Wildlife Conservation Management Research Articles

Uncovering habitat associations and thresholds—insights for managing breeding waterfowl in Eastern Canada

ContextUnderstanding how habitat influences species abundance is crucial in developing ecologically sound wildlife conservation management plans. Exploring habitat associations and ecological thresholds in species’ responses allows for better conservation and management on a landscape-scale.ObjectivesThis work aimed to identify habitat drivers and response thresholds of waterfowl and waterbird species’ densities in eastern Canada to support key landscape-level decisions for habitat conservation and wetland management.MethodsWe developed predictive abundance models for 17 species across eastern Canada from 2001 to 2015 using data from four regional surveys and identified areas where prioritizing enhancement of wetlands would increase the breeding density of five priority waterfowl species.ResultsHabitat associations and spatial abundance patterns varied across species, but most species responded strongly to forest composition, agriculture, and wetland features. Threshold effects occurred and varied among species, yet generally once 14% of a plot was covered in wetlands, positive effects of increased wetland diminished for most species. Our results allow for the targeting of investments in increasing wetland area along portions of eastern Canada that provide the best opportunities to increase breeding densities for priority waterfowl species.ConclusionsUnderstanding species-habitat associations and response thresholds allows for landscape management and planning and prioritization of limited resources. We suggest that management and wetland enhancement efforts for waterfowl in eastern Canada should be guided by predictive models and response thresholds of key habitat attributes to best prioritize actions that will have the biggest positive impact on multiple species.

Impact of infectious diseases on wild bovidae populations in Thailand: insights from population modelling and disease dynamics.

The wildlife and livestock interface is vital for wildlife conservation and habitat management. Infectious diseases maintained by domestic species may impact threatened species such as Asian bovids, as they share natural resources and habitats. To predict the population impact of infectious diseases with different traits, we used stochastic mathematical models to simulate the population dynamics over 100 years for 100 times in a model gaur (Bos gaurus) population with and without disease. We simulated repeated introductions from a reservoir, such as domestic cattle. We selected six bovine infectious diseases; anthrax, bovine tuberculosis, haemorrhagic septicaemia, lumpy skin disease, foot and mouth disease and brucellosis, all of which have caused outbreaks in wildlife populations. From a starting population of 300, the disease-free population increased by an average of 228% over 100 years. Brucellosis with frequency-dependent transmission showed the highest average population declines (-97%), with population extinction occurring 16% of the time. Foot and mouth disease with frequency-dependent transmission showed the lowest impact, with an average population increase of 200%. Overall, acute infections with very high or low fatality had the lowest impact, whereas chronic infections produced the greatest population decline. These results may help disease management and surveillance strategies support wildlife conservation.

Anthropogenic, environmental and temporal associations with vertebrate road mortality in a wildland-urban interface of a biodiverse desert ecoregion.

Road mortality adversely affects wildlife populations. As urbanization and infrastructure densities expand, transportation and wildlife management aim to mitigate wildlife-vehicle conflicts while conserving biodiversity. Roadways in aridland ecosystems can invariably and adversely impact wildlife differently from temperate and other biomes, yet these rapidly urbanizing regions are understudied as are urban-rural gradients. We conducted road-cruise surveys (n = 204; 2018-2023) to assess anthropogenic, environmental, and temporal factors associated with vertebrate roadkill across the wildland-urban interface of Arizona's biodiverse Sonoran Desert ecoregion-already subjected to increased human development and climate change. Of n = 2019 vertebrates observed, 28.5% were roadkill. Increasing urbanization levels were associated with reduced vertebrate abundance on roads and increased road-killed endothermic vertebrates. Traffic volume was strongly associated with reduced vertebrate abundance and increased roadkill; additive effects on roadkill began at approximately 20 vehicles. Daily low temperature and/or relative humidity were also associated with roadkill across vertebrate groups. We provide empirical evidence to understand wildlife-roadkill associations across expanding wildland-urban interfaces to inform effective roadkill mitigation and wildlife conservation management strategies in biodiverse aridland regions. We recommend that managers mitigate or avoid development in rural areas that possess high biodiversity, valuable waterways or migration corridors, and populations of vulnerable species.

Climate change introduces threatened killer whale populations and conservation challenges to the Arctic.

