Search Results (364)

The conservation of endemic tree species in the Philippines requires lightweight and localized technological solutions. Therefore, we benchmark three Convolutional Neural Network (CNN) architectures: MobileNetV2, EfficientNetB0, and NASNetMobile, using 1800 leaf images from five endangered Dipterocarpaceae species and an unknown class. The models were trained with transfer learning and deployed on a Raspberry Pi prototype. Validation accuracies exceeded 97.00%, with NASNetMobile reaching 99.44%. Field testing produced lower accuracies of 85.00% for NASNetMobile, 77.78% for MobileNetV2, and 66.11% for EfficientNetB0. One-way analysis of variance with Tukey’s Honestly Significant Difference showed no statistically significant differences at the 0.05 level. These findings highlight the importance of field validation and statistical testing in CNN benchmarking for embedded biodiversity monitoring. Full article

Platonia insignis Mart. (Clusiaceae) is a native fruit tree of great ecological and socioeconomic importance in the Brazilian Amazon and Cerrado. However, habitat loss is threatening its genetic variability. We investigated whether habitat fragmentation across the Amazon, Cerrado, and transition zones shapes the genetic diversity and population structure of five natural populations of P. insignis, using ISSR markers. Leaf samples from 13–15 individuals per population were collected, and DNA was extracted using the CTAB protocol. Twelve ISSR primers amplified 149 loci, used to estimate genetic parameters. AMOVA showed that 73.58% of genetic variation occurred within populations and 26.41% among populations (F_ST = 0.261). Amazonian populations exhibited the highest genetic diversity, while transition zone populations had the lowest values. The Cerrado population was genetically distinct and maintained moderate intrapopulation diversity. Bayesian clustering, PCoA, and UPGMA revealed three genetic groups corresponding to the sampled regions. Transitional populations showed high genetic admixture, indicating their role as potential corridors for gene flow. Our results highlight the need to preserve genetically diverse Amazonian populations, safeguard the Cerrado population as an evolutionarily significant unit, and maintain transitional populations to promote landscape connectivity. The study provides a genetic baseline to support conservation and management of P. insignis germplasm resources. Full article

Martagon Lily, Lilium martagon, belongs to geophytes inhabiting mainly forest communities in temperate regions of Europe and Asia and it is considered as a rare and endangered species in many regions. The presented investigations were conducted in three populations, occurring in forest habitats in Southern Poland: Wolski Forest (population 1), Mount Chełm (population 2), and Hrabeński Forest (population 3). At each site, 10 phytosociological relevés covering an area of 100 m² were taken. For each phytosociological relevé, the Shannon–Wiener, Pielou, and Simpson indices, as well as the number of species, were calculated. The detailed field studies were conducted in permanent study patches measuring 20 m × 20 m. The measurements of habitat conditions (e.g., number of species, soil moisture, light intensity at ground level, height of plant cover) were carried out in 2018. The observations of the abundance and developmental structure of stems, as well as selected traits (e.g., height, number and dimensions of leaves, number of flowers) were conducted in 2018–2023. The analysis of phytosociological relevés showed that the study sites in Wolski Forest and Mount Chełm were located in the Tilio cordatae–Carpinetum betuli oak-hornbeam forest association, while the study site in Hrabeński Forest was situated in the Dentario glandulosae–Fagetum mountain beech forest association. The statistical analysis confirmed that the greatest Shannon and Simpson index values, number of species, soil humidity, light intensity at ground level, and height of plant cover were recorded in Hrabeński forest. The greatest number of Lilium martagon stems and a lack of juvenile stems was found in population 3, while in less abundant populations—1 and 2—juvenile, immature, virginile, and generative stems were found. The statistical analysis showed that the highest immature and virginile stems with the greatest number of whorl leaves, as well as the substantial height of generative stems and number of whorl leaves observed in population 3, might be the result of growing in conditions of lateral shading provided by adjacent plants. The lowest height of immature and virginile stems recorded in population 1 and generative stems noticed in population 2 might be caused by them being overshaded by the canopy of surrounding trees. Moreover, the obtained results suggest the favourable impact of weather conditions during the meteorological spring and summer of 2019 on the growth of Lilium martagon stems. Nevertheless, the lack of a unified trend in the studied populations indicates the occurrence of site-specific temporal variability of individual traits. Considering the obtained results, it can be concluded that population 3 presents a much better state and prospects for persistence in the occupied site than populations 1 and 2. At the same time, it should be pointed out that further long-term observations of populations of Lilium martagon located in different habitat conditions are still strongly desired. Full article

