Types Of Human Disturbance Research Articles

Habitat visibility affects the behavioral response of a large herbivore to human disturbance in forest landscapes

Wildlife can perceive humans as predators and human disturbance, whether lethal (e.g., hunting) or non-lethal (e.g., hiking, biking, and skiing), triggers antipredator behavior among prey. Visibility is the property that relates habitat structure to accessibility of visual information that allows animals to detect predators and evaluate predation risk. Thus, the visibility of a habitat (hereafter referred to as habitat visibility) for prey species alters the perceived risk of predation and therefore has a strong influence on their antipredator behavior. Yet, knowledge of how habitat visibility affects the response of animals to different types of human disturbance is limited, partly, because it is challenging to measure habitat visibility for animals at a fine spatial scale over a landscape, particularly in highly heterogeneous landscapes (e.g., forests). In this study, we employed a newly described approach that combines terrestrial and airborne LiDAR to contiguously measure fine-scale habitat visibility in a forested landscape. We applied the LiDAR-derived habitat visibility to examine how habitat visibility in forests affects the summer space use of 20 GPS-collared female red deer (Cervus elaphus) modeled with integrated step-selection functions in the Bavarian Forest National Park, Germany when exposed to various types of human disturbance including recreational activities, forest roads, hiking trails, and hunting. We found that red deer in our study area avoided areas with higher all types of human disturbance, especially during daylight hours. Furthermore, habitat visibility significantly modified the use of space by red deer in response to human recreational activities, forest roads, and hiking trails, but not to the hunting area. Red deer tended to tolerate a higher intensity of human recreational activities and to use areas closer to forest roads or hiking trails when they have lower habitat visibility (i.e., more cover). Our findings highlight the importance of considering visual perception when studying the response of wild animals to human disturbance. We emphasize the potential to mitigate negative consequences of human disturbance on wildlife, through measures such as maintaining vegetative buffers around recreational infrastructure (e.g., roads and skiing tracks) in order to reduce habitat visibility around areas frequented by humans.

Effects of Different Types of Human Disturbance on Total and Nitrogen-Transforming Bacteria in Haihe River.

Haihe River is the largest water system in North China and is injected into the Bohai Sea in Tianjin City. In this study, different types of human disturbance (urban sewage, industrial pollution, ship disturbance) were selected from the upper reaches of Haihe river Tianjin section down to the estuary that connected with Bohai Sea for evaluation. By metagenomic sequencing, the effects of different types of disturbances on bacteria communities in Haihe sediments were studied, with a special focus on the function of nitrogen-cycling bacteria that were further analyzed through KEGG comparison. By analyzing the physical and chemical characteristics of sediments, results showed that human disturbance caused a large amount of nitrogen input into Haihe River, and different types of human disturbance led to distinct spatial heterogeneity in different sections of Haihe River. The bacteria community was dominated by Proteobacteria, followed by Chloroflexi, Bacteroidetes, Actinobacteria and Acidobacteria. The relative abundance of each phylum varied at different sites as a response to different types of human disturbances. In nitrogen cycling, microorganisms including nitrogen fixation and removal were detected at each site, which indicated the active potential for nitrogen transformation in Haihe River. In addition, a large number of metabolic pathways relating to human diseases were also revealed in urban and pollution sites by function potential, which provided an important basis for the indicative role of urban river ecosystem for public health security. In summary, by evaluating both the ecological role and function potential of bacteria in Haihe River under different types of human disturbance, the knowledge of microorganisms for healthy and disturbed river ecosystems has been broadened, which is also informative for further river management and bioremediation.

