scholarly journals Comparison of point and roadside transect methods to evaluate the abundance and richness of diurnal raptors in the arid region of Rajasthan

PLoS ONE ◽  
2021 ◽  
Vol 16 (12) ◽  
pp. e0259805
Author(s):  
Govind Tiwari ◽  
Puneet Pandey ◽  
Rahul Kaul ◽  
Hang Lee ◽  
Randeep Singh
Keyword(s):  
Species Richness ◽  
Average Length ◽  
Survey Methods ◽  
Survey Method ◽  
Point Count ◽  
Point Counts ◽  
Significant Difference ◽  
Unidentified Species ◽  
Species Richness And Abundance ◽  
Point Count Method

Diurnal raptors show a wider distribution compared to other groups of birds including passerines, woodpeckers, and seriemas, but occur at lower-than-expected densities. Estimating the precise abundance is essential to achieve conservation goals but the methods used to estimate the populations of birds need to be appropriate to arrive at meaningful conclusions. We compared the two survey methods: roadside point count and strip transects, for estimating species richness and abundance of raptors in the arid landscape of Rajasthan. Roadside point counts and roadside strip transects were done on 50 transects between December 2019- February 2020 (with an average length of 20 km and a total distance of 3000 km) to assess the species richness and abundance of raptors. A total of 2954 observations of raptors belonging to 35 species were recorded using both methods. Mann Whitney U test result showed no significant difference in species richness and abundance estimates between both methods (p = 0.206). The point count method yielded a higher relative abundance of 2.79 individuals [10 km2]-1h-1 than the 1.90 individuals [10 km2]-1h-1 obtained during the strip transect. Also, the number of unidentified species were less for point counts. Extrapolation values indicated that both the methods do not differ much for the detection of unsampled species. The choice of survey method depends on the objectives of the study, but our results favor the use of point counts rather than strip transects to survey raptors in open habitats. The information generated from this study is expected to provide the most efficient method to study the abundance and distribution of raptors in similar landscapes.

scholarly journals Patterns of Species Richness and Abundance in Badingilo National Park in South Sudan

2019 ◽  
Vol 1 (1) ◽  
Author(s):  
Thomas Francis Lado ◽  
David Gwolo Phanuel Mogga ◽  
Richard Angelo Lado Benjamin
Keyword(s):  
Species Richness ◽  
National Park ◽  
Habitat Type ◽  
Bird Species ◽  
Abundant Species ◽  
Point Count ◽  
Number Of Species ◽  
Riverine Habitat ◽  
Species Richness And Abundance ◽  
Point Count Method

The study was carried out to determine patterns of birds’ species richness, alpha and beta diversities; and abundance in Badingilo national park using a 10 m fixed-radius point count method. A total of 2670 individuals were recorded from 182 points in the park. The highest expected number of species (Jack1 estimator) was observed in the Riverine habitat and least was in the Agriculture and Human settlement habitat type. The total number of species observed in the park was 63; however Jack1 estimator indicated that there were 68 species in the park. The majority of the birds observed during the study were resident species, few migratory and Palaearctic bird species. Few birds observed in the park were abundant. The most abundant species was the village weaver (381 individuals), and the rarest species were black-bellied bustard, barn owl, black scimitar bill and tree pipit (one individual each).

scholarly journals Detectability of Non-passerines Using "Pishing" in Eastern Ontario Woodlands

2005 ◽  
Vol 119 (3) ◽  
pp. 377 ◽  
Author(s):  
J. Ryan Zimmerling
Keyword(s):  
Species Richness ◽  
Continuous Series ◽  
Point Count ◽  
Point Counts ◽  
Passerine Species ◽  
Count Method ◽  
Eastern Ontario ◽  
Presence And Absence ◽  
Point Count Method

During spring and summer 1997, non-passerines were surveyed in three woodlots near Arnprior, Ontario, using standard point counts, and standard point counts combined with “pishing” (pishing involves the observer saying the words “pish pish pish pish” in a continuous series of short bursts). Of the 27 non-passerine species detected, 22 were recorded on more days using pishing as opposed to the standard point count method. However, only three of these species were recorded on significantly more days using pishing. Several woodpecker species approached more closely during point counts with pishing, which facilitated identification. In contrast, raptors and some other non-passerines that may have otherwise gone unnoticed were identified as they fled from the pishing sound. Hence, when the overall goal of research is to detect species richness or to gather presence and absence data in woodlands, point counts combined with pishing may increase detectability of some non-passerines.

scholarly journals On the use of 10-minute point counts and 10-species lists for surveying birds in lowland Atlantic Forests in southeastern Brazil

