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Search Results: 1 - 10 of 262276 matches for " B.K. Reilly "
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Precision of helicopter-based total-area counts of large ungulates in bushveld
B.K. Reilly
Koedoe : African Protected Area Conservation and Science , 2002, DOI: 10.4102/koedoe.v45i2.33
Abstract: Precision in helicopter total-area counts in bushveld for a range of common species are evaluated. Counts were conducted on properties ranging in size from 250 ha to 10 000 ha as part of experiments on precision and power. Counts were conducted in three vegetation types: mopane veld, sourish mixed bushveld and arid bushveld. Scant regard is given to precision as a factor in large herbivore monitoring, with more effort often devoted to accuracy. Coefficients of variation varied from 3.2 % to 70.9 %. Median values are generally acceptable for the establishment of trends for long-term monitoring, but might be inadequate for annual population size monitoring and evaluation. A regression of all species and vegetation types by the standard error showed a significant correlation. Similar regressions were also developed for impala, kudu, warthog, and zebra. Regressions by vegetation type for mopane veld, sourish mixed bushveld, and northwest arid bushveld were also significant. However, the high correlation for some vegetation types might be an artifact of the small sample sizes.
Auditing wildlife
B.K. Reilly,Y. Reillly
Koedoe : African Protected Area Conservation and Science , 2003, DOI: 10.4102/koedoe.v46i2.58
Abstract: Reilly B.K. and Y. Reilly. 2003. Auditing wildlife. Koedoe 46(2): 97–102. Pretoria. ISSN 0075-6458. Accountants and auditors are increasingly confronted with the problem of auditing wildlife populations on game ranches as their clients' asset base expands into this industry. This paper aims to provide guidelines on these actions based on case study data and research in the field of wildlife monitoring. Parties entering into dispute on numbers of animals on a property often resort to their auditors for advice. This paper tracks a method of deciding on whether or not to audit the population based on wildlife value and an initial sample count. This will act as a guideline for the accounting profession when confronted by this problem.
A survey of free-living ixodid ticks on a commercial game farm in the Thabazimbi District, Limpopo Province, South Africa
B. Schroder,A.C. Uys,B.K. Reilly
Journal of the South African Veterinary Association , 2012, DOI: 10.4102/jsava.v77i3.362
Abstract: Free-living stages of ticks on a commercial game farm in the Thabazimbi District, Limpopo Province, South Africa, were collected by drag-sampling with flannel strips during the period September 2003 to August 2004. A total of 5 tick species was collected from 4 sites. Boophilus decoloratus was the most abundant species, followed by Amblyomma hebraeum. Seasonal abundance of the ticks was quantified and an optimum time to implement control measures against the ticks is proposed.
Power and precision of replicated helicopter surveys in mixed bushveld
B.K. Reilly,R.H. Emslie
Koedoe : African Protected Area Conservation and Science , 1998, DOI: 10.4102/koedoe.v41i1.245
Abstract: It is well known that aerial game counts in South Africa are often applied in a non-standardised, unreplicated fashion. They contribute to poor management decisions based on their results as they may be subject to large statistical Type I and II errors. Replicate counts of large herbivores were conducted in a 8 500 ha sample site in the Loskop Dam Nature Reserve in July 1991. These data were used to estimate precision of the counts and estimate statistical power to detect population changes for different combinations of replications and significance levels.
Altertative trophy measuring techniques for African buffalo
S.E. Gandy,B.K. Reilly
Koedoe : African Protected Area Conservation and Science , 2004, DOI: 10.4102/koedoe.v47i1.65
Abstract: The African buffalo is considered the classic African trophy. It is the choice of many hunters who will never go on to hunt any of the other dangerous game animals on the continent. A good trophy is perceived as that of a mature bull with a hardened boss and horn tips that lengthen into sharply pointed hooks. However, indications are that these are the bulls in their breeding prime and there is concern that the continued targeting of these individuals will negatively impact on the population dynamics of the herds, ultimately affecting the sustainability of buffalo hunting. As they age and become postreproductive, the horns broom down, reducing the trophy score under the current measurement systems. A new measuring system is needed that encourages hunters to target the older post-reproductive bulls, instead of those that are still breeding. A random sample of trophies was divided into broomed and non-broomed sub-samples. All key parameters that can be measured in the trophy were measured with a view to identifying the parameters that would allow broomed-down individuals to compete favourably with the non-broomed “classic trophy” in the primary measurement systems, those of Safari Club International and Rowland Ward. An index, created through dividing tip space by the mean of the two individual horn lengths proved to serve the purpose. This factor was then applied to the mean of the SCI and Rowland Ward measurements in the samples. These methods allowed broomed horns to score more points in the record books than non-broomed horns. Boss width and boss space are other possible measurement inclusions that could be considered.
Use of an area-based survey technique to detect vegetation changes in Sour Bushveld
M.D. Panagos,B.K. Reilly
Koedoe : African Protected Area Conservation and Science , 2006, DOI: 10.4102/koedoe.v49i1.105
Abstract: Most strategies for monitoring vegetation change on reserves and game ranches are based on point methods. Area-based methods form the basis of initial floristic classifications from which vegetation maps are constructed. The question arises whether or not these area-based methods can be used for monitoring or not. This paper compares two area-based data sets from the same sites with an intervening period of five years. Data were collected on a Sour Bushveld game farm, in the Limpopo Province of South Africa. The structure of the woody vegetation, particularly in two communities reflected a plant successional progression over time. All six re-surveyed sites reflected an increase in plant species richness and this increase was most substantial in one community where the total number of plant species increased from 17 in 1996 to 34 in 2001 at one sampling site and from 26 in 1996 to 45 in 2001 at the other. This study has shown that change in species composition can be detected using area-based sampling techniques but that absolute measures, such as density, should be employed rather than estimates, especially with regard to plant cover.
Helicopter-based censusing of domestic dogs in Gauteng Province, South Africa
B.K. Reilly,F. Van der Vyver
Journal of the South African Veterinary Association , 2012, DOI: 10.4102/jsava.v71i3.711
Abstract: Decision support in veterinary epidemiology often depends on density estimates of domestic animals. These estimates are usually based on ground surveys of various types. Ground surveys are difficult to undertake in the informal housing settlements that are frequently encountered in developing countries. In addition, they are time-consuming and expensive. In this study, field experience in enumerating wildlife from helicopters was used to count domestic animals in Gauteng Province, South Africa. Data for domestic dogs are analysed for precision and accuracy and the technique evaluated in terms of its value for decision support.
Food preferences of oribi Ourebia ourebi in the Golden Gate Highlands National Park
B.K Reilly,G.K Theron,J du P Bothma
Koedoe : African Protected Area Conservation and Science , 1990, DOI: 10.4102/koedoe.v33i1.452
Abstract: During a two-year study on the ecology of oribi Ourebia ourebi (Zimmermann, 1783) in the Golden Gate Highlands National Park, plant species fed on by oribi were noted. The oribi fed on a total of 22 plant species. Feeding preference categories were assigned according to the degree of use of different plant species, based on direct observation and on a preference rating. The oribi in the Golden Gate Highlands National Park showed a seasonal variation in feeding preferences, utilising several species of forbs primarily during the summer and a marked dif-ference between per cent frequency utilisation of plant species and actual preference rating according to availability of species and for certain plant parts, e.g. for Sporobolus centrifugus.
Natural mortality amoung four common ungulate species on Letaba Ranch, Limpopo Province, South Africa
H.P. Cronje,B.K. Reilly,I.D. Macfadyen
Koedoe : African Protected Area Conservation and Science , 2002, DOI: 10.4102/koedoe.v45i1.12
Abstract: Five years of mortality data of impala Aepyceros melampus, blue wildebeest Connochaetes taurinus, buffalo Syncerus caffer and kudu Tragelaphus strepsiceros have been used to describe the minimum mortality profiles of the respective species in an open savanna system with the full compliment of predators. Predation is the principle cause of natural mortalities on the study site, Letaba Ranch, which is adjacent to the Kruger National Park. The principle cause of impala mortality are leopards Panthera pardus and wild dogs Lycaon pictus. Lion Panthera leo were major contributors to the mortality of wildebeest and buffalo. Anthrax Bacillus anthracis was the main cause of kudu mortality.
Zooplankton diversity of two floodplain lakes (pats) of Manipur, northeast India
Sharma, B.K.
Opuscula Zoologica Instituti Zoosystematici et Oecologici Universitatis Budapestinensis , 2011,
Abstract: Plankton samples collected (November, 2002 – October, 2004) from Waithou and Utra pats, two floodplain lakesin Manipur state of northeast India, revealed species rich zooplankton (121 species) with diverse nature of Rotifera (75 species).The individual pats exhibited rich species diversity (110 and 103 species) and high monthly richness (68±7 and 61±8 species)respectively with higher community similarities. Zooplankton formed important quantitative component (56.0±4.3 % and55.1±5.1 %) of net plankton of the two pats; Rotifera dominantly contributed to their abundance while Cladocera > Copepodawere sub-dominant groups. The richness and abundance showed significant variations between pats and between months andfollowed oscillating annual patterns in each pat except for peaks during winter. Zooplankton indicated higher species diversityand evenness, lower dominance, lack of quantitative importance of individual species, low densities and equitable abundance ofthe majority of species in both pats. The richness correlated inversely only with nitrate in Waithou pat and abundance positivelycorrelated with alkalinity only in Utra Pat. Canonical correspondence analysis (CCA) with abiotic factors explained 55.6 % and61.8% cumulative variance of zooplankton assemblages of Waithou and Utra pats respectively along axis 1 and 2.
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