Human Disturbance Research Articles

Genetic connectivity of wolverines in western North America.

Wolverine distribution contracted along the southern periphery of its range in North America during the 19th and 20th centuries due primarily to human influences. This history, along with low densities, sensitivity to climate change, and concerns about connectivity among fragmented habitats spurred the recent US federal listing of threatened status and special concern status in Canada. To help inform large scale landscape connectivity, we collected 882 genetic samples genotyped at 19 microsatellite loci. We employed multiple statistical models to assess the landscape factors (terrain complexity, human disturbance, forest configuration, and climate) associated with wolverine genetic connectivity across 2.2million km2of southwestern Canada and the northwestern contiguous United States. Genetic similarity (positive spatial autocorrelation) of wolverines was detected up to 555km and a high-to-low gradient of genetic diversity occurred from north-to-south. Landscape genetics analyses confirmed that wolverine genetic connectivity has been negatively influenced by human disturbance at broad scales and positively influenced by forest cover and snow persistence at fine- and broad-scales, respectively. This information applied across large landscapes can be used to guide management actions with the goal of maintaining or restoring population connectivity.

Location Matters: Variations in Cloacal Microbiota Composition of Spatially Separated Freshwater Turtles.

The gut microbiota of vertebrates is malleable and may be shaped by both intrinsic and extrinsic factors. Here, the effect that geography has on the cloacal microbiota of two species of Australian freshwater chelonians, eastern longneck turtle (Chelodina longicollis) and Macquarie River turtle (Emydura macquarii), captured from waterbodies with different levels of anthropogenic pressure was investigated. We analysed the microbiota composition, structure and diversity through 16S rRNA gene amplicon sequencing. It was hypothesised that animals from less disturbed environments would harbour a more diverse cloacal microbial population. The cloacal microbiotas from 93 turtles (C. longicollis n = 78; E. macquarii n = 15), from five locations, were analysed. For both species, the most predominant phylum was Proteobacteria. Cloacal microbiota alpha diversity varied significantly between the C. longicollis from all locations, but no differences were found for E. macquarii. In C. longicollis, turtles from wetlands within the centre of Melbourne had the lowest alpha diversity metrics, while the highest alpha diversity values were seen in turtles captured from an undisturbed rural waterbody. Beta diversity, obtained by weighted UniFrac distance, showed significant differences between locations of capture for both species of turtles in this investigation. For C. longicollis, 87 biomarkers were identified responsible for explaining differences between locations, and in E. macquarii, 42 biomarkers were found. This is the first study to explore the cloacal microbiota composition of the eastern longneck turtle and gives greater insight into microbial community structures in Macquarie River turtles. Our study demonstrated that cloacal microbiota composition of freshwater turtles was significantly influenced by locality and that disrupted environments may reduce microbial diversity in C. longicollis. Interestingly, we discovered that the effects of location contrasted significantly between species for alpha diversity with differences discovered for C. longicollis but not E. macquarii. However, for both species, beta diversity was notably influenced by habitat type. These results highlight the need to interpret chelonian microbiota data in the context of geography and human disturbance of the environment.

Evaluating the influence of human disturbance on the ecosystem service scarcity value: an insightful exploration in Guangxi region

Investigating how human disturbance affects the ecosystem service scarcity value (ESSV) is crucial for maintaining ecosystem stability and achieving sustainable development goals (SDGs). This study separately assessed ESSV and human disturbance in Guangxi from 1990 to 2020, revealing their spatiotemporal distribution differences over time. The environmental Kuznets curve (EKC) is used to analyze the interrelationship between the two, with the purpose of filling the gap in current research. The main results are as follows: (1) From 1990 to 2020, ESSV in Guangxi increased significantly and reached its highest value in 2020. Under the four scenarios, ESSV increased significantly in Scenarios 2 and 4. Spatially, high ESSV was mainly distributed in some cities in central, southern, western and northeastern Guangxi. (2) The index of human disturbance in Guangxi continued to increase during the study period, with a high level of human disturbance in the central urban area and a low level of human disturbance in the peripheral areas, which were distributed in a radial pattern. (3) According to the EKC, the relationship between ESSV and human disturbance in Guangxi followed an inverted N-shaped curve. In addition, after 2010, the coupling and coordination level was dominated by “slightly balanced development”, and the area of “ESSV significantly lagged” gradually increased. This study provides a new perspective for understanding ESSV and its relationship with human disturbances, and provides an important reference for the sustainable management of ecosystems and the formulation of ecological conservation policies.

