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An autecological study of bushbuck and common duiker in relation to forest management.Allen-Rowlandson, Timothy Simon. January 1986 (has links)
Frequent reports of damage caused by bushbuck and common
duiker browsing on commercially important timber seedlings,
and an interest in the potential and feasibility of hunting
these two species on State land were the primary factors
responsible for the Directorate of Forestry's motivation of
this study. The study area at Weza State Forest comprised
approximately 21 000 ha of plantations, grasslands and
indigenous forests which were considered representative of
timbered areas throughout the Natal midlands.
Several methods of age determination were investigated
and these findings permitted assessments of growth, fecundity
and population structure. The physiological condition of
both antelope species was examined in relation to age, sex,
reproduction and management strategies, and the results
discussed in conjunction with mortality patterns. Principal
foods of both bushbuck and duiker were determined from rumen
analyses while 112 marked animals were regularly monitored to
facilitate assessments of habitat selection and levels of
spatial and social organisation.
of these largely solitary and
Estimates of the abundance
nocturnal antelope were
influenced by local movements in response to the availability
of food and cover which varied seasonally and also fluctuated
dramatically with forest succession and timber management
activities.
Although bushbuck and duiker bred throughout the year
and had almost identical rates of reproductive performance,
different factors were responsible in limiting the sizes of
these two populations. All the available evidence gathered
in this study indicated that food resources during winter and
early spring were inadequate for bushbuck, particularly in
1983 when 33% of the marked population died from starvation
and/or exposure. Notable differences in forage utilization
and habitat selection inferred little interspecific
competition at this time of the year.
In contrast,
territorial duiker appeared to be susceptible to highly
localised habitat modifications (including the availability of food and cover) which occurred throughout the year and
resulted from silvicultural and timber harvesting practices.
Rumen analyses and quantitative damage assessment
surveys revealed that browsing on timber seedlings was
usually confined to localised areas during the winter months
and was much less severe than had been originally suggested.
Conifers were regarded as a starvati~n food and methods of
reducing damage to these young trees were recommended for
potential problem areas.
Both antelope species were considered overabundant at
Weza and recommendations for the future management of these
populations included the limited utilization of surplus
animals, by sport hunting on a sustained yield basis, and
methods of manipulating and improving forest habitats. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1986.
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Bushbuck ecology and management at Shongweni Dam and Game Reserve.Coates, Gregory David. 29 November 2013 (has links)
Msinsi Holdings (Pty) Ltd are considering the introduction of nyala to Shongweni Dam and Game Reserve in KZN. This reserve has a naturally resident population of bushbuck and is located beyond the natural distribution of nyala. Concerns for competition between these two species causing declines in bushbuck numbers elsewhere prompted the present study. The main aim of the present study was to determine some aspects of the ecology of bushbuck within the reserve to assist with decision-making regarding the introduction of nyala and species specific-management of bushbuck at the study site.
Bushbuck home range and habitat utilisation was investigated with the aid of radio telemetry and Geographical Information Systems. Estimates of total home range
size for males using minimum convex polygons (MCPs) and fixed kernels (FKs) were
33.9 ha and 32.1 ha respectively. Estimates of total home range size for females using
MCPs and FKs were 12.0 ha and 13.5 ha respectively. A significant difference
between total home range size for gender (male and female) was found but there was
no significant difference for age (adult and subadult). Bushbuck typically utilised one
core area within their home ranges in which 50 % of their time was spent in
approximately 17 % and 11.7 % of their total home range for males and females
respectively. A substantial overlap in total home range and core areas between animals was found.
Bushbuck showed preference for short thickets and avoidance of low closed
grasslands. High reedbeds were utilised in proportion to their availability and tallwoodlands were not utilised by the study animals, but were observed to be utilised by other non radio-collared bushbuck. Habitat preference was a consequence of
favourable cover being provided by the structure of the vegetation and the occurrence
of favourable foraging species. Bushbuck utilisation of topographical aspect was
largely determined by the vegetation type that occurred on the respective slopes.
