scholarly journals Habitat and Landscape Suitability as Indicators of Bird Abundance in Created and Restored Wetlands

ISRN Ecology ◽  
2011 ◽  
Vol 2011 ◽  
pp. 1-10 ◽  
Author(s):  
Jordan W. Mora ◽  
John N. Mager III ◽  
Douglas J. Spieles
Keyword(s):  
Bird Species ◽  
Land Development ◽  
Logistic Models ◽  
Field Measurements ◽  
Road Density ◽  
Bird Abundance ◽  
Aerial Photos ◽  
Landscape Variables ◽  
Buffer Width ◽  
Landscape Scales

We used aerial photography, field measurements, and bird surveys to evaluate 7 Ohio mitigation wetlands for their capacity to support avian guilds at both local and landscape scales. At the local scale, we assessed each wetland with habitat suitability indices (HSI) for eight wetland-dependent bird species as indicators for four guilds: wading, diving, dabbling, and emergent dependent. We characterized landscapes within 2.5 km of each wetland by measuring the buffer width, road density, connectedness, and anthropogenic land development. The changes in landscape variables over time were determined by comparison of aerial photos taken near the time of wetland construction and near the time of this study. Bird abundance data were poorly correlated with HSI scores but were well described with logistic models of buffer width, wetland area, and road density. Our results suggest that landscape variables are better predictors of bird abundance than HSI scores for these guilds in these wetlands.

scholarly journals Riparian Bird Community Structure in Portland, Oregon: Habitat, Urbanization, and Spatial Scale Patterns

The Condor ◽  
2003 ◽  
Vol 105 (2) ◽  
pp. 288-302 ◽  
Author(s):  
Lori A. Hennings ◽  
W. Daniel Edge
Keyword(s):  
Native Species ◽  
Forest Canopy ◽  
Urban Canopy ◽  
Canopy Cover ◽  
Bird Community ◽  
Metropolitan Region ◽  
Road Density ◽  
Breeding Bird ◽  
Bird Abundance ◽  
Neotropical Migrant

Abstract In 1999, we surveyed breeding bird and plant communities along 54 streams in the Portland, Oregon, metropolitan region to link bird community metrics with structural and spatial characteristics of urban riparian areas. Canonical correspondence analysis produced two explanatory axes relating to vegetation and road density. Total and non-native bird abundance was higher in narrow forests. Native bird abundance was greater in narrow forests surrounded by undeveloped lands; native species richness and diversity were greater in less-developed areas. Native resident and short-distance-migrant abundance was higher in narrow forests, and diversity was positively associated with developed lands. Neotropical migrant abundance, richness, and diversity were greater in open-canopied areas with fewer roads. We examined spatial relationships by regressing bird variables on satellite-derived forest canopy cover, area of undeveloped lands, and street density in a series of 50-m buffers within a 500-m radius around study sites. Non-native bird abundance decreased with increasing canopy cover within 450 m, but most other relationships were strongest at smaller scales (50–100 m). Our results suggest that increasing urban canopy cover is the most valuable land management action for conserving native breeding birds. A hierarchical scheme for Neotropical migrant conservation might include increasing forest canopy within 450 m of streams to control non-native species and cowbirds; reducing street density within a 100-m radius of streams; and conserving or planting onsite native trees and shrubs. Estructura de Comunidades Riparias de Aves en Portland, Oregon: Hábitat, Urbanización y Patrones de Escala Espacial Resumen. Censamos las comunidades de aves reproductivas y plantas a lo largo de 54 arroyos en el área metropolitana de Portland, Oregon en 1999 para conectar medidas de comunidades de aves con características estructurales y espaciales de zonas riparias urbanas. Análisis de correspondencia canónica produjeron dos ejes explicativos relacionados con la vegetación y la densidad de carreteras. La abundancia total de aves y la de aves no nativas fueron mayores en bosques estrechos. La abundancia de aves nativas fue mayor en bosques estrechos rodeados por terrenos rurales y la riqueza y diversidad de especies fueron mayores en áreas menos desarrolladas. La abundancia de residentes nativas y migratorias de corta distancia fue mayor en bosques estrechos y su diversidad estuvo asociada positivamente con terrenos desarrollados. La abundancia, riqueza y diversidad de las migratorias neotropicales fueron mayores en áreas de dosel abierto y con pocas carreteras. Examinamos las relaciones espaciales mediante regresiones entre variables de aves y la cobertura del dosel derivada de imágenes satelitales, el área de terrenos sin desarrollar y la densidad de calles en una serie de áreas de 50 m de ancho en un radio de 500 m alrededor de los sitios de estudio. La abundancia de aves no nativas disminuyó con aumentos en la cobertura del dosel hasta 450 m, pero la mayoría de las demás relaciones fueron más fuertes a escalas menores (50–100 m). Nuestros resultados sugieren que el incremento de la cobertura del dosel en áreas urbanas es la estrategia de manejo más valiosa para conservar las aves nativas que se reproducen en el área. Un esquema jerárquico para la conservación de las migratorias neotropicales podría incluir aumentar la cobertura de bosque a menos de 450 m de los arroyos para controlar a las especies no nativas y a los Molothrus, reducir la densidad de calles dentro de un radio de 100 m alrededor de los arroyos y conservar o plantar árboles y arbustos nativos.

