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1
Kiffner, Christian, Filipa M. D. Paciência, Grace Henrich, et al. "Road-based line distance surveys overestimate densities of olive baboons." PLOS ONE 17, no. 2 (2022): e0263314. http://dx.doi.org/10.1371/journal.pone.0263314.
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Estimating population density and population dynamics is essential for understanding primate ecology and relies on robust methods. While distance sampling theory provides a robust framework for estimating animal abundance, implementing a constrained, non-systematic transect design could bias density estimates. Here, we assessed potential bias associated with line distance sampling surveys along roads based on a case study with olive baboons (Papio anubis) in Lake Manyara National Park (Tanzania). This was achieved by comparing density estimates of olive baboons derived from road transect surveys with density estimates derived from estimating the maximum number of social groups (via sleeping site counts) and multiplying this metric with the estimated average size of social groups. From 2011 to 2019, we counted olive baboons along road transects, estimated survey-specific densities in a distance sampling framework, and assessed temporal population trends. Based on the fitted half-normal detection function, the mean density was 132.5 baboons km-2 (95% CI: 110.4–159.2), however, detection models did not fit well due to heaping of sightings on and near the transects. Density estimates were associated with relatively wide confidence intervals that were mostly caused by encounter rate variance. Based on a generalized additive model, baboon densities were greater during the rainy seasons compared to the dry seasons but did not show marked annual trends. Compared to estimates derived from the alternative method (sleeping site survey), distance sampling along road transects overestimated the abundance of baboons more than threefold. Possibly, this overestimation was caused by the preferred use of roads by baboons. While being a frequently used technique (due to its relative ease of implementation compared to spatially randomized survey techniques), inferring population density of baboons (and possibly other species) based on road transects should be treated with caution. Beyond these methodological concerns and considering only the most conservative estimates, baboon densities in LMNP are among the highest across their geographic distribution range.
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Manigandan, S., H. Byju, and P. Kannan. "Assessing the accuracy of population estimation methods for vulture populations: a case study from the Mudumalai Tiger Reserve, Tamil Nadu, India." Environmental and Experimental Biology 21, no. 2 (2023): 45–52. http://dx.doi.org/10.22364/eeb.21.06.
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Two resident and two local migratory vulture species are reported in the Mudumalai Tiger Reserve of the Nilgiri Biosphere Reserve. The early population estimates from the region are either scanty or crude. Vulture population estimation was performed using three different methods based on their breeding seasons and regional movements between 2019 and 2021. Road transect counts, nest counts, and carcass monitoring counts were used for population assessments. The road transect survey and nest site counting during the breeding season were conducted in all three years, while carcass monitoring was done in 2019 – 2020. For population estimation, three nest site colony counts were conducted for the resident Gyps bengalensis and for Gyps indicus. The other two methods, carcass monitoring and the road transect survey, were used for all four focal vulture species of the Mudumalai Tiger Reserve – Gyps bengalensis, Gyps indicus, Neophron percnopterus and Sarcogyps calvus. Significant variation in vulture population count was observed with different assessment methods.
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Rojas, Vanessa G., Susan C. Loeb, and Joy M. O'Keefe. "Applying mobile acoustic surveys to model bat habitat use across sinuous routes." Wildlife Society Bulletin 46, no. 4 (2022): e1353. https://doi.org/10.5281/zenodo.13432128.
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(Uploaded by Plazi for the Bat Literature Project) Mobile acoustic surveys allow estimates of overall bat activity, relative abundance, and species richness across large areas. Protocols for estimating relative abundance recommend using non‐sinuous routes to ensure individual bats are only recorded once. We conducted mobile acoustic surveys along 12 sinuous routes in the mountainous terrain of northeastern Tennessee. Our objectives were to 1) determine if more calls were recorded in sinuous segments of mobile survey routes, thus violating assumptions of mobile surveys, and 2) analyze mobile transect data to assess bat habitat use. To test for effects of road sinuosity, we divided transects into ~1.6‐km segments, calculated a sinuosity value, and summed the number of identified call files recorded for each segment. Using generalized linear models, we determined sinuosity did not affect the number of identified acoustic files. We assessed habitat use for 3 bat phonic groups (Low, Mid, Myotis), comparing 10 models with temporal detection and spatial occupancy covariates. Date were informative for all phonic groups. Low and midfrequency bats were more likely to be detected on later survey dates within the summer, whereas Myotis bats had a higher probability of detection earlier within the season. As proportion of agriculture around the transect segment increased, probability of use by low‐frequency bats decreased. The proportion of forest surrounding the transect segment had a positive effect on use by Myotis bats. No environmental covariates were informative regarding mid‐frequency bats.
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Rojas, Vanessa G., Susan C. Loeb, and Joy M. O'Keefe. "Applying mobile acoustic surveys to model bat habitat use across sinuous routes." Wildlife Society Bulletin 46, no. 4 (2022): e1353. https://doi.org/10.5281/zenodo.13432128.
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(Uploaded by Plazi for the Bat Literature Project) Mobile acoustic surveys allow estimates of overall bat activity, relative abundance, and species richness across large areas. Protocols for estimating relative abundance recommend using non‐sinuous routes to ensure individual bats are only recorded once. We conducted mobile acoustic surveys along 12 sinuous routes in the mountainous terrain of northeastern Tennessee. Our objectives were to 1) determine if more calls were recorded in sinuous segments of mobile survey routes, thus violating assumptions of mobile surveys, and 2) analyze mobile transect data to assess bat habitat use. To test for effects of road sinuosity, we divided transects into ~1.6‐km segments, calculated a sinuosity value, and summed the number of identified call files recorded for each segment. Using generalized linear models, we determined sinuosity did not affect the number of identified acoustic files. We assessed habitat use for 3 bat phonic groups (Low, Mid, Myotis), comparing 10 models with temporal detection and spatial occupancy covariates. Date were informative for all phonic groups. Low and midfrequency bats were more likely to be detected on later survey dates within the summer, whereas Myotis bats had a higher probability of detection earlier within the season. As proportion of agriculture around the transect segment increased, probability of use by low‐frequency bats decreased. The proportion of forest surrounding the transect segment had a positive effect on use by Myotis bats. No environmental covariates were informative regarding mid‐frequency bats.
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Rojas, Vanessa G., Susan C. Loeb, and Joy M. O'Keefe. "Applying mobile acoustic surveys to model bat habitat use across sinuous routes." Wildlife Society Bulletin 46, no. 4 (2022): e1353. https://doi.org/10.5281/zenodo.13432128.
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(Uploaded by Plazi for the Bat Literature Project) Mobile acoustic surveys allow estimates of overall bat activity, relative abundance, and species richness across large areas. Protocols for estimating relative abundance recommend using non‐sinuous routes to ensure individual bats are only recorded once. We conducted mobile acoustic surveys along 12 sinuous routes in the mountainous terrain of northeastern Tennessee. Our objectives were to 1) determine if more calls were recorded in sinuous segments of mobile survey routes, thus violating assumptions of mobile surveys, and 2) analyze mobile transect data to assess bat habitat use. To test for effects of road sinuosity, we divided transects into ~1.6‐km segments, calculated a sinuosity value, and summed the number of identified call files recorded for each segment. Using generalized linear models, we determined sinuosity did not affect the number of identified acoustic files. We assessed habitat use for 3 bat phonic groups (Low, Mid, Myotis), comparing 10 models with temporal detection and spatial occupancy covariates. Date were informative for all phonic groups. Low and midfrequency bats were more likely to be detected on later survey dates within the summer, whereas Myotis bats had a higher probability of detection earlier within the season. As proportion of agriculture around the transect segment increased, probability of use by low‐frequency bats decreased. The proportion of forest surrounding the transect segment had a positive effect on use by Myotis bats. No environmental covariates were informative regarding mid‐frequency bats.
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Rojas, Vanessa G., Susan C. Loeb, and Joy M. O'Keefe. "Applying mobile acoustic surveys to model bat habitat use across sinuous routes." Wildlife Society Bulletin 46, no. 4 (2022): e1353. https://doi.org/10.5281/zenodo.13432128.
Full textAbstract:
(Uploaded by Plazi for the Bat Literature Project) Mobile acoustic surveys allow estimates of overall bat activity, relative abundance, and species richness across large areas. Protocols for estimating relative abundance recommend using non‐sinuous routes to ensure individual bats are only recorded once. We conducted mobile acoustic surveys along 12 sinuous routes in the mountainous terrain of northeastern Tennessee. Our objectives were to 1) determine if more calls were recorded in sinuous segments of mobile survey routes, thus violating assumptions of mobile surveys, and 2) analyze mobile transect data to assess bat habitat use. To test for effects of road sinuosity, we divided transects into ~1.6‐km segments, calculated a sinuosity value, and summed the number of identified call files recorded for each segment. Using generalized linear models, we determined sinuosity did not affect the number of identified acoustic files. We assessed habitat use for 3 bat phonic groups (Low, Mid, Myotis), comparing 10 models with temporal detection and spatial occupancy covariates. Date were informative for all phonic groups. Low and midfrequency bats were more likely to be detected on later survey dates within the summer, whereas Myotis bats had a higher probability of detection earlier within the season. As proportion of agriculture around the transect segment increased, probability of use by low‐frequency bats decreased. The proportion of forest surrounding the transect segment had a positive effect on use by Myotis bats. No environmental covariates were informative regarding mid‐frequency bats.
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Maxwell, Bruce D., Vickie Backus, Matthew G. Hohmann, et al. "Comparison of Transect-Based Standard and Adaptive Sampling Methods for Invasive Plant Species." Invasive Plant Science and Management 5, no. 2 (2012): 178–93. http://dx.doi.org/10.1614/ipsm-d-11-00022.1.
