implementation of ambitious spatial conservation targets for benthic habitat types, which can range from 10 - 90 %. This study analysis how the targets of the MSFD and NRL are currently met in the German waters of the North Sea and which areas the full implementation of both legislations might require. A spatial optimisation tool ("prioritizr" in R) was used to identify optimised solutions for the conservation of up to 75 % of NRL benthic habitats. The current spatial conservation measures (which ban demersal trawling within certain zones of designated marine protected areas, MPA) are not sufficient to reach the targets of the MSFD and NRL. Extending the exclusion of demersal trawling to the entire area of the MPAs would achieve a sufficient coverage for all habitats except for offshore sand and mud habitats. These could be further protected, when including areas for offshore wind farms, where trawling is also banned. However, to date it is unclear, if and how these (or other human use) areas could be included into spatial conservation regimes, a debate that needs to be resolved to allow for the achievement of the ambitious MSFD and NRL targets.
Bate, J.-M.; Poblete, A.; Dagamac, N. H.
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Philippine freshwater ecosystems are considered one of the most diverse ecosystems harboring numerous fish species. However, in the Philippines, these ecosystems are threatened by invasive species that potentially disrupt ecological balance. In this study, we focused on the vermiculated sailfin catfish Pterygoplichthys disjunctivus, an invasive aquarium species reported in several Philippine aquatic ecosystems. Despite its documented spread, its potential range under a rapidly changing climate remains poorly understood for the country. Hence, in this study, we utilized the MaxEnt model to predict its near-current and future habitat suitability in the Philippines. Using 11 reported occurrences, our model showed high predictive accuracy (AUC = 0.882{+/-} .034, TSS = 0.7394 {+/-} 0.154, SEDI = 0.971 {+/-} 0.019). Across the current and future scenarios, slope was the primary contributor (78.7% - 81.3%), followed by BIO 10 or the mean temperature of the warmest quarter(18% - 27.8%), and flow accumulation (0% - 5.2%). However, for the SSP126 scenario, BIO10 is projected to triple by 2050 (18 - 48%). Current projections identify high-risk regions, particularly central Luzon (Laguna de Bay and Lake Taal), the Cagayan River Valley, and portions of eastern Mindanao (Agusan Marsh and Lake Mainit). Sankey transition analysis confirms a high habitat stability rate (>73%) for high-suitability pixels in both SSPs, indicating persistent invasion risk. Overall, our study provides a framework for invasive species management and contributes to the conservation of Philippine aquatic ecosystems.
Guilford-Pearce, B. J.; Staiger, M.; Stevens, G. M. W.; Doherty, P. D.; Ali, J.
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Reef manta rays (Mobula alfredi) are threatened by fishing and other anthropogenic threats. Which, when coupled with conservative life history traits, have made this species vulnerable to extinction. Spatiotemporal ecological knowledge, such as site fidelity and visitation patterns to key aggregation sites, are imperative for effective conservation management of M. alfredi. A novel method of environmental sensing, remote underwater photo systems (RUPs), was employed to understand drivers of M. alfredi habitat use and resighting patterns. RUPs were deployed at four cleaning sites around Laamu Atoll, Maldives. Between March 2021 and May 2023, 455,458 photos were analysed. Generalised linear models revealed increases in M. alfredi presence in response to high chlorophyll-a concentrations, low illumination moon states, the Southwest Monsoon, and in the morning, while human presence had no effect. Branchial spot patterns allowed for 81 M. alfredi individuals to be identified, from 629 sightings, representing 51.59% of Laamu Atolls previously identified population (n = 157). Cleaning stations are visited more intensively during periods of increased productivity of the Southwest Monsoon, likely in response to greater foraging opportunities near the study areas. Additionally, moon state, used as a proxy for tidal strength, was associated with increased visitation during new moon periods, suggesting that weaker tidal states may facilitate presence. These data support integrating RUPs with observational surveys to improve inferences about habitat use and our understanding of cleaning sites frequented by M. alfredi. This study aims to inform the implementation of Laamu Atolls first marine protected area management plan.