scholarly journals A Fixed-radius Point Count Method for Nonbreeding and Breeding Season Use

The Auk ◽  
1986 ◽  
Vol 103 (3) ◽  
pp. 593-602 ◽  
Author(s):  
Richard L. Hutto ◽  
Sandra M. Pletschet ◽  
Paul Hendricks
Keyword(s):  
Bird Species ◽  
Common Species ◽  
Bird Abundance ◽  
Point Count ◽  
Bird Density ◽  
Count Method ◽  
Species Abundances ◽  
Fixed Radius ◽  
Point Count Method ◽  
A Site

Abstract We provide a detailed description of a fixed-radius point count method that carries fewer assumptions than most of the currently popular methods of estimating bird density and that can be used during both the nonbreeding and breeding seasons. The method results in three indices of bird abundance, any of which can be used to test for differences in community composition among sites, or for differences in the abundance of a given bird species among sites. These indices are (1) the mean number of detections within 25 m of the observer, (2) the frequency of detections within 25 m of the observer, and (3) the frequency of detections regardless of distance from the observer. The overall ranking of species abundances from a site is similar among the three indices, but discrepancies occur with either rare species that are highly detectable at great distances or common species that are repulsed by, or inconspicuous when near, the observer. We argue that differences in the behavior among species will preclude an accurate ranking of species by abundance through use of this or any other counting method in current use.

scholarly journals Fire effects on the composition of a bird community in an amazonian Savanna (Brazil)

2005 ◽  
Vol 65 (4) ◽  
pp. 683-695 ◽  
Author(s):  
R. Cintra ◽  
T. M. Sanaiotti
Keyword(s):  
Species Richness ◽  
Community Composition ◽  
Spatial Scales ◽  
Bird Species ◽  
Bird Community ◽  
Fire Effects ◽  
Bird Abundance ◽  
Bird Species Richness ◽  
Byrsonima Crassifolia ◽  
Mist Net

The effects of fire on the composition of a bird community were investigated in an Amazonian savanna near Alter-do-Chão, Pará (Brazil). Mist-net captures and visual counts were used to assess species richness and bird abundance pre- and post-fire in an approximately 20 ha area. Visual counts along transects were used to survey birds in an approximately 2000 ha area in a nearby area. Results using the same method of ordination analysis (multidimensional scaling) showed significant effects of fire in the 20 ha and 2000 ha areas and strongly suggest direct effects on bird community composition. However, the effects were different at different spatial scales and/or in different years, indicating that the effects of fire vary spatially and/or temporally. Bird community composition pre-fire was significantly different from that found post-fire. Using multiple regression analysis it was found that the numbers of burned and unburned trees were not significantly related to either bird species richness or bird abundance. Two months after the fire, neither bird species richness nor bird abundance was significantly related to the number of flowering trees (Lafoensia pacari) or fruiting trees (Byrsonima crassifolia). Since fire is an annual event in Alter-do-Chão and is becoming frequent in the entire Amazon, bird community composition in affected areas could be constantly changing in time and space.

scholarly journals Power to Detect Trend in Short-Term Time Series of Bird Abundance

The Condor ◽  
2007 ◽  
Vol 109 (4) ◽  
pp. 943-948
Author(s):  
Wayne E. Thogmartin ◽  
Brian R. Gray ◽  
Maureen Gallagher ◽  
Neal Young ◽  
Jason J. Rohweder ◽  
...  
Keyword(s):  
Sample Size ◽  
Short Duration ◽  
Bird Species ◽  
Population Monitoring ◽  
Short Term ◽  
Wet Prairie ◽  
Bird Abundance ◽  
Point Counts ◽  
Study Sites ◽  
Species Specific