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AbstractEarly detection of an invading nonindigenous plant species (NIS) may be critical for efficient and effective management. Adaptive survey sampling methods may provide unbiased sampling for best estimates of distribution of rare and spatially clustered populations of plants in the early stages of invasion. However, there are few examples of these methods being used for nonnative plant surveys in which travelling distances away from an initial or source patch, or away from a road or trail, can be time consuming due to the topography and vegetation. Nor is there guidance as to which of the many adaptive methods would be most appropriate as a basis for invasive plant mapping and subsequent management. Here we used an empirical complete census of four invader species in early to middle stages of invasion in a management area to assess the effectiveness and efficiency of three nonadaptive methods, four adaptive cluster methods, and four adaptive web sampling methods that all originated from transects. The adaptive methods generally sampled more NIS-occupied cells and patches than standard transect approaches. Sampling along roads only was time-efficient and effective, but only for species with restricted distribution along the roads. When populations were more patchy and dispersed over the landscape the adaptive cluster starting at the road generally proved to be the most time-efficient and effective NIS detection method.
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Rydell, Jens, Marcus Elfström, Johan Eklöf, and Sonia Sánchez-Navarro. "Dramatic decline of northern bat Eptesicus nilssonii in Sweden over 30 years." Royal Society Open Science 7, no. 2 (2020): 191754. http://dx.doi.org/10.1098/rsos.191754.
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We monitored northern bat Eptesicus nilssonii (Keyserling & Blasius, 1839) acoustically along a 27 km road transect at weekly intervals in 1988, 1989 and 1990, and again in 2016 and 2017. The methodology of data collection and the transect were the same throughout, except that the insect-attracting mercury-vapour street-lights along parts of the road were replaced by sodium lights between the two survey periods. Counts along sections of the transect with and without street-lights were analysed separately. The frequency of bat encounters in unlit sections showed an average decline of 3.0% per year, corresponding to a reduction of 59% between 1988 and 2017. Sections with street-lights showed an 85% decline over the same period (6.3% per year). The decline represents a real reduction in the abundance of bats rather than an artefact of changed distribution of bats away from roads. Our study conforms with another long-term survey of the same species on the Baltic island of Gotland. Our results agree with predictions based on climate change models. They also indicate that the decline was caused directly by the disuse of the insect-attracting mercury-vapour street-lights, which may have resulted in lower availability of preferred prey (moths). In the 1980s, E. nilssonii was considered the most common bat in Sweden, but the subsequent decline would rather qualify it for vulnerable or endangered status in the national Red List of Threatened Species.
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DANLADI, YAKUBU PAPI, and TIJANI KWAPYIL JEFFREY. "THE EFFECTS OF ANTHROPOGENIC ACTIVITIES ON THE DISTRIBUTION OF A LATEX-PRODUCING PLANT (Calotropis procera Aiton) ALONG ROAD SIDES IN JOS AND IT'S ENVIRONS." GPH-International Journal of Agriculture and Research 04, no. 07 (2021): 15–26. https://doi.org/10.5281/zenodo.6859845.
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This study is carried out to investigate the effects of anthropogenic activities on the availability of Calotropis procera on the roadside in Jos. The line transect sampling technique was used to establish 10 plots with a diameter of 10 X 10 meters (100 m<sup>2</sup>) wide in each location and the total number of plants was enumerated. The frequency of occurrences, species richness, and diversity index was calculated using Shannon Weiner index methods. The results of the survey revealed a total number of plants at Old Airport Rayfield road indicated highest number of 133, followed by Low-Cost Miango road had 116, Rikkos Lamingo road showed 88, while Gada Biu Zaria road had 70 and Bukuru to Anguldi road had the least number of 43 plants. The frequency of occurrence at Old Airport Rayfield road and Low-Cost Miango road had the figure of 100 %, followed by Gada Biu Zaria road bypass with 90 % and Bukuru to Anguldi road and Rikkos Lamingo road had the occurrence of 70 % each, while species richness revealed a descending order of Old Airport Rayfield road> Low-Cost Miango road>Rikkos Lamingo road>Gada Biyui Zaria road>Bukuru Express to Anguldi. Anthropogenic activities are limited at roadsides due to the sloppy, slippery, and stony nature of the roads, thus latex-producing plants are indicators of the intense anthrogenic activities that have hampered the environmental development of Nigeria.
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Zamboni, Talía, Alicia Delgado, Ignacio Jiménez-Pérez, and Carlos De Angelo. "How many are there? Multiple-covariate distance sampling for monitoring pampas deer in Corrientes, Argentina." Wildlife Research 42, no. 4 (2015): 291. http://dx.doi.org/10.1071/wr14222.
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Context The pampas deer (Ozotoceros bezoarticus) is an endangered species in Argentina. Scarce information exists about one of the four last populations that survive in Corrientes province, where direct counts estimated a population of <500 individuals. Aims To evaluate the status of the pampas deer population in Corrientes by applying a standardised methodology and to develop methodological recommendations for future deer monitoring. Methods We conducted six population censuses between 2007 and 2010, using line transects placed on roads throughout 1200 km2 of grasslands in the Aguapey region, Corrientes, Argentina. From a moving vehicle, we counted every pampas deer group observed along transects. We used Distance 6.0 and its multiple-covariate distance sampling engine to estimate deer density, while exploring the potential effect of roads, habitat type, hour, season, observer experience and survey effort on deer occurrence and density estimation. Key results The occurrence of pampas deer was irrespective of transect location (minor or major road) but a greater number of animals was detected over transects in minor roads and in areas covered by grasslands with young pine plantations. We estimated a density of 1.17 individuals km–2 (s.e. = 0.52), and habitat type was the most important covariate for density estimation. We estimated a total population of 1495 deer (95% CI = 951–2351, CV = 23.27%) for the Aguapey region in Argentina. Conclusions Corrientes hosts one of the largest populations of pampas deer in Argentina, with ~1000 individuals. The fact that we estimated a larger population than did previous studies could be explained either by actual population growth during the past 10 years, or by the use of more exhaustive and sophisticated sampling design and data analysis. Implications Population surveys using covariate distance sampling on ground line transects can provide more realistic population estimates than do other simpler methods. Our population estimates and methods can be used as a baseline for future monitoring of this population, as long as factors such as sampling effort, type of roads for locating transects, and habitat type are considered in future analysis.
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Willson, John D., Shannon E. Pittman, Jeffrey C. Beane, and Tracey D. Tuberville. "A novel approach for estimating densities of secretive species from road-survey and spatial-movement data." Wildlife Research 45, no. 5 (2018): 446. http://dx.doi.org/10.1071/wr16175.
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Context Accurate estimates of population density are a critical component of effective wildlife conservation and management. However, many snake species are so secretive that their density cannot be determined using traditional methods such as capture–mark–recapture. Thus, the status of most terrestrial snake populations remains completely unknown. Aim We developed a novel simulation-based technique for estimating density of secretive snakes that combined behavioural observations of snake road-crossing behaviour (crossing speed), effort-corrected road-survey data, and simulations of spatial movement patterns derived from radio-telemetry, without relying on mark–recapture. Methods We used radio-telemetry data to parameterise individual-based movement models that estimate the frequency with which individual snakes cross roads and used information on survey vehicle speed and snake crossing speed to determine the probability of detecting a snake, given that it crosses the road transect during a survey. Snake encounter frequencies during systematic road surveys were then interpreted in light of detection probabilities and simulation model results to estimate snake densities and to assess various factors likely to affect abundance estimates. We demonstrated the broad applicability of this approach through a case study of the imperiled southern hognose snake (Heterodon simus) in the North Carolina (USA) Sandhills. Key results We estimated that H. simus occurs at average densities of 0.17 ha–1 in the North Carolina Sandhills and explored the sensitivity of this estimate to assumptions and variation in model parameters. Conclusions Our novel method allowed us to generate the first abundance estimates for H. simus. We found that H. simus exists at low densities relative to congeners and other mid-sized snake species, raising concern that this species may not only have declined in geographic range, but may also occur at low densities or be declining in their strongholds, such as the North Carolina Sandhills. Implications We present a framework for estimating density of species that have traditionally been considered too secretive to study at the population level. This method will greatly enhance our ability to study and manage a wide variety of snake species and could be applied to other secretive wildlife species that are most frequently encountered during road surveys.
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Dhiman, R., A. Thakur, S. Yadav, and P. K. Verma. "Status of Catamixis baccharoides Thomson (a critically endangered plant) in Western Himalayas." Journal of Environmental Biology 43, no. 6 (2022): 826–33. http://dx.doi.org/10.22438/jeb/43/6/mrn-4035.
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Aim: The aim of the study is to provide current conservation status of IUCN listed critically endangered species, Catamixis baccharoides, and to study the population density of species in three major locations: Biyasi, Rajaji National Park near Mansa devi in Uttarakhand and Mohand in Uttar Pradesh. Methodology: Two concurrent field surveys during April - May 2018 and March - May 2021, were conducted for population study of Catamixis baccharoides. Belt transect method was used for biomass evaluation of species at all three locations and sampling were done using transect path of 1000 m (20 m wide). Plants habit, morphology and phenology were described on the basis of field observation. Population density of the species in sample survey was determined and seeds were collected for germination test. Results: The population of plant in first survey 2018 was compared with 2021 survey and other previous survey conducted by other authors, and observed that there was sudden decease in plant density from 11 plants to zero in Biyasi location and the population was steady in Mohand (6 plants) and Mansa Devi (24 plants) Rajaji National Park Haridwar. Seeds seem to be recalcitrant in nature. Interpretation: Catamixis baccharoides, also known as “Vish-Patri”, an endemic monotypic shrub of Asteraceae family and is categorized in critically endangered category under IUCN. The population of this species is declining at an alarming rate from its natural habitat in Uttarakhand and Uttar Pradesh. In Biyasi location Uttarakhand, the population of species had vanished due to anthropogenic disturbances and ignorance during Char Dham road project and is decreasing rapidly in other locations. However, the medicinal and economical vantage of C. baccharoides is yet unexplored so, there is a need to take necessary steps to conserve the species in its natural habitat. Key words: Belt transect method, Conservation, Critically endangered, Monotypic
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Karimi, Abdul Ghani, Reinhard Michael Fritsch, Mustafa Hassani, and Chun-Lei Xiang. "Baseline Survey of Plant Species Along Salang Road in Afghanistan." Journal of Natural Science Review 2, no. 3 (2024): 17–28. http://dx.doi.org/10.62810/jnsr.v2i3.86.
