Distribution of the southern brown bandicoot (Isoodon obesulus) in the Portland region of south-western Victoria

2000 ◽  
Vol 27 (5) ◽  
pp. 539 ◽  
Author(s):  
Michael Rees ◽  
David Paull
Keyword(s):  
Local Population ◽  
Historical Records ◽  
Limited Information ◽  
Field Surveys ◽  
Potential Habitat ◽  
Specimen Collection ◽  
Eastern Australia ◽  
Spatial Isolation ◽  
Observational Bias ◽  
Western Victoria

The southern brown bandicoot (Isoodon obesulus) occurs across the periphery of southern and eastern Australia as a series of isolated regional populations. Historical records and recent surveys conducted for I. obesulus indicate that it has disappeared or decreased significantly from many parts of its former range. Vegetation clearance, habitat fragmentation, feral predators and fire have all been implicated in the decline of the species. This paper examines the distribution of I. obesulus in the Portland region of south-western Victoria. Historical records of I. obesulus were compiled from the specimen collection of Museum Victoria, the Atlas of Victorian Wildlife, Portland Field Naturalists’ Club records and anecdotal sources. Field surveys were conducted to determine the current distribution of I. obesulus in the study area based on evidence of its foraging activity. The historical records reveal limited information: most are clustered around centres of human activity, indicating observational bias. The field surveys demonstrate that I. obesulus occurs in the Portland region as a series of local populations. Each local population is associated with a patch of remnant native vegetation separated from neighbouring patches by dispersal barriers. Within these habitat remnants the occurrence of the species is sporadic. Approximately 69% of the potential habitat is managed by the Forests Service, 31% is managed by Parks Victoria, and less than 0.5% is held under other tenures. Spatial isolation of habitat remnants, fires and feral predators are the main threats to I. obesulus in the Portland region.

scholarly journals Short-term movement patterns, population estimates and breeding biology of an island endemic bird, the Tristan Thrush

2019 ◽  
Vol 27 (4) ◽  
pp. 245-252
Author(s):  
Peter G. Ryan ◽  
Ben J. Dilley ◽  
Delia Davies ◽  
Trevor Glass ◽  
Fitsum Abadi
Keyword(s):  
Total Population ◽  
Data Augmentation ◽  
Local Population ◽  
Population Estimates ◽  
Limited Information ◽  
Short Term ◽  
Main Island ◽  
Island Endemic ◽  
Core Study ◽  
Land Bird

AbstractThe Tristan Thrush Turdus eremita is the only land bird that survived human colonisation of the main island of Tristan da Cunha and is listed as “Near Threatened”. Population estimates are confounded by the thrushes’ inquisitive and gregarious nature as well as limited information on their movements. We report the first measures of nest densities on Nightingale Island: 6 nests·ha-1 in Phylica arborea woodland and 4–5 nests·ha-1 in tussock habitat, which suggests that the population is approximately double the previous estimate. At Inaccessible Island, we individually color ringed 110 thrushes over two months to track their short-term movements and estimate the local population size. Individuals moved up to 950 m along the coast, but 96% of resightings were < 100 m. A Bayesian data augmentation approach estimated that some 260 thrushes visited the core study area, a 200-m stretch of cobble and boulder beach where birds come to drink, bathe and forage. This result suggests that the population on Inaccessible Island also is substantially larger than reported previously. We estimate the total population to be 8000–15,000 Tristan Thrushes. The main need is a population estimate for the nominate subspecies on the main island of Tristan.

Messmate stringybark: bark ignitability and burning sustainability in relation to fragment dimensions, hazard score and time since fire

2017 ◽  
Vol 26 (10) ◽  
pp. 866 ◽  
Author(s):  
Tara E. Penman ◽  
Jane G. Cawson ◽  
Simon Murphy ◽  
Thomas J. Duff
Keyword(s):  
Physical Properties ◽  
Hazard Assessment ◽  
Fire Suppression ◽  
Assessment Methods ◽  
Tree Size ◽  
Fire Behaviour ◽  
Site Assessment ◽  
Field Surveys ◽  
Time Since Fire ◽  
Eastern Australia