Impacts of human disturbance on flight response and habitat use of red deer

AbstractMany wild animals perceive humans as predators, and human disturbance, especially in the form of hunting, triggers antipredatory behavior among prey. Yet, knowledge of how game species react to different types of human disturbance and adapt to repeated disturbances is limited. We investigated how disturbance in the form of a solitary human approacher (stalker) impacted behavior (flight response and short‐term habitat use) of 28 GPS‐collared red deer (Cervus elaphus) in two populations with contrasting population densities in Norway. We studied how the behavioral response differed: (1) with season (pre‐hunting vs. hunting); (2) by consecutive approaches within a day; (3) among replicated experiments within the same season; and (4) between two regions with contrasting densities of red deer. The average flight initiation distance (FID) increased by 15% during the hunting season, and consecutive approaches within the same day caused the red deer to move 49% longer distances. Flight initiation distance was longer in the high‐density population, while escape distance was longer in the low‐density population. Red deer moved out of their weekly home range after 52% approaches, and after the onset of hunting season, time spent outside the home range increased by 89%. Red deer preferred denser resting sites after the disturbance and animal sites had shorter sighting distance and higher canopy cover than control plots. Tree density and canopy cover at animal sites increased at the onset of hunting season, from first to second approach within day, and after replicated experiments within season. Our results suggest that red deer preferred dense resting sites, especially in the hunting season. However, these animal sites had the same amount of the favorable forage plant bilberry (Vaccinium myrtillus), indicating no clear food–cover trade‐off in selection of habitat. Our study showed that onset of hunting initiates stronger fear responses in red deer, which may in turn affect red deer distribution and harvesting efficiency.

Combining functional diversity of lotic fish communities with river health assessment based on multi-metric chemical pollution and biological integrity index models

Trait-based functional studies are widely used to elucidate the relationships between ecological indicators and environmental parameters as well as to predict functional change in aquatic biota in response to various types of human disturbance. Clarifying how functional traits of aquatic organisms depend on environmental conditions can facilitate aquatic conservation and management, but determining the importance of these traits to ecological river health requires further investigation. As fish play a key role in the assessment of ecological conditions, we examined the relevance of the functional diversity of lotic fish to the river health assessment using multi-metric models of water pollution (mWPI) and fish-based biological integrity (mIBI). Twelve fish traits related to food acquisition, environmental stability, and mobility were used for the functional analyses. Chemical river health was highly sensitive to downstream organic matter and nutrient pollution according to mWPI. Based on the present gradient of chemical health and water chemical variables, we identified three water quality groups (G-I, G-II, and G-III). G-I, G-II, and G-III showed low, intermediate, and high levels of water quality degradation, respectively. Spatially significant differences among these groups were observed for both the taxonomic and functional structures of lotic fish as well as ecological river health based on mIBI. The dominance of sensitive species was high in G-I, whereas tolerant and exotic species contributed strongly to the species compositions of G-II and G-III. Functional richness and dispersal were significantly reduced in G-III, and their decreases correlated with ecological health and the loss of species that are insectivorous, rheophilic, and sensitive to water pollution. Regarding redundancy analyses, both the models of functional trait metrics (F = 8.06, p < 0.001) and mIBI metrics (F = 4.88, p < 0.01) indicated good performance in terms of the variation in water quality and chemical river health parameters. Overall, the functional trait-based diversity of lotic fish is significant to the assessment of ecological river health and reflects water chemical quality. This association arises because niche occupation in functional space by all species, along with their abundance distribution, is highly responsive to the loss of species with sensitive traits due to water pollution.

Effects of forest ropeway construction on bird diversity and its seed dispersal mutualism for endangered Taxus chinensis, southeast China

The mechanism by which different types of human disturbance (fragmentation, urbanization, hunting, and selective logging) affect bird seed dispersal is well established. However, knowledge about how seed dispersal responds to forest ropeway development is still unknown. Here, we studied the influence of the forest ropeway construction, ranging from the pre-construction to the post-construction stage, including the construction stage, on bird diversity and its seed dispersal mutualism for endangered Chinese yew, Taxus chinensis. Our results first showed how bird diversity response to the disturbance of ropeway construction. Species number and Shannon-Wiener diversity decreased from pre-construction to construction stage, and then increased in the post-construction stage. Body size was an important indicator to explore the foraging pattern of birds across all stages. Furthermore, the network in three stage showed a random structure with a high connectivity and low specialization. Moreover, weak value of species degree, species strength and partner diversity was found in the construction stage. Most importantly, Hypsipetes leucocephalus was the most important disperser species in the whole stage due to its high value of species strength. Our results fills important gaps in our identification of how bird diversity and its seed dispersal mutualism response to the disturbance of forest tourism development. Our study also has relevant implications for the conservation of these increasingly disturbed ecosystems

Natural forest growth and human induced ecosystem disturbance influence water yield in forests

Together natural growth, afforestation and forest disturbance, such as felling, contribute to the dynamic nature of forests. Thus to enhance forest management, water resource management and carbon sequestration, the net effect of forest changes on water yield must be better understood. Here, we conduct a global meta-analysis of 496 watersheds over 25 years to investigate the impact of forest complexity and overall changes on water yields. We classify watersheds based on the type of human disturbance, including felling and thinning, afforestation, and absence of external disturbances. We find that the runoff coefficient (ratio of annual water yield in watershed outlet to precipitation) is more sensitive to external disturbances in forests with lower ecosystem complexity compared to forests with higher complexity. In addition, we found forest natural growth may increase runoff and lead to an increased runoff coefficient decades later. Our findings highlight the importance of nature-based forest restoration, especially in regions vulnerable to water shortage.