Vegetation changes of Lushan, China between 1959 and 2020 based on pollen data

Both climatic change and human activity are currently driving the dynamic of vegetation, which may vary from region to region. On Lushan, located in the eastern China, the subtropical secondary forests during the natural succession endure the pressure from ongoing climate warming on the one hand. They are influenced by anthropogenic disturbance on the other hand for recent decades. Previously, palynological research has discovered that the pollen assemblages from surface soil sample on Lushan can basically reflect the characteristics of local vegetation. Here, we did a comparative study by using the pollen analysis to investigate the vegetation changes of Lushan from 1959 to 2020. We compared the composition of pollen assemblages obtained in 1959 with that in 2020 along different altitudes. Further, the biomisation method was employed to discover the changes of different vegetation types, which were reflected by the pollen-based reconstructed biomes. Meanwhile, the temporal beta diversity analysis was used to extract the sites experienced the significant vegetation shift and the most important taxa change. Results showed that the pollen composition over the past 60 years on Lushan had altered remarkably. The vegetation shifted at all altitudes. The current vegetation pattern of Lushan: evergreen broadleaved forest in low elevation, temperate deciduous broadleaved forest in middle elevation and cool mixed forest in high elevation, is the successional consequence of the past 60 years. The forces driving the vegetation dynamics might be from multiple sources. However, the human disturbance seems to play quite an important role during forest succession. Our study is potentially useful both for paleoecological reconstructions and wider understanding of current climate change that are relevant to subtropical forests of Asia.

From nature to urbanity: exploring phyllosphere microbiome and functional gene responses to the Anthropocene.

The Anthropocene exerts various pressures and influences on the stability and function of the Earth's ecosystems. However, our understanding of how the microbiome responds in form and function to these disturbances is still limited, particularly when considering the phyllosphere, which represents one of the largest microbial reservoirs in the terrestrial ecosystem. In this study, we comprehensively characterized tree phyllosphere bacteria and associated nutrient-cycling genes in natural, rural, suburban, and urban habitats in China. Results revealed that phyllosphere bacterial community diversity, richness, stability, and composition heterogeneity were greatest at the most disturbed sites. Stochastic processes primarily governed the assembly of phyllosphere bacterial communities, although the role of deterministic processes (environmental selection) in shaping these communities gradually increased as we moved from rural to urban sites. Our findings also suggest that human disturbance is associated with the reduced influence of drift as increasingly layered environmental filters deterministically constrain phyllosphere bacterial communities. The intensification of human activity was mirrored in changes in functional gene expression within the phyllosphere microbiome, resulting in enhanced gene abundance, diversity, and compositional variation in highly human-driven disturbed environments. Furthermore, we found that while the relative proportion of core microbial taxa decreased in disturbed habitats, a core set of microbial taxa shaped the distributional characteristics of both microbiomes and functional genes at all levels of disturbance. In sum, this study offers valuable insights into how anthropogenic disturbance may influence phyllosphere microbial dynamics and improves our understanding of the intricate relationship between environmental stressors, microbial communities, and plant function within the Anthropocene.