Messmate stringybark is common in forests across south-eastern Australia. The bark of these trees is persistent and produces firebrands that contribute to house loss and the difficulty of fire suppression during wildfires. The trees typically survive fire with the amount of bark depleted. We compared two common methods to assess messmate bark fuels: (1) field-based hazard assessment, and (2) desk-based assessment using mapped time since fire. Our measurements included space-for-time field surveys and laboratory flammability tests. Although several physical properties of bark could be approximated from both assessment methods, some bark properties important to flammability were not captured. Ignitability was found to be dependent on the amount of char on bark fragments and could be predicted by the site assessment methods, whereas sustainability was dependent on bark fragment dimensions and could not be predicted by current methods. Bark fragment properties were found to be partially a function of tree size. Overall, these findings indicate that current bark assessment methods do not capture all the key bark properties that contribute to messmate bark’s flammability. Further research is warranted to improve bark assessment methods so they better reflect bark’s contribution to fire behaviour.

scholarly journals Diversity and genetic structure of mangabeira (Hancornia speciosa Gomes), a fruit species from Cerrado

2017 ◽  
Vol 38 (4Supl1) ◽  
pp. 2479
Author(s):  
Fabiano Silva Soares ◽  
Ana Aparecida Bandini Rossi ◽  
Bruna Mezzalira da Silva ◽  
Jakeline Santos Cochev ◽  
Severino De Paiva Sobrinho ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Local Population ◽  
Shannon Index ◽  
Group Method ◽  
Limited Information ◽  
Alternative Source ◽  
Economic Resource ◽  
Pair Group ◽  
Hancornia Speciosa ◽  
Issr Primers

Hancornia speciosa Gomes, popularly known as mangabeira, is a fruit tree belonging to the Apocynaceae family, native to the Brazilian Cerrado. The fruit is widely used by the local population as an alternative source of income. Limited information is available about this species, which increases the difficulty of conserving its genetic resources and exploiting mangabeira as an economic resource. The objective of this research was to evaluate the genetic diversity and genetic structure of H. speciosa from Chapada dos Guimarães. Twenty-four trees and ten inter simple sequence repeats (ISSR) primers were evaluated. Of the 57 bands obtained, 33 (57.89%) presented polymorphism. The analysis using Structure defined two different clusters (K = 2), which were consistent with the unweighted pair group method with arithmetic mean (UPGMA) clustering analysis. The number of observed alleles (Na = 1.58), number of effective alleles (Ne = 1.29), Nei’s genetic distance (He = 0.18) and Shannon index (I = 0.27) were considered low among the population. The analysis of molecular variance (AMOVA) revealed that the variability within the cluster (83.39%) was higher than among clusters (16.61%). ISSR primers proved effective for detection of genetic polymorphism in H. speciosa, and could be utilized for strategies that aim at conservation, plant breeding programs, and commercial use.

Phosphorus, sulphur, and molybdenum deficiencies in soils from eastern Australia in relation to nutrient supply and some characteristics of soil and climate.

1955 ◽  
Vol 6 (5) ◽  
pp. 673 ◽  
Author(s):  
KD McLachlan
Keyword(s):  
Phosphorus Deficiency ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Parent Material ◽  
The Other ◽  
Podzolic Soils ◽  
Sulphur Deficiency ◽  
Eastern Australia ◽  
Yield Responses ◽  
Western Victoria

Subterranean clover (Trifolium subterraneum L.) was grown on 32 virgin soils in pot cultures, and the yield responses to phosphorus, sulphur, and molybdenum were determined for each soil. The soils were collected from a wide area in eastern Australia, extending from south-western Victoria to southern Queensland. Sulphur deficiency occurred almost as frequently as phosphorus deficiency. In fact, 75 per cent. of the soils were deficient in both phosphorus and sulphur. Thirty-one per cent. were deficient in all three elements. The effect of the interaction between the elements on the occurrence and intensity of the deficiencies is shown. Molybdenum responses were obtained only after the other deficiencies had been corrected. A deficiency in one of the elements is no indication of deficiency or sufficiency of either of the other two. There was no correlation between the occurrence or intensity of the deficiencies and the geological origin of the soil parent material, the climate of the regions from which the soils were collected, or such soil characters as colour, organic matter, and texture. Responses to phosphorus were less on the black earths than on the red or yellow podzolic soils; those on the red earths were intermediate. The intensity of sulphur deficiency increased, and the intensity of molybdenum deficiency decreased, with increasing soil pH.