Renn, C.; Ciotti, B. J.; Sims, D. W.; Edwards, A.; Turner, R. A.; Hosegood, P.; Sheehan, E. V.
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Designing effective spatial management for chondrichthyans (sharks, skates, rays and chimaeras) requires incorporating critical areas, sites essential for population maintenance, such as reproductive and feeding areas. Yet most area-based measures have been developed without consideration of chondrichthyan habitat use. The Important Shark and Ray Area (ISRA) initiative has been pivotal in designating priority areas through a rigorous, consultative process. To complement this, our study offers researchers a testable definition for generating robust evidence to strengthen future critical area delineations and related management decisions. We define critical areas using three criteria: 1) relative frequency of use, (2) extended within-year occupancy and (3) repeated use across years. This framework enables objective comparison among candidate sites and is generalisable across different critical area types. The definition builds upon established early-life-stage habitat concepts and applies these to broader life-history functions. The utility of this framework is then demonstrated through a systematic review of contemporary peer-reviewed literature of critical chondrichthyan areas in the European Atlantic. The review highlighted 62 critical areas with Strong evidence and 41 areas of Moderate strength evidence, which informed the European Atlantic ISRA selection process. Research effort was concentrated in inshore areas, particularly around the British Isles and Portugal, with biases towards large, threatened and commercially valuable species, whilst chimaeras were notably underrepresented. Early-life stage areas were most frequently identified, whereas resting areas were rarely documented. Evidence patterns and biases are examined in the context of evolving critical area concepts to advance their development and improve the quality and breadth of future research. By outlining a testable definition, identifying key knowledge gaps, and proposing research and reporting guidelines, this work enhances the consistency, comparability, and spatial coverage of future chondrichthyan habitat research to support its application to conservation planning.
Garibian, P.; Rubleva, V.; Burlakov, A.; Valeyev, V.; Kasatkina, A.; Kirova, V.
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Intraspecific morphological variability presents a complex challenge for biological systematics and biomonitoring, particularly for organisms with high phenotypic plasticity, such as zooplankton. Morphological differences between individuals of the water flea species Bosmina longirostris (Crustacea: Cladocera) are difficult to distinguish visually, parthenogenetic females look morphologically uniform within the species; nevertheless, they demonstrate differences attributable to their geographic origin and developmental stage. A reference dataset of microscopic images was created for the study, including populations from two geographically separated regions (seven ones from European Russia and seven ones from Sakhalin Island in the Pacific Ocean (Far East of Russia) and two age groups, demonstrating the ability of a neural network classify to successfully the intraspecific morphological variation. This study demonstrates that deep learning methods are prospective for the detection and understanding of fine morphological intraspecific differences in the cladocerans.
Duarte, S.; Costa, F.
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Early detection and monitoring of non-indigenous species (NIS) is crucial to prevent their establishment and to reduce ecological and economic impacts in coastal ecosystems. Traditional monitoring approaches, which rely largely on morphological identification of collected organisms, are often time-consuming and may fail to detect species that occur at low abundance, are morphologically cryptic, or are present in the form of inconspicuous life stages. DNA-based approaches, particularly those resorting to environmental DNA, have demonstrated high aptitude for biodiversity monitoring and biosecurity surveillance. By examining the genetic material from bulk community samples or released into the environment, DNA-based approaches enable the detection of species without the need for direct observation, thereby increasing detection sensitivity and expanding the scope of monitoring programs. Despite the rapid growth of its employment in marine monitoring, a global synthesis of the status and trends of DNA-based approaches for detecting NIS in this environment has been lacking. Here, we present such synthesis, based on 146 published studies employing DNA for NIS detections in coastal environments. Two main methodological approaches were used across the reviewed studies, namely DNA metabarcoding