Spatiotemporal Variations and Driving Factors of Ecological Sensitivity in the West Qinling Mountains, China, Under the Optimal Scale

This study selected the five indicators of soil erosion, climate environment, geological hazards, biodiversity, and human disturbances and uses the entropy weight method to calculate the ecological sensitivity of the West Qinling Mountains from 2000 to 2020. The analysis produced a spatiotemporal distribution of ecological sensitivity over the 20-year period. An equal step size of 500 m was used to progressively increase the spatial scale from 500 m to 6 km. The optimal scale for the spatial differentiation of ecological sensitivity in the West Qinling Mountains was determined by analyzing the characteristics of changes at different scales, response mechanisms, and optimal parameters for geographical detector spatial scale identification. Based on this scale, the change in intensity and pattern and the influencing factors of ecological sensitivity were analyzed. The results show the following: (1) The 5.5 km spatial scale balances the requirements of accuracy, spatial heterogeneity, and data adequacy, making it the optimal scale for analyzing the spatiotemporal variation patterns of ecological sensitivity in the West Qinling Mountains. (2) From 2000 to 2020, the mean ecological sensitivity in the West Qinling Mountains exhibited a decreasing trend, indicating an improvement in the ecological environment. Spatially, the ecological sensitivity of the West Qinling Mountains showed a spatial distribution pattern of “low in the west and high in the east, low in the south and high in the north”. During the study period, the ecological sensitivity in the West Qinling region remained generally stable, with no high-frequency changes observed. (3) Population density is the primary driving factor of spatial differentiation of ecological sensitivity in the West Qinling Mountains, while GDP serves as a secondary factor. Overall, socioeconomic factors have the most significant impact on ecological sensitivity. (4) Over 75% of the ecological sensitivity trends exhibit patterns of perennial unchanged and fluctuating unchanged trends, with areas of fluctuating increase smaller than areas of fluctuating decrease. Regions of perennial high sensitivity are primarily concentrated in the northeastern part of the West Qinling Mountains, while areas with increased fluctuation in ecological sensitivity are mainly located in the western and southern parts of the West Qinling Mountains. Future efforts should focus on these regions.

A Renaissance of Atoll Ecology

The approximately 320 atolls of the world, scattered across the tropical oceanic basins, constitute a unique type of ecosystem in that they are each an integrated unit consisting of island, coral reef, and lagoon components. Atolls have a complex geology, ecology, and biogeography, which can be fully appreciated only by transcending the classic boundary thinking of marine and terrestrial realms. The atolls we observe today were shaped by Quaternary sea-level fluctuations, which imposed strong environmental filters on their communities. As entirely biogenic, reef-borne structures, the islands of atolls depend upon marine productivity, which catalyzes island community assembly. Island species communities exist in complex dynamic equilibria with the surrounding oceanographic conditions. Energy fluxes and element cycles of the atoll system readily cross habitat boundaries and create a productive, diverse, and biomass-rich ecosystem on land and underwater. Past human disturbances and future global change put atolls at the forefront of conservation and ecological restoration.

Response of grassland greenhouse gas emissions to different human disturbances – A global Meta-analysis

Human disturbances have increased greenhouse gas (GHG) emissions from grassland, worsening global warming. However, the response of grassland GHG (CO2, N2O, and CH4) to human disturbances across various climatic zones requires further elucidation, as does the intricate relationship between GHG emissions and temperature and precipitation. A Meta-analysis of the effects of human disturbances on GHG in grassland over the past 40 years revealed that grazing, fertilization, mowing, and burning significantly influenced the total emissions of N2O, CH4, CO2, and GHG from grassland. However, the light and moderate grazing exerted no substantial impact on CO2 emission flux. In frigid zone grassland, the N2O emission flux was most significantly affected by grazing, the CH4 emission flux affected by fertilization was higher than grazing, and the CO2 emission flux was more sensitive to heavy grazing than severe fertilization. In temperate grassland and savanna, GHG emission flux was most sensitive to fertilization, with CO2 emission flux in savanna being particularly responsive to burning. The effect of increased temperature and precipitation on CO2e in fertilized grassland was approximately double that of grazed grassland and quadruple that of mowed grassland. This study emphasizes the increased effect of human disturbances on GHG emissions in the grassland, especially with the most significant impact of fertilization disturbances on GHG emissions in most grassland areas. Lowering the level of fertilization during grassland management could serve as a crucial step in mitigating GHG emissions from grassland. In summary, rigorous control of disturbance intensity represented an effective strategy for mitigating greenhouse gas emissions, albeit potentially impacting grassland productivity. Future endeavors should focus on determining the optimal disturbance intensity to strike a balance amidst these complex effects.