Intra‐population variation in male nuptial coloration and diet across anthropogenically altered visual microhabitats in an African cichlid

Human activities are altering natural ecosystems, leading to widespread environmental change that can vary across spatiotemporal scales, thus creating dynamic, novel conditions at both large and small scales. In highly disturbed aquatic systems, elevated turbidity is one common stressor that alters the sensory environment of fishes and can disrupt communication, including mate choice, driving population-level shifts in visual communication traits such as nuptial coloration. At a smaller, within-population scale, we can expect similar adaptive divergence to a heterogeneous visual landscape. Using the cichlid fish, Pseudocrenilabrus multicolor, we investigated within-population variation in diet and nuptial coloration by sampling fish from microhabitats within a relatively small site (~0.14 km2). These visual microhabitats are affected by different types of human disturbance at a very small scale leading to significant differences in water clarity (i.e. turbidity). We used three, non-mutually exclusive working hypotheses to test if (1) males in low turbidity invest more in carotenoid-based coloration (economy of pigments hypothesis), (2) fish from low-turbidity sites eat more carotenoid-rich foods (diet hypothesis), and (3) fish are habitat matching. Stomach content analyses revealed relatively high overlap in diet across microhabitats; however, fish from stations with the lowest turbidity consumed relatively more plant material (high in carotenoid content) than fish captured at high-turbidity stations. Males from clearer waters displayed significantly more carotenoid-based, red and yellow coloration than fish found in microhabitats with higher turbidity, similar to between-population color variation in this species. Furthermore, larger fish displayed more carotenoid coloration overall, but there was no difference in mean male size among microhabitats suggesting that fish were not sorting into microhabitats. Our results suggest that within-population variation in nuptial coloration could be associated with microhabitat heterogeneity in the visual landscape driven by turbidity, a diet with more carotenoid-rich prey items, or a combination of both.

Morphological adjustments of the lower Orba River (NW Italy) since the mid-nineteenth century

A multi-temporal and multi-scale analysis based on historical data collection and review, maps and aerial photograph interpretation, field observations, topographic surveys, and GIS investigations was performed to (i) examine the morphological evolution of lower Orba River since the mid-nineteenth century, (ii) identify its controlling factors, and (iii) correctly interpret ongoing hydrogeomorphic conditions under a river management perspective. The riverbed experienced overall slight and non-homogeneous morphological adjustments, along with some horizontal displacements, up to the early twentieth century (Phase 0). Subsequently, two phases of channel degradation were identified. The first, from the 1920s to the 1950s (Phase 1), is characterized by slight narrowing (12.3%), the beginning of incision, and rare and little lateral migration. The second, between the 1950s and the years around 2010 (Phase 2), displays significant channel incision (mostly from the 1950s to the 1970s, from 0–1 m to 4–5 m), weak narrowing (21.0%), and only minor horizontal displacements. Over the last decade (Phase 3), widespread slight channel widening (3.4%, up to 25.7% at the reach scale) associated with the absence of a generalized bed-level variation trend was observed. The study reach has exhibited a single-thread or transitional channel since the mid-nineteenth century. Channel incision was mainly caused by extensive in-channel sediment extractions primarily carried out between the 1950s and the early 1980s at the reach and catchment scales. The long-term presence of widespread channelization works was recognized as the main reason why overall little riverbed planform adjustments occurred during the whole period investigated. The most recent dynamics were triggered by floods and were interpreted as the river response to human-induced alterations. The riverbed changes that occurred during the twentieth century match the channel adjustments commonly experienced by Italian single-thread and transitional channels as a response to various types of human disturbances. However, the detected morpho-evolutionary phases of the Orba River are only partially in agreement with those reported in the literature for other Italian rivers affected by similar anthropogenic pressures, as some differences exist in timing and magnitude of prevalent channel adjustments. An overall slight potential for channel recovery, priorities for rehabilitation, and the main objectives for the next-decades management were identified. This research provides insights into the medium- and short-term morphological evolution of Italian rivers, and its outcomes represent an essential piece to drive river management towards sustainable and effective river restoration and risk mitigation measures framed within a larger, multidisciplinary, and objective-based context. A wide spectrum of both consolidated and newly developed GIS-based planform metrics was considered to assess the channel morphological evolution in detail, providing an operative reference framework for future investigations.