which was applied in 49% of studies, closely followed by targeted single-species PCR assays, used in 42% of the studies. A smaller proportion of studies (10%) combined both approaches, integrating broad community screening with targeted detection to improve surveillance efficiency. Globally, 752 NIS were detected across disparate taxonomic groups, with metazoans representing the largest proportion of detections (464 species), followed by Chromista (210 species) and Plantae (77 species). Among these, the most frequently detected taxonomic groups included Dinophyceae (Dinoflagellata), Teleostei (Chordata), Florideophyceae (Rodophyta), Polychaeta (Annelida), Copepoda and Malacostraca (Arthropoda), and Ascidiacea (Chordata). At the species level, several well-known marine invaders were recurrently reported, including Bugula neritina (Linnaeus, 1758), Styela plicata (Lesueur, 1823), Acartia (Acanthacartia) tonsa Dana, 1849-1852, and Botryllus schlosseri (Pallas, 1766), highlighting the ability of DNA approaches to detect widespread and established invaders across different regions. The mitochondrial cytochrome c oxidase subunit I (COI) gene was the most widely used genetic marker, reflecting its broad taxonomic coverage and extensive representation in reference databases, particularly for targeting Metazoa. Ribosomal RNA genes, particularly 18S and 16S rRNA gene markers, were also frequently employed to target a wider range of eukaryotic taxa. Regarding sampled substrates, water was by far the most analyzed substrate, followed by zooplankton and biofouling communities collected from man-made structures. Notably, approximately 31% of all NIS detections reported in the reviewed studies constituted new regional records. These results highlight the potential of eDNA for coastal monitoring but also underline important limitations. Persistent geographical, taxonomic, and methodological biases can affect detection outcomes, and reliance on single sample types or markers may increase false negatives - particularly critical for NIS early detection. Therefore, multi-marker and multi-substrate approaches are essential to improve detection reliability and support effective biosecurity strategies. As reference databases continue to expand and methodological protocols become increasingly standardized, DNA-based monitoring is likely to play a central role in future management and surveillance of biological invasions in coastal ecosystems. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=133 SRC="FIGDIR/small/722998v1_ufig1.gif" ALT="Figure 1"> View larger version (75K): org.highwire.dtl.DTLVardef@17948b1org.highwire.dtl.DTLVardef@193832dorg.highwire.dtl.DTLVardef@189033dorg.highwire.dtl.DTLVardef@33cddf_HPS_FORMAT_FIGEXP M_FIG C_FIG
Ellis, M. B.; Lewis, H. M.; Cameron, T. C.
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There is an urgent need to gather data on harvest rates of waterbirds in Europe to assess the sustainability of hunting. Estimates of total waterbird harvest in the United Kingdom (UK) and the relative harvest of different huntable species come from two separate surveys, the Value of Shooting (PACEC 2014) and National Gamebag Census (NGC, Aebischer 2019), and these have been recently used to explore the likelihood of unsustainable harvests of wild waterbirds by UK hunters (Ellis and Cameron 2022; Madden et al., 2025). The reliability of these sustainability estimates depends on how representative the original surveys are of hunter behaviour and success. There are also 1-3 million released game-farm mallard (Anas platyrhynchos) that takes up considerable and unquantified proportions of the UK waterbird harvest. Here we explore uncertainties in the UK winter harvest of wild waterfowl by comparing estimates from the NGC dataset with those from the Crown Estate coastal hunting clubs, and a novel approach using analysis of social-media images (2019/20 to 2023/24). We explore the difference in species-specific harvest with and without the uncertainties in the number of released mallard and the total number of duck harvested in the UK. Waterbird harvest estimates differ markedly depending on the input dataset and whether released mallard are included in the analysis. Confidence intervals of each estimate are inflated by uncertainties in the number of released game-farm mallard contributing to, and the size of that national bag. Estimates extrapolated from social media suggest the national harvest of several species may be considerably larger than the corresponding NGC estimates (e.g. Teal *2.07 and gadwall *11.2), while mallard harvests away from formal shoots represented by NGC are significantly lower (*0.71). Excluding released mallard reduces the statistical estimate of total wild duck harvest by 56-63%, which would have biologically significant effects if realised.
Lamarins, A.; Waples, R. S.; Piironen, J.; Primmer, C. R.