Pine wood nematode (PWN, Bursaphelenchus xylophilus) is fatal to the pine trees around the world. Its northward and westward expansion in China endangers Larix spp., yet its molecular response remains understudied. We conducted transcriptomic analysis (RNA-seq) on three economically important larch species (Larix principis-rupprechtii, L. olgensis, and L. kaempferi) infected by geographically distinct PWN isolates (northern Fushun and southern Changde strains) at 1 and 3 days post-inoculation. Comparative RNA-seq analysis of 36 samples revealed that genes such as oxidative stress, and secondary metabolite production were differentially expressed in Larix spp. upon infection by the PWNs. Furthermore, compared to the Changde strain, infection with the Fushun PWN strain can elicit a consistently stronger and more distinct transcriptional defense response across all tested larch species. These results provide insights into the molecular mechanisms of plant defense against PWNs, offering genetic target for resistance breeding and informing the development of targeted control measures against this pathogen. Full article

The lemur tree frog (Agalychnis lemur), a critically endangered species, can benefit from ex situ conservation programs; however, managing amphibians under human care presents challenges, including the provision of appropriate nutrition. House crickets (Acheta domesticus), a common feeder insect, have an inverse calcium to phosphorus ratio (Ca:P; 0.15:1) and low calcium content (<0.3%). While gut-loading crickets with an 8% calcium diet can improve their calcium concentrations, no study has assessed the effects of dietary calcium on bone development in Agalychnis spp. Moreover, no study has examined how diet impacts the gut–skin axis and skin microbiome of these frogs. This study examined how crickets gut-loaded with either a 1.3% or 8% calcium diet affected lemur tree frog bone density and skin microbiome. We hypothesized that frogs consuming the 8% calcium diet would exhibit significantly higher Hounsfield units (HU; bone density) over time, as measured by micro-computed tomography (mCT), and that dietary calcium concentration would have no effect on skin bacterial and fungi microbiomes. Eleven juvenile lemur tree frogs underwent mCT scans at baseline and 90 and 180 days. Total body volume of interest analysis showed a significant increase in HU in the 8% calcium group compared to the 1.3% group (F = 9.9, p = 0.01). There was no significant difference noted in the alpha or beta diversities for the bacterial and fungal microbiomes between dietary groups. This study provides the first evidence of dietary calcium’s impact on bone density in lemur tree frogs, offering valuable insights for improving ex situ management of this species. Full article

The conservation and genetic improvement of rare and endangered tree species are crucial for sustainable forest management. Liriodendron chinense, a relict species with limited distribution in China, exhibits high cross-compatibility with Liriodendron tulipifera, providing opportunities for interspecific hybrid breeding. In this study, 29 Liriodendron hybrids were established in a progeny trial plantation in Fujian Province, China, and subjected to multi-year evaluation of tree height, diameter at breast height (DBH), and individual stem volume. Significant differences (p < 0.01) among hybrids and hybrid × replicate interactions were detected for all traits across all assessment years, with individual stem volume showing the highest phenotypic coefficient of variation (35.30–40.56%). The mean annual increment in tree height increased during the early years, peaking at 1.50 m in the fourth year. Broad-sense and narrow-sense heritabilities for growth traits were consistently high (0.4073–0.7253 and 0.3410–0.6501, respectively), and the ratio of narrow-sense to broad-sense heritability ranged from 0.64 to 0.99, supporting the feasibility of early hybrid and individual selection. At a 10% selection intensity, hybrids No. 39, No. 59, and No. 74 were identified as elite, with selection based on individual stem volume providing the highest predictive accuracy and genetic gain (26.54–34.69%). Individual selection at a 1% intensity yielded genetic gains of 95.55–107.12% for stem volume. These results demonstrate substantial potential for early and efficient genetic improvement in Liriodendron hybrids, providing a theoretical foundation for the selection and deployment of elite hybrids and individuals in subtropical forest plantations. Full article

