Impact Of Anthropogenic Disturbance Research Articles

Linking fungal dynamics, tree growth and forest management in a Mediterranean pine ecosystem

Fungal dynamics are a key component of forest ecosystem functioning. Understanding the links between stand dynamics and mushroom productivity together with the impact of anthropogenic disturbance (i.e., forest management) is necessary to provide further insight into plant-soil interactions in forest ecosystems. The aim of this research was to shed light on the relationship between tree growth and mushroom yield of ectomycorrhizal (ECM) and saprobic fungi in a Mediterranean forest ecosystem. We hypothesized that: (i) increased tree growth is linked to higher ECM mushroom yield arising from increased carbohydrate allocation to ECM fungi; (ii) saprobic mushroom yield is less dependent on tree growth patterns; and (iii) mushroom yields can be predicted based on certain wood-anatomical features. The study area was a Mediterranean Pinus pinaster forest located in northeastern Spain. Mushroom yield data were measured from 2008 to 2014 in 27 permanent plots within a thinning experiment. Dendrochronological analyses were conducted in each plot to characterize and quantify seasonal radial growth (earlywood and latewood width) and the frequency of latewood intra-annual density fluctuations (IADFs). Spearman correlation and “Gleichläufigkeit” (GLK) analyses were conducted to detect significant correlations and to quantify the synchrony between tree-ring features and ECM and saprobic mushroom yield patterns, the latter being used as a benchmark to better assess the relationships between tree growth and ECM fungi. To further inspect tree growth-mushroom yield relationships, mixed-effects models using dendrochronological variables as predictors were fitted to annual ECM and saprobic mushroom occurrence and yield data. We observed that the latewood IADFs frequency was the best predictor of ECM mushroom yield, i.e., better than early- or latewood width. The analysis also revealed that not only the precipitation of late summer and early autumn, but also forest thinning effects, were mediating the relationship between tree growth and ECM mushroom production. We found 2-year lagged effects between the current saprobic mushroom production and latewood width, whereas ECM mushroom yield was more correlated with current latewood production. The models presented in this study may be used to reconstruct mushroom production along historical periods based on dendrochronological information, but also to predict future mushroom yield based on climate-sensitive tree and stand growth predictions.

Low signal-to-noise FDEM in-phase data: Practical potential for magnetic susceptibility modelling

In this paper, we consider the use of land-based frequency-domain electromagnetics (FDEM) for magnetic susceptibility modelling. FDEM data comprises both out-of-phase and in-phase components, which can be related to the electrical conductivity and magnetic susceptibility of the subsurface. Though applying the FDEM method to obtain information on the subsurface conductivity is well established in various domains (e.g. through the low induction number approximation of subsurface apparent conductivity), the potential for susceptibility mapping is often overlooked. Especially given a subsurface with a low magnetite and maghemite content (e.g. most sedimentary environments), it is generally assumed that susceptibility is negligible. Nonetheless, the heterogeneity of the near surface and the impact of anthropogenic disturbances on the soil can cause sufficient variation in susceptibility for it to be detectable in a repeatable way. Unfortunately, it can be challenging to study the potential for susceptibility mapping due to systematic errors, an often poor low signal-to-noise ratio, and the intricacy of correlating in-phase responses with subsurface susceptibility and conductivity. Alongside use of an accurate forward model – accounting for out-of-phase/in-phase coupling – any attempt at relating the in-phase response with subsurface susceptibility requires overcoming instrument-specific limitations that burden the real-world application of FDEM susceptibility mapping. Firstly, the often erratic and drift-sensitive nature of in-phase responses calls for relative data levelling. In addition, a correction for absolute levelling offsets may be equally necessary: ancillary (subsurface) susceptibility data can be used to assess the importance of absolute in-phase calibration though hereby accurate in-situ data is required. To allow assessing the (importance of) in-phase calibration alongside the potential of FDEM data for susceptibility modelling, we consider an experimental test case whereby the in-phase responses of a multi-receiver FDEM instrument are calibrated through downhole susceptibility data. Our results show that, while it is possible to derive approximate susceptibility profiles from FDEM data, robust quantitative analysis hinges on appropriate calibration of the responses.

Fine-scale movement responses of free-ranging harbour porpoises to capture, tagging and short-term noise pulses from a single airgun.

