Effects Of Anthropogenic Disturbance Research Articles

Simulated poaching affects global connectivity and efficiency in social networks of African savanna elephants-An exemplar of how human disturbance impacts group-living species.

Selective harvest, such as poaching, impacts group-living animals directly through mortality of individuals with desirable traits, and indirectly by altering the structure of their social networks. Understanding the relationship between disturbance-induced, structural network changes and group performance in wild animals remains an outstanding problem. To address this problem, we evaluated the immediate effect of disturbance on group sociality in African savanna elephants-an example, group-living species threatened by poaching. Drawing on static association data from ten free-ranging groups, we constructed one empirically based, population-wide network and 100 virtual networks; performed a series of experiments 'poaching' the oldest, socially central or random individuals; and quantified the immediate change in the theoretical indices of network connectivity and efficiency of social diffusion. Although the social networks never broke down, targeted elimination of the socially central conspecifics, regardless of age, decreased network connectivity and efficiency. These findings hint at the need to further study resilience by modeling network reorganization and interaction-mediated socioecological learning, empirical data permitting. The main contribution of our work is in quantifying connectivity together with global efficiency in multiple social networks that feature the sociodemographic diversity likely found in wild elephant populations. The basic design of our simulation makes it adaptable for hypothesis testing about the consequences of anthropogenic disturbance or lethal management on social interactions in a variety of group-living species with limited, real-world data.

EFFECT OF HUMAN DISTURBANCES ON ANT COMMUNITY AND AMAZONIAN LANDSCAPE

The present work aimed to evaluate the effect of anthropogenic disturbances on the ant community and on the Amazonian landscape in areas of tropical rain forest. The study was conducted in two areas: Cabo Rosa Forest and Tauari Forest with different levels of human disturbances in the municipality of Marabá, Pará, Brazil. A characterization of the descriptors of anthropogenic activities was carried out for each study area in order to generate an index of anthropogenic disturbance. The vegetation structure was classified into: exposed soil, low, medium and high vegetation cover through NDVI. Ant sampling was carried out using pitfall traps. The vegetation structure, diversity and abundance parameters were related to the areas. Similarities between the species composition of the ant communities were verified by a similarity analysis. We found that human disturbances are modifying the vegetation structure by reducing the forest cover of the tree stratum and leaving the landscape with a higher occurrence of open areas. Regarding the ant community, we corroborate the hypothesis that anthropic disturbances are reducing the local biodiversity. Thus, this study shows that anthropogenic disturbances have negative effects on the Amazonian landscape and on the ant community through the reduction of forest cover and decrease in ant biodiversity. These changes can cause the conversion of climax communities in early successional stages and reduce the ecological services provided by ants (e.g. seed dispersal).

Loss of plant cover mediates the negative effect of anthropogenic disturbance on the multifunctionality of a dryland

AbstractAimsAnthropogenic disturbances due to human economic activities may affect ecosystem services, which are the benefits provided by the ecosystem properties, such as soil water content and soil fertility. Also, these disturbances affect plant community biodiversity and cover, which are also known to affect multiple ecosystem properties. However, the strength of the relative effects of the disturbance itself and of the effect that is mediated by changes in the plant community is still unclear.QuestionsWe evaluated the relative direct and indirect effects (mediated by changes in the plant community) of the anthropogenic disturbances on ecosystem multifunctionality.LocationDry forests within the Sustainable Development Reserve Ponta do Tubarão, northeastern Brazil.MethodsWe measured standing biomass, litter mass, soil fertility and soil water content in 52 vegetation plots along a gradient of anthropogenic disturbance. Also, we measured woody plant cover and species’ functional traits to characterize the plant community functional structure. We measured livestock grazing, selective logging and past clear‐cuts as proxies of anthropogenic disturbance to create an index that characterizes the additive effect of these human activities. By building a theoretical model using the structural equation modelling approach, we investigated how the plant community changes in cover and biodiversity due to anthropogenic disturbances mediate changes in ecosystem properties.ResultsOur results show that anthropogenic disturbances had negative effects on ecosystem properties. Plant cover loss caused by anthropogenic disturbances was the major determinant of the negative effect of disturbances. The functional structure of the plant community had a weak effect on these properties.ConclusionsBy assessing the effect of human activities on multifunctionality, we found a stronger negative effect of anthropogenic disturbances when compared to its effect on single ecosystem properties. The recovery of plant cover should be a major focus of projects aiming to restore and maintain the multifunctionality of this dryland.

