Powerline easements through forests: a case study of impacts on avifauna

1998 ◽  
Vol 4 (1) ◽  
pp. 79 ◽  
Author(s):  
Jack Baker ◽  
Ross L. Goldingay ◽  
Robert J. Whelan
Keyword(s):  
Species Richness ◽  
Bird Community ◽  
Forest Habitat ◽  
Bird Abundance ◽  
Point Counts ◽  
Southeastern Australia ◽  
Total Species Richness ◽  
New Type ◽  
Forest Values

Powerline easements are typically a strip cleared of trees and tall vegetation to a width of approximately 50 m. They may affect avifauna by modification and fragmentation of forest habitat. We investigated the responses of the bird community to easements at three sites in southeastern Australia using 25 m radius point-counts spaced at 50 m intervals from the easement to 300 m inside the forest. The easements caused an absolute loss of habitat for forest avifauna, with abundance and species richness at the easement less than 20% of the forest values. Four species of easement opportunist and one easement specialist provided evidence that the easement represented a new type of habitat for avifauna. A barrier effect of fragmentation may occur for four species of easement avoiders. These were small to medium-sized terrestrial birds associated with dense ground and/or understorey cover. The edge effect of fragmentation was an adverse impact on forest avifauna. At the margin (25?125 m from the easement) of the forest, bird abundance, mean species richness and total species richness were significantly less than the corresponding values for the interior (225?325 m) of the forest. The mean abundance at the sites varied from 13.0?17.7 birds/ha and the species richness varied significantly among sites. The adverse impacts of powerline easements on native avifauna could be minimized by site-specific management which includes strategies to minimize the loss of forest habitat and to ameliorate the effects of fragmentation.

scholarly journals Influence of Land-Use Type on Forest Bird Community Composition in Mount Kenya Forest

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Samuel N. Mahiga ◽  
Paul Webala ◽  
Mugo J. Mware ◽  
Paul K. Ndang’ang’a
Keyword(s):  
Land Use ◽  
Species Richness ◽  
Bird Community ◽  
Natural Forest ◽  
Forest Biodiversity ◽  
Natural Forests ◽  
Plantation Forest ◽  
Point Counts ◽  
Plantation Forests ◽  
Relative Species Richness

Few studies have explored how human land uses influence and support persistence of forest biodiversity in central Kenya. In the case of the Mount Kenya ecosystem, farmlands and plantation forests are significant land-use types. Using point counts, we assessed bird communities in natural forests, plantation forests, and farmlands in the Nanyuki Forest Block, Western Mount Kenya. Bird point counts were undertaken during two sampling periods (wet and dry season). Compared to farmlands and plantation forest, natural forest had the highest overall avian species richness and relative species richness of all except one forest-dependent foraging guild (granivores) and nonforest species, which occurred frequently only on farmlands. Plantation forest had the lowest relative richness of all avian habitat and foraging guilds. Conversely, specialist forest-dependent species mainly occurred in the structurally complex remnant natural forest. Our study underscores the importance of remnant natural forests for the persistence and conservation of forest biodiversity and risks posed by replacing them with plantation forests and farmlands.

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 Complex Small-Holder Agriculture in Rainforest Buffer Zone, Sri Lanka, Supports Endemic Birds

2021 ◽  
Vol 9 ◽  
Author(s):  
Juliana Hanle ◽  
Balangoda M. P. Singhakumara ◽  
Mark S. Ashton
Keyword(s):  
Land Use ◽  
Species Richness ◽  
Sri Lanka ◽  
Buffer Zone ◽  
Small Scale ◽  
Forest Fragments ◽  
Buffer Zones ◽  
Bird Abundance ◽  
Point Counts ◽  
Zone Management

