Effects Of Human Disturbance Research Articles

Dust emission from different land use types based on the PI-SWERL test

Dust emissions have important impacts on the ecological environment and air quality. To explore the underlying mechanisms, characteristics and influence factors of the dust emission from different land use types along the northern dust transport path of Beijing, a portable dust observation instrument (PI-SWERL) was used to test the dust emissions from typical land use types in both the leapfrog mode and progressive mode. The results showed that in the leapfrog mode, the dust emission concentrations (DECs) of the different land use types exhibited four patterns with increasing friction wind speed: fluctuation type, fluctuating growth type, linear growth type and growth stability type. In the progressive mode, the instantaneous dust emission fluxes (IDEFs) from the different land use types under the same friction wind speed exhibited three variation characteristics with increasing erosion time: rapid decline, decline after stabilization, and remaining stable. These variation characteristics preliminarily reflected the dust emission mechanisms and emission potentials of the different land use types. For different land types, the DEFs of grassland after crust destruction (GCD) and vineyard land (VL) were the largest, and the maximum value reached 14 mg/m2·s at a friction wind speed of 0.69 m/s. The DEFs of grassland (TS), stubble land (StL), saline-alkali land (SAL), shrubland (ShL) and grassland with crust (GC) were the lowest, with maximum DEFs of less than 0.3 mg/m2·s. The differences in dust emissions from different land types were mainly affected by the topsoil dust content, soil crust, surface vegetation and human disturbance. Under the influence of various factors, the DEFs of plowed land were 3.62–8.36 times greater than those of unplowed land and 81.78–175.50 times greater than those of grassland at friction wind speeds of 0.39, 0.55 and 0.69 m/s. The DEFs of land after removing stubble were 36.34–164.86 times greater than those of stubble land, and the DEFs of grassland after crust destruction were 50.50–195.25 times greater than those of grassland with crust. In this study, the PI-SWERL dust tests have important reference significance for analyzing dust emission mechanisms, characteristics, potential and effects of human disturbance in different land use types.

Ventilation strategy for particulate matter control in subway stations

Particulate matter severely affects human health, and its migration is closely related to human walking and ventilation. It is essential to select an appropriate ventilation strategy to control the particulate matter caused by cluster passengers walking. In this study, cluster passengers walk in the narrow passage of a subway station. Large eddy simulation (LES) was used to study the influence of cluster passengers walking on the transmission of particulate matter under ventilation conditions involving upper exhaust and lower exhaust. The risk of passengers exposure was analyzed by comparing the exposure levels of particulate matter at different heights under the effect of human disturbance. The results show that the amount of particulate matter near the legs is greatest during human walking. Clustered passengers disturbance airflow induces particulate matter to rise to the breathing zone, which increases the risk of human exposure. Lower-side exhaust conditions are more conducive to the discharge and control of particulate matter. The disturbance of cluster passengers enhances the continuous transmission of particulate matter in the wake flow. This study is applicable to traffic hubs and other public places where passengers gather, the ventilation of the upper side exhaust has better control effect on particulate matter caused by passengers wake flow.

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.

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.

Anthropogenic disturbances alter the trophic niche structure and ecological relationships of understory bat communities in the Ecuadorian Andean Chocó

Human disturbances have reduced the three basic niche dimensions for the survival of some mammalian species (space, time, and resources). Anthropic activities cause the extinction of ecological functionalities faster than species extinctions. In this study, we identified four types of habitats in the Ecuadorian Andean Chocó: primary forest (PF), secondary forest in natural regeneration (SF1), secondary forest in assisted regeneration (SF2), and pastures for cattle (P). The main objective was to determine the responses in the trophic niche and the ecological relationships of understory phyllostomid bat communities. We captured bats with mist nets and obtained fecal samples from 21 species. These were analyzed to quantify seeds, pollen, insects, and vertebrates consumed by each individual, with counts organized by species and habitat type. We conducted an ecological relationship analysis to understand the structure of bat–fruit networks and their dietary preferences. We calculated niche breadth and niche overlap to understand the trophic niche composition of each species. We applied null models to evaluate if there is evidence of trophic niche partitioning among these species. Despite a relatively small sample size, the results obtained are nevertheless interesting. While niche breadth was not useful for detecting the effects of human disturbances, niche overlap was significantly higher in disturbed habitats (SF1, SF2 and P), where ecological relationships were weaker. Most of the species were related to the consumption of seeds from the genus Piper. These results indicate that bat communities and their ecosystem services may be highly endangered due to anthropogenic disturbances. Network interactions in bats are highly variable in geographic space and time, and little is known about the community structure of bat–seed interactions. Studying mutualistic networks in bats and seeds is crucial because of their role in ecosystem support, supply, and regulation services that depend on them.