Atlantic Forest Regeneration Dynamics Following Human Disturbance Cessation in Brazil

The Brazilian Atlantic Forest (BAF) is one of the most important biodiversity hotspots and species-rich ecosystems globally. Due to human activities, it has been significantly reduced and fragmented. This study examined both biotic (floristic composition, diversity, and structure) and abiotic (topographic and soil) factors in BAF fragments undergoing varying levels and durations of human disturbance cessation: approximately 20 years (20 y), ~30 years (30 y), and over 40 years (>40 y). We aimed to understand the recovery dynamics of floristic composition, diversity, and structure in BAF fragments in relation to abiotic factors. Several statistical tools were employed to examine similarities/differences and relationships. Forests of the 30 y group exhibit significantly greater homogeneity in terms of floristic composition, while forests of the 20 y group are characterized by lower species abundance and diversity. The floristic composition was primarily influenced by soil features and the time of disturbance. Under “Environmental Protection Areas”, soil–vegetation recovery can occur more swiftly than usually observed for BAF. A significant BAF recovery was observed approximately 40 years after the end of human disturbance. A partial recovery featured 30 y disturbed areas, while in 20 y forests, recovery is in its early stages. Human-disturbed BAF can gradually rebound when effective management practices are implemented.

Assessment of Changes in the Composition and Distribution of Large and Medium-Sized Mammals in Xishuangbanna, Southwest China.

Given the vulnerability of large and medium-sized mammal communities to climate change and human disturbances, understanding the spatial-temporal dynamics of these communities is essential for effective conservation planning. However, in many biodiversity hotspots, precise biological community assessments are insufficient. From 2012 to 2022, we deployed 784 camera traps in eight nature reserves (including sub-reserves) and one State Forest Farm (SFF, less strictly protected than a reserve) to study the composition and distribution of large and medium-sized mammals in tropical Xishuangbanna. The findings revealed the following: (1) Forty-three species, encompassing six orders, 17 families, and 37 genera, were documented. Among the species in historical data, nine species were not detected in this survey. (2) Smaller and more fragmented reserves lacked larger body-sized predators and herbivores, and most common species showed lower relative population abundance. Conversely, the SFF exhibited high mammal diversity. (3) The community composition of large and medium-sized mammals varied significantly across the nine sites, particularly among threatened species. Our findings highlight the uneven distribution of these mammal communities in Xishuangbanna, with rare and large-sized species facing increased vulnerability to rapid environmental changes. Moreover, the findings demonstrate the importance of considering species specificity and uniqueness in conservation planning for maintaining regional-scale biodiversity.

Mowing mitigates the negative impacts of long-term warming on community composition and niche characteristics of alpine meadow on the Tibetan Plateau

Climate warming and human disturbance are supposed to have significantly impacted the alpine grasslands. However, it is still unclear how human activity affects the community composition and niche characteristics in response to warming. We conducted a two-factorial experiment in an alpine meadow, and set up four treatments: warming, mowing, warming with mowing, and control. Based on the investigation of community composition and niche characteristics, we evaluated the impacts of soil carbon, nitrogen, and phosphorus on species niche overlap. The results showed that mowing significantly increased species richness of Grass, Sedge, Forbs and the importance value of Sedge compared to warming (P < 0.05). The niche breadth of species (>50%) was reduced by warming, but increased under mowing. The niche overlap mainly occurred between Grass and Forbs in warming, while it was evenly distributed among species after mowing, which alleviated the negative effects of warming on interspecific competitiveness. Warming increased the number of species pairs with a niche overlap value >0.9 by 24.15%, while warming with mowing decreased it by 2.7%. The number of species pairs with niche overlap was significantly correlated with soil total nitrogen and soil available nitrogen (P < 0.05). In particular, the species pairs with highly competitive showed a greater dependency on soil nitrogen. Our work highlights that moderate utilization and soil nitrogen are two crucial factors influencing the response of community structure in alpine meadows to future climate change. The study provides an important reference for predicting and addressing the impact of global climate change on adaptive management and grassland protection.