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1Effective population size (Ne) is a critical parameter for evaluating the evolutionary and persistence potential of endangered populations and for designing sustainable conservation strategies. Captive breeding and release programs are widely used across taxa to reduce risk of extinction when natural reproduction is insufficient or no longer possible, making it essential to assess their consequences. We used the case study of the landlocked Saimaa salmon (Salmo salar), one of the most critically en-dangered salmonid populations in Europe, with unique evolutionary significance due to its isolation from other populations since the last glaciation. Using long-term demographic data (1969-2024) from wild-caught founders of a captive breeding and release program, we estimated the effective population size under multiple scenarios of variance in reproductive success. Across scenarios, Ne ranged from 33 to 81 individuals, representing 32%-75% of the census size. Captive breeding practices aimed at equalizing parental contributions during fertilization and early life stages increased Ne by 12% compared to natural reproductive conditions. However, variation in survival after early developmental stages, typically beyond direct management control, remained a key determinant of Ne. Despite recent increases in the number of founders, the population remains genetically vulnerable due to historical bottlenecks. These results highlight that while captive breeding programs can partially mitigate genetic risks, their effectiveness depends critically on both controlled and uncontrolled sources of variance in reproductive success. Strengthening such programs may require combining breeding management with habitat restoration and, where appropriate, genetic rescue to ensure the long-term evolutionary potential of such unique and endangered populations.
Hanfling, B.; Griffiths, N. P.; Macarthur, J. A.; Morrisey, B.; Svobodova, D.; Pritchard, V. L.; Tree, A.; Gaywood, M. J.
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O_LIEnvironmental DNA (eDNA) metabarcoding is an emerging tool for biodiversity assessment in freshwater systems, offering high-resolution insights into community composition. Here, we apply eDNA metabarcoding to evaluate the ecological impacts of Eurasian beaver (Castor fiber) activity within a seminatural enclosure in the Scottish Highlands. C_LIO_LIWe collected seasonal water samples from nine sites, six influenced by beaver dams and three control sites with no evidence of beaver engineering, across a 40-hectare enclosure. Samples were analysed for vertebrate and macroinvertebrate diversity using established 12S and COI markers. C_LIO_LIVertebrate alpha diversity did not differ significantly between beaver and control sites, likely reflecting the small spatial scale and low species richness of upland Scottish streams. However, community composition differed significantly between treatments, especially for fish (PERMANOVA, R2 = 0.55, P < 0.001), with beaver-influenced sites dominated by three-spined stickleback and control sites by brown trout. Macroinvertebrate communities showed a 78% increase in gamma diversity in beaver-modified habitats relative to controls. Species composition varied strongly with beaver presence (PERMANOVA, R2 = 0.29, P < 0.001), likely due to the creation of lentic-lotic mosaics and associated microhabitat diversity. Seasonal variation was significant in both taxonomic groups, with the lowest species richness and highest community dispersion observed in summer, probably reflecting hydrological and temperature-driven dynamics in eDNA production and transport. C_LIO_LIOur findings reinforce previous evidence that beaver dam-building activity enhances beta diversity in headwater systems. Additionally, we demonstrate that eDNA metabarcoding is a sensitive method for detecting spatial patterns in freshwater biodiversity associated with these activities at scales ranging from tens to hundreds of meters. These approaches could inform future monitoring strategies aligned with landscape-scale beaver management and reintroductions. C_LI
Wu, T.; Li, C.
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The genus Trichiurus is the most economically valuable fish in the family Trichiuridae, currently recognized to include 10 valid species. However, historically numerous morphologically similar congeners have been erroneously assigned as synonyms or subspecies of T. lepturus. In this study, we examined 16 hairtail specimens collected from the southern waters of Java Island, Indonesia. Integrated morphological and mitochondrial phylogenetic analyses (COX1 and 16S rRNA), compared against global Trichiurus sequences, revealed that these specimens form an independent lineage that diverged early from other congeners. Consequently, we describe this lineage as a previously undescribed cryptic species. Diagnostic characters include: first anal-fin spine below 36th-37th dorsal-fin rays; anus below 35th-36th dorsal-fin rays; anteriormost tip of supraoccipital well posterior to posterior distal margin of eye; anterior margin of the pectoral-fin spine non-serrated; fangs on both jaws with barb-like processes; upper jaw long, mean 16.6% (15.5-17.6%) of preanal length; snout short, 12.0% (10.9-13.1%) of preanal length; eye small, diameter 5.3% (4.3-5.7%) of preanal length; and absence of hyperostosis on dorsal cranium. We herein propose the name Trichiurus javaensis sp. nov., and provide a formal morphological description and diagnostic characterization of this species.