2012 ◽  
Vol 52 (28) ◽  
pp. 333-340 ◽  
Author(s):  
Vagner Cavarzere ◽  
Thiago Vernaschi Vieira da Costa ◽  
Luís Fábio Silveira
Keyword(s):  
Rapid Assessment ◽  
Southeastern Brazil ◽  
Point Counting ◽  
Point Count ◽  
Point Counts ◽  
Time Period ◽  
Minute Point ◽  
Species Lists ◽  
Point Count Method ◽  
Breeding Seasons

Due to rapid and continuous deforestation, recent bird surveys in the Atlantic Forest are following rapid assessment programs to accumulate significant amounts of data during short periods of time. During this study, two surveying methods were used to evaluate which technique rapidly accumulated most species (> 90% of the estimated empirical value) at lowland Atlantic Forests in the state of São Paulo, southeastern Brazil. Birds were counted during the 2008-2010 breeding seasons using 10-minute point counts and 10-species lists. Overall, point counting detected as many species as lists (79 vs. 83, respectively), and 88 points (14.7 h) detected 90% of the estimated species richness. Forty-one lists were insufficient to detect 90% of all species. However, lists accumulated species faster in a shorter time period, probably due to the nature of the point count method in which species detected while moving between points are not considered. Rapid assessment programs in these forests will rapidly detect more species using 10-species lists. Both methods shared 63% of all forest species, but this may be due to spatial and temporal mismatch between samplings of each method.

scholarly journals Singing in the suburbs: point count surveys efficiently reveal habitat associations for nocturnal Orthoptera across an urban-to-rural gradient

2020 ◽  
Vol 24 (6) ◽  
pp. 1031-1043
Author(s):  
Darin J. McNeil ◽  
Christina M. Grozinger
Keyword(s):  
Site Occupancy ◽  
Habitat Associations ◽  
Survey Method ◽  
Population Declines ◽  
Detection Rates ◽  
Point Count ◽  
Point Counts ◽  
Focal Species ◽  
Habitat Gradient ◽  
Count Surveys

Abstract As evidence for global insect population declines continues to amass, several studies have indicated that Orthoptera (grasshoppers, crickets, and katydids) are among the most threatened insect groups. Understanding Orthoptera populations across large spatial extents requires efficient survey protocols, however, many previously established methods are expensive and/or labor-intensive. One survey method widely employed in wildlife biology, the aural point count, may work well for crickets and katydids (suborder: Ensifera) because males produce conspicuous, species-specific mating calls. We conducted repeated point count surveys across an urban-to-rural gradient in central Pennsylvania. Occupancy analyses of ten focal species indicated that, although detection probability rates varied by species from 0.43 to 0.98, detection rates compounded over five visits such that all focal species achieved cumulative > 0.90. Factors associated with site occupancy varied among species with some positively associated with urbanization (e.g., Greater Anglewing, Microcentrum rhombifolium), some negatively associated with urbanization (e.g., Sword-bearing Conehead, Neoconocephalus ensiger), and others exhibiting constant occupancy across a habitat gradient (e.g., Common True Katydid, Pterophylla camellifolia). Our community-level analysis revealed that different species’ habitat associations interacted such that intermediate levels of urbanization (i.e., suburbs) hosted the highest number of species. Implications for insect conservation Ultimately, our analyses clearly support the concept that aural point counts paired with static occupancy modeling can serve as an important tool for monitoring night-singing Orthoptera populations. Applications of point count surveys by both researchers and citizen scientists may improve our understanding Ensifera populations and help in the global conservation of these threatened insects.

scholarly journals Estimating Detection Probability and Density from Point-Count Surveys: A Combination of Distance and Double-Observer Sampling

The Auk ◽  
2006 ◽  
Vol 123 (3) ◽  
pp. 735-752 ◽  
Author(s):  
Michelle L. Kissling ◽  
Edward O. Garton
Keyword(s):  
Detection Probability ◽  
Survey Methods ◽  
Effective Area ◽  
Survey Method ◽  
Density Estimates ◽  
Point Count ◽  
Detection Probabilities ◽  
Fixed Radius ◽  
Count Surveys ◽  
Double Observer