On the Conservation of the Canarian Laurel Forest: What Do Lichens Have to Say?

The fragmentation and degradation of primary forests are serious threats to the long-term persistence not only of the tree species they comprise, but also of many organisms inhabiting them. The Canarian laurel forest, known as monteverde, is a highly threatened endemic forest of the Macaronesian region. Lichens are considered ideal bioindicators for assessing the effects of human disturbances on ecosystems and anticipating the response of other less sensitive organisms. However, no studies have used them as model organisms to analyze the conservation status of this primary forest in the Macaronesian region. In the present study, we analyzed several variables of the lichen biota of the Canarian laurel forest on the islands with the highest representation within this archipelago: La Gomera, La Palma, and Tenerife. We analyzed the species richness (and its relationship to island size with the real and potential vegetation areas of the laurel forest); the lichen diversity value, the number of shared and exclusive species on each of the islands as well as lichen functional traits as they have become important for evaluating the response of epiphytic lichens to environmental changes. The results indicate that there are signs of a potential extinction debt occurring in the diversity of epiphytic lichens in some areas. Furthermore, it has been observed that, despite the presence of some exclusive species on each island, the overall composition does not differ between them. Considering the functional traits of lichens, there are patterns that can provide information about the unique characteristics of the laurel forest of each of the studied islands.

Impacts of visitors on female pheasants in pheasantry, Haripur, Pakistan.

The interaction between visitors and captive birds is complex, with a potential impact on bird's behavior and welfare. Understanding this interaction is essential for effective conservation and management. We conducted a study at the University of Haripur's pheasantry in Khyber Pakhtunkhwa, Pakistan to investigate the effects of visitor numbers, duration of visitor presence, and climatic factors on the behavior of female pheasants. We observed the state and events of feeding, hiding, and moving behaviors of 16 randomly selected individuals from five species. The mixed-effects modeling results show that visitors (VT), visitors' presence duration (VPD), and temperature (TP), significantly influence feeding events (p < 0.001), feeding duration (p < 0.001), hiding events (p < 0.001) and hiding duration of female pheasants (p < 0.001). The moving events of pheasants were also significantly affected by both VT and VPD (VT: p = 0.002, VPD: p < 0.001). Moreover, under high visitor conditions, the impact of VPD on the behavior of female pheasants was more pronounced (p < 0.001). Additionally, our result reveals that different species of pheasants exhibit varying sensitivities to human factors and climatic factors. For instance, the two species of female pheasants with the highest feeding and hiding events were the Green pheasant (Phasianus versicolor) and the Ring-necked pheasant (Phasianus colchicus). While hiding duration of female Green pheasants, female Golden pheasants (Chrysolophus pictus), and female Silver pheasants (Lophura nycthemera) was longer than those of others. The mean number of moving events was highest in females of Ring-necked, followed by Golden pheasants. The female Indian peafowl (Pavo cristatus) and female Silver pheasants were the birds with the longest moving duration. Our findings highlight the necessity for customized management strategies, to lessen the effects of human disturbances in pheasantries. For a thorough understanding of these interactions, more studies involving larger sample sizes and a wider variety of species are advised.

Elevation and Human Disturbance Interactively Influence the Patterns of Insect Diversity on the Southeastern Periphery of the Tibetan Plateau.

The maintenance of biodiversity and ecological balance heavily relies on the diversity of insects. In order to investigate the impacts of elevation and human disturbance, as well as their interactions on insect diversity, we conducted an intensive survey of insects in the Hengduan Mountain Range, which is situated on the southeastern periphery of the Tibetan Plateau in China. A total of 50 line transects were established in this study to investigate the impact of elevation and human disturbance on insect diversity and distribution patterns. Designed insect surveys were conducted at various elevations and levels of human disturbance, and statistical methods such as generalized linear modeling and redundancy analysis were employed for data analysis. The results of this study indicated a negative correlation between insect diversity and elevation. Additionally, moderate disturbance was found to have a positive impact on insect diversity to some extent. The explanatory power of the model for the distribution of insect diversity could be improved if elevation and human disturbance were included as an interaction effect into the model, and there were differences in the effects of human disturbances on insect diversity at different elevation levels. The highest insect diversity was observed under low disturbance conditions below elevation of ~2200 m, whereas above this threshold, insect diversity was the highest under moderate disturbance compared to low disturbance. The response of different insect taxa to the interactions of elevation and human disturbance varied. The findings imply that when formulating strategies for managing insect diversity, it is crucial to thoroughly consider the interaction of environmental factors and disturbance response of individual insect taxa.