Population ranges of Miniopterus schreibersii (Chiroptera) in south-eastern Australia

1969 ◽  
Vol 17 (4) ◽  
pp. 665 ◽  
Author(s):  
PD Dwyer
Keyword(s):  
New South ◽  
New South Wales ◽  
South Australia ◽  
South Eastern ◽  
Navigational Cues ◽  
South Wales ◽  
Eastern Australia ◽  
North Eastern ◽  
Western Victoria ◽  
South Eastern Australia

In south-eastern Australia banding of M. schreibersii has been concentrated in four areas: north-eastern New South Wales, south-eastern New South Wales, south-eastern Victoria, and south-western Victoria and south-eastern South Australia. The present paper analyses 2083 reported movements. Only 17 of these are from one of the four areas to another with the longest movement being 810 miles. Biologically and geographically separate populations of M. schreibersii are recognized in both north-eastern and south-eastern New South Wales. Each population has its basis in dependence upon a specific nursery site which is used annually by nearly all adult females in that population. Boundaries of population ranges in New South Wales are considered to be prominent features of physiography (i.e. divides). Bats move between population ranges less often than they move within population ranges. This cannot be explained solely in terms of the distances separating roosts. Available movement records from Victoria and South Australia are consistent with the pattern described for New South Wales. Two biologically recognizable populations (i.e, different birth periods) occur in south-western Victoria and south-eastern South Australia but these may have overlapping ranges. Only one nursery colony of M. schreibersii is known from south-eastern Victoria. On present evidence it remains possible that the apparent integrity of the population associated with this nursery is merely a consequence of distance from other areas of banding activity. Detailed analyses of movements in bats may provide direct evidence as to the kinds of cues by which a given species navigates. Thus the physiographic basis described for population ranges in New South Wales is consistent with the view that M. schreibersii may orientate to waterways or divides or both. The probability that there are area differences in the subtlety or nature of navigational cues is implied by the different physiographic circumstances of south-western Victoria and south-eastern South Australia. It is suggested that knowledge of population range boundaries may aid planning of meaningful homing experiments.

Reproduction of Heterodontus portusjacksoni in Victoria, Australia: evidence of two populations and reproductive parameters for the eastern population

2007 ◽  
Vol 58 (10) ◽  
pp. 956 ◽  
Author(s):  
Javier Tovar-Ávila ◽  
Terence I. Walker ◽  
Robert W. Day
Keyword(s):  
Population Analysis ◽  
Sampling Bias ◽  
Early Spring ◽  
Egg Laying ◽  
Late Winter ◽  
Reproductive Parameters ◽  
Breeding Populations ◽  
Eastern Australia ◽  
Western Victoria ◽  
Far Eastern

Significant differences in the length–frequency composition of catch samples, mass–length relationships and length-at-maturity found between Heterodontus portusjacksoni from western and far-eastern Victoria, suggest the presence of at least two separate breeding populations off south-eastern Australia, with some mixing between these regions. In each region females attain a larger size than males, and collectively those sharks in western Victoria are smaller, present higher mass-at-length, and lower length-at-maturity than those in far-eastern Victoria. These regional differences might be a result of sampling bias, length-selective fishing mortality, environmental conditions, or genetic differences. However, tagging evidence from previous studies and the presence of two bio-geographic provinces in the region support the hypothesis of two separate breeding populations. The essential reproductive parameters for H. portusjacksoni population analysis in far-eastern Victoria were determined, using a novel method to estimate fecundity and the ovarian cycle of an egg-laying species. In this region, females have between 6 and 20 pre-ovulatory oocytes (average = 14, n = 29, standard deviation = 3.71) before the reproductive season. The species has an annual reproductive cycle correlated with water temperature, with ovulation starting during late winter to early spring and a ~6 month egg-laying period. The period from the onset of vitellogenesis to ovulation of oocytes is ~18 months.