The Arctic is the fastest-warming region on the planet, and the lengthening ice-free season is opening Arctic waters to sub-Arctic species such as the killer whale (Orcinus orca). As apex predators, killer whales can cause significant ecosystem-scale changes. Setting conservation priorities for killer whales and their Arctic prey species requires knowledge of their evolutionary history and demographic trajectory. Using whole-genome resequencing of 24 killer whales sampled in the northwest Atlantic, we first explored the population structure and demographic history of Arctic killer whales. To better understand the broader geographic relationship of these Arctic killer whales to other populations, we compared them to a globally sampled dataset. Finally, we assessed threats to Arctic killer whales due to anthropogenic harvest by reviewing the peer-reviewed and gray literature. We found that there are two highly genetically distinct, non-interbreeding populations of killer whales using the eastern Canadian Arctic. These populations appear to be as genetically different from each other as are ecotypes described elsewhere in the killer whale range; however, our data cannot speak to ecological differences between these populations. One population is newly identified as globally genetically distinct, and the second is genetically similar to individuals sampled from Greenland. The effective sizes of both populations recently declined, and both appear vulnerable to inbreeding and reduced adaptive potential. Our survey of human-caused mortalities suggests that harvest poses an ongoing threat to both populations. The dynamic Arctic environment complicates conservation and management efforts, with killer whales adding top-down pressure on Arctic food webs crucial to northern communities' social and economic well-being. While killer whales represent a conservation priority, they also complicate decisions surrounding wildlife conservation and resource management in the Arctic amid the effects of climate change.

Empirical Analysis of Factors Influencing Elephant Population Increases: A Case Study of Tanzania National Park

This study employs empirical analysis through linear regression to investigate the determinants of elephant population increases (EP). Utilizing a dataset comprising 255 observations, the research evaluates the impact of various predictor variables such as Elephant crime decrease (ECD), Elephant death decrease (EDD), Elephant poaching decrease (EPD), Elephant conflict increase (ECI), Elephant tracking improved (ETI), Patrol coverage increase (PCI), GIS coordination (GC), and Communication improves (CI) on Elephant population dynamics. The regression model's overall significance (F (8, 246) = 41.4, Prob > F = 0) indicates a robust explanation of variance in EP by the combined effect of predictors. Notably, Elephant death decrease, increased patrol coverage, and improved communication emerge as statistically significant predictors of EP. The findings underscore the importance of targeted interventions in reducing elephant mortality, enhancing patrolling efforts, and strengthening communication strategies for wildlife conservation management. This research contributes to the understanding of factors influencing elephant population dynamics, thereby assisting stakeholders such as wildlife conservation agencies, government bodies, and researchers in informed decision-making.

Applications of DNA Barcoding in Fisheries: A Review

The review article focuses on the widespread application of DNA barcoding in the fishery background. With the advancement in science and technology, there is a dire necessity for upgradation in approaches for taxonomy, wildlife conservation, and health management in the fishery industry. To reduce invasiveness, illegal fishing, and health complications in fish in both marine as well aquaculture ecosystems different required mitigative measures need to be enforced. DNA barcoding is one important tool in biological science. It involves the sequencing of a small DNA segment called a ‘barcode’ of 648 base pairs. In animals and protists, the specific barcode is the mitochondrial gene cytochrome oxidase Ⅰ (COⅠ or COX 1) and it has proven to be extremely effective in identifying metazoans such as birds, butterflies, fish, flies, and many other animal groups. The use of DNA Barcoding has been proven to be effective in taxonomical classification of every group of organisms. In fishery, the application of barcoding created an avenue in marine conservation and aquaculture caretaking.

Microplastics ingestion and endocrine disrupting chemicals (EDCs) by breeding seabirds in the east tropical Atlantic: Associations with trophic and foraging proxies (δ15N and δ13C)

