Effects of Anthropogenic Disturbance on the Biophysical Features of a Tropical Inland Valley Wetland

The changes in soil organic carbon (C) mineralization as affected by anthropogenic disturbance directly determine the role of soils as C source or sink in the global C budget. The objectives of this study were to investigate the effects of anthropogenic disturbance (aquaculture pond, pollutant discharge and agricultural activity) on soil organic C mineralization under different water conditions in the Minjiang River estuary wetland, Southeast China. The results showed that the organic C mineralization in the wetland soils was significantly affected by human disturbance and water conditions (P aquaculture pond sediment > soil near the discharge outlet > rice paddy soil. This indicated that human disturbance inhibited the mineralization of C in soils of the Minjiang River estuary wetland, and the inhibition increased with the intensity of human disturbance. The data for cumulative mineralized CO2-C showed a good fit (R2 > 0.91) to the first-order kinetic model C t = C0 (1–exp(–kt)). The kinetic parameters C0, k and C0k were significantly affected by human disturbance and water conditions. In addition, the total amount of mineralized C (in 49 d) was positively related to C0, C0k and electrical conductivity of soils. These findings indicated that anthropogenic disturbance suppressed the organic C mineralization potential in subtropical coastal wetland soils, and changes of water pattern as affected by human activities in the future would have a strong influence on C cycling in the subtropical estuarine wetlands.

The role of chronic anthropogenic disturbances in plant community assembly along a water availability gradient in Brazil’s semiarid Caatinga region

Understanding the processes that shape biological communities under a variety of perturbations is a central challenge in ecology and conservation. Mammals contribute to critical functional processes of an ecosystem, such as seed dispersal to maintain forest carbon stocks. The analysis of functional diversity, which measures the range and value of the ecological traits of organisms, provides critical information to understanding the link between biodiversity and ecosystem functioning. A growing number of studies have investigated the effects of anthropogenic disturbances on mammalian functional diversity; however, their results are very heterogeneous. Here, we conduct a comprehensive meta‐analysis of the effects of such anthropogenic disturbances on mammalian functional diversity in the tropics. We highlight major trends and analyse the influence of the type of anthropogenic disturbance, subgroups, and the functional diversity index used/applied. Our results indicate a negative effect of anthropogenic disturbances on mammalian functional diversity, particularly on functional richness (FRic) and functional dispersion (FDis). Habitat isolation was the stressor with the strongest effect, while agriculture and urbanisation showed a positive link with functional diversity. These results indicate that anthropogenic disturbances not only affect taxonomic diversity, but also reduce the functional diversity of mammals, which is likely to affect ecosystem functioning and possibly ecosystem service provision.

Effects of anthropogenic disturbances on diaspore removal by ants: A meta-analysis

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.

Associations of anthropogenic activity and disturbance with fitness metrics of eastern bluebirds ( Sialia sialis)

Anthropogenic activities have led to the biotic homogenization of many ecological communities, yet in coastal systems this phenomenon remains understudied. In particular, activities that locally affect marine habitat-forming foundation species may perturb habitat and promote species with generalist, opportunistic traits, in turn affecting spatial patterns of biodiversity. Here, we quantified fish diversity in seagrass communities across 89 sites spanning 6° latitude along the Pacific coast of Canada, to test the hypothesis that anthropogenic disturbances homogenize (i.e., lower beta-diversity) assemblages within coastal ecosystems. We test for patterns of biotic homogenization at sites within different anthropogenic disturbance categories (low, medium, and high) at two spatial scales (within and across regions) using both abundance- and incidence-based beta-diversity metrics. Our models provide clear evidence that fish communities in high anthropogenic disturbance seagrass areas are homogenized relative to those in low disturbance areas. These results were consistent across within-region comparisons using abundance- and incidence-based measures of beta-diversity, and in across-region comparisons using incidence-based measures. Physical and biotic characteristics of seagrass meadows also influenced fish beta-diversity. Biotic habitat characteristics including seagrass biomass and shoot density were more differentiated among high disturbance sites, potentially indicative of a perturbed environment. Indicator species and trait analyses revealed fishes associated with low disturbance sites had characteristics including stenotopy, lower swimming ability, and egg guarding behavior. Our study is the first to show biotic homogenization of fishes across seagrass meadows within areas of relatively high human impact. These results support the importance of targeting conservation efforts in low anthropogenic disturbance areas across land- and seascapes, as well as managing anthropogenic impacts in high activity areas.