Osvath, G.; Denes, A. L.; Kovacs, Z.; Birau, A. C.; Papp, E.; Jako, G. V.; Zeitz, R.
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Romania represents one of the few European Union member states in which all four Old World vulture species historically maintained breeding populations: the Griffon Vulture (Gyps fulvus), Cinereous Vulture (Aegypius monachus), Egyptian Vulture (Neophron percnopterus) and Bearded Vulture (Gypaetus barbatus). Until the 2026 reintroduction efforts initiated by Foundation Conservation Carpathia and Rewilding Romania, Romania remained the last EU country whose former vulture guild had not been targeted for active recovery. Despite this exceptional significance in a European conservation context, no comprehensive synthesis of the historical and contemporary distribution of these species in Romania has been undertaken. We conducted a comprehensive review to gather all available vulture occurrence data and present a fully georeferenced database of 1,170 occurrence records spanning 1818-2025. We systematically searched museum collections, historical ornithological literature, modern field surveys and citizen-science platforms. The database documents substantial breeding populations across the Carpathian arc and Dobrogea until the early twentieth century, followed by near-total breeding collapse between the 1920s and 1960s driven by persecution, secondary poisoning and agrarian transformation. In total, 149 confirmed or probable breeding records have been documented for the four species combined, with the most recent confirmed breeding records dating to 1929 (Gyps fulvus), 1929 (Gypaetus barbatus), 1942 (Aegypius monachus) and 1966 (Neophron percnopterus). Non-breeding occurrences increase markedly after 2010, consistent with dispersal from expanding Balkan source populations. The F[a]g[a]ra {square} and Retezat Mountains emerge as the historically most important breeding strongholds for all four species. Our dataset constitutes the most detailed historical baseline currently available for vulture conservation in Romania and is intended to identify key historical sites with high potential for future reintroduction and recovery. Our results show that Romania historically supported the full guild of European obligate scavengers, and that its collapse occurred within barely four decades (1920s-1960s). The dataset highlights the value of reconstructing historical baselines in regions where functional extinction preceded the onset of modern monitoring, and provides an empirical foundation for reassembling a keystone scavenger guild at a continental scale.
Ritson, J. P.; Bell, B.; Worrall, F.; Evans, M.; Lindsay, R.; Evans, C.
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O_LICalluna vulgaris is often managed in the UK by rotational burning, but this practice has recently been banned on peat with depth greater than 30-40 cm. It is unclear how then to manage the large areas of Calluna on blanket bogs used for sport shooting because without managed burning, fuel loads and wildfire risk will increase as the Calluna ages within the artificially narrow age distributions created by burn management. C_LIO_LIWe developed a model of Calluna mortality and management to understand duration and persistence of post-management effects. This allows us to assess how long it will take to reach a more natural age structure which would allow increased diversity if management ceases. C_LIO_LIOur results show that management effects persist for around 50 years depending on site-specific mortality rates. Active management may therefore be needed either to mitigate the elevated risk of severe wildfire or to speed up this transition. C_LIO_LISome studies have employed, as unmanaged analogues, Calluna stands that were last managed <50 years ago, but such studies may have unintentionally biased their results by observing Calluna still in post-management recovery leading to an over-estimation of wildfire risk associated with more natural blanket bogs. C_LIO_LISynthesis and applications: with the banning of burning as a management tool for Calluna on deep peat, alternative management is now likely needed as our model shows it could take around 50 years for the Calluna to reach a more natural age distribution. Mowing can replicate some of the effects of managed burning but requires repeated intervention and may compress the peat surface from repeated machine tracking. Rewetting and Sphagnum reintroduction may offer a more sustainable management approach to lowering Calluna fuel loads and reducing severe wildfire risk by creating wetter sub-optimal conditions for Calluna growth and thereby altering the competitive balance between Sphagnum and Calluna. Further work is needed to assess the efficacy of rewetting in controlling fuel loads and how this varies with climate and local pressures. More broadly, this work highlights the need to quantify the persistence of past management regimes to understand ecological trajectories. C_LI
Akoglu, I.; Bacak, E.; Bilgin, S.; Boyla, K. A.; Duran, M.; Akcay, C.; Ertor-Akyazi, P.
