Modelling the abundance of wildlife using field surveys and GIS: non-native sambar deer (Cervus unicolor) in the Yarra Ranges, south-eastern Australia

2009 ◽  
Vol 36 (3) ◽  
pp. 231 ◽  
Author(s):  
David M. Forsyth ◽  
Steve R. McLeod ◽  
Michael P. Scroggie ◽  
Matthew D. White
Keyword(s):  
Predictive Model ◽  
Spatial Scales ◽  
Strong Support ◽  
Geographic Information ◽  
Field Surveys ◽  
Faecal Pellets ◽  
South Eastern ◽  
Eastern Australia ◽  
Sambar Deer ◽  
South Eastern Australia

Combining abundance data collected in designed field surveys with biophysical data derived from geographic information systems is a powerful way to investigate predictors of spatial variation in the abundance of wildlife. We used such an approach to evaluate hypotheses about factors influencing the abundance of sambar deer (Cervus unicolour Kerr, 1792), a large non-native herbivore, in south-eastern Australia. We developed a spatial model for the abundance of sambar deer faecal pellets in a 3650-ha area in the Upper Yarra Ranges, Victoria. We counted the number of sambar deer faecal pellets along 100 randomly located transects and used a geographic information system to estimate biophysical variables around each transect. We formulated our hypotheses about how those variables might affect the abundance of sambar deer pellets into 22 candidate models and used the deviance information criterion to identify the ‘best’ model(s). Because five models had strong support we used model averaging to generate a predictive model. The three variables included in the predictive model were aspect (abundance of pellets declined with increasing ‘northerliness’ and increased with increasing ‘easterliness’), distance to water and elevation; the latter two variables were positively correlated and had a negative effect on the abundance of pellets. In contrast to previous models of sambar deer abundance in south-eastern Australia, our spatial predictions of the abundance of faecal pellets can be easily tested and updated. Our approach would be useful for modelling the abundances of other wildlife species at a range of spatial scales.

Modelling the factors influencing Sambar Deer (Rusa unicolor) occurrence in the wet eucalypt forests of south-eastern Australia

2020 ◽  
Author(s):  
S. Sotorra ◽  
D. Blair ◽  
W. Blanchard ◽  
D. Lindenmayer
Keyword(s):  
National Parks ◽  
Negative Binomial ◽  
Negative Binomial Regression ◽  
South Eastern ◽  
Factors Influencing ◽  
Eastern Australia ◽  
Mountain Ash ◽  
Sambar Deer ◽  
Central Highlands ◽  
South Eastern Australia

Many invasive species have had negative effects on the Australian environment, including the introduced Sambar Deer (Rusa unicolor). However, there is a paucity of information on the factors influencing the fine scale distribution and abundance patterns of Sambar Deer in south-eastern Australia. We present the results of a field survey of Sambar Deer in the Critically Endangered Mountain Ash ( Eucalyptus regnans) forests of the Central Highlands, Victoria. Our key question was: What factors influence detections of Sambar deer (based on scat counts) within the Mountain Ash forests of the Victorian Central Highlands? We surveyed 86 long-term field sites and detected a total of 245 groups of Sambar Deer pellets on 42% of these sites. Negative binomial regression modelling identified three factors associated with the occurrence of deer pellets. We recorded more pellets: (1) in 30 and 80 year old forest that remained unburned in fires that occurred in 2009, (2) on sites within closed National Parks relative to sites in State Forest, and (3) close to streams.

Development of the egg if the stick insect Didyuris violescens with particular reference to diapause

1971 ◽  
Vol 19 (2) ◽  
pp. 141 ◽  
Author(s):  
JL Readshaw ◽  
GO Bedford
Keyword(s):  
Strong Support ◽  
Stick Insect ◽  
Isolated Populations ◽  
South Eastern ◽  
Eastern Australia ◽  
Outbreak Areas ◽  
Geographic Populations ◽  
Cool Summer ◽  
Diapause Development ◽  
South Eastern Australia

The paper provides a comprehensive account of the development of the egg of the phasmatid D, violescens, a serious defoliator of Euca~ptus forests in the highlands of south-eastern Australia. The occurrence of parthenogenesis and the incidence of the two diapauses are compared in several spatially isolated populations. The observed differences are consistent with the hypothesis that D. violescens has tended to lose its capability for parthenogenesis while developing its competence for diapause as the species extended its range from subtropical to temperate regions. This hypothesis receives strong support from a recent discovery that there are at least seven genetically distinct races of D. violescens in south-eastern Australia. The influence of constant temperatures on diapause development and embryogenesis is described for several geographic populations. Irrespective of the origin of the populations, the optimum temperature for diapause development is about 2"C, and embryogenesis proceeds more rapidly as temperatures increase from a lower threshold of about 7" to 27�C. Both processes can occur simultaneously at temperatures between the two optima. The following section shows the total effect of genotype and environment on the pattern of development and hatching in the field. In the southern outbreak areas the populations are of two kinds: highland populations, in which the occurrence of the two diapauses ensures that the eggs overwinter at least twice before hatching; and foothill populations, where the absence of the first diapause means that the eggs may overwinter either once or twice before hatching, depending on when they were laid during the summer. This partly explains how a particularly cool summer can initiate the 2-year cycling of population which is the most obvious characteristic of the outbreaks of D, violescens in south-eastern Australia.