The Sinharaja rainforest in southwestern Sri Lanka is a protected forest in a largely agriculture-dominated landscape. In keeping with global UNESCO global biosphere reserves planning, the Sinharaja is surrounded by a buffer zone of regenerating forest and villages with small tea plots and multi-strata tree gardens (homegardens). Globally, however, conservation planning lacks standards on buffer zone management. We ask what relationships exist between village land use and bird assemblages, which are effective ecosystem indicators. Birds have been little studied across land use and vegetation structure in actively managed, large, protected forest buffer zones. To that end, we ran spatially- and temporally-replicated bird point counts across tree gardens, forest fragments, and tea plots within a Sinharaja village. Tree gardens held a greater abundance of birds across habitat association, conservation concern, diet, and endemic species than forest fragments or tea plots. Forest fragments and tree gardens hosted statistically similar numbers of birds in some subsets, but their species assemblages differed. In tea plots, greater shade tree species richness correlated with greater bird abundance and species richness. Our results support the argument for programs to support complex small-scale tree-based agroforestry embedded in buffer zone regenerating forest.

scholarly journals Variations in Total Species Richness and the Unevenness of Species Abundance Distribution between Two Distant Conus Communities (Neogastropoda): A Case Study in Mannar Gulf (India)

2019 ◽  
pp. 1-18
Author(s):  
Jean Béguinot
Keyword(s):  
Species Richness ◽  
Species Composition ◽  
Species Abundance ◽  
Species Abundance Distribution ◽  
Abundance Distribution ◽  
Marine Gastropods ◽  
Total Species Richness ◽  
Species Recruitment ◽  
Total Species

The genus Conus forms a conspicuous and rather homogeneous group within marine Gastropods. This makes it all the more interesting to focus on the sub-communities formed by Conus species and to analyze the potential specificities in the internal organization of species in these communities, in particular species richness, species abundance distribution and the effect of geographical distance between communities on differences in their respective species composition. Accordingly, two Conus communities along the coast in Mannar Gulf (India), separated by 80 km, are considered. Reliable analysis requires, first, to treat exhaustive data from complete samplings or, else – as here – to implement an appropriate extrapolation procedure to complete numerically the partial samplings. After numerical completion, substantial differences were highlighted between the two communities, not only in terms of true (total) species richness but, even more, as regards the profile and the average unevenness of the distributions of species abundance. Also, significant dissimilarity in species composition was found between the two communities, that may be tentatively attributed to either deterministic distance decay in similarity of species composition or, alternatively, to the persistence in the stochastic process of species recruitment from the regional stock of Conus planktonic larvae. This preliminary study yet requests to be complemented by other similar case studies, before drawing any safer interpretative conclusions.

Bird occupancy and richness in ponderosa pine forests with contrasting forest structure and fire historyThis article is one of a selection of papers from the Special Forum on Ecological Studies in Interior Ponderosa Pine — First Findings from Blacks Mountain Interdisciplinary Research.

2008 ◽  
Vol 38 (5) ◽  
pp. 936-942 ◽  
Author(s):  
T. Luke George ◽  
Steve Zack
Keyword(s):  
Species Richness ◽  
Ponderosa Pine ◽  
Prescribed Burning ◽  
Bird Species ◽  
Bird Community ◽  
American Robin ◽  
Point Counts ◽  
Ponderosa Pine Forests ◽  
Silvicultural Treatments ◽  
Silvicultural Treatment

We compared the effects of two contrasting silvicultural treatments and prescribed fire on bird occupancy at Blacks Mountain Experimental Forest. Each silvicultural treatment was applied to two approximately 100 ha units within each of three blocks. Prescribed burning was applied to one-half of each silvicultural treatment in a split-plot design. Occupancy was estimated at eight points in each plot for 11 bird species and three foraging guilds (bark gleaners, woodpeckers, and foliage gleaners). The frequencies of species detections on the point counts were used to estimate species richness on each plot. Occupancy did not differ among treatments for any of the guilds. Four of the 11 bird species, the American robin ( Turdus migratorius L., 1766), the chipping sparrow ( Spizella passerina (Bechstein, 1798)), the white-breasted nuthatch ( Sitta carolinensis Latham, 1790), and the western tanager ( Piranga ludoviciana (A. Wilson, 1811)), showed responses to the treatments. Species richness did not differ between the silvicultural or the burn treatments. The general lack of response of the bird community to the silvicultural and burn treatments is likely a result of the relatively large size of the trees and snags retained on both silvicultural treatments, the low intensity of the prescribed burns, and the lack of a strong contrast in tree density between the silvicultural treatments.

