Elasmobranchs play a major role in shaping the structure and functioning of marine ecosystems through their position in food webs. The Lusitanian cownose ray Rhinoptera marginata, a benthopelagic species classified as Critically Endangered on the IUCN Red List, is frequently landed in fisheries off the Mauritanian coast, yet its trophic ecology remains poorly documented. We investigated the diet of R. marginata along the coast of Nouadhibou through stomach content analysis of 308 individuals sampled between March 2022 and August 2023; 135 stomachs (66 females and 69 males) contained identifiable prey and formed the basis of the analyses (disc width range 33–87 cm). Common dietary indices (frequency of occurrence, numerical and gravimetric percentages, Pinkas’ IRI, Hureau’s Q) were combined with multivariate approaches (PERMANOVA on Bray–Curtis dissimilarities, SIMPER, non-metric multidimensional scaling), measures of trophic niche breadth and specialization (Levins’ standardized index Bi, Shannon H′, Pielou’s J′, modified Costello plot), niche overlap (Pianka and Schoener indices), and ontogenetic modelling (generalized additive models). A total of 33 prey taxa were identified, dominated by Bivalvia (86.1% IRI), followed by Gastropoda (6.9%) and Crustacea (6.7%). The species exhibited a strongly specialized feeding strategy (Levins Bi = 0.06; Shannon H′ = 1.42) with high niche overlap between sexes (Pianka = 0.89). PERMANOVA detected significant compositional differences across seasons (pseudo-F = 6.98, p < 0.001) and size classes (pseudo-F = 4.98, p < 0.001) but not between sexes (pseudo-F = 1.87, p = 0.077). The proportion of bivalves significantly decreased with body size (R2 = 0.176, p < 0.001), revealing a clear ontogenetic shift towards more diversified prey in larger individuals. The estimated trophic level (3.13) confirms a mesocarnivore benthic position. These results provide the first comprehensive description of the diet of R. marginata in West Africa and highlight its role as a specialized durophagous predator of bivalve molluscs, omnipresent along the northern Mauritanian coastal ecosystems. By identifying the principal prey, our findings provide a basis for identifying potentially important foraging habitats for this Critically Endangered species and informing future conservation and management strategies.
Synthetic multi-species consortia provide valuable insights into the ecological and structural dynamics of complex microbial biofilms. However, the specialized functional contributions of individual components under severe nutrient limitations remain poorly understood. This study investigated the population dynamics, matrix biogenesis and metabolic potential of a synthetic ‘protolichen biofilm’ model comprising Asterochloris microalgae, Gordonia bacteria, Thelebolus filamentous fungi and Occultifur yeast. The biofilms were cultivated under strict carbohydrate-deficient conditions for 30 days. Population changes, extracellular polymeric substance (EPS) matrix formation, and the concentrations of extracellular DNA (exDNA) and proteins (exProt), as well as potential dehydrogenase activity (via iodonitrotetrazolium reduction), were evaluated across monocultures, binary, ternary and quaternary consortia. Under carbon starvation, the photoautotrophic microalgae dominated the consortium, driving an 11-fold increase in population size in the four-component system and serving as the primary source of exDNA, which increased by up to three orders of magnitude by day 30. The Gordonia sp. exhibited a tenfold expansion by actively localizing to fungal hyphae and microalgal cell walls. This was directly correlated with a sharp increase in metabolic activity. By contrast, Thelebolus sp. initially provided the structural framework via EPS production, but exhibited limited metabolic activity over time. Meanwhile, the Occultifur sp. yeast population was severely suppressed, adopting a sit-and-wait ecological strategy. Spearman correlation analysis revealed that multi-species integration stabilized the community and triggered significant emergent effects in exDNA accumulation and metabolic potential, but only when microalgae were present. These findings demonstrate that microalgae and bacteria primarily drive metabolism and regulation within the protolichen consortia investigated, while fungi and yeast play structural or opportunistic roles. This provides a robust framework for understanding complex symbiotic interactions.
