A comparison of unmanned aerial vehicles (drones) and manned helicopters for monitoring macropod populations

2018 ◽  
Vol 45 (7) ◽  
pp. 586 ◽  
Author(s):  
Matthew Gentle ◽  
Neal Finch ◽  
James Speed ◽  
Anthony Pople
Keyword(s):  
Data Processing ◽  
Long Range ◽  
Best Practice ◽  
Aerial Survey ◽  
Landscape Scale ◽  
Encounter Rate ◽  
Line Transect ◽  
Unmanned Aerial Systems ◽  
Survey Technique ◽  
Helicopter Survey

Context Developments in the use of remote aircraft, or unmanned aerial systems (UAS), for ecological study have been rapid. Helicopter surveys have proven to be a reliable, repeatable method for broad-scale monitoring of harvested kangaroo populations in Australia’s rangelands, but the recent availability of long-range UAS may offer improvements in detectability and cost efficiency. Aims We aimed to test the ability of a long-range UAS (Spylite, Bluebird Aero Systems Ltd, Kadima, Israel) to survey macropod populations at a landscape scale, and validate the results against those from the current best-practice helicopter surveys. Methods Four 80-km transects in south-western Queensland were surveyed using a helicopter and UAS. Two observers, occupying the rear seats of the helicopter, recorded animals observed in distance classes perpendicular to either side of the aircraft. Continuous electro-optical (EO) or infrared (IR) video from the UAS were recorded for later processing. Animal densities were calculated using line-transect methods for both techniques. The efficiency and cost effectiveness of each survey technique were also assessed using the flight and data processing times. Key results The encounter rate for macropods during the UAS was significantly lower compared with the helicopter survey, resulting in low estimates of macropod density (3.2 versus 53.8 animals km–2 respectively). The UAS technique recorded between 2.9 and 12.7% of the macropod density observed on each transect during the helicopter survey. The helicopter surveys were less expensive and more efficient and cost effective, requiring less flight and data processing time than the UAS surveys. Conclusions Utilising long-range UAS to detect and count groups of wild animals for landscape-scale wildlife monitoring has potential, but improvements in detection and identification technology are needed to match or exceed the accuracy of the conventional aerial survey technique for kangaroos. Implications Recent advances in camera technology and methodological refinements are encouraging for aerial survey of wildlife using UAS. However, significant improvements are required to survey for kangaroos and new technology should again be tested against current benchmarks.

A Test of the Accuracy of Line and Strip Transect Estimators in Aerial Survey

1988 ◽  
Vol 15 (5) ◽  
pp. 493 ◽  
Author(s):  
J Hone
Keyword(s):  
Fourier Series ◽  
Hermite Polynomial ◽  
Aerial Survey ◽  
Survey Method ◽  
Line Transect ◽  
Accuracy And Precision ◽  
Exponential Power ◽  
Negative Exponential ◽  
Similar Accuracy ◽  
Strip Transect

The accuracy and precision of eight line transect estimators and one strip transect estimator were examined by helicopter aerial survey. Carcasses of feral pigs were counted in an area of treeless floodplain and Eucalyptus woodland. The ratio and Cox's methods, Fourier series, exponential power series, half-normal, exponential polynomial, negative exponential, hermite polynomial and hazard rate estimators gave accurate estimates. Using the survey method described, most estimators were of similar accuracy and precision, but the Fourier series estimator was the most accurate.

An Evaluation of Feral Goat Control Methods on Currawinya National Park, South-Western Queensland.

1997 ◽  
Vol 19 (2) ◽  
pp. 166 ◽  
Author(s):  
GP Edwards ◽  
TF Clancy ◽  
J Lee ◽  
J Mcdonnell
Keyword(s):  
National Park ◽  
Best Practice ◽  
Control Program ◽  
Aerial Survey ◽  
Accurate Estimate ◽  
Control Methods ◽  
Control Programs ◽  
Feral Animals ◽  
Initial Survey ◽  
Feral Goat

This study was designed to develop monitoring techniques based on aerial survey and to evaluate the effectiveness of control methods for large feral herbivores (especially goats) in the mulga woodlands. It was conducted on a study site in south-western Queensland encompassing Currawinya National Park. Two control programs were undertaken on the park: a ground-based shooting program and a two-stage live-muster and aerial culling program. Population estimates of feral goats based on 100 m strip counts from a fixed-wing aircraft were 4.6/km2 for the survey block for the initial survey with a decline to less than 2/km2 by the end of the project. It was concluded that fixed-wing aerial surveys provide an accurate estimate of the density of large feral herbivores, such as goats. The first control program, based on ground-based shooting, was of only limited success. The second control program, based on contract mustering with the aid of fixed-wing aircraft followed by aerial culling using a helicopter, was very successful in reducing the number of feral goats and other feral animals. This approach represents best practice management of feral goats in the mulga woodlands. The effect of the reduction in goat numbers on goat impact within the park is yet to be evaluated.

