Browsing by Author "Massawe, Apia W."

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Application of normalized difference vegetation index (NDVI) to forecast rodent population abundance in smallholder agro-ecosystems in semi-arid areas in Tanzania
(ResearchGate, 2019-05) Hieronimo, Proches; Isabirye, Moses; Kifumba, David; Mulungu, Loth; Kimaro, Didas N; Makundi, Rhodes H.; Leirs, Herwig; Mulungu, Loth S.; Mdangi, Mashaka E.; Massawe, Apia W.
This study aimed to evaluate the potential use of normalized difference vegetation index (NDVI) from satellite- derived remote sensing data for monitoring rodent abundance in semi-arid areas of Tanzania. We hypothesized that NDVI could potentially complement rainfall in predicting rodent abundance spatially and tem- porally. NDVI were determined across habitats with differ- ent vegetation types in Isimani landscape, Iringa Region, in the southern highlands of Tanzania. Normalized differ- ences in reflectance between the red (R) (0.636–0.673 mm) and near-infrared (NIR) (0.851–0.879 mm) channels of the electromagnetic spectrum from the Landsat 8 [Opera- tional Land Imager (OLI)] sensor were obtained. Rodents were trapped in a total of 144 randomly selected grids each measuring 100 × 100 m 2 , for which the corresponding values of NDVI were recorded during the corresponding rodent trapping period. Raster analysis was performed by transformation to establish NDVI in study grids over the entire study area. The relationship between NDVI, rodent distribution and abundance both spatially and tempo- rally during the start, mid and end of the dry and wet sea- sons was established. Linear regression model was used to evaluate the relationships between NDVI and rodent abundance across seasons. The Pearson correlation coefficient (r) at p ≤ 0.05 was carried out to describe thedegree of association between actual and NDVI-predicted rodent abundances. The results demonstrated a strong linear relationship between NDVI and actual rodent abundance within grids (R 2 = 0.71). NDVI-predicted rodent abundance showed a strong positive correlation (r = 0.99) with estimated rodent abundance. These results support the hypothesis that NDVI has the potential for predicting rodent population abundance under smallholder farming agro-ecosystems. Hence, NDVI could be used to forecast rodent abundance within a reasonable short period of time when compared with sparse and not widely available rainfall data.h
Breeding dynamics of rodent species inhabiting farm–fallow mosaic fields in Central Tanzania
(African Zoology, 2012-02) Massawe, Apia W.; Makundi, Rhodes H.; Mulungu, Loth S.; Katakweba, Abdul; Shayo, Teresia N.
The breeding dynamics of three species of rodents, Mastomys natalensis, Aethomys chrysophilus and Gerbilliscus vicina were investigated in a seasonal environment (wet versus dry) in Berega in the eastern parts of central Tanzania. Berega has a distinct unimodal rainfall pattern, with most rainfall from November to April/May. We hypothesized that breeding of rodents in central Tanzania would be confined to the wet season, when unlimited resources would be available for reproduction. We provide evidence of breeding discontinuity in the three species, showing that breeding was seasonally restricted to the wet season and early in the dry season. The observed discontinuity could largely be ascribed to variation in primary productivity between the wet and dry seasons. Reproductively active females were found in the population as early as November, a month into the rainy season, but when early rains occurred, some individuals were already breeding in October. Breeding was more intensive in the latter part of the wet season (March–May) and completely ceased during the dry season. For M. natalensis, survival was highest in the wet period and low in the dry season. The study provides knowledge on the breeding dynamics of rodents in central Tanzania, which can help farmers to take proactive rodent management decisions to prevent high rodent densities and reduce crop damage in the fields. Application of control measures by the community early in the season when populations of reproductive females is lowest will be most rewarding.
Dietary differences of the multimammate mouse, Mastomys natalensis (Smith, 1834), across different habitats and seasons in Tanzania and Swaziland
(CSIRO PUBLISHING, 2011-11) Mulungu, Loth S.; Mahlaba, Themb’alilahlwa A.; Massawe, Apia W.; Kennis, Jan; Crauwels, Dieter; Eiseb, Seth; Monadjem, Ara; Makundi, Rhodes H.; Katakweba, Abdul A. S.; Leirs, Herwig; Belmain, Steven R.