Ecological research on alpine plant communities (snow-bed grasslandnd alpine tundra) has been continuously conducted over the last 33 years at the Velino–Duchessa Long-Term Ecosystem Research (LTER) site in the Central Apennines. Following the Long-Term Ecosystem Research network’s distinctive integrated and ecological approach, researchers analyze biotic components at fine scale using phytosociological relevés. Monitored abiotic parameters include air and soil temperatures, rainfall, snowfall, snow cover persistence, and soil chemistry. Separately for both plant communities, we tested changes in taxonomic diversity (species richness and Shannon diversity) and functional composition (proportion of life form, morpho-functional types, Grime’s strategies, root types, and root depth) using descriptive statistics and generalized additive mixed models. Ecological changes due to increasing water and snow cover deficiencies arise in both plant communities, with 30% change in species composition per year. By contrast, there was no significative change in the total number of plant species, some sensitive species completely disappeared, and a number of invader species appeared, with a rise in more thermophilic and drought-tolerant species and a decline in more mesic and cryophilic species. Climate change in the Apennines, with a strong reduction in the duration of snow cover and an increase in the mean and minimum annual temperatures in the mountains, could be linked to these ecological changes.
Riparian land use and land cover (LULC) exerts scale- and season-dependent controls on surface water quality, yet its influence in regulated agricultural–urban rivers is poorly characterized. We combined seasonal t-tests, one-way ANOVA, and redundancy analysis (RDA) at three riparian buffer scales (500, 1000, and 2000 m) to examine discharge, dissolved oxygen (DO), temperature, turbidity, and pH at four USGS stations along the Kansas River mainstem (2019–2026). DO and temperature showed the strongest seasonal contrasts: DO was 3.1–3.7 mg/L higher in the dry season and temperature 13–15 °C higher in the wet season, a coupling central to aquatic habitat suitability. Turbidity rose significantly in the wet season, consistent with agricultural runoff and sediment mobilization, whereas discharge showed no significant seasonal difference at three of four stations, reflecting upstream reservoir regulation. Spatial ANOVA detected station-level differences only for wet-season DO (F3,28=4.91, p=0.007), which was lowest at the downstream urbanized station. RDA linked agricultural cover to turbidity and urban cover to reduced wet-season DO, although permutation tests were non-significant (p≥0.42) at n=4 replicates. Seasonality and riparian LULC jointly shape water quality along this regulated river, and the 500 m buffer is the most spatially discriminating scale for land-cover assessment.
Environmental change is reshaping ecological communities, yet conservation efforts often continue to focus on protecting species rather than the interactions that sustain biodiversity. Butterfly–plant interaction networks include well-studied systems that are an important component of biodiversity and can be foundational for examining how ecological relationships respond to climate change, habitat alteration, species introductions, restoration, and conservation management. Most studies of these interactions rely on observational records, plant use data, pollen load evidence, and historical specimens to reconstruct how butterflies use plant communities and how these relationships vary across environmental contexts. However, these studies remain scattered across disparate ecosystems, and network data have not been integrated to explain how butterfly–plant interactions are reorganized under environmental change. Here, we synthesize the literature to evaluate how butterfly–plant interactions are reshaped by environmental change in the United States. The evidence indicates that the most impactful environmental change drivers include: increases in temperature, drought, extreme weather, habitat fragmentation, land use change, species introductions, and conservation interventions. These environmental change parameters alter butterfly–plant interactions through partner shifts, temporal mismatch, reduced plant resource diversity, altered plant availability, weakening of specialized links, and increased reliance on generalist plant species. Strong shifts in butterfly–plant interactions may occur even when butterfly and plant species remain present and even abundant, making interaction loss an early signal of ecological change. A network perspective is useful because it can reveal whether specialized or rare butterfly–plant links persist or whether environmental stress shifts communities toward interactions in which butterflies utilize fewer widely used plant resources or plants are reliant on fewer species of butterflies. By integrating observational evidence, historical specimen-based pollen records, restoration contexts, and network analysis, this review provides an interaction-centered framework for understanding and conserving butterfly–plant relationships in changing environments, with implications for ecological sustainability.