Abstract Avian point counts for population monitoring are often collected over a short timespan (e.g., 3–5 years). We examined whether power was adequate (power ≥0.80) in short-duration studies to warrant the calculation of trend estimates. We modeled power to detect trends in abundance indices of eight bird species occurring across three floodplain habitats (wet prairie, early successional forest, and mature forest) as a function of trend magnitude, sample size, and species-specific sampling and among-year variance components. Point counts (5 min) were collected from 365 locations distributed among 10 study sites along the lower Missouri River; counts were collected over the period 2002 to 2004. For all study species, power appeared adequate to detect trends in studies of short duration (three years) at a single site when exponential declines were relatively large in magnitude (more than −5% year−1) and the sample of point counts per year was ≥30. Efforts to monitor avian trends with point counts in small managed lands (i.e., refuges and parks) should recognize this sample size restriction by including point counts from offsite locations as a means of obtaining sufficient numbers of samples per strata. Trends of less than −5% year−1 are not likely to be consistently detected for most species over the short term, but short-term monitoring may still be useful as the basis for comparisons with future surveys.

scholarly journals Winter bird abundance, species richness and functional guild composition at Delhi’s ponds: does time of day and wetland extent matter?

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Prakhar Rawal ◽  
Swati Kittur ◽  
Murali Krishna Chatakonda ◽  
K S Gopi Sundar
Keyword(s):  
Species Richness ◽  
Species Abundance ◽  
Bird Species ◽  
Time Of Day ◽  
Conservation Priorities ◽  
Bird Abundance ◽  
Functional Guilds ◽  
Β Diversity ◽  
Functional Guild ◽  
Guild Composition

Abstract Urbanisation can limit species persistence and bias composition of functional guilds with serious consequences for ecosystem functioning and conservation planning. Standardised biodiversity surveys are missing at most tropical urban cities where biodiversity levels are high alongside rapidly increasing rates of urbanisation. We explored the utility of time-bound surveys to document winter birds at ponds (wetlands ≤ 5 ha) in Delhi, India at two different times of the day (morning and evening) and in areas with varying extents of wetlands. Systematic surveys at 39 ponds during January–March 2020 yielded an estimated 173 ± 22 bird species (∼37% of Delhi’s birds). The total bird species assemblage at ponds did not vary significantly with time of day, but β-diversity increased marginally with increasing extent of wetlands. Total bird abundance and species richness varied substantially with time of day, with differences apparent across several species rich functional feeding and habitat guilds. Abundance and species richness of some guilds, including species-poor guilds, varied in ponds located in areas with differing extent of wetlands. Reliable and comparable measures of species abundance and species richness (both total and across functional guilds)— metrics commonly used to set research and conservation priorities—in urban habitats can be obtained after appropriately standardising field effort. Such standardised efforts can help underscore the importance of maintaining and improving erstwhile-ignored habitats such as unprotected ponds that are providing refugia to hundreds of bird species in mega-cities like Delhi.

Predicting deposition of debris flows in mountain channels

1990 ◽  
Vol 27 (4) ◽  
pp. 409-417 ◽  
Author(s):  
Lee E. Benda ◽  
Terrance W. Cundy
Keyword(s):  
Pacific Northwest ◽  
Debris Flows ◽  
Field Measurements ◽  
Coast Range ◽  
Oregon Coast Range ◽  
Oregon Coast ◽  
Aerial Photos ◽  
The Pacific ◽  
Channel Slope ◽  
Junction Angle

An empirical model for predicting deposition of coarse-textured debris flows in confined mountain channels is developed based on field measurements of 14 debris flows in the Pacific Northwest, U.S.A. The model uses two criteria for deposition: channel slope (less than 3.5°) and tributary junction angle (greater than 70°). The model is tested by predicting travel distances of 15 debris flows in the Oregon Coast Range and six debris flows in the Washington Cascades, U.S.A. The model is further tested on 44 debris flows in two lithological types in the Oregon Coast Range using aerial photos and topographic maps; on these flows only the approximate travel distance is known. The model can be used by resource professionals to identify the potential for impacts from debris flows. Key words: debris flow, deposition, travel, erosion.