The pace of modern life, revisited.

Wild populations must continuously respond to environmental changes or they risk extinction. Those responses can be measured as phenotypic rates of change, which can allow us to predict contemporary adaptive responses, some of which are evolutionary. About two decades ago, a database of phenotypic rates of change in wild populations was compiled. Since then, researchers have used (and expanded) this database to examine phenotypic responses to specific types of human disturbance. Here, we update the database by adding 5675 new estimates of phenotypic change. Using this newer version of the data base, now containing 7338 estimates of phenotypic change, we revisit the conclusions of four published articles. We then synthesize the expanded database to compare rates of change across different types of human disturbance. Analyses of this expanded database suggest that: (i) a small absolute difference in rates of change exists between human disturbed and natural populations, (ii) harvesting by humans results in higher rates of change than other types of disturbance, (iii) introduced populations have increased rates of change, and (iv) body size does not increase through time. Thus, findings from earlier analyses have largely held-up in analyses of our new database that encompass a much larger breadth of species, traits, and human disturbances. Lastly, we use new analyses to explore how various types of human disturbances affect rates of phenotypic change, and we call for this database to serve as a steppingstone for further analyses to understand patterns of contemporary phenotypic change.

Functional diversity loss and change in nocturnal behavior of mammals under anthropogenic disturbance.

In the Anthropocene, understanding the impacts of anthropogenic influence on biodiversity and behavior of vulnerable wildlife communities is increasingly relevant to effective conservation. However, comparative studies aimed at disentangling the concurrent effect of different types of human disturbance on multifaceted biodiversity and on activity patterns of mammals are surprisingly rare. We applied a multiregion community model to separately estimate the effects of cumulative human modification (e.g., settlement, agriculture, and transportation) and human presence (aggregated presence of dogs, people, and livestock) on species richness and functional composition of medium‐ and large‐bodied mammals based on camera trap data collected across 45 subtropical montane forests. We divided the detected mammal species into three trophic guilds–carnivores, herbivores, and omnivores–and assessed the nocturnal shifts of each guild in response to anthropogenic activities. Overall, species richness tended to increase (β coefficient = 0.954) as human modification increased but richness decreased as human presence increased (β = –1.054). Human modification was associated with significantly lower functional diversity (mean nearest taxon distance [MNTD], β = –0.134; standardized effect sizes of MNTD, β = –0.397), community average body mass (β = –0.240), and proportion of carnivores (β = –0.580). Human presence was associated with a strongly reduced proportion of herbivores (β = –0.522), whereas proportion of omnivores significantly increased as human presence (β = 0.378) and habitat modification (β = 0.419) increased. In terms of activity patterns, omnivores (β = 12.103) and carnivores (β = 9.368) became more nocturnal in response to human modification. Our results suggest that human modification and human presence have differing effects on mammals and demonstrate that anthropogenic disturbances can lead to drastic loss of functional diversity and result in a shift to nocturnal behavior of mammals. Conservation planning should consider concurrent effects of different types of human disturbance on species richness, functional diversity, and behavior of wildlife communities.

Impact of human disturbances on soil cyanobacteria diversity and distribution in suburban arid area of Marrakesh, Morocco