Light-demanding canopy tree species do not indicate past human disturbance in the Yangambi rainforest (Democratic Republic of the Congo)

Key messageIn a former paper, we investigated whether the presence of light-demanding tree species in the forest canopy of the Yangambi Biosphere Reserve (central Congo basin) might be a result of past human disturbances (Luambua et al., Ecol Evol 11:18691–18707, 2021). We focussed on the spatial distribution of the most abundant light demanders, but this approach did not yield conclusive results. In the present study, we focus on all species in the forest and conclude that light demanders are not a transient feature of successional tropical forests but an intrinsic component of old-growth forests in Yangambi.ContextCentral African rainforests are characterised by an abundance of light-demanding tree species, which are aggregated in the canopy but underrepresented in the understorey. A popular explanation is that these forests are recovering from slash-and-burn farming activities preceding the relocation of settlements during the colonial era. In a former paper, we showed that the abundance of light-demanding tree species in the Yangambi Biosphere Reserve (central Congo basin) cannot be unambiguously attributed to past human disturbances, using an approach that focused on the spatial distribution of the most abundant light demanders (Luambua et al., Ecol Evol 11:18691–18707, 2021).AimsAs the former study was inconclusive, the present study aims to further test the assumptions behind the ‘recovery from human disturbance hypothesis’, by considering all species in the forest of Yangambi. We addressed four specific research questions: (i) do light demanders occur in large ‘pockets’ occupying large areas of forest? (ii) Are light demanders abundant? (iii) Do they exhibit a regeneration deficit? (iv) Is species composition in pockets of light demanders different from the surrounding forests?MethodsWe identified the location and size of pockets of light demanders in several transects cumulating to 50 km. We installed permanent inventory plots within and outside these pockets and calculated the diameter and age distributions of light demanders within each pocket. We assessed whether pockets of light demanders are different from surrounding forests, using plot clustering analysis.ResultsOur results showed that light demanders were aggregated, but the pockets were small, scarce, and represent a minor fraction of the total forest area. Furthermore, light demanders were not abundant, even in pockets where they were aggregated. Their age distributions did not show a regeneration deficit. Finally, species composition in pockets of light demanders did not differ substantially from surrounding forests where they were scarce or absent.ConclusionsWe conclude that light-demanding canopy species do not indicate past human disturbance in Yangambi and that they are an intrinsic component of old-growth forests rather than a transient feature of successional forests. Our insights show that the large carbon sink observed in mature forests in this region is not driven by successional forest dynamics.

Important Crop Pollinators Respond Less Negatively to Anthropogenic Land Use Than Other Animals.

Animal-mediated pollination is a key ecosystem service required to some extent by almost three-quarters of the leading human food crops in global food production. Anthropogenic pressures such as habitat loss and land-use intensification are causing shifts in ecological community composition, potentially resulting in declines in pollination services and impacting crop production. Previous research has often overlooked interspecific differences in pollination contribution, yet such differences mean that biodiversity declines will not necessarily negatively impact pollination. Here, we use a novel species-level ecosystem service contribution matrix along with mixed-effects models to explore how groups of terrestrial species who contribute differently to crop pollination respond globally to land-use type, land-use intensity, and availability of natural habitats in the surrounding landscape. We find that the species whose contribution to crop pollination is higher generally respond less negatively (and in some cases positively) to human disturbance of land, compared to species that contribute less or not at all to pollination. This result may be due to these high-contribution species being less sensitive to anthropogenic land conversions, which has led humans to being more reliant on them for crop pollination. However, it also suggests that there is potential for crop pollination to be resilient in the face of anthropogenic land conversions. With such a high proportion of food crops requiring animal-mediated pollination to some extent, understanding how anthropogenic landscapes impact ecological communities and the consequences for pollination is critical for ensuring food security.

