Do fragmented coastal heathlands have habitat value to birds in eastern Australia?

2001 ◽  
Vol 28 (1) ◽  
pp. 17 ◽  
Author(s):  
Tara G. Martin ◽  
Carla P. Catterall
Keyword(s):  
Bird Species ◽  
Low Ph ◽  
Natural Vegetation ◽  
Species Assemblage ◽  
Environmental Regime ◽  
Habitat Value ◽  
Heathland Vegetation ◽  
Matrix Habitat ◽  
Eastern Australia ◽  
The Matrix

This study investigated the effects of habitat clearance and fragmentation on birds of coastal heathlands in subtropical eastern Australia. Abundance and species composition were compared among two types of cleared habitat (residential suburbs and sugar cane cropland) and four sizes of heathland remnant (1–2 ha, 5–10 ha, 20–50 ha and >500 ha) in summer and winter. Cleared land contained a distinctly different bird species assemblage from heathland remnants. Residential sites contained a distinct suite of species consistent with that described for ‘open/developed land’ habitat elsewhere in the region. In contrast, cane cropland supported very few species. Heathland remnants >500 ha contained high densities of ‘natural-vegetation-dependent’ species, whereas species of open/developed land were absent. Remnants of 1–2 ha had lowered densities of many natural-vegetation-dependent species, and a relatively high abundance of open/developed land species. Some of the avifaunal differences in the >500-ha remnants and 5–50-ha range are probably due to confounding of remnant size with habitat, resulting from selective clearing of the landscape. Most of the heathland birds were intolerant of the matrix habitat (residential and cane cropland), but tolerant of decreased remnant area, down to a threshold of about 5 ha. However, the distinctive floristic associations of heathland vegetation are dependent on an environmental regime (low nutrient, low pH, fire, in some cases inundation) that is unlikely to persist in remnants tens of hectares in size, and longer-term declines in heathland birds, are predicted.

scholarly journals Evaluating the role of contracting and expanding rainforest in initiating cycles of speciation across the Isthmus of Panama

2012 ◽  
Vol 279 (1742) ◽  
pp. 3520-3526 ◽  
Author(s):  
Brian Tilston Smith ◽  
Amei Amei ◽  
John Klicka
Keyword(s):  
Bird Species ◽  
Tropical Regions ◽  
Isthmus Of Panama ◽  
Species Pairs ◽  
The Matrix ◽  
High Species Richness ◽  
The Rich ◽  
The Tropics ◽  
The Impact

Climatic and geological changes across time are presumed to have shaped the rich biodiversity of tropical regions. However, the impact climatic drying and subsequent tropical rainforest contraction had on speciation has been controversial because of inconsistent palaeoecological and genetic data. Despite the strong interest in examining the role of climatic change on speciation in the Neotropics there has been few comparative studies, particularly, those that include non-rainforest taxa. We used bird species that inhabit humid or dry habitats that dispersed across the Panamanian Isthmus to characterize temporal and spatial patterns of speciation across this barrier. Here, we show that these two assemblages of birds exhibit temporally different speciation time patterns that supports multiple cycles of speciation. Evidence for these cycles is further corroborated by the finding that both assemblages consist of ‘young’ and ‘old’ species, despite dry habitat species pairs being geographically more distant than pairs of humid habitat species. The matrix of humid and dry habitats in the tropics not only allows for the maintenance of high species richness, but additionally this study suggests that these environments may have promoted speciation. We conclude that differentially expanding and contracting distributions of dry and humid habitats was probably an important contributor to speciation in the tropics.

scholarly journals Calcium-dependent opening of a non-specific pore in the mitochondrial inner membrane is inhibited at pH values below 7. Implications for the protective effect of low pH against chemical and hypoxic cell damage

1991 ◽  
Vol 278 (3) ◽  
pp. 715-719 ◽  
Author(s):  
A P Halestrap
Keyword(s):  
Protective Effect ◽  
Adenine Nucleotide ◽  
Cell Damage ◽  
Liver Mitochondria ◽  
Low Ph ◽  
Hypoxic Cell ◽  
Inner Membrane ◽  
Calcium Dependent ◽  
Mitochondrial Inner Membrane ◽  
The Matrix

1. The rate of opening of the Ca(2+)-induced non-specific, cyclosporin A-inhibited, pore of the mitochondrial inner membrane of rat heart and liver mitochondria at pH 6.0 was less than 10% of that at pH 7.4. 2. The effect could not be explained by inhibition of Ca2+ uptake into the mitochondria, or of the matrix peptidyl-prolyl cis-trans isomerase (PPIase), or of the Ca(2+)-induced conformational change of the adenine nucleotide translocase. 3. It is suggested that the proposed interaction of matrix PPIase with the ‘c’ conformation of the adenine nucleotide carrier in the presence of Ca2+ [Griffiths & Halestrap (1991) Biochem. J. 274, 611-614] is inhibited by low pH. 4. The relevance of this to the protective effect of low pH on hypoxic and chemical-induced cell damage is discussed.