The eastern Baltic region is rich in hemiboreal forests, which are both commercially important and provide habitats for rare and/or endangered forest-dwelling species, which are sensitive to accelerating climatic changes. Under the intensifying climatic disturbances that are stressing forests worldwide, sanitary logging is a widely used harvesting technique for the mitigation of commercial losses. The effects of salvage logging on the biodiversity of forests remain ambiguous due to the larger scale and higher intensity of timber harvesting, which can alter the recovery of stands and succession of their vegetation. Furthermore, EU legislation is increasingly emphasizing conservation/restoration and mandating its implementation. The recovery of ecosystems, and hence the biodiversity of disturbed managed forests, can take several decades to centuries, depending on the site conditions. Long-term (~60 years, four remeasurements) changes in the composition and structure of vegetation, as an indicator of overall health and nutrient cycling, were studied in conventionally managed hemiboreal forests. Potential forest transformation (paludification) risks associated with large-scale logging were assessed in mixed coniferous stands in the Baltics, Latvia. Following logging, the stands were conventionally managed, including artificial regeneration. According to ground cover vegetation, 50 years was the period for the disturbance effects to start subsiding, as a dynamic equilibrium was reached and the canopies of regenerating trees were closing. A gradual decrease in moisture levels in the middle parts of salvage-logged areas, and later at their edges, indicated that the stands have escaped paludification, likely as the climate has been warming. Distance from the edge of the salvage-logged areas had a secondary effect on ground cover vegetation recovery after storms, alleviating concerns about the explicit negative impact of the scale of harvesting. Thus, in managed seminatural forest landscapes with a historically small to moderate scale of anthropogenic disturbance, salvage logging at a scale locally deemed as large had a transient effect in the Baltics. This indicates successful regeneration of the forest ecosystem over a timeframe shorter than the conventional rotation period, suggesting overall conservation efficiency of conventionally managed forests. Accordingly, salvage logging can be sustainable in terms of biodiversity and forest continuity in the long run under traditional management, as environmental changes accelerate. Full article

Gyrovirus galga 1 (GyG1) can infect a variety of animals and humans, but prevention and control strategies are limited, which endangers the healthy development of the poultry breeding industry and has a potential impact on public health safety. The live poultry market (LPM) connects the production and consumption ends, and the pathogen may spread across regions through transportation and personnel flow. To understand the prevalence of GyG1 in Guangxi, 3482 samples from LPMs, namely, 2693 chicken throat and cloacal swabs and 789 environmental samples collected in Guangxi from December 2019 to December 2024, were assayed by PCR. The results revealed that GyG1 was present in chicken and environmental samples from LPMs in Guangxi, China, with positivity rates of 17.08% and 13.31%, respectively. Eight GyG1-positive samples were randomly selected, including 5 chicken swab samples and 3 environmental samples for whole-genome amplification. The amino acids encoded by the three ORFs were analysed, and some mutation sites unique to these 8 variants were found. The homology between the 8 GyG1 genomes and 36 reference sequences was 96.8–99.8%. The homology of the VP1 gene sequence was 96.5–99.9%, and the homology of the amino acid sequence was 99.4–100%. A phylogenetic tree was constructed on the basis of the 8 GyG1 genomes and 36 GyG1 reference genome sequences from 14 different species (8 from zoos) in this study. The 44 sequences were divided into three branches constituting groups A, B and C, with the 8 novel strains classified into group A2. Recombination analysis predicted that two recombination events in the GyG1 sequence were associated with the emergence of Guangxi strain GX-AGV2-202109-5. This study clarified the prevalence and molecular characteristics of GyG1 in LPMs in Guangxi, China, were clarified for the first time, providing important data supporting the prevention and control of GyG1 infection and providing a reference for further understanding the epidemiology and genetic diversity of GyG1. Full article