A multi‐site and hypothesis‐driven approach to identify controls on the bedload transport regime of an anthropised gravel‐bed river

AbstractUnderstanding the effects of human disturbance on the bedload transport regime of anthropised rivers is a topic of growing importance, as such information is of interest for adequate river diagnosis, correct implementation of restoration measures and appropriate design of post‐action monitoring programs. However, such assessments are complex, especially in sites where multiple factors simultaneously influence the bedload transport regime, so that it is difficult to establish simple causal relationships between human disturbances and changes in the sediment transport regime, notably on bedload. To overcome this, there is a need for rigorous hypothesis‐driven approaches to assess the isolated effects of each driver. With this in mind, we have characterised the dynamics of bedload transport in the Upper Garonne (Central Pyrenees, Spain‐France), a river impacted by sediment retention, flow diversion and mining that influence its morphological conditions and transport regime. We assessed the effects of (1) surface grain size distribution, (2) river morphology, (3) sediment supply and (4) flow diversion on the bedload transport regime. Four sites with different degrees of river anthropisation were selected. After defining hypotheses on the most likely bedload transport conditions for each site, we proposed a set of discriminating criteria to test these hypotheses, based on temporal within‐site and spatial between‐site comparisons of coarse particle tracking measurements over four years. The results of this research showed that the hydrosedimentary regime of the Garonne is controlled by a complex combination of drivers such as valley physiography, which exerts a first‐order control on differences in reach‐scale bedforms and bedload dynamics; and human disturbances which contribute to a reduction in sediment supply through changes in land cover and hydropower dams, or to changes in hydrology (i.e., flow competence) due to water diversion and abstraction.

Mammal responses to human recreation depend on landscape context.

Rapid growth in outdoor recreation may have important and varied effects on terrestrial mammal communities. Few studies have investigated factors influencing variation in observed responses of multiple mammal species to recreation. We used data from 155 camera traps, in western Alberta (Canada), and a hierarchical Bayesian community modelling framework to document 15 mammal species responses to recreation, test for differential responses between predators and prey, and evaluate the influence of local context. Factors characterizing context were trail designation (i.e., use by motorized vs non-motorized), management type, forest cover, landscape disturbance, and season. We used three measures to characterize variation in recreation pressure: distance to trail, trail density, and an index of recreation intensity derived from the platform Strava. We found limited evidence for strong or consistent effects of recreation on mammal space use. However, mammal space use was better explained by an interaction between recreation and the influencing factors than by either on their own. The strongest interaction was between trail density and management type; mammals were more likely to avoid sites near a higher density of trails in areas with more restrictive management. We found that responses to recreation varied with the trail designation, although there were not clear or consistent differences between responses to trails designated for motorized vs. non-motorized use. Overall, we found that responses were species- and context-dependent. Limiting the density of trails may be important for reducing negative impacts to mammals within conservation areas. We show that using multiple measures of recreation yields more insight into the varied effects of human disturbances on wildlife. We recommend investigating how different characteristics of recreation (noise, speed, and visibility) influence animal behaviors. Multispecies monitoring and modelling across multiple landscapes that vary in recreation pressure can lead to an adaptive management approach to ensuring outdoor recreation coexistence with wildlife.

Conservation efforts mitigate effects of human disturbance on ghost crab (Ocypode macrocera) abundance and behavior on a sandy beach in Kuakata, Bangladesh