Winter Ecological Energetics of 2 Passerine Bird Species in Temperate Wet Forest

1988 ◽  
Vol 15 (3) ◽  
pp. 319 ◽  
Author(s):  
J Haylock ◽  
a Lill
Keyword(s):  
Bird Species ◽  
Metabolic Cost ◽  
Passerine Bird ◽  
Foraging Efficiency ◽  
Energy Budgets ◽  
Similar Time ◽  
Energy Expenditures ◽  
Eastern Australia ◽  
Temperate Birds ◽  
Winter Time

Autumn and winter time-energy budgets were constructed for brown thornbills, Acanthiza pusilla, and eastern yellow robins, Eopsaltria australis, inhabiting a temperate wet forest in south-eastern Australia. Birds spent 84-88% of daylight hours foraging in both seasons, but decreased the metabolic cost of other activity in winter by spending more time on energetically inexpensive behaviours. Estimated daily energy expenditures were either seasonally constant or increased (thornbill) or decreased (robin) in winter by no nore than l0%, depending on the assumed degree of substitution for the thermoregulatory requirement. Thornbills increased foraging efficiency in winter to compensate for the reduction in absolute foraging time. Less dramatic changes in behavioural strategies were required to achieve energy balance than have been recorded for many small north temperate birds. Brown thornbills used an energetically expensive, active search foraging technique to capture small, cryptic prey at a fast rate. Yellow robins employed an inexpensive, 'sit-and-wait' strategy to capture larger, more conspicuous prey at a slower rate. Both species had similar time investments in foraging, but allocated greatly differing proportions of energy to active foraging and resting alert. These contrasting strategies offer the potential for performing several activities simultaneously in the yellow robin and for reducing foraging and vigilance investments through exploiting gregariousness in the brown thornbill.

scholarly journals An Alternative Approach for the Detection of Ethephon (2-Chlorethylphosphonic acid) Residues in Apples

2006 ◽  
Vol 1 (4) ◽  
pp. 1934578X0600100
Author(s):  
Dietmar Kröpfl ◽  
Klaus Schweiger ◽  
Franz Siegfried Wagner ◽  
Elke Prettner
Keyword(s):  
Internal Standard ◽  
Good Method ◽  
Low Ph ◽  
Measurement Precision ◽  
Direct Extraction ◽  
Selected Ion Monitoring ◽  
Method Performance ◽  
Alternative Approach ◽  
The Matrix ◽  
One Step

A rapid and simple GC/MS method to detect ethephon residues in apples is introduced using an internal standard and direct extraction of the analytes from the matrix at low pH with ethyl acetate. A one step derivatization procedure has been established using N-tert-butyldimethylsilyl-N-methyltrifluoracetamide (MTBSTFA) prior to GC/MS analysis performed in selected ion monitoring mode (SIM). Optimization of the derivatization and GC- parameters led to good method performance and measurement precision. Recovery experiments showed recovery rates ranging from 80.8 to 95.5% in the concentration range were investigated. The presented method provides significant improvements in laboratory safety, sample throughput and instrumentation cost compared with other methods to detect ethephon residues in apples.

Comparison of Avian Communities between Wet and Semiarid Habitats of Eastern Australia

1974 ◽  
Vol 1 (2) ◽  
pp. 107 ◽  
Author(s):  
J Kikkawa
Keyword(s):  
Species Diversity ◽  
Clutch Size ◽  
Bird Species ◽  
Forest Birds ◽  
Subtropical Region ◽  
Species Association ◽  
Eastern Australia ◽  
The Stability ◽  
Bird Species Diversity ◽  
Small Clutch

The composition of bird species in three distinct habitats of subtropical eastern Australia was examined in terms of the degree of species association, niche occupation and clutch size. In spite of low species diversity in the wet formations, the birds of this habitat tended to show characteristics of tropical forest birds. These included stronger association of species, relative abundance of treenesting frugivores and small clutch size. In contrast, the semiarid formations supported a greater diversity of bird species with somewhat loose species association, a large representation of graminivores, and a larger mean clutch size with greater variation. At least in the subtropical region of eastern Australia, the bird species diversity does not appear to be related to the stability of environment.

scholarly journals Multiscale effects of wetland availability and matrix composition on wetland breeding birds in Minnesota, USA

The Condor ◽  
2019 ◽  
Vol 121 (3) ◽  
Author(s):  
Sarah P Saunders ◽  
Kristin A L Hall ◽  
Nina Hill ◽  
Nicole L Michel
Keyword(s):  
Spatial Scale ◽  
Habitat Management ◽  
Spatial Scales ◽  
Bird Species ◽  
Matrix Composition ◽  
Bird Diversity ◽  
Bird Conservation ◽  
Prairie Pothole ◽  
Imperfect Detection ◽  
Matrix Habitat