Water hyacinth has become a major environmental problem in aquatic ecosystems worldwide, including Indonesia, due to its rapid growth and extensive surface coverage. Transforming this invasive biomass into high-quality compost offers a sustainable solution for biomass management and agricultural utilization. However, information regarding the combined effects of decomposer selection and the compost aeration process on compost quality, nutrient transformation, and agronomic performance remains limited. This study was conducted in Rawa Pening, Central Java, Indonesia, to determine how decomposer type and turning regime (specifically the frequency and method of mechanically aerating the compost pile) influence the quality of water hyacinth compost and to identify the most suitable formulation for pak choi (Brassica rapa L.) growing media. The experiment consisted of four sequential stages: composting, compost quality assessment, compost selection, and plant growth bioassay. Three decomposers (EM4™, cow dung, and Stardec™) were evaluated under turning and no-turning conditions using a factorial completely randomized design. Compost quality was assessed based on physicochemical characteristics, nutrient composition, compost yield, and correlation analysis. The best compost treatment was subsequently evaluated in different soil–compost mixtures using ANOVA, PCA, and correlation analysis. The results demonstrated that turning and decomposer selection acted synergistically to determine compost performance. Cow dung consistently produced the highest compost yield, whereas Stardec™ combined with turning generated the most mature compost, characterized by the lowest C/N ratio and the highest nitrogen and phosphorus contents. Plant bioassay confirmed that the optimal growing medium consisted of 50% soil and 50% compost, which maximized vegetative growth by balancing nutrient availability with physical support for root development. No toxicity symptoms were observed, indicating that mature water hyacinth compost is safe for agricultural use. These findings provide practical guidance for selecting decomposers based on compost production objectives and promote the sustainable utilization of invasive water hyacinth.
The rapid recovery of wildlife populations can outpace the assumptions of integrated population models and make visually plausible reconstructions difficult to distinguish from diagnostically supported inference. We evaluated this problem for Kazakhstan saiga antelope (Saiga tatarica) using a Bayesian model-ladder sensitivity audit for the Betpak-Dala, Ustyurt, and Ural populations from 1980 to 2025. We fitted a climate-aware, age- and sex-structured baseline model family M0 (climate-aware static-K baseline comparator) and compared it with dynamic carrying-capacity, observation-regime, hierarchical-prior, joint-hierarchical, non-centred, and sampling-optimised development families using predefined-convergence, effective-sample-size, posterior-predictive, and observed-to-latent mismatch gates. The baseline reconstruction captured the broad collapse–recovery dynamics but systematically underpredicted the observed abundance in 2021–2025 across all three populations. The strongest development family M4b R2 (sampling-optimised joint-hierarchical development family) improved the R-hat values and late-series alignment, with 2025 observed-to-latent ratios of approximately 1.77, 1.43, and 1.49 for Betpak-Dala, Ustyurt, and Ural, respectively, but the effective sample sizes remained below the gate of 400. The study therefore provides a transparent diagnostic reconstruction and model-development audit rather than management-ready Bayesian integrated population model (IPM) inference, identifying where the current baseline fails and which structural directions require further validation.
Early establishment is a critical filter in restoration plantings, especially when seedlings must face seasonal water limitation after outplanting. This study evaluated whether nursery-derived functional trait profiles are associated with early field performance of Pinus devoniana Lindl. seedlings in restoration plantings. Six profile codes were built from contrasting combinations of rooting space, nutrient supply, and water regime. Seedling traits were grouped into structural development, belowground investment, allocation quality, nutritional status, stress expression, and field establishment. Functional scores were calculated from standardized variables, and profile responses were examined through conservative comparisons, descriptive principal component analysis, and trait–performance associations. The large-rooting-space, fertilized, continuously irrigated profile (LFI) showed the most balanced pattern, combining positive structural development, high belowground investment, favorable allocation quality, low stress expression, and the highest survival. The large-rooting-space, fertilized, reduced-irrigation profile (LFR) reached the highest field establishment score, but this response was accompanied by stronger stress expression. The large-rooting-space, non-fertilized, reduced-irrigation profile (LNR) had the highest nutritional status, although this did not translate into superior establishment. Under the evaluated conditions, larger rooting space and coordinated belowground investment, allocation quality, and low stress expression were most consistently associated with better early field performance.