A comparison of point counts with a new acoustic sampling method: a case study of a bird community from the montane forests of Mount Cameroon

Ostrich ◽  
2015 ◽  
Vol 86 (3) ◽  
pp. 213-220 ◽  
Author(s):  
Ondřej Sedláček ◽  
Jana Vokurková ◽  
Michal Ferenc ◽  
Eric Nana Djomo ◽  
Tomáš Albrecht ◽  
...  
Keyword(s):  
Sampling Method ◽  
Bird Community ◽  
Montane Forests ◽  
Point Counts ◽  
Mount Cameroon ◽  
Acoustic Sampling

scholarly journals Variation within the Bird Community of a Rehabilitated Urban Environment, Case of the Félix Houphouët-Boigny University Campus (Côte d'Ivoire)

2021 ◽  
Vol 9 (4) ◽  
Author(s):  
Ekoun Michael KONAN ◽  
Valérie Florence GUETONDE ◽  
Coffi Jean Magloire NIAMIEN ◽  
Kouassi Hilaire YAOKOKORE-BEIBRO
Keyword(s):  
Species Richness ◽  
Ecological Impact ◽  
Bird Species ◽  
Bird Community ◽  
University Campus ◽  
Significant Drop ◽  
Bubulcus Ibis ◽  
Total Species Richness ◽  
Ploceus Cucullatus ◽  
Total Species

In order to understand the ecological impact of the rehabilitation of the Félix Houphouët-Boigny University Campus on the bird community, a study was carried out over two months (October-November 2016). The ornithological inventory carried out by the IPA method in five different habitats identified on the campus gave a total species richness of 51 bird species of 41 genera, 27 families and 13 orders for 1374 birds, with H' = 2.93 and J = 0.74. Five species dominate the population (819 individuals, Fr = 59, 61%). These are Bubulcus ibis (9.32 %), Apus affinis (8.95 %), Corvus albus (19.94 %), Ploceus cucullatus (10.48 %), Lonchura cucullata (10.92 %). The most diversified habitat is the Habitations (26 bird species), while the most abundant is the Brush (416 individuals). Only seven species are common to all sampled habitats. Thus, 12 species observed on campus formerly could not be observed during the present study. Similarly, 18 species observed in this study were not observed in the previous study. The profound transformation of the environment following the rehabilitation has led to a slight increase in diversity but a significant drop in numbers. It is therefore important to better understand the different interactions between the components of the habitat and the various species involved. Such data would be crucial in urban planning policies.

scholarly journals Influence of Coral Architecture on Species Richness and the Hierarchical Structuration of Species Abundances in Reef Fish Communities: A Case Study in the Eastern Tropical Pacific

2019 ◽  
pp. 1-21
Author(s):  
Jean Béguinot
Keyword(s):  
Species Richness ◽  
Fish Community ◽  
Fish Communities ◽  
Total Species Richness ◽  
Species Abundances ◽  
Hierarchical Structuring ◽  
Complex Architecture ◽  
Total Species

The role of coral reef architecture on species richness and the internal structuration of the associated fish communities has already been addressed several times. The reported results, however, usually remain controversial, possibly because they are based upon incomplete field data issued from partial inventories. Indeed, incomplete samplings are almost unavoidable in practice with such species-rich communities having very uneven distribution of abundances. In this context, the numerical extrapolation of incompletely sampled communities may serve as a reliable surrogate. Accordingly, numerical extrapolations were implemented, here, to compare two fish-communities respectively associated to coral reefs that sharply differ from each-other by their topographic architectures. Both a higher total species richness and a sharper unevenness of species abundances were found to characterize the fish community associated to the more tormented reef habitat exhibiting the more complex architecture. Yet, paradoxically, the true intensity of the underlying process of hierarchical structuring of abundances proves being insensitive to the architecture of coral habitats. This apparent opposition between the unevenness pattern and the underlying structuring process results, in fact, from the additional negative dependence of abundance unevenness upon species richness.

