Landscape-scale effects of homesteads, water, and dingoes on invading chital deer in Australia’s dry tropics

Abstract Identifying landscape features and processes that facilitate the persistence of populations is particularly important for invasive mammal species, because it can focus management interventions on relatively small areas. We used camera traps to test predictions concerning the relative abundance of invading chital deer (Axis axis) on seven cattle ranches in northern Australia: that abundance of chital deer would be highest near permanent water and near homesteads, and that dingoes (Canis dingo) reduce abundance of chital deer. Distance from the nearest homestead determined deer abundance (as indexed by images per camera-day), with negligible abundance > 4 km from homesteads. In contrast, distance from homestead did not predict abundance of feral pigs (Sus scrofa), macropods, or dingoes. Abundance of chital deer also declined with increasing distance from water, as did feral pig abundance. There was no relationship between either macropod or dingo abundance and distance to water. The abundance of chital deer was unaffected by dingo abundance, but 75–100% of dingo scats collected within 1 km of homesteads contained chital deer. The high abundances of chital deer near homesteads are likely due to increased food quality or quantity, or protection from dingoes, but these hypotheses require further testing. We conclude that homesteads and permanent water are important determinants of the distribution and abundance of invasive chital deer in northern Australia (i.e., they are “invasion hubs” for this species). Our results suggest that, during the dry season, managers should survey for and attempt to control chital deer within 4 km of homesteads and within 3 km of water.

Download Full-text

Evaluation of risks for two native mammal species from feral cat baiting in monsoonal tropical northern Australia

Wildlife Research ◽

10.1071/wr17171 ◽

2018 ◽

Vol 45 (6) ◽

pp. 518 ◽

Cited By ~ 3

Author(s):

Jaime Heiniger ◽

Skye F. Cameron ◽

Graeme Gillespie

Keyword(s):

Rhodamine B ◽

Native Species ◽

Field Trials ◽

Camera Traps ◽

Northern Australia ◽

Target Species ◽

Mammal Species ◽

Feral Cat ◽

Feral Cats ◽

Dry Tropics

Context Feral cats are a significant threat to native wildlife and broad-scale control is required to reduce their impacts. Two toxic baits developed for feral cats, Curiosity® and Hisstory®, have been designed to reduce the risk of baiting to certain non-target species. These baits involve encapsulating the toxin within a hard-shelled delivery vehicle (HSDV) and placing it within a meat attractant. Native animals that chew their food more thoroughly are predicted to avoid poisoning by eating around the HSDV. This prediction has not been tested on wild native mammals in the monsoonal wet–dry tropics of the Northern Territory. Aim The aim of this research was to determine whether northern quolls (Dasyurus hallucatus) and northern brown bandicoots (Isoodon macrourus) would take feral cat baits and ingest the HSDV under natural conditions on Groote Eylandt. Methods We hand-deployed 120 non-toxic baits with a HSDV that contained a biomarker, Rhodamine B, which stains animal whiskers when ingested. The species responsible for bait removal was determined with camera traps, and HSDV ingestion was measured by evaluating Rhodamine B in whiskers removed from animals trapped after baiting. Key results During field trials, 95% of baits were removed within 5 days. Using camera-trap images, we identified the species responsible for taking baits on 65 occasions. All 65 confirmed takes were by native species, with northern quolls taking 42 baits and northern brown bandicoots taking 17. No quolls and only one bandicoot ingested the HSDV. Conclusion The use of the HSDV reduces the potential for quolls and bandicoots to ingest a toxin when they consume feral cat baits. However, high bait uptake by non-target species may reduce the efficacy of cat baiting in some areas. Implications The present study highlighted that in the monsoonal wet–dry tropics, encapsulated baits are likely to minimise poisoning risk to certain native species that would otherwise eat meat baits. However, further research may be required to evaluate risks to other non-target species. Given the threat to biodiversity from feral cats, we see it as critical to continue testing Hisstory® and Curiosity® in live-baiting trials in northern Australia.

Download Full-text

Does Dingo Predation or Buffalo Competition Regulate Feral Pig Populations in the Australian Wet-Dry Tropics? An Experimental Study.

Wildlife Research ◽

10.1071/wr9950065 ◽

1995 ◽

Vol 22 (1) ◽

pp. 65 ◽

Cited By ~ 30

Author(s):

L Corbett

Keyword(s):

Experimental Study ◽

Sus Scrofa ◽

Interference Competition ◽

Fold Increase ◽

Bubalus Bubalis ◽

Northern Australia ◽

Dry Tropics ◽

Swamp Buffalo ◽

And Control ◽

The Relationship

Dingo (Canis farniliaris dingo) predation on feral pigs (Sus scrofa) in response to experimental changes in prey populations was measured over seven years in the seasonally wet-dry tropics of northern Australia. Following the removal of feral swamp buffalo (Bubalus bubalis) from half of the 614-km*2 study area, the number of pigs doubled and there was a 3-fold increase of pig in dingo diet. The relationship between the functional response of the dingo and pig abundance was negative and significant for both the treatment and control areas. This indicated that dingoes were not regulating the pig population. Instead, dingo predation probably acted in concert with interference competition by buffalo which decreased access to critical subterranean food for pigs during the dry season and thus limited population growth in pigs.