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The Salang Road, a critical transportation corridor, serves as a vital link connecting the northern and southern parts of Afghanistan. In response to the government's decision to upgrade this road, assessing and documenting the plant species in the region is crucial. This study was conducted to catalog the plant species along the Salang Road, aiming to establish a comprehensive understanding of the area's botanical diversity. Plants were recorded using the quadrate sampling method at 35 sampling points. A transect line was set up at each sampling point, 5 quadrats were established along each line, and the occurrence of plants within the quadrat frame was recorded. Quadrat sizes, determined using the minimal area method, were 10×10 m for trees, 2×5 m for shrubs, and 1 m2 for herbs. Plants were identified with the help of literature and by comparing with the deposited specimen of Kabul University Faculty of Sciences Herbarium (KUFS). Data were analyzed using Microsoft Excel. 135 diverse species, including trees, shrubs, and herbs, representing various ecological niches were documented. These species belong to 46 plant families, and the most abundant ones were Asteraceae, Apiaceae, Rosaceae, Lamiaceae, Fabaceae, and Polygonaceae. The survey additionally examined road construction's impact on plant species' distribution and diversity. The survey provides valuable insights into the Salang corridor area's botanical diversity and ecological significance, serving as a foundational dataset for future environmental conservation and land management efforts. The information obtained from this study can support qualified decision-making and sustainable development practices in the region.
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Kamboj, Nitin, Ritesh Kumar, and Ravinder Singh Aswal. "Impact assesments of road develoment project on flora and fauna recorded from Narshan to Dehradun (Uttarakhand) India." Environment Conservation Journal 14, no. 1&2 (2013): 81–86. http://dx.doi.org/10.36953/ecj.2013.141214.
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The present study includes impact assessment of road development project on flora and fauna that has been recorded from Narsan to Dehradun Uttarakhand, India. Study includes the survey of existing green plants on the both side of National Highway from Narshan to Dehradun and Identification of different species and assessment of socio-economic importance of green plants. The methodological approach was divided into four main steps: flora and fauna loss impact assessment, mitigation, monitoring and recommendations. At the beginning of the study a preliminary survey was conducted in the study area for research design and the study was includes key information interviews and elderly and knowledgeable people, group discussion and map and transect walks. The total length of highway road in Uttarakhand is 110 km within two districts Haridwar and Dehradun. The major impact of road widening network was on flora and fauna that involves the removal of trees and destruction of animal’s habitat. As a result about 19934 trees are required to be cut for the proposed project on the left side and the right side due to the proposed widening. This study would provide integrated approaches to mitigate and manage to achieve sustainable road development project in India or abroad.
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CHAUDHARY, ANAND, TULSI RAM SUBEDI, JEET BAHADUR GIRI, et al. "Population trends of Critically Endangered Gyps vultures in the lowlands of Nepal." Bird Conservation International 22, no. 3 (2011): 270–78. http://dx.doi.org/10.1017/s0959270911000426.
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SummaryThree species of resident Gyps vulture are threatened with extinction in South Asia due to the contamination of domestic ungulate carcasses with the drug diclofenac. Observed rates of population decrease are among the highest recorded for any bird species, leading to total declines in excess of 99.9% for the Oriental White-backed Vulture Gyps bengalensis in India between 1992 and 2007. Vultures have declined in Nepal, but quantitative information on the rate and scale of decreases is unavailable. Road transect surveys for vultures, following the same route, methodology and timing, were undertaken in lowland areas of Nepal for seven years from 2002 to 2011. The seven survey transects followed Nepal’s East-West highway and covered 1,010 km in three years of the survey, and 638 km in the remaining four years. Slender-billed Vultures G. tenuirostris were very scarce, with a maximum of five individuals in 2002 and none recorded in 2010 and 2011. Oriental White-backed Vultures were most commonly recorded, but decreased from 205 to 68 birds over the survey period, with an estimated annual rate of decline of 14% a year. If population decreases commenced in Nepal in the same year as in India, then White-backed Vultures in Nepal have declined by 91% since the mid-1990s. Few resident Gyps vultures remained in Eastern and Central regions of Nepal, with just one, nine and six birds recorded in the three surveys that covered these regions. The majority of threatened Gyps vultures in lowland Nepal are now found in Western and Mid Western regions, where conservation efforts have been focused in the last six years. Removing veterinary diclofenac from across the country and continuing to manage effective “vulture safe zones” are essential to conserve Nepal’s remaining vulture populations.
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Budhathoki, Sital, Jagan Nath Adhikari, Binod Bhattarai, Dipendra Adhikari, and Bishnu Prasad Bhattarai. "Diversity and habitat associations of non-volant small mammals in forest patches of Kathmandu Valley, Nepal." Nepalese Journal of Zoology 7, no. 1 (2023): 26–35. http://dx.doi.org/10.3126/njz.v7i1.56308.
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Forest patches in urban areas can have the potential to provide shelter, resources, and breeding space for small mammals. This study aimed to explore the diversity, abundance, and habitat associations of non-volant small mammals in forest patches of Kathmandu Valley. Three sites were selected for the study: Ranibari Community Forest, Swayambhunath Hillock, and Coronation Garden of Tribhuvan University. The roost survey, line transect survey and direct observation methods were used for the study. The field survey was conducted in June–July 2019. In those selected sites, 250 m transects were laid and 25 live traps (Local, Sherman, and Tube) were set for capturing small mammals. Trapped individuals were measured, marked, and released at the site. From a survey of 600 trap nights, 61 individuals representing six species, four families and three orders were identified. Asian house shrew (Suncus murinus) was the most dominant species. Abundance of small mammals was higher in Ranibari Community Forest whereas Coronation Garden had the lowest abundance of non-volant small mammals. Small mammal distribution pattern was clumped in study areas owing to the uneven distribution of resources in the natural environment. Species response to five environmental parameters (distance to settlement, road, water, open canopy and closed canopy) showed significant relation in Ranibari Community Forest (F=2.446, P=0.018) and Coronation Garden (F=2.75 P=0.05), whereas it was insignificant in Swayambhunath Hillock (F=1.60 P=0.17). These results suggested that diversity, distribution, and abundance of small mammals in urban forest patches are influenced by habitat types and environmental parameters.
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Jr, Genaro F. Alderite, and Rex B. Ventura. "Rapid Assessment of Riparian Vegetation at Calyawan River, Barangay Andap, Municipality of New Bataan, Davao de Oro Province, Philippines." Annual Research & Review in Biology 39, no. 9 (2024): 159–67. http://dx.doi.org/10.9734/arrb/2024/v39i92130.
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Aims: The aim of this study was to examine the vegetation found along the riverbanks of the Calyawan River in Barangay Andap, Municipality of New Bataan, Province of Davao de Oro, Philippines using the transect walk method. The goals were to determine the variety and abundance of the flora along the riverbank, evaluate the conservation status of the discovered plant species, and suggest measures for safeguarding and preserving the riparian environment. Study Design: The study employed a transect walk method to carry out an initial survey of the riparian vegetation. A 1-kilometer transect was conducted along the riverbanks of the Calyawan River to gather qualitative and quantiatative measurements of plant diversity. The evaluation took place on December 20, 2022. This approach facilitated a quick and systematic examination of the vegetation along the riverbanks. Place and Duration: The study was carried out on the riverbanks of the Calyawan River in Barangay Andap, Municipality of New Bataan, Province of Davao de Oro. The fieldwork was conducted on December 20, 2022. The region can be reached by using the Compostela-Montevista-Mati Boundary Road. Methodology: The transect walk approach was employed to record the riparian flora during the survey. Plant species were identified and photographed, but no tangible plant specimens were collected. The obtained data encompassed the identification of fern and angiosperm taxa and families encountered along the transect. The conservation status assessments were conducted using the pre-existing classifications of the species. Results: A rapid assessment revealed the presence of 49 distinct genera of ferns and angiosperm plants belonging to 30 different families along the transect. Out of these, 74% of the riparian plant genera that were identified were found to be endemic to the region. The assessment of the riparian plants' conservation status indicated that 37% were classed as vulnerable, 30% as least concern, 22% as other threatened species, 10% as endangered, and 1% were not categorized. Although the sample time was short, these findings emphasize the abundance and importance of the riparian flora in terms of conservation. Conclusion: The initial study conducted along the riverbanks of Calyawan River indicated a notable variety of plants that grow along the river, with a large number of species that are unique to that area. Many identified plants have a conservation status that emphasizes the necessity for heightened sampling efforts and monitoring in order to gain a more comprehensive understanding of and safeguard this rich ecosystem. Considering the clear human-induced stresses on the forest fragments in the region, it is advisable to enhance and broaden conservation efforts in order to protect the riparian vegetation and guarantee its ongoing existence.
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Habe, Manuela. "Leading the way – presence of brown bear Ursus arctos, lynx Lynx lynx and grey wolf Canis lupus underlines the integrity and corridor function of the upper Neretva Valley in Bosnia and Herzegovina." Natura Sloveniae 25, no. 3 (2023): 201–11. http://dx.doi.org/10.14720/ns.25.3.201-211.
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Despite its connecting character to the Sutjeska National Park in the North-East, the course of the upper Neretva (Ulog and Borač valley) in Bosnia and Herzegovina (BiH), has to date not been an area of focus for carnivore research. With the aim of contributing to an improved understanding of the present distribution of large and endangered carnivores in this area, a field survey was conducted during the Neretva Science Week 2022. Opportunistic data collection was carried out along a predefined road transect (20 km) and six line transects (13 km) tracked by foot. Additionally, reports of mammal signs for six corresponding research sites along the Neretva were registered. Altogether, at least 15 mammal species could be distinguished. From the identified carnivores, four are listed in Annex II of the Habitats Directive. Furthermore, the signs of lynx presence, in addition to brown bear and grey wolf, highlight the connectivity value of the upper Neretva in its current state. Based on information from local practitioners, the main threats to large carnivores are hunting pressure and a negative perception as competitors. A likely decline in habitat quality and fragmentation, due to the planned hydropower plants expansion and logging activities, exacerbate these threats. Consequently, further systematic monitoring is recommended to assess the possible impact of human driven environmental changes.