Protected areas play a crucial role in promoting and conserving species by providing a sanctuary for wildlife and natural habitats. In coastal regions, safeguarding measures become even more significant due to the unique challenges posed by anthropogenic activities. This study focuses on the impact of human activities on beach-dwelling biota, specifically the ghost crab (Ocypode macrocera), and highlights the importance of establishing protected areas to safeguard biodiversity and counteract negative impacts on coastal ecosystems. The study was conducted in Kuakata, the coastal region in Bangladesh, known for its ghost crab population. By comparing protected with non-protected beaches, the study examines the effects of protection status on ghost crab abundance and burrow characteristics. Field observations and data collection reveal that protected beaches harbor a greater abundance of ghost crabs compared to non-protected beaches. However, while protection status significantly improves crab abundance, it does not necessarily increase the mean burrow opening size. Interestingly, protected areas show a higher number of small burrow sizes, indicating that protected beaches not only act as feeding grounds but also serve as breeding and nursery grounds for ghost crabs. These findings illustrate the multifaceted role protected areas play in supporting the entire life cycle of ghost crabs, and underscore the importance of preserving these habitats for the species' long-term survival. It highlights the importance of effective management and conservation measures to preserve the health and integrity of coastal ecosystems. By establishing and managing protected areas appropriately, we can ensure the continued existence and viability of these invaluable habitats. Specific human activities that harm coastal biodiversity can be identified to develop targeted conservation strategies. Through this study, such strategies can be developed which may include measures like restricting beach access during breeding season or implementing sustainable tourism practices to lessen the impact.

The diversity, composition and functions of soil bacterial communities surrounding Syowa Station, East Antarctica, under different intensities of human disturbances

Since the establishment of Syowa Station over six decades ago, the study on the terrestrial bacterial community surrounding the station has been notably lacking and inadequately documented. Using the latest sequencing technology, we revealed the soil bacterial composition from soil samples collected from the surrounding of the station. In doing so, we also assessed the effect of human disturbances brought upon by different activities in the proximity of the station, in contrast to those in less human interference and pristine areas. Our results show that human activities near the main station facilities, especially within the 100-m range, visibly changed the structure and functions of the soil microbial community. Areas with high levels of human disturbances displayed a decrease in both microbial diversity and richness, accompanied by a lower count of unique amplicon sequence variants (ASVs) compared to regions with intermediate and low human disturbances. Moreover, higher proportions of functions related to hydrocarbon degradation were also predicted from samples collected within this area. In contrast, soil microbial communities from intermediate and low human disturbances samples have higher proportions of bacterial groups and functions consistent with those in undisturbed natural habitats.

The impact of anthropogenic disturbance and climate change on the distribution of Dekay’s brown snake (Storeria dekayi)

Abstract Human activities in the Anthropocene contribute to natural resource and climatic pattern shifts, which in turn affect the distributions of organisms. Currently, research efforts to understand organismal distribution patterns mainly focus on rare species, leaving common taxa to receive less attention. We constructed ecological niche models using MaxEnt to evaluate the distributions of a common urban reptile, Dekay’s brown snake (Storeria dekayi). We investigate the importance of human disturbance for the current S. dekayi distribution, the niche differentiation of the two genetic lineages of S. dekayi separated by the Mississippi River, and the potential future range shift of S. dekayi. We found no significant effect of human disturbance on current S. dekayi distribution. There was no significant evidence of niche differentiation between two lineages (eastern and western), which can possibly be attributed to their shallow genetic divergence. We also predicted a range expansion for S. dekayi in the future with anthropogenic climate change. Understanding the distribution patterns of common species is important because of the pivotal role they play in ecosystem functioning and services. We encourage more work to be conducted in the future on common and urban-dwelling species’ distributions to conserve and promote urban biodiversity and biodiversity overall.

Multi-taxon species richness representation within national nature reserves is associated with spatial features, human disturbance and environmental factors in mountains region

The Humboldt’s enigma has continued for many centuries, A multitude of studies have delved into various potential reasons for this richness—from topography and climate to community succession—yet a singular, all-encompassing theory for species richness across multiple taxa in mountain ecosystems remains elusive. In this research, we explored the causes of species richness in mountain multiple-taxa in terms of spatial attributes of protected areas, human disturbance and environmental factors. Initiating our study, we compiled a comprehensive database of all national nature reserves (NNRs) situated in the karst regions of Guizhou province. This was achieved through an extensive multidisciplinary field survey in recent years, resulting in a collection of 40,570 species records. Subsequently, we discerned a complex interplay between species richness, spatial attributes, human disturbance, and environmental factors, which collectively account for over 80 % of the observed variations in mountain biodiversity. Our findings revealed several intricate relationships: Shape index and fragmentation positively influenced the richness of insect, animal, and seed plant species. Conversely, anthropogenic alterations and nighttime light negatively impacted the diversity of amphibians, reptiles, and mammals. Interestingly, we discovered a significant positive association between the richness of fungi, mosses, and ferns and the variables of soil texture and soil water, demonstrating the importance of soils in karst for maintaining biodiversity. To conclude, we evaluated conservation strategies in mountainous regions. It is imperative that the spatial configuration of protected areas be refined to alleviate the detrimental effects of human disturbance. Furthermore, conservation efforts should be customized to the unique climatic and geographic conditions found locally.