In this study we found that endocrine disrupting chemicals (EDCs) were omnipresent in a tropical seabird community comprising diverse ecological guilds and distinct foraging and trophic preferences. Because EDCs tend to bioaccumulate within the food web and microplastics can absorb and release harmful chemical compounds, our findings draw attention to the potential threats to wildlife. Thus, the goal of this study was to investigate the role of plastic ingestion, trophic and foraging patterns (δ15N and δ13C) of five tropical seabird species breeding in sympatry, on the exposure to EDCs, namely Polybrominated diphenyl ethers (PBDEs), methoxylated polybrominated diphenyl ethers (MeO-PBDEs) and personal care products (PCPs, e.g., musk fragrances and UV-filters). Results indicated that microplastics occurrence and EDCs detection frequency varied among species. Microplastics occurrence was higher in species with dual and coastal foraging strategies. Preen oil had higher levels of MeO-PBDEs and PCPs, while serum had higher levels of PBDEs. In brown boobies, the correlation between microplastics and ∑PBDEs levels was significant, suggesting that microplastics ingestion is a key PBDEs route. Trophic position (δ15N) plays a key role in PBDEs accumulation, particularly in Bulwer's petrel, which occupies a high trophic position and had more specialized feeding ecology than the other species. MeO-PBDEs were linked to foraging habitat (δ13C), although the link to foraging locations deserves further investigation. Overall, our findings not only fill key gaps in our understanding of seabirds' exposure to microplastics and EDCs, but also provide an essential baseline for future research and monitoring efforts. These findings have broader implications for the marine wildlife conservation and pollution management in sensitive environments, such as the tropical regions off West Africa.

PandaGUT provides new insights into bacterial diversity, function, and resistome landscapes with implications for conservation

BackgroundThe gut microbiota play important roles in host adaptation and evolution, but are understudied in natural population of wild mammals. To address host adaptive evolution and improve conservation efforts of threatened mammals from a metagenomic perspective, we established a high-quality gut microbiome catalog of the giant panda (pandaGUT) to resolve the microbiome diversity, functional, and resistome landscapes using approximately 7 Tbp of long- and short-read sequencing data from 439 stool samples.ResultsThe pandaGUT catalog comprises 820 metagenome-assembled genomes, including 40 complete closed genomes, and 64.5% of which belong to species that have not been previously reported, greatly expanding the coverage of most prokaryotic lineages. The catalog contains 2.37 million unique genes, with 74.8% possessing complete open read frames, facilitating future mining of microbial functional potential. We identified three microbial enterotypes across wild and captive panda populations characterized by Clostridium, Pseudomonas, and Escherichia, respectively. We found that wild pandas exhibited host genetic-specific microbial structures and functions, suggesting host-gut microbiota phylosymbiosis, while the captive cohorts encoded more multi-drug resistance genes.ConclusionsOur study provides largely untapped resources for biochemical and biotechnological applications as well as potential intervention avenues via the rational manipulation of microbial diversity and reducing antibiotic usage for future conservation management of wildlife.6KUVWwvzFXHebBwiyZoAvnVideo

FOOD SUPPLEMENTATION INCREASES MULE DEER (Odocoileus hemionus eremicus) RETENTION AT THE RANCHO SAN HUBERTO WILDLIFE CONSERVATION MANAGEMENT UNIT, SONORA, MEXICO

Artificial food and water supplementation programs are common in Wildlife Conservation Management Units (UMAs) in arid northern Mexico to attract and retain mule deer as quality trophies. However, implementing these actions represents a high economic cost, and there is no convincing evidence of their effectiveness. This study evaluated the effect of food and water supplementation by capture-mark-recapture using camera traps at the UMA San Huberto, Sonora, Mexico. During the winter of 2015-2016, male mule deer counts and detection histories were collected at 62 photo-trapping stations spread across four supplementation treatments: 1) water and food, 2) water, 3) food, and 4) no supplementation. In addition, to assess the impact of natural vegetation on trough and feeder utilization on the ranch, the Normalized Difference Vegetation Index was calculated using Landsat 8 satellite images. A log-Poisson regression model for deer counts per photo-trapping station found that food supplementation increased mule deer numbers by 42 % when compared to stations without food supplementation. Vegetation biomass had no effect on the frequency of use of feeders and waterers in any of the treatments. According to the multistate model for detection histories, male mule deer at waterers receiving food-only supplementation are more likely to remain in that treatment than to move to either of the other two treatments (water and feed or water). This finding suggests that food-only supplementation is more effective in retaining male mule deer.