Seaweed functional strategies, functional groups, and taxon dynamics through a 213-year historical series of Rio De Janeiro Bay

From Darwin’s visit to nowadays, we analyzed the changes in species- and genus-level richness and turnover, equity, diversity, composition, as well as functional group and functional strategy dynamics over a 213-year historical series of the seaweed assemblage from Rio de Janeiro Bay. We developed new analysis methods to serve as a protocol for worldwide functional and bioindicator assessment of seaweed assemblages. Over the two centuries of changes tracked, the integration of taxonomic, functional group, and functional strategy analyses unraveled a trajectory of seaweed assemblage restructuring under human disturbance. Our taxonomic analyses showed a high species and genus turnover and a decline in richness, with the local extinction of the Sargassum genus, responsible for warm temperate kelp forests in the Western Atlantic. Seaweed functional group data presented a trend of morphological simplification and miniaturization, with the decline of marine forest canopy and subcanopy-forming groups favoring filamentous and crustose algae dominance. Functional strategy data showed the historical decline of competitive structuring as an assemblage driver in favor of disturbance and stress-structuring, as highlighted by the competitive strategy decrease, coupled with stress-tolerant and ruderal strategies rise across metrics. These changes were successfully portrayed by the new ecological index we proposed, the C/SR index. It is the first quantitative index for seaweed assemblages, designed to be a trackable metric for conservation, monitoring, and restoration efforts.

Cougar spatiotemporal response to human activities in a multi‐use forest landscape on southern Vancouver Island

Recreational activities have been shown to induce fear responses in carnivores, causing both spatial and temporal displacement that can have cascading effects on the wider ecological community. Cougars Puma concolor are one species that are particularly sensitive to human disturbances as they have been found to be impacted by various forms of recreational activities. This research aimed to quantify the spatial and temporal responses of cougars to human activities on southern Vancouver Island in British Columbia, Canada. Fifty camera traps were deployed in a systematic probabilistic sampling design and data from the summer season of 2022 was used for analyses. We modeled cougar weekly occurrence frequency in relation to human (hikers and bikers) occurrence frequency, vehicle occurrence frequency, and landscape features, using generalized linear mixed models. Temporal responses of cougars were investigated using activity pattern analysis to compare activity patterns within a recreation area and a restricted public access reserve. Cougars avoid occurring at sites where recreationalists frequently visited, but not sites frequented by vehicles on unpaved roads. We observed minimal influence of habitat features or prey availability on cougar occurrence frequency, as measured by information loss (AICc scores). Activity pattern analysis did not demonstrate significant differences in cougar daily activity patterns between the recreation area and no‐entry reserve, suggesting a lack of temporal response. These results suggest recreational activities on southern Vancouver Island are impacting cougar spatial – but not temporal – behavioral dynamics. Insights on how cougars respond to recreational activities can help inform landscape management and policies by providing information that can be used to mitigate negative impacts and thus ensure that recreational activities are remaining compatible with conservation efforts.

Effects of human disturbance on the distribution and abundance of large mammals in Abijata-Shalla Lakes National Park, Ethiopia