Abstract Point counts are the method most commonly used to estimate abundance of birds, but they often fail to account properly for incomplete and variable detection probabilities. We developed a technique that combines distance and double-observer sampling to estimate detection probabilities and effective area surveyed. We applied this paired-observer, variable circular-plot (POVCP) technique to point-count surveys (n = 753) conducted in closed-canopy forests of southeast Alaska. Distance data were analyzed for each species to model a detection probability for each observer and calculate an estimate of density. We then multiplied each observer's density estimates by a correction factor to adjust for detection probabilities <1 at plot center. We compared analytical results from four survey methods: single-observer fixed-radius (50-m) plot; single-observer, variable circular-plot (SOVCP); double-observer fixed-radius (50-m) plot; and POVCP. We examined differences in detection probabilities at plot center, effective area surveyed, and densities for five bird species: Pacific-slope Flycatcher (Empidonax difficilis), Winter Wren (Troglodytes troglodytes), Golden-crowned Kinglet (Regulus satrapa), Hermit Thrush (Catharus guttatus), and Townsend's Warbler (Dendroica townsendi). Average detection probabilities for paired observers increased ≈8% (SE = 2.9) for all species once estimates were corrected for birds missed at plot center. Density estimators of fixed-radius survey methods were likely negatively biased, because the key assumption of perfect detection was not met. Density estimates generated using SOVCP and POVCP were similar, but standard errors were much lower for the POVCP survey method. We recommend using POVCP when study objectives require precise estimates of density. Failure to account for differences in detection probabilities and effective area surveyed results in biased population estimators and, therefore, faulty inferences about the population in question. Estimaciones de la Densidad y de las Probabilidades de Detección a Partir de Muestreos Utilizando Conteos en Puntos: Una Combinación de Muestreos de Distancia y de Doble Observador

scholarly journals Factors influencing the appearance of spider (Araneae) and beetle (Coleoptera) assemblages in nests of great reed warbler Acrocephalus arundinaceus

Biologia ◽  
2014 ◽  
Vol 69 (7) ◽  
Author(s):  
Thomas Mérő ◽  
Maja Janjatović ◽  
Roland Horváth ◽  
Katarina Mrkobrad ◽  
Antun Žuljević
Keyword(s):  
Species Richness ◽  
Great Reed Warbler ◽  
Acrocephalus Arundinaceus ◽  
Reed Warbler ◽  
Factors Influencing ◽  
Significant Difference ◽  
Beetle Assemblages ◽  
Potential Factors ◽  
Spider Abundance ◽  
Species Richness And Abundance

AbstractThe appearance of spider (Araneae) and beetle (Coleoptera) assemblages found in nests of great reed warbler Acrocephalus arundinaceus was studied, firstly to investigate breeding success and the amount of precipitation as potential factors which might affect the abundance and species richness of both groups. In addition, we compared the diversity of spider and beetle assemblages between nests found in different reed habitats, and considered the position of nests (above water or dry ground). In this study we selected five different randomly chosen reed habitats: two mining ponds, two small canals and one large canal. Great Reed Warbler nests were collected either shortly after fledging, or after the clutch had failed. Altogether, 12 species of spider and 19 species of beetle were collected. In both groups there was no significant difference in abundance between successful, lost and cuckoo-parasitized nests; however, there was a significant difference in species richness between the three nest categories in spider assemblages, which was not the case in beetle assemblages. The amount of precipitation did not affect beetle or spider abundance; only the species richness of spiders showed significant growth. Furthermore, we found no significant relationship between vegetation cover and the species richness and abundance of spiders and beetles. The diversity of both groups differed significantly according to reed habitat: beetle assemblages were most diverse by the large canal and spiders at the mining ponds.

scholarly journals Population distribution and habitat analysis of Rufous treepie (Dendrocitta vagabunda) in Abbottabad, Pakistan

2023 ◽  
Vol 83 ◽  
Author(s):  
R. A. Khan ◽  
Z. Ullah ◽  
I. Uz Zaman ◽  
M. S. Khan ◽  
S. Mahmood ◽  
...  
Keyword(s):  
Population Distribution ◽  
Suitable Habitat ◽  
Importance Value Index ◽  
Importance Value ◽  
Monthly Basis ◽  
Point Count ◽  
Habitat Analysis ◽  
Significant Difference ◽  
Point Count Method ◽  
Order Passeriformes