Conservation of skinks in New Zealand cities

Urbanisation dramatically alters ecosystems, disrupting key processes and threatening species persistence. Despite growing knowledge of the impacts of cities on wildlife, particularly for birds and mammals, there remains a paucity of research on how urbanisation impacts other taxa, including reptiles. We examined how urbanisation affects skink communities across multiple New Zealand cities by undertaking pitfall trapping surveys in a range of habitats. Of the 20 endemic species thought to have been present historically in the cities, only four were captured during surveys, Oligosoma aeneum in Hamilton; O. polychroma, O. aeneum, and O. ornatum in Wellington; O. polychroma in Nelson; and O. aff. polychroma Clade 5 in Dunedin. Our results reveal highly variable patterns of occupancy, abundance, and complex associations with key threats and habitat modifications. Sites in Nelson and Wellington were much more likely to record skinks than Hamilton and Dunedin, and modelling showed abundance of O. polychroma was positively related to rat tracking rates when grass cover was low but showed a negative relationship when grass cover was high. O. polychroma body condition was negatively associated with the proportion of urban land cover (built up areas or transport infrastructure). The low number of captures of several species is concerning and long-term monitoring is needed to assess the trajectories of these vulnerable populations. Effective conservation management of urban wildlife requires knowledge of where populations exist and how urban processes affect persistence. For understudied urban-dwelling taxa such as reptiles, the lack of this information may be putting populations at risk.

Landscape determinants of genetic structure for Schizopygopsis younghusbandi in the Yarlung Tsangpo River drainage, Tibetan Plateau

Unraveling the drivers that shape landscape genetics could help better understand the relationship between genetic structure and environmental factors and provide a scientific basis for wildlife conservation and habitat management. In this study, a typical coldwater fish on the Tibetan Plateau, Schizopygopsis younghusbandi, was selected to explore its spatial genetic structure and the determinant factors using mitochondrial cytochrome b gene as the molecular marker. The results showed a total of 80 haplotypes and 90 variable sites among 663 individuals from 25 geographical populations, with haplotype diversities (Hd) ranging from 0.636 to 0.936 and nucleotide diversities (Pi) ranging from 0.00160 to 0.00450. Significant positive correlations were observed between Hd and spatial factors (longitude and elevation) as well as the majority of single or combined bioclimatic factors. The correlations between Pi and these factors were inconclusive, revealing that Hd was more sensitive than Pi to population dynamic fluctuations. The phenomenon of greater genetic diversity in higher, colder and drier areas was consistent with the central-marginal hypothesis for this highland-origin species. The majority of genetic differentiation indices Fst indicated moderate differentiation, showing genetic heterogeneity among geographical populations. Fst was positively correlated with variations of elevation and the first principal component of bioclimatic factors, showing a weakly positive relationship with river-network distance, which demonstrated that the Isolation-by-Environment model could explain this genetic structure. In conclusion, as a highly specialized coldwater fish, S. younghusbandi retained higher genetic diversity in higher, colder and drier areas, and population differentiation was mostly related to differences of local bioclimate. For future conservation, we advocate that different geographical populations be treated as separate conservation units, with close attention paid to marginal populations, which are more vulnerable to external disturbances and exhibited less genetic variation.

Assessment of habitat suitability and connectivity across the potential distribution landscape of the sambar (Rusa unicolor) in Southwest China

Habitat suitability assessment is the basis for wildlife conservation management and habitat restoration. It is a useful tool to understand the quality of wildlife habitat and its potential spatial distribution. In order to reveal the habitat suitability and connectivity of sambar (Rusa unicolor) to promote species and biodiversity conservation, this study collected records of sambar (Rusa unicolor) from over 2,000 camera traps in the forests of Southwest China in the past 5 years to assess the overall situation of their habitat. The results of the species distribution model revealed that the suitable habitat area for sambar in the five major mountain ranges (Minshan, Qionglai, Daxiangling, Xiaoxiangling, and Liangshan) in Southwest China is 18,231 km2, accounting for 17.02% of the total area. The most suitable habitat of sambar is primarily distributed in Qionglai, as well as the intersection areas of Daxiangling, Xiaoxiangling, and Minshan. The temperature annual range, temperature seasonality, elevation, and distance to road were important factors affecting the distribution of suitable habitat for sambar. Analysis of landscape pattern shows that there were 273 habitat patches, with a maximum patch area of 9,983 km2, accounting for 54.8% of the total suitable habitat area. However, the segmentation index and separation index of each habitat patch were 0.99 and 106.58, respectively, indicating a relatively high habitat fragmentation in the study area. The results of habitat connectivity analysis showed that the Qionglai mountains have the largest suitable habitat area and the highest connectivity among habitat patches. However, habitat connectivity between the five mountains is very low, suggesting that gene flow among these mountain ranges is probably limited. We therefore recommend strengthening protection of sambar and their habitat, with special attention to the establishment of corridors between the different mountain populations.

