ORCID Profile
0000-0001-5356-9573
Current Organisation
NSW Department of Primary Industries
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Publisher: CSIRO Publishing
Date: 2009
DOI: 10.1071/WR08075
Abstract: 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.
Publisher: CSIRO Publishing
Date: 2010
DOI: 10.1071/AM09030
Abstract: To investigate movements and habitat selection by wild dogs we attached satellite-linked global positioning system (GPS) units to nine wild dogs (Canis lupus dingo and Canis lupus familiaris) captured in eastern Victoria in summer 2007. Units estimated locations at 30-min intervals for the first six months and then at 480-min intervals for six more months. DNA testing revealed all these wild dogs to be related. Home ranges of males were almost three times larger than those of females (males: 124.3 km2 ± 56.3, n = 4 females: 45.2 km2 ± 17.3, n = 5) and both sexes preferred subalpine grassland, shrub or woodland at the landscape and home-range scales. Wild dogs were recorded more often than expected within 25 m of roads and less often than expected within 25 m of watercourses. Wild dogs displayed higher-velocity movements with shallow turning angles (generally forwards) that connected spatial and temporal clusters comprising slower-velocity, shorter, and sharper turning movements. One wild dog travelled 230 km in 9 days before returning to its home range and another travelled 105 km in 87 days. The home-range sizes reported in this study are much larger than previously reported in south-eastern Australia. This finding, together with previous studies, suggests that the spatial scale at which wild dog management occurs needs to be reconsidered.
Publisher: Wiley
Date: 04-2006
Publisher: Springer Science and Business Media LLC
Date: 06-03-2018
Publisher: Public Library of Science (PLoS)
Date: 04-06-2015
Publisher: Elsevier BV
Date: 03-2016
Publisher: Public Library of Science (PLoS)
Date: 17-03-2014
Publisher: Canadian Science Publishing
Date: 10-2011
DOI: 10.1139/Z11-062
Abstract: In polygynous ungulates, the reproductive effort of adult males peaks during a short period in which feeding activities are sacrificed for mating activities. Hence, both fat reserves and body mass are predicted to decline markedly during this period. The decline is also predicted to be greater in fat reserves than in body mass because fat is catabolized before muscle, and to increase with the intensity of sexual selection. In contrast, no specific patterns are expected in females for which late gestation and lactation rather than mating are the energetically most demanding periods. We tested these hypotheses in two mountain ungulates of contrasting sexual size dimorphism (SSD): Himalayan tahr ( Hemitragus jemlahicus (H. Smith, 1826)) (SSD = 123%) and alpine chamois ( Rupicapra rupicapra (L., 1758)) (SSD = 26%). As expected, kidney fat declined more rapidly than body mass in adult males of both species. Kidney fat declined faster in adult male tahr compared with adult male chamois. There was no consistent pattern of changes in body mass or kidney fat in female tahr or female chamois. Our results suggest that adult males of species with strong SSD allocate more energy to mating than males of less dimorphic species.
Publisher: Wiley
Date: 29-08-2023
Abstract: Invasive deer have undesirable impacts on native ecosystems. Culling is commonly used to reduce those impacts, but is expensive and sometimes controversial. It is therefore important to robustly assess how culling reduces the impacts of invasive deer. We conducted a Before‐After Control‐Impact (BACI) experiment to determine how culling affects the impacts of invasive sambar deer Cervus unicolor in an endangered alpine peatland ecosystem in south‐eastern Australia. We established two blocks, each with four 4300‐ha experimental units, in which two units were randomly assigned to a treatment of deer culling and the other two were non‐treatment areas. Sambar deer relative abundance (faecal pellet count) and three impacts (ground degradation, pugging intensity and water turbidity) in three peatland features (peatlands, natural pools and sambar deer wallows) were surveyed before and after culling was implemented. We used four metrics to quantify the culling intensity in each treatment unit: treatment versus non‐treatment, number of deer culled on each unit, deer culled within a 500‐m buffer of impact monitoring sites and local probability of use by the cullers (1‐ha grid). The effects of culling on deer abundance and impacts were estimated using Bayesian generalised linear mixed models. Our analysis revealed that the effect of culling differed between the two experimental blocks. In one block, culling reduced deer abundance and three impacts. In the other block, culling did not reduce deer abundance but reduced three impacts and increased two impacts. The effects of culling were generally stronger when culling was estimated using finer‐scale (500‐m) than coarser‐scale (experimental unit) culling metrics. Synthesis and applications . Our study provides experimental evidence that culling invasive sambar deer reduces some of their undesirable impacts on endangered peatlands. That not all impacts were reduced by culling suggests that some effects of invasive species are slow to recover or require higher culling intensities to be reversed.
Publisher: Wiley
Date: 19-03-2004
Publisher: Wiley
Date: 02-2007
DOI: 10.1890/0012-9658(2007)88[324:TTMTOE]2.0.CO;2
Abstract: Many fundamental traits of species measured at different levels of biological organization appear to scale as a power law to body mass (M) with exponents that are multiples of 1/4. Recent work has united these relationships in a "metabolic theory of ecology" (MTE) that explains the pervasiveness of quarter-power scaling by its dependence on basal metabolic rate (B), which scales as M(0.75). Central to the MTE is theory linking the observed -0.25 scaling of maximum population growth rate (rm) and body mass to the 0.75 scaling of metabolic rate and body mass via relationships with age at first reproduction (alpha) derived from a general growth model and demographic theory. We used this theory to derive two further predictions: that age at first reproduction should scale inversely to mass-corrected basal metabolic rate alpha infinity (B/M)(-l) such that rm infinity (B/M)1. We then used phylogenetic generalized least squares and model selection methods to test the predicted scaling relationships using data from 1197 mammalian species. There was a strong phylogenetic signal in these data, highlighting the need to account for phylogeny in allometric studies. The 95% confidence intervals included, or almost included, the scaling exponent predicted by MTE for B infinity M(0.75), rm infinity M(-0.25), and rm infinity alpha(-1), but not for alpha infinity M(0.25) or the two predictions that we generated. Our results highlight a mismatch between theory and observation and imply that the observed -0.25 scaling of maximum population growth rate and body mass does not arise via the mechanism proposed in the MTE.