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Istiadi, Yossa, Rita Retnowati, Agus Setya Pranowo, Marningot Tua Natalis Situmorang, and Try Junanto. "The Modelling Studies of Ecological Corridor Management of The Gunung Halimun Salak National Park, West Java, Indonesia." IJIS Edu : Indonesian Journal of Integrated Science Education 6, no. 1 (2024): 78. http://dx.doi.org/10.29300/ijisedu.v6i1.2391.
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This research aims to study the design of the ecological corridor management pattern of Gunung Halimun Salak National Park (TNGHS) through the identification of population and distribution of conservation species, edge effect of road access within the corridor, preservation mitigation, status of non-conservation species, and assessment of land-use-based ecotourism. The methods used include Belt transect, hypothetical transect, Intensive Point Account (IPA), and descriptive survey techniques. The research was conducted from September to December 2023. The results showed that the population density of Javan Gibbon was 0.114 indv/ha, Surili was 0.024 indv/ha, which is very low compared to the population density of TNGHS, 26 non-conservation bird species, and 1 endemic species, the Javan Gibbon. The edge effect is caused by the frequency of vehicles passing through the corridor. The hypothetical transect shows that the land use allocation for tea plantations is the target of ecotourism, and agricultural land use supports the product. The model design emphasizes the creation of protection zones for primates and Javan Eagles in terms of mobilization and migration, mitigation of vehicle crossings during the day, as well as the initiation of ecotourism based on non-conservation species and landscape characteristics. In conclusion, the ecological corridor management modeling includes accommodating the protection of endemic and rare animals, monitoring non-conservation bird species, conservation mitigation through vehicle frequency control, limited ecotourism development with a natural orientation, and agricultural products. Scientifically the contribution of this research is to explain the implications of island geography theory in the sustainability of endemic species in metapopulations to avoid genetic flow deviations.
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Jakobsberg, Grady O., Walter D. Mooney, and Jacqueline Rangel-Sanchez. "Assessment of an inexpensive trap design and survey method for vespine wasps (Hymenoptera, Vespidae, Vespinae)." Journal of Hymenoptera Research 89 (February 28, 2022): 171–82. https://doi.org/10.3897/jhr.89.80284.
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The introduction of the predatory Giant Asian Hornet, Vespa mandarinia Smith, to North America in 2019 has motivated efforts to create early detection systems for this and other non-native social wasp species (Hymenoptera, Vespidae). Various trap and bait combinations have been used for this purpose, most of which require assembly and materials that are costly, reducing their usefulness in large-scale survey systems. This study tests an inexpensive and efficient trapping technique for detecting or surveying vespine wasps. Traps were made from reused plastic bottles containing a brown sugar and water bait. They were deployed at heights ranging from 0–6 m above ground in several configurations. Captures for traps suspended 1 m or greater above ground were, on average, nine times higher than the catch of ground-level traps. A rapid trap deployment method for large geographic areas was created, which captured seven different vespine wasp species along a 395 km east-west road transect from mountains to coastal plain in the Mid-Atlantic region of the United States. The trapping design and survey methodology described below is inexpensive and fast and could be used by land managers or citizen scientists to detect V. mandarinia, other exotic vespine, or conducted on a large-scale vespine diversity survey.
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Lisá, Lenka, Pavel Vařeka, Kadicha Iskenderovna Tashbayeva, et al. "In the Footsteps of the Silk Road: Czech-Kyrgyz Geo-environmental Project." Interdisciplinaria Archaeologica Natural Sciences in Archaeology XV, no. 1 (2024): 109–22. http://dx.doi.org/10.24916/iansa.2024.1.8.
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Kyrgyzstan can be represented, geomorphologically-speaking, by a transect between the Fergana lowlands and the Tien Shan highlands and is an outstanding area for the study of paleoclimatic conditions relating to climatic changes. These changes have been crucial for the behaviour of past cultures in this area, especially due to the presence of the Silk Road. A Czech environmental team, covering geology, geomorphology, pedology, paleoecology, archaeobotany, malacology, osteology and many other disciplines, has been following up previous survey fieldwork undertaken in this area. Since 2021, the expeditions in the south-eastern Kyrgyzstan (Osh Region) have been aiming at the structure and settlement pattern development in the contact zone between the fertile Fergana basin and the steppe environment at the foothills of the Pamir-Alai and Tian-Shan Mountains, from prehistory until the present, including the material testimony of life on the ancient and medieval Silk Road. This work is a part of an agreement between the University of West Bohemia in Pilsen, the Osh State University and the Institute of History, Archaeology and Ethnology named after B. Dzamgyrchinov of the National Academy of Sciences of the Kyrgyz Republic. One of the major challenges of the ongoing geoarchaeological and palaeoecological research is to link climate changes and changes forced by human action with the transformation of settlement and landscape patterns.
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Edmondson, Vikki, James Martin, Owen Ardill, Michael Lim, Malal Kane, and John Woodward. "Seasonal Signals Observed in Non-Contact Long-Term Road Texture Measurements." Coatings 11, no. 6 (2021): 735. http://dx.doi.org/10.3390/coatings11060735.
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Texture is required on road pavements for safe vehicle braking and manoeuvres. This paper provides a unique analysis of long-term texture obtained using traffic speed condition survey (TRACS) data from 14 sites, located along a north to south transect spanning the longest highway in the UK. A total of 19 years of sensor measured texture depth (SMTD) data have been analyzed using spatial filtering techniques and compared with meteorological and traffic datasets. The results for hot rolled asphalt (HRA) surfaces reveal that changes to SMTD follow a linearly increasing trend with time. The “rate of change” is influenced by the order of magnitude of annual average daily traffic (AADT), when factored for the percentage of heavy goods vehicles. This linear trend is disrupted by environmental parameters, such as rainfall events and seasonal conditioning. In the summer, this signal is evident as a transient peak in the “rate of change” of texture greater than 0.04 mm, and in the winter as a reduction. The transient changes in texture corresponded to above average rainfall occurring in the week prior to SMTD measurement. The signal observed demonstrates an inverse pattern to the classically understood seasonal variation of skid resistance in the UK, where values are low in the summer and high in the winter. The findings demonstrate for the first time that texture measurements experience a seasonal signal, and provide compelling evidence pointing toward surface processes (such as polishing and the wetting and drying of surface contaminants) causing changes to texture that are affecting seasonal variation in skid resistance.
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Sushanto Gouda, Ht. Decemson, Abinash Parida, and G. S. Solanki. "Impact of shifting cultivation on mammalian diversity and distribution in fringe areas of Dampa tiger reserve, Mizoram, India." Environment Conservation Journal 21, no. 1&2 (2020): 103–15. http://dx.doi.org/10.36953/ecj.2020.211212.
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Shifting cultivation is a largely practiced agricultural technique in the north-eastern part of India. This has led the fragmentation of natural habitat for wildlife species. Impact of jhum cultivation on distribution of mammalian species was studied through transect survey for scat, camera trapping, and burrow counting. Barking deer (27%) and wild boar (24%) were most frequent visitors. Among the carnivores highest abundance (3-5 scat samples per jhum field) was recorded for leopard cat and Indian Palm civet. 2-5 years old abandoned jhum fields were recorded to be suitable habitat for movement of large herbivores. The frequency of scat decreased with age of the jhum >5 yrs. Road sides, trails and primary forest near the active jhum forest were actively visited by clouded leopard. The encounter rate for active and old burrows of rodents were highest in 1-2 years old/ recently abandoned jhum fields with a rate of 3.56 km2 and 2.68 km2 respectively. Camera trapping also resulted in 36 images of different animal species. Increased spatial heterogeneity promotes mammalian distribution.
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Thakur, Chandrakala, and Raghu Ram Parajuli. "Documentation of Wild Decorative Plants of Tribhuvan Highway in Makawanpur District, Nepal." Journal of Plant Resources 22, no. 1 (2024): 30–42. http://dx.doi.org/10.3126/bdpr.v22i1.68291.
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The present study highlights the exploration of wild decorative flowering plants which were documented on the roadside of the Tribhuvan highway from Hetauda to Tistung. This study area consists of tropical, sub-tropical and temperate vegetation types. This study was carried out during the year 2021-2023 and several field visits were performed. Plants were collected from the 17 transect line starting from Hetauda to Tistung Botanical Garden, Tistung. Each transect line was 200 meters in length measuring from the center of the road to 100 m left and 100 m right sides of the Tribhuvan Highway. From this survey altogether 120 species of wild ornamental plants belonging to 89 genera and 47 families were recorded. The most dominant family in terms of species richness was Orchidaceae having 30 species, followed by Fabaceae with 13 species. In terms of genera, Dendrobium and Coelogyne were the most dominant genera having seven species in each. Similarly, in analysis based on life form, the herb category was largest containing 61 species, followed by shrub with 31 species. Climber and tree consisted of 16 and 12 species respectively. The result also depicted that the diversity along the Tribhuvan Highway (Hetauda to Tistung) had an abundance of wild ornamental plants which comprises a wide range of diversity in terms of taxa, habit and life forms. This study suggests that this research work will be helpful for students, researchers and people who keep an interest in the gardening of indoor plants and outdoor landscape practices. Furthermore, in order to protect, conserve and perpetuate these plants, the florists, horticulturists, nurserymen and concern authorities are advised to introduce some potential native wild ornamental plants for the domestication.
