Assessment of Counting Techniques

Verner, Jared

doi:10.1007/978-1-4613-2385-3_8

Cited by 367 publications

(295 citation statements)

References 43 publications

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“…We used a 'standardized search' method covering all the microhabitats we could locate in each subregion (Fjeldsa, 1999;Herzog et al, 2002;Watson, 2003). During standardized searches, an experienced observer walked throughout each site so that secretive species, that might go unnoticed on point counts, could be detected (Verner, 1985;Terborgh et al, 1990;Fjeldsa, 1999;Robinson, 1999;Robinson et al, 2000;Herzog et al, 2002;Watson, 2003). This method has been used successfully for rapid assessment of species richness in Neotropical bird communities.…”

Section: Methods Of Surveyingmentioning

confidence: 99%

Environmental correlates of avian diversity in lowland Panama rain forests

Rompré

Robinson

Desrochers

et al. 2007

Journal of Biogeography

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Aim The composition of communities is known to be influenced by biogeographical history, but also by local environmental conditions. Yet few studies have evaluated the relative importance of the direct and indirect effects of multiple factors on species diversity in rich Neotropical forests. Our study aims to assess drivers of change in local bird species richness in lowland tropical rain forests.Location Thirty-two physiographic subregions along the corridor of the Panama Canal, Panama.Methods We mapped the distributions of all forest-dwelling bird species and quantified the environmental characteristics of all subregions, including mean annual rainfall, topographic complexity, elevational variability, forest age and forest area. Plant species richness, believed to be correlated with structural complexity, was estimated by interpolation through kriging for subregions where data were unavailable.Results The study region has a strong rainfall gradient across a short distance (65 km), which is also accompanied by steep gradients in plant and bird species diversity. Path analysis showed that precipitation strongly affected plant species diversity, which in turn affected avian diversity. Forest age and topography affected bird diversity independently of plant diversity. Forest area and its proportion occurring in the largest two fragments of each subregion (habitat configuration) were also positive correlates of bird species richness.Main conclusions Our results suggest that plant species richness, known to be influenced in part by biogeographical history and geology, also affects bird species assemblages locally. We provide support for the hypothesis that bird species richness increases with structural complexity of the habitat. Our analysis of the distributions of the region's most disturbance-sensitive bird species showed that subregions with more rainfall, more complex topography and older forests harboured not only richer communities but also more sensitive species; while subregions with the opposite characteristics usually lacked large fractions of the regional forest bird community and hosted only common, widely distributed species. Results also emphasize the importance of preserving forest diversity from habitat loss and fragmentation, and confirm that larger, continuous forest tracts are necessary to maintain the rich avian diversity in the region.

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Section: Methods Of Surveyingmentioning

confidence: 99%

Environmental correlates of avian diversity in lowland Panama rain forests

Rompré

Robinson

Desrochers

et al. 2007

Journal of Biogeography

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“…Field studies were carried out for three years during Jan. 2005 to Dec. 2007 using line transect method (Verner 1985). Depending upon the accessibility, four transects were laid in each habitat types at each altitudinal zone and each transect was visited once a month.…”

Section: Field Proceduresmentioning

confidence: 99%

Bird community structure in natural and urbanized habitats along an altitudinal gradient in Pauri district (Garhwal Himalaya) of Uttarakhand state, India

Naithani

Bhatt

2012

Biologia

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In the Indian subcontinent there is hardly any study that compares the bird community structure of urban/suburban areas with those of forest habitat. The present survey identified diverse assemblages of birds in the Pauri district at different elevations. A total of 125 bird species belonging to 40 families including two least count species (Lophura leucomelanos and Pucrasia marcolopha) were recorded during this survey in the forest and urbanized habitats of Pauri District (Garhwal Hiamalaya) of Uttarakhand state, India. The high elevation (Pauri 1600-2100 m a.s.l.), mid elevation (Srikot-Khanda 900-1300 m a.s.l.) and low elevation (Srinagar 500-900 m a.s.l.) contributed 88.8%, 63.2% and 58.4% of the total species respectively. Rarefaction analysis and Shannon diversity index showed that the high elevation forest habitat had highest bird species richness (BSR) and bird species diversity (BSD) followed by the mid and then the low elevation forests. BSR and BSD fluctuated across seasons at all elevations but not across habitat types. Present study provides a base line data about avian community composition in urbanized and natural habitats along altitudinal gradient in the study area. This information may be useful to the conservation biologists for the better management and conservation of the avifauna in the Western Himalaya, a part of one of the hot biodiversity spots of the world.

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“…The accuracy of each census is influenced by the bias and precision of the counting technique (Verner 1985;Bibby et al 2000). Especially in historical long-term datasets, biases may occur due to differences in study designs, aims, or techniques.…”

Section: Introductionmentioning

confidence: 99%

Monitoring of a Southern Giant Petrel Macronectes giganteus population on the Frazier Islands, Wilkes Land, Antarctica

et al. 2004

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Since 1956, Southern Giant Petrels on the Frazier Islands, East Antarctica, have been counted with different census techniques, sometimes varying within seasons and among islands, which hindered analysis of the data. Protective measures for the islands from 1986 onwards have increased the need for reliable long-term census data, but reduced the ways to collect these data. Published and unpublished data were re-examined, and population trends were reconstructed based on two relatively standardised techniques: the number of active chicks (AC) and the number of apparently occupied nests (AON) around hatching. AC-values from Nelly Island from 1959 to 1998 indicate substantial periodic fluctuations, but no consistent long-term change. Since the late 1970s, AC-values on the other two islands and AON-values suggest that the breeding population may have grown by 35%. This recent growth, however, is within the extent of periodic fluctuations observed in Southern Giant Petrel population that is stable over the long term.

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Assessment of Counting Techniques

Cited by 367 publications

References 43 publications

Environmental correlates of avian diversity in lowland Panama rain forests

Environmental correlates of avian diversity in lowland Panama rain forests

Bird community structure in natural and urbanized habitats along an altitudinal gradient in Pauri district (Garhwal Himalaya) of Uttarakhand state, India

Monitoring of a Southern Giant Petrel Macronectes giganteus population on the Frazier Islands, Wilkes Land, Antarctica

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