Floristic Composition and Diversity in Response to Varying Degrees of Disturbance in Tropical Dry Deciduous Forests of Southern Haryana, India

The aim of the current investigation was to study the effects of anthropogenic disturbances on the vegetation structure of the three Tropical Dry Deciduous Forests of Southern Haryana i.e., Mandhana, Ghasola, and Mandhiali in the Bhiwani, Charkhi Dadri, and Mahendergarh districts, respectively. The data were collected from March, 2020 to March, 2021. The floristic composition was quantified by randomly placing 15 quadrats per site (45 in total). A disturbance index was developed for each site and high, medium and low disturbance areas were identified based on prevailing disturbances that were found to be maximum for Mandhiali (21), followed by Ghasola (16) and Mandhana (9). Ecological parameters such as frequency, density, abundance, basal area, IVI, and diversity indices were calculated for each siteduring the study. A total of 50 species of plants representing 44 genera and 25 families were observed consisting of 14 trees, 9 shrubs, and 27 herbs during the investigation of floristic composition. The species richness decreased with an increase in the disturbance level on the three sites viz., Mandhana (40), Ghasola (33), and Mandhiali (29) respectively. The value of Shannon Weiner diversity index (H’) and Pielou Index of evenness (E) declined with an increasing disturbance while Simpson index of dominance (Cd) increased as the disturbance levels increased across the three sites. The results offer significant evidence that anthropogenic disturbances in arid regions of South Haryana play a vital role in community structure and composition. In a forest ecosystem, anthropogenic disturbances cause habitat fragmentation along with soil erosion, loss of soil fertility and biodiversity, etc. The selected forests are in urgent need of management activities to check the intensity of disturbances by controlling anthropogenic pressure on these ecosystems and save them from further degradation. Thus, the present study intensifies the need for phytosociological studies crucial for proper management and conservation purposes.

Effect of disturbances and habitat fragmentation on an arboreal habitat specialist mammal using GPS telemetry: a case of the red panda.

ContextHabitat specialists residing in human-modified landscapes are likely to be more vulnerable to disturbance because of a functional reliance on very particular habitat features. However, there have been few studies designed to specifically address that issue.ObjectivesThis study aimed to explore how the red panda, an iconic endangered habitat specialist, behaves when faced with disturbances and habitat fragmentation. In particular, we attempted to examine the effect of anthropogenic disturbances and fragmentation on home-range size, activity patterns, and recursion.MethodsUsing GPS telemetry we monitored 10 red pandas and documented disturbances using camera trapping for one year in eastern Nepal. We performed spatial analysis, analysed activity patterns and evaluated the effect of habitat fragmentation and disturbances on home-range size and residence time using Linear Mixed Models.ResultsHome-range size increased in areas with low availability of forest cover whilst home ranges were smaller in areas with a high road density. Red pandas spent more time in large habitat patches away from roads and cattle stations. Crossing rates suggested that roads acted as a barrier for movement across their habitat. Red pandas also partitioned their activity to minimize interactions with disturbances.ConclusionsRed pandas seem to make a trade-off to co-exist in human-dominated landscapes which may have adverse long-term effects on their survival. This indicates that current patterns of habitat fragmentation and forest exploitation may be adversely affecting red panda conservation efforts and that landscape-scale effects should be considered when planning conservation actions.Supplementary InformationThe online version contains supplementary material available at 10.1007/s10980-021-01357-w.

Effects of anthropogenic disturbance on seed germination under field conditions: A meta-analysis