BackgroundCyanobacteria are among the first photoautotrophic component of soil microorganism communities which play a key ecological role in nutrient cycles and soil productivity. However, the sustainability of these soil biodiversity ecosystem services is increasingly compromised, especially in urban and peri-urban areas where soils are heavily exploited and used for a wide range of human activities. The aim of this study is to assess the impact of different types of human disturbances on cyanobacteria diversity and distribution in suburban soils of Marrakesh. Soil and cyanobacteria sampling were carried out during two campaigns at six sites located along an anthropogenic gradient from the least urbanized suburbs of Marrakesh to the highly anthropized suburban area. In the laboratory, soil physicochemical characteristics were measured. The morphological identification of cyanobacteria species was based both on microscopic observation and on soil cultures in solid and liquid Z8 media.ResultsThe results showed a total of 25 cyanobacteria taxa belonging to ten genera, four families, and two orders (Oscillatoriales 88% and Chroococcales 12% of taxa). Among the taxa identified, seven strains were isolated in soil culture in nutrient media and purified in monoalgal culture. The highest cyanobacterial diversity was recorded in irrigated soil with treated wastewater compared to the non-cultivated control soil. In Principal Component and Cluster Analysis, suburban soils were subdivided into three groups depending on the chemical properties and cyanobacteria composition. Cyanobacteria diversity was significantly associated with the soil moisture, total organic carbon (TOC), PO4-P, NO3-N, and NH4-N contents.ConclusionsWhile diversity and microalgal biomass were significantly lower in the soils affected by municipal and mining solid wastes, the input of organic matter and nutrients from treated wastewater appears to be beneficial for the increasing of the biodiversity of soil cyanobacteria. This survey provides a first inventory of the soil cyanobacterial communities and shows their spatial variability and high sensitivity to the land-use practices and anthropogenic disturbances on urban soil in Moroccan drylands.

Ecological status of coralligenous assemblages: Ten years of application of the ESCA index from local to wide scale validation

This paper aims at collating and reviewing all data collected using the ESCA (Ecological Status of Coralligenous Assemblages) index from 2009 to 2018 during different local applications, in order to evaluate at large spatial scale its effectiveness and temporal variability. To this scope, the large-scale response of ESCA to anthropogenic disturbance was tested comparing ESCA values calculated at 42 sites of the Western Mediterranean Sea with the anthropization index. Moreover, the sensitivity of ESCA to punctual human disturbance and the robustness of the index across the natural space and time variability were evaluated. The large spatial scale study showed significant correlation between ESCA and the anthropization index, while very low correlation was detected when descriptors of ESCA (i.e., sensitivity levels, α-diversity, and β-diversity) were considered separately. The three impact evaluation studies highlighted significantly lower values of the ESCA index in disturbed conditions than in the control ones. The coastal monitoring study confirmed the robustness of the index which showed a high ecological quality of coralligenous reefs in reference conditions compared to more anthropized sites, and this pattern was maintained throughout the ten years study period. Application of the ESCA index to different situations tested positively its sensibility to different levels and type of human disturbance and its stability with respect to regional spatio-temporal variability. This confirm the reliability of the ESCA index already tested on the local and annual scale, thus broadening its range of application and validating it on a wider space–time scale.

Human disturbance has contrasting effects on niche partitioning within carnivore communities.

Among species, coexistence is driven partly by the partitioning of available resources. The mechanisms of coexistence and competition among species have been a central topic within community ecology, with particular focus on mammalian carnivore community research. However, despite growing concern regarding the impact of humans on the behaviour of species, very little is known about the effect of humans on species interactions. The aim of this review is to establish a comprehensive framework for the impacts of human disturbance on three dimensions (spatial, temporal and trophic) of niche partitioning within carnivore communities and subsequent effects on both intraguild competition and community structure. We conducted a systematic review of the literature on carnivore niche partitioning (246 studies) and extracted 46 reported effects of human disturbance. We found evidence that human disturbance impacts resource partitioning, either positively or negatively, in all three niche dimensions. The repercussions of such variations are highly heterogeneous and differ according to both the type of human disturbance and how the landscape and/or availability of resources are affected. We propose a theoretical framework of the three main outcomes for the impacts of human disturbance on intraguild competition and carnivore community structure: (i) human disturbance impedes niche partitioning, increasing intraguild competition and reducing the richness and diversity of the community; (ii) human disturbance unbalances niche partitioning and intraguild competition, affecting community stability; and (iii) human disturbance facilitates niche partitioning, decreasing intraguild competition and enriching the community. We call for better integration of the impact of humans on carnivore communities in future research on interspecific competition.

Effects of forest trails on the community structure of tropical butterflies

Understanding the ecological impacts of human disturbances is essential for the formulation of conservation strategies. This study aimed to investigate if unpaved trails (with about 5 to 6 m wide) inside forests can cause ecological changes in their surroundings. The studied group was the fruit-feeding butterflies, since they usually respond to habitat disturbances through changes in species composition. This group is also known to present a distinct distribution along a vertical gradient in tropical forests. However, in open areas, some canopy species are observed reaching the ground. Based on that, we address the following hypotheses: (1) trails inside the forest cause a disruption in the vertical stratification pattern of fruit-feeding butterfly assemblages, and (2) trails modify their community parameters. The study was carried out in a protected area in the Atlantic Forest. Butterflies were sampled monthly through 2 years with bait traps distributed in the canopy and the understory in two habitat types: (1) forest interior, and (2) edges parallel to a trail opening. Our results showed that the understory edge had a greater abundance of individuals and lower species richness when compared to the forest interior. However, the trails did not disrupt the vertical stratification pattern or modify the species composition of fruit-feeding butterflies. Therefore, their effect was not as strong as other types of human disturbances. The present results suggest trails inside forests presented a relatively low impact in the adjacent biological communities, preserving the habitat for several forest organisms and maintaining the vertical structure of biological communities along them.

