Community ecology of rodents in a natural and agricultural landscape- in Western Serengeti, Tanzania
| dc.contributor.author | Rwebuga, Egidius James | |
| dc.date.accessioned | 2026-01-17T17:30:06Z | |
| dc.date.available | 2026-01-17T17:30:06Z | |
| dc.date.issued | 2024 | |
| dc.description | Dissertation | |
| dc.description.abstract | Rodents are beneficial ecologically as they act as food for other organisims including humans. However, about 17% of rodent species are problematic since they transmit zoonotic diseases, damage properties and depredate crops. Various strategies have been designed worldwide to control them but have proven futile due to limited knowledge on the animals’ biology, behaviour and ecology. This knowledge is essential for preparing integrated rodent conservation and management strategies. Also, no one single strategy can effectively be used to manage rodents in every part of the world, hence rodent ecological studies in as many local areas as possible are needed. Therefore, two ecological studies were carried out to generate information that would contribute to the formulation of effective strategies. The first study aimed to determine: i) spatio-temporal community structure (species composition, age and sex structure), ii) spatio-temporal population dynamics and breeding patterns and iii) influence of ecological factors (vegetation attributes, soil characteristics and seasonality) on abundance of a dominant rodent species M.natalensis. The second study aimed at investigating the dietary patterns of the dominant rodent species. These are the first detailed ecological studies in our study area. The first study was conducted within Kijereshi Game Reserve and the surrounding Nyamikoma village in the western Serengeti using Capture- Mark-Recapture (CMR) technique from April 2020 to March 2022. Sherman live traps were used to trap rodents on a 3 consecutive night’s basis every month for twenty four months. Trapping was done in nine 70 x 70 m2 permanent grids in the wooded grassland habitat within Kijereshi Game Reserve, and in fallow land and maize crop fields within Nyamikoma village land. One year data collected from from 2020 April to March 2021 were used to investigate spatio-temporal community structure of rodents in the three habitats whereby 1,075 individuals were captured. They comprised eight 8 rodent species and one shrew species. Mastomys natalensis (76.6%) was the most whereas Acomys wilsoni (02%) occurred the least abundant species across habitats and the insectivorous animal was Crocidura cf. flavescens (11.1%). Species richness was highest in the wooded grassland and least in maize crop fields, probably due to mono-cultivation nature in the maize crop fields. Fallow land had a higher diversity (1.05) while maize fields had the lowest (0.35), suggesting presence of heterogeneity in fallow land habitats as compared to maize crop fields. A statistical difference in number of adults, subadults and juveniles was detected between habitats (F2, 102 = 3.09, P=0.05), and a marginally significant difference between seasons (F1, 102 = 3.743, p = 0.06). There were more Juveniles in the maize crop fields than in the wooded grassland habitat probably due to availability of food resources that favour their reproduction. On the other hand, there was a significant difference between numbers of females and males of M. natalensis captured across dry and wet seasons (F1, 64 = 8.311, p = 0.005) and the three habitats (F2, 64 = 6.9, p = 0.004). The study suggests that small scale comparisons of the community structures of small mammals between habitats can provide knowledge that is needed for conservation and control of small mammal species. A two year period data on population dynamics and breeding patterns of M.natalensis revealed that, its abundance varied significantly across habitats ( Chi-squared = 8.922, df = 2, p-value = 0.012) and between seasons (W = 982.5, p-value<0.001). Females bred continuously throughout all seasons and there was no significant difference in the number of actively breeding females across habitats (Chi-squared = 3.52, df = 2, p-value = 0.172) and between seasons (W = 584, p-value = 0.472) probably due to presence of seeds/grains especially in maize crop fields throughout the year. However, in most cases breeding started to increase immediately after long rains in March/April except in the wooded grassland where there was a lag. Numerically, the M. natalensis abundance was higher in maize crop fields as compared to other habitats, but densities dropped similarly in all habitats during wet season. Nevertheless, the reasons for this is not yet clear as substantial food resources are available especially in the maize crop fields resulting from maize crops harvest of the second cropping season. Although, analysis of data on several selected ecological correlates, indicated that the latter have influence on the abundance of M.natalensis. For example, its abundance was significantly higher during the dry season and in farmlands than in wet season and protected areas (χ2= 79.393, df = 2, p < 0.001). Also, the abundance significantly associated positively with farmlands (p = 0.023) and sandy- clay-loam soils (p = 0.007). Hence, control of the animals might be effected between the months of November and January when densities are low and farmers should maximize maize production during this period which falls in their minor cropping. Also, soil type issue should be taken into consideration during farm site selection. The second study was conducted in the same study site as the first one, to investigate on the dietary patterns of M.natelensis, whereby, kill traps (Victor kill trap (1.0 x 20.3 x 30.1 cm, Animal Trap Co., Lititz Pennal) baited with peanut butter mixed with maize bran/flour were used in three grids of 70 x 70 m2. About 111 captured specimens were dissected, their stomachs removed and labelled, then preserved in containers (20 ml, glass bottle, HiSupplier_.com) containing 70% ethanol. The analysis of stomach contents was carried out by evenly spreading each stomach contents in a Petridish and categorised using a binocular dissecting microscope under 25 x and 50 x magnification, into various food categories. Overall, vegetative plant materials (41%) andinvertebrates (39.1%) dominated. During the wet season, invertebrates dominated in the wooded grassland, followed by fallow land and maize crop fields. On the other hand, seeds/grains were more eaten in maize crop fields than in other habitat types. Also, in the dry season, vegetative plant materials dominated the animal’s diet in maize crop fields suggesting that this rodent is an opprtunistice feeder. | |
| dc.identifier.uri | https://www.suaire.sua.ac.tz/handle/20.500.14820/7230 | |
| dc.language.iso | en | |
| dc.publisher | Sokoine University of Agriculture | |
| dc.subject | rodent- ecology | |
| dc.subject | Mastomys - natalensis | |
| dc.subject | Kijereshi | |
| dc.subject | Nyamikoma | |
| dc.subject | western -Serengeti | |
| dc.title | Community ecology of rodents in a natural and agricultural landscape- in Western Serengeti, Tanzania | |
| dc.type | Thesis |