Anthropogenic disturbances, such as habitat fragmentation, edge effects, biological invasions, and selective logging, can affect abiotic conditions and biotic interactions that influence the likelihood of seed germination, an important bottleneck for plant regeneration. However, there is no research synthesis evaluating the impact of those disturbances on germination. We performed a global meta-analysis comparing seed germination on disturbed and undisturbed sites. We evaluated the influence of disturbance type, vegetation, plant growth form, dispersal syndrome, seed mass, climate region and phylogeny on germination responses to disturbance. We obtained information about 74 plant species from 25 studies. We found an overall negative effect of anthropogenic disturbance on seed germination. Biological invasion and habitat fragmentation presented a negative impact, whilst edge effects, selective logging and grazing had no consistent effect on seed germination. Anthropogenic disturbances decreased germination of forest species, but plants from open physiognomies (savannas, shrublands and grasslands) were not consistently affected. Disturbed conditions decreased germination of understory forest herbs and shrubs from open physiognomies. Germination of abiotic-dispersed plants was decreased in disturbed areas, whilst there was no consistent effect on biotic-dispersed ones. Seed mass had no effect on species responses, but the interactions between seed mass and growth form and dispersal syndrome affected germination responses. Species responses did not differ between tropical and temperate regions. Phylogenetic relationships among species did not drive the results. Anthropogenic disturbances generally decrease seed germination, and non-trees, small-seeded and abiotic dispersed plants are the most affected. Therefore, conservation practices or restoration efforts focusing on early recruitment, such as direct sowing of seeds, should pay special attention to decreases in seed germination due to habitat alterations following disturbances. Amelioration of disturbed conditions, such as control of invasive species, should be considered to maintain germination rates and plant regeneration in long-term.

Degree of Anthropogenic Land Disturbance Controls Fluvial Sediment Hysteresis.

Storm events dominate sediment delivery to stream corridors, but the effects of anthropogenic disturbances on altering the sources, pathways, and timing of delivery remain uncertain. To address this knowledge gap, we analyzed 849 events from over a decade of high-frequency turbidity data across five watersheds in an urbanization gradient. Sensing results suggested that hysteresis patterns evolved with land use from clockwise (low-rural) to figure-eight (high-rural) to counter-clockwise (high-urban), indicating a disturbance-driven shift of sediment provenance from proximal to distal. Sediment loading pathways in the lowest-disturbance rural watershed were dominated by a single hysteresis shape (>90% of export by clockwise events), whereas the most-disturbed urban basin had the greatest variability in loading pathways (∼25% of export by clockwise, counter-clockwise, figure-eight, and complex events, respectively). Finally, wastewater treatment facilities modulated the release of "hungry-water" baseflow, causing more-rapid periods of high streamflow variance in catchments with a treatment facility (∼4 h period) than in those without (∼6 h period). Together, our results indicate that anthropogenic disturbances, including tile drainage, impervious surfaces, and roadway density, increase the connectivity of distally located sediment that would-in undisturbed basins-deposit along the sediment cascade. This information is important to watershed managers as they mitigate erosion in developing basins.

Railways redistribute plant species in mountain landscapes

Abstract The significant portion of global terrestrial biodiversity harboured in the mountains is under increasing threat from various anthropogenic impacts. Protecting fragile mountain ecosystems requires understanding how these human disturbances affect biodiversity. As roads and railways are extended further into mountain ecosystems, understanding the long‐term impacts of this infrastructure on community composition and diversity gains urgency. We used railway corridors constructed across the mountainous landscapes of the Kashmir Himalaya from 1994 to 2013 to study the effects of anthropogenic disturbance on species distributions and community dynamics. In 2014 and 2017, we collected vegetation data along 31 T‐shaped transects laid perpendicular to the railway line, adopting the MIREN (Mountain Invasion Research Network) road survey methodology. Plant communities shifted significantly from 2014 to 2017, potentially because of an ongoing species redistribution after railway construction, driven mainly by declines in both native and non‐native species richness, and an increasing abundance of a few non‐native species, especially in areas away from the railway track. These patterns indicate an advancing succession, where initially—rare—pioneer species are replaced by increasingly dominant and often non‐native competitors, and potentially suggest a trend towards delayed local extinctions after the disturbance event. Native and non‐native species richness was negatively correlated with elevation, but that relationship diminished over time, with the abundance of non‐natives significantly increasing at higher elevations. Synthesis and applications. Transport corridors seem to facilitate the spread of non‐native species to higher elevations, which has serious implications considering the warming mountain tops. Our results indicate that the plant communities next to railways do not reach equilibrium quickly after a disturbance. More than 10 years after railway establishment within Kashmir Himalaya, succession continued, and signs pointed towards a landscape increasingly dominated by non‐native species. Our study indicates that the single disturbance event associated with constructing railway in this Himalayan region had large and long‐lasting effects on plant communities at and around this transport corridor and suggests the need for a long‐term region‐wide coordinated monitoring and management program.