scholarly journals Patterns of demography for rocky-shore, intertidal invertebrates approaching their geographical range limits: tests of the abundant-centre hypothesis in south-eastern Australia

2010 ◽  
Vol 61 (11) ◽  
pp. 1243 ◽  
Author(s):  
Eszter Z. Hidas ◽  
David J. Ayre ◽  
Todd E. Minchinton
Keyword(s):  
Rocky Shore ◽  
Spatial Scales ◽  
Range Limits ◽  
Range Limit ◽  
Frequency Distributions ◽  
South Eastern ◽  
Size Frequency ◽  
Eastern Australia ◽  
Intertidal Invertebrates ◽  
South Eastern Australia

The abundant-centre hypothesis predicts that species' abundances peak at the centre of their geographical ranges and decline gradually towards their range limits. We tested predictions of this hypothesis for three rocky-shore, intertidal invertebrates with planktonic larvae (the whelk, Morula marginalba, the snail, Afrolittorina pyramidalis, and the barnacle, Tesseropora rosea) by quantifying their patterns of abundance and size, and inferring pulses of recruitment from size-frequency distributions, at multiple spatial scales spanning a 600-km region in south-eastern Australia and encompassing roughly the southern third of their geographical ranges. At the regional scale, abundances for all species were, as predicted, dramatically lower at their range limits. This decline was not gradual, however, because there were large variations in abundance at smaller spatial scales, and abrupt declines at the south-eastern corner of Australia. Size did not change towards the range limit for any species, but size-frequency distributions suggested a decline in the frequency of recruitment events at the range limit for T. rosea. We conclude that the abundant-centre hypothesis is not an appropriate model for abundance distributions of benthic marine invertebrates with planktonic larvae, because of the vagaries of dispersal and recruitment interacting with complex current patterns along non-uniform coastlines.

Fire exclusion and soil texture interact to influence temperate grassland flora in south-eastern Australia

2016 ◽  
Vol 64 (5) ◽  
pp. 417 ◽  
Author(s):  
Claire Moxham ◽  
Josh Dorrough ◽  
Mick Bramwell ◽  
Brad J. Farmilo
Keyword(s):  
Soil Texture ◽  
Spatial Scales ◽  
Temperate Grassland ◽  
Management Tool ◽  
Native Plant ◽  
Temperate Grasslands ◽  
South Eastern ◽  
Eastern Australia ◽  
Fire Exclusion ◽  
South Eastern Australia

Fire has a major influence on the structure and composition of temperate grasslands and woodlands. We investigated whether the impacts of fire exclusion on a temperate grassland plant community varied according to the scale of investigation and soil texture. Ten sites with known fire histories were selected along a soil texture gradient in south-eastern Australia. Floristics and ground layer attributes were investigated at small (0.25 m2) and large (100 m2) spatial scales in regularly burnt and unburnt grasslands. Fire exclusion over a 10 year period led to declines in native species diversity, richness and cover at both spatial scales and in most cases effects were consistent regardless of soil texture. However, the richness of native plant species at small scales and the cover of native plants at large scales were most negatively influenced by fire exclusion on fine textured soils. Conversely, at large scales, exotic plant richness and cover were only weakly increased by fire exclusion. Responses of eight common species were modelled and in seven of these, fire exclusion was a strong predictor of occurrence, although both positive and negative responses were observed. These results reiterate the importance of frequent fire as a management tool in temperate grasslands, but also shed light on how sites may require specific fire management regimes depending on the underlying soil texture.