eastern Africa where it can cause significant crop losses. Mastomys natalensis is known to consume a variety of food in response to the availability of food items. However, it is currently unknown whether maize crop growth stages affect the spatio-temporal diet of this species. Aims. We examined the foods consumed by M. natalensis in different habitats and seasons in central Tanzania and Swaziland. Methods. Diet was investigated in Tanzania in four different habitats (woodland, vegetable gardens, maize fields and fallow land) during different maize crop growth stages between March 2008 and February 2009. In Swaziland, this was conducted in three habitats (fallow land, cultivated fields and pristine land) during three crop growth stages (pre-planting, vegetative stage and post-harvest) between March 2008 and April 2009. Micro-histological examination of undigested fragments from the stomachs of trapped animals was made whereby the preserved stomach content was placed in a Petri dish and sorted using a 25 or 50 magnification binocular stereoscope. Stomach contents were identified as: grain and/or seeds (both grasses and maize), plant material (roots, stems and leaves), invertebrates, pods of seeds, fruits (vegetable fruit such as tomato), animal hairs and unidentified matter. If necessary, a lugol solution was used to determine the presence of starch for maize and grass seeds or grains. Key results. In both countries, grain predominated in the diet of M. natalensis. Statistical analyses showed that there were no differences due to seasons or habitats. Therefore, the percentage volume and relative importance were the same across habitats and seasons in both countries. Conclusions. Our findings highlight clearly that M. natalensis is a generalist species feeding on available resources depending on the season and the habitat. Its preference for grain may account for its abundance in maize plantations and confirms it as one of the major pests in crop plantations, especially grain. Implications. This information offers a useful tool for determining the pest status in different habitats and/or seasons. The findings of this study have implications for agriculture and conservation.
Differences in diet between two rodent species, Mastomys natalensis and Gerbilliscus vicinus, in fallow land habitats in central Tanzania
(2011-10) Mulungu, Loth S.; Massawe, Apia W.; Kennis, Jan; Crauwels, Dieter; Eiseb, Seth; Mahlaba, Themb’alilahlwa A.; Monadjem, Ara; Makundi, Rhodes H.; Katakweba, Abdul A. S.; Leirs, Herwig; Belmain, Steven R.
Differences in the ecological niche requirements among rodent species competing in the same habitat may result from differences in the use of one to three resources: space, time and food or some combination of these. Alternatively, differences in resource use utilization among animal species may simply reflect availability of food, and when food is limited, different animal species compete. In this study, the diet of two rodent pest species, Mastomys natalensis and Gerbilliscus vicinus, coexisting in fallow land in central Tanzania were studied to assess the degree of diet differentiation among them. Dietary niche breadth of G. vicinus was greater than that of M. natalensis in all stages of the maize cropping seasons. The rodent species studied overlapped considerably in the food items consumed ranging from niche overlap (Ojk) of 0.77–0.89. Grains/seeds featured high in the diet of M. natalensis while plant material occurrence was high in G. vicinus. These two food categories may have contributed to differences in diet partitioning, which may, in turn, facilitate their coexistence in fallow land.
Diversity and distribution of rodent and shrew species associated with variations in altitude on Mount Kilimanjaro, Tanzania
(Walter de Gruyte, 2008) Mulungu, L.S.; Makundi, Rhodes H.; Massawe, Apia W.; Machang'u, Robert S.; MbiJe, Nsajigwa
A total of 750 rodents and shrews were trapped in sev- eral sites on Mount (Mt.) Kilimanjaro and in two lowland sites between October 2002 and August 2003. Species diversity variations with altitude and their distribution were established. Diversity of species varied with vege- tation type, being highest in the forest and lowest in the lowland areas. The distribution patterns and species diversity of the rodents and shrews were also influenced by habitat complexity and heterogeneity. Species rich- ness was higher in the forest compared to the other areas. The study generally shows that the Mt. Kilimanjaro has high rodent and shrew species diversity and richness.
Dynamics of infestation and losses of stored maize due to the larger grain borer (Prostephanus truncatus Horn) and maize weevils (Sitophilus zeamais Motschulsky)
(2010-09) Makundi, Rhodes H.; Swila, Ntuli N.; Misangu, Robert N; Reuben, Shazia W.M.; Mwatawala, Maulid; Sikira, Anna; Kilonzo, Bukhet S; Lyimo, H.; Massawe, Apia W.; Ishengoma, Christine
The dynamics of infestation and losses of stored maize due to the larger grain borer (Prostephanus truncatus Horn) and maize weevils (Sitophilus zeamais Motschulsky) were investigated in Tanzania. In single species populations, significantly higher maize damage (P 0.05) was caused by P. truncatus (23.3%) compared to S. zeamais (6.4%). Weight losses caused by P. truncatus were higher (12.7%) than for S. zeamais (6.7%) under similar conditions. A higher proportion of P. truncatus in the initial infestation population led to significantly higher ( 0.05) maize damage compared to equal or higher proportions of S. zeamais. Irrespective of the initial number of S. zeamais, population size increased to levels higher than for P. truncatus. Maize losses in unimproved storage structures were480% compared to52.5% in improved structures under natural infestation. Inter-specific competition appeared to influence the dynamics of infestation, damage levels and weight losses. The first two months of storage were critical for damaging insect populations to build up.