Estimations of bushbuck density and abundance were made using sighting
efforts, drive counts, and mark-resightings. Sighting efforts using distance sampling
during spring were found to be the most effective in terms of accuracy and man-hour
costs, however, these were still not considered to be precise estimations of the total
bushbuck population at SDGR, but would be useful for monitoring population trends
as a result of the high repeatability and simplicity of the method. Sex, age ratios and nocturnal activity were determined using field
classification. The field classification method of age and sex ratio determination used
during the present study was found to be very subjective and was therefore suggested
to have produced ratios which may be largely biased towards the female component
of the population. This in turn also effected the determination of social organization
and was evident when compared to previous studies. Bushbuck activity determined
from radio telemetry and sighting efforts produced results that corresponded with all
previous studies, showing bushbuck to be largely nocturnal, moving much larger
distances at night than during the day, and spending most of their time walking and feeding at night.
The status and management of synoptic bushbuck and nyala in KwaZulu-Natal
was also investigated by means of a questionnaire survey. From the opinions of
landowners and reserve managers, the status of bushbuck sharing a sympatric
relationship with nyala in KwaZulu-Natal (KZN) appeared to be stable to declining,
whereas nyala status was increasing. This trend was suggested to be a result of
competition for resources between the two species. Northern KZN recorded a higher
frequency of this trend (57.7%, n = 26) compared to the Midlands (35.7%, n = 14), as
did Ezemvelo KZN Wildlife Reserves (85.7%, n = 7) compared to privately owned
properties (42.4%, n = 33). Very little species-specific management for nyala and
bushbuck occurred in reserves that participated in the present survey. / Thesis (M.Sc.)-University of KwaZulu- Natal, Pietermaritzburg, 2003.
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Impact of elephant induced vegetation change on the status of the bushbuck (Tragelaphus scriptus ornatus) along the Chobe river in Northern BotswanaAddy, Joanne Estelle 24 June 2015 (has links)
Thesis (M.Sc.)--University of the Witwatersrand, Faculty of Science, 1993.
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Some aspects of the ecology of bushbuck (Tragelaphus scriptus Pallas 1776) in the southern CapeOdendaal, Pieter Benjamin 03 1900 (has links)
Thesis (MSc (Forestry))--Stellenbosch University, 1977. / The social biology and habitat selection of bushbuok, Tragelaphus scriptus, was investigated by ra~io-tracking five bushbuck in the same area, three males and two females. A large degree of over= lap of home ranges was shown to exist. Evidence is advanced to suggest the existence of a time-mechanism to separate individuals whose home ranges overlap. Subadult males have larger home ranges than females. Crepuscular peaks were exhibited in the activity pattern of the study animals. Of 1 380 animals observed in this study, 61% occurred singly and 29% in twos. Breeding is probably throughout the year with peaks in the rate of parturition in April, July-August and November. Bushbuck show a need for canopy cover during the day but will frequent areas with lateral cover or even no cover during the night. Although the indigenous forests are of great importance to bushbuck, evidence was found that they can exist in a very much modified environment such as pinus spp stands. Bushbuck occur at densities of about 3-5 animals!k~ in the Southern Cape. They feed on a wide array of food plants but are mostly browsers with grasses constituting only about five per cent of the diet. A surprisingly high incidence of mushrooms were found in the diet during winter. Some indications exist of the possible presence of sub-optimal feeding conditions during winter. Information is also presented on nutritional element levels, external parasites and morphological data.
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Efficacy of an Electronic Scarecrow on 4 Mammalian Crop-Raiders in Limpopo Province, South AfricaRichardson, Merrie Renee 01 August 2014 (has links)
In South Africa, 2 primate species, Chacma baboons (Papio ursinus) and vervet monkeys (Chlorocebus pygerythrus), and 2 nocturnal mammals, Cape porcupine (Hystrix africaeaustralis) and bushbuck (Tragelaphus scriptus), are among many species of crop raiders. Currently, cost-effective, non-lethal solutions are lacking. From June through December 2012, I installed novel electronic scarecrows on two commercial citrus orchards and a private reserve and used video-recording remote cameras to assess cropraiders’ reactions to them in Limpopo Province, South Africa. I used focal animal sampling data from treatment and control group animals to examine differences in activity budgets and behaviors of interest between groups. Compared to animals at sites with an inactive or no scarecrow, I hypothesized that animals in the treatment group would have altered activity budgets and rates of behaviors; that they would forage or feed less, run more (as a result of being frightened), be more vigilant and thus scan their surroundings more often, and display a visible startle in response to stimuli from scarecrows. Bushbuck at treatment sites spent a larger proportion of their activity budget running, and were more often startled. However, foraging was never observed, and bushbuck in the control group scanned their surroundings more often. Porcupines at treatment sites spent a larger portion of their activity budget running, though foraging was only observed in 1 control group animal and looking was never observed. For primates, treatment (control, scarecrow) was meaningful in explaining differences in focal animal activity budgets of baboons (F = 5.49, P = 0.001) and vervet monkeys (F = 7.09, P = 0.001) as indicated by a permutational MANOVA in R. In baboons, treatment was positively correlated with running; ratios of baboons that ran to baboons that did not run differed between treatment groups (G = 15.78, P < 0.001). Treatment was negatively correlated with feeding; ratios of baboons that fed or foraged to baboons that did not feed or forage differed (G = 5.39, P = 0.02). Significant differences between groups of vervet monkeys were not found with G-tests for the same behaviors of interest. Electronic scarecrows are promising tools for human-wildlife conflict mitigation, particularly for nocturnal antelopes. For primates, further innovation in design of scarecrows to incorporate a visual stimulus is recommended.
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The role of small antelope in ecosystem functioning in the Matobo Hills, ZimbabweLunt, Nicola January 2011 (has links)
The 28-month study assessed the impacts of five syntopic medium-sized mammalian browsers and one fire event in a woodland savanna in the Matobo Hills, Zimbabwe. Aspects of herbivory, mechanical pressures, seed dispersal and nutrient cycling were investigated for three species of small antelope (common duiker [Sylvicapra grimmia]1, klipspringer [Oreotragus oreotragus] and steenbok [Raphicerus campestris]) and two medium-sized species (bushbuck [Tragelaphus scriptus] and greater kudu [T. strepsiceros]). Focusing on Burkea africana2 woodland, in a system that does not include elephant (Loxodonta africana), effects of browsing antelope on woody and herbaceous vegetation development were investigated using exclusion plots. Browsers regulated woody plant cover (measured as basal stem area), with smaller antelope having a greater impact than larger species. This was linked to feeding height, feeding selectivity and mechanical pressures (e.g. twig breakage and trampling). Fire caused an initial reduction in above-ground standing biomass, but in the presence of fauna, pre-fire equilibria were attained within 15 months. In antelope exclosures, herbaceous biomass increased and woody biomass decreased following fire. Responses by woody vegetation to browsing varied among species, with highly palatable species typically exhibiting compensatory regrowth. Woody species richness and abundance (especially of palatable species) increased in the absence of browsers, but species richness of the herbaceous layer was promoted by moderate disturbance (trampling or fire). Faecal deposition behaviour, primarily the use of latrines by small antelope, resulted in localised soil enrichment within defended territories. Decomposition rates (and therefore return of nutrients to the soil) varied among species and seasons, due to defecation site selection, accessibility to decomposers and desiccation rates of faecal pellets. Controlled seed germination experiments indicated that ingestion by small antelope enhances germination rates of large, hard-seeded fruits such as Sclerocarya birrea. However, germination of savanna seeds may require multiple cues. This study demonstrated the critical roles of small antelope in ecosystem functioning, and highlights the importance of the less visible impacts of frequently overlooked smaller mammalian herbivores. Perturbations to the faunal community, especially small antelope, are predicted to have substantial impacts on woody plant cover.
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