scholarly journals The Effect of Attenuation from Fish Shoals on Long-Range, Wide-Area Acoustic Sensing in the Ocean

2019 ◽  
Vol 11 (21) ◽  
pp. 2464 ◽  
Author(s):  
Daniel Duane ◽  
Byunggu Cho ◽  
Ankita D. Jain ◽  
Olav Rune Godø ◽  
Nicholas C. Makris
Keyword(s):  
Remote Sensing ◽  
Long Range ◽  
Cross Sections ◽  
Electromagnetic Waves ◽  
Low Frequency ◽  
Wide Area ◽  
Line Transect ◽  
Acoustic Sensing ◽  
Underwater Acoustic ◽  
Primary Means

Acoustics is the primary means of long-range and wide-area sensing in the ocean due to the severe attenuation of electromagnetic waves in seawater. While it is known that densely packed fish groups can attenuate acoustic signals during long-range propagation in an ocean waveguide, previous experimental demonstrations have been restricted to single line transect measurements of either transmission or backscatter and have not directly investigated wide-area sensing and communication issues. Here we experimentally show with wide-area sensing over 360° in the horizontal and ranges spanning many tens of kilometers that a single large fish shoal can significantly occlude acoustic sensing over entire sectors spanning more than 30° with corresponding decreases in detection ranges by roughly an order of magnitude. Such blockages can comprise significant impediments to underwater acoustic remote sensing and surveillance of underwater vehicles, marine life and geophysical phenomena as well as underwater communication. This makes it important to understand the relevant mechanisms and accurately predict attenuation from fish in long-range underwater acoustic sensing and communication. To do so, we apply an analytical theory derived from first principles for acoustic propagation and scattering through inhomogeneities in an ocean waveguide to model propagation through fish shoals. In previous experiments, either the attenuation from fish in the shoal or the scattering cross sections of fish in the shoal were measured but not both, making it impossible to directly confirm a theoretical prediction on attenuation through the shoal. Here, both measurements have been made and they experimentally confirm the waveguide theory presented. We find experimentally and theoretically that attenuation can be significant when the sensing frequency is near the resonance frequency of the shoaling fish. Negligible attenuation was observed in previous low-frequency ocean acoustic waveguide remote sensing (OAWRS) experiments because the sensing frequency was sufficiently far from the swimbladder resonance peak of the shoaling fish or the packing densities of the fish shoals were not sufficiently high. We show that common heuristic approaches that employ free space scattering assumptions for attenuation from fish groups can lead to significant errors for applications involving long-range waveguide propagation and scattering.

Corrigendum to: Distribution and relative abundance of forest duikers in Dassioko Sud Forest Reserve (coastal Côte d'Ivoire)

2018 ◽  
Vol 45 (2) ◽  
pp. 194
Author(s):  
K. A. Yao ◽  
E. A. Bitty ◽  
K. B. Kassé ◽  
Y. C. Kouakou ◽  
K. H. Yaokokoré-Beibro ◽  
...  
Keyword(s):  
Relative Abundance ◽  
Habitat Preferences ◽  
Habitat Type ◽  
Distribution Patterns ◽  
Encounter Rate ◽  
Line Transect ◽  
Habitat Types ◽  
Anthropogenic Pressures ◽  
Forest Reserve ◽  
Encounter Rates