scholarly journals Composition and structure of bird communities in vegetational gradients of Bodoquena Mountains, western Brazil

2016 ◽  
Vol 88 (1) ◽  
pp. 211-225 ◽  
Author(s):  
MAURICIO N. GODOI ◽  
FRANCO L. SOUZA ◽  
RUDI R. LAPS ◽  
DANILO B. RIBEIRO
Keyword(s):  
Vegetation Type ◽  
Bird Species ◽  
Bird Community ◽  
Bird Communities ◽  
Bird Diversity ◽  
Bird Conservation ◽  
Natural Habitats ◽  
Bird Abundance ◽  
Point Counts ◽  
Composition And Structure

ABSTRACT The informations of bird species distribution in different habitats and the structure of their communities are crucial for bird conservation. We tested the differences in composition, richness and abundance of birds in different phytophysiognomies at Bodoquena Mountains, western Brazil, and we demonstrated the variations in richness and abundance of birds between different trophic groups. Sampling was conducted between July 2011 and June 2012 in 200 point counts arranged in the study area. A total of 3350 contacts were obtained belonging to 156 bird species. Woodland savannas, seasonal forests and arboreal savannas had higher bird abundance and richness, while riparian forests, clean pastures and dirty pastures had smaller values of these parameters. The bird community was organized according to local vegetational gradient, with communities of forests, open areas and savannas, although many species occurred in more than one vegetation type. The insectivorous, omnivorous, frugivorous and gramnivorous birds composed most of the community. These data showed how important environmental heterogeneity is to bird communities. Furthermore, the presence of extensive patches of natural habitats, the small distance between these patches and the permeability of pastures, with high arboreal and shrubby cover, are indicated as important factors to maintain the bird diversity.

The Influence of Road Verges on the Use of Nearby Small Shrubland Remnants by Birds in the Central Wheatbelt of Western Australia

1997 ◽  
Vol 24 (6) ◽  
pp. 679 ◽  
Author(s):  
Daniel Fortin ◽  
Graham W. Arnold
Keyword(s):  
Species Richness ◽  
Species Turnover ◽  
Bird Species ◽  
Bird Community ◽  
Native Vegetation ◽  
Bird Abundance ◽  
Road Verge ◽  
Significant Difference ◽  
Road Verges ◽  
Number Of Individuals

In the Kellerberrin District of the Western Australian wheatbelt, about 60% of the remnants of native vegetation are smaller than 10 ha. We studied the variation in bird abundance in 13 small remnants (range 0·03–6·71 ha) of shrubland isolated in farmland by distances of 70–600 m from the nearest native vegetation, a road verge. Overall, 31 species were recorded in the remnants and nearby road verges, and species richness varied from 7 to 15 at individual sites. Regression analysis showed that the structural attributes of verges and the number of birds found in verges were more often significant predictors of variation in the number of individuals of the most common 19 species censused in remnants than were the structural attributes in the remnants themselves. The diversity of all bird species and the richness of species dependent on native vegetation decreased significantly with the distance of remnants from road verges. For a group of 10 species of small passerines, species richness, species turnover, and variation in the number of individuals between consecutive censuses all were negatively related to the distance between remnants and road verges. For five of these 10 species, there were fewer individuals in remnants than in adjacent road verges when the distance between them exceeded 110 m. However, for less-isolated remnants (≤110 m), only one species showed a significant difference in abundance. It is concluded that these small shrubland remnants are primarily used by birds moving to and from adjacent areas of native vegetation, in this case road verges. The value of small remnants of vegetation as parts of the conservation network decreases with their isolation, and is strongly linked to the use of road verges by the shrubland bird community.

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