Consumption of Diets Based on Native Forages, Pumpkin and Corn by Collared Peccary (Pecari tajacu)

Aims: The study was carried out to evaluate the effect of the consumption of corn-based diets mixed with Brosimum alicastrum or pumpkin (Cucurbita sp) forage, on live weight, in the number of erythrocytes, leukocytes and serum urea nitrogen, in collared peccaries (Pecari tajacu) in captivity.
 Study Design: A four-treatment longitudinal comparative experiment with a repeated measures design was applied.
 Place and Duration of Study: Xmatkuil Wildlife Conservation Management Unit, in Mérida, Yucatán, Mexico, for three months.
 Methodology: Nine adult female collared peccaries (Pecari tajacu) were subjected to voluntary consumption of the following diets: T1: Diet with 60% of corn and 40% dry B. alicastrum forage, T2: Diet with 40% corn and 60% dry B. alicastrum, T3: Diet with 60% corn and 40% fresh pumpkin on dry matter basis, T4: Diet with 40% corn and 60% fresh pumpkin, for 14 days for each treatment. The dry matter intake of each treatment, live weight, number of leukocytes, erythrocytes and serum urea nitrogen in each of the specimens were measured. Response variables in each treatment were compared with repeated measures ANOVA or Friedman's test if parametric analysis requirements were not met.
 Results: There was no significant difference between live weights in each treatment (P=05) but there was a significant difference in dry matter intake between treatments. There was no significant difference in erythrocyte levels between treatments. There was no difference in leukocyte levels between treatments (P=0.05), but there was a difference in the means of urea nitrogen between treatments.
 Conclusion: Pumpkin diets with corn show higher levels of dry matter intake, higher levels of urea Nitrogen and a greater number of erythrocytes than diets with corn and dry B: alicastrum, so it is suggested that diets with pumpkin and corn are more suitable than with corn and dry B. alicastrum.

Invasion of annual grasses following wildfire corresponds to maladaptive habitat selection by a sagebrush ecosystem indicator species

Numerous wildlife species within semi-arid shrubland ecosystems across western North America are experiencing substantial habitat loss and fragmentation. These changes in habitat are often attributed to a diverse suite of factors including prolonged and increasingly severe droughts, conifer expansion, anthropogenic development, domestic and feral livestock grazing, and invasion of exotic annual grasses, which promotes increased wildfire frequency and severity. Greater sage-grouse ( Centrocercus urophasianus ; hereafter, sage-grouse) are considered an indicator of sagebrush ecosystem health and have experienced widespread population decline associated with habitat loss and degradation, as well as changes in predator communities. Our objectives were to model and map sage-grouse habitat selection and survival during the important brood-rearing life stage in relation to landscape-scale environmental predictors. Furthermore, we sought to understand impacts of wildfire and annual grass invasion on brood habitat, as these accelerated disturbance regimes are a primary cause of habitat loss within the Great Basin region of the USA. We used a hierarchical Bayesian modeling framework to estimate resource selection functions and survival for early and late brood-rearing stages of sage-grouse in relation to a broad suite of habitat characteristics evaluated at multiple spatial scales within the Great Basin from 2009 to 2019. Sage-grouse selected for greater perennial grass cover, higher relative elevations, and areas closer to springs and wet meadows during both early and late brood-rearing. Terrain characteristics, including heat load and aspect, were important in survival models, as was variation in shrub height. We also found strong evidence for higher survival for both early and late broods within previously burned areas, but survival within burned areas decreased as annual grass cover (i.e. cheatgrass, Bromus tectorum ) increased. This interaction effect demonstrates how invasion of annual grasses into burned areas, which has become prevalent in Great Basin sagebrush ecosystems, can lead to maladaptive habitat selection by brood-rearing greater sage-grouse. Understanding these complex relationships aids wildlife conservation and habitat management as wildfire and annual grass cycles continue to accelerate across western ecosystems.