Diatom assemblages attached to the leaves of the submerged macrophyte Vallisneria aethiopica in the shallow waters of the Sanyati Basin in Lake Kariba were analysed to assess their response to human impact. Human activities occurring within approximately 500 m of the shoreline were assessed at ten sampling sites along the shores of the basin. Eleven human activity factors were assessed and scored on a scale of 0 (not occurring at the site), 1 (low), 2 (medium) and 3 (high). Based on these 11 factors, we obtained a total score for the sites, which were then categorized as either having no human disturbance (0), low human disturbance (1–11), medium human disturbance (12–22) or high levels of human disturbance (23–33). Three sites were categorized as having no human disturbance, one had low disturbance and six had medium level human disturbance. A total of 9993 diatoms belonging to 40 genera were identified. The most abundant genera were Achnanthidium and Gomphonema, which made up 23.4 and 42.9% of the total diatom count, respectively. Achnanthidium dominated in remote areas with minimal human activities, while Gomphonema was more abundant in areas adjacent to increased human activities. The relative abundances of Achnanthidium, Denticula, Pinnularia, Rhopalodia and Stauroneis were negatively and significantly correlated, while that of Gomphonema was positively and significantly correlated to the human disturbance score (Spearman correlation, P 0.05), the lowest levels of these descriptors of community assemblage occurred at sites located near areas with relatively high human activities. The abundances of Achnanthes, Cymbella, Denticula, Encyonema and Pinnularia, Bacillaria and Mastogloia, Diatoma and Navicula and Eunotia and Mastogloia significantly decreased with increasing levels of total phosphorous, nitrate–nitrogen (N), ammonium–N and water turbidity, respectively (Spearman correlation, P < 0.05). Of the16 diatom index of biotic integrity (DIBI) metrics, 11 were significantly correlated with at least one of the environmental variables, while nine metrics were significantly correlated with the composite DIBI. Among the environmental variables the disturbance score was the only one that was significantly correlated with the DIBI. We conclude that although there is need for further work, periphytic diatoms associated with V. aethiopica may potentially be useful in assessing ecological conditions or the impact of human activities within the shallow marginal waters of Lake Kariba.

&#x0D; &#x0D; &#x0D; Population viability analysis (PVA) allows assessing extinction risk, which is of paramount importance for conservation and natural resource management practices. In addition to the modeling of the influence of deterministic demographic processes on the extinction risk of populations, PVA allows simulating the consequences of stochastic factors. The aim of the present study was to model the potential effects of two stochastic sources of variation, anthropogenic disturbance events (ADE) and hurricanes, on demographic parameters of extinction risk for 11 populations of the Endangered black howler monkey, in Campeche, Mexico. Models were built using information collected during a seven-year demographic monitoring of the populations, as well as on published life history data. We used the software VORTEX to study four extinction parameters: population growth rate; final population size; probability of extinction; years to extinction. For each population we ran five models: a baseline model; one model with 5% increase in the frequency of ADE; one model with 10% increase in ADE; one model with 5% increase in hurricanes; one model with 10% increase in hurricanes. We ran a sixth model excluding ADE for populations that were known to be exposed to ADE in baseline models. Hurricanes did not impact extinction parameters. As ADE increased, population growth rate, final population size, and years to extinction decreased, whereas probabilities of extinction increased. When ADE was removed, population growth decreased more slowly, populations included more indi- viduals, and extinction became less probable and was delayed. Small populations that were not affected by ADE faced high extinction risk. ADE is thus predicted to be a major stochastic factor influencing the extinction risk of black howler monkeys in Campeche, although population size is also determinant for long-term viability. Through PVA based on long-term demographic data, this study is the first to ascertain that decreasing anthropogenic disturbance may benefit the persistence of threatened populations of this species.&#x0D; &#x0D; &#x0D;

Effects of anthropogenic disturbances on bird functional diversity: A global meta-analysis

Long-distance migration by terrestrial mammals is a phenomenon critical to the persistence of populations, but such migrations are declining globally because of over-harvest, habitat loss, and movement barriers. Increasingly, there is a need to improve existing routes, mitigate route segments affected by anthropogenic disturbance, and in some instances, determine whether alternative routes are available. Using a hypothesis-driven approach, we identified landscape features associated with the primary functional attributes, stopovers and movement corridors, of spring migratory routes for mule deer in two study areas using resource selection functions. Patterns of selection for landscape attributes of movement corridors and stopovers mostly were similar; however, landscape features associated with movement corridors aligned better with areas that facilitated movement, whereas selection of stopovers was consistent with sites offering early access to spring forage. For movement corridors, deer selected for dry sites, low elevation, and low anthropogenic disturbance. For stopovers, deer selected for dry sites, with consistently early green-up across years, south-southwesterly aspects, low elevation, and low anthropogenic disturbance. Stopovers and movement corridors of a migratory route presumably promote different functions, but for a terrestrial migrant, patterns of habitat selection indicate that the same general habitat attributes may facilitate both movement and foraging in spring. Our findings emphasize the roles of topographical wetness, vegetation phenology, and anthropogenic disturbance in shaping use of the landscape during migration for this large herbivore. Avoiding human disturbance and tracking ephemeral forage resources appear to be a consistent pattern during migration, which reinforces the notion that movement during migration has a nutritional underpinning and disturbance potentially alters the net benefits of migration.