Increased grazing and dominance of an exotic pasture (Bothriochloa pertusa) affects vertebrate fauna species composition, abundance and habitat in savanna woodland

2011 ◽  
Vol 33 (1) ◽  
pp. 49 ◽  
Author(s):  
Alex S. Kutt ◽  
Alaric Fisher
Keyword(s):  
Species Composition ◽  
Bird Species ◽  
Information Criteria ◽  
Tree Cover ◽  
Theoretic Approach ◽  
Pasture Grass ◽  
Bird Abundance ◽  
Vertebrate Fauna ◽  
Species Response ◽  
Information Theoretic Approach

The invasion of exotic pasture species into intact woodlands has the potential to affect native fauna by altering habitat structure and ecosystem function. The spread of these weeds is generally in concert with cattle grazing, so that fauna or habitat change is due to multiple interrelated causes. In this study we investigated whether the spread of the introduced pasture grass Bothriochloa pertusa and replacement of the native bluegrass B. ewartiana in eucalypt woodlands of northern Queensland has had an effect on terrestrial vertebrate fauna. We located 40 sites that sampled a range of native and introduced pastures cover, and investigated the spatial pattern of abundance with canonical analysis of principle coordinates, and correlation of the habitat attributes on the ordination space. We then selected a subset of four habitat attributes (eliminating highly colinear variables) and modelled species response to each using an information-theoretic approach. Thirty-one species (26 birds, one mammal and four reptiles) and two summary variables (bird abundance and richness) had best subset Akaike Information Criteria models with reliable parameters estimates. Seventeen models contained the B. pertusa frequency term and a further 16 had a term relating to upper storey cover (tree cover >10, 5–10 or 3–5 m). Though pasture grass cover, grazing and habitat features were correlated and thus we cannot ascribe B. pertusa as the sole determinant of fauna species change, this study has demonstrated that tropical savanna woodlands with changing Bothriochloa dominance from native to introduced species have different fauna species composition. In particular bird species richness, ground nesting species (e.g. rufous songlark Cincloramphus mathewsi, golden-headed cisticola Cisticola exilis) and terrestrial reptiles (e.g. Carlia munda and Ctenotus taeniolatus) declined. Disturbance-tolerant species such as Australian magpie Cracticus tibicen and yellow-throated miners Manorina flavigula increased in abundance in exotic pasture-dominated sites. As pastoral intensification continues in northern Australian rangelands there is a potential for significant change in the relative abundance and composition of vertebrate fauna and the reduction or loss of some species in the landscape.

Bird communities and vegetation associations across a treeline ecotone in the Mealy Mountains, Labrador, which is an understudied part of the boreal forest

2015 ◽  
Vol 93 (6) ◽  
pp. 477-486 ◽  
Author(s):  
Keith P. Lewis ◽  
Brian M. Starzomski
Keyword(s):  
Species Composition ◽  
Bird Species ◽  
Bird Communities ◽  
Tree Cover ◽  
Strong Impact ◽  
Avian Diversity ◽  
Bird Abundance ◽  
Treeline Ecotone ◽  
Point Counts ◽  
Deciduous Shrub

We examined the factors structuring bird communities across a complex subarctic treeline in the Mealy Mountains, Labrador, Canada. Using point counts of bird abundance in 2007 and 2008, we show that changes in vegetation driven by elevation are strongly correlated with avian community structure in this treeline ecotone system. Overall, avian diversity was higher in the forest compared with other habitat classes (krummholz, deciduous shrub, and alpine). There were strong correlations between avian diversity and vegetation richness, as well as structure, among and within habitat class in 2008. Numerous habitat types (subset of habitat class) were correlated with avian composition, although some species were clearly habitat generalists. Contrary to expectation, avian species composition was associated with physiognomy (vegetation structure) in alpine and deciduous shrub, and with either physiognomy or floristics (vegetation species composition) in krummholz and forest. Given the strong impact of elevation on vegetation and the demonstrated influence on bird communities, we note that for bird species whose near-southernmost populations are found in the Mealy Mountains, climate change is likely to have a strong negative effect if alpine tundra habitat is lost. Furthermore, forest bird species are likely to benefit from the increased tree cover as treeline moves poleward and upward.

scholarly journals Efecto de la estacionalidad y lluvias en la avifauna del Chaco Serrano Austral, Argentina

2017 ◽  
Vol 65 (3) ◽  
pp. 953
Author(s):  
Gustavo Alfredo Fava ◽  
Juan Carlos Acosta ◽  
Graciela Mirta Blanco
Keyword(s):  
Bird Species ◽  
Reproductive Activity ◽  
Breeding Habitat ◽  
Bird Abundance ◽  
Group Management ◽  
Natural Park ◽  
Chaco Serrano ◽  
Site Survey ◽  
Migrant Bird ◽  
Resident Bird