Anthropogenic activities decrease functional richness over time, but not other functional aspects of the fish community in a tropical bay

Functional diversity can be used to help understanding the processes shaping biological communities and the effects of human disturbances on the ecosystem's services. Untangling these biological processes is crucial to apply effective policies aiming the biodiversity conservation. Temporal changes (1983–1985, 1999–2001 and 2017–2019) in five functional indices (functional richness, divergence, evenness, specialization and originality) of the fish communities in two zones (inner and outer) of shallow areas in a tropical bay heavily human-impacted in recent decades were evaluated. The tested hypothesis was that functional indices decrease over time, because of the environmental degradation. A substantial decrease in species richness and abundance in the more recent periods (1999–2002 and 2017–2019) compared to 1983–1985 was observed. However, the functional structure remained relatively stable, with the exception of functional richness that showed a significant decrease over time. The apparent stability in the other functional indices may be due to the presence of dominant and functionally redundant species over time that compensates for the loss of species while maintaining similar functions. It was also discovered that decreases in fish richness in shallow bay areas result in losses in functional richness, with resident fish and benthivorous species being the most affected by environmental degradation. By employing a comprehensive approach that integrates the use of functional indices and taxonomic diversity to assess temporal changes in the fish community, it provides a broader understanding of ecological processes. Such insights could prove invaluable in guiding the implementation of conservation strategies.

Population status of a nocturnal primate (the Philippine tarsier- Carlito syrichta, Linnaeus, 1758) in an agricultural area of Subayon, Bilar, Bohol.

The destruction of wildlife habitats due to the exponential growth of human population and its encroachment into wild areas is a major threat to many species around the world. In order to understand the effects of human disturbance on the Philippine tarsier (Carlito syrichta), we evaluated its population status by quantifying the species' population density in an agricultural habitat and assessed the degree of human disturbance in the area. We did the study in Subayon, Bilar, Bohol, where we surveyed 32ha out of the total 115ha of the village between April and June 2017. We predominantly used vocal activity to identify the presence and absence of tarsiers, supplementing the data with incidental sightings. In addition, human disturbances were assessed and described qualitatively. We estimated the population density on 75 individuals per square kilometer. The human disturbance was evidenced in 28 out of 32 plots, which indicates that the entire area has already been disturbed. This study showed that the Philippine tarsier could inhabit highly altered habitats such as agricultural landscapes and suggest that Subayon village might be important for the conservation of this species. We provided another example of the ecological flexibility of otherwise specialised nocturnal primates able to inhabit agricultural areas. To avoid conflicts with humans and to conserve such a species in the future, education, outreach and active involvement of local people are essential.

Negative effects of human disturbance and increased aridity on root biomass and nutrients along the regeneration of a tropical dry forest in the context of slash-and-burn agriculture

Biomass is an important indicator of the ability of tropical forests to deliver ecosystem services, but little attention has been given to belowground biomass and its drivers in human-modified landscapes. Here, we investigated the belowground biomass and nutrient concentration/stocks (C, P, and N) across regenerating forest stands with varying ages (10–76 years old) and old-growth forests in the Caatinga dry forest (northeastern Brazil) in the context of slash-and-burn agriculture. Belowground biomass ranged from 1.89 ± 0.33 Mg ha−1 to 17.53 ± 2.28 Mg ha−1 (mean ± SE) across regenerating forest stands and averaged 8.33 ± 1.59 Mg ha−1, with no differences compared to old-growth stands. However, regenerating stands exhibited a higher root/shoot ratio with biomass concentrated in the superficial soil layer and in large-sized roots, regardless of the successional stage. Root nutrient concentration and stocks were highly variable across forest stands with fine roots supporting a higher concentration of N and P, while regenerating stands supported lower nutrient stocks as compared to old-growth forests. Finally, precipitation and chronic disturbance emerged as the most important drivers of belowground biomass and nutrient concentrations/stocks, while aboveground biomass played a negligible role. Our results indicate that, in human-modified landscapes of tropical dry forests, belowground biomass and nutrients play important roles in ecosystem functions in regenerated forests after slash-and-burn agriculture. Forest resilience and provision of ecosystem services (e.g., nutrient cycling) appear to be very sensitive to increased aridity and exploitation of forest resources.