Objectives: Terrestrial ecosystems depend on forests for various services and functions, which are vital to biodiversity. The study examines anthropogenic impacts on soil quality caused due to anthropogenic disturbance. Methods: Three research sites (undisturbed, moderately disturbed, and highly disturbed forest stands) were selected, based on the degree of disturbance considering the canopy cover. Soil samples were collected from two depths i.e., 0-10 cm (topsoil) and 10-20 cm (subsoil) depths on the seasonal basis (pre-monsoon, monsoon, and post-monsoon seasons) and analysed for various characteristics namely, bulk density, pH, organic carbon content, moisture content, and nutrient availability (potassium, phosphorus, and nitrogen). Findings: With a range of 17.44 ± 0.52% to 44.13 ± 0.48%, the results showed an inverse relationship between the degree of disturbance and soil moisture. Soil bulk density values ranging from 0.71 ± 0.11 g/cm3 to 1.36 ± 0.01 g/cm3 and soil compaction increased with disturbance. The less disturbed site had a greater acidic level, with pH range of 4.59 ± 0.06 to 5.88 ± 0.03. Higher concentrations in topsoil showed a substantial variation in the organic carbon content (0.92 ± 0.03%-3.66 ± 0.19%). In contrast to disturbed stands, undisturbed stands have significantly better nutrient availability. The results demonstrate how anthropogenic disturbance impairs soil health. Novelty: Unlike many studies which focus on general forest degradation, the present study shows how anthropogenic activities like jhum cultivation and unsustainable logging have affected the soil health of Mizoram’s forests along various degree of disturbance. It also highlights how seasonal variation affects soil health. The study shows the importance of implementing sustainable forest management practices to prevent soil degradation. Keywords: Anthropogenic disturbance; Forest; Soil nutrient; Seasonal variation; Soil depth

Anthropogenic disturbances pose significant threats to biodiversity. However, limited information has been acquired regarding the degree of impact human disturbance has on the β-diversity of plant assemblages, especially in threatened ecosystems (e.g., floodplains). In the present study, the effects of anthropogenic disturbance on plant communities of floodplain areas (the Miya River, Mie Prefecture, Japan) were analyzed. The taxonomic and functional β-diversity among different degradation levels were compared, and the differences were assessed by tests for homogeneity in multivariate dispersions. In addition, the effects of non-native species and environmental factors on β-diversity were analyzed. As revealed from the results, anthropogenic disturbance led to taxonomic homogenization at a regional scale. The increase in non-native invasions tended to improve homogenization, whereas at a low degradation level, the occurrence of non-natives species was usually related to taxonomic differentiation. Furthermore, though the increase in non-natives and environmental parameters significantly affected the β-diversity of the floodplain area, environmental factors may be of more crucial importance than biotic interactions in shaping species assemblages in this study. The previously mentioned result is likely to be dependent on the research scale and the extent to which floodplains are disturbed. Given the significant importance of floodplains, the significance of looking at floodplains in the different levels of degradation was highlighted, and both invasion of non-native species and environmental factors should be considered to gain insights into the response of ecosystems to anthropogenic disturbance. The findings of this study suggested that conservation programs in floodplain areas should place more emphasis on the preservation of natural processes and forest resources.

Anthropogenic habitat disturbance impairs ecosystem health by fragmenting forested areas, introducing environmental contamination, and reducing the quality of habitat resources. The effect of this disturbance on wildlife health is of particular concern in Madagascar, one of the world's biodiversity hotspots, where anthropogenic pressures on the environment remain high. Despite the conservation importance of threatened lemur populations in Madagascar, few data exist on the effects of anthropogenic disturbance on lemur health. To examine these impacts, indri (Indri indri) populations were evaluated from two forest reserves that differ in their exposure to anthropogenic disturbance. We compared the health status of 36 indri individuals from two sites: one population from a protected, undisturbed area of lowland evergreen humid forest and the other population from a reserve exposed to frequent tourism and forest degradation. Comparison of indri health parameters between sites suggests an impact of anthropogenic disturbance, including significant differences in leukocyte count and differential, 12 serum parameters, 6 trace minerals, and a higher diversity of parasites, with a significant difference in the presence of the louse, Trichophilopterus babakotophilus. These data suggest that indri living in disturbed forests may experience physiological changes and increased susceptibility to parasitism, which may ultimately impair reproductive success and survival.

Environmental conditions, including anthropogenic disturbance, can significantly alter host and parasite communities. Yet, our current knowledge is based mainly on endoparasites, while ectoparasites remain little studied. We studied the indirect effects of anthropogenic disturbance (human population density) and climate (temperature, precipitation and elevation) on abundance of highly host-specific bat flies in four Neotropical bat species across 43 localities in Venezuela. We formulated a set of 11 a priori hypotheses that included a combination of the two effectors and host species. Statistically, each of these hypotheses was represented by a zero-inflated negative binomial mixture model, allowing us to control for excess zeros in the data. The best model was selected using Akaike's information criteria. Fly abundance was affected by anthropogenic disturbance in Artibeus planirostris, Carollia perspicillata and Pteronotus parnellii, but not Desmodus rotundus. Climate affected fly abundance in all bat species, suggesting mediation of these effects via the host or by direct effects on flies. We conclude that human disturbance may play a role in shaping bat-bat fly interactions. Different processes could determine fly abundance in the different bat species.