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Harding, Elaine K., and Shirin Gomez. "Positive edge effects for arboreal marsupials: an assessment of potential mechanisms." Wildlife Research 33, no. 2 (2006): 121. http://dx.doi.org/10.1071/wr04059.
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In this study we examined the potential for positive edge effects on folivorous arboreal marsupials inhabiting upland rainforest in the Wet Tropics region of far north Queensland, Australia. We predicted that the folivores should have increased densities at edges relative to interior forest 90 m from the edge owing to the following causal factors, either separately or in combination: (a) increased foliar biomass, measured as vertical foliage density; and/or (b) increased abundance of preferred food trees. To test these hypotheses, we conducted surveys of the lemuroid ringtail possum (Hemibelideus lemuroides), the green ringtail possum (Pseudochirops archeri), the Herbert River ringtail possum (Pseudochirulus herbertensis) and the coppery brushtail possum (Trichosurus vulpecula johnstonii) at two remnant rainforest sites with ‘hard’ edges such as roads or pasture. Because arboreal species are often difficult to survey accurately within forests, we utilised pellet counts as an index of the population and compared this to the common survey technique of night spotlighting. Our results indicated that pellet counts, combined over all species, were positively and strongly correlated with spotlighting results. Using pellet counts as a relative index of arboreal folivore populations, we found that edge transects contained a higher abundance of all species combined than did interior transects. Further, total foliage density in the 10–30-m vertical transect was found to be significantly correlated with total pellet counts at edge transects. Total preferred tree species was not significantly different between edge and interior transects. From these results we propose that foliage density, as a surrogate for biomass, is a possible mechanism explaining the higher abundance of arboreal marsupials at the edges of these two highland rainforest sites in north Queensland.
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Barbosa, Raul Afonso Pommer, Brendo Barros de Souza, Jaina Rodrigues Evangelista, et al. "Parasitism by Amblyomma rotundatum Koch, 1844 (Acarina: Ixodidae) on Rhinella marina Linnaeus, 1758 (Anura Bufonidae) in the Amazon Forest: geographic expansion across Madeira River." Nature and Conservation 14, no. 3 (2021): 72–79. http://dx.doi.org/10.6008/cbpc2318-2881.2021.003.0006.
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Host-parasite interactions between ticks and wild species are important for examining the ecology and distribution of ticks, as well as the consequences of these interactions for hosts and diseases. Ticks have medical importance because they are vectors of microorganisms and pathogens, such as viruses, bacteria, and protozoa, that can be transmitted to humans and other animals, causing serious disease. Like other anuran species, Rhinella marina also harbors a wide variety of parasites. This occurs mainly because of its large body size and because it occupies terrestrial environments, but also because it has direct contact with aquatic environments (larval and reproductive stages), thus presenting several opportunities for parasitic infections. This work has as main objective to describe the occurrences of host-parasite interactions between the species Rhinella marina (Linnaeus, 1758) and Amblyomma rotundatum (Koch, 1844) geographically expanding their occurrence in the Amazon rainforest through the Madeira River. During a herpetofauna survey, the first individual of R. marina was observed at 08:37 PM on September 20, 2020. The location is near a transect within a primary forest. This individual was parasitized by a single tick identified as Amblyomma rotundatum. On a second expedition, a second individual of R. marina was observed at 11:38 PM on January 5, 2021. The location is rural road C-01 in the municipality of Porto Velho-RO, which passes within a primary forest and deforested private properties. This individual was parasitized by nine ticks identified as Amblyomma rotundatum. An important observation to be made is that the occurrences of A. rotundatum parasitizing R. marina are 57 km apart and cross an important geographical barrier, the Madeira River of the Amazon basin. This work geographically expands the occurrence of A. rotundatum parasitism on R. marina and describes the natural histories of this host-parasite interaction of these species.
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Lee, Tracy S., Kimberly Rondeau, Rob Schaufele, Anthony P. Clevenger, and Danah Duke. "Developing a correction factor to apply to animal–vehicle collision data for improved road mitigation measures." Wildlife Research 48, no. 6 (2021): 501. http://dx.doi.org/10.1071/wr20090.
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Abstract ContextRoad mitigation to reduce animal–vehicle collisions (AVCs) is usually based on analysis of road survey animal carcass data. This is used to identify road sections with high AVC clusters. Large mammals that are struck and die away from a road are not recorded nor considered in these analyses, reducing our understanding of the number of AVCs and the cost–benefit of road mitigation measures. AimsOur aim was to develop a method to calculate a correction factor for large mammal carcass data reported through road survey. This will improve our understanding of the magnitude and cost of AVCs. MethodCitizen scientists reported animal carcasses on walking surveys along transects parallel to the highway and reported observations using a smartphone application at three sites over a 5-year period. These data were compared with traditional road survey data. Key resultWe found that many large mammals involved in AVCs die away from the road and are, therefore, not reported in traditional road surveys. A correction factor of 2.8 for our region can be applied to road survey data to account for injury bias error in road survey carcass data. ConclusionsFor large mammals, AVCs based on road survey carcass data are underestimates. To improve information about AVCs where little is known, we recommend conducting similar research to identify a correction factor to conventionally collected road survey carcass data. ImplicationsIdentifying road mitigation sites by transportation agencies tends to focus on road sections with above-threshold AVC numbers and where cost–benefit analyses deem mitigation necessary. A correction factor improves AVC estimate accuracy, improving the identification of sites appropriate for mitigation, and, ultimately, benefitting people and wildlife by reducing risks of AVCs.
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De Souza, Julio, Geovane Ramires, Marcos Rezende, et al. "CONSPICUOUS ROADSIDE AVIFAUNA’S SEASONAL VARIATION IN ECOTONE AND WETLAND ENVIRONMENTS WITHIN THE PANTANAL’S AQUIDAUANA REGION." Ornitología Neotropical 30 (August 9, 2019): 141–49. http://dx.doi.org/10.58843/ornneo.v30i0.422.
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Abstract ∙ Transport by road is the main mechanism for integrating Brazil, but roads are drivers of land cover conversion, fragmentation, and direct mortality by wildlife-vehicle collisions. In Aquidauana, BR419 and MS170 are important unpaved roads into the rural Pantanal region, and improvement and paving has been planned for BR419, which may increase risks to local avifauna. The aim of this study was to assess the species composition and richness of conspicuous avifauna (defined as being easily quantifiable using roadside surveys), and their spatial and seasonal variation among two important roadways. One of the surveyed roadways accessing rural areas of the Aquidauana region of the Pantanal was scheduled for improvement and paving. Transects of 73 km long were sampled along both highways, six samples along each transect between February and May 2012, for a full sample effort of 103:06 hours. A total of 6888 individuals from 33 families and 93 species were observed in the transects combined, and 83 species were identified in each transect. Jaccard Similarity Index was 0.79, and we found a statistically significant difference (P < 0.05) among the bird communities between the highways. Species associated with freshwater environments were more abundant along and indicator species of MS170. That avifauna along MS170 varied temporally and species richness was strongly correlated with river discharge, while the same was not true with BR419. Species particularly vulnerable to wildlife-vehicle collisions, e.g., vultures (Coragyps atratus, C. aura) and Southern Caracara (Caracara plancus), were abundant along BR419. While mitigation measures for mammals, reptiles, and amphibians are common and effective, the vertical movement of most birds into the roadway presents a different challenge for which a technical solution may not currently exist. To protect species observed along the currently unpaved roadways of Pantanal’s Aquidauana region, following road improvement, speed limits should be calibrated to facilitate safe transportation for drivers and the continued existence of wild species. Resumo · Espécies de pássaros conspicuentes variação sazonal em ambientes de ecotone e pântano na região Aquidauana do Pantanal O transporte rodoviário é o principal mecanismo de integração do Brasil, mas as estradas são propulsoras da conversão, fragmentação e mortalidade direta da cobertura vegetal por colisões de veículos silvestres. Em Aquidauana, a BR419 e a MS170 são importantes estradas não pavimentadas para a região rural do Pantanal, melhorias e pavimentação foram planejadas para a BR419, o que pode aumentar os riscos para a avifauna local. O objetivo deste estudo foi avaliar a composição de espécies e a riqueza da avifauna conspícua (definido como sendo facilmente quantificável usando levantamentos de beira de estrada) e sua variação espacial e sazonal entre duas estradas importantes. Uma das estradas pesquisadas acessando áreas rurais da região de Aquidauana do Pantanal foi programada para melhorias e pavimentação. Transectos de 73 km de extensão foram amostrados ao longo das duas rodovias, seis amostras ao longo de cada transecto entre fevereiro e maio de 2012, para um esforço amostral completo de 103:06 horas. Um total de 6888 indivíduos de 33 famílias e 93 espécies foram observados nos transectos combinados, e 83 espécies foram identificadas em cada transecto. Índice de Similaridade de Jaccard foi de 0,79, e encontramos uma diferença estatisticamente significativa (P < 0,05) entre as comunidades de aves entre as rodovias. Espécies associadas a ambientes de água doce foram mais abundantes e espécies indicadoras da MS170. Essa avifauna ao longo da MS170 variou temporalmente e a riqueza de espécies foi fortemente correlacionada com a descarga do rio, enquanto o mesmo não ocorreu com a BR419. Espécies particularmente vulneráveis a colisões de veículos silvestres , por exemplo, abutres (Coragyps atratus, C. aura) e Caracará (Caracara plancus), foram abundantes ao longo da BR419. Embora as medidas de mitigação para mamíferos, répteis e anfíbios sejam comuns e eficazes, o movimento vertical da maioria das aves na pista apresenta um desafio diferente para o qual uma solução técnica pode não existir atualmente. Para proteger as espécies observadas ao longo das estradas atualmente não pavimentadas da região de Aquidauana, no Pantanal, seguindo a melhoria das estradas, os limites de velocidade devem ser calibrados para facilitar o transporte seguro dos motoristas e a existência contínua de espécies silvestres.
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Kluever, Bryan M., Eric M. Gese, and Steven J. Dempsey. "The influence of road characteristics and species on detection probabilities of carnivore faeces." Wildlife Research 42, no. 1 (2015): 75. http://dx.doi.org/10.1071/wr14244.