Effect of land preparation methods on spatial distribution of rodents in crop fields
(Australian Centre for International Agricultural Research, 2003) Massawe, Apia W.; Leirs, Herwig; Rwamugira, W. P.; Makundi, Rhodes H.
A mark–capture–release (CMR) study was carried out in Morogoro, Tanzania, from April 1999 to August 2000 to investigate the effect of slashing and burning versus tractor ploughing on the population of rodents in agricultural fields. We found that the spatial distribution of individuals was significantly affected by the land preparation method. The coefficient of dispersion values (based on variance-to-mean ratio calculations) indicated that more animals clustered around the edges in tractor-ploughed fields whereas in the slashed-and-burnt fields, animals were randomly distributed. Before land preparation, animals were randomly distributed everywhere. This suggests that the slashing-and-burning practice does not affect the rodent population distribution in crop fields while tractor ploughing does affect rodents, probably by reducing cover and food availability or even by killing some individuals. Yet, it seems useful as a management tool when it is practised over a large area and if the surrounding fallow lands, which act as donor habitat, are cleared.
Evaluation of thiram and cinnamamide for protection of maize seeds against multimammate mice, Mastomys natalensis, in Tanzania
(2005) Ngowo, Victor H.; Mulungu, Loth; Lodal, Jens; Makundi, Rhodes H.; Massawe, Apia W.; Leirs, Herwig
Farmers in Tanzania consider rodents to be the major vertebrate pest of maize, especially at planting and seedling stages and annual losses are high. We evaluated the potential of two seed-dressing compounds, thiram and cinnamamide, as rodent repellents to protect maize against damage by multimammate rats, Mastomys natalen- sis. In laboratory tests, the two compounds showed a strong repellent effect against M. natalensis and thus the potential to protect maize seeds. The two compounds were evaluated in maize fields using Randomized Complete Block Design (RCBD) with three replications. The results show that these repellents are effective for protecting maize seeds against multimammate rats in the field, but in locations with high population of Tatera leucogaster, seedlings are still damaged after emergence. Therefore, in such locations, other control measures, including applica- tion of rodenticides just before seedling emergence may be necessary.
Farmer’s perceptions of rodents as crop pests : Knowl- edge, attitudes and practices in rodent pest management in Tanzania and Ethiopia
(Belg. J. Zool, 2005-12) Makundi, Rhodes H.; Bekele, Afework; Leirs, Herwig; Massawe, Apia W.; Rwamugira, Winnie; Mulungu, Loth S.
A study was conducted using a structured questionnaire to obtain information about the nature and extent of rodent damage to crops, farmer’s perceptions of crop pests and their knowledge, attitudes and practices to their management in Tanzania and Ethiopia. The study was carried out in five localities (Makuyu -Central Tanzania; Chunya-Southwest Tanzania; Ziway and Adami Tulu (south of Addis Ababa) and Gumer/Limmo-South-west of Addis Ababa, both in Central Ethiopia). In Tanzania, maize is the major crop, both for food and sale. Other crops are sorghum, rice, simsim, groundnuts and millet. In Central Ethiopia, farmers grow maize, sorghum, teff, beans, barley, wheat, potatoes and enset. The study showed that farmers in Tanzania and Ethiopia are well aware of rodent problems and considered them to be number one pest. Rodent problems are regular and maize is the most affected crop in Tanzania. In Ethiopia, maize, enset and potatoes are the most affected crops. Maize in Ethiopia and Tanzania is susceptible to rodent damage, most seriously at planting and seedling stage. Although different rodent control techniques are practiced in Tanzania, farmers prefer using rodenticides (68.7%) to other strategies. In Ethiopia, trap- ping, hunting and rodenticides are the most practised techniques for rodent control. Farmer’s attempts to control rodents in both countries are based on economic reasons and generally, rodent control is not undertaken when there are no crops in the fields. Farmers are responsible for rodent control activities in their individual fields. The study shows that farmers in Tanzania and Ethiopia are concerned with rodent infestation and are also aware of the critical growth stage when the crops are most susceptible. A lack of multiple rodent management methods and inadequate knowledge of appropriate and sustainable techniques appeared to be the main reasons for the over dependence on rodenticides, particularly in Tanzania. Therefore, this suggests that farmers require a strong extension input to man- age rodent problems