The increasing human pressure has threatened wildlife conservation, even in protected areas. However, findings reporting the effects of human on wildlife conservation are not consistent. This study aimed to investigate the effect of human disturbance on the distribution and abundance of mammals in Abijata-Shalla Lakes National Park considering the consumptive and non-consumptive modes of human activities. The study was conducted from September 2017 to February 2018 in three selected sites, which were stratified based on human disturbance as nature conserved areas, sites engaged in consumptive livelihood, and ecotourism sites. Data were collected using a line transect method. The distribution and abundance data were analyzed using Chi-square tests and one-way ANOVA, respectively. There was a significant difference on the distribution of target wild animals in the selected sites; greater kudu (P < 0.001), warthog (P < 0.01), and bohor reedbuck (P = 0.03) were highest in the “nature conserved” site. Human disturbance also significantly affected the abundance of warthog (P = 0.028), greater kudu (P < 0.001), and bohor reedbuck (P = 0.024). Greater kudu distribution was limited in nature conserved site. However, Warthog and Bohor Reedbuck were distributed in all sampling sites; nature conserved sites hold the highest population abundance. The results indicate that consumptive local livelihood and ecotourism disturbances adversely affected the distribution and abundance of mammals relative to the nature reserved site. However, ecotourism favored some mammal species from the consumptive local people’s livelihood activities. Thus, to reduce the impact of human disturbances on wildlife conservation, monitoring and controlling the level of human disturbance is urgent. Sustainable practices such as community engagement, awareness creation and alternative livelihood options should be proposed.

Influence of stream temperature and human disturbance on prespawn mortality of Chinook Salmon in the Willamette River basin

AbstractObjectivePremature mortality of adult female Chinook Salmon Oncorhynchus tshawytscha is a major barrier to population recovery. The Willamette River basin, Oregon, typifies the problems that are faced by fishery managers in the Pacific Northwest (USA). Adult salmon are trapped and transported upstream of dams to access historical spawning grounds, but annual rates of prespawn mortality (PSM) are high (often &gt;40%) and may limit the recovery of natural populations. The purpose of this study was to identify potential factors related to PSM of female Chinook Salmon that are outplanted above dams and incorporate them into a modeling framework to facilitate adaptive management of outplanting operations.MethodsWe evaluated PSM in Fall Creek of the Willamette River basin prior to transport facility improvements in summer and fall of 2010–2017 and postimprovement during 2020–2021. We estimated PSM and conducted exploratory analyses to identify possible nontransport sources of stress that may contribute to the observed high PSM rates. Candidate factors included long‐term elevated temperature exposure, elevated temperature exposure below the trap, total number of outplanted fish, and monthly human disturbance of outplanted fish. We then developed and fit three models, each representing a hypothesis of a factor influencing PSM, incorporated them into a single alternative decision model, and conducted sensitivity analyses.ResultPrespawn mortality averaged 0.66 (ranging from 0.37 to 0.94) over the study period. According to the simulation results, the top two management actions were to exclude human activities—swimming and fishing—from Fall Creek in July and August.ConclusionExpected PSM rates were predicted to be 0.38 when human activity was excluded in July and 0.37 for August. Sensitivity analyses indicated that the most influential decision model component was the choice of the alternative model.

Variation in diurnal and nocturnal movements distances revealed in wintering dabbling ducks in the Mississippi Alluvial Valley

Movement of waterfowl during winter is central to resource acquisition and mortality avoidance, despite the imminent risk to survival and overall fitness induced by hunting disturbance and energy expenditure. Weather and other environmental conditions may influence movement by altering resource needs, in which ducks must balance the trade‐offs of resource acquisition and risk management. We compared how environmental factors influenced total daily diurnal and nocturnal movement distances of three dabbling duck species wintering in the Mississippi Alluvial Valley. We estimated total daily diurnal and nocturnal movement distances of green‐winged teal (Anas crecca; n = 51), American wigeon (Mareca americana; n = 38), and mallards (Anas platyrhynchos; n = 31) using backpack transmitters during the winter period of February–November 2020–2021 and 2021–2022. We used linear mixed effects models to model the influence of weather, hunt season, day of season, and sex on total diurnal and nocturnal movement distances by species. Green‐winged teal moved 7.7% further during the nocturnal period (x̅ = 3.38 km; SE = 0.32; p &lt; 0.001) than during the diurnal period (x̅ = 3.13 km SE = 0.10), while American wigeon and mallards moved 36.6% (x̅ = 4.95 km; SE = 0.20; p &lt; 0.001) and 28.1% (x̅ = 4.39 km; SE = 0.23; p &lt; 0.001) further during the diurnal period than the nocturnal period (x̅ = 3.42 km, SE = 0.28 and x̅ = 3.31 km, SE = 0.22), respectively. Fine‐scale movement distances during the diurnal period were weakly associated with environmental covariates for all species. Conversely, moon illumination influenced nocturnal movement distances for all species. Nightly movement distances of mallards increased by 2.1 times from new to full moon during the hunting season. Conversely, there were no changes in nocturnal movement distance during pre‐hunt and post‐hunt periods when hunting disturbance was absent. In the face of intensifying environmental pressures on movement patterns in dabbling duck populations, this research demonstrates a behavioral response to moon illumination as a mechanism for moving about the landscape for resource acquisition in the presence of human disturbances that induce risk, such as hunting.