Far-Field Effects of Impulsive Noise on Coastal Bottlenose Dolphins

Increasing levels of anthropogenic underwater noise have caused concern over their potential impacts on marine life. Offshore renewable energy developments and seismic exploration can produce impulsive noise which is especially hazardous for marine mammals because it can induce auditory damage at shorter distances and behavioral disturbance at longer distances. However, far-field effects of impulsive noise remain poorly understood, causing a high level of uncertainty when predicting the impacts of offshore energy developments on marine mammal populations. Here we used a 10-year dataset on the occurrence of coastal bottlenose dolphins over the period 2009–2019 to investigate far-field effects of impulsive noise from offshore activities undertaken in three different years. Activities included a 2D seismic survey and the pile installation at two offshore wind farms, 20–75 km from coastal waters known to be frequented by dolphins. We collected passive acoustic data in key coastal areas and used a Before-After Control-Impact design to investigate variation in dolphin detections in areas exposed to different levels of impulsive noise from these offshore activities. We compared dolphin detections at two temporal scales, comparing years and days with and without impulsive noise. Passive acoustic data confirmed that dolphins continued to use the impact area throughout each offshore activity period, but also provided evidence of short-term behavioral responses in this area. Unexpectedly, and only at the smallest temporal scale, a consistent increase in dolphin detections was observed at the impact sites during activities generating impulsive noise. We suggest that this increase in dolphin detections could be explained by changes in vocalization behavior. Marine mammal protection policies focus on the near-field effects of impulsive noise; however, our results emphasize the importance of investigating the far-field effects of anthropogenic disturbances to better understand the impacts of human activities on marine mammal populations.

Ecological aspects of mosquitoes (Diptera: Culicidae) in a fragment of seasonal dry tropical forest (Caatinga) in Brazil

Seasonally dry tropical forests are among the most vulnerable ecosystems to the effects of anthropogenic disturbances, and yet their biodiversity is still poorly known. In this study we investigated the composition, activity, structure, and effect of seasonality in mosquitoes’ assemblages of a conservation Caatinga domain unit. The collections consisted of the monthly installation of two Shannon traps, set at a distance of 8 km between them, and operated by two captors, who collected simultaneously for 3 h (17:00h to 20:00h), totaling 288 h of sampling over two years. In total, 1261 specimens belonging to at least 20 sp. of the subfamilies Anophelinae and Culicinae were captured. Culicinae was the most representative subfamily, with 99.3% of all collected specimens, while for Anophelinae only nine specimens of the species Anopheles albitarsis Lynch Arribálzaga, 1878 s.l. were registered. Among the species of Culicinae, Aedes scapularis was the most abundant (39.9%), followed by Mansonia wilsoni (21.6%), Culex spp. (12.8%) and Aedes taeniorhynchus (12.4%). The Culicidae assemblage was more abundant and diverse in the wettest months and the twilight hours (17:00h to 18:00h). Our data indicate that Anopheles species are sensitive to Caatinga arid conditions and that mosquito populations are controlled by rainfall.

Illegal harvesting and livestock grazing threaten the endangered orchid Dactylorhiza hatagirea (D. Don) Soó in Nepalese Himalaya.

Harvesting of orchids for medicine and salep production is a traditional practice, and increasing market demand is spurring illegal harvest. Ethno‐ecological studies in combination with the effect of anthropogenic disturbance are lacking for orchids. We compared population density and structure, and tuber biomass of Dactylorhiza hatagirea (D. Don) Soó for three years in two sites: Manang, where harvesting of medicinal plants was locally regulated (protected), and Darchula, where harvesting was locally unregulated (unprotected). Six populations were studied along an elevation gradient by establishing 144 temporary plots (3 × 3 m2) from 3,400 to 4,600 m elevations. Mean density of D. hatagirea was significantly higher in the locally protected (1.31 ± 0.17 plants/m2) than in the unprotected (0.72 ± 0.06 plants/m2) site. The protected site showed stable population density with high reproductive fitness and tuber biomass over the three‐year period. A significant negative effect (p < .1) of relative radiation index (RRI) on the density of the adult vegetative stage and a positive effect of herb cover on juvenile and adult vegetative stages were found using mixed zero‐inflated Poisson (mixed ZIP) models. The densities of different life stages were highly sensitive to harvesting and livestock grazing. Significant interactions between site and harvesting and grazing indicated particularly strong negative effects of these disturbances on densities of juvenile and adult reproductive stages in the unprotected site. Semi‐structured interviews were conducted with informants (n = 186) in the villages and at the ecological survey sites. Our interview results showed that at the protected site people are aware of the conservation status and maintain sustainable populations, whereas the opposite was the case at the unprotected site where the populations are threatened. Sustainability of D. hatagirea populations, therefore, largely depends on controlling illegal and premature harvesting and unregulated livestock grazing, thus indicating the need for permanent monitoring of the species.