Gut microbiota composition of Japanese macaques associates with extent of human encroachment.

In recent decades, human-wildlife interaction and associated anthropogenic food provisioning has been increasing and becoming more severe due to fast population growth and urban development. Noting the role of the gut microbiome in host physiology like nutrition and health, it is thus essential to understand how human-wildlife interactions and availability of anthropogenic food in habitats can affect an animal's gut microbiome. This study, therefore, set out to examine the gut microbiota of Japanese macaques (Macaca fuscata) with varying accessibility to anthropogenic food and the possibility of using gut microbiota as indicator for macaques' reliance on anthropogenic food. Using 16S ribosomal RNA gene sequencing, we described the microbial composition of Japanese macaques experiencing different types of human disturbance and anthropogenic food availability-captive, provisioned, crop-raiding, and wild. In terms of alpha diversity, our results showed that observed richness of gut microbiota did not differ significantly between disturbance types but among collection sites, whereas Shannon diversity index differed by both disturbance types and sites. In terms of beta diversity, captive populations harbored the most distinctive gut microbial composition, and had the greatest difference compared with wild populations. Whereas for provisioned and crop-raiding groups, the macaques exhibited intermediate microbiota between wild and captive. We identified several potential bacterial taxa at different taxonomic ranks whose abundance potentially could help in assessing macaques' accessibility to anthropogenic food. This study revealed the flexibility of the gut microbiome of Japanese macaques and provided possible indices based on the gut microbiome profile in assessing macaques' accessibility to/reliance on anthropogenic foods.

Disturbance control can effectively restore the habitat of the giant panda (Ailuropoda melanoleuca)

Expanding human disturbances on a global scale are encroaching upon wildlife habitat. Management of human–wildlife conflict is an important issue in biodiversity conservation. Conservation decisions are supported by information on how many habitats could be recovered by controlling human disturbances, yet it has rarely been quantitatively studied. Giant pandas (Ailuropoda melanoleuca) are still confronted with threats of human disturbance even though populations have been restored in recent decades. In this study, the impact of four types of human disturbance, including livestock, infrastructure, farming and other disturbances were assessed based on a dataset that covers 75% of total giant panda population. Five scenarios where disturbances are controlled were used to evaluate the habitat area that can be restored by controlling disturbance. Results revealed that 2102 km2 of suitable habitat can be restored if all these disturbances were completely controlled. Controlling livestock alone can restore up to 830 km2 of habitat, much more than controlling farming or infrastructure. Controlling infrastructure restored more habitat than the other disturbances in the Daxiangling and Qionglai Mountains. Moreover, in the Minshan Mountains, controlling agriculture resulted in the most habitat restoration. It appears, the reserves system does work in controlling the three types of human disturbance, however, more control is needed over human disturbances in order to restore wildlife habitat outside of the reserves. These results not only calculate how much giant panda habitat can be restored by controlling disturbance, but also provide insights for other species habitat management.

Successional stage effect on the availability of tree cavities for cavity-nesting birds in an Atlantic Forest park from the state of São Paulo, Brazil

Abstract The availability of suitable cavities and substrate for hole construction can limit the populations of birds that rely on tree hollows to reproduce. Several studies have focused on the effects of types of habitats, and types of human disturbances on cavities abundance, but the effect of successional stages in the Atlantic Forest has been poorly addressed. In this study we aimed to compare the availability and biometric characteristics of tree cavities between primary and mid-successional stage sites in an Atlantic Forest area from southeastern Brazil. Based on nest characteristics described in the literature, we inferred if hollows present in secondary sites could harbor the large secondary-nester Atlantic Forest birds, with special attention to toucans and hawks. From September 2016 to April 2017, 96 cavities were sampled, 67 in the primary, and 29 in the secondary plots. Our data revealed that the communities of cavity-nester birds in mid-successional stage areas may be more affected by the reduced cavity availability than by cavities quality, as the number of cavities in these sites was less than half than that found in mature forests. We also provide evidences that the largest cavity nesters, such as the biggest hawks, might have limited nesting possibilities in mid-successional stage areas especially due to small cavity entrances, which may have important reflects in conservation strategies.

