Understanding the Causes of Missed Global Positioning System Telemetry Fixes

Graves, Tabitha A.; Waller, John S.

doi:10.2193/0022-541x(2006)70[844:utcomg]2.0.co;2

Cited by 65 publications

(85 citation statements)

References 17 publications

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“…Poole and Heard (2003) reported a 76% success fix rate (15% 2D and 61% 3D) for mountain goats in mountainous terrain. Graves and Waller (2006) had a 72% success fix rate tracking bears in coniferous forest in mountainous terrain, even though the attempt-fix length of 3 min was considerably longer than the attempt-fix length of 70 s used in the present study. Sand et al (2005) realised a success fix rate of 89.8% on wolves in coniferous forest in Scandinavia.…”

Section: Gps Fixescontrasting

confidence: 56%

Use of global positioning system collars to monitor spatial-temporal movements of co-grazing goats and sheep and their common guardian dog

Gipson

Sahlu

Villaquiran

et al. 2012

Journal of Applied Animal Research

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Goats and sheep often graze together and guardian dogs are commonly used for protection from predators. The objective of this experiment was to characterise how goats, sheep and guardian dogs interact spatially when grazing the same pasture by use of global positioning system (GPS) collars as an unobtrusive means of behaviour monitoring. In 2002 and 2003, three meat goats and two sheep in a group of 12 of each species were randomly chosen and, along with a guard dog, fitted with GPS collars. Minimum distance travelled between consecutive 30-min fixes and distance between any two animals at the same fix time were calculated using spherical geometry. In 2002, the dog travelled the least between fixes during the day but more at night than either goats or sheep. However, in 2003, there was not a significant species difference in distance travelled in 24 h or during the day or night. All species travelled significantly more during day than night but none were stationary at night. Distance amongst goats and between sheep tended to be greater during day than night; distance between goats and sheep was greater than the distance amongst goats or between sheep. Hence, goats and sheep interacted as two separate entities rather than as one large herd/flock. Distance between the dog and goats was closer than between the dog and sheep, indicating a clear preference of the dog for goats that could relate to a difference in previous exposure to the two species. In summary, based on these findings protection by a guardian dog would be greater for a small group of goats than sheep and much greater than for a mixed species group. Or, with a large group of grazing animals, the number of dogs required for a certain level of protection would rank goats B sheep B mixture of goats and sheep.

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Section: Gps Fixescontrasting

confidence: 56%

Use of global positioning system collars to monitor spatial-temporal movements of co-grazing goats and sheep and their common guardian dog

Gipson

Sahlu

Villaquiran

et al. 2012

Journal of Applied Animal Research

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“…Less consistently, researchers have observed diurnal (SagerFradkin et al 2007, but see Graves & Waller 2006), seasonal (Sager-Fradkin et al 2007) and tree height or density effects (Rempel et al 1995;Rumble & Lindzey 1997;Dussault et al 1999). The effects of canopy closure on GPS errors remain predominant, reducing fix rates up to 37 per cent and location precision by 12-17 m on average (table 1).…”

Section: Types Magnitude and Causes Of Gps Errorsmentioning

confidence: 98%

Resolving issues of imprecise and habitat-biased locations in ecological analyses using GPS telemetry data

Frair

Fieberg²,

Hebblewhite

et al. 2010

Phil. Trans. R. Soc. B

336

401

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Global positioning system (GPS) technologies collect unprecedented volumes of animal location data, providing ever greater insight into animal behaviour. Despite a certain degree of inherent imprecision and bias in GPS locations, little synthesis regarding the predominant causes of these errors, their implications for ecological analysis or solutions exists. Terrestrial deployments report 37 per cent or less non-random data loss and location precision 30 m or less on average, with canopy closure having the predominant effect, and animal behaviour interacting with local habitat conditions to affect errors in unpredictable ways. Home-range estimates appear generally robust to contemporary levels of location imprecision and bias, whereas movement paths and inferences of habitat selection may readily become misleading. There is a critical need for greater understanding of the additive or compounding effects of location imprecision, fix-rate bias, and, in the case of resource selection, map error on ecological insights. Technological advances will help, but at present analysts have a suite of ad hoc statistical corrections and modelling approaches available-tools that vary greatly in analytical complexity and utility. The success of these solutions depends critically on understanding the error-inducing mechanisms, and the biggest gap in our current understanding involves species-specific behavioural effects on GPS performance.