Rapid weight loss in free ranging pygmy killer whales (Feresa attenuata) and the implications for anthropogenic disturbance of odontocetes

Understanding the impacts of foraging disruptions to odontocete body condition is fundamental to quantifying biological effects of human disturbance and environmental changes on cetacean populations. Here, reductions in body volume of free-ranging pygmy killer whales (Feresa attenuata) were calculated using repeated measurements of the same individuals obtained through Unoccupied Aerial System (UAS)-photogrammetry during a prolonged disruption in foraging activity arising from a 21-day stranding event. Stranded individuals were used to verify UAS-derived volume and length estimates through 3D-imaging, water displacement, and post-mortem measurements. We show that (a) UAS estimates of length were within 1.5% of actual body length and UAS volume estimates were within 10–13% of actual volume, (b) foraging disruption resulted in a daily decrease of 2% of total body mass/day, and (c) pygmy killer whales can lose up to 27% of their total body weight within 17 days. These findings highlight the use of UAS as a promising new method to remotely monitor changes in body condition and animal health, which can be used to determine the potential effects of anthropogenic disturbance and environmental change on free-ranging odontocetes.

Effect of forest fragmentation and disturbance on diversity and structure of woody species in dry Afromontane forests of northern Ethiopia

Anthropogenic disturbance and fragmentation have changed the structure and composition of northern Ethiopian forests. This study was conducted to determine disturbance levels of patches, and examine the effect of anthropogenic disturbance and fragment size on diversity and structural attributes of woody species. A systematic sampling method was used to collect data and 61 nested plots of each 400 m2 were used. The disturbance index was used to assess disturbance intensities. To examine the effects of fragment size and anthropogenic disturbances on woody species diversity and structure, regression analysis was performed. ANOVA was used to examine differences in woody species diversity and structural attributes among fragments. Similarities among patches were assessed by Sorensen’s similarity index. A total of 80 woody species, representing 68 genera and 43 families were recorded. Diversity, evenness, stem density ha−1, and basal area were 2.8 ± 0.47, 0.73 ± 1.10, 1171.21 ± 220.10, and 39.89 ± 17.47 m2 ha−1 respectively. The mean number of species, evenness, and diversity were significantly different among fragments. Diversity, evenness, the mean number of species, and stem density per hectare significantly increased with increasing fragment size. Disturbance intensities varied among fragments. However, the mean basal area, mean seedling, and sapling density per hectare were not significantly affected by patch size and disturbance intensities. Generally, forest fragmentation and anthropogenic disturbance resulted in the reduction of diversity, affect woody species structure, and increased the level of disturbance. Therefore, recognizing the role of small fragments for forest conservation, minimizing further disturbance, and undertaking restoration activities in disturbed patches are strongly needed.

Assessing Population-Level Effects of Anthropogenic Disturbance on a Marine Mammal Population

The Population Consequences of Disturbance (PCoD) model is a conceptual framework used to assess the potential for population-level consequences following exposure of animals to a disturbance activity or stressor. This framework is a four-step process, progressing from changes in individual behavior and/or physiology, to changes in individual health, then vital rates, and finally to population-level effects. Despite its simplicity, there are few complete PCoD models available for any marine mammal species due to a lack of data available to parameterize many of the steps. Here, we present an application of the PCoD framework for migrating humpback whales exposed to a simulated commercial seismic survey scenario. We approached the framework in two ways; first, progressing sequentially forwards through the steps and basing our assessment on lactating females. This cohort was considered to be the most vulnerable in terms of energetic costs of disturbance, and most likely to influence any change in population growth due to future breeding success. Field measurements of behavioral responses of migrating humpback whales to seismic air guns from a previous study were used to parameterize an agent-based model (ABM). This ABM was used to estimate the probability of response, where a response was defined as a change in the migratory movement of female-calf pairs, and the duration of any resulting delay in migration. We then estimated the energetic consequences of any delay in migration for the lactating females and created population growth models with which to assess any population-level effects. The results of the forwards approach suggested a low potential for population consequences of seismic surveys on migrating humpbacks. Working backwards through the framework, we investigated “worst case” scenarios that could potentially lead to a population-level effect. Here, we started with increasing calf mortality and assumed that an exposure time greater than 48 h would increase mortality risk. We determined the most likely context in which this exposure would occur (resting area) and then tested this context within an ABM. This backwards approach illustrates how the PCoD model can be used to make management decisions regarding animal populations and exposure to anthropogenic stressors.