Effects of large-scale high-severity fire on occupancy and abundances of an invasive large mammal in south-eastern Australia

2012 ◽  
Vol 39 (7) ◽  
pp. 555 ◽  
Author(s):  
David M. Forsyth ◽  
Andrew M. Gormley ◽  
Luke Woodford ◽  
Tony Fitzgerald
Keyword(s):  
National Park ◽  
Large Scale ◽  
Survey Methods ◽  
Large Mammal ◽  
South Eastern ◽  
High Severity ◽  
Eastern Australia ◽  
Pellet Counts ◽  
Sambar Deer ◽  
South Eastern Australia

Context Despite large mammals being an important component of many ecosystems, there is little information on the impacts of fire on large mammal populations. Aims We evaluated the effects of the large-scale high-severity ‘Black Saturday’ fires of 7 February 2009 on occupancy and abundances of an invasive large mammal, the sambar deer (Cervus unicolor), in south-eastern Australia. Methods The effects of the Black Saturday fires on the abundance of sambar deer were assessed using repeated annual counts of faecal pellets during 2007–11 in Kinglake National Park, which was burnt, and in Mount Buffalo National Park, which was not burnt. Pre-fire occupancy was modelled from data collected at 80 4-km2 cells using three survey methods. The same survey methods were used at 15 burnt (n = 9 sampled pre-fire) and 15 unburnt (n = 5 sampled pre-fire) cells 16–24 months after Black Saturday. Because multiple surveys were performed in each cell, we used a Bayesian state–space site-occupancy model to partition changes in the probability of occupancy from changes in the probability of detection. Key results Counts of sambar deer pellets increased linearly during 2007–11 in the unburnt Mount Buffalo National Park. Pellet counts also increased linearly in Kinglake National Park from 2007 to 2008, and then decreased (to zero) following Black Saturday; pellet counts increased again in 2010 and 2011. Sambar deer occupancy was weakly reduced (from 0.99 to 0.88) in burnt cells 16–24 months after Black Saturday, but was little changed in unburnt cells (from 0.99 to 0.98). Conclusions We conclude that the abundance of sambar deer was substantially reduced by the large-scale high-severity Black Saturday fires, but that most burnt habitat was reoccupied 16–24 months later. Implications There is concern about the negative impacts of invasive sambar deer on native biodiversity, particularly immediately post-fire. Our study suggests that it takes at least 8 months before sambar deer recolonise areas burnt by a large-scale high-severity fire; however, a risk-averse approach would be to act (e.g. by erecting fences or culling) sooner than that.

Temporal and spatial variation in the abundance of fish associated with the seagrass Posidonia australis in South-eastern Australia

1993 ◽  
Vol 44 (6) ◽  
pp. 881 ◽  
Author(s):  
DJ Ferrell ◽  
SE McNeill ◽  
DG Worthington ◽  
JD Bell
Keyword(s):  
Spatial Variation ◽  
Spatial Scales ◽  
Seagrass Beds ◽  
Beam Trawl ◽  
Management Decisions ◽  
Temporal And Spatial Variation ◽  
South Eastern ◽  
Eastern Australia ◽  
Temporal And Spatial ◽  
South Eastern Australia

A beam trawl was used to sample fish associated with the seagrass Posidonia australis between September 1988 and June 1990. We describe variation in abundance of fish at two spatial scales: among three seagrass beds 1-10 km apart within each of three estuaries, and among the estuaries separated by at least 100 km. Most species had significant differences in abundance among sites and estuaries that changed through time. However, many species also had consistent patterns in abundance among sites and among estuaries. For example, there were large and consistent differences in the abundance of many species among the three estuaries. Widespread changes in abundance (ie: changes that took place at all sites within an estuary or in most estuaries) were not common. The two spatial scales used in this study are also logical scales for management of seagrass habitats. The consistent differences in abundance of some fish found at both spatial scales will complicate management decisions.

scholarly journals A list of reptiles and amphibians from Box Gum Grassy Woodlands in south-eastern Australia

Check List ◽  
2013 ◽  
Vol 9 (3) ◽  
pp. 476 ◽  
Author(s):  
Geoffrey M. Kay ◽  
Damian R. Michael ◽  
Mason Crane ◽  
Sachiko Okada ◽  
Christopher MacGregor ◽  
...  
Keyword(s):  
Large Scale ◽  
Monitoring Program ◽  
Livestock Grazing ◽  
Environmental Stewardship ◽  
Field Surveys ◽  
South Eastern ◽  
Stewardship Program ◽  
Eastern Australia ◽  
Domestic Livestock ◽  
South Eastern Australia

A large-scale biodiversity monitoring program examining the response of herpetofauna to the Australian Government’s Environmental Stewardship Program is taking place in south-eastern Australia within the critically endangered Box Gum Grassy Woodland vegetation community. Field surveys involve counting reptiles in areas under Environmental Stewardship management. These “Stewardship” areas have been matched with areas managed for primary production (domestic livestock grazing). We list reptiles recorded during surveys conducted between 2010 and 2012. We recorded sixty-nine species from ten families. The list will be useful for workers interested in the zoogeographical distribution of reptiles and amphibians in fragmented agricultural woodland ecosystems.

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