scholarly journals Edge effects in the avifaunal community of riparian rain-forest tracts in Tropical North Queensland

2016 ◽  
Vol 32 (4) ◽  
pp. 280-289 ◽  
Author(s):  
Montague H. C. Neate-Clegg ◽  
Emily C. Morshuis ◽  
Cristina Banks-Leite
Keyword(s):  
Species Richness ◽  
Community Composition ◽  
Edge Effects ◽  
Rain Forest ◽  
Forest Edge ◽  
Bird Communities ◽  
Forest Bird ◽  
Resource Distributions ◽  
Detection Frequency ◽  
Open Canopy

AbstractMost evidence suggests anthropogenic edges negatively affect rain-forest bird communities but little has been done to test this in Australasia. In this study, avifaunal detection frequency, species richness and community composition were compared between the edge and interior and between flat and more complex-shaped edges of riparian rain-forest tracts in Tropical North Queensland. The detection frequency and richness of guilds based on diet, foraging strata and habitat specialism were also compared. This study detected 15.1% more birds at the rain-forest edge compared with the interior but no difference in species richness. Edge shape had no effect on detection frequency or richness. Many guilds (subcanopy, closed forest, frugivorous and insectivorous species) experienced increased detection frequency at the edge relative to the interior, but for some guilds this response was reduced (habitat generalists) or reversed (understorey and mixed-flock species) along complex edges. Overall community composition was affected by edge distance but not by edge shape. Edge habitat was shorter and had more open canopy than the interior, supporting habitat-based explanations for the observed avifaunal edge effects. These results suggest generally positive edge effects in Australian rain-forest bird communities, possibly reflecting local resource distributions or a disturbance-tolerant species pool.

Bryophyte community differences between edge and interior environments in temperate rain-forest fragments of coastal British Columbia

2005 ◽  
Vol 35 (3) ◽  
pp. 580-592 ◽  
Author(s):  
Lyn K Baldwin ◽  
Gary E Bradfield
Keyword(s):  
British Columbia ◽  
Species Richness ◽  
Functional Groups ◽  
Rain Forest ◽  
Species Abundance ◽  
Forest Edge ◽  
Forest Fragments ◽  
Old Growth ◽  
Edge Zone ◽  
Temperate Rain Forest

The species richness, community composition, and abundance of bryophytes within taxonomic and functional groups were examined in relation to habitat conditions in forest edge and interior habitats of nine old-growth temperate rain-forest patches remaining after logging in the Nimpkish River Valley of Vancouver Island, British Columbia. Bryophytes were sampled at a fine scale using 0.1 m × 0.3 m microplots to examine responses of species abundance on the forest floor, downed logs, and tree bases and at a coarser scale using 10 m × 2 m belt transects to determine changes in patterns of species richness and distribution. Edge habitats, sampled to a depth of 45 m into the forest fragments, were characterized by greater windthrow disturbance. Within the edge zone, increases in the richness of clearing-affiliated functional groups were associated primarily with the location of windthrown trees and tip-up mounds, rather than with distance from the edge per se. Interior habitats had both greater abundance of old-growth-associated functional groups and total bryophyte cover. The extension of the edge zone to at least 45 m into remnant patches carries implications for minimum patch size requirements in the context of variable-retention logging of coastal temperate rain forests.

Edge effects on nest predators in two forested landscapes

2004 ◽  
Vol 82 (12) ◽  
pp. 1943-1953 ◽  
Author(s):  
Michelle L Smith
Keyword(s):  
Species Richness ◽  
Edge Effects ◽  
Spatial Scales ◽  
Forest Edge ◽  
Tamiasciurus Hudsonicus ◽  
Brood Parasite ◽  
Camera Systems ◽  
Total Species Richness ◽  
Edge Response ◽  
Nest Predators