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Passive acoustic monitoring poses an immense potential to assess avian diversity in many habitats, including agricultural landscapes. At the same time, automated recorders generate large datasets which present a challenge for processing and effectively assessing biodiversity. Methods such as manual listening by experts, automated detection algorithms like BirdNET and calculating acoustic indices all present different trade-offs in assessment of biodiversity through passive acoustic monitoring. In the present study we recorded soundscapes in a low-intensity agricultural landscape in western Turkiye in all four seasons. Two expert ornithologists listened to a subset of these recordings identifying bird species from the recordings. We also ran the same sample of recordings on BirdNET to compare BirdNET detections with expert detections and calculated acoustic indices for each recording. The results showed that BirdNET detected more species than experts, although some may not be reliable detections. Two acoustic indices (bioacoustic index and acoustic complexity index) were correlated positively with number of species detected by experts and one (normalized difference soundscape index) with number of species detected by BirdNET but the correlations were modest. The results show that acoustic indices may have limited value in detecting biodiversity and automated detection algorithms may do a better job, although these may need to be trained with local data to improve detection and classification.
Moriguchi, Y.; Kimura, S. S.; Kume, M.; Takagi, J.; Uno, Y.; Kanoh, J.; Mitamura, H.
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Telomere length (TL) is increasingly used in ecology as a biomarker of individual quality and environmental stress, yet research on non-model species with complex life histories remains limited. Because TL varies among tissues and across ages in a species-specific manner, identifying non-lethal tissues that reliably reflect whole-organism telomere dynamics is essential for longitudinal telomere studies in the field. This study aimed to evaluate tissue-specific TL in Japanese eel (Anguilla japonica), an endangered catadromous fish. We first mapped the chromosomal distribution of telomeric sequences using fluorescent in situ hybridization (FISH), the first application of this method in this species. We then tested whether muscle and caudal fin, which can be sampled easily and non-lethally, can serve as suitable proxy tissues for TL measurements in wild individuals. Relative telomere length (RTL) was quantified by qPCR in blood, brain, caudal fin, gonads, heart, liver, and muscle. FISH analysis confirmed telomeric repeats at all chromosomal ends, with only weak interstitial signals on three chromosomal pairs unlikely to affect qPCR-based estimates. A generalized additive mixed model and Wilcoxons signed-rank tests revealed significant inter-tissue differences: RTL was shortest in the brain and muscle and longest in liver, blood and caudal fin. Muscle and caudal fin RTL were significantly correlated with RTL in many other tissues, supporting their use as proxy tissues for longitudinal TL monitoring, including responses to environmental variation. Both total length and age were tested as explanatory variables for RTL, and the model including total length showed a better fit than the age-based model. Non-linear relationships between RTL and total length observed in several tissues suggest physiological shifts associated with growth and sexual differentiation. Overall, these findings advance understanding of telomere dynamics in eels and establish muscle and caudal fin as suitable tissues for repeated, non-lethal TL assessment in ecological and conservation contexts.
Lam, H.; Lin, S.; Xu, Z.; Yau, C. S. T.; Wu, L.
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For over four decades, the bivalve Anomalocardia flexuosa has been recorded in Hong Kong coastal waters. However, the known native distribution of this heavily exploited commercial species is restricted to the Atlantic coast of South America, raising questions about the biogeographical validity of the Hong Kong populations. By employing an integrative taxonomic approach combining morphological re-evaluations and molecular phylogenetic analysis of the COI gene, we confirm that the species in Shui Hau, Hong Kong, China, has been historically misidentified. The population belongs to Cryptonema producta (syn. Anomalocardia producta).
Rohrlack, T.
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The prevalence of nitrogen limitation and nitrogen-phosphorus co-limitation (henceforth referred to as nitrogen-related limitation) in Norwegian lakes and their relationships with atmospheric nitrogen deposition, climate, dissolved organic matter (DOM), and catchment characteristics were assessed across space and time. Routine monitoring data from 1,529 lakes in the national Vannmiljo database were analyzed for two multi-year periods (1995-2009 and 2010-2025). Limitation was inferred using the molar NO--N/TP ratio as an indicator of dissolved inorganic nitrogen availability. Nitrogen-related limitation was widespread in both periods and exhibited strong regional structure, with highest prevalence in northern regions and lowest prevalence in southwestern Norway. Overall prevalence increased from 31% to 38% between periods, with significant increases in western regions. Regional-scale models identified climate, forest cover, DOM, agriculture, and atmospheric nitrogen deposition as predictors of limitation probability, whereas study period per se and bog/peatland cover were not significant. At the local scale, atmospheric nitrogen deposition and DOM were the only consistent predictors, with substantially lower explanatory power than at the regional scale. These results indicate that large-scale environmental gradients play a major role in shaping nutrient stoichiometry in Norwegian lakes. Because the monitoring dataset primarily represents lakes affected by human activities, the findings are particularly relevant for water management. The widespread occurrence of nitrogen-related limitation suggests that nitrogen availability may influence phytoplankton growth in many systems and that dual-nutrient management strategies addressing both nitrogen and phosphorus may be required in many regions.
Simmons, R. E.; Martins, M.; Peralta, F. C.
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Avian collision rates are certain to rise as renewable energy industries roll out wind and solar farms to reduce fossil fuel impacts in biologically diverse areas of the world. Technological solutions are often sought to decrease mortality rates, but for developing nations automated shut downs are expensive, and alternatives required. A promising route is to increase blade visibility to birds using high contrast colours. Despite the success of the solid black-blade experiment in Norway only one other black-blade field-study in the Netherlands has explored this possibility, with no significant results. We tested the use of colour-patterned blades at a species-rich, 37-turbine, wind facility in Hopefield, South Africa. Two broad "signal red" stripes were applied to a single blade at four high-fatality turbines, in 2023 by Umoya Energy. Avian fatality rates were compared before and after painting using the Before-After-Control-Impact (BACI) approach. Seventy-five fatalities of 23 species of raptors, passerines and wetland species over 24 months were compared for the same 20 turbines after patterning with two sets of controls: (i) their four nearest neighbours (NN) and (ii) all 16 controls (AC). Over 32 months 25 fatalities were recorded, 23 occurred at the controls and only two at the patterned turbines. Testing with Bayesian Generalized Linear Models (BGLMs) revealed a median 83% reduction in fatalities at the patterned blades for both the NN turbines (credible intervals 14% - 98%) and the AC comparisons (30% - 97%). Bayes Factors (BF) revealed strong statistical support for NN (BF = 49.9) and AC comparisons (BF = 159). There was little evidence that birds avoiding patterned turbines increased fatalities at the neighbouring turbines as there was a small median 15% increase in fatality rates when NN controls were compared with other controls, and weak statistical support (BF = 0.15). Among 14 raptor species recorded on site, 10 species have suffered fatalities. Of seven individuals killed prior to treatment at the four patterned blades, only one was killed post-treatment suggesting blade patterning is equally effective at reducing raptor fatalities. Our results show that patterned blades had a high probability (83%) of reducing fatalities with strong statistical support despite the small samples. This supports the Norway experiment in a high diversity African setting, but with red patterns not a solid black design. The strong effect of red stripes may arise from both the high contrast it provides and the possible warning effect that red may elicit. We call for additional experiments to differentiate the effect of patterns and colours for the optimal design to reduce avian-turbine collisions.
Avila-Thieme, M. I.; Martinez, K.; Olivero, H.; Tejo, M.; Videla, L.; Navarrete, S. A.; Marquet, P.; Donlan, J.; Gelcich, S.; Rebolledo, R.