Eutrophication modifies the relationships between multiple facets of macroinvertebrate beta diversity and geographic distance in freshwater lakes

AbstractAimUnderstanding the distance–decay relationship (DDR) has been considered important because it reflects a combination of several ecological processes such as dispersal limitation and environmental sorting. However, effects of human disturbances on DDR are poorly known, especially in freshwater lakes. This study is aimed to examine how anthropogenic eutrophication modified the relationships between three facets (taxonomic, functional and phylogenetic) of macroinvertebrate beta diversity and geographic and environmental distances across 30 freshwater lakes.LocationThe Yangtze River floodplain, China.MethodsWe used Mantel tests to examine the relationships between multiple facets of assemblage dissimilarities (overall beta diversity, replacement and richness difference components) and geographic and environmental distances. Distance‐based redundancy analysis (dbRDA) and associated variation partitioning procedures were applied to explore the relative contributions of environmental and spatial factors on the three facets of beta diversity.ResultsWe found that none of the three beta diversity facets was related to geographic distance, but all were significantly related to environmental distance, mainly mirroring eutrophication‐related variables. Based on the variation partitioning approach, the macroinvertebrate assemblages examined were almost exclusively structured by environmental factors associated with eutrophication, while spatial variables had a negligible effect. Nevertheless, the different facets of beta diversity did not decrease (i.e., no homogenization trend) in lake groups showing the highest eutrophication levels, implying complex influences of anthropogenic disturbances in driving homogenization or differentiation in assemblage compositional dissimilarity.Main ConclusionsOur findings suggested that the high degrees of eutrophication acted as an environmental filter to significantly modify the spatial distance–decay relationships, possibly via decreasing the importance of dispersal limitation in shaping macroinvertebrate assemblages in the studied lakes. Given the sensitivity of beta diversity patterns to eutrophication we found in this study, we recommend that the role of anthropogenic disturbances should be incorporated into research on general ecological patterns like the DDR.

Effects of human disturbance on detectability of non-breeding birds in urban green areas

Animals adapted to disturbed habitats have evolved multiple behavioural strategies, spanning from hiding to displacing to less disturbed microhabitats. Urban areas pose new evolutionary challenges since animals often need to deal with novel environmental conditions. In this context, urban parks may constitute biodiversity hotspots within the concrete jungle. Nonetheless, the recent increase in recreational activities in urban parks potentially puzzles the ability of urban-dwelling animals to exploit these environments. In this study, we evaluated the effect of human disturbance and other contextual variables on the activity patterns of four bird species commonly found in European urban parks, covering a wide range of ecological characteristics: the blackbird (Turdus merula), the hooded crow (Corvus cornix), the Eurasian robin (Erithacus rubecula), and the wood pigeon (Columba palumbus). We performed repeated counts of these bird species in six urban parks in northern Italy and we fitted Bayesian N-mixture models to estimate the relationship between detection probability and human disturbance (number of people present in the park), phenology (date and time of the day), and weather conditions (temperature and precipitation). For all the species but the blackbird, we found a negative relationship between the number of people present in the park and the detection probability of the focal species. We also found species-specific effects of both phenology and weather conditions on the detection probability. Our results suggest that urban dwelling species can finely modulate their activity patterns in response to the level of human disturbance, suggesting a possible key role of behavioural phenotypic plasticity. Furthermore, uncovering patterns of detectability of urban fauna can help in planning biodiversity monitoring and conservation, as it provides useful information to carry out surveys when the probability of detecting individuals is highest, optimising resource investments and reliability of biodiversity estimates.

Effects of human disturbances on wildlife behaviour and consequences for predator-prey overlap in Southeast Asia

Some animal species shift their activity towards increased nocturnality in disturbed habitats to avoid predominantly diurnal humans. This may alter diel overlap among species, a precondition to most predation and competition interactions that structure food webs. Here, using camera trap data from 10 tropical forest landscapes, we find that hyperdiverse Southeast Asian wildlife communities shift their peak activity from early mornings in intact habitats towards dawn and dusk in disturbed habitats (increased crepuscularity). Our results indicate that anthropogenic disturbances drive opposing behavioural adaptations based on rarity, size and feeding guild, with more nocturnality among the 59 rarer specialists’ species, more diurnality for medium-sized generalists, and less diurnality for larger hunted species. Species turnover also played a role in underpinning community- and guild-level responses, with disturbances associated with markedly more detections of diurnal generalists and their medium-sized diurnal predators. However, overlap among predator-prey or competitor guilds does not vary with disturbance, suggesting that net species interactions may be conserved.