Few studies have systematically examined edge effects on nest predators, although many invoke these processes as potential mechanisms for decreased nesting success of songbirds. Species richness and relative abundance of avian and mammalian nest predators were compared between forest edge and interior in two landscapes, Allegan State Game Area and Fort Custer Training Center (FCTC), in southwest Michigan. One avian predator, the American crow (Corvus brachyrhynchos Brehm, 1822), was more abundant at edges than forest interior at FCTC; however, other predators did not demonstrate an edge response. Abundance of the brood parasite (Molothrus ater (Boddaert, 1783)) was greater at edges in FCTC. Overall abundance was higher at FCTC in both years; however, this could not be attributed to a greater extent of fragmentation. Total species richness for both landscapes did not differ between edge and interior. Remote-camera systems captured three predation events, two involving red squirrels (Tamiasciurus hudsonicus (Erxleben, 1777)) and one involving a blue jay (Cyanocitta cristata (L., 1758)). Vegetation characteristics were similar between edge and interior sites, which suggests that vegetation structure did not influence edge response. The variability in response indicates a need to assess patterns of predator distributions through long-term studies at multiple spatial scales.

scholarly journals Marine subsidies mediate patterns in avian island biogeography

2020 ◽  
Vol 287 (1922) ◽  
pp. 20200108
Author(s):  
Debora S. Obrist ◽  
Patrick J. Hanly ◽  
Jeremiah C. Kennedy ◽  
Owen T. Fitzpatrick ◽  
Sara B. Wickham ◽  
...  
Keyword(s):  
Species Richness ◽  
Population Density ◽  
Island Biogeography ◽  
Forest Edge ◽  
Bird Communities ◽  
Negative Interaction ◽  
Breeding Bird ◽  
Island Area ◽  
Marine Subsidies ◽  
Theory Of Island Biogeography

The classical theory of island biogeography , which predicts species richness using island area and isolation, has been expanded to include contributions from marine subsidies, i.e. subsidized island biogeography (SIB) theory . We tested the effects of marine subsidies on species diversity and population density on productive temperate islands, evaluating SIB predictions previously untested at comparable scales and subsidy levels. We found that the diversity of terrestrial breeding bird communities on 91 small islands (approx. 0.0001–3 km 2 ) along the Central Coast of British Columbia, Canada were correlated most strongly with island area, but also with marine subsidies. Species richness increased and population density decreased with island area, but isolation had no measurable influence. Species richness was negatively correlated with marine subsidy, measured as forest-edge soil δ 15 N. Density, however, was higher on islands with higher marine subsidy, and a negative interaction between area and subsidy indicates that this effect is stronger on smaller islands, offering some support for SIB. Our study emphasizes how subsidies from the sea can shape diversity patterns on islands and can even exceed the importance of isolation in determining species richness and densities of terrestrial biota.

scholarly journals Patch size and vegetation structure drive changes to mixed-species flock diversity and composition across a gradient of fragment sizes in the Western Andes of Colombia

The Condor ◽  
2020 ◽  
Vol 122 (2) ◽  
Author(s):  
Harrison H Jones ◽  
Scott K Robinson
Keyword(s):  
Species Richness ◽  
Functional Diversity ◽  
Edge Effects ◽  
Vegetation Structure ◽  
Phylogenetic Diversity ◽  
Patch Size ◽  
Forest Edge ◽  
Mixed Species ◽  
Functional And Phylogenetic Diversity ◽  
Diversity Metrics

Abstract Forest fragmentation is a leading driver of biodiversity loss, yet its effects on positive species interactions remain poorly known. We examined the effects of fragmentation on mixed-species bird flocks in the Western Andes of Colombia. Using 500-m transect surveys (n = 14 transects), we sampled flocks in 8 fragments (range: 10–173 ha) and an unfragmented reference site within the same altitudinal band (1,900–2,200 m.a.s.l.) and matrix type (cattle pasture). We evaluated the relative contributions of 9 predictor variables, including patch size, distance from edge, and selective aspects of vegetation structure on the composition, size, species richness, functional diversity, and phylogenetic diversity of flocks. We found effects of both patch size and vegetation structure on flock species richness, size, and functional diversity, but no support for edge effects. Generally, flock richness and size responded differently to fragmentation than did functional and phylogenetic diversity metrics. Both flock size and richness increased with patch size, but this variable had no effect on functional and phylogenetic diversity. Flock richness and size increased in high-canopy forests with greater foliage height diversity, whereas unlogged, old-growth primary forests with large-diameter trees had lower flock richness and size, but significantly greater functional diversity. Phylogenetic diversity was not affected by patch size, edge effects, or vegetation structure. We found differences in flock composition in response to fragmentation. Richness of Furnariidae in flocks increased with increasing distance from edge and foliage height diversity, whereas that of Thraupidae and boreal migrant species increased in early successional and forest edge flocks, respectively. All flock diversity metrics differed significantly seasonally, with smaller, less diverse flocks observed in January–March than in June–August. Flocking behavior persisted in 10-ha fragments, likely because Andean flocks are “open membership” in nature, but there was extensive species turnover as forest edge and generalist species replaced forest-interior species in smaller fragments.