Seasonal abundance of waterfowl for hunting in the southern portion of the Malaga wetland, Durango, Mexico

Objective: To estimate the composition and winter abundance of waterfowl for hunting in a Wildlife Conservation Management Unit (UMA), within the Malaga wetlands complex, Durango, Mexico. Design/Methodology/Approach: In the winter of 2019, waterfowl for hunting were identified and quantified in an UMA of the Malaga wetlands complex, Durango, Mexico. The birds were counted with the point count methodology in five repetitions, in order to estimate their specific richness and abundance in each one. These variables were compared using the Kruskal-Wallis test (p < 0.05). Results: A total of 21,620 birds from 18 species were registered. The most frequent families were the Anatidae, Rallidae, and Gruidae. Anser albifrons, A. caerulescens, and Anas crecca were the most abundant species. This abundance increased according to the number of tests. Therefore, the highest proportion of birds was recorded in the last sampling (p < 0.05). Study Limitations/Implications: This study provides baseline demographic information for this group of birds that inhabits the Durango wetlands. However, long-term monitoring is necessary to determine the demographic dynamics of these species. Findings/Conclusions: The study site is diverse and important for the waterfowl for hunting that spend the winter in Durango, Mexico

Fire as a driver and mediator of predator-prey interactions.

ABSTRACTBoth fire and predators have strong influences on the population dynamics and behaviour of animals, and the effects of predators may either be strengthened or weakened by fire. However, knowledge of how fire drives or mediates predator–prey interactions is fragmented and has not been synthesised. Here, we review and synthesise knowledge of how fire influences predator and prey behaviour and interactions. We develop a conceptual model based on predator–prey theory and empirical examples to address four key questions: (i) how and why do predators respond to fire; (ii) how and why does prey vulnerability change post‐fire; (iii) what mechanisms do prey use to reduce predation risk post‐fire; and (iv) what are the outcomes of predator–fire interactions for prey populations? We then discuss these findings in the context of wildlife conservation and ecosystem management before outlining priorities for future research. Fire‐induced changes in vegetation structure, resource availability, and animal behaviour influence predator–prey encounter rates, the amount of time prey are vulnerable during an encounter, and the conditional probability of prey death given an encounter. How a predator responds to fire depends on fire characteristics (e.g. season, severity), their hunting behaviour (ambush or pursuit predator), movement behaviour, territoriality, and intra‐guild dynamics. Prey species that rely on habitat structure for avoiding predation often experience increased predation rates and lower survival in recently burnt areas. By contrast, some prey species benefit from the opening up of habitat after fire because it makes it easier to detect predators and to modify their behaviour appropriately. Reduced prey body condition after fire can increase predation risk either through impaired ability to escape predators, or increased need to forage in risky areas due to being energetically stressed. To reduce risk of predation in the post‐fire environment, prey may change their habitat use, increase sheltering behaviour, change their movement behaviour, or use camouflage through cryptic colouring and background matching. Field experiments and population viability modelling show instances where fire either amplifies or does not amplify the impacts of predators on prey populations, and vice versa. In some instances, intense and sustained post‐fire predation may lead to local extinctions of prey populations. Human disruption of fire regimes is impacting faunal communities, with consequences for predator and prey behaviour and population dynamics. Key areas for future research include: capturing data continuously before, during and after fires; teasing out the relative importance of changes in visibility and shelter availability in different contexts; documenting changes in acoustic and olfactory cues for both predators and prey; addressing taxonomic and geographic biases in the literature; and predicting and testing how changes in fire‐regime characteristics reshape predator–prey interactions. Understanding and managing the consequences for predator–prey communities will be critical for effective ecosystem management and species conservation in this era of global change.

Ground-based counting methods underestimate true numbers of a threatened colonial mammal: an evaluation using drone-based thermal surveys as a reference