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Context Determining reliable estimates of carnivore population size and distributions are paramount for developing informed conservation and management plans. Traditionally, invasive sampling has been employed to monitor carnivores, but non-invasive sampling has the advantage of not needing to capture the animal and is generally less expensive. Faeces sampling is a common non-invasive sampling technique and future use is forecasted to increase due to the low costs and logistical ease of sampling, and more advanced techniques in landscape and conservation genetics. For many species, faeces sampling often occurs on or alongside roads. Despite the commonality of road-based faeces sampling, detectability issues are often not addressed. Aim We sought to test whether faeces detection probabilities varied by species – coyote (Canis latrans) versus kit fox (Vulpes macrotis) – and to test whether road characteristics influenced faeces detection probabilities. Methods We placed coyote and kit fox faeces along roads, quantified road characteristics, and then subsequently conducted ‘blind’ road-based faeces detection surveys in Utah during 2012 and 2013. Technicians that surveyed the faeces deposition transects had no knowledge of the locations of the placed faeces. Key results Faeces detection probabilities for kit foxes and coyotes were 45% and 74%, respectively; larger faeces originated from coyotes and were more readily detected. Misidentification of placed faeces was rare and did not differ by species. The width of survey roads and the composition of a road’s surface influenced detection probabilities. Conclusion We identified factors that can influence faeces detection probabilities. Not accounting for variable detection probabilities of different species or not accounting for or reducing road-based variables influencing faeces detection probabilities could hamper reliable counts of mammalian faeces, and could potentially reduce precision of population estimates derived from road-based faeces deposition surveys. Implications We recommend that wildlife researchers acknowledge and account for imperfect faeces detection probabilities during faecal sampling. Steps can be taken during study design to improve detection probabilities, and during the analysis phase to account for variable detection probabilities.
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Kitzes, Justin, Adina Merenlender, and R. Mark Brigham. "Large Roads Reduce Bat Activity across Multiple Species." PLoS ONE 9, no. 5 (2014): e96341. https://doi.org/10.5281/zenodo.13447765.
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(Uploaded by Plazi for the Bat Literature Project) Although the negative impacts of roads on many terrestrial vertebrate and bird populations are well documented, there have been few studies of the road ecology of bats. To examine the effects of large roads on bat populations, we used acoustic recorders to survey bat activity along ten 300 m transects bordering three large highways in northern California, applying a newly developed statistical classifier to identify recorded calls to the species level. Nightly counts of bat passes were analyzed with generalized linear mixed models to determine the relationship between bat activity and distance from a road. Total bat activity recorded at points adjacent to roads was found to be approximately one-half the level observed at 300 m. Statistically significant road effects were also found for the Brazilian free-tailed bat (Tadarida brasiliensis), big brown bat (Eptesicus fuscus), hoary bat (Lasiurus cinereus), and silver-haired bat (Lasionycteris noctivagans). The road effect was found to be temperature dependent, with hot days both increasing total activity at night and reducing the difference between activity levels near and far from roads. These results suggest that the environmental impacts of road construction may include degradation of bat habitat and that mitigation activities for this habitat loss may be necessary to protect bat populations.
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Kitzes, Justin, Adina Merenlender, and R. Mark Brigham. "Large Roads Reduce Bat Activity across Multiple Species." PLoS ONE 9, no. 5 (2014): e96341. https://doi.org/10.5281/zenodo.13447765.
Full textAbstract:
(Uploaded by Plazi for the Bat Literature Project) Although the negative impacts of roads on many terrestrial vertebrate and bird populations are well documented, there have been few studies of the road ecology of bats. To examine the effects of large roads on bat populations, we used acoustic recorders to survey bat activity along ten 300 m transects bordering three large highways in northern California, applying a newly developed statistical classifier to identify recorded calls to the species level. Nightly counts of bat passes were analyzed with generalized linear mixed models to determine the relationship between bat activity and distance from a road. Total bat activity recorded at points adjacent to roads was found to be approximately one-half the level observed at 300 m. Statistically significant road effects were also found for the Brazilian free-tailed bat (Tadarida brasiliensis), big brown bat (Eptesicus fuscus), hoary bat (Lasiurus cinereus), and silver-haired bat (Lasionycteris noctivagans). The road effect was found to be temperature dependent, with hot days both increasing total activity at night and reducing the difference between activity levels near and far from roads. These results suggest that the environmental impacts of road construction may include degradation of bat habitat and that mitigation activities for this habitat loss may be necessary to protect bat populations.
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Kitzes, Justin, Adina Merenlender, and R. Mark Brigham. "Large Roads Reduce Bat Activity across Multiple Species." PLoS ONE 9, no. 5 (2014): e96341. https://doi.org/10.5281/zenodo.13447765.
Full textAbstract:
(Uploaded by Plazi for the Bat Literature Project) Although the negative impacts of roads on many terrestrial vertebrate and bird populations are well documented, there have been few studies of the road ecology of bats. To examine the effects of large roads on bat populations, we used acoustic recorders to survey bat activity along ten 300 m transects bordering three large highways in northern California, applying a newly developed statistical classifier to identify recorded calls to the species level. Nightly counts of bat passes were analyzed with generalized linear mixed models to determine the relationship between bat activity and distance from a road. Total bat activity recorded at points adjacent to roads was found to be approximately one-half the level observed at 300 m. Statistically significant road effects were also found for the Brazilian free-tailed bat (Tadarida brasiliensis), big brown bat (Eptesicus fuscus), hoary bat (Lasiurus cinereus), and silver-haired bat (Lasionycteris noctivagans). The road effect was found to be temperature dependent, with hot days both increasing total activity at night and reducing the difference between activity levels near and far from roads. These results suggest that the environmental impacts of road construction may include degradation of bat habitat and that mitigation activities for this habitat loss may be necessary to protect bat populations.
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Kitzes, Justin, Adina Merenlender, and R. Mark Brigham. "Large Roads Reduce Bat Activity across Multiple Species." PLoS ONE 9, no. 5 (2014): e96341. https://doi.org/10.5281/zenodo.13447765.
Full textAbstract:
(Uploaded by Plazi for the Bat Literature Project) Although the negative impacts of roads on many terrestrial vertebrate and bird populations are well documented, there have been few studies of the road ecology of bats. To examine the effects of large roads on bat populations, we used acoustic recorders to survey bat activity along ten 300 m transects bordering three large highways in northern California, applying a newly developed statistical classifier to identify recorded calls to the species level. Nightly counts of bat passes were analyzed with generalized linear mixed models to determine the relationship between bat activity and distance from a road. Total bat activity recorded at points adjacent to roads was found to be approximately one-half the level observed at 300 m. Statistically significant road effects were also found for the Brazilian free-tailed bat (Tadarida brasiliensis), big brown bat (Eptesicus fuscus), hoary bat (Lasiurus cinereus), and silver-haired bat (Lasionycteris noctivagans). The road effect was found to be temperature dependent, with hot days both increasing total activity at night and reducing the difference between activity levels near and far from roads. These results suggest that the environmental impacts of road construction may include degradation of bat habitat and that mitigation activities for this habitat loss may be necessary to protect bat populations.
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Hayes, Ian F., and Ross L. Goldingay. "Use of fauna road-crossing structures in north-eastern New South Wales." Australian Mammalogy 31, no. 2 (2009): 89. http://dx.doi.org/10.1071/am09007.
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The vast network of roads around the world has had a significant effect on wildlife and ecosystems through habitat fragmentation, reduced dispersal and mortality by collision with vehicles. Road agencies worldwide now frequently install dedicated structures to facilitate the safe crossing of roads by wildlife. We conducted surveys to determine the use of dedicated wildlife overpasses and nearby underpasses at two locations on the Pacific Highway in north-eastern New South Wales. Road-kill surveys were conducted to provide some understanding of the species commonly killed and whether the rate of road-kill was lower at one location where crossing-structures were located. Use of the crossing-structures by wildlife was monitored with sand-transects. The most frequent users were macropods, bandicoots and rodents. Macropods made greater use of overpasses (n = 104 tracks) than underpasses (n = 36), whereas underpasses were used more by bandicoots (n = 87) and rodents (n = 82) than were overpasses (n = 28, n = 15, respectively). We identified 78 road-kills of 21 species on two sections of the Pacific Highway over a 7-week period. Bandicoots (n = 16) and macropods (n = 9) were the most frequently observed victims. The mortality of wildlife was lower along the highway section with the crossing-structures (0.04 road-kills km–1) than it was along the highway section without structures (0.15 road-kills km–1). The lack of replication precludes any firm conclusion that the crossing-structures reduced road mortality but the high level of use of the crossing-structures by species that were common victims of road-kill suggests an influence.
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Laxmi Narayana, B., V. Vasudeva Rao, M. Sandeep, G. Surender, and A. V. L. N. Ramaligeswara Rao. "A Preliminary Survey of House Sparrow (Passer domesticus) in Ramakrishna Beach Road, Vishakhapatnam (Vizag), Andhra Pradesh." International Letters of Natural Sciences 31 (January 2015): 1–6. http://dx.doi.org/10.18052/www.scipress.com/ilns.31.1.
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We studied the population records of House Sparrow Passer domesticus 16th to 20th December 2011 during winter in Ramakrishna Beach Road Vishakhapatnam town, Andhra Pradesh. The ecological density of House Sparrow was investigated using fixed width transects. A total of 189 House sparrows were recorded. The present study shows that a notable population of House Sparrow in Beach Road.
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Saraswati, Saraswati, Yubraj Bhusal, Andrew J. Trant, and Maria Strack. "Roads Impact Tree and Shrub Productivity in Adjacent Boreal Peatlands." Forests 11, no. 5 (2020): 594. http://dx.doi.org/10.3390/f11050594.