Global warming has become one of the most serious threats to biodiversity. However, the responses of endangered tree species in subtropical regions to climate change and their potential distribution shifts remain elusive. In this study, we selected nine rare and endangered tree species in the subtropical forests of China encompassing both coniferous and broad-leaved groups, and conducted an assessment of their suitable distribution patterns and spatial shifts under current and future climate scenarios (SSP126, SSP370, and SSP585). For this we utilized an optimized MaxEnt model integrating multidimensional environmental variables including climate, soil, and topography. The results show that the model has high predictive accuracy after parameter optimization, with mean AUC values exceeding 0.98 for both broad-leaved and coniferous tree species. Our analysis of environmental factors indicates clear differences in distribution-limiting factors between the two functional groups. Broad-leaved species are primarily constrained by temperature-related variables, particularly the mean temperature of the coldest quarter (Bio11) and the mean diurnal range (Bio2), whereas coniferous species are more sensitive to moisture conditions, with the precipitation of the driest quarter (Bio17) as the key limiting factor for their potential distributions. Under current climatic conditions, highly suitable habitats for both functional groups are mainly concentrated in the middle and lower reaches of the Yangtze River. Under future climate scenarios, broad-leaved species are in general expected to expand in marginal areas, while coniferous species show pronounced scenario dependence, with significant contractions occurring under certain scenarios and time periods. Despite the evident changes at distribution margins, the overall shifts in the centroids of potential distributions for both functional groups will be limited, with core suitable areas remaining relatively stable. This study reveals differences in the spatial response patterns between conifers and broad-leaved trees, and provides a scientific basis for the development of differentiated conservation strategies and the identification of conservation priority areas under climate change. Full article

In this paper, the effects of Poland’s forest management evolution after 1945 on forest biodiversity at the genetic level were analysed. Forest biodiversity changes across the two politically and economically different eras (socialism, 1945–1989, and democracy, from 1990) are interpreted using three indirect indicators: forest regeneration and expansion, tree genetic resources, and threatened forest species. In the era of socialism, the total area of regeneration and reforestation gradually decreased, with these activities relying almost exclusively on cultivated reproductive material. After 1990, there was a relative stabilisation in the total area, with a noticeable increase in the use of natural processes to diversify the tree gene pool. Work on verifying and protecting the forest tree seed base, as well as on assessing the conservation status of an increasingly wide range of organisms, began in the era of socialism; however, it was intensified only in the era of democracy. In the latter case, the increase in the number of endangered species suggests a potentially negative trend. However, the actual assessment of the changes is not entirely clear due to subsequent changes in threat classification and increased knowledge of the occurrence of individual species. Dilemmas and problems related to the following issues require further discussion and resolution or implementation of further measures: the consequences of past choices regarding planted trees; the use of natural regeneration; the reduction in the forest tree gene pool as a result of artificial selection; incomplete knowledge about threats to the forest gene pool; the continued impact of threats and the possibilities for counteracting them; and securing funding for measures to protect biodiversity at the genetic level. Full article

Climate change is altering temperature and precipitation regimes in Argentina, with potential consequences for regeneration and persistence of forest tree species, emphasizing the importance of ex situ seed conservation. We evaluated interannual variation in seed traits, desiccation tolerance, storage behavior, and longevity of Cedrela balansae C. DC. and C. fissilis Vell. (Meliaceae), two endangered native species of subtropical rainforests in Argentina. Both species produced desiccation-tolerant seeds, independently of collection year, seed traits, or climatic conditions. Depending on the species, seed traits and longevity varied across years and showed strong relationships with temperature and precipitation, particularly during seed development. Cedrela balansae seeds are medium-lived seeds and have high longevity under standard seed banking conditions, suggesting strong potential for long-term ex situ conservation. Cedrela fissilis seeds are short-lived seeds and have high sensitivity to the storage environment. Correlations among climatic variables and seed traits and longevity parameters suggest that future warming and drying environments may shorten the window for germination and seedling establishment, with species-specific responses depending on climatic conditions during seed development. These results highlight the importance of climate effects in determining seed traits and seed longevity and emphasize the role of seed banking as a critical conservation strategy under climate change. Full article