Knowledge about the impact of anthropogenic disturbances on the behavioural responses of cetaceans is constrained by lack of data on fine-scale movements of individuals. We equipped five free-ranging harbour porpoises (Phocoena phocoena) with high-resolution location and dive loggers and exposed them to a single 10 inch3 underwater airgun producing high-intensity noise pulses (2–3 s intervals) for 1 min. All five porpoises responded to capture and tagging with longer, faster and more directed movements as well as with shorter, shallower, less wiggly dives immediately after release, with natural behaviour resumed in less than or equal to 24 h. When we exposed porpoises to airgun pulses at ranges of 420–690 m with noise level estimates of 135–147 dB re 1 µPa2s (sound exposure level), one individual displayed rapid and directed movements away from the exposure site and two individuals used shorter and shallower dives compared to natural behaviour immediately after exposure. Noise-induced movement typically lasted for less than or equal to 8 h with an additional 24 h recovery period until natural behaviour was resumed. The remaining individuals did not show any quantifiable responses to the noise exposure. Changes in natural behaviour following anthropogenic disturbances may reduce feeding opportunities, and evaluating potential population-level consequences should be a priority research area.

Impacts of anthropogenic disturbances on forest succession in the mid-montane forests of Central Himalaya

We studied the influence of anthropogenic drivers on the distribution and regeneration of tree species in vegetation at different stages of succession from grasslands to oak forests in mid-montane Central Himalaya. We found fire, grazing, and lopping as the main factors hindering a progressive successional regime towards a late-successional oak community. Succession was studied in five vegetation formations (grasslands, pine, pine–oak, open oak, and dense oak), with similar site conditions, representing a theoretical successional sequence from early- to late-successional stages. A structured survey with uniform distribution of sampling plots in the five selected vegetation formations was conducted to gather information abut the vegetation communities. Early-successional grasslands and pine forests were found to harbour high densities of pine and oak seedling and sapling regeneration. However, recurring fires and chronic unsustainable levels of grazing in these vegetation formations obstructed progressive succession by eliminating regenerating seedling and saplings from the forest understorey. Similarly, in intermediate- and late-successional stages (including pine–oak, open oak, and dense oak), overexploitation of existing oaks trees via lopping and grazing of regenerating oak seedlings and saplings hampered oak regeneration and development. The possibility to convert pine forests into oak as well as the conservation of existing oak forests through controlled grazing and lopping are management options that can contribute to an enhanced functioning of forest ecosystems in the study area. We conclude that with strategic management that restricts the current anthropogenic disturbances, the extent of oak forest in the study area can be increased.

The effects of anthropogenic disturbances and hydrological activity of a river on soil Collembola communities in an urbanized zone

Soil Collembola communities inhabiting urban zones are highly modified by anthropogenic disturbances. This effect has not yet been studied along an urban river, where hydrological processes play an important role. The main objective of the present study was to test the hypothesis that the impact of anthropogenic disturbances on the variation in Collembola communities is distinctly different in the riparian area of a river and in nearby area not influenced by processes associated with river activity, i.e. exposed only to urbanization. The study was performed in Warsaw and surroundings (Poland) along the Vistula River. Sampling was conducted in three locations, varying with respect to the level of anthropogenic disturbances – in the city center (high level of anthropogenic disturbances), at the edge of city (moderate level of anthropogenic disturbances) and outside of the city (low level of anthropogenic disturbances), each in the area located in front of the levee (prevalent influence of hydrological processes) and behind the levee (lack of river influence), in spring and autumn. The level of anthropogenic disturbances was associated with a significant variation in the Collembola communities only in the area located behind the levee. Season was associated with significant community variation only in the area located in front of the levee, which can be induced by variable hydrological processes. It can be concluded that anthropogenic disturbances do not affect Collembola communities in the riparian area of an urban river, which reflects the high resistance of communities associated with inundated soils to disturbances in a city.