Download Full-text

High variation in camera trap-model sensitivity for surveying mammal species in northern Australia

Wildlife Research ◽

10.1071/wr18078 ◽

2018 ◽

Vol 45 (7) ◽

pp. 578 ◽

Cited By ~ 5

Author(s):

Jaime Heiniger ◽

Graeme Gillespie

Keyword(s):

Detection Probability ◽

High Sensitivity ◽

Camera Trap ◽

Camera Traps ◽

Northern Australia ◽

Mammal Species ◽

Survey Tool ◽

Significant Difference ◽

Event Trigger ◽

The Difference

Context The use of camera traps as a wildlife survey tool has rapidly increased, and understanding the strengths and weaknesses of the technology is imperative to assess the degree to which research objectives are met. Aims We evaluated the differences in performance among three Reconyx camera-trap models, namely, a custom-modified high-sensitivity PC850, and unmodified PC850 and HC550. Methods We undertook a controlled field trial to compare the performance of the three models on Groote Eylandt, Northern Territory, by observing the ability of each model to detect the removal of a bait by native mammals. We compared variation in detecting the known event, trigger numbers, proportion of false triggers and the difference in detection probability of small to medium-sized mammals. Key results The high-sensitivity PC850 model detected bait take 75% of the time, as opposed to 33.3% and 20% for the respective unmodified models. The high-sensitivity model also increased the detection probability of the smallest mammal species from 0.09 to 0.34. However, there was no significant difference in detection probability for medium-sized mammals. Conclusions Despite the three Reconyx camera models having similar manufacturer-listed specifications, they varied substantially in their performance. The high-sensitivity model vastly improved the detection of known events and the detection probability of small mammals in northern Australia. Implications Failure to consider variation in camera-trap performance can lead to inaccurate conclusions when multiple camera models are used. Consequently, researchers should carefully consider the parameters and capabilities of camera models in study designs. Camera models and their configurations should be reported in methods, and variation in detection probabilities among different models and configurations should be incorporated into analyses.

Download Full-text

The use of regional and alluvial groundwater by riparian trees in the wet‐dry tropics of northern Australia.

Hydrological Processes ◽

10.1002/hyp.14180 ◽

2021 ◽

Author(s):

Caroline A. Canham ◽

Clément Duvert ◽

Leah S. Beesley ◽

Michael M. Douglas ◽

Samantha A. Setterfield ◽

...

Keyword(s):

Northern Australia ◽

Dry Tropics ◽

Riparian Trees ◽

Alluvial Groundwater

Download Full-text

Short-term landscape-scale effects of forest management on Peromyscus spp. mice within Missouri Ozark forests

Wildlife Society Bulletin ◽

10.2193/0091-7648(2005)33[293:sleofm]2.0.co;2 ◽

2005 ◽

Vol 33 (1) ◽

pp. 293-301 ◽

Cited By ~ 11

Author(s):

Debby K. Fantz ◽

Rochelle B. Renken

Keyword(s):

Forest Management ◽

Scale Effects ◽

Landscape Scale ◽

Short Term

Download Full-text

Fire regimes and vegetation sensitivity analysis: an example from Bradshaw Station, monsoonal northern Australia

International Journal of Wildland Fire ◽

10.1071/wf03019 ◽

2003 ◽

Vol 12 (4) ◽

pp. 349 ◽

Cited By ~ 28

Author(s):

Cameron Yates ◽

Jeremy Russell-Smith

Keyword(s):

Fire History ◽

Fire Regime ◽

Landscape Scale ◽

Fire Season ◽

Individual Species ◽

Northern Australia ◽

Sensitive Species ◽

Obligate Seeder ◽

Return Interval ◽

Noaa Avhrr

The fire-prone savannas of northern Australia comprise a matrix of mostly fire-resilient vegetation types, with embedded fire-sensitive species and communities particularly in rugged sandstone habitats. This paper addresses the assessment of fire-sensitivity at the landscape scale, drawing on detailed fire history and vegetation data assembled for one large property of 9100�km2, Bradshaw Station in the Top End of the Northern Territory, Australia. We describe (1) the contemporary fire regime for Bradshaw Station for a 10 year period; (2) the distribution and status of 'fire sensitive' vegetation; and (3) an assessment of fire-sensitivity at the landscape scale. Fire-sensitive species (FSS) were defined as obligate seeder species with minimum maturation periods of at least 3 years. The recent fire history for Bradshaw Station was derived from the interpretation of fine resolution Landsat MSS and Landsat TM imagery, supplemented with mapping from coarse resolution NOAA-AVHRR imagery where cloud had obstructed the use of Landsat images late in the fire season (typically October–November). Validation assessments of fire mapping accuracy were conducted in 1998 and 1999. On average 40% of Bradshaw burnt annually with about half of this, 22%, occurring after August (Late Dry Season LDS), and 65% of the property burnt 4 or more times, over the 10 year period; 89% of Bradshaw Station had a minimum fire return interval of less than 3 years in the study period. The derived fire seasonality, frequency and return interval data were assessed with respect to landscape units (landsystems). The largest landsystem, Pinkerton (51%, mostly sandstone) was burnt 41% on average, with about 70% burnt four times or more, over the 10 year period. Assessment of the fire-sensitivity of individual species was undertaken with reference to data assembled for 345 vegetation plots, herbarium records, and an aerial survey of the distribution of the long-lived obligate-seeder tree species Callitris intratropica. A unique list of 1310 plant species was attributed with regenerative characteristics (i.e. habit, perenniality, resprouting capability, time to seed maturation). The great majority of FSS species were restricted to rugged sandstone landforms. The approach has wider application for assessing landscape fire-sensitivity and associated landscape health in savanna landscapes in northern Australia, and elsewhere.

Download Full-text