Publisher: CSIRO Publishing
Date: 27-10-2022
DOI: 10.1071/WR22099
Publisher: Wiley
Date: 02-03-2018
DOI: 10.1111/AEC.12575
Publisher: New Zealand Ecological Society
Date: 02-2021
Publisher: Wiley
Date: 26-11-2014
DOI: 10.1111/AVJ.12277
Publisher: Elsevier BV
Date: 08-2012
Publisher: Springer Netherlands
Date: 2009
Publisher: Wiley
Date: 19-01-2023
DOI: 10.1002/ECY.3963
Abstract: Large herbivores typically have consistently high prime‐aged adult survival and lower, more variable, juvenile, and senescent survival. Many kangaroo populations undergo greater fluctuations in density compared with other large herbivores, but age‐ and sex‐specific survival of kangaroos and their response to environmental variation remain poorly estimated. We used long‐term capture–mark–recapture data on 920 in iduals to investigate the survival component of eastern grey kangaroo ( Macropus giganteus ) population dynamics. Forage availability and population density were monitored quarterly and included as predictors of survival in Bayesian Cormack–Jolly–Seber models. Annual survival probabilities were estimated for five age classes: 0 years (juveniles), 1–2 years (subadults), 3–6 years (prime‐aged adults), 7–9 years (presenescent adults), and ≥10 years (senescent adults). Survival of juveniles varied widely during our 12‐year study, ranging from 0.07 to 0.90 for females and 0.05–0.92 for males. Subadult survival was 0.80–0.93 for females and 0.75–0.85 for males, while that of prime‐aged adults was ≥0.94 for females and ≥0.83 for males, despite large fluctuations in forage and density. The survival of presenescent adults spanned 0.86–0.93 for females and 0.60–0.86 for males. Senescent survival was variable, at 0.49–0.90 for females and 0.49–0.80 for males. Male survival was significantly lower than female survival in prime‐aged and presenescent adults, but not in other age classes. Although most of the models supported by Watanabe–Akaike Information Criterion selection included at least one environmental covariate, none of these covariates in idually had a discernible effect on survival. Temporal variability in overall survival appeared mostly due to changes in the survival of juvenile and senescent kangaroos. Kangaroo survival patterns are similar to those of ungulates, suggesting a strong role of sex–age structure on population dynamics.
Publisher: Wiley
Date: 23-05-2022
DOI: 10.1002/JWMG.22252
Abstract: Estimating the abundance and density of mountain ungulates is difficult because of rugged and remote terrain, high elevations, and rapidly changing weather. Helicopter surveys could overcome these problems, but researchers have seldom applied helicopter‐based survey methods at large spatial scales in mountain terrain. We used helicopters to count introduced Himalayan tahr ( Hemitragus jemlahicus ) at 117 plots, each of 4 km 2 , in New Zealand's Southern Alps during 2016–2019. The s ling frame was 7,844 km 2 and we located the plots at the vertices of an 8‐km grid superimposed over the s ling frame (i.e., a systematic random s ling design). We conducted 3 repeat counts at each plot during summer–autumn. We used the repeat counts to estimate tahr abundance and density, corrected for imperfect detection, using a dynamic N‐mixture model for open populations. We estimated the population of tahr in the s ling frame using design‐based, finite s ling methods and model‐based inference procedures. The mean estimated density of tahr on each plot varied from zero to 31.7 tahr/km 2 . The mean densities of tahr varied among management units, ranging from 0.3 to 10.7 tahr/km 2 , and exceeded specified intervention densities in 6 of the 7 management units. The total design‐based estimate of tahr abundance in the s ling frame was 34,500 (95% CI = 27,750–42,900), with a coefficient of variation (CV) of 0.11. The corresponding model‐based estimate of total abundance was similar (34,550, 95% CI = 30,250–38,700) but was substantially more precise (CV = 0.06) than the design‐based estimate. The precision of the estimates for the in idual management units was also better than that of the design‐based estimates, with CVs of .20 for all but 1 management unit. Our study provides a repeatable method for s ling mountain ungulates. More generally, robust estimation of abundance and density of mountain ungulates is possible by combining aerial surveys and open population models with an objective, probabilistic s ling design.