Impact of anthropogenic disturbances on a diverse riverine fish assemblage in Fiji predicted by functional traits

Abstract Anthropogenic disturbances particularly affect biodiversity in sensitive freshwater ecosystems by causing species loss. Thus, measuring the response of species to multiple disturbances is a key issue for conservation and environmental management. As it is not practical to assess the response of every species in a community, we compared the performance of trait and taxonomic‐based groupings of species for their abilities to predict species loss in a threatened freshwater fish assemblage. Specifically, we examined responses of a Fijian freshwater fish assemblage to deforestation, placement of anthropogenic barriers (overhanging culverts) and the presence of introduced cichlids. Species grouped by traits showed more consistent responses to disturbances than taxonomic groups. In particular, species belonging to trait groups that were estuary associated favoured medium‐to‐hard substrate, while feeding specialists were highly likely to be absent in catchments with high deforestation and overhanging culverts. The presence of introduced cichlids (Oreochromis mossambicus and O. niloticus) had a smaller effect than deforestation and barriers, but was negatively associated with species richness of diadromous species with climbing ability and positively associated with presences of some piscivores. The trait groups also revealed that detritivores, species favouring soft substrate, and those with a broad dietary range were less sensitive to anthropogenic disturbances. Our study indicates that using traits to predict species loss from disturbed environments can aid in detecting the responses of rare species to disturbance. In addition, we provided a method to estimate the consistency of species’ responses to disturbance. This study may ultimately help managers identify the most effective actions for conserving sensitive species that are seldom recorded in surveys.

Impact of anthropogenic disturbance on the chemistry of a small urban pond

Mirror Lake, one of the scenic locations on The Ohio State University's campus, experiences an intense bioturbation event as part of an annual tradition revolving around the rivalry football game against the University of Michigan. This tradition involves thousands of students jumping into the lake over one night in the week leading up to the football game.Water samples were collected from several locations in the lake before, during, and after the Mirror Lake Jump to determine the impact of this event on lake water chemistry. There were significant and systematic increases in the concentrations of Na+, K+, Cl−, total nitrogen, ammonia, and dissolved organic carbon (DOC) associated with the jump, especially in the eastern side of the lake where most of the students entered. Over the 3-h period from 10 p.m. to 1 a.m. on the eastern side of the lake, Na+, K+, and Cl− concentrations increased by about 2–4 ppm, 1.5–3 ppm, and 4–6 ppm, respectively. The total nitrogen concentration increased about five to six fold, from 450–500 ppb to 2300–2800 ppb over the height of the event on the eastern side of the lake. Similar increases were observed for DOC, increasing from 3.6 to 18 ppm. This DOC increase was coincident with a 5‰ shift in δ13C, from a mean of around −28‰ in the early hours of the evening to a maximum of −23‰, implying a large influx of isotopically heavy carbon into the lake. Ammonia concentrations varied substantially from year to year, but always showed a systematic increase in concentration during the event. Smaller changes in major ion and nutrient concentrations were observed in the middle and western side of the lake, where fewer students entered the lake.The changes in concentration and the timing and spatial distribution of these changes are primarily attributed to anthropogenic input from jumpers in the form of bodily fluids (e.g., evaporated sweat, sebum and urine). Over a single night, these anthropogenic event inputs represent roughly 10% of the annual nitrogen budget of the lake, emphasizing the direct impact humans can have on urban water bodies on short time scales.

Impact of Anthropogenic Disturbances on Ecology of Pinus gerardiana Wall in Indian Himalaya: A Review

: Chilgoza pine (Pinus gerardiana Wall.) has a restricted distribution in India, though it is an important ecological and economic species in the Himalaya. This species is restricted in dry temperate region of North-Western Himalaya but lack of regeneration has threatened species existence in the Himalaya. Because, large numbers of biotic and abiotic factors have affected P. gerardiana in these forests; hence, there is a crucial need to review ecological status of species in the region. One of the important site factor is the collection of cone/seed by local villagers from most of the trees, while few trees those grows in remote areas and steep slopes, which cannot be harvested, only provide seeds for the regeneration. Young trees are scarce or entirely lacking, the mature trees predominate in its natural zone. Phytosociological study showed the high endemism of the Pinus gerardiana in its natural zone. Overall more than 70% of the area was covered by this species and rest by other species. Therefore, the productivity and sustainability of chilgoza pine need to be ensured.