Abstract The increasing intensity of wetland stressors in the Upper Midwestern United States hastens the need to understand how matrix composition influences wetland bird occurrence and abundance. The optimal spatial scale for assessing species–habitat relationships is not always apparent, but may affect inference about wetland use and suitability. We developed occupancy and abundance models, accounting for imperfect detection, for 9 wetland bird species breeding in Minnesota. We evaluated land cover associations at 3 spatial scales (12.6 ha, 50.3 ha, and 4,000 ha), quantified species-specific sensitivity to wetland availability and matrix habitat composition (agricultural and developed land covers), and assessed ecoregional variation in occupancy and abundance. Amount of wetland cover was positively associated with occupancy of 89% of species and with abundance of 67% of species, but the spatial scale of support differed among species. American Bittern (Botaurus lentiginosus), Pied-billed Grebe (Podilymbus podiceps), and Wilson’s Snipe (Gallinago delicata) in particular were negatively impacted by anthropogenic land uses within the surrounding matrix, indicating a need to shift wetland conservation planning from the site scale to the landscape scale to capture pertinent drivers of wetland bird habitat use. Mean expected occupancy across all species was greatest in the Prairie Pothole Region (PPR), suggesting that restoration efforts within this ecoregion are likely to maintain wetland bird diversity. However, given the minimal total wetland availability and predominantly agricultural matrix in the PPR, protecting wetlands and upland buffers in the Aspen Parklands or Boreal ecoregions may represent a better investment for agricultural-sensitive species such as American Bittern, Sandhill Crane (Antigone canadensis), and Wilson’s Snipe. Our modeling approach provides a multi-species framework for identifying habitat management priorities; future applications at broader spatial extents can continue to improve wetland bird conservation in a region with high rates of wetland loss and degradation.

scholarly journals Does Proximity to Wetland Shrubland Increase the Habitat Value for Shrubland Birds of Small Patches of Upland Shrubland in the Northeastern United States?

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Bill Buffum ◽  
Richard A. McKinney
Keyword(s):  
United States ◽  
Bird Species ◽  
Private Landowners ◽  
Population Declines ◽  
Northeastern United States ◽  
Bird Species Richness ◽  
Point Counts ◽  
Habitat Value ◽  
Shrubland Birds ◽  
The Impact

The loss of shrubland habitat is linked to population declines for many wildlife species, including several bird species of conservation concern. Conservation agencies in the northeastern United States encourage private landowners to clearcut patches of forest to create shrubland habitat. Many private landowners are only willing to create small clearcuts; therefore, it is important to understand how to maximize the impact of small clearcuts on bird habitat use. In this study we examined whether proximity to wetland shrubland increases the habitat value of small patches of upland shrubland. We conducted point counts at 22 sites containing small patches of upland shrubland ranging in size from 0.1 to 7 ha. Shrubland bird species richness was significantly positively correlated with the proportion of wetland shrubland habitat within 100 m of a site, and with the extent of all shrubland habitat within 100 m, but not with the proportion of upland shrubland. Occupancy modeling indicated that the size of adjacent wetland shrub patches increased occupancy at the sites for five of eight species observed with sufficient rates of detection. Our results suggest that creating clearcuts adjacent to existing areas of wetland shrubland may enhance the habitat value of the patches for shrubland birds.

scholarly journals Conserving native trees increases native bird diversity and community composition on commercial office developments

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Karen Dyson
Keyword(s):  
Community Composition ◽  
Environmental Gradients ◽  
Bird Species ◽  
Bird Community ◽  
Bird Communities ◽  
Bird Diversity ◽  
Bird Conservation ◽  
Tree Protection ◽  
Matrix Habitat ◽  
Site Use

Abstract In cities, woody vegetation provides critical shelter, nesting and foraging habitat for bird species of interest. Human actions—including development and landscaping choices—determine vegetation community composition and structure, making these choices critically important to urban bird conservation. A better understanding of how bird communities are impacted by parcel-scale actions can help guide policy and management best practices to improve matrix habitat quality and quantity. Here, I examined how bird habitat use varies along a vegetation gradient created by different development and landscaping choices. I surveyed 20 commercial office developments near Seattle in the Puget Trough region of Washington, USA selected using stratified random sampling, where I quantified bird communities and observed feeding behavior. I used GLMM and PERMANOVA models with data likelihood metrics to identify the best supported variables for bird site use, along with TITAN models to identify changes in community composition along environmental gradients. I found that measures of bird effective species richness and bird community are positively influenced by the presence of more native conifers, including the presence of a stand predating development and the height and density of native conifers. Measures of the native bird community are negatively influenced by higher non-native tree density. In contrast to prior research, top-down landscape-scale variables did not explain variation in measures of the bird community on office developments. Importantly, I found that birds are associated with the same habitat on office developments as observed elsewhere. Together, my findings suggest an important role for developers, land owners, landscape architects, and tree protection policy in bird conservation.

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