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“…However, the differences between our study and previous ones could also relate to the differences in methods used to obtain locations for home ranges calculation. GPStelemetry allows for more accurate acquisition of location points compared to radiotelemetry and these can be obtained regardless of the researcher's presence and availability (Graves and Waller 2006). However, landscape features and the behaviour of the species, as well as environmental conditions (e.g.…”

Section: Discussionmentioning

confidence: 99%

“…However, landscape features and the behaviour of the species, as well as environmental conditions (e.g. high cloud cover), can affect GPSdata acquisition (Graves and Waller 2006). Northern quolls shelter in dens (such as rock crevices, logs, and hollow trees) that can change daily (Oakwood 2002).…”

Section: Discussionmentioning

confidence: 99%

Ecology and predator associations of the northern quoll (Dasyurus hallucatus) in the Pilbara

Hernández-Santín¹

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The northern quoll (Dasyurus hallucatus) is an endangered carnivorous marsupial in the family Dasyuridae that occurs in the northern third of Australia. It has declined throughout its range, especially in open, lowland habitats. This led to the hypothesis that rocky outcrops where it persists provide a safe haven from introduced predators and provide greater microhabitat heterogeneity associated with higher prey availability.Proposed causes of decline include introduced cane toads (Rhinella marina, which are toxic), predation by feral cats (Felis catus), foxes (Vulpes vulpes), and the dingo (Canis lupus), and habitat alteration by changes in fire regimes. The National Recovery Plan highlighted knowledge gaps relevant to the conservation of the northern quoll. These include assembling data on ecology and population status, determining factors in survival, especially introduced predators, selecting areas that can be used as refuges, and identifying and securing key populations. The Pilbara region in Western Australia is a key population currently free of invasive cane toads (a major threat).The Pilbara is a semi-arid to arid area subject to cyclones between December and ). These are dominated by spinifex (hummock) grasslands, with rugged rock outcrops, shrublands, riparian areas, and some soft (tussock) grasslands. They are subject to frequent seasonal fires, creating a mosaic of recently burnt and longer unburnt areas. The overall aim of this study was to assess the ecology of the northern quoll in the Pilbara to understand drivers of density and distribution of this endangered species, to enhance species-specific conservation efforts. I collected field data on six one-month trips over three years, predominantly using live-trapping, camera-trapping, sampling invertebrates, vegetation surveys, habitat structure, and den availability surveys.In the Pilbara, the largest mammalian predators are the introduced dingo and feral cat. The largest native mammalian carnivore is the northern quoll, which is smaller than the introduced predators but larger than the other dasyurids in the guild. In Chapter 2, I explored spatial and temporal associations among introduced predators and quolls and their associations with habitat to assess the impact of introduced predators on quolls. I found evidence that dingo control programs prevent dingoes from fulfilling their role as top predators, leading to mesopredator release of feral cats. Feral cats were associated with 3 open habitats (spinifex grasslands and recently burnt areas), and showed inverse associations to those of quolls, suggesting that quolls avoid cats in space. Quolls were positively associated with rocky habitats. In Chapter 3, I assessed spatial and temporal associations among dasyurids to understand the current role of northern quolls within their guild. I found that range contraction of northern quolls into rocky habitats prevent them from fulfilling their role as top predators across the landscape, potentially leading to mesopredator release of kalutas (Da...

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Understanding the Causes of Missed Global Positioning System Telemetry Fixes

Cited by 65 publications

References 17 publications

Use of global positioning system collars to monitor spatial-temporal movements of co-grazing goats and sheep and their common guardian dog

Use of global positioning system collars to monitor spatial-temporal movements of co-grazing goats and sheep and their common guardian dog

Resolving issues of imprecise and habitat-biased locations in ecological analyses using GPS telemetry data

Ecology and predator associations of the northern quoll (Dasyurus hallucatus) in the Pilbara

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