Ecological niche modeling (ENM) is widely used to predict species distributions and support biodiversity conservation under environmental change, yet its application to Amazonian wetland plants has not been systematically synthesized. We conducted a systematic review following the PRISMA 2020 guidelines to evaluate methodological approaches, environmental predictors, model performance, and research gaps. Literature searches were performed in Web of Science, Scopus, and Consensus (as a complementary AI-assisted academic search platform), yielding 1789 records, of which 48 met the eligibility criteria. Correlative models predominated, with MaxEnt, Random Forest, and ensemble frameworks being the most frequently applied algorithms. Across studies, integrating hydrological and edaphic predictors consistently improved model performance and ecological realism compared with climate-only approaches. Future climate projections indicated greater vulnerability for habitat-specialist species, whereas western Amazonia and the Andean foothills were repeatedly identified as potential climatic refugia. Major limitations included geographically biased occurrence records, limited high-resolution environmental datasets, and the underrepresentation of several Amazonian wetland ecosystems. Overall, the evidence indicates that reliable ENMs for Amazonian wetlands require integrating climatic, hydrological, and edaphic drivers rather than relying solely on macroclimate. Future research should prioritize geographically representative sampling, improved environmental datasets, transparent workflows, and process-informed modeling to strengthen ecological forecasting and conservation planning under climate and land-use change.
Background: Population sex ratios and age structure are fundamental demographic parameters in shorebird studies, and their accurate estimation depends on unbiased capture methods. Methods: To identify potential capture biases, we evaluated the randomness of mist-net recaptures between sex and age classes of the Western Sandpiper (Calidris mauri) in La Paz Lagoon, Baja California Sur, Mexico. Results: A total of 856 individuals were captured and banded, of which 89 (10.4%) were recaptured. Observed and expected recapture frequencies did not differ significantly between sexes (67 observed vs. 62 expected males; 22 observed vs. 26 expected females), indicating no sex-related bias in recapture probability. In contrast, significant differences were detected between age classes (20 observed vs. 42 expected adults; 69 observed vs. 46 expected juveniles), demonstrating a clear age-related bias. The elapsed time between initial capture and recapture was similar for males and females but differed significantly between age classes: adults were most frequently recaptured after 51–75 days, whereas juveniles were recaptured predominantly after 1–25 days. Conclusions: Juveniles were more likely than adults to be captured and recaptured. The higher capture probability of juveniles may be associated with their greater mobility, resulting from their limited experience and lower social status.
Information on factors influencing fitness, flowering, and fruit production in Cyclamen species remains limited. This study evaluated these traits throughout the growing season in three populations of Cyclamen purpurascens subsp. immaculatum under contrasting environments: a young beech forest (half-shade), an old beech forest (shade), and an open meadow. Because this protected endemic taxon of the Western Carpathians (Ve & lcaron;k & aacute; Fatra and Starohorsk & eacute; vrchy Mountains, Slovakia) cannot be sampled destructively, we used in situ observations and chlorophyll a fluorescence measurements. We found seasonal variation in photosystem II (PSII) efficiency and high environmentally driven inter-individual variability. Plants in the meadow exhibited significantly lower values of Fv/Fm, Fm/F0, and Area parameters, likely reflecting combined microclimatic stress. These plants also produced significantly fewer flowers, suggesting reduced resource availability for reproduction. In contrast, no significant differences in fluorescence parameters were detected between the two forest habitats, which showed similar seasonal dynamics. However, plants in the young forest produced the most flowers and slightly more fruits than those in the old forest or open meadow. Overall, our results suggest that meadow habitats may be less suitable for this taxon, while old-forest environments are tolerated but may reduce reproductive output. Semi-shaded forest habitats may be important for long-term persistence of this taxon.