Publisher: Public Library of Science (PLoS)
Date: 10-06-2015
Publisher: Oxford University Press (OUP)
Date: 07-2004
Publisher: CSIRO Publishing
Date: 2013
DOI: 10.1071/WR13016
Abstract: Context When environmental, economic and/or social effects of wildlife are considered undesirable and need to be reduced, managers require knowledge of the effectiveness of candidate control techniques, particularly the relationship between control effort and change in abundance. Aims We evaluated the effects of control on the abundances of introduced red deer (Cervus elaphus scoticus) and sika deer (Cervus nippon) at three New Zealand forest sites (two North Island, one South Island) in an 8-year adaptive-management experiment. Methods We identified paired areas of 3600 ha at each site that were as similar as possible in geology, physical environments and forest composition and applied deer control (helicopter- and/or ground-based hunting) to a randomly selected member of each pair. The abundances of deer were monitored in each treatment and non-treatment area for up to 7 years by using faecal pellet counts on 50 randomly located transects. Key results The difference between deer abundances in the treatment and non-treatment areas was significantly negative at one site, significantly positive at one site and indistinguishable at the other site. Faecal pellet abundances declined with increasing helicopter-based hunting effort but did not change with increasing ground-based hunting effort. There was evidence that aerially sown 1080 baits used for possum control in two treatment areas reduced deer abundances. Conclusions The substantial uncertainty surrounding the relationships between deer control effort and changes in deer abundance means that managers cannot assume that the environmental, economic and/or social problems caused by deer will be alleviated with the quantum of control effort applied in the present study. Implications Reducing the abundances of deer in forests may require substantially more control effort than is currently believed.
Publisher: Wiley
Date: 06-04-2004
Publisher: Wiley
Date: 13-07-2011
DOI: 10.1002/JWMG.179
Publisher: Wiley
Date: 17-12-2011
Publisher: Wiley
Date: 16-04-2014
DOI: 10.1002/JWMG.694
Publisher: Wiley
Date: 26-07-2005
Publisher: CSIRO Publishing
Date: 10-07-2023
DOI: 10.1071/WR22128
Publisher: Wiley
Date: 24-03-2022
DOI: 10.1002/JWMG.22207
Abstract: Deer (Cervidae) are key components of many ecosystems and estimating deer abundance or density is important to understanding these roles. Many field methods have been used to estimate deer abundance and density, but the factors determining where, when, and why a method was used, and its usefulness, have not been investigated. We systematically reviewed journal articles published during 2004–2018 to evaluate spatio‐temporal trends in study objectives, methodologies, and deer abundance and density estimates, and determine how they varied with biophysical and anthropogenic attributes. We also reviewed the precision and bias of deer abundance estimation methods. We found 3,870 deer abundance and density estimates. Most estimates (58%) were for white‐tailed deer ( Odocoileus virginianus ), red deer ( Cervus elaphus ), and roe deer ( Capreolus capreolus ). The 6 key methods used to estimate abundance and density were pedestrian sign (track or fecal) counts, pedestrian direct counts, vehicular direct counts, aerial direct counts, motion‐sensitive cameras, and harvest data. There were regional differences in the use of these methods, but a general pattern was a temporal shift from using harvest data, pedestrian direct counts, and aerial direct counts to using pedestrian sign counts and motion‐sensitive cameras. Only 32% of estimates were accompanied by a measure of precision. The most precise estimates were from vehicular spotlight counts and from capture–recapture analysis of images from motion‐sensitive cameras. For aerial direct counts, capture–recapture methods provided the most precise estimates. Bias was robustly assessed in only 16 studies. Most abundance estimates were negatively biased, but capture–recapture methods were the least biased. The usefulness of deer abundance and density estimates would be substantially improved by 1) reporting key methodological details, 2) robustly assessing bias, 3) reporting the precision of estimates, 4) using methods that increase and estimate detection probability, and 5) staying up to date on new methods. The automation of image analysis using machine learning should increase the accuracy and precision of abundance estimates from direct aerial counts (visible and thermal infrared, including from unmanned aerial vehicles [drones]) and motion‐sensitive cameras, and substantially reduce the time and cost burdens of manual image analysis.
Publisher: Wiley
Date: 07-2001
Publisher: Kluwer Academic Publishers
Date: 2006
Publisher: CSIRO Publishing
Date: 06-07-2023
DOI: 10.1071/WR22129
Publisher: CSIRO Publishing
Date: 06-07-2022
DOI: 10.1071/WR21156
Publisher: Wiley
Date: 02-2006
DOI: 10.1890/05-0709
Abstract: A dominant paradigm in understanding and managing large herbivores is that, after introduction to new range or release from harvesting, the herbivore population increases to peak abundance, crashes to a lower abundance, and then increases to a carrying capacity lower than peak abundance. However, support for the paradigm has been largely anecdotal. We first developed two mathematical models to better describe irruptive dynamics. The models differed in the form of the postcrash growth toward carrying capacity: the "Caughley model" included a time lag that generated d ening oscillations, and the "Leopold model" did not. We then evaluated which of four models (theta-logistic, delayed-logistic, Leopold, and Caughley) best described the dynamics of seven ungulate populations either introduced to new range (n = 5 populations) or released from harvesting (n = 2). The dynamics of six of the populations were best described by irruptive models (two by the Leopold, one by the Caughley, and three by the delayed-logistic), and one of the populations did not display irruptive dynamics (theta-logistic model). The limited data thus support the widespread existence of irruptive dynamics, and we encourage the consideration of irruptive models in studies of large-herbivore dynamics.