Influence of land preparation methods and vegetation cover on population abundance of Mastomys natalensis in Morogoro, Tanzania
(2005-12) Massawe, Apia W.; RWAMUGIRA, Winifrida; Leirs, Herwig; Makundi, Rhodes H.; Mulungu, Loth
A Capture-Mark-Release study was carried out in Morogoro, Tanzania, from April 1999 to April 2001 to investigate the effects of land preparation methods and cropping systems on population abundance of Mastomys natalensis in crop fields. Two land preparation methods (tractor ploughing; slash and burning) and two cropping systems (mono-cropping with maize; inter-cropping with maize and beans) were included in the study. The experi- mental design was a Complete Randomized Design with 2x2 factors, with two replicates. In slash and burn fields, rodent population abundance and distribution were strongly influenced by vegetation cover regardless of the type of cropping system. Higher rodent population peaks occurred in dense vegetation cover in slash and burn relative to tractor ploughed fields. In contrast, there were no obvious associations between vegetation cover and population abundance in the tractor ploughed fields, particularly in the mono-cropping system. A negative correlation between vegetation cover and population abundance of M. natalensis was obtained in fallow land surrounding the crop fields (r = -0.63; p ≤ 0.05). The results show that the effect of vegetation cover on population abundance of M natalensis in crop fields is strongly influenced by the type of land preparation methods. Tractor ploughing and clearance of fal- low land surrounding crop fields could be a useful method to reduce the invasion of crops by M. natalensis.
Prevalence of haemoparasites, leptospires and coccobacilli with potential for human infection in the blood of rodents and shrews from selected localities in Tanzania, Namibia and Swaziland
(African Zoology, 2012-02) Katakweba, Abdul A.S.; Mulungu, Loth S.; Eiseb, Seth J.; Mahlaba, Themb’alilahlwa A.; Makundi, Rhodes H.; Massawe, Apia W.; Borremans, Benny; Belmain, Steven R.
The prevalence of haemoparasites, leptospirosis and Yersinia pestis was investigated in rodents and shrews from Tanzania, Namibia and Swaziland. Blood smears originating from rodents and shrews from the three countries indicated the presence of Trypanosoma lewisi (72.7%; n =950), Bacillus spp. (25.6%; n =950), Borrelia sp. (0.01%; n =950) and bipolar coccobacilli (0.01%; n =950). The blood smears from Namibia (n =26) had no haemoparasites while only 1.33% (n =75) of those from Swaziland showed presence of T. lewisi. Leptospira interrogans was found in rodent blood sera from Tanzania in the following serogroup proportions (n =350): Icterohaemorrhagiae (10.29%), Pomona (2.86%), Hardjo (1.14%), Bullum (0.86%), Grippotyphosa (1.43%) and Canicola (1.14%). Serodiagnosis of antibodies against the F1 antigen of Y. pestis using the enzyme linked immunosorbent assay (ELISA) was negative for all the serum samples from central Tanzania, while two samples of serum from two species of rodents, Rhabdomys pumilio and Gerbilliscus leucogaster, collected in the Kavango Region of Namibia were positive. These results suggest an enzootic plague activity in this region in Namibia. It is concluded that zoonotic agents, that are infectious to humans, are prevalent in rodents and shrews in the three countries, and that local communities should apply rodent control measures to reduce the risk of human infections.
Relationship between sampling intensity and precision for estimating damage to maize caused by rodents
(Blackwell Publishing and IOZ/CAS, 2007) Mulungu, Loth S.; Massawe, Apia W.; Makundi, Rhodes H.; Leirs, Herwing
In this study we aimed to determine the relationship between sampling intensity and precision for estimating rodent damage. We used the systematic row sampling technique to provide data to achieve precision and accuracy in estimations of rodent damage in maize fields at the planting and seedling stages. The actual rodent damage to maize in 15 fields, each 0.5 ha in size, in Morogoro, Tanzania, was established at the seedling stage. These data were used to simulate the sampling intensities that would provide precision and accuracy. The variations between estimates were plotted against the sampling intervals. The results of this study show that the relationship between average standardized variances and sampling intervals is linear. