An Evaluation of the Strip Transect Method for Censusing Bird Communities in Forests

1986 ◽  
Vol 13 (2) ◽  
pp. 203 ◽  
Author(s):  
RH Harden ◽  
RJ Muir ◽  
DR Milledge
Keyword(s):  
New South ◽  
Bird Communities ◽  
Density Estimate ◽  
Density Estimates ◽  
Number Of Species ◽  
South Wales ◽  
Sclerophyll Forest ◽  
Transect Counts ◽  
Estimate Number ◽  
Strip Transect

The effects of varying transect width and census duration on the number of birds counted, the density estimate, number of species detected and the percentage of unidentified birds were examined in rainforest and wet sclerophyll forest at Mount Nardi in northern New South Wales. The nine combinations of three strip widths (40, 60 and 80 m) and three durations of census (24, 18 and 12 min) were compared in 200-m-long transects in each forest. The census of birds was more sensitive to changes in census duration than in strip width, and the effects were greater in the rainforest than the wet sclerophyll forest. Both the precision of the density estimates and the number of species detected were highest for the narrowest strips censused for the longest time. The bias of the density estimate varied with the treatments both within and between forests, and thus the strip transect could not be used to compare them. We suggest that variation in bias between sites may be a problem common to all transect counts of birds.

Comparison of Bird Counts From Pine Forest and Indigenous Vegetation.

1977 ◽  
Vol 4 (3) ◽  
pp. 281 ◽  
Author(s):  
PV Driscoll
Keyword(s):  
Pinus Radiata ◽  
New South ◽  
New South Wales ◽  
Bird Communities ◽  
Pine Forest ◽  
Native Forest ◽  
Number Of Species ◽  
Eucalyptus Forest ◽  
South Wales ◽  
Forest Habitats

Bird counts were taken in Feb., March and July 1975 in 4 native habitats, ranging from wet sclerophyll Eucalyptus forest to mallee (E. stricta)-heath on the Boyd Plateau, and two Pinus radiata habitats (20 yr and 40 yr) in the Jenolan State Forest, New South Wales, Australia. In each season the number of birds and the number of species was highest in the native forest habitats, lower in the pine habitats and least in the mallee-heath. The composition of native forest, pine forest, and mallee-heath bird communities shows considerable differences.

Pattern analysis of Scleropyll trees aggregated to different degrees

1970 ◽  
Vol 18 (2) ◽  
pp. 237
Author(s):  
WE Westman ◽  
DJ Anderson
Keyword(s):  
Mathematical Models ◽  
Tree Species ◽  
Pattern Analysis ◽  
New South ◽  
Analysis Data ◽  
Eucalypt Forest ◽  
South Wales ◽  
Sclerophyll Forest ◽  
The One ◽  
Block Sizes

Pattern analysis data are presented for a number of tree species populations sampled from two sites located in dry sclerophyll forest within the Ku-ring-gai Chase park of New South Wales. The distributions proved to be predominantly contagious or random, with regularity occurring only occasionally. Observed variations in the degree of aggregation exhibited by a species were taken into account in interpreting pattern analysis curves. The relation of pattern analysis data to sample quadrat data fitted to known mathematical models is extremely variable, and it is shown that pattern at block sizes other than the one under consideration may suppress the appearance of deviations from randomness at block sizes which do show contagion when sampled with randomly placed quadrats. The possible origins of contagious distributions in eucalypt forest are briefly discussed.

Bird communities in remnant woodland on the New England Tablelands, New South Wales

2006 ◽  
Vol 12 (1) ◽  
pp. 50 ◽  
Author(s):  
S. J. S. Debus ◽  
H. A. Ford ◽  
D. Page
Keyword(s):  
New England ◽  
New South ◽  
Full Range ◽  
New South Wales ◽  
Bird Species ◽  
Bird Communities ◽  
Active Management ◽  
Private Land ◽  
Bird Species Richness ◽  
South Wales