Primate responses to anthropogenic habitat disturbance: A pantropical meta-analysis

Rapid human-induced conversion and degradation of natural habitats has severely altered patterns of species occupancy and population viability. Primates are highly vulnerable to tropical forest loss and degradation because they are highly arboreal, forest-dependent, and often highly sensitive to changes in forest structure. Here we quantify the effects of anthropogenic habitat modification on primate community structure using a global meta-analysis based on 72 studies to understand the variation in effect sizes between biogeographic regions, types of human disturbance, trophic levels of primate species, and sampling design protocols. We examined response ratios for 637 comparisons between disturbed forests and adjacent ‘pseudo-control’ forests with a history of little or no impact. This revealed an overall decrease of 30% (95% CI: 17–43%) in biodiversity metrics in response to habitat disturbance, which was particularly detrimental to primate assemblages in Madagascar and Southeast Asia. This effect was more severe in areas converted to agriculture (77%; 95% CI: 59–88%), while land use intensification led to far more detrimental effects than the initial degradation of forests, calling for the identification of habitat degradation thresholds. Negative effects of forest degradation were further exacerbated by ~30% under scenarios of persistent hunting pressure, emphasizing possible synergistic interactions between environmental stressors. Given that overall primate diversity was depressed in degraded habitats, our results emphasize the importance of retaining connectivity across remnants of undisturbed primary forest within human-modified landscapes to maintain full complements of primate species, and ensure their long-term persistence.

Effects of recreational activities on Patagonian rocky shores

Recreational activities can be an important source of anthropogenic disturbance in intertidal benthic assemblages. On rocky shores, activities such as trampling, snorkeling and the handling of organisms may have a negative effect on benthic communities by modifying the abundance and distribution of key species. Here, we describe and quantify impacts due to recreational activities on benthic communities on a Patagonian rocky shore by investigating their resilience to two types of human disturbance: vehicle traffic and human trampling. To evaluate the effects of these activities, we carried out an observational study and assessed post-disturbance assemblage recovery. The rocky shores is most intensively visited during summer, and marked differences in the distribution and abundance of benthic species among disturbed and control plots were found after this season. The benthic community on the high intertidal was weakly impacted by disturbance generated due to vehicle traffic in summer (one vehicle on a single occasion, pulse disturbance); which did not affect the cover of dominant species. This suggests that the high intertidal community would be resistant to the passage of one vehicle on a single occasion. The effects of continuous trampling (press disturbance) were drastic and the community of the mid intertidal level did not recover before the next recreational season. Mid intertidal communities exposed to press disturbances require more than one tourist season of human inactivity to recover from anthropogenic effects, suggesting that resilience mechanisms in this community operate at broad timescales. Our findings highlight the need to establish and implement management actions that contemplate the nature of the disturbance and intertidal level to minimize habitat degradation due to human recreational activities.

Relationship between human disturbance and Endangered giant panda Ailuropoda melanoleuca habitat use in the Daxiangling Mountains

AbstractThe Endangered giant panda Ailuropoda melanoleuca is one of the most threatened mammals. The species has experienced declines in its population and habitat as a result of human disturbance. We investigated the influence of human disturbance on habitat use by giant pandas in the Daxiangling Mountains, in China's Sichuan Province. We mapped all signs of giant panda and all locations of seven types of human disturbance in the study area. We used correlation analysis, generalized linear models, and Akaike information criteria to analyse the influence of the various types of human disturbances on habitat use by the giant panda. Our results showed that habitat use was positively correlated with elevation and distance from roads, residences, hydropower stations and logging or tree-felling sites, but negatively correlated with distance from bamboo shoot collection sites and trap sites. We found that the road-effect zone spanned a distance of c. 1,200 m and that human residence could affect the intensity of habitat use by giant pandas at distances > 2,500 m. The effect of roads on habitat use was probably influenced by the association of roads with residences, hydropower stations and mines. In the area occupied by giant pandas, we recommend increased regulation to minimize the expansion and impact of roads, residences, hydropower stations and logging activities.