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Non-compliance with regulations threatens the sustainability of fisheries worldwide. Understanding the interconnected feedbacks of this complex social-ecological problem is key for sustainability but rarely integrated into fisheries management. We provide an adaptive stochastic modelling framework that integrates economic, social behavior, and ecological aspects of the Chilean kelp fishery, which plays a critical economic and ecological role in coastal social-ecological ecosystem. High levels of non-compliance is threatening sustainability, fishers well-being, and ecosystem health. Our model considers inherent environmental uncertainties and enables the assessment of different harvesting and compliance scenarios and the role of market-based economic incentives in reducing non-compliance. Results show that, unlike the sustainability obtained under an idealized full-compliance scenario, under dynamic compliance the social, economic, and ecological feedbacks leads to system collapse. Importantly, price premiums can promote compliance and sustainability, but the probability of collapse, albeit small, still exist. Our generalizable stochastic modeling framework evidenced that accounting for inherent uncertainty in natural resource management is key to designing interventions for sustainability.
Sage, R. B.; Bealey, C.; Woodburn, M. I. A.; Werling, J.; Banks, A. N.; Abrahams, D.; Madden, J.
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The release and management of pheasants (Phasianus colchicus) in the UK for recreational shooting exerts a range of effects on the ecosystem into which they are released. We studied possible effect of nutrient deposition on epiphytic tree flora at 20 pheasant release sites distributed through England (18) and Wales (2) during winter and spring 2023/24. Sites were all Ancient Semi-natural Woodlands (ASNWs) and had substantial (600-8000 pheasants) in a single release pen. We measured N-sensitive and N-tolerant indicator bryophyte and lichen species on tree trunks near to the pen and then in plots along a transect 100m, 250m, 500m and 1km+ away from the pen. To achieve a gradient of pheasant use, the transects were located in the opposite direction to the game managed / shooting area. We recorded 1.9 times more coverage of N-tolerant lichens and bryophytes combined on selected tree species at the pen-edge compared to the control plots. The relationship showed a decline from the pen edge to 250m away but then stabilised. We also detected higher levels of coverage of N-sensitive tree flora at 100m and 250 m compared to the penedge plot. These measures were also higher at these mid distances compared to the 500m and 1000m plots. We suggest far plots were nearer wood edges and were affected by ambient inputs of aerial N from farmland and other external sources. The overall interpretation is that concentrations of pheasants in and around release pens for several months from late summer until early winter in ASNWs does affect the balance of N-sensitive and tolerant tree flora up to potentially 250m and this is a consideration when locating release pens in and near to sensitive woods.
Lashley, M.; Leipold, E.; McDonald, B.; Baruzzi, C.
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Wildlife feeding during the wild turkey (Meleagris gallopavo) hunting season is legal in many states within the United States, but hunting turkeys with the aid of bait is unlawful in most states. The most common policy to prevent wildlife feeding from acting as bait is to restrict hunting within a defined radius. However, the effect of wildlife feeders on turkey harvest risk and the effectiveness of distance restrictions on mitigating that influence have not been investigated. During 2024-2025, we used GPS transmitters to track 30 adult male turkeys during the spring hunting season on private land with active feeders in Florida, USA, where hunting turkeys within a 91 m radius of a feeder was unlawful. We used Cox proportional hazard models to link risk of hunter harvest with unique feeders visited daily, number of feeders within a home range, and average morning distance and roosting distance to feeders at multiple temporal scales. Hunters harvested 53% of the tagged turkeys. Risk of hunter harvest increased with the number of unique feeders visited the previous day and after the first three days of hunting season with the number of active feeders within a home range. As distance from the most recent roost site and average morning distance to a feeder decreased, risk of hunter harvest increased. We estimated that risk of hunter harvest would be reduced by over 50% if distance restrictions were increased from 100 m to 200 m, by nearly 75% with an increase from 100 m to 300 m, and by nearly 90% with an increase from 100 m to 500 m. To completely eliminate the influence of wildlife feeders on risk of hunter harvest would require a restriction distance well beyond a 500m radius, which is impractical given that this radius would result in an area twice the average private landowner property size in the region. Thus, if wildlife feeding during the turkey hunting season is to be allowed, it will act as bait, in which case, the acceptable level of its influence as bait can be achieved with the appropriate hunting radius restriction.