Research Repository :: Browsing by Author "Senzota, Ramadhani. B.M"

Browsing by Author "Senzota, Ramadhani. B.M"

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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.
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).
Environmental Status at Samunge Village (Tanzania) Following a Sharp Increase in Visitors
(2012) Senzota, Ramadhani. B.M
Starting early 2011, people from all over Tanzania, Africa and overseas flocked Samunge Village in northern Tanzania, to drink a cup of Carissa spinarum concoction claimed to treat diseases hitherto known to be incurable by conventional medicine including HIV-AIDS, hypertension and diabetes. The big number of visitors resulted into vivid environmental impacts including trampling on plants and animals, unplanned discarding of drink and food containers, haphazard sanitation undertakings and overall change in panorama. The present study made some quantification on environmental status in the village during the peak visitor days in March 2011. There was widespread trampling and denudation of vegetation up to 200 m around the road leading to the village centre where the medicine was being administered. Small animals were trampled by vehicles and humans. Litter from mineral water and food containers was significantly more concentrated nearer the road than further away, but was spread to over 200 m from the road as was human refuse resulting from sanitary undertakings. The hitherto panorama of alternating green hills and lowlands became bisected by a long chain of different types of vehicles including large and small lorries, large and small buses, Land Cruisers, Land Rovers and saloon cars. There was widespread tree and shrub harvesting for firewood, temporary shelter and medicine. To reduce level of environmental impact the road needed improvement to ease vehicle movements, the number of vehicles and people going to the village for the medicine needed to be regulated and sanitary facilities installed along the road.
Further Evidence of Exogenous Processes Regulating the Population of Zebra in the Serengeti
(1988-03) Senzota, Ramadhani. B.M
Between 1970 and 1980 the population size of the migratory zebra in the Serengeti remained constant. During the same period the population of wildebeest, also a large migratory ungulate, increased in a manner compatible with existing ecological theories. Sinclair & Norton-Griffiths (1982) have produced evidence to suggest that predation pressure was the factor that prevented the zebra population from increasing. This paper presents further evidence, based on population structure, which shows that the size of zebra population should have increased.
Impact of Small Scale Gold Mining on Soils of the Wetland Forests in East Usambara, Tanzania
(2007) Kweyunga, C.; Senzota, Ramadhani. B.M
Soil pits in disturbed and natural wetland forests of East Usambara were excavated and soil profile samples collected and analysed for physical and chemical properties. Their physical and chemical characteristics were found to be sharply different from those of the surrounding hills. Differences included lack of A Horizon, water saturation, presence of very high organic matter, very low pH and hence very poor in basic cations, and low microbial activity. Nutrient recycling, especially nitrogen and phosphorus, tended to shift from mineralization to immobilization. Effects of soil disturbance on both physical and chemical characteristics of the soils were also very vivid. The soils disturbed from gold mining possessed an altered soil structure, improper development of soil horizons and removal of organic matter on the surface. Burried A horizons were found in all plots at the disturbed site. Carbon:Nitrogen ratios were significantly higher in the undisturbed forests suggesting greater capacity in carbon sequestration. Both sites existed in the same general area but while the undisturbed one possessed all histosol (organic soil) characteristics, the disturbed site soils were heterogenous and possessed characteristics associated with mineral soils (inceptisols). The present study suggests that disturbance has led into a reduction in the supply capacity of minerals such as nitrogen and phosphorus, and the low supply of such minerals will inhibit regrowth of the natural vegetation.
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.
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
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
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.
Plains Gerbils (Gerbilliscus robusta) as Food of the Barn Owl (Tyto alba) in the Serengeti Plains (Tanzania): Thirty-Six Years Later
(2012) Senzota, Ramadhani. B.M
The barn owl (Tyto alba (Blyth 1862) roosts and nests in crevices and caves of kopjes (rock outcrops) of the Serengeti plains. Its major food in the 1970’s was found to be Gerbilliscus robusta (Cretschmer 1826) which inhabits the expansive grasslands surrounding the kopjes. In October 2012, pellets of the owl were collected from one of its roosting cave in the Gol Kopjes at the plains; the roosting cave was the same as one where a 1976 pellet collection was made. Collected intact and disintegrated pellets were weighed and sorted to identify and enumerate their contents. Morphometrics of sorted out bony remains from the pellets were measured to assist in identifying the taxonomic status of the pellet contents and in determining the size ranges (including lengths and widths) of bone pieces ingested by the owls. Pellet contents of the 2012 collection were found to be of similar sizes and types as those of 1976 suggesting that species composition of the pellet contents was similar over the 36 year period. Skull and other bone contents were mostly (about 90%) of Gerbilliscus robusta, suggesting this rodent to still be an important food item of the barn owl in the Serengeti short grassland plains.
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.
Power to Detect trends in Ecological Indicators in the East Usambara Mountains, Tanzania
(2003-12) Newmark, William D.; Senzota, Ramadhani. B.M
We evaluated the statistical power of monitoring protocols to detect, over a 10-year period, trends in indices of abundance of primates, hornbills and forest interior dung beetles and growth rates of epiphytic ferns in the Amani Nature Reserve, in the East Usambara Mountains, Tanzania. Local technicians are responsible for the day-to-day gathering of data. The existing monitoring protocols for blue monkey, silver-cheeked hornbills, trumpeter hornbills, forest interior dung beetles and Asplenium nidus have sufficient statistical power (>0.80) to detect trends of 65% or less over a 10-year period. Monitoring protocols for black and white colobus and Asplenium holstii have lower statistical power (<0.80). We therefore conclude that the majority of monitoring protocols of the East Usambara Ecological Monitoring Project have the capacity both logistically and statistically to detect long-term trends in important functional groups in the East Usambara Mountains.
Wildlife Mortality on Foot Paths of the University of Dar es Salaam,
(2012) Senzota, Ramadhani. B.M
Human population on the University of Dar es Salaam, Mlimani Campus, has increased substantially in recent years. It is expected that the number of small animals trampled and killed by pedestrians is correspondingly increasing but no baseline study has hitherto been conducted. Between May 2007 and August 2008, over 1,000 animals trampled by humans walking along foot paths at the main Campus of the University of Dar es Salaam, Tanzania, were identified and enumerated. Human presence along foot paths was also recorded as well as animals killed by vehicles on roads of the campus and surrounding areas. Variations between foot paths, months, seasons and level of human abundance were examined. Invertebrates were the most common animal kills on foot paths while most vertebrate kills were along roads. Foot path deaths peaked during semester periods when pedestrian numbers increased. Types and numbers of animals killed differed between foot paths, apparently in relation to adjacent habitat. Tunnels placed at various sections of the paths would facilitate small animals crossings and reduce mortality. Despite having the highest concentration of pedestrians, a bridge path (path C) scored one of the lowest death tolls

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