Context Accurate and precise monitoring practises are key for effective wildlife conservation management; providing reliable estimates of spatiotemporal changes in species abundance on which sound decision-making can be based. Advancements in drone and satellite technology are providing new standards for survey accuracy and precision and have great potential for enhancing population monitoring of numerous difficult to survey species. Flying-foxes (Pteropus spp.) are large bats that roost in groups of a few hundred to many thousands in the canopies of trees, where they are difficult to census accurately and precisely by human observers. Globally, 35 of the 64 flying-fox species are listed as threatened under the IUCN Red List of Threatened Species, and reliable monitoring methods are needed for the effective management of this ecologically important group. Aims Recently, we showed that drone-acquired thermal imagery can be used to count flying-foxes in their roost with high accuracy and precision. In the present study, we aimed to assess the accuracy and precision of whole colony counts derived from ground-based counting methods against reference counts derived from drone-acquired thermal imagery. Methods We evaluated the relationship between ground-based counts by two groups of human observers to highly accurate and precise counts derived from drone-acquired thermal orthomosaics for 25 counts conducted across seven flying-fox roosts throughout the Greater Sydney region, Australia. Key results We found that ground-based counts by human observers were positively correlated with those obtained from concurrent drone-acquired thermal imagery. However, drone-acquired estimates of colony size were 2.05 and 1.92 times higher than ground-based counts by the experimenter and Australian government counters respectively. When compared against drone-acquired reference counts, the precision (coefficient of variation) of ground-based counts was 26.3% when conducted by a single counter and 55.1% when conducted by multiple counters. Conclusions Our research indicates that ground-based counting methods underestimate true population sizes by substantial margins and have limited precision. Drone-based monitoring provides highly accurate and precise population estimates, and thus is expected to yield more reliable information on flying-fox abundance and allow for trends to be established over shorter timescales. Implications Using ground counting methods alone, population trends can only be established with significance after protracted periods of monitoring. Incorporating the use of thermal drones into current monitoring practises would enhance the capacity to detect population trends earlier and more accurately, so that conservation management can more effectively respond.

基于动物适宜栖息地的北京市自然保护地保护成效评估

PDF HTML阅读 XML下载 导出引用 引用提醒 基于动物适宜栖息地的北京市自然保护地保护成效评估 DOI: 10.5846/stxb202109022475 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（31872240）；国家林业和草原局项目（2021080323-1）；北京绿色生态空间保护空缺分析项目（2021XJL02） Assess the conservation effectiveness of the natural protected areas in Beijing based on the suitable habitat of wild animals Author: Affiliation: Fund Project: The National Natural Science Foundation of China (General Program, Key Program, Major Research Plan) 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:栖息地是野生动物赖以生存的基础，明晰物种的适宜栖息地分布是切实加强野生动物保护、提高生物多样性保护成效的重要基础。北京市野生动植物资源丰富，也建立了一系列自然保护地以加强对野生动物的保护。当前亟需系统评估北京市现有自然保护地体系对野生动物适宜栖息地的保护成效，为未来北京市野生动物保护管理和自然保护地体系整合工作优化提供科学指导。研究选取了北京地区6个较为典型的野生动物为主要研究对象，包括黑鹳（Ciconia nigra）、褐马鸡（Crossoption mantchuricum）、大鸨（Otis tarda）、鸳鸯（Aix galericulata）、金雕（Aquila chrysaetos）和斑羚（Naemorhedus griseus），利用MaxEnt模型和ArcGIS的空间分析功能分析其适宜栖息地的分布；将自然保护地与适宜栖息地相叠加，识别其适宜栖息地的分布热点和保护空缺，进而评估了北京市现有自然保护地体系的保护成效。研究结果表明，6个研究物种在现有的自然保护地体系中均得到了不同程度的保护，其中褐马鸡的受保护率最高（92.82%），鸳鸯的受保护率最低（13.66%）。各类自然保护地的物种热点区覆盖率不同，风景名胜区类型覆盖率最高（14.74%）。6个物种适宜栖息地的热点区域总面积为280.01km2，保护空缺占热点区域总面积的49.45%，其中密云区、门头沟区和房山区的保护空缺面积最大。基于现有自然保护地体系对野生动物适宜栖息地的保护效率以及存在的空缺，建议因地制宜，采取扩大或合并现有自然保护地、增设新的自然保护地或营造微生境等方式来提升自然保护地的整体保护效率。研究结果可为北京市自然保护地的整合优化提供重要依据，为野生动物重要栖息地的识别与划定提供可行方案，并为加强野生动物的保护管理提供科学指导。 Abstract:Habitats are essential for the survival of wild animals, and clarifying the distribution of a species' suitable habitat can be helpful to strengthen wildlife conservation and to increase the conservation effectiveness for biodiversity. As the capital of China, Beijing holds abundant wild animals and the government has established different types of natural protected areas to provide the refuge for the wildlife. Nowadays, it is urgent to assess the effectiveness of these natural protected areas on the protection of habitats of the wild animals, which will provide scientific guidance to wildlife conservation management and integration of natural protected areas in Beijing. Based on the relative importance and the availability of the distribution data, we selected 6 typical wild animals in Beijing, i.e., Black stork (Ciconia nigra), Brown eared-pheasant (Crossoption mantchuricum), Great bustard (Otis tarda), Mandarin duck (Aix galericulata), Golden eagle (Aquila chrysaetos) and Chinese goral (Naemorhedus griseus), and collected the distribution data of these species through field investigations, open databases and literature. We then analyzed the suitable habitats using the MaxEnt model and spatial analysis function of ArcGIS. We also identified the hotspots and GAPs (GAP analysis) of these species' suitable habitats in Beijing. The results indicated that the natural protected areas covered various proportions of these animals' suitable habitats with a range from 13.66% (Mandarin duck) to 92.82% (Brown-eared pheasant). The total area of the suitable habitat hotspots was 280.01 km2, and mainly distributed in Miyun District, Yanqing District, Mentougou District and Fangshan District. However, the coverage of species hotspots differed among different natural protected areas, with it being highest in scenic spots (14.74%). The GAPs were responsible for 49.45% of the hotspots and mainly distributed in Miyun District, Mentougou District, Fangshan District, and the border of Miyun, Huairou and Yanqing. In particular, Miyun District, Mentougou District and Fangshan District held the largest areas of GAPs. Based on the distribution of the suitable habitats and the protection gaps, it is suggested to take suitable measures to improve the conservation effectiveness of the natural protected areas according to the local circumstances, and adopt different protection strategies for different protection objects, including expanding or merging some natural protected areas, establishing new natural protected areas, and creating micro-habitats. Our study provides feasible solutions for the identification and delineation of important wildlife habitats in Beijing, provides some scientific guidelines for the wildlife management and integration and optimization of the natural protected area system. 参考文献 相似文献 引证文献

Genotyping-in-Thousands by sequencing of archival fish scales reveals maintenance of genetic variation following a severe demographic contraction in kokanee salmon

Historical DNA analysis of archival samples has added new dimensions to population genetic studies, enabling spatiotemporal approaches for reconstructing population history and informing conservation management. Here we tested the efficacy of Genotyping-in-Thousands by sequencing (GT-seq) for collecting targeted single nucleotide polymorphism genotypic data from archival scale samples, and applied this approach to a study of kokanee salmon (Oncorhynchus nerka) in Kluane National Park and Reserve (KNPR; Yukon, Canada) that underwent a severe 12-year population decline followed by a rapid rebound. We genotyped archival scales sampled pre-crash and contemporary fin clips collected post-crash, revealing high coverage (> 90% average genotyping across all individuals) and low genotyping error (< 0.01% within-libraries, 0.60% among-libraries) despite the relatively poor quality of recovered DNA. We observed slight decreases in expected heterozygosity, allelic diversity, and effective population size post-crash, but none were significant, suggesting genetic diversity was retained despite the severe demographic contraction. Genotypic data also revealed the genetic distinctiveness of a now extirpated population just outside of KNPR, revealing biodiversity loss at the northern edge of the species distribution. More broadly, we demonstrated GT-seq as a valuable tool for collecting genome-wide data from archival samples to address basic questions in ecology and evolution, and inform applied research in wildlife conservation and fisheries management.

Predicting koala (Phascolarctos cinereus) distribution from incidental sighting data in South-East Queensland, Australia

Species distribution maps are important tools for wildlife conservation planning and management. To model koala distributions, usually, a spatially representative sample of koala populations is collected through systematic field surveys. Details of koala sightings collected by members of the public could potentially be used to develop species distribution models if appropriate analytical approaches are applied to address the inherent biases in such datasets. We developed a stepwise approach for applying bias correction techniques to estimate and map koala distributions. Using a Boosted regression tree approach, we modelled indirectly the search effort made by observers to identify or sight koalas. Land lot density (58%) and human population density (19%) had the strongest positive impact on the indirect search effort, while the distances to roads were negatively associated with the indirect search effort. To estimate the koala distribution across South-East Queensland, we then developed models describing koala habitat (environmental model), access to koala habitat (accessibility model) and the search effort (search effort model), with the latter including the indirect search effort covariate. Finally, we corrected the estimates derived from these models (bias-corrected search effort and accessibility model). Three independent statistical modelling approaches (Lasso penalty Poisson regression, Down-weighted Poisson regression, and Maximum entropy) were used to compare the five koala distribution models. Based on assessments of areas under curves, the predictive accuracy of models improved when area accessibility and search effort were included. Overall, the spatial extent of koala distributions increased in the prediction maps when models were corrected for accessibility and indirect search effort (except for Down-weighted Poisson regression).