Direct and Indirect Effects of Forest Anthropogenic Disturbance on Above and Below Ground Communities and Litter Decomposition

Direct and indirect effects of habitat modification and changes in biotic interactions should be taken into consideration to understand the ecological consequences of forest anthropogenic disturbance on forest ecosystems. Few empirical studies assess indirect effects and consider multiple trophic levels, but recent statistical and theoretical advances provide new paths to do so. Here, we investigate direct and indirect effects of anthropogenic disturbances on multi-trophic soil communities in a boreal forest. We assessed the short term (2 years) abiotic and biotic responses to two anthropogenic disturbance intensities: conventional harvesting and harvesting followed by organic matter removal. We quantified the changes on eight groups of species, including vegetation and soil fauna, and their potential effects on leaf litter decomposition. We used a trait-based approach and structural equation modeling to quantify direct and indirect effects of disturbance intensity on environmental conditions, functional responses of the above and below ground biotic communities and leaf litter decomposition. Forest disturbance intensity was found to have a bottom-up effect on species community composition, from lower trophic levels (for example, detritivorous springtails) up to soil fauna top predators (for example, running spiders). Our results suggested some impacts of disturbance on leaf litter decomposition through changes in faunal communities. Our study shows that a multi-trophic assessment of disturbance impacts provides an integrative understanding of ecosystem responses to environmental change.

The entangled multi-level responses of Mytilus galloprovincialis (Lamarck, 1819) to environmental stressors as detected by an integrated approach

Anthropogenic pressure adds up and interacts with the effects of climate change with a varying magnitude and potential changes depend on species’ Life History (LH) traits, local environmental conditions and co-occurrence of several stressors. Stressors exert negative effects on marine biota when acting as a single factor, but the effects may be amplified when more than one stressor work in combination, producing interacting effects on biodiversity and ecosystem functioning. The impairment of individual functional traits (FT) leads to strong rebounds on LH traits and this may have ecological consequences. No studies actually relate FT and antioxidant enzymes to multiple environmental stressors. In this paper we investigate the effects of food concentration, temperature and hypoxia on metabolic traits as expressed by a proxy such as respiration rate and feeding behaviour and on antioxidant enzymes (Catalase, Superoxide dismutase, Glutathione S-Transferase, Glutathione peroxidase) for the bivalve Mytilus galloprovincialis. Mussels were exposed to three temperatures (12, 20 and 28 °C) under normoxic (8 mg O2 l−1) and hypoxic (~2 mg O2 l−1) conditions, with varying food concentrations ranging from 0.9 to 3.5 μg of chlorophyll l−1. The results show that FTs and antioxidant enzymes were affected by temperature, hypoxia and food availability, and outcome allowed us to emphasise that a multi-scalar integrated approach is suitable to detect and monitor effects of anthropogenic disturbance on ecosystem functioning.

Does Substrate Quality Influence Diversity and Habitat Use of Waterbirds?: A Case Study from Wetlands in Southern India

Abstract Wetland acts as an important habitat that supports a massive diversity of organisms, especially waterbirds. We examined waterbird diversity and habitat use in relation to abiotic factors at Mavoor and Vazhakkad, two major wetlands in southwestern India. The study was carried out from 2015 December to 2016 November. A total of 50 species from Vazhakkad and 40 species from Mavoor wetlands were recorded; 12 species were exclusive to Vazhakkad and three to Mavoor. Among them, 16 species were winter visitors in Vazhakkad and nine in Mavoor. Highest diversity of waterbirds was observed in the agroecosystem of Vazhakkad. Physicochemical variables were recorded for the two wetlands, and their effect on waterbird richness, abundance and diversity were correlated. Multivariate analysis showed the variation in diversity between the two wetlands (MANOVA: Wilks’ λ = 0.933, F = 3.69, P = 0.006) and habitat wetland interaction (MANOVA: Wilks’ λ = 0.694, F = 10.25, P = 0.00). Nonlinear regression analyses were carried out between the evolution of the ecological index in the two wetlands separately. The present study could determine the effects of anthropogenic disturbances on wetland function from this study.