Full textAbstract:
Peatlands in the western boreal plains of Canada are important ecosystems as they store over two percent of global terrestrial carbon. However, in recent decades, many of these peatlands have been fragmented by access roads constructed for resource extraction and transportation, challenging their carbon storage potential. To investigate how roads have been impacting tree and shrub growth and productivity in these peatlands, this study was conducted in a forested bog and woody fen in Carmon Creek, Alberta, Canada. In 2017, vegetation surveys were conducted along 20 m transects that extended on both sides of the road with 4 m2 circular plots at 2, 6 and 20 m distance from the road and were followed by disc or core collection from woody stems. Within 20 m of the road at the bog site, we observed a shift towards significantly larger radial growth of trees in the downstream areas (t = 3.23, p = 0.006) where water table position was deeper, while at the fen site, radial growth of tall shrubs had little response to the road. Combining the effects of direct tree clearing and hydrology induced shifts in growth, aboveground net primary productivity (NPPag) post-road construction was reduced significantly in areas where vegetation was cleared during the road construction (i.e., upstream areas of the bog: t = 5.21, p < 0.0001 and downstream areas of the fen: t = 2.64, p = 0.07). Substantially lower NPPag around the road construction areas compared to reference areas shows tremendous loss of carbon sink potential of trees and shrubs after road construction through peatlands. Altogether, roads constructed through peatlands perpendicular to the water flow may shift long-term carbon sinks into sources of carbon, at least for the initial few years following road construction.
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Laxmi Narayana, B., V. Vasudeva Rao, M. Sandeep, G. Surender, and A. V. L. N. Ramaligeswara Rao. "A Preliminary Survey of House Sparrow (<i>Passer domesticus</i>) in Ramakrishna Beach Road, Vishakhapatnam (Vizag), Andhra Pradesh." International Letters of Natural Sciences 31 (January 4, 2015): 1–6. http://dx.doi.org/10.56431/p-6wfh93.
Full textAbstract:
We studied the population records of House Sparrow Passer domesticus 16th to 20th December 2011 during winter in Ramakrishna Beach Road Vishakhapatnam town, Andhra Pradesh. The ecological density of House Sparrow was investigated using fixed width transects. A total of 189 House sparrows were recorded. The present study shows that a notable population of House Sparrow in Beach Road.
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Hilário, Renato R., Flávio H. G. Rodrigues, Adriano G. Chiarello, and Ítalo Mourthé. "Can Roads Be Used as Transects for Primate Population Surveys." Folia Primatologica 83, no. 1 (2012): 47–55. http://dx.doi.org/10.1159/000339805.
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Khanal, Arjun. "Urban Bird Counting From Lothar to Tikauli Bufferzone Forest, Chitwan, Nepal." Shaheed Smriti Journal 13, no. 10 (2024): 116–25. https://doi.org/10.3126/shaheedsmriti.v13i10.76816.
Full textAbstract:
Urbanization results in habitat modification causing alteration in the assemblage of biological diversity. Bird diversity serves as a good ecological indicator; hence, this study examined the effects of urbanization on bird species counting and diversity in East-west highway from Lothar Khola to Tikauli Bufferzone Forest, Chitwan. Bird surveys were conducted during the spring season and pre-monsoon seasons of 2022 along fifteen transects each of 2 km length by positioning the point count stations at every 2 km interval on vehicle survey. A total of 3,147 birds of 63 species were observed from 28 families. Among the 63 species, 58 were residents and 5 were migratory. The associations of bird richness and abundance were found higher in forest area that covers almost 20% of the total surveyed transects. Number of nest were also recorded throughout the entire survey and majority of nest were of Baya weaber. Conversely, road under construction showed negative effects. In an urban setting, 100 nesting sites were recorded on electric pole, tree species and some on the residential houses. Thus, cities should focus on developing green city concept simultaneously with other developmental projects.
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Tomás, W. M., W. McShea, G. H. B. de Miranda, J. R. Moreira, G. Mourao, and P. A. L. Borges. "A survey of a pampas deer, Ozotoceros bezoarticus leucogaster (Arctiodactyla, Cervidae), population in the Pantanal wetland, Brazil, using the distance sampling technique." Animal Biodiversity and Conservation 24, no. 1 (2001): 101–6. https://doi.org/10.32800/abc.2001.24.0101.
Full textAbstract:
The pampas deer is an endangered South American species which occurs in open grasslands and savannas. This aim of this survey was to evaluate the use of the distance sampling technique to estimate densities of the species in the Pantanal wetland, as well as to analyze the applicability of the method for a monitoring program. The surveys were conducted on roads from vehicles and also on foot along 26 parallel transects in November 1999 and 2000 at Campo Dora ranch, south-central Pantanal, Brazil. Deer densities were estimated using the program DISTANCE, and the program MONITOR was used to run a power analysis to estimate the probability of detection of a decline in the population. The deer density estimated from vehicles, with data from both years, was 9.81±3.8 individual/km2, and 5.53±0.68 individuals/km2 from transects sampled on foot. The power analysis of these data revealed a monitoring program would require at least two surveys per year over seven years to obtain a 90% chance of detecting a 5% decline in the population. Our results also indicate surveys from roads are not recommended for pampas deer counts as the animals appear to keep a relatively safe distance from cars.
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Garbett, Rebecca, Marc Herremans, Glyn Maude, Richard P. Reading, and Arjun Amar. "Raptor population trends in northern Botswana: A re-survey of road transects after 20 years." Biological Conservation 224 (August 2018): 87–99. http://dx.doi.org/10.1016/j.biocon.2018.05.020.
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King, Clint, and Jesse M. Meik. "Factors Influencing Activity and Detection of Species in a Cross Timbers Snake Assemblage." Diversity 15, no. 9 (2023): 952. http://dx.doi.org/10.3390/d15090952.
Full textAbstract:
The Cross Timbers of North America is an ecotone between the eastern deciduous forests and central grasslands and exhibits a diverse composite snake fauna. Over a 3-yr period, we performed repeated nocturnal road surveys of snakes across three transects in Wise County, Texas, and evaluated species composition, relative abundances, vehicular mortality, detection probability, and the influence of environmental variables on snake activity. Sixteen taxa and 406 observations were recorded over 250 surveys, and the three most frequently encountered species had detection probabilities of approximately 0.20: Pantherophis obsoletus, Agkistrodon laticinctus, and Nerodia rhombifer. Only the two species of Agkistrodon present at our study area showed significant differences in count frequencies across the three transects. Covariate effects on overall snake activity were subtle, with barometric pressure, ordinal date, and ambient temperature better explaining variation in combined snake counts than humidity, wind speed, or lunar phase. Furthermore, peak snake activity corresponded closely to the timing of peak warm-season precipitation in the study area, suggesting that snake activity coincides with rainfall periodicity in the Cross Timbers region. However, results of site-occupancy models indicated that covariate effects were different across species, and that several common species did not show clear responses to any of the survey covariates.
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Russo-Petrick, Kelly M., and Karen V. Root. "Identifying factors across multiple scales that impact bat activity and species richness along roads in a fragmented landscape." Biodiversity and Conservation 32, no. 3 (2023): 1065–88. https://doi.org/10.5281/zenodo.13430212.
Full textAbstract:
(Uploaded by Plazi for the Bat Literature Project) Roads have variable impacts on wildlife, including bats. Bat habitat preferences along roads are dependent on spatial/temporal scale and species. This creates the need for habitat studies incorporating multiple scales and years. The objectives of this study were to determine habitat factors impacting bat activity and species richness along road transects at local and landscape scales and to identify areas of highest bat activity. Bat activity and richness was compared to local-scale field data and landscape-scale data measured in ArcGIS and FRAGSTATS. Hotspot analysis was conducted in ArcGIS to determine areas of highest bat activity. At the local scale, bat activity and/or species richness were positively associated with canopy height, clutter (percent obstruction by vegetation or other objects) at 0–3 m, humidity, natural habitat, canopy cover, months water present, and temperature, and were negatively associated with clutter at 3–6.5 m. At the landscape scale, activity and/or richness had positive associations with habitat heterogeneity, roads, open natural habitats, ponds, upland prairie, and overall forest cover, and had negative associations with conifers and cropland. High activity areas were consistent between years and clustered near protected areas. Low activity areas were typically located near agriculture. When managing bat habitat along roads, it would be advantageous to decrease mid-level clutter, vary habitat types, increase savanna cover, avoid excessive conifer or cropland cover, plant tall trees, and provide water sources. This study shows that combining acoustic road surveys with habitat analyses at multiple scales can be used to examine habitat factors influencing bat activity and species richness.
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Russo-Petrick, Kelly M., and Karen V. Root. "Identifying factors across multiple scales that impact bat activity and species richness along roads in a fragmented landscape." Biodiversity and Conservation 32, no. 3 (2023): 1065–88. https://doi.org/10.5281/zenodo.13430212.
Full textAbstract:
(Uploaded by Plazi for the Bat Literature Project) Roads have variable impacts on wildlife, including bats. Bat habitat preferences along roads are dependent on spatial/temporal scale and species. This creates the need for habitat studies incorporating multiple scales and years. The objectives of this study were to determine habitat factors impacting bat activity and species richness along road transects at local and landscape scales and to identify areas of highest bat activity. Bat activity and richness was compared to local-scale field data and landscape-scale data measured in ArcGIS and FRAGSTATS. Hotspot analysis was conducted in ArcGIS to determine areas of highest bat activity. At the local scale, bat activity and/or species richness were positively associated with canopy height, clutter (percent obstruction by vegetation or other objects) at 0–3 m, humidity, natural habitat, canopy cover, months water present, and temperature, and were negatively associated with clutter at 3–6.5 m. At the landscape scale, activity and/or richness had positive associations with habitat heterogeneity, roads, open natural habitats, ponds, upland prairie, and overall forest cover, and had negative associations with conifers and cropland. High activity areas were consistent between years and clustered near protected areas. Low activity areas were typically located near agriculture. When managing bat habitat along roads, it would be advantageous to decrease mid-level clutter, vary habitat types, increase savanna cover, avoid excessive conifer or cropland cover, plant tall trees, and provide water sources. This study shows that combining acoustic road surveys with habitat analyses at multiple scales can be used to examine habitat factors influencing bat activity and species richness.