The Biological Monitoring Working Party (BMWP) and Average Score Per Taxon (ASPT) indices, which rely on family-level environmental sensitivity values (FESVs), are widely used in freshwater bioassessment. However, regional differences in taxonomic composition often render existing FESV systems incomplete or incompatible, and the influence of rare families remains poorly understood. Using a historical dataset from the temperate Taizi River basin in Northeast China, we developed a regional FESV system for benthic macroinvertebrates. A total of 67 FESVs were established, including 10 families not previously scored in the UK system. These values followed a normal distribution and were ecologically validated using canonical correspondence analysis (CCA). Both BMWP and ASPT indices showed significant correlations with water quality parameters, the Water Quality Index (WQI), and the Habitat Quality Index (HQI). Notably, excluding rare families (occurrence frequency < 1%) did not reduce but slightly enhanced the responsiveness of both indices. CCA identified HQI, conductivity, and ammonia nitrogen as the primary drivers of community composition, and the inferred ecological preferences aligned well with the assigned FESVs. This study provides a robust, regionally adapted framework for family-level bioassessment in temperate East Asian rivers and supports the exclusion of rare taxa to improve cost-effectiveness and index sensitivity.
The yellow mealworm (Tenebrio molitor, Linnaeus) is a cosmopolitan pest of stored grains, causing losses up to 15%. Due to the environmental and health risks of synthetic fumigants, botanical alternatives are needed, but their ecotoxicological assessment is also required. Thus, the aim of this study was to assess the insecticidal, insectistatic, and ecotoxicological effects of Salvia connivens (Epling) dichloromethane extract and to identify its compounds. Insecticidal and insectistatic activities were assessed through the consumption of an artificial diet containing the extract over 30 days. Ecotoxicological activity was evaluated through acute toxicity assays on Danio rerio (Hamilton) adults and embryos. The extract showed insecticidal activity against T. molitor achieving 50% mortality at 10,000 ppm (LC50 = 9367.19 ppm). Additionally, at 10,000 ppm larval weight gain was reduced by 53.37% at 30 days compared to the control. Ecotoxicological assays revealed slight toxicity toward D. rerio adults (LC50 = 84.27 ppm) and embryos (LC50 = 32.60 ppm). GC-MS analysis identified hexadecanoic acid (7.08%), 1-(2-methoxyphenyl)-2,5-dihydro-1H-pyrrole-2,5-dione (6.30%), cis-9-octadecenoic acid (3.91%), beta-sitosterol (3.05%), and eicosane (3.00%) as the major constituents according to the chromatographic method used. These findings suggest that S. connivens dichloromethane extract is a potential botanical product for T. molitor management.
The daily activity patterns of wild animal species are driven by environmental conditions and plant productivity although the degree of dependence varies according to their ecological niche. Bear ecology is intrinsically linked to seasonal vegetative availability. As omnivores with high metabolic demands, these species rely heavily on botanical resources including fruits, seeds, and roots. Consequently, differences in primary productivity across the landscape influence how individuals distribute their circadian activity patterns. The Enhanced Vegetation Index (EVI) is a tool that quantifies the quality and vigor of vegetation. Relating the EVI to activity patterns allows us to understand how vegetation dynamics and conditions influence the use of time at different times of the day. This study analyzes the daily activity pattern of the American black bear (Ursus americanus) in the El Cielo Biosphere Reserve (ECBR) using camera traps and its association with spatial variations in the Enhanced Vegetation Index (EVI). The results show that the daily activity pattern of the American black bear in the ECBR exhibits a diurnal-crepuscular tendency. In areas with high primary productivity and higher temperatures, activity occurs before sunrise and at sunset, with low activity during the rest of the day. In contrast, in areas with less vegetation and lower temperatures, activity occurs throughout the day. This suggests that, in the ECBR, the activity pattern of black bears could be modulated by temperature variations related to changes in vegetation productivity.