scholarly journals Neotropical Forest Bird Communities: A Comparison of Species Richness and Composition at Local and Regional Scales

The Condor ◽  
2007 ◽  
Vol 109 (2) ◽  
pp. 237-255 ◽  
Author(s):  
John G. Blake
Keyword(s):  
Species Richness ◽  
Spatial Scales ◽  
Geographic Distance ◽  
Bird Communities ◽  
Individual Species ◽  
Lowland Forest ◽  
Forest Bird ◽  
Neotropical Forest ◽  
Region I ◽  
The Family

Abstract Species richness and composition of Neotropical forest bird communities vary spatially at both large and small scales, but previous comparisons based on 100 ha plots have not replicated plots within a region. I sampled birds in two 100 ha plots in lowland forest of eastern Ecuador to better understand how species richness and composition vary over smaller spatial scales. Birds were sampled in February and April of 2002–2005 (only in February in 2005). Plots were approximately 1.5 km apart in predominantly terra firme forest. A total of 319 species (285 and 281 per plot) from 43 families were represented in ~16 000 detections per plot; number of species and detections per sample averaged approximately 185 and 2300, respectively. Numbers of species and detections per family were strikingly similar in the two plots, but numbers of detections of individual species often differed, likely in response to differences in habitat between the two plots. Species richness and composition were similar in many respects to comparable data from Ecuador, Peru, and French Guiana, but differed from those of Panama. Differences were most pronounced at the species level, less at the genus level, and least when comparisons were based on families. Differences among sites in South America were correlated with geographic distance at the species and genus levels, but not at the family level. Results illustrate the value of replicated plots within a region for understanding how species richness and composition can vary at small spatial scales, and highlight the importance of beta diversity for determining overall patterns of regional diversity.

scholarly journals Endangered lowland oak forest steppe remnants keep unique bird species richness in Central Hungary

2021 ◽  
Author(s):  
Gábor Ónodi ◽  
Zoltán Botta-Dukát ◽  
Dániel Winkler ◽  
Tamás Rédei
Keyword(s):  
Species Richness ◽  
Hybrid Poplar ◽  
Bird Communities ◽  
Oak Forest ◽  
Native Forest ◽  
Pedunculate Oak ◽  
Forest Bird ◽  
Retention Forestry ◽  
Arable Fields ◽  
Forest Remnants

AbstractThe biodiversity of natural or semi-natural native, old oak woodlands have high conservation importance, especially in landscapes of monocultural forest plantations and arable fields. With a wider variety of microhabitats and foraging sources, such old oak forests can provide essential habitat for native forest bird communities. We conducted a study using bird point counts to compare the forest bird communities of old pedunculate oak (Quercus robur) remnants with native and non-native plantations in central Hungary in a landscape of mostly arable fields, settlements, and monocultural plantations. Avian surveys were carried out in old oak forest remnants, middle-aged oak, white poplar (Populus alba), hybrid poplar (Populus × euramericana), black locust (Robinia pseudoacacia), and pine (Pinus spp.) plantations. Fieldwork has been carried out in nine study sites, where all six habitat types were represented (with a few exceptions), to determine total abundance, species richness, Shannon–Wiener diversity, species evenness, dominant and indicator species, and guild abundances. We found that old oak forest remnants were the most diverse habitats among the studied forest types, while hybrid poplar and pine plantations exhibited the lowest avian biodiversity. The avian guilds most sensitive to the loss of old oak forest remnants were ground foragers, bark foragers, cavity-nesters, residents, and Mediterranean migratory birds. Native habitats were more diverse than non-native plantations. Our results suggest that it is important to conserve all remaining high biodiversity old oak stands and to avoid clear-cutting of monocultural plantations in favour of practices such as mixed-species plantations, longer rotation lengths, or retention forestry.

Sign in / Sign up

Export Citation Format

Share Document