Publisher: Wiley
Date: 30-09-2020
Abstract: 1. There is a global need for observation systems that deliver regular, timely data on state and trends in bio ersity, but few have been implemented, and fewer still at national scales. We describe the implementation of measurement of Essential Bio ersity Variables (EBVs) on an 8 km × 8 km grid throughout New Zealand, with multiple components of bio ersity (vegetation, birds, and some introduced mammals) measured simultaneously at each s le point. 2. Between 2011 and 2017, all public land was s led nationally (ca. 1,350 points) and some private land (ca. 500 points). Synthetic appraisals of the state of New Zealand's bio ersity, not possible previously, can be derived from the first measurement of species distribution, population abundance, and taxonomic ersity EBVs. 3. Native bird counts (all species combined) were about 2.5 times greater per s le point in natural forests and shrublands than in non‐woody ecosystems, and native bird counts exceeded those of non‐native birds across all natural forests and shrublands. 4. Non‐native plants, birds, and mammals are invasive throughout, but high‐rainfall forested regions are least invaded, and historically deforested rain shadow regions are most invaded. 5. National reporting of terrestrial bio ersity across New Zealand's public land is established and becoming normalised, in the same manner as national and international reporting of human health and education statistics. The challenge is extending coverage across all private land. Repeated measurements of these EBVs, which began in 2017, will allow defensible estimates of bio ersity trends.
Publisher: Wiley
Date: 11-11-2019
Publisher: Wiley
Date: 07-2005
Publisher: CSIRO Publishing
Date: 20-07-2023
DOI: 10.1071/WR22120
Publisher: Springer Science and Business Media LLC
Date: 14-07-2010
Publisher: Wiley
Date: 04-2003
Publisher: Wiley
Date: 20-06-2019
DOI: 10.1002/JWMG.21675
Publisher: Public Library of Science (PLoS)
Date: 11-06-2014
Publisher: Wiley
Date: 06-1999
Publisher: CSIRO Publishing
Date: 11-09-2023
DOI: 10.1071/WR23092
Publisher: Wiley
Date: 07-2016
DOI: 10.2981/WLB.00185
Abstract: Estimation of the age or age class of harvested animals is often necessary to interpret the condition and dynamics of wildlife populations. The mammalian eye lens continues to grow until death and hence the dry mass of the eye lens has commonly been used to estimate the age of mammals. The method requires the relationship between eye lens mass and age to be parameterized using in iduals of known age. However, predicting age is complicated by the curvilinear relationship between eye lens mass and age. We used frequentist and Bayesian methods to predict the ages and age classes of harvested hog deer Axis porcinus from eye lens mass. Deer were tagged as calves and harvested 4–177 months later in southeastern Australia. Lenses were extracted, fixed and oven‐dried. Of the five growth models evaluated, the Lord model best described the relationship between age and eye lens dry mass ( R 2 = 95%). The precision of age predictions obtained using the Lord model in a Bayesian mode of inference decreased with increasing eye lens dry mass, with the size of the 95% CI equaling or exceeding predicted age for hog deer 6 years. However, most predictions of hog deer age will have reasonable precision because few animals 6 years are harvested. Linear discriminant analysis had high predictive power for classifying hog deer to four widely‐used age classes (juvenile, yearling, prime‐age and senescent). The Bayesian method is recommended for inverse non‐linear prediction of age and the frequentist linear discriminant analysis method is recommended for estimating age class. We provide tables of correspondence between hog deer eye lens dry mass and predicted age and age class. Our statistical methods can be used to estimate age and age class for other mammalian species, including from other ageing techniques such as tooth eruption‐wear criteria.
Publisher: Elsevier BV
Date: 12-2014
Publisher: CSIRO Publishing
Date: 2015
DOI: 10.1071/WR15029
Abstract: Context Distance s ling is widely used to estimate the size of wildlife populations, including kangaroos. However, the performance of distance-s ling 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 s ling, a commonly used distance-s ling 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 s ling 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 % 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 s ling is a precise and accurate method for estimating eastern grey kangaroo abundance. The small negative biases that occurred when s le 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 s ling should have good precision (CV 20%) and minimal ( %) bias.
Publisher: Wiley
Date: 06-2005
Publisher: CSIRO Publishing
Date: 2012
DOI: 10.1071/WR12033
Abstract: 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 s led pre-fire) and 15 unburnt (n = 5 s led 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 bio ersity, 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.
Publisher: Wiley
Date: 05-2007
DOI: 10.2193/2005-695
Publisher: Public Library of Science (PLoS)
Date: 06-2015
Publisher: Wiley
Date: 31-01-2013
Publisher: Informa UK Limited
Date: 09-2011
Publisher: CSIRO Publishing
Date: 09-12-2022
DOI: 10.1071/WR22117
Publisher: CSIRO Publishing
Date: 11-07-2023
DOI: 10.1071/WR22118
Publisher: Wiley
Date: 13-01-2020
Publisher: Wiley
Date: 12-2020
DOI: 10.1111/ECOG.04917
Publisher: CSIRO Publishing
Date: 2006
DOI: 10.1071/WR05103
Abstract: Foxes, wild dogs, feral cats, rabbits, feral pigs, and feral goats are believed to have deleterious impacts on native bio ersity in Australia. However, although considerable resources have been expended controlling these six pest species, there are few reliable estimates of the effects of pest control on native bio ersity. We first show why reliable knowledge of the effects of pest animal control operations can be gained only by adopting proper experimental designs (i.e. treatment and non-treatment areas, replication, and random assignment of treatment and non-treatment areas) and monitoring of both the pest and bio ersity. We then review the design of 1915 pest control actions conducted with the aim of protecting native bio ersity in Australia during 1990–2003. Most (67.5%) pest control actions consisted of a single treatment area without monitoring of either the pest or bio ersity. Only 2.4% of pest control actions had one or more treatment and non-treatment areas, and very few treatment and non-treatment areas (0.3%) were randomly assigned. Replication of treatment and non-treatment areas occurred in only 1.0% of pest control actions. The field of wildlife management has been strongly criticised for its slow adoption of the tenets of experimentation to examine the effects of management actions, and our results show that this criticism applies to mammalian pest control in Australia. Until the principles of experimental design are adopted, knowledge of the effects of mammalian pest control in Australia will remain unreliable.
