Browsing by Author "Nyirenda, Vincent"

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    Does Shore Length Influence Population Size and Density Distribution of Hippopotamus
    (2012-04) Chomba, Chansa; Senzota, Ramadhani. B.M; Chabwela, Harry; Nyirenda, Vincent
    Population surveys of common hippopotamus (Hippopotamus amphibius) in Zambia were carried out between 2005 and 2008 to estimate population size and density distribution patterns against shore length. River bank foot counts were used in the Luangwa River system while boat/canoe counts were used to collect population data from lakes, dams and rivers. Population estimate was 40,060 hippopotami distributed over shore length of 11, 892 km. Luangwa, Zambezi and Kafue Rivers had shore length of 4,150 km which was only 35% of total shore length. The three rivers with only 35% of shore length had 35,000 individuals which was 87.36% of total population estimate, distributed as follows; Luangwa 25,000 (62% of total), Zambezi 6,500 (16% of total) and Kafue 4,000 (10% of total). Chisquare test showed a significant difference in population estimates in Luangwa, Zambezi and Kafue ( 2 , P < 0.05) being highest in the Luangwa (62%), Zambezi (16%) and Kafue (10%) respectively. It was found that shore length did not determine population density distribution. The Luangwa River which was not the longest had the largest number of hippopotamus supporting 62% of the national population estimate. More research is required to investigate other physical and anthropogenic factors determining hippopotamus population density distribution along shore length of water bodies.
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    Dry season herbivore utilization of open grasslands in Lower Zambezi National Park, Zambia
    (2011-11) Chomba, Chansa; Senzota, Ramadhani. B.M; Chabwela, Harry; Mwitwa, Jacob; Nyirenda, Vincent
    Utilisation of open grassland plains by large herbivores (≥100 kg) and harvester ants (Messor capensis) in Lower Zambezi National Park, Zambia was assessed every September from 1997 to 2007. A point intercept method was used to estimate percent cover for grass, shrub, bare, litter, herbivore droppings and presence of harvester ants in the Jeki open grassland vegetation community as indicators of range condition. Results showed a reduction in grass cover from 35% in 1997 to 10% in 2007 while litter remained stable. Incidence of herbivore droppings and harvester ants showed a decline while shrub cover and species composition of shrubs increased significantly. As grass cover and grass species composition declined, herbivore droppings and incidence of harvester ants also decreased. Unpalatable species such as Vernonia spp. were assumed to be signs of poor quality range. Increase in bush encroachment indicated heavy utilization by herbivores in the dry season when quality of range deteriorated as a consequence of over utilization of grass species. Further research is required to determine population estimates and grazing capacity of key herbivores such as buffalo (Syncerus caffer).
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    The Influence of Grass Biomass Production on Hippopotamus Population Density Distribution along the Luangwa River in Zambia
    (2011-04) Chansa, Wilbroad; Senzota, Ramadhani. B.M; Chabwela, Harry; Nyirenda, Vincent
    Hippopotamus is a selective nocturnal grazer consuming 50 kg of grass. Due to its large body size, it requires large areas of grass often exceeding 5 hectares within 2-5 km of the water body to maintain good body condition. In this study, hippo population size and density, grass biomass and grazing capacity were assessed in March 2008 along a 165 km stretch of the Luangwa River. The study area was subdivided into study blocks, A, B, C, D, E and F. Methods used were: river bank total counts, quadrat sampling and identification of all grass species, clipping of grass in a quadrat, drying of clipped grass at constant temperature of 70oC and weighing to obtain dry weight. Grazing capacity of the hippo was estimated based on grass biomass values obtained during the study. Hippo population density was then matched with grass biomass distribution along the study blocks A-H. Total primary production was 62, 800 kg with mean biomass per study block of 7, 850 kg /ha-1 (in 2008). Grazing capacity was 1 hippo/6 ha-1. Grass biomass varied significantly between river segments being higher in study blocks A, B and E and lower in study blocks C, D, F and G. Mean hippo density was 33 individuals/km stretch of the river. Hippo density was found to be above 33/km in study blocks A, B and E which had higher biomass and lower than 33/km in study blocks C, D, F and G. Hippo population density distribution was found to be influenced by grass species diversity and amount of biomass produced which also determined grazing capacity. In light of global climate change and changing rainfall patterns, more studies are required to determine the influence of rainfall on primary production and how this would affect the increase or decrease in hippo density and grazing capacity in the long-term.
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    The Influence of Host Tree Morphology and Stem Size on Epiphyte Biomass Distribution in Lusenga Plains National Park, Zambia
    (2011-09) Chomba, Chansa; Senzota, Ramadhani. B.M; Chabwela, Harry; Nyirenda, Vincent
    The influence of host tree morphology and stem size on epiphyte biomass distribution in host trees was assessed in Lusenga Plains National Park, Zambia for the period 2004 to 2007. A total of 8 ha were sampled in bush land, woodland and riparian forest vegetation communities. Epiphytes were collected, dried and weighed to obtain biomass, which was apportioned between different host tree species, vertical and horizontal branches, crown and trunk, and small, medium, and large stems, as well as smooth and rough bole textured substrates. Horizontal branches had more epiphytes, 50% than vertical branches (17%). Tree canopies had more epiphyte biomass, 68% than trunks (32%). In riparian forests Usnea articulata and Ramalina reticulata were not selective. In Miombo woodlands, epiphytes and certain tree species with larger stems and rough bore texture were selected. Larger substrates dbh > 100 cm had higher epiphyte biomass (94.46%) followed by medium dbh 51 to 100 cm (5.29%) and the least was on small girth dbh ≥ 20 to 50 cm (0.25%). Rough substrates had 89% biomass and only 11% occurred on smooth bole substrates. It was concluded that tree crowns, horizontal stems and branches, large and rough bole textured tree substrates provided suitable habitat for epiphyte seed settling, germination and moisture retention, while exposure to sunlight supported germination and growth of epiphytes. Maintenance of mature Miombo woodlands was therefore found to be critical in maintaining epiphytes, while protection of preferred tree species would ensure their long-term survival and sustenance of hydrologic functions
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    Lion Hunting and Trophy Quality Records in Zambia for the Period 1967-2000: Will the Trends in Trophy Size Drop as Lion Population Declines?