In subtropical regions like the Chaco Serrano (33° S), rainfall has a marked seasonality, and water flood, caused by heavy rains, may have important consequences for dependent ecosystems. Conversely, the high pressure on available resources during dry periods can also affect the fauna diversity and distribution. Even though birds have shown to be excellent ecological indicators of these shifts in the environment, currently little is known about the avifauna of the Argentine Chaco Serrano phytogeographic district. Our aim was to study the resident bird population status in the Southern Chaco Serrano, its fluctuations in richness and abundance, and its relationship to seasonal variations, in monthly and annual hydroperiods. In order to assess the resident bird status over a two year period (2011 Mar.-2013 Feb.) we carried out 18 sampling surveys during pre-breeding (spring), breeding (summer) and non breeding periods (autumn-winter), in the Northeastern part of the Valle Fértil Natural Park, San Juan province, Argentina. During each site survey, we recorded bird assemblages found in six transects, and obtained bird abundance and species diversity. A mixed general linear model was employed to evaluate relationships between the studied variables. We found a total of 98 species of birds belonging to 33 families (44 resident species, 23 spring visitors, six summer visitors, two winter visitors and 23 with scarce registers). We also registered 68 of these species in both hydroperiods, 28 only during rainy periods and only two during the dry period. Both richness and abundance showed the highest values during the pre-breeding and rainy seasons, while different tendencies were detected during the isolated monthly rainfalls. These changes in bird densities were associated with the arrival of migratory species, mainly spring visitors, and probably in relationship with their reproductive activity, and to seasonal fluctuations in food resources. The Southern Chaco Serrano is a subtropical semiarid place that seems to be an important breeding habitat for many migrant bird species, which in turn promoted seasonal changes in species density and diversity, mainly during rainy years. This work contributed to our understanding on the causes of richness and abundance variations on birds, and will contribute to this important group management and conservation in this area.

scholarly journals Why a landscape view is important: nearby urban and agricultural land affects bird abundances in protected areas

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e10719
Author(s):  
Gregory Duncan Duckworth ◽  
Res Altwegg
Keyword(s):  
Land Use ◽  
Protected Areas ◽  
Urban Area ◽  
Protected Area ◽  
Agricultural Land ◽  
Bird Species ◽  
Grid Cell ◽  
Land Use Type ◽  
Bird Abundance ◽  
Land Use Types

Protected areas are one of the primary conservation tools used worldwide. However, they are often embedded in a landscape that is intensely used by people, such as for agriculture or urban development. The proximity of these land-use types to protected areas can potentially affect the ecological effectiveness (or conservation effectiveness) of protected areas. In this article, we examine to what degree adjacent agricultural and urban land uses affect the ecological effectiveness of protected areas over the greater Gauteng region of South Africa. We selected 198 common, resident bird species, and analysed detection/non-detection data for these species collected over regular grid cells (approximately 61 km2 in area). For each species, we estimated abundance per grid cell with the Royle-Nichols model in relation to the proportion of protected area as a covariate. Our study focused on how this relationship between proportion of protected area and abundance (which we term the ‘protection–abundance relationship’) changed as a function of other land-use types in the grid cell. Specifically, we examined the interaction effects between protected area and both urban and agricultural land-use type per grid cell on bird abundance. We assigned each species to one of seven guilds, namely: frugivores, gleaners, granivores, ground-feeders, hawkers, predators and vegivores, and examined how the protection–abundance relationship varied across guilds in relation to agriculture and urban area. As urban area within a grid cell increased, the protection–abundance relationship became more positive for 58% of all species. At the level of guilds, the protection–abundance relationship became more positive for two guilds (granivores and ground-feeders), more negative for frugivores, and remained unchanged for the other four guilds (gleaners, hawkers, predators and vegivores). As agricultural area within a grid cell increased, the protection–abundance relationship became more positive for 49% of all species. At the guild level, the protection–abundance relationship became more positive for six guilds (frugivores, gleaners, ground-feeders, hawkers, predators and vegivores) and remained unchanged for the granivores. Our results show land-use type near protected areas modified the effect protected areas had on bird abundances, and hence the ecological effectiveness of protected areas. Our results suggest that protected areas should be viewed as constituents within the landscape, rather than islands of protection.

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