Fast invasives fastly become faster: Invasive plants align largely with the fast side of the plant economics spectrum

Abstract Invasive plants generally align with the fast side of the plant's trait economics spectrum, characterized by fast nutrient acquisition, growth and reproduction. However, there are numerous and notable exceptions, including woody invasives. The generalization that invasives are fast is driven by the high occurrence of invasive ruderal species colonizing nutrient‐rich disturbed habitats, a consequence of anthropogenic disturbance usually going hand‐in‐hand with biological introductions. Successful invasive plans have shown a remarkable ability to rapidly adapt to the new regions where they are introduced. These changes predominantly involve increased resource acquisition, growth and reproduction, aligning them even further with the fast side of the plant economics spectrum. Common garden experiments with invasive model systems provide valuable insights about the speed and direction of adaptive responses to different climates, helping us to predict general plant responses to global change. Synthesis. Invasive plant species commonly present fast nutrient acquisition, growth and reproduction, but this general pattern is mostly driven by ruderal species. Still, common garden experiments comparing populations from distant world regions show a clear trend for already fast invasive plants to rapidly adapt towards even faster traits in their non‐native regions.

Spatial and temporal variations in stable isotope values (δ13C and δ15N) of the primary and secondary consumers along the southern coastline of the Caspian Sea

Spatial and temporal variations in stable isotope values of the coastal communities in the Caspian Sea remain poorly understood. We followed carbon stable isotope ratios (δ13C) and nitrogen stable isotope ratios (δ15N) of primary (gammarids) and secondary (common carp) consumers at four sites with different organic matter loadings along the southern coastline of the Caspian Sea from May to November 2019. Consumers from the site receiving higher sewage effluent and aquaculture wastes were more enriched in δ15N whereas those from the site receiving lower terrestrial-derived organic matter had enriched δ13C values. Trophic position of consumers varied among sites as a function of organic matter inputs but was independent of month. The observed temporal and spatial variations in the stable isotope values and C:N ratios of the primary and secondary consumers with regards to organic matter loadings, suggesting a possible effect of anthropogenic disturbance on the Caspian Sea ecosystem function.

A meta-analysis of anthropogenic impacts on physiological stress in wild primates.

As humanity continues to alter the environment extensively, comprehending the effect of anthropogenic disturbances on the health, survival, and fitness of wildlife is a crucial question for conservation science. Many primate populations occupy suboptimal habitats prone to diverse anthropogenic disturbances that may be sources of acute and chronic stress. Quantification of glucocorticoid (GC) concentrations has repeatedly been used to explore the impact of disturbances on physiological stress. Although it is still debated, prolonged elevation of GC levels may impair reproduction, growth, and immune system activity of individuals. We quantified the effect of anthropogenic disturbances on physiological stress in primates with a global meta-analysis based on data from 26 articles, covering 24 distinct species in 13 different countries. Anthropogenic disturbances were classified into 6 distinct categories: habitat loss, habitat degradation, ongoing logging, hunting, tourism, and other human activities. We calculated effect sizes (Hedges' g) with the standardized mean difference in GC concentrations between primates affected by human activity and their undisturbed conspecifics. We ran random-effects models and subgroup analyses to estimate the overall effect as well as a cumulative effect size for each disturbance category. Overall, primates inhabiting sites subject to anthropogenic disturbances exhibited significantly higher GC levels (g = 0.60; 95% CI: 0.28-0.93). Habitat loss and hunting were overall associated with increased GC concentrations, whereas the cumulative effects of the other disturbances were not statistically significant. Biologically, high GC levels may increase fitness by enabling individuals to overcome the challenges linked to anthropogenic disturbances. However, primates in disturbed environments may have sustained elevated GC levels. To strengthen future research, it is necessary to control confounding factors systematically (e.g., diet, reproductive status, predatory pressure, and resource availability) and improve understanding of the link between GC levels and the health, fitness, and survival of animals.