The Impact of Anthropogenic Disturbance on Assembly Patterns of Termite Communities

AbstractIntensification of land‐use threatens biodiversity, especially in tropical ecosystems that harbor the planet's highest species richness. This negative impact of anthropogenic disturbance on species numbers is well established, but the mechanisms underlying the community assembly processes are less well understood. Termites are of fundamental importance in tropical ecosystems where they are critical for nutrient recycling and species diversity. We tested the impact of anthropogenic disturbance on termite species diversity and assembly processes in a West African savanna applying the newest techniques of phylogenetic community analyses. Species richness dropped in areas of intensive land‐use and compositional similarity between intensive land‐use areas was high. This contrasted with a protected National Park where communities were characterized by high species richness and intermediate species turnover between sites. Slightly disturbed areas in the buffer zone surrounding the park were intermediate, they still had high species richness but similarity between sites increased. Strikingly, the assembly pattern also changed with disturbance from more phylogenetic overdispersion to more clustering (coexisting species became phylogenetically more similar), but only when the fungus‐growing termite Macrotermes bellicosus was absent. Our data suggest that the major forces structuring termite communities depend: (1) on the presence of this dominant mound‐building termite; and (2) that they change to more environmental filtering with disturbance. Anthropogenic disturbance seems to function as a filter that allows only a specific subset of species to occur. Such an effect might be widespread in ecology but it is difficult to document quantitatively. Phylogenetic community analyses can help to contribute such evidence.

Impact of anthropogenic disturbance on the density and activity pattern of deer evaluated with respect to spatial scale-dependency

This study examined the influence of anthropogenic disturbance (agriculture, forestry, hunting and feral domestic dogs) on the population density and daily activity pattern of deer. We quantified the effects of land use (broad-leaved forest, mixed coniferous/broad-leaved forest, natural grassland, subalpine vegetation, forestry area, and agricultural land), along with hunting pressure, and densities of feral domestic dogs and wild macaques on deer. The effects of land use were analyzed at various spatial scales and a model selection procedure (generalized mixed model) was used to examine the effects of factors on density and daily activity pattern of deer at each spatial scale. The combinations of influential factors differed between density and daily activity pattern and changed with spatial scale. The spatial scale with the smallest Akaike's Information Criterion value was defined as the effective spatial scale for each of density and daily activity pattern. Deer density was affected positively by the percentage of area covered by broad-leaved forest, natural grassland and macaque density, and negatively by percentage of area covered by agricultural land and mixed forest at the effective spatial scales. For the daily activity pattern of deer, agricultural land, forestry area, natural grassland, subalpine vegetation and dog density reduced diurnal and increased nocturnal activity. Crepuscular activity increased with hunting pressure and subalpine vegetation, and decreased with agricultural land. Thus, daily activity pattern was sensitive to more types of anthropogenic disturbance than density. Detecting the appropriate spatial scales at which significant anthropogenic disturbance should be managed is essential for effective wildlife conservation.

Shifts in landslide frequency–area distribution after forest conversion in the tropical Andes

The impact of anthropogenic disturbance on landslide occurrence has been clearly demonstrated for several case-studies worldwide. Deforestation has been identified as the main trigger for landslide activity. These studies are mainly based on landslide inventories from aerial photographs or remote sensing data, and often focus solely on the total number of landslides. Looking at the total number of landslides alone does not allow us to get a comprehensive insight into the overall anthropogenic impact on landslide denudation. In this study, we analysed the anthropogenic impact on landslide frequency-area distributions. Three small catchments of about 11-30 km2 were selected within the Ecuadorian Andes. They have a similar topographic setting but differ in their land cover dynamic. Our data show that human disturbances significantly alter the landslide frequency-area distributions. Human-induced land cover change is associated with an increase of the total number of landslides and a shift of the frequency-area distribution towards smaller landslides. However, the frequency of large landslides is not affected by anthropogenic disturbances. When analysing the geomorphic work realised by landslides in different environments, it becomes clear that the majority of landslide-induced sediment is coming from anthropogenic environments. The strong increase in the frequency of small landslides in anthropogenic environments thus plays an important role in enhancing the overall landslide denudation rate in tropical mountain regions.