Publisher: CSIRO Publishing
Date: 26-05-2022
DOI: 10.1071/WR21147
Abstract: Context Of the six species of non-native deer present in Australia, the sambar deer is the largest and has been identified as a major threat to high-elevation peatlands in south-eastern Australia. However, little is known about sambar deer activity in high-elevation peatlands. Aims The aims of this study were to quantify sambar deer activity (including wallowing) seasonally and daily in response to biotic and abiotic variables, and how activity was impacted by ground-based shooting. Methods To estimate sambar deer activity, camera traps were continuously deployed for 4 years in two ~4300-ha areas in Alpine National Park, Victoria, south-eastern Australia. One area was subject to management operations using ground-based shooting to target deer and the other was not. Monthly activity of sambar deer was modelled using biotic (woody vegetation cover), abiotic (snow depth, aspect, slope, distance to water, road and peatland) and management (treatment versus non-treatment) covariates. Additional camera traps were deployed to monitor sambar deer activity at wallows. Key results Sambar deer activity decreased when snow depth increased (between July and September), and was highest in easterly and northerly aspects with dense woody vegetation close to high-elevation peatlands and roads. During our 4-year study, sambar deer activity decreased in the treatment area but increased in the non-treatment area. Sambar deer exhibited a crepuscular diel cycle, with greatest activity around sunset. Only male sambar deer were observed to wallow, with most wallowing occurring in the afternoon during October–June. Conclusions Sambar deer utilised high-elevation peatlands during October–June. Daily activity was crepuscular and was greatest in dense tree cover close to roads. Ground-based shooting reduced sambar deer activity in and around high-elevation peatlands. Implications Control operations targeting sambar deer at high elevations in south-eastern Australia should be conducted during October–June. Outside this period sambar deer appear to use lower-elevation habitats. The effectiveness of ground-based shooting could be improved by focusing this control action around sunset (when sambar deer are most active) and in places with dense vegetation close to roads and high-elevation peatlands.
Publisher: CSIRO Publishing
Date: 2006
DOI: 10.1071/WR05102
Abstract: Foxes, wild dogs, feral cats, rabbits, feral pigs and feral goats are believed to have deleterious impacts on native bio ersity in Australia. However, although considerable resources have been expended controlling these six species, little is known about national patterns and costs of control and monitoring. We therefore conducted a survey of pest-control operations undertaken by conservation-focused organisations in Australia. A total of 1306 control operations were reported, with most conducted during 1998–2003: there was little information prior to 1990. Foxes and rabbits were the most, and feral cats the least, frequently controlled pest species. The total area on which control was undertaken in 2003, the year for which most information was available, ranged from ~0.4 × 104 km2 for feral cats to ~10.7 × 104 km2 for foxes. A wide range of techniques and intensities were used to control each of the six species. The estimated cost of labour expended on control in 2003 ranged from $0.4 × 106 for feral cats to $5.3 × 106 for foxes. Monitoring of the pest or bio ersity occurred in 50–56% of control actions in which foxes, wild dogs and feral cats were targeted, but only 22–26% of control actions in which rabbits, feral pigs and feral goats were targeted. Our results are discussed in relation to previous studies of pest animal control and monitoring in Australia.
Publisher: CSIRO Publishing
Date: 2006
DOI: 10.1071/WR05029
Abstract: The principal method for estimating the abundance of bats in roosts is to count the number of bats exiting the roost at dusk (‘flyout counts’). We hypothesised that the accuracy and precision of flyout counts decrease non-linearly as the number of bats moving per unit of time increases, and that accuracy increases with observer experience. To test these hypotheses, we filmed grey-headed flying-foxes (Pteropus poliocephalus) exiting a roost in Melbourne on three consecutive evenings. The film was slowed and the number of flying-foxes flying-out in 30-s intervals was counted and assumed to be the true abundance. Thirteen other observers independently counted the number of flying-foxes flying-out in real time. We formulated our hypotheses into candidate models and compared support for these models using information-theoretic methods. Non-linear models had much greater support than linear models for all three flyouts. There was undercounting in two flyouts and overcounting in the third. There was good support for an effect of observer experience in one of the flyouts, but less support in the others. Precision declined as the true abundance increased in all three flyout counts. Our results indicate that accuracy, precision and observer effects vary with the dynamics of each flyout, and suggest that under some conditions flyout counts will often provide both inaccurate and imprecise estimates of abundance.
Publisher: CSIRO Publishing
Date: 2003
DOI: 10.1071/WR02116
Abstract: Feral goats in the 34 169 ha Egmont National Park (North Island, New Zealand) have been subject to sustained ground-based hunting with dogs since 1925. We analysed trends in hunting success from 1961 to 1999. During 1961–86 the catch per unit effort (CPUE) declined from 7 kills hunter–1 day–1 to kill hunter–1 day–1. Since 1987 the CPUE has been maintained at low levels. The key impediment to switching from a strategy of sustained control to eradication is whether or not all goats can be put at risk. We suggest that managers test this experimentally in part of the park before embarking on an eradication programme. On the basis of an empirical estimate of rm and an assumption of logistic growth, we estimated the current population to be ~1047 animals. Removing 50% or 90% of the population annually would eradicate the population in years or 12 years, respectively. Annual immigration of goats would prevent eradication under all scenarios.