We provide a geographic and landscape context for ongoing studies on bird communities in eucalypt woodland remnants on the New England Tablelands, New South Wales. We draw together several surveys that have not been published in the scientific literature, and integrate them with previously published material. A total of 142 woodland bird species, including 12 threatened species, was recorded in remnant woodland in the area above 900 m elevation from 50 km SSE to 100 km NNW of Armidals. There was a positive relationship between remnant size and bird species richness. Woodland reserves >300 ha supported significantly more species than remnants <100 ha on private land. Intensively surveyed reserves also had more species than remnants surveyed more casually. Threatened and other declining species occurred mainly in medium-sized (100-300 ha) and large reserves; foraging guilds of small to medium-sized, ground and above-ground insectivores were impoverished in degraded medium-sized and small remnants on private land. Almost the full range of woodland bird species was found at one or more sites, indicating their conservation value. However, some species were found in few sites or were only vagrants at a site. Active management will be needed to retain the current diversity of bird species in such heavily cleared landscapes.

scholarly journals Activity patterns and roosting of the eastern blossom-bat (Syconycteris australis)

2014 ◽  
Vol 36 (1) ◽  
pp. 29 ◽  
Author(s):  
Rebecca L. Drury ◽  
Fritz Geiser
Keyword(s):  
New South ◽  
Radio Telemetry ◽  
Activity Patterns ◽  
Behavioural Thermoregulation ◽  
Roost Selection ◽  
South Wales ◽  
Sclerophyll Forest ◽  
Open Ground ◽  
Foraging Site ◽  
Cabbage Palm

We quantified activity patterns, foraging times and roost selection in the eastern blossom-bat (Syconycteris australis) (body mass 17.6 g) in coastal northern New South Wales in winter using radio-telemetry. Bats roosted either in rainforest near their foraging site of flowering coast banksia (Banksia integrifolia) and commuted only 0.3 ± 0.1 km (n = 8), whereas others roosted 2.0 ± 0.2 km (n = 4) away in wet sclerophyll forest. Most bats roosted in rainforest foliage, but in the wet sclerophyll forest cabbage palm leaves (Livistonia australis) were preferred roosts, which likely reflects behavioural thermoregulation by bats. Foraging commenced 44 ± 22 min after sunset in rainforest-roosting bats, whereas bats that roosted further away and likely flew over canopies/open ground to reach their foraging site left later, especially a female roosting with her likely young (~4 h after sunset). Bats returned to their roosts 64 ± 12 min before sunrise. Our study shows that S. australis is capable of commuting considerable distances between appropriate roost and foraging sites when nectar is abundant. Bats appear to vary foraging times appropriately to minimise exposure to predators and to undertake parental care.

The impact of trampling on feldmark vegetation in Kosciuszko National Park, New South Wales

2004 ◽  
Vol 52 (3) ◽  
pp. 315 ◽  
Author(s):  
K. L. McDougall ◽  
G. T. Wright
Keyword(s):  
National Park ◽  
New South ◽  
New South Wales ◽  
Species Abundance ◽  
Management Options ◽  
Cushion Plants ◽  
Number Of Species ◽  
South Wales ◽  
Westerly Winds ◽  
The Impact

A popular walking track in Kosciuszko National Park, New South Wales, passes through areas of feldmark vegetation, a windswept community of sparse dwarf shrubs, cushion plants and herbs. The prevailing westerly winds in this area prune the windward edges of the dominant Epacris gunnii shrubs. Layering on the protected side effectively means that the shrubs slowly move across the ridgetops. Twenty-five transects were placed perpendicular to the track in a patch of feldmark north of Mt Kosciuszko. The density of selected species and the total number of species were recorded in quadrats placed in the track centre, track edges and feldmark vegetation at 5 and 10 m from both sides of the track to determine whether the track has interrupted feldmark processes and affected species abundance. The abundance of all species and the number of species per quadrat was lowest in the track centre. Three species (including E. gunnii) were found to be less abundant on the leeward edge of the track than on the windward edge, suggesting that the track has indirectly interfered with feldmark processes. Two of the species were as abundant on track edges as at 5 and 10 m from the track. The area of affected vegetation is currently very small and it may take decades before the effect is obvious to people using the track. Management options for reducing or eliminating the impact are discussed.