Genetic structure and diversity of introduced eastern mosquitofish (Gambusia holbrooki) in south-eastern Australia

2012 ◽  
Vol 63 (12) ◽  
pp. 1206 ◽  
Author(s):  
Renae M. Ayres ◽  
Vincent J. Pettigrove ◽  
Ary A. Hoffmann
Keyword(s):  
Published Data ◽  
Gambusia Holbrooki ◽  
Historical Records ◽  
Genetic Structuring ◽  
South Eastern ◽  
Introduced Range ◽  
Eastern Australia ◽  
Eastern Mosquitofish ◽  
Microsatellite Diversity ◽  
South Eastern Australia

The closely related eastern mosquitofish (Gambusia holbrooki) and western mosquitofish (Gambusia affinis) have been introduced into many countries and collectively represent the most widely distributed freshwater fish in the world. We investigated genetic patterns associated with the spread of G. holbrooki in its introduced range in south-eastern Australia, by sampling 60 G. holbrooki populations (n = 1771) from major regions where G. holbrooki was initially introduced into Australia, and characterising the genetic diversity and population structure of G. holbrooki, using five polymorphic nuclear microsatellite loci and sequences from two mitochondrial genetic markers. Results were compared with published data on American and European Gambusia samples and historical records. Low microsatellite diversity and strong population genetic structuring were found within G. holbrooki in south-eastern Australia. Observed heterozygosity and allelic richness declined regionally in the order Sydney, Brisbane, Canberra, Melbourne and Adelaide. Microsatellite variation in Australia was reduced compared with native populations. Two mitochondrial DNA haplotypes of G. holbrooki were found; one was common, whereas the other was detected in one Sydney population and one Melbourne population. Cytochrome b sequence diversity was reduced compared with native and European ranges, and sequences were identical to two haplotypes previously identified. Microsatellite diversity of G. holbrooki in south-eastern Australia validates historical records of its spread, beginning north and moving south. Mitochondrial sequencing confirms that G. holbrooki is present in Australia, but the origins of Australian G. holbrooki populations remain unclear.

The economic benefits of providing shelter to reduce the mortality of twin lambs in south-western Victoria

2014 ◽  
Vol 54 (6) ◽  
pp. 773 ◽  
Author(s):  
J. M. Young ◽  
G. Saul ◽  
R. Behrendt ◽  
F. Byrne ◽  
M. McCaskill ◽  
...  
Keyword(s):  
Low Cost ◽  
Perennial Grass ◽  
Economic Value ◽  
Weather Conditions ◽  
Economic Benefits ◽  
Dual Purpose ◽  
Financial Benefits ◽  
Eastern Australia ◽  
Western Victoria ◽  
Stocking Rates

Achieving higher lamb weaning percentages by reducing lamb mortality can improve the profitability of sheep enterprises. In this paper we estimated the financial benefits from providing shelter to reduce the mortality of twin lambs in self-replacing Merino or dual-purpose Merino flock enterprises in south-west Victoria. A whole-farm bio-economic model (MIDAS) was initially used to estimate the increase in profit from reducing mortality of twin lambs and a second analysis included the costs of using perennial grass hedges to provide the shelter during lambing. The economic value of providing shelter was tested at three rates of twinning (10, 30 and 50%), three rates of mortality without shelter (70, 50 and 30%) and two levels of reduction in lamb mortality by providing shelter (25 and 50% reduction). A sensitivity analysis to wool and lamb prices, costs of establishing the grass hedges and stocking rates in the shelter area were also tested. Overall, more than 2500 scenarios were tested. Across the range of twinning rates and levels of twin mortality tested, at standard wool and meat prices, providing shelter to the dual-purpose Merino ewe flock was always profitable ($0.05 to 11.35/ewe) and the profits from providing shelter to the self-replacing Merino ewe flock were generally lower ($0.15 to $6.35/ewe). The impacts of changing wool and lamb prices depended on enterprise type, whereas the costs of establishment of the hedges or stocking rate of ewes in the hedge area during lambing had little impact on profitability. The main factor that determined the economic return from shelter was the reduction in mortality provided by the shelter but the proportion of twin-bearing ewes in the flock and the base rate of lamb mortality without shelter was also important. Overall, based on the assumptions used, we conclude that the profitability of many sheep enterprises lambing during frequent high chill weather conditions in temperate areas of south-eastern Australia could be improved by providing low cost shelter for twin-bearing Merino ewes lambing from July to September.

