Methods for Small-Scale Surveys of Grey Kangaroo Populations

1985 ◽  
Vol 12 (2) ◽  
pp. 119 ◽  
Author(s):  
GM Coulson ◽  
JA Raines
Keyword(s):  
Population Size ◽  
Survey Methods ◽  
Faecal Pellet ◽  
Critical Conditions ◽  
Small Scale ◽  
Line Transect ◽  
Faecal Pellets ◽  
Grey Kangaroo ◽  
Pellet Counts ◽  
Transect Counts

Small-scale survey methods which have previously been applied to grey kangaroos were evaluated on a population of known size. The total population size of free-ranging eastern grey kangaroos, Macropus giganteus, on Rotamah Island in the Gippsland Lakes of Victoria was determined by a drive count. Two types of small-scale survey methods were evaluated against this total: line transect counts and faecal pellet counts. The line transect estimates were not significantly different from the known population size, and grey kangaroos appear to meet the critical conditions of the models. Counts of individual faecal pellets gave an acceptable estimate of population density, whereas counts based on pellet groups had significant positive bias.

A Study of Grey Kangaroo Density Using Pellet Counts

1981 ◽  
Vol 8 (2) ◽  
pp. 237 ◽  
Author(s):  
GJE Hill
Keyword(s):  
Faecal Pellet ◽  
Average Density ◽  
Sampling Efficiency ◽  
Faecal Pellets ◽  
Significant Variance ◽  
Pellet Group ◽  
Grey Kangaroo ◽  
Significant Difference ◽  
Pellet Counts ◽  
Pellet Density

During May and July 1978 two faecal pellet surveys were conducted to attain indices of abundance for a stable population of grey kangaroos within a 33-km2 block of state forest in southern Queensland. The study area was divided into 25-ha cells, from which approximately one-fifth were selected by random means for survey. Each cell was sampled by two parallel transects 100 m apart. Along each transect 25 regularly spaced 0.001-ha circular plots were searched for faecal pellets within particular age ranges. Results were 4634 � 19% and 5071 � 19% pellets km-2 per day respectively (Y � SE). The two surveys displayed no significant variance in estimates of average density. Preliminary surveys produced no significant difference in estimates of faecal pellet density between plots of 0.001 and 0.0003 ha. This held true for counts of pellet totals and pellet group totals. Sampling efficiency was superior for the larger plot.

Precision, accuracy and bias of walked line-transect distance sampling to estimate eastern grey kangaroo population size

2015 ◽  
Vol 42 (8) ◽  
pp. 633 ◽  
Author(s):  
Ruth Glass ◽  
David M. Forsyth ◽  
Graeme Coulson ◽  
Marco Festa-Bianchet
Keyword(s):  
Population Size ◽  
Distance Sampling ◽  
Accurate Method ◽  
Line Transect ◽  
Good Precision ◽  
Design Elements ◽  
Abundance Estimates ◽  
Grey Kangaroo ◽  
Eastern Australia ◽  
Free Ranging

Context Distance sampling is widely used to estimate the size of wildlife populations, including kangaroos. However, the performance of distance-sampling abundance estimates has seldom been evaluated for wild mammal populations of known size. Aims We evaluated the precision, accuracy, bias and interval coverage of abundance estimates from walked line-transect sampling, a commonly used distance-sampling method, for a marked free-ranging population of eastern grey kangaroos (Macropus giganteus) at Yanakie Isthmus, Wilsons Promontory National Park, south-eastern Australia. Methods In each of two study periods (November 2012 and May 2013) we first determined the true size of the uniquely marked kangaroo population by conducting 10 intensive searches of the study area. We then conducted distance sampling along six systematically spaced line transects. We walked each transect four times in November 2012 and seven times in May 2013. Data were analysed using Program DISTANCE. Key results Our intensive searches revealed that 141 and 124 collared kangaroos were present in the study area in November 2012 and May 2013, respectively. When transects were walked four or more times (i.e. ≥400 observations), maximum precision (coefficient of variation; CV of ~13%) was achieved in both survey periods. Walking transects twice (i.e. ~200 observations) produced abundance estimates with CVs of <20% in each study period. The accuracy (root mean square error) of abundance estimates varied from 1 to 13 (November 2012) and from 3 to 28 (May 2013). Bias ranged from −9% to +23%, but stabilised at between −1% and −9% when transects were walked four or more times in each study period. The 95% confidence intervals for the abundance estimates always included the true population size. Conclusions Our results indicated that walked line-transect distance sampling is a precise and accurate method for estimating eastern grey kangaroo abundance. The small negative biases that occurred when sample sizes were large were likely to be due to some animals moving outside the study area. Implications Provided that the key design elements and assumptions are met, estimates of kangaroo abundance from walked line-transect distance sampling should have good precision (CV < 20%) and minimal (<10%) bias.