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Russo-Petrick, Kelly M., and Karen V. Root. "Identifying factors across multiple scales that impact bat activity and species richness along roads in a fragmented landscape." Biodiversity and Conservation 32, no. 3 (2023): 1065–88. https://doi.org/10.5281/zenodo.13430212.
Full textAbstract:
(Uploaded by Plazi for the Bat Literature Project) Roads have variable impacts on wildlife, including bats. Bat habitat preferences along roads are dependent on spatial/temporal scale and species. This creates the need for habitat studies incorporating multiple scales and years. The objectives of this study were to determine habitat factors impacting bat activity and species richness along road transects at local and landscape scales and to identify areas of highest bat activity. Bat activity and richness was compared to local-scale field data and landscape-scale data measured in ArcGIS and FRAGSTATS. Hotspot analysis was conducted in ArcGIS to determine areas of highest bat activity. At the local scale, bat activity and/or species richness were positively associated with canopy height, clutter (percent obstruction by vegetation or other objects) at 0–3 m, humidity, natural habitat, canopy cover, months water present, and temperature, and were negatively associated with clutter at 3–6.5 m. At the landscape scale, activity and/or richness had positive associations with habitat heterogeneity, roads, open natural habitats, ponds, upland prairie, and overall forest cover, and had negative associations with conifers and cropland. High activity areas were consistent between years and clustered near protected areas. Low activity areas were typically located near agriculture. When managing bat habitat along roads, it would be advantageous to decrease mid-level clutter, vary habitat types, increase savanna cover, avoid excessive conifer or cropland cover, plant tall trees, and provide water sources. This study shows that combining acoustic road surveys with habitat analyses at multiple scales can be used to examine habitat factors influencing bat activity and species richness.
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Russo-Petrick, Kelly M., and Karen V. Root. "Identifying factors across multiple scales that impact bat activity and species richness along roads in a fragmented landscape." Biodiversity and Conservation 32, no. 3 (2023): 1065–88. https://doi.org/10.5281/zenodo.13430212.
Full textAbstract:
(Uploaded by Plazi for the Bat Literature Project) Roads have variable impacts on wildlife, including bats. Bat habitat preferences along roads are dependent on spatial/temporal scale and species. This creates the need for habitat studies incorporating multiple scales and years. The objectives of this study were to determine habitat factors impacting bat activity and species richness along road transects at local and landscape scales and to identify areas of highest bat activity. Bat activity and richness was compared to local-scale field data and landscape-scale data measured in ArcGIS and FRAGSTATS. Hotspot analysis was conducted in ArcGIS to determine areas of highest bat activity. At the local scale, bat activity and/or species richness were positively associated with canopy height, clutter (percent obstruction by vegetation or other objects) at 0–3 m, humidity, natural habitat, canopy cover, months water present, and temperature, and were negatively associated with clutter at 3–6.5 m. At the landscape scale, activity and/or richness had positive associations with habitat heterogeneity, roads, open natural habitats, ponds, upland prairie, and overall forest cover, and had negative associations with conifers and cropland. High activity areas were consistent between years and clustered near protected areas. Low activity areas were typically located near agriculture. When managing bat habitat along roads, it would be advantageous to decrease mid-level clutter, vary habitat types, increase savanna cover, avoid excessive conifer or cropland cover, plant tall trees, and provide water sources. This study shows that combining acoustic road surveys with habitat analyses at multiple scales can be used to examine habitat factors influencing bat activity and species richness.
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Tayebwa, Gilbert, Priscilla Nyadoi, Benson Turyasingura, Patrick Engoru, and Adalbert Aine-Omucunguzi. "Wildlife–Vehicle Collisions in South-Central Uganda: Implications for Biodiversity Conservation." Conservation 5, no. 2 (2025): 26. https://doi.org/10.3390/conservation5020026.
Full textAbstract:
Vehicle collisions with wild animals are a significant cause of wild animal mortality. This impacts their population and spatiotemporal distribution within the ecosystem. Data on the impact of road kills on wild animals, particularly in the south-central part of Uganda, are not present. This study aimed to investigate the number of species involved in road kills in South-Central Uganda and their spatial and temporal distribution within South-Central Uganda. Three transects, each 40 km in length, were surveyed. In both wet and dry seasons, surveys were conducted monthly in the morning and afternoon from November 2019 through April 2024. The findings showed that 161 wildlife–vehicle accidents were detected within a four-and-a-half-year period, with 178 animal species involved. These incidents belonged to 12 mammals, five reptiles, two amphibians, and 32 avian families. Our study adds to a better understanding of the impact of roads on wildlife in Africa and is an essential starting point regarding conservation efforts to mitigate these effects. It provides a first summary of species that are frequently found as roadkill in this area of south-central Uganda. This acts as a reference point for future studies.
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Laurance, William F., Barbara M. Croes, Nicaise Guissouegou, Ralph Buij, Marc Dethier, and Alfonso Alonso. "Impacts of Roads, Hunting, and Habitat Alteration on Nocturnal Mammals in African Rainforests." Conservation Biology 22, no. 3 (2008): 721–32. https://doi.org/10.5281/zenodo.13512735.
Full textAbstract:
(Uploaded by Plazi for the Bat Literature Project) Nocturnal mammals are poorly studied in Central Africa, a region experiencing dramatic increases in logging, roads, and hunting activity. In the rainforests of southern Gabon, we used spotlighting surveys to estimate abundances of nocturnal mammal species and guilds at varying distances from forest roads and between hunted and unhunted treatments (comparing a 130-km2 oil concession that was nearly free of hunting, with nearby areas outside the concession that had moderate hunting pressure). At each of 12 study sites that were evenly divided between hunted and unhunted areas, we established standardized 1-km transects along road verges and at 50, 300, and 600 m from the road. We then repeatedly surveyed mammals at each site during 2006. Hunting had few apparent effects on this assemblage. Nevertheless, the species richness and often the abundance of nocturnal primates, smaller ungulates, and carnivores were significantly depressed within approximately 30 m of roads. Scansorial rodents increased in abundance in hunted forests, possibly in response to habitat changes caused by logging or nearby swidden farming. In multiple-regression models many species and guilds were significantly influenced by forest-canopy and understory cover, both of which are altered by logging and by certain abiotic variables. In general, nocturnal species, many of which are arboreal or relatively small in size (<10 kg), were less strongly influenced by hunting and more strongly affected by human-induced changes in forest structure than were larger mammal species in our study area.
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Laurance, William F., Barbara M. Croes, Nicaise Guissouegou, Ralph Buij, Marc Dethier, and Alfonso Alonso. "Impacts of Roads, Hunting, and Habitat Alteration on Nocturnal Mammals in African Rainforests." Conservation Biology 22, no. 3 (2008): 721–32. https://doi.org/10.5281/zenodo.13512735.
Full textAbstract:
(Uploaded by Plazi for the Bat Literature Project) Nocturnal mammals are poorly studied in Central Africa, a region experiencing dramatic increases in logging, roads, and hunting activity. In the rainforests of southern Gabon, we used spotlighting surveys to estimate abundances of nocturnal mammal species and guilds at varying distances from forest roads and between hunted and unhunted treatments (comparing a 130-km2 oil concession that was nearly free of hunting, with nearby areas outside the concession that had moderate hunting pressure). At each of 12 study sites that were evenly divided between hunted and unhunted areas, we established standardized 1-km transects along road verges and at 50, 300, and 600 m from the road. We then repeatedly surveyed mammals at each site during 2006. Hunting had few apparent effects on this assemblage. Nevertheless, the species richness and often the abundance of nocturnal primates, smaller ungulates, and carnivores were significantly depressed within approximately 30 m of roads. Scansorial rodents increased in abundance in hunted forests, possibly in response to habitat changes caused by logging or nearby swidden farming. In multiple-regression models many species and guilds were significantly influenced by forest-canopy and understory cover, both of which are altered by logging and by certain abiotic variables. In general, nocturnal species, many of which are arboreal or relatively small in size (<10 kg), were less strongly influenced by hunting and more strongly affected by human-induced changes in forest structure than were larger mammal species in our study area.
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Laurance, William F., Barbara M. Croes, Nicaise Guissouegou, Ralph Buij, Marc Dethier, and Alfonso Alonso. "Impacts of Roads, Hunting, and Habitat Alteration on Nocturnal Mammals in African Rainforests." Conservation Biology 22, no. 3 (2008): 721–32. https://doi.org/10.5281/zenodo.13512735.
Full textAbstract:
(Uploaded by Plazi for the Bat Literature Project) Nocturnal mammals are poorly studied in Central Africa, a region experiencing dramatic increases in logging, roads, and hunting activity. In the rainforests of southern Gabon, we used spotlighting surveys to estimate abundances of nocturnal mammal species and guilds at varying distances from forest roads and between hunted and unhunted treatments (comparing a 130-km2 oil concession that was nearly free of hunting, with nearby areas outside the concession that had moderate hunting pressure). At each of 12 study sites that were evenly divided between hunted and unhunted areas, we established standardized 1-km transects along road verges and at 50, 300, and 600 m from the road. We then repeatedly surveyed mammals at each site during 2006. Hunting had few apparent effects on this assemblage. Nevertheless, the species richness and often the abundance of nocturnal primates, smaller ungulates, and carnivores were significantly depressed within approximately 30 m of roads. Scansorial rodents increased in abundance in hunted forests, possibly in response to habitat changes caused by logging or nearby swidden farming. In multiple-regression models many species and guilds were significantly influenced by forest-canopy and understory cover, both of which are altered by logging and by certain abiotic variables. In general, nocturnal species, many of which are arboreal or relatively small in size (<10 kg), were less strongly influenced by hunting and more strongly affected by human-induced changes in forest structure than were larger mammal species in our study area.