    (2004-02) Chomba, Chansa; Senzota, Ramadhani. B.M; Chabwela, Harry; Nyirenda, Vincent
    Data on lion skull measurements taken were collected and analyzed to determine trends in trophy size as an indicator of population size, and area of origin among the concessioned hunting areas in Zambia for the period 1967-2000. A comparison of trophy quality was also made with Tanzania and Zimbabwe which were the other two key sources of lion trophies in Africa. It was assumed that a comprehensive analysis of lion trophy sizes obtained from trophy hunting would be used as an indicator of hunting pressure on lion populations in Zambia. This approach was used because trophy size is an index of abundance particularly for species such as lion which are difficult to count using conventional census methods. Record lion trophies from Safari Club International rating were also collected and assessed to compare trophy quality obtained from Zambia and those of Tanzania and Zimbabwe for the same period 1967-2000 (33 years). Results obtained suggested that Zambia’s contribution to the record trophies under Safari Club International did not decline in the intervening period 1967-2000 and could not be used as an effective indicator of lion population in Zambia. At regional level, Zambia had second highest 24%, after Tanzania 56%, while Zimbabwe was third, 20%. It was found that the size of skulls could not be used as an effective indicator of population size as the record trophies did not decline while the population was alleged to have declined on the continent. Other factors, such as genetic, low prey densities, snaring, poisoning and problem animal control needed to be investigated to determine their impact on
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    Patterns of Human – Wildlife Conflicts in Zambia, Causes, Consequences and Management Responses
    (2012-08) Chomba, Chansa; Senzota, Ramadhani. B.M; Chabwela, Harry; Mwitwa, Jacob; Nyirenda, Vincent
    A study was carried out to determine causes, consequences and management responses of human – wildlife conflicts in Zambia during the period 2002 to 2010. Data was collected by field staff in the four management regions of Zambia Wildlife Authority and analyzed to establish patterns and species responsible for human fatalities, livestock predation, crop damage and other damages to human property. During the period of 2002 to 2008, a total of 347 people were killed or 49 people killed annually by five species of wildlife; crocodile, elephant, hippo, lion and buffalo. Nile crocodile killed the largest number of people 185 (53%) and was the most significant cause of human fatalities, the second was hippo 65 (19%) and elephant was third 63 (18%). There were fewer livestock predation incidences and only 305 incidences were recorded which was 12% less than human fatalities. With regard to livestock, the largest number killed was for cattle 159 (52%) and the least was the dog, 8 (2.62%). Lion was responsible for 157 (51%) of all livestock predation incidences and the least was python 1 (0.32%). The most important livestock predators were lion, crocodile and hyaena. Overall, crocodile was responsible for the greatest number of human fatalities and livestock predation combined, 273 (42%) while elephant was responsible for the largest number of crop damage incidences 1,799 (42%). Further research is required to determine gender and age group of people killed, time of the day and activity conducted by the victims at the time of the fatality incidence. Smaller species such as rodents and red billed quelea should also be considered rather than concentrating on large species such as elephant, hippo and buffalo which have meat value.
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    Population Status of theCommon Hippopotamus (Hippopotamus Amphibius) in Luangwa River, Zambia
    (2012-03) Chomba, Chansa; Senzota, Ramadhani. B.M; Chabwela, Harry; Nyirenda, Vincent
    The population size of common hippopotamus, Hippopotamus amphibious in the Luangwa valley, Zambia was assessed for the period of 1976 to 2008. A comparison of historical data on population size for the period of 1952 to1975 was also made. Ecological carrying capacity (K) and carrying capacity band were estimated from data on population size. The river bank foot count method was used, which involved the counting of individuals and taking Global Positioning System (GPS) locations of hippopotamus schools. Ecological Carrying capacity (K) was 6,000 hippopotami and density at K was 35/km. The population was found to be oscillating within carrying capacity band of 2,000 individuals in eight (8) irregular cycles. From K, annual population changes were small and insignificant. A weak correlation was found between population size against time, suggesting a slow down in population growth from 1976 to 2008 (R2 = 0.22). The highest population size of 6,832 hippopotami and density of 42 was reached in 1984. The lowest was 4,765 hippopotami and density of 29/km recorded in 1978. Within the period of 1976 to 2008, the population oscillated between 5,000 and 7,000 individuals, which were symptomatic of a population at K. The slow down in population growth was attributed to environmental resistance. More studies are required to identify factors responsible for environmental resistance which is caused by the rise and fall in the hippopotamus population of the Luangwa River.