Conventional distance sampling versus strip transects and abundance indices for estimating abundance of greater gliders (Petauroides volans) and eastern ringtail possums (Pseudocheirus peregrinus)

2019 ◽  
Vol 46 (6) ◽  
pp. 518
Author(s):  
Luke D. Emerson ◽  
Guy-Anthony Ballard ◽  
Karl Vernes
Keyword(s):  
Distance Sampling ◽  
Probability Of Detection ◽  
Density Estimate ◽  
Imperfect Detection ◽  
Density Estimates ◽  
Transect Line ◽  
Eucalypt Forest ◽  
Arboreal Marsupials ◽  
Abundance Indices ◽  
Strip Transect

Abstract ContextAccurate estimates of abundance are extremely useful for wildlife management and conservation. Estimates generated from distance sampling are typically considered superior to strip transects and abundance indices, as the latter do not account for probability of detection, thereby risking significant error. AimTo compare density estimates generated from conventional distance sampling (CDS) of arboreal marsupials with strip transect density estimates and abundance indices. MethodsOff-track CDS and strip transects were used to estimate densities of P. volans and P. peregrinus across ~2.6km2 of remnant eucalypt forest at Mt Duval in north-eastern New South Wales. Key resultsCDS density estimates for P. volans (1.36ha−1, 95% confidence interval (CI) of 1.07–1.72ha−1) and P. peregrinus (0.28ha−1, 95% CI 0.22–0.35ha−1) were consistent with densities reported in other studies conducted in open eucalypt forests. A strip transect width of 40m for P. volans resulted in a collective set of values for density (1.35ha−1), error (s.e.±0.14), precision (cv 0.10) and 95% CI (1.07–1.62ha−1) closest to those associated with the CDS-generated density estimate (1.36ha−1, s.e.±0.15, cv 0.10, 95% CI 1.07–1.72ha−1). Strip widths of 10 to 40m resulted in density estimates for P. peregrinus closest to those generated through CDS, but much less precise. ConclusionsAlthough a 40-m wide strip transect provided a robust density estimate for P. volans at Mt Duval, this is unlikely to be consistent across different study areas. Strip transects provided less precise density estimates, or underestimated P. peregrinus density at Mt Duval, when compared with CDS density estimates. CDS should be favoured over strip transects or abundance indices for estimating P. volans and P. peregrinus abundance, because it is capable of providing more meaningful and robust abundance estimates by accounting for the probability of detection from the transect line across different habitats. ImplicationsResearchers, conservation managers and decision makers should be aware that common methods for assessing arboreal marsupial abundance have serious potential weaknesses. Thus, it would be prudent to invest in studies that address imperfect detection to improve the quality of monitoring data.

Distribution and Aspects of the Biology of the Parma Wallaby, Macropus parma, in New South Wales

1977 ◽  
Vol 4 (2) ◽  
pp. 109 ◽  
Author(s):  
GM Maynes
Keyword(s):  
New South ◽  
New South Wales ◽  
Embryonic Diapause ◽  
Body Measurements ◽  
Adult Males ◽  
Limited Data ◽  
Adult Females ◽  
South Wales ◽  
Sclerophyll Forest ◽  
The Mean

M. pauma, which was formerly thought to be extinct in Australia, has been found in the Great Dividing Range of coastal New South Wales between 29D 28' and 32D 23's. The optimum habitat appears to be areas of wet sclerophyll forest with a thick shrubby understorey in association with grassy areas. Although the species may be locally common, its present status is best defined as rare; it has a limited distribution and normally occurs at a low density throughout its range. Limited data indicate that most young are born between February and June. Two of six females examined were probably in embryonic diapause. Females may mature sexually as early as 12 months old, and at a weight of 2.6-2.8 kg. Adult females in Australia were significantly heavier than those in New Zealand (Kawau I.), and larger in seven external body measurements. In contrast, adult males were significantly larger in Australia than Kawau I. in ear length only. The species is mainly nocturnal and the mean group size is 1.34 animals, i.e. it is usually single individuals that are encountered.

scholarly journals An assessment of the accuracy of kangaroo surveys using fixed-wing aircraft

1998 ◽  
Vol 25 (3) ◽  
pp. 315 ◽  
Author(s):  
A. R. Pople ◽  
S. C. Cairns ◽  
T. F. Clancy ◽  
G. C. Grigg ◽  
L. A. Beard ◽  
...  
Keyword(s):  
Standard Form ◽  
Cost Effective ◽  
Line Transect ◽  
Attractive Alternative ◽  
Correction Factors ◽  
Density Estimates ◽  
Macropus Rufus ◽  
Transect Counts ◽  
Biased Estimates ◽  
Strip Transect

The use of line-transect methodology, on foot or from a helicopter, is likely to return the most repeatable, least biased estimates of kangaroo density. However, the associated costs make both methods impractical for broad-scale surveys. For these, a fixed-wing aircraft remains the most cost-effective platform. Limitations of the standard fixed-wing method (200-m strip transects) are well known, but it continues to be used because it provides an index of trends, because there are now long runs of data (almost 20 years in some cases) collected in this standard form and an alternative method is lacking. In this study, four variations of fixed-wing surveys of kangaroos were investigated: two line-transect methods (involving different scanning techniques), the standard 200-m strip transect and a 100-m strip transect. Surveys using these methods were compared with helicopter line-transect surveys along the same flight lines in three areas (5000–7500 km2) in western Queensland. Both fixed-wing line-transect methods failed to produce consistently accurate estimates of density for all three species surveyed: red kangaroos (Macropus rufus), eastern grey kangaroos (M. giganteus) and common wallaroos (M. robustus). While generally more accurate than the uncorrected strip-transect counts, they were no less variable. However, the strip-transect counts still need to be corrected for bias for which this study offers revised estimates of correction factors for eastern grey kangaroos (3.7–10.2) and common wallaroos (3.8–4.1), and estimates for red kangaroos (1.7–2.7) that support currently used values. An attractive alternative is to survey in 100-m strip transects, which offer improved visibility (correction factors of 1.0–1.8 for red kangaroos, 2.1–3.6 for eastern grey kangaroos and 1.7–2.1 for common wallaroos) and are therefore likely to be more accurate and repeatable. However, these advantages need to be assessed in relation to continuing long runs of data using the standard 200-m strip transect. Correction factors for wallaroos are conservative as helicopter-based density estimates are known to be underestimates. Further work is needed to assess the generality of correction factors, both spatially and temporally.

scholarly journals Comparison of Surveys of Kangaroos in Queensland Using Helicopters and Fixed-Wing Aircraft.

1998 ◽  
Vol 20 (1) ◽  
pp. 92 ◽  
Author(s):  
AR Pople ◽  
SC Cairns ◽  
TF Clancy ◽  
GC Grigg ◽  
LA Beard ◽  
...  
Keyword(s):  
Aerial Survey ◽  
Population Estimates ◽  
Line Transect ◽  
Correction Factors ◽  
Density Estimates ◽  
Australian State ◽  
Transect Counts ◽  
Comparative Accuracy ◽  
Harvest Quotas ◽  
Strip Transect

Kangaroo harvest quotas for each Australian state have been set mainly as proportions of population estimates derived from aerial surveys. Estimating population size from strip transect counts using fixed- wing aircraft has become an established technique, but counts must be adjusted by correction factors to ensure population estimates are both accurate and repeatable. Surveys of kangaroos in Queensland are currently conducted with helicopters using line transect methodology, but cost restricts their use to relatively small survey blocks. Nevertheless, they return more accurate and repeatable estimates of kangaroo density than surveys with fixed-wing aircraft. A comparison of the above two techniques was made along the same transect lines in seven survey blocks (5000-10,000 km2) in southern and western Queensland, allowing an assessment of the comparative accuracy of the fixed-wing method. For red kangaroos (Macropus rufus), required correction factors of 0.7-3.1 were similar to those used previously. However, for eastern grey kangaroos (M. giganteus), substantially larger correction factors of 3.4-10.2 were needed to approach true density. For wallaroos (M. robustus), correction factors of 3.8-4.8 were required, but can be considered conservative because helicopter-derived density estimates are known to be underestimated by a factor of 2-3. Further work is needed to establish how correction factors for each species should be applied on a broader scale and whether they lead to repeatable estimates of kangaroo density. Key words: aerial survey, line transect, correction factors, strip transect, wallaroo.

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