Abstract The Rufous treepie (Dendrocitta vagabunda) belongs to family corvidae, order Passeriformes which includes about 100 species. The current study was conducted to gather information about the Population distribution and habitat analysis of D. vagabunda at District Abbottabad, Pakistan. The data were collected on monthly basis both morning and evening times (2018-2019). “The ‘’Point count Method” was used for population estimation and ‘’Quadrates Method” for habitat analysis of study area. The result shows an average month-wise population density of D. vagabunda was maximum at Jhangra 0.14±0.039/ha, whereas minimum at Havelian 0.11±0.022/ha. There was no significant difference (p>0.05) among monthly population densities of D. vagabunda, however, a significant difference (p<0.05) was found between morning and evening times population of the specie. The present study revealed that importance value index (IVI) of plants species at Sherwan, Bakot, Havelian, Langra and Jhangra were 59.6±12.6, 50.1±6.9, 53.4±6.3, 66.8±10 and 60.1±7.7. Likewise, the frequency of shrubs at Sherwan, Bakot, Havelian, Langra and Jhangra were 33.3±4.2, 45±9.4, 46.7±8.2, 55.6±22.2 and 37.5±8.5. Similarly, the frequency of herbs at Sherwan, Bakot, Havelian, Langra and Jhangra were 40.4±6.0, 37.5±5.6, 53.3±7.4, 48.5±5.2 and 46.9±7.4 respectively. Our results show the study area as suitable habitat for D. vagabunda.

scholarly journals Autonomous bird sound recording outperforms direct human observation: Synthesis and new evidence

2017 ◽  
Author(s):  
Kevin Darras ◽  
Péter Batáry ◽  
Brett Furnas ◽  
Irfan Fitriawan ◽  
Yeni Mulyani ◽  
...  
Keyword(s):  
Species Richness ◽  
Signal To Noise Ratio ◽  
Survey Methods ◽  
Meta Analysis ◽  
High Signal ◽  
List Type ◽  
Sound Recording ◽  
Data Types ◽  
Point Counts ◽  
Recording Techniques

Abstract1)Autonomous sound recording techniques have gained considerable traction in the last decade, but the question still remains whether they can replace human observation surveys to sample some animal taxa. Especially bird survey methods have been tested using classical point counts and autonomous sound recording techniques.2)We review the latest information by comparing both survey methods' standardization, verifiability, sampling completeness, data types, compatibility, and practicality by means of a systematic review and a meta-analysis of alpha and gamma species richness levels sampled by both methods across 20 separate studies.3)Although sound recording surveys have hitherto not enjoyed the most effective setups, they yield very similar results in terms of alpha and gamma species richness. We also reveal the crucial importance of the microphone (high signal-to-noise ratio) as the sensor that replaces human senses.4)We discuss key differences between both methods, while richness estimates are closely related and 81% of all species were detected by both methods. Sound recording techniques provide a more powerful and promising tool to monitor birds in a standardized, verifiable, and exhaustive way against the golden standard of point counts. Advantages include the capability of sampling continuously through day or season and of difficult-to-reach regions in an autonomous way, avoidance of observer bias and human disturbance effects and higher detection probability of rare species due to extensive recordings.

scholarly journals Raptor assemblages in grasslands of Southern Brazil: species richness and abundance and the influence of the survey method

2013 ◽  
Vol 52 (1) ◽  
Author(s):  
Felipe Zilio ◽  
Alan Bolzan ◽  
André de Mendonça-Lima ◽  
Cristiane Oliveira da Silva ◽  
Laura Verrastro ◽  
...  
Keyword(s):  
Species Richness ◽  
Survey Method ◽  
Southern Brazil ◽  
Species Richness And Abundance

scholarly journals Species richness and abundance of forest birds in relation to radiation at Chernobyl

2007 ◽  
Vol 3 (5) ◽  
pp. 483-486 ◽  
Author(s):  
A.P Møller ◽  
T.A Mousseau
Keyword(s):  
Species Richness ◽  
Background Radiation ◽  
Soil Layer ◽  
Breeding Birds ◽  
Ecological Effects ◽  
Exclusion Zone ◽  
Point Counts ◽  
Forest Sites ◽  
Species Richness And Abundance ◽  
Effects Of Radiation

The effects of low-level radiation on the abundance of animals are poorly known, as are the effects on ecosystems and their functioning. Recent conclusions from the UN Chernobyl forum and reports in the popular media concerning the effects of radiation from Chernobyl on animals have left the impression that the Chernobyl exclusion zone is a thriving ecosystem, filled with an increasing number of rare species. Surprisingly, there are no standardized censuses of common animals in relation to radiation, leaving the question about the ecological effects of radiation unresolved. We conducted standardized point counts of breeding birds at forest sites around Chernobyl differing in level of background radiation by over three orders of magnitude. Species richness, abundance and population density of breeding birds decreased with increasing level of radiation, even after controlling statistically for the effects of potentially confounding factors such as soil type, habitat and height of the vegetation. This effect was differential for birds eating soil invertebrates living in the most contaminated top soil layer. These results imply that the ecological effects of Chernobyl on animals are considerably greater than previously assumed.

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