What makes a swamp swampy? Water regime and the botany of endangered wetlands in western Victoria

2014 ◽  
Vol 62 (6) ◽  
pp. 469 ◽  
Author(s):  
Michelle T. Casanova ◽  
I. Joan Powling
Keyword(s):  
Water Regime ◽  
Climate Changes ◽  
Negative Impact ◽  
Threshold Model ◽  
Wetland Hydrology ◽  
Temporary Wetlands ◽  
Water Plant ◽  
Eastern Australia ◽  
Impact On Biodiversity ◽  
Western Victoria

Freshwater temporary wetlands are a little-studied ecosystem worldwide. They have been recognised as critically endangered in south-eastern Australia under Australian biodiversity conservation legislation. However, little has been recorded about their hydrology, functioning or biodiversity values; i.e. the factors that make them intrinsically ‘swampy’. In this paper, we developed a simple threshold model of wetland hydrology based on historical rainfall records and calculated evaporation records matched to records and recollections of the owners of swamps, and documented water-plant and microalgal species richness. The model indicated that swamps were inundated to at least 10-cm depth in an average of 6.3 years per decade for most of the 20th century. The average dry time between inundations was 1.27 years (maximum of 4.5 years). Since 1998, the frequency of inundation appears to have decreased, and the average dry times have increased. Despite, or because of, their temporary nature, these swamps have high biodiversity values among the vegetation and the microalgae, more than has been recorded for near-by permanent wetlands. There is no evidence that a drier and warmer climate will have a negative impact on biodiversity values; however, land management is likely to be important for maintaining these systems as the climate changes.

The effects of grazing management on perennial ryegrass (Lolium perenne L.) herbage mass and persistence in south-eastern Australia

2000 ◽  
Vol 40 (2) ◽  
pp. 207 ◽  
Author(s):  
J. F. Graham ◽  
T. Prance ◽  
R. P. Thompson ◽  
D. Borg ◽  
P. Ball ◽  
...  
Keyword(s):  
Lolium Perenne ◽  
Perennial Ryegrass ◽  
South Australia ◽  
Late Summer ◽  
Grazing Management ◽  
Lolium Perenne L ◽  
Eastern Australia ◽  
Negative Effect ◽  
Western Victoria ◽  
Positive Effect

The effect of various grazing management treatments on newly sown and degraded perennial ryegrass pastures was studied at 6 different locations in the temperate high rainfall zone of southern Australia, as part of the Temperate Pasture Sustainability Key Program. The sites were located at Hamilton (2 sites, 1 grazed by cattle, 1 grazed by sheep) and Cavendish, western Victoria, Victor Harbor (Delamere), South Australia, and Ross and Parattah in Tasmania. Grazing management treatments significantly influenced the ryegrass mass and persistence of the pasture, but effects were not always consistent across sites. Autumn closure increased the perennial ryegrass content at Cavendish and Ross, as did the winter and summer closures at Ross. Spring closure increased the perennialryegrass content at Hamilton, Cavendish and Ross, but decreased it at Parattah, as did the summer closures at Parattah and Delamere. Fodder conservation decreased the ryegrass only at Parattah. At the Hamilton sheep site, and at Ross, mob stocking increased the ryegrass content, as did increased superphosphate treatments at Hamilton. Rotational grazing at Cavendish and Delamere increased the ryegrass content, as did the late spring or a late summer closure with a short autumn deferment at Cavendish and Ross, but both these treatments decreased ryegrass at Parattah. The treatments that had a negative effect at Parattah may have had a positive effect on cocksfoot at that site, creating competition for, and decreasing the ryegrass content. At most sites, treatments that included some spelling during spring to foster seed shedding, and spelling again in the following autumn to encourage germination seem to have been of benefit to the perennial ryegrass.

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