Impacts of anthropogenic disturbances at deep-sea hydrothermal vent ecosystems: A review

Deep-sea hydrothermal-vent ecosystems have stimulated decades of scientific research and hold promise of mineral and genetic resources that also serve societal needs. Some endemic taxa thrive only in vent environments, and vent-associated organisms are adapted to a variety of natural disturbances, from tidal variations to earthquakes and volcanic eruptions. In this paper, physicochemical and biological impacts of a range of human activities at vents are considered. Mining is currently the only anthropogenic activity projected to have a major impact on vent ecosystems, albeit at a local scale, based on our current understanding of ecological responses to disturbance. Natural recovery from a single mining event depends on immigration and larval recruitment and colonization; understanding processes and dynamics influencing life-history stages may be a key to effective minimization and mitigation of mining impacts. Cumulative impacts on benthic communities of several mining projects in a single region, without proper management, include possible species extinctions and shifts in community structure and function.

人为干扰对乌海市四合木小灌木景观的影响

人为干扰对乌海市四合木小灌木景观的影响

RETRACTED: Impact of anthropogenic disturbance on the density and activity pattern of deer evaluated with respect to spatial scale-dependency

RETRACTED: Impact of anthropogenic disturbance on the density and activity pattern of deer evaluated with respect to spatial scale-dependency

Impact of Anthropogenic Disturbances on Methanotrophs Abundance in Dry Tropical Forest Ecosystems, India

Impact of Anthropogenic Disturbances on Methanotrophs Abundance in Dry Tropical Forest Ecosystems, India Dry tropical forest soil contributes the highest methane (CH4) consumption rates on a global scale. Methane oxidation in soils is mostly accomplished by methanotrophic bacteria (MB). Several workers have demonstrated that the anthropogenic activity on natural forests disturbs the CH4 sink attribute of the soil. However, there is no information concerning the impact of anthropogenic disturbances in dry tropical forests for soil methanotrophs densitydynamics. Impact of soil differences in different forest types (afforested and disturbed stands) on methanotrophs density was investigated in dry tropical region, India.

Avoidance of roads and selection for recent cutovers by threatened caribou: fitness-rewarding or maladaptive behaviour?

The impact of anthropogenic disturbance on the fitness of prey should depend on the relative effect of human activities on different trophic levels. This verification remains rare, however, especially for large animals. We investigated the functional link between habitat selection of female caribou (Rangifer tarandus) and the survival of their calves, a fitness correlate. This top-down controlled population of the threatened forest-dwelling caribou inhabits a managed forest occupied by wolves (Canis lupus) and black bears (Ursus americanus). Sixty-one per cent of calves died from bear predation within two months following their birth. Variation in habitat selection tactics among mothers resulted in different mortality risks for their calves. When calves occupied areas with few deciduous trees, they were more likely to die from predation if the local road density was high. Although caribou are typically associated with pristine forests, females selected recent cutovers without negative impact on calf survival. This selection became detrimental, however, as regeneration took place in harvested stands owing to increased bear predation. We demonstrate that human disturbance has asymmetrical consequences on the trophic levels of a food web involving multiple large mammals, which resulted in habitat selection tactics with a greater short-term fitness payoff and, therefore, with higher evolutionary opportunity.

Assessment and impact of anthropogenic disturbances in protected areas of northern Togo

These days, human activities in the savanna and the remaining dry and riparian forests of the Sudanian ecoregions continue to have their impact. These anthropogenic practices are still the main cause of disturbances in these areas. In order to investigate and assess the importance of these disturbances, caused by people bordering on protected areas and to determine the relation between these activities and the environment in which they are carried out, 220 samples were selected in the three main protected areas of northern Togo. The investigation was mainly qualitative, considering the floristic sampling of this drought area; any anthropogenic activities observed were recorded. A simple investigative questionnaire about the activities of rural people in the reserved areas was distributed to individuals encountered in the study area. Each sample in the investigation ended with a site description of its ecological characterization, i.e., soil features, topography, fauna footprints, dominant plant species and GPS position; we also took photographs of the site. Data processing was entirely based on descriptive statistics and a factor analysis. The results show that eight kinds of human activities, i.e., the use of pastures, tree cutting, bush fires, charcoal production, harvesting of plant material, farming, honey harvesting and hunting, were noted to be serious disturbances to the integrity of the ecosystems. Among these disturbances, three are recurrent in all the sampled areas of which the use of pastures accounts for 31.88%, tree cutting for 30.35% and bush fires for 30.13%. Fire and pasture disturbances are closely linked and are responsible for the current features of the savanna area of the region. Tree cutting is more a direct function of the need for the production of wood fuel, generally used by city populations. Hunting, farming and honey production are of lesser importance in the area and therefore, do not pose a significantly negative effect on the growth of fauna and flora. Knowledge of these disturbances in the context of requalification and a renewed demarcation of protected areas in Togo is essential for their sustainable management.