Intact, under-patrolled forests harbor widespread prey but a male-biased tiger population in the Ulu Masen Ecosystem, Sumatra, Indonesia

Conservation of threatened species is dependent on consistent population monitoring. We present the first status assessment of critically endangered Sumatran tigers (Panthera tigris sumatrae) and their prey in the Ulu Masen Ecosystem, Aceh, Indonesia. Our estimates of tiger habitat use are the first reported for a Sumatran ecosystem unprotected at the national level. During 6,732 trap nights accumulated over 23 months of camera-trap monitoring in 2020 and 2022, tigers were detected 39 times at 16 of the 52 stations. We identified 11 individual tigers but sex ratios were highly skewed: 8 males, 1 female, and 2 individuals of unknown sex. Cubs were not photographed either year and we did not observe evidence of tiger reproduction. Tiger habitat use (Ѱ = 0.52, SE = 0.15) was negatively influenced by human disturbance and positively influenced by elevation but those associations were not significant. Our study documents a widespread prey base but uncovers demographic characteristics of tigers indicative of heavy poaching pressures. We conclude that tiger-targeted protection is urgently needed to ensure the species’ persistence in Ulu Masen which, together with the adjacent Leuser Ecosystem, represents the largest contiguous tiger conservation landscape remaining in Sumatra.

Identification and assessment of the mudflat ecological vulnerability dominated by coastline evolution in Jiangsu

Coastlines have experienced profound alterations due to human disturbances and ocean dynamics against the backdrop of climate change and intensified anthropogenic activities. Significant modifications have occurred within the muddy coastal ecosystem, rendering it extremely susceptible to heightened levels of vulnerability. However, existing studies on coastal eco-environmental vulnerability have often overlooked crucial factors such as coastline erosion and siltation, particularly concerning coastline change. In this study, we assess coastline stability utilizing Landsat remote sensing imagery to investigate the vulnerability of coastal ecology alongside 24 economic and natural parameters, serving as indices for the Coastal Vulnerability Index (CVI) of the coastal eco-environment. Subsequently, we analyze the impact factors to vulnerability and predict trends in coastline change over the next 20 years to propose recommendations for sustainable development to safeguard the coastal eco-environment. Our findings reveal a trend towards coastline stabilization in Jiangsu, with significantly higher stability observed during 2010–2020 compared to 1985–2010. The overall CVI along the Jiangsu coast shows an downward trajectory over the past 15 years, primarily influenced by tidal action and coastal topography and geomorphology. Predictive modeling suggests Jiangsu coastline is bounded by the Sheyang estuary, with the coastline to the north dominated by stabilization and to the south dominated by siltation. Climate change, coupled with intensified human activities and future coastline alterations, may exacerbate vulnerability. Effective protection strategies for coastal ecosystems necessitate a comprehensive understanding of local natural conditions, resource availability, and socioeconomic dynamics. Governmental interventions should focus on reinforcing regulatory frameworks for coastal organism management, implementing coastal protection infrastructure, and enhancing supervision and management protocols for beachfront development, thereby fostering the sustainable management of muddy coastlines.