Using faecal pellet counts along transects to estimate quokka (Setonix brachyurus) population density

2005 ◽  
Vol 32 (6) ◽  
pp. 503 ◽  
Author(s):  
Matt W. Hayward ◽  
Paul J. de Tores ◽  
Michael J. Dillon ◽  
Barry J. Fox ◽  
Peter B. Banks
Keyword(s):  
Population Density ◽  
Threatened Species ◽  
Faecal Pellet ◽  
Population Densities ◽  
Jarrah Forest ◽  
Linear Relationships ◽  
Pellet Counts ◽  
Transect Counts ◽  
Fox Control ◽  
Broad Scale

A study was conducted to determine the validity of using transect counts of faecal pellet groups to estimate population densities of a threatened, macropodid marsupial – the quokka (Setonix brachyurus (Quoy & Gaimard, 1830)). Mark–recapture estimates of population density were regressed against counts of faecal pellet groups at six sites with and three sites without fox control within the northern jarrah forest of Western Australia. Significant linear relationships were found between population density and pellet counts for all sites (r2 = 0.56, P < 0.02) and when all unbaited sites were excluded (r2 = 0.98, P < 0.01). We suggest that this method could be used for broad-scale monitoring of this threatened species.

An evaluation of faecal pellet counts to index rock-wallaby population size

2011 ◽  
Vol 33 (2) ◽  
pp. 221 ◽  
Author(s):  
Melinda A. Norton ◽  
Andy Sharp ◽  
Adam Marks
Keyword(s):  
Population Size ◽  
Large Degree ◽  
Faecal Pellet ◽  
Short Term ◽  
Monthly Basis ◽  
Pellet Counts ◽  
Sampling Regime ◽  
Collection Period ◽  
The Mean ◽  
Direct Counts

This study assessed the efficacy of faecal pellet counts to index population size within yellow-footed rock-wallaby (Petrogale xanthopus) colonies. One hundred 1-m2 quadrats were permanently located in each of two colonies and emptied of pellets on a monthly basis between September 1996 and August 1998. The mean number of pellets (MNP) accumulated per season (quadrats as replicates) and a mean pellet presence/absence per quadrat index (MPAP) were calculated for each colony. Other population estimates and indices (direct counts, mark–recapture and aerial surveys) were also collected at these colonies or drawn from other studies, allowing comparison with the pellet data. The trends in abundance across seasons suggested by these additional estimates and indices were an overall increase at one colony with no change at the other. While these trends were reflected by the seasonal MNP trends across the eight seasons monitored, this was less often the case for the like-season MNP comparisons. The large degree of variation in seasonal MNP data may render it unsuitable for use in such short-term like-season comparisons. The MPAP seasonal data were also found to be unreliable as an index of population size for yellow-footed rock-wallaby. In Spring 1997, one pellet collection period was missed, resulting in a combined September–October 1997 count at each colony. This increased period between pellet counts appears to have resulted in increased pellet decomposition and/or loss. This disrupted sampling regime produced a marked discrepancy in the pellet indices, particularly in the colony with more individuals and thus more pellets to lose, and highlights the importance of a structured sampling regime.

A Technique for Estimating the Numbers of Eastern Gray Kangaroos, Macropus-Giganteus, Grazing a Given Area of Pasture

1986 ◽  
Vol 13 (3) ◽  
pp. 335 ◽  
Author(s):  
RJ Perry ◽  
ML Braysher
Keyword(s):  
Decay Rate ◽  
Relative Density ◽  
Nature Reserve ◽  
Faecal Pellet ◽  
Absolute Number ◽  
Pellet Group ◽  
Potential Error ◽  
Grey Kangaroo ◽  
Pellet Counts ◽  
Pellet Density

This paper outlines a technique for estimating, by means of faecal pellet counts, the absolute number of eastern grey kangaroos, Macropus giganteus, grazing on a given area in the A.C.T. Absolute numbers were obtained by comparing relative density of pellets on the area to be assessed, with pellet density in the grey kangaroo enclosure at Tidbinbilla Nature Reserve, which has a known area and a known kangaroo population. The decay rate of pellets in three different areas did not vary significantly. The average number of pellets per pellet group was similar in all three areas, but during drought kangaroos tended to drop fewer pellets per group. However, the potential error caused by this can be avoided if the control and test areas are assessed at the same time. The problem of defining a group is eliminated by counting individual pellets rather than groups.

A Study of Habitat Preferences in the Grey Kangaroo

1981 ◽  
Vol 8 (2) ◽  
pp. 245 ◽  
Author(s):  
GJE Hill
Keyword(s):  
Cluster Analysis ◽  
Habitat Structure ◽  
Habitat Preferences ◽  
Faecal Pellet ◽  
Grey Kangaroo ◽  
Pellet Counts ◽  
And Cluster Analysis ◽  
Food Reserves ◽  
Open Woodland ◽  
Climax Forest

In a state forestry reserve in south-eastern Queensland, indices of grey kangaroo abundance were obtained from faecal pellet counts and were related to habitat structure by analysis of variance, multiple regression and cluster analysis. Of these, cluster analysis proved the most effective technique. Results identified a preference for habitats displaying an abundance of food reserves and shelter. Climax forest and open woodland type habitats were relatively little used.