Modelling the responses of wildlife to human disturbance: An evaluation of alternative management scenarios for black-crowned night-herons

The impact of anthropogenic disturbance on wildlife is increasing becoming a source of concern as the popularity of outdoor recreation rises. There is now more pressure on site managers to simultaneously ensure the continued persistence of wildlife and provide recreational opportunities. Using ‘Simulation of Disturbance Activities’, a model designed to investigate the impact of recreational disturbance on wildlife, we demonstrate how a simulation modelling approach can effectively inform such management decisions. As an example, we explored the implications of various design and management options for a proposed recreational area containing a historic breeding bird colony. By manipulating the proximity, orientation and intensity of recreation, we were able to evaluate the impact of recreational activities on the behaviour of black-crowned night-heron nestlings ( Nycticorax nycticorax). Using a classification and regression tree (CART) procedure to analyse simulation output, we explored the dynamics of multiple strategies in concert. Our analysis revealed that there are inherent advantages in implementing multiple strategies as opposed to any single strategy. Nestlings were not disturbed by recreation when bird-watching facility placement (proximity and orientation) and type were considered in combination. In comparison, proximity alone only led to a <10% reduction in disturbance. Thus we demonstrate how simulation models based on customised empirical data can bridge the gap between field studies and active management, enabling users to test novel management scenarios that are otherwise logistically difficult. Furthermore, such models potentially have broad application in understanding human-wildlife interactions (e.g. exploring the implications of roads on wildlife, probability of bird strikes around airports, etc.). They therefore represent a valuable decision-making tool in the ecological design of urban infrastructures.

Impact of anthropogenic disturbances on the diversity of shallow stony corals in the Veracruz Reef System National Park

Anthropogenic disturbances may affect the development and maintenance of coral reefs by promoting diseases and other syndromes. In turn, this may cause local decreases in coral species diversity. In this study, we compared the prevalence of syndromes (including diseases and non-disease syndromes) and the diversity of stony coral species between reefs located close (Sacrificios reef) and far away (Santiaguillo reef) of the port of Veracruz, Mexico. The prevalence of syndromes was higher at Sacrificios than at Santiaguillo, and it also increased with the abundance of coral colonies at the former reef. On the other hand, coral diversity was lower at Sacrificios than at Santiaguillo, suggesting that anthropogenic disturbances, besides promoting diseases and other syndromes, also lead to local decreases in species diversity.

Preliminary Assessment of Anthropogenic Impact on Some Ecological Components of Abesan River, Lagos, Nigeria

The impact of anthropogenic disturbances on water quality parameters, diversity of macrophytes and benthic macro fauna of Abesan River, Lagos, Nigeria is reported. Some Physico-chemical and biological assessment were carried out at three sampling stations located at downstream (AR-1), midstream (AR-2) and upstream (AR-3) with different levels of disturbance. Results of measured physico-chemical parameters showed that there was no significant difference (P > 0.05) in temperature, total acidity and chloride values between the sampling stations. Although, Total solids, conductivity, DO, Sulphate, BOD and COD were significantly higher (P < 0.05) at Stn.AR-1 than at Stns. AR-2 and AR-3, all physico-chemical parameters measured were within the limits of the Lagos State Environmental Protection Agency (LASEPA) and the World Health Organization (WHO) regulatory standards except for high COD concentration in downstream station. Aquatic vegetation (macrophyte) diversity was relatively abundant at upstream and downstream stations, suggesting possible impact of human activities on macrophyte diversity at midstream station where highest level of disturbance occurred. Chironomid larvae were the most abundant invertebrate fauna found in all three sampling stations but more abundant at sampling station AR-2 which corresponds to point of effluent entry to river where human activities is most intense. There is evidence that anthropogenic activities impact on the water quality of Abesan River. Biotic indices such as Sorensenen’s Index of Similarity and Margalef Index show that Abesan River is lightly polluted. The implications of these results and the need to monitor the water quality of Abesan River are highlighted.