Publisher: Wiley
Date: 04-2015
DOI: 10.1890/ES14-00453.1
Publisher: Wiley
Date: 07-01-2010
Publisher: CSIRO Publishing
Date: 12-12-2022
DOI: 10.1071/WR22030
Publisher: CSIRO Publishing
Date: 2016
DOI: 10.1071/WR16030
Abstract: Context Feral pigs (Sus scrofa) have a wide global distribution that includes large parts of Australia and New Zealand. There is concern about the impacts of feral pigs on above- and below-ground flora and fauna, but little is known about their habitat use and feeding activity in temperate rainforests. Aims We evaluated the importance of abiotic and biotic variables hypothesised to influence seasonal and annual feral pig habitat use and feeding activity in a montane conifer–angiosperm rainforest in Te Urewera, North Island, New Zealand. Methods We used a grid of 25 remote-camera locations to collect feral pig images in a 100-ha area during the winters and summers of 2010 and 2011. Plant composition, solar radiation and soil fertility variables were determined for each camera-image area. Multiseason, multistate occupancy models and information-theoretic methods were used to evaluate how these variables related to feral pig occupancy and feeding. Key results Feral pigs occupied more camera locations in summer than in winter, and detection probabilities increased if piglets were present and with increasing soil phosphorus (P). Piglets were detected only in summer, and their detection probability increased with increasing soil P. The probability of detecting feral pigs feeding also increased with soil P and was higher in 2010 than 2011. Conclusions Feral pigs selected locations with high soil P, probably because those sites had more food than did locations with low soil P. Mast fruiting of tawa (Beilschmiedia tawa) has been hypothesised to increase feral pig recruitment, and the higher detection probability of piglets in summer 2010 followed a heavier tawa fruit fall. Implications Our study highlighted the usefulness of camera traps and occupancy models for understanding seasonal and annual dynamics of cryptic ungulate species in remote, rugged forests, and suggests that the impacts of feral pigs will be greatest in areas of high soil P following widespread tawa masting.
Publisher: Wiley
Date: 15-06-2005
Publisher: Informa UK Limited
Date: 02-10-2014
Publisher: University of Chicago Press
Date: 06-2001
DOI: 10.1086/320626
Abstract: We investigated factors affecting the success of 14 species of ungulates introduced to New Zealand around 1851-1926. The 11 successful species had a shorter maximum life span and were introduced in greater numbers than the three unsuccessful species. Because introduction effort was confounded with other life-history traits, we examined whether independent introductions of the same species were more likely to succeed when a greater number of in iduals were introduced. For the six species with introductions that both succeeded and failed, successful introductions always involved an equal or greater number of in iduals than unsuccessful introductions of the same species. For all independent introductions, there was a highly significant relationship between the number of in iduals introduced and introduction success. When data for ungulate and bird introductions to New Zealand were combined, a variable categorizing species as ungulate or bird was a highly significant predictor of introduction success, after variation in introduction effort was controlled. For a given number of in iduals introduced, ungulates were much more likely to succeed than birds.
Publisher: Public Library of Science (PLoS)
Date: 19-09-2012
Publisher: Elsevier BV
Date: 08-2021
Publisher: Cambridge University Press (CUP)
Date: 08-2015
DOI: 10.7120/09627286.24.3.307
Abstract: Shooting is widely used to reduce the abundances of terrestrial wildlife populations, but there is concern about the animal welfare outcomes (‘humaneness’) of these programmes. Management agencies require methods for assessing the animal welfare outcomes of terrestrial wildlife shooting programmes. We identified four key issues in previous studies assessing the animal welfare outcomes of shooting programmes: (i) biased s ling strategies (ii) no direct ante mortem observations (iii) absence of quantifiable parameters for benchmarking and (iv) no evaluation of explanatory variables that may cause adverse welfare outcomes. We used methods that address these issues to assess the welfare outcomes of a European rabbit ( Oryctolagus cuniculus ) shooting programme in south-eastern Australia. An independent observer collected ante mortem (distance, timing and outcome of each shot fired) and post mortem (locations of bullet wounds) data. The ante mortem data were used to estimate three critical animal welfare parameters: apparent time to death (ATTD) instantaneous death rate (IDR) and wounding rate (WR). The post mortem data were used to evaluate the location of bullet wounds relative to the Australian national standard operating procedure (SOP). For rabbits, the mean IDR was 0.60, ATTD was 12 s and WR was 0.12. A large proportion of rabbits (0.75) were shot in the cranium or thorax, as required by the SOP. Logistic regression indicated that the proportion of rabbits wounded and missed increased with shooting distance. Hence, reducing shooting distances would increase the humaneness of European rabbit shooting programmes. Our approach enables the animal welfare outcomes of terrestrial shooting programmes to be independently quantified.