Seasonal Movement PAtterns of the Eastern Grey Kangaroo in Southern Queensland

1982 ◽  
Vol 9 (3) ◽  
pp. 373 ◽  
Author(s):  
GJE Hill
Keyword(s):  
Soil Moisture ◽  
Seasonal Changes ◽  
Movement Patterns ◽  
Distribution Patterns ◽  
Faecal Pellet ◽  
Soil Moisture Storage ◽  
Seasonal Movement ◽  
Grey Kangaroo ◽  
Pellet Counts ◽  
Moisture Storage

A 2-y study was made of seasonal movement patterns of the eastern grey kangaroo, Macropus giganteus Shaw, in the Warwick district of south-eastern, and the Bollon district of south-western, Queensland. Faecal pellet counts were used to obtain indices of kangaroo usage of cleared country adjacent to cover. Kangaroos were sensitive to changes in forage status, particularly pasture phenology. As quality and quantity of forage reserves declined, animals made progressively greater use of cleared areas. This resulted in marked seasonal changes in distribution patterns. Of the variables quantified (rainfall, soil moisture storage and pasture growth), rainfall provided the best correlations with kangaroo usage of cleared country, explaining 55% (P = 0.002) of the variation in distribution at Warwick and 91% (P = 0.001) of that at Bollon.

scholarly journals Blue duiker Philantomba monticola densities in the Tsitsikamma National Park and probable factors limiting these populations

Koedoe ◽  
1991 ◽  
Vol 34 (2) ◽  
Author(s):  
N. Hanekom ◽  
V. Wilson
Keyword(s):  
National Parks ◽  
National Park ◽  
Nature Reserve ◽  
Faecal Pellet ◽  
Density Estimates ◽  
Pellet Counts ◽  
Transect Counts ◽  
Fallen Leaves ◽  
Blue Duiker ◽  
Winter Population

Numbers of blue duikers recorded on 157 and 28 variable width transect counts, done over a two year period in the Tsitsikamma Coastal National Park (TCNP) and Tsitsikamma Forest National Park (TFNP) respectively, did not differ significantly {P > 0,10) with seasons (summer v. winter). Population density estimates from transects were similar to those from game drives (0,18 v. 0,19 duikers/ha (TCNP) and 0,13 v. 0,17 duikers/ha (TFNP); P >0,10), higher than from faecal pellet counts (P < 0,10) and at least three times lower than estimates from the Kenneth Stainbank Nature Reserve and Umdoni Park in Natal. Factors contributing to the low population densities in the Tsitsikamma national parks were investigated. Twentyseven and seven percent of leopard (25) and caracal (12) scats respectively analyzed contained blue duiker remains, but predator numbers appear to be low. Forest characteristics were investigated, and results from this and other studies suggest that undergrowth cover does not markedly influence blue duiker densities in the southern Cape forests. Field and stomach analysis indicate that blue duikers feed primarily on freshly fallen leaves and fruit, and are selective foragers. In the Tsitsikamma national parks (TNPs) the frequency of occurrence of trees known to be palatable to duikers are low, while less than 45 percent of the dominant tree species fruit fully annually. This apparent scarcity of food, the low numbers of antelope species and individuals in these forests and results from duiker research in Zaire, suggest that habitat rather than predation is limiting duiker numbers in the Tsitsikamma national parks.

scholarly journals Fencing artificial waterpoints failed to influence density and distribution of red kangaroos (Macropus rufus)

2009 ◽  
Vol 36 (6) ◽  
pp. 457 ◽  
Author(s):  
Y. Fukuda ◽  
H. I. McCallum ◽  
G. C. Grigg ◽  
A. R. Pople
Keyword(s):  
Protected Areas ◽  
Food Availability ◽  
National Park ◽  
Water Sources ◽  
Spatial Context ◽  
Line Transect ◽  
Macropus Rufus ◽  
Pellet Counts ◽  
Transect Counts ◽  
Vegetation Regeneration

Provision of artificial waterpoints in Australian rangelands has resulted in an increase in the range and density of kangaroos. At high densities, kangaroos can inhibit vegetation regeneration, particularly in some protected areas where harvesting is prohibited. Fencing off waterpoints has been proposed to limit these impacts. Our aim was to determine whether fencing off waterpoints during a drought (when kangaroos would be especially water-limited) would influence the density and distribution of red kangaroos (Macropus rufus). Two waterpoints were fenced within the first 6 months of the 27-month study and a further two waterpoints were kept unfenced as controls in Idalia National Park, western Queensland. We estimated kangaroo densities around waterpoints from walked line-transect counts, and their grazing distribution from dung-pellet counts. Fencing off waterpoints failed to influence either the density or distribution up to 4 km from the waterpoints. Our results indicate that food availability, rather than the location of waterpoints, determines kangaroo distribution. Few areas in the rangelands are beyond kangaroos’ convenient reach from permanent waterpoints. Therefore, fencing off waterpoints without explicitly considering the spatial context in relation to other available water sources will fail to achieve vegetation regeneration.

Sign in / Sign up

Export Citation Format

Share Document