Endophytic fungi enhance plant growth and stress resilience, yet their molecular roles in the roots of the endangered tree Phoebe bournei remain unclear. A comparative RNA-seq analysis was performed on root transcriptomes from wild, endophyte-colonized adult trees (OT) and axenically grown seedlings (ST). Unmapped reads were analyzed against the NCBI nucleotide (NT) database using BLASTN (v2.17.0), revealing Rhizophagus irregularis as the predominant endophytic fungus. Differential expression analysis identified 5891 DEGs, which were significantly enriched in pathways related to plant–pathogen interactions, phenylpropanoid biosynthesis, plant hormone signal transduction, and MAPK signaling. Key upregulated genes included PbMPK3, PbCML42, PbCML41.2, and PbGSTU28, suggesting enhanced ROS scavenging, calcium signaling, and defense activation. RT-qPCR validation confirmed the transcriptomic trends for selected genes. Our findings reveal that root endophytic fungi modulate a coordinated network involving immune priming, phytohormone regulation, and redox homeostasis, thereby supporting root development and enhancing resistance to biotic and abiotic stresses in P. bournei. This study provides foundational molecular insights into beneficial plant–endophyte interactions and identifies candidate genes that are valuable for the conservation and breeding of this threatened species. Full article

Coptis chinensis var. brevisepala W. T. Wang & P. G. Xiao is an endemic and endangered medicinal plant in China whose wild populations are rapidly declining under the combined pressures of overharvesting, climate change, and habitat fragmentation. Using genotyping-by-sequencing, we analyzed 87 individuals from 15 populations in Zhejiang Province, China, and identified 155,611 high-quality SNPs. The species exhibited low genetic diversity and strong genetic differentiation among populations with restricted gene flow (population-averaged H_o = 0.066, H_e = 0.067, π = 0.078, F_IS = 0.029, F_ST = 0.503, Nm = 0.329, gRelMig = 0.136). Analysis of molecular variance showed that variation among populations accounted for 73.58% of the total genetic variation (p < 0.001). A phylogenetic tree, principal component analysis (PCA), and admixture analysis consistently resolved the 15 populations into two major groups, which could be further subdivided into four subgroups. Mantel and partial Mantel tests indicated that geographic isolation is the primary driver of genetic differentiation, while environmental factors such as ultraviolet radiation and low temperature may contribute to fine-scale divergence at local spatial scales. Furthermore, MMRR analysis provided further confirmation of the independent and dominant role of geographic isolation. This study provides key data on the genetic diversity and population structure of C. chinensis var. brevisepala and offers a genetic basis for developing regionally differentiated conservation strategies and promoting its sustainable utilization. Full article

Population size estimates are essential for investigating numerous aspects of the ecology, evolution, and conservation of wildlife. However, the life cycles of many species include cryptic life stages that are difficult to detect or sample, such as the non-breeding fractions typical of many bird populations. Quantifying the proportions of breeders and non-breeders is crucial to better assess their conservation status and population trends. We propose a simple method applicable to species that show phenotypic differences between adults and juveniles. By quantifying the proportion of ages, the size of the whole population, and its productivity, the size of the non-breeding and breeding fractions can be inferred. We applied this approach to the red-spectacled amazon, Amazona pretrei, a threatened parrot endemic to the Brazilian Atlantic Forest. The entire global population aggregates in winter in a few localities to feed on the seeds of the Parana pine Araucaria angustifolia, a critically endangered tree whose range has declined >97% due to massive exploitation. From a global population of ~16,000 individuals in 2015 and ~20,000 individuals in 2017, our methodology allowed us to estimate a low proportion of juveniles (14%) and a large proportion of non-breeders (80%) within the adult population, with narrow confidence intervals. These proportions did not change between years, but the estimated number of breeding pairs increased, from ca. 1300 to 1700 pairs, in parallel with the global population increase. Our methodology, with its possible improvements to reduce uncertainty in estimates, can be applied to the long-term monitoring of this and many other species, to better understand their conservation challenges and inform effective management strategies. Full article

Hermit beetles (Osmoderma spp.) are protected and endangered across Europe, experiencing ongoing decline throughout most of their range. Because nearly all populations are small and isolated, Osmoderma genus is highly susceptible to extinction and requires active conservation measures. The primary cause of decline in the genus is habitat loss, particularly the removal of hollow trees that provide essential larval habitat. The nutritional wood mold within these hollows, on which larvae depend for 3–4 years of development, is directly linked to population survival. The aim of this study was to develop methodical ex situ breeding guidelines for reintroduction designed to eliminate environmental constraints and ecological requirement gaps. We first synthesize literature-based evidence on habitat conditions, applied methods, study durations, and key ecological insights relevant to Osmoderma conservation. Based on these results, we then create an ex situ breeding guideline for reintroduction, combining published data with practical breeding objectives in cases where empirical data are limited. Full article