Publisher: CSIRO Publishing
Date: 2008
DOI: 10.1071/WR08042
Abstract: Effective management of sympatric mammalian herbivore populations requires an understanding of interspecific interactions. At Wilsons Promontory National Park, Victoria, sympatric native and introduced mammalian herbivores are thought to be contributing to modification of shrub-encroached Coastal Grassy Woodland. We estimated the diets of the five terrestrial mammalian herbivore species present using microhistological techniques. The diets of introduced hog deer (Axis porcinus) and native sw wallabies (Wallabia bicolor) consisted mainly of dicots. The diet of introduced European rabbits (Oryctolagus cuniculus) contained similar proportions of monocots and dicots. The diets of native eastern grey kangaroos (Macropus giganteus) and native common wombats (Vombatus ursinus) consisted mainly of monocots but kangaroos also consumed moderate amounts of dicots. Deer and wallabies consumed more native plants than did the other species and rabbits consumed more exotic plants than did all other species except kangaroos. Diet breadth was narrowest for kangaroos and broadest for sw wallabies and hog deer. Overlap in food use by the five herbivores was high, particularly between deer and wallabies, and between kangaroos and both rabbits and wombats. Our results suggest that the potential impacts of native and introduced species on the vegetation of Coastal Grassy Woodland are similar, and that the entire herbivore assemblage will need to be managed to increase fine fuel loads if fire is used as a restoration tool.
Publisher: Elsevier BV
Date: 05-2015
Publisher: Springer Science and Business Media LLC
Date: 28-01-1998
Abstract: There is anecdotal evidence that increasing densities of Himalayan tahr (Hemitragus jemlahicus) are associated with declining densities of chamois (Rupicapra rupicapra) in the Southern Alps, New Zealand. To examine this phenomenon, densities of tahr and chamois were measured at 53 sites within their sympatric range in the eastern Southern Alps during 1978-1979. In sites where only one species was present, tahr density was significantly higher than chamois density (P=0.032), probably reflecting species differences in sociality. Chamois density was higher in catchments without tahr than in those with tahr (P=0.012). Similarly, tahr density was significantly higher at sites without chamois than at those with chamois (P=0.033). Sites with both species present (termed sympatric) were significantly larger than those with only chamois or tahr (P<0.001). Following the prohibition of aerial hunting of tahr in 1983, 16 of the 17 sites where tahr and chamois were sympatric during 1978-1979 were recounted during 1991-1996. There was a 6-fold increase in the mean density of tahr between the two counts (P=0.001), whereas chamois density had declined significantly (P=0.006). Chamois persisted at only three sites, two of which had the highest chamois densities in 1978-1979. This is evidence that increasing densities of tahr exclude chamois from all but the `best' habitats. We conclude that intensive aerial hunting of tahr during 1967-1983 reduced tahr densities such that chamois could co-exist with tahr.
Publisher: CSIRO Publishing
Date: 02-05-2022
DOI: 10.1071/WR21138
Abstract: Context Little is known about wildlife harvesting by licensed recreational hunters in Australia, where both native and introduced species are hunted. It is important to understand harvest trends to assess sustainability for native species and implications for population control of introduced species. Aim The aim of this study was to analyse trends in hunter participation, activity and efficiency, and wildlife harvest, including effects of climate, in Victoria, Australia, for three game species groups: introduced deer, native waterfowl (ducks) and one native grassland species, stubble quail (Coturnix pectoralis). Methods Telephone surveys of a random s le of licenced Victorian hunters were performed annually from 2009 to 2019. Hunters were asked to quantify their hunting effort and the number of animals harvested. The respondents’ answers were analysed to estimate measures of hunter success, activity and efficiency. Bayesian modelling was applied to these data, accounting for changes over time, differences between survey periods for all licence types, and random effects for over-dispersion. The effect of climate on game bird hunter activity and harvest was estimated, as measured by the El Niño-Southern Oscillation (ENSO). Results Over 11 years, annual deer harvest (all species) increased exponentially, at a mean annual rate of 17% (95% credible interval: 14–21%), and the number of deer hunters increased at 8% (5–11%). In contrast, for ducks and stubble quail, hunter numbers remained relatively unchanged, with no evidence of consistent change to total harvests over time, unrelated to changes in environmental conditions or regulations. The annual duck harvest was influenced by ENSO and hunting regulations. The annual stubble quail harvest exhibited ‘boom-and-bust’ dynamics, with an exceptionally large harvest immediately after a La Niña season. Conclusions Long-term monitoring of harvest trends in south-eastern Australia revealed stark differences between introduced deer and native birds: harvest of deer increased rapidly whereas equivalent rates for game birds were either stable or declining. Seasonal effects had a strong influence on game bird harvest. Environmental and regulatory conditions were influential for harvest outcomes for ducks and stubble quail. Implications This study filled a key knowledge gap around managing harvesting of game species, but increased scrutiny is warranted in this field.
Publisher: CSIRO Publishing
Date: 31-07-2023
DOI: 10.1071/WR22106
Publisher: Wiley
Date: 27-01-2015
Publisher: Public Library of Science (PLoS)
Date: 13-05-2015
Publisher: Wiley
Date: 03-2006
Publisher: Wiley
Date: 14-01-2009
Publisher: Wiley
Date: 24-08-2018
Publisher: CSIRO Publishing
Date: 05-05-2022
DOI: 10.1071/WR21131
Publisher: Wiley
Date: 06-2013
DOI: 10.2981/11-098
Abstract: Monitoring the abundances of prey is important for informing the management of threatened and endangered predators. We evaluated the usefulness of faecal counts and distance s ling for monitoring the abundances of rusa deer Rusa timorensis , feral pig Sus scrofa and water buffalo Bubalus bubalis , the three key prey of the Komodo dragon Varanus komodoensis , at 11 sites on five islands in and around Komodo National Park, eastern Indonesia. We used species‐specific global detection functions and cluster sizes (i.e. multiple covariates distance s ling) to estimate densities of rusa deer and feral pig, but there were too few observations to estimate densities of water buffalo. Rusa deer densities varied from from 2.5 to 165.5 deer/km 2 with coefficients of variation (CVs) of 15‐105%. Feral pig densities varied from 0.0 to 25.2 pigs/km 2 with CVs of 25‐106%. There was a positive relationship between estimated faecal densities and estimated population densities for both rusa deer and feral pig: the form of the relationship was non‐linear for rusa deer, but there was similar support for linear and non‐linear relationships for feral pig. We found that faecal counts were more useful when ungulate densities were too low to estimate densities with distance s ling. Faecal count methods were also easier for field staff to conduct than distance s ling. Because spatial and temporal variation in ungulate density is likely to influence the population dynamics of the Komodo dragon, we recommend that annual monitoring of ungulates in and around Komodo National Park be undertaken using distance s ling and faecal counts. The relationships reported here will also be useful for managers establishing monitoring programmes for feral pig, rusa deer and water buffalo elsewhere in their native and exotic ranges.