The Shymkent-Saryagash-Abay (A-15) international highway is a major Kazakhstan-Uzbekistan freight corridor that runs through the irrigated horticultural belt of the Turkestan Region in South Kazakhstan, where adjacent fields supply vegetables and cucurbits to the regional market. Composite soil samples (n = 18) were taken at six distances (2-300 m) from the road edge across three locations during 2022-2023, along with edible fruits of tomato, cucumber, watermelon, and melon (n = 12) from the adjoining fields. Pb, Zn, and Cd were measured via flame atomic absorption spectrometry after HNO3/H2O2 digestion. Soil concentrations decreased sharply with distance (Pb: 26.3 -> 5.98 mg kg(-1); Zn: 21.29 -> 4.16; Cd: 0.47 -> 0.01 mg kg(-1)), exceeding the national soil MPCs by 1.5-3 times within 2-10 m. Pb and Zn exceeded the Kazakhstani food-safety MPCs in all four crops, and Cd in three of four (tomato, cucumber, and melon). Transfer factors followed the order of Cd (2.90-4.40) > Zn (1.99-3.00) > Pb (0.16-0.30), and the Cd geo-accumulation index ranged from 1.05 to 1.65 at 2-5 m. Adult dietary risk was acceptable (HI = 0.029-0.052; CR < 1.7 & times; 10(-6)), yet food-safety exceedances support a precautionary sanitary buffer and combined soil-and-crop monitoring along the corridor.
Wetlands are ecosystems with critical functions. However, the accelerated progression of global urbanization and human activities, including agricultural encroachment, has resulted in a notable decline in wetland areas and the degradation of wetland quality worldwide. Consequently, wetland restoration has become a central focus of wetland research. Plant community characteristics are among the simplest and most frequently used indicators for evaluating wetland restoration progress and are a crucial factor in maintaining the health and stability of wetland ecosystems. Therefore, this study aimed to investigate the plant community characteristics of restored wetlands with different durations of abandonment in the lower Tumen River Basin, which is expected to provide guidance for promoting the restoration of abandoned farmlands in this region. We hypothesize that species diversity decreases with increasing abandonment age, plant community composition converges toward that of natural wetlands over time, and beta diversity declines due to increasing biotic homogenization during succession. We established a chronosequence of abandoned wetlands in the lower Tumen River Basin, with sites abandoned for approximately 5, 15, and 30 years. And we use natural wetlands and paddy fields as references. With natural succession, the dominant plant species in the restored wetlands transitioned from annuals/biennials to perennials. The aboveground biomass initially increased and subsequently decreased. A gradual decline in species diversity was observed along with a further reduction in beta diversity, and the species turnover component consistently exceeded the richness difference component. The pronounced biotic homogenization among communities indicates that achieving a stable state comparable to that of natural wetlands may require considerably more time or may not be attainable solely through natural succession.
Dozer lines can play a key role in the containment of a wildfire; they can also result in long-lasting impacts to vegetation and soils. Despite this, their post-fire ecological impacts are understudied. I assessed vegetation recovery associated with 29 dozer lines within five wildfires that burned between 2018 and 2021 across the Klamath Mountain ecoregion in northern California. Sampling occurred between one and five years post-fire along transects beginning within and extending out 30 m from the dozer line. Vegetation recovery was lowest within the dozer line, where average percent cover ranged from 3 to 5% regardless of years post-fire. Non-native species were found across all sites but were not significantly greater in cover within or outside the dozer line compared with native species. Non-native cover was best explained by elevation and canopy cover, where lower-elevation sites with reduced canopy cover had the greatest cover of non-natives. More research should be done to investigate longer temporal trends in non-native cover post-fire near and within dozer lines.