Context Duikers play a vital role in maintaining forest ecosystems, as both seed dispersers and prey. In West Africa, duikers are also an important source of food and income; however, it is likely that some species are now being hunted at unsustainable levels. So as to contribute to duiker conservation, we used line-transect data and additional information on dung and track counts to estimate relative abundance and establish distribution patterns of forest duikers in Côte d'Ivoire's Dassioko Sud Forest Reserve (DSFR), a poorly known, remnant coastal rainforest. We also collected basic information on hunting pressure. Methods Forest duiker counts were made twice per month from July 2013 to March 2014 on six line transects of varying lengths (5.6–6.7km) and in different regions of the DSFR, representing different habitat types. The number of sightings per kilometre walked, defined as ‘encounter rate', was used to compute an index of relative abundance. We recorded all evidence of poachers and used these data to generate a poaching index (# poaching signs per kilometre) for different habitat types. Key results The DSFR has lost three of seven total forest duiker species and populations of the four remaining species are declining. Encounter rates were greatest for Philantomba maxwellii (0.46 indices km–1) and accounted for 68% of total encounters. Cephalophus niger, C. dorsalis and C. silvicultor were encountered at similar (0.07 indices km–1) but much lower rates. For all species, mean encounter rates were highest in degraded forest (0.38–0.73 indices km–1), followed by secondary (0.2–0.44 indices km–1) and primary (0.19–0.44 indices km–1) forest. Conclusions Of the four forest duiker species still present in the DSFR, the black, bay and yellow-backed duikers are the most affected by anthropogenic pressures. Duiker abundance in the DSFR varies with habitat type. This variation is apparently influenced by differences in forest structure, poaching pressure and proximity to villages. Implications The study provides baseline data for future managing of ungulate populations in the DSFR. We recommend that a biomonitoring study of duiker populations be initiated immediately to help determine population trends, investigate habitat preferences, and help curb illegal hunting activities in this important forest reserve.

Harbour porpoises (Phocoena phocoena) in north-western France: aerial survey, opportunistic sightings and strandings monitoring

2009 ◽  
Vol 89 (5) ◽  
pp. 1045-1050 ◽  
Author(s):  
J.-L. Jung ◽  
E. Stéphan ◽  
M. Louis ◽  
E. Alfonsi ◽  
C. Liret ◽  
...  
Keyword(s):  
North Sea ◽  
Aerial Survey ◽  
Harbour Porpoise ◽  
Shallow Waters ◽  
Encounter Rate ◽  
English Channel ◽  
Phocoena Phocoena ◽  
The North ◽  
The North Sea ◽  
North Western

The harbour porpoise (Phocoena phocoena) is one of the common small cetaceans of European waters. This discreet and undemonstrative species is strongly represented throughout the cold waters of the northern hemisphere, and is the most abundant cetacean in the North Sea. In the last few years, some observations and studies indicate a shift of harbour porpoise distribution in European waters, from northern regions of the North Sea to the southern North Sea, English Channel and Celtic Sea. This shift may include a comeback around the coasts of France. Harbour porpoises inhabit shelf-waters and are often observed in shallow waters, conditions offered for instance by the coasts of Brittany in north-western France. We used opportunistic sightings, aerial survey and a ten-year strandings database to study the presence of harbour porpoises along the coasts of Brittany. Opportunistic sightings made by non-specialists did not confirm a strong presence of harbour porpoises along the Brittany coasts, most probably because of the undemonstrative behaviour of this cetacean. However, aerial survey and stranding analysis indicate that harbour porpoises have become natural inhabitants of the Brittany coasts once more: 68.6% of cetacean school sightings made during a 1578 km aerial survey of the Brittany coasts concerned harbour porpoises, with an encounter rate of 1.5 individuals per 100 km that peaked to 5.8 per 100 km to the top of the shallow waters of the south-western Western English Channel. The number of harbour porpoise strandings increased each year from 1997 to 2007, making a total of 135 along the coasts of Brittany. Other cetaceans did not show such an increase during the same period. Strandings of harbour porpoises were also characterized by an apparent increase as a proportion in relation to all the cetacean strandings during the months of September to January, by a marked impact of by-catch during winter, and by an almost total absence of stranded calves. The comeback of the harbour porpoise along Brittany coasts is clearly confirmed by our data, and a stable population seems to be established again along the coasts of Brittany. This tends to confirm the shift of the distribution of the species in certain European waters. Long term monitoring, diet and genetic studies are now planned for a better understanding of this shift, and for the effective implementation of a conservation plan.

scholarly journals Aerial line transect survey to estimate abundance of marsh deer (Blastocerus dichotomus) (Illiger, 1815)

2005 ◽  
Vol 48 (5) ◽  
pp. 807-814 ◽  
Author(s):  
Artur Andriolo ◽  
Ubiratan Piovezan ◽  
Mateus José Rodrigues Paranhos da Costa ◽  
Jeff Laake ◽  
José Maurício Barbanti Duarte
Keyword(s):  
Population Size ◽  
River Basin ◽  
Distance Sampling ◽  
Aerial Survey ◽  
Line Transect ◽  
Sampling Methodology ◽  
Future Analysis ◽  
Line Transect Survey ◽  
Blastocerus Dichotomus ◽  
The Impact