Publisher: Wiley
Date: 28-04-2010
Publisher: Springer Science and Business Media LLC
Date: 04-08-2013
Publisher: CSIRO Publishing
Date: 2014
DOI: 10.1071/WR13195
Abstract: Context Warren ripping has been demonstrated to be an effective tool for controlling rabbit populations. However, few studies have examined factors influencing the rate at which ripped warrens are likely to be recolonised (i.e. be re-opened). Aims To examine factors influencing the recolonisation of ripped warrens by rabbits by using data collected on 555 warrens for up to 15 years following coordinated ripping programs at 12 sites in Victoria, south-eastern Australia. Methods Warren-monitoring data (number of active and inactive warren entrances) were analysed using discrete-time survival analysis to determine the effects of warren-level and site-level covariates on the recolonisation of ripped warrens. Key results Warren recolonisation was related to the distance between the ripped warren and the nearest active warren, the number of active entrances in the nearest warren, the initial number of active entrances in the ripped warren and the rabbit spotlight abundance index at the site. The probability of warren recolonisation was highest for ripped warrens within 1 km of an active warren and negligible beyond 3 km. The probability of warren recolonisation also increased by 22% for every increase in the rabbit spotlight count at the site by 10 rabbits km–1. Conclusions The recolonisation of ripped warrens was highly influenced by both the distance to, and size of, neighbouring active warrens. Larger warrens also appear to be preferentially recolonised compared with smaller warrens, suggesting that recolonisation of ripped areas may be related to habitat quality. The present results are consistent with ideas from classical metapopulation theory predicting that the rates of colonisation of vacant patches are dependent on both the proximity and size of the source population as well as the quality of habitat patches. Implications Although coordinated warren ripping programs are effective at achieving long-term control of rabbits, their efficiency at maintaining low rabbit populations can be increased by adopting an adaptive monitoring program that incorporates warren size and the spatial relationships among warrens, and using this information to better target maintenance-control activities.
Publisher: Wiley
Date: 18-12-2007
Publisher: CSIRO Publishing
Date: 2016
DOI: 10.1071/WR16023
Abstract: Context Shooting is used to reduce the abundance of kangaroo (Macropus sp.) populations in many peri-urban areas in Australia, but there is uncertainty surrounding the animal welfare outcomes of this practice. Aim We assessed the animal welfare outcomes of night shooting for peri-urban eastern grey kangaroos (Macropus giganteus). We quantified the duration of stress for: (1) shot animals (2) euthanased pouch young and (3) other animals in the same social group. Methods An independent observer collected thermal imagery data, enabling four key animal welfare parameters to be quantified: instantaneous death rate, median time to death, wounding rate and flight duration of conspecifics. The duration between pouch removal and insensibility was recorded for pouch young. Post-mortem data were recorded to confirm the location and extent of pathology from shooting. Key results Of the 136 kangaroos that were shot at, two were missed. The wounding rate was zero, with a 98% instantaneous death rate. The median time to death for the three animals not killed instantaneously was 12 s. For pouch young considered sentient, the median stress time was 4 s. Kaplan–Meier survival analysis revealed that the median flight duration of conspecifics was 5 s. Conclusions Our results indicate that night shooting produces a very short duration of stress to shot kangaroos, their pouch young and their conspecifics. Implications When compared to other wildlife shooting methods, night shooting is a humane method for culling peri-urban kangaroos.
Publisher: Wiley
Date: 25-02-2015
DOI: 10.1111/ECOG.01300
Publisher: The Royal Society
Date: 22-08-2006
Abstract: Islands are likely to differ in their susceptibility to colonization or invasion due to variation in factors that affect population persistence, including island area, climatic severity and habitat modification. We tested the importance of these factors in explaining the persistence of 164 introductions of six mammal species to 85 islands in the New Zealand archipelago using survival analysis and model selection techniques. As predicted by the theory of stochastic population growth, extinction risk was the greatest in the period immediately following introduction, declining rapidly to low probability by ca 25 years. This suggests that initially small populations were at greatest risk of extinction and that populations which survived for 25 years were likely to persist subsequently for much longer. Islands in the New Zealand archipelago become colder and windier with increasing latitude, and the probability of mammal populations persisting on islands declined steeply with increasing latitude. Hence, our results suggest that climatic suitability was an important determinant of the outcome of these invasions. The form of the relationship between latitude and persistence probability differed among species, emphasizing that the outcome of colonization attempts is species-environment specific.
Publisher: Public Library of Science (PLoS)
Date: 19-03-2015
Publisher: New Zealand Ecological Society
Date: 10-2022
Location: Australia
Location: Australia
Location: No location found
Location: No location found
Location: Australia
No related grants have been discovered for David Forsyth.