In transitional tropical ecosystems such as the Amazonia-Cerrado ecotone, dominant tree species experience strong environmental heterogeneity, requiring coordinated functional strategies to cope with drought, nutrient limitation, and disturbance. However, how these species integrate leaf morphoanatomical traits and wood density to persist in such environments remains poorly understood. We assessed the coordination among leaf anatomical and morphological traits and their relationship with wood density in five dominant tree species across three savanna park sites in the Amazonia-Cerrado transition. Morphological traits included leaf thickness, specific leaf area, leaf dry matter content, and wood density, alongside 17 anatomical leaf traits. We analyzed inter- and intraspecific variation and covariation patterns to identify trait-based ecological strategies along the acquisitive-conservative spectrum. We found strong coordination among traits related to protection (e.g., cuticle thickness and trichomes) and resource use, as well as clear alignment between leaf and wood traits. Species identity explained most trait variation, although leaf thickness showed notable intraspecific plasticity. Species with conservative traits exhibited thicker leaves and higher wood density, whereas species with acquisitive strategy showed higher specific leaf area and lower leaf dry matter content. Overall, trait coordination reflects integrated ecological strategies shaped by environmental heterogeneity, highlighting the role of multi-trait syndromes in driving functional adaptation in ecotonal systems.
The San Juan Islands are one of the few places where native temperate grasslands are found in western Washington State. These ecosystems are important reservoirs of biodiversity and sources of ecosystem services, support many rare and endemic species, and have profound cultural significance to the Coast Salish peoples. These ecologically and culturally valuable ecosystems have become scarce due to the combined pressures of changes in land use, the introduction of non-native invasive species, and the exclusion of fire from the landscape. A lack of historical context and ecological baseline knowledge has made it impossible to fully understand the long-term trends in the extent and distribution of this ecosystem. To address this knowledge gap, we used historical land cover data and multispectral imagery to create a high-resolution, spatially explicit database of grassland extent on the San Juan Islands at multiple time periods since the early years of Euro-American colonization. Our spatial analysis of these data revealed significant decreases in grassland extent between time periods, with an overall 77% net decrease in the extent of non-agricultural grasslands and a loss of 93% of the area of persistent, old-growth grasslands since 1890 across the region. These changes are primarily a result of conversion to agriculture and conifer encroachment or succession to forest. The spatial data and analyses created in this study help to develop the historical baseline of native temperate grasslands on the San Juan Islands, adding to our understanding of the lingering legacy that changes in land use have had on this ecosystem, with the potential to aid in the development of effective conservation and restoration practices.
Effective management and conservation of sea turtles is often constrained by a lack of knowledge of at-sea distribution and abundance. While abundance estimates of nesting females are typically well-documented on nesting beaches, counting sea turtles at sea presents challenges due to their widespread distribution and cryptic habits. Given nesting beaches only document adult females, at-sea data are also more informative of greater population demographics. To estimate the abundance and density of green sea turtles (Chelonia mydas) in the Red Sea waters of Saudi Arabia we conducted strip transect aerial surveys in four survey zones that spanned similar to 66% of shallow water habitats (<200 m depth), within which we counted sea turtles, and also other species such as dugongs and other marine mammals, sharks, and rays. Corresponding abundance estimates were modelled to account for perception bias (whether a surveyor saw a turtle that was available) and detection bias (whether a turtle was available to be seen). Our results suggest an abundance of similar to 201,427 green sea turtles potentially present between the 200 m bathymetric contour and the Saudi Arabian shore. However, there was a statistically significant relationship between turtle location and proximity to coral reefs, with over 90% of turtles found within 3500 m of coral reef structures (whether coastal fringing reefs, barrier reefs or atolls), and therefore it would be inappropriate to use an estimate assuming equal distribution. Adjusting for this buffer area we estimated similar to 95,000 turtles (95% CI: 64,000-142,000) within the proximity of reef structures. These findings represent the first abundance estimates of green turtles in the Red Sea. Repeated over time, surveys such as these can identify changes in population structure, distribution and abundance, and inform conservation and management agencies.