The objective was to estimate abundance of marsh deer in the Paraná River basin of this work. The results provided information to support further analysis of the impact of the Porto Primavera flooding lake over population. Sixty-nine animals were recorded by aerial survey using distance sampling methodology. Animals were widely distributed throughout the study area. The uncorrected data resulted in a estimate density of 0.0035 ind/ha and a population size of 636 individuals. Correcting the g for the animals that could be missed the calculated abundance was 896 (CV=0.27) individuals. This methodology was applied with success to survey marsh deer. The result was important to evaluate the marsh deer status in the area, and for future analysis of the impact of the flooding dam.

scholarly journals Group IV humpback whales: their status from aerial and landbased surveys off Western Australia, 2005

2020 ◽  
pp. 223-234
Author(s):  
Charles G.M. Paxton ◽  
Sharon l. Hedley ◽  
John l. Bannister
Keyword(s):  
Aerial Survey ◽  
Group Iv ◽  
Humpback Whales ◽  
Reliable Estimate ◽  
Line Transect ◽  
Absolute Abundance ◽  
Density Estimates ◽  
Abundance Estimates ◽  
Short Period ◽  
Land Station

Single platform aerial line transect and land-based surveys of Southern Hemisphere Group IV humpback whales were undertaken to provide absoluteabundance estimates of animals migrating northward along the western Australian coast during June–August 2005. The aerial survey was designedto cover the whole period of northward migration but the resulting estimates from that survey alone could only, at best, provide relative abundanceestimates as it was not possible to estimate g(0), the detection probability along the trackline, from the data. Owing to logistical constraints, theland-based survey was only possible for a much shorter period (two weeks during the expected peak of the migration in mid-July). This paperproposes three methods that utilise these complementary data in different ways to attempt to obtain absolute abundance estimates. The aerial linetransect data were used to estimate relative whale density (for each day), allowing absolute abundance from the land-based survey to be estimatedfor the short period of its duration. In turn, the land-based survey allowed estimation of g(0) for the aerial survey. Absolute estimates of abundancefor the aerial survey were obtained by combining the g(0) estimate with the relative density estimates, summing over the appropriate number ofdays. The most reliable estimate of northward migrating whales passing the land station for the period of the land-based survey only was 4,700(95% CI 2,700–14,000). The most reliable estimate for the number of whales passing through the aerial survey region for the duration of that survey(55 days from June through to August) was 10,300 (95% CI 6,700–24,500). This is a conservative estimate because the duration of the aerial surveywas almost certainly shorter than the period of the migration. Extrapolation beyond the end of this survey was considered unreliable, but abundancefrom the estimated start of the migration to the end of the survey (87 days from mid-April to August) was estimated to be 12,800 (95% CI 7,500–44,600). The estimated number of whales depends crucially on the assumed migration and period of migration. Results for different migrationparameters are also presented. The point estimates of abundance, whilst higher than those from a previous survey in 1999 (when adjusted for surveyduration) are not significantly so. The peak of the whales’ distribution was found at c.90m water depth.

scholarly journals Opportunistically collected data from aerial surveys reveal spatio-temporal distribution patterns of marine debris in German waters

2020 ◽  
Vol 28 (3) ◽  
pp. 2893-2903
Author(s):  
Bianca Unger ◽  
Helena Herr ◽  
Sacha Viquerat ◽  
Anita Gilles ◽  
Patricia Burkhardt-Holm ◽  
...  
Keyword(s):  
Temporal Distribution ◽  
Distribution Patterns ◽  
Aerial Survey ◽  
Marine Debris ◽  
Encounter Rate ◽  
The North ◽  
Aerial Surveys ◽  
Spatio Temporal ◽  
German Waters ◽  
The Baltic

AbstractMarine debris is known for its ubiquitousness and harmful effects on marine life. This study is the first analysis to provide information on the distribution of floating marine debris in German waters using aerial survey data collected between 2002 and 2016. During regular harbour porpoise monitoring flights, 191,167 km were covered and 26,512 floating debris items recorded (average encounter rate 0.1387 items/km). Debris was encountered more often in the North Sea than in the Baltic Sea (0.16 items/km; 0.08 items/km). The average encounter rate was higher in offshore waters than in coastal areas. Overlaps of marine debris distribution with ‘Special Areas of Conservation’ are a particular reason for concern. Moreover, the spring months (March–May) were identified to be the time of the year with the highest average encounter rates for marine debris. Fishing-related debris was shown to contribute up to 25% of the total number of all observed items. This study shows that opportunistically collected data on marine debris from aerial surveys are valuable for identifying distribution patterns of floating debris without additional survey effort and costs. These data can be used as baseline information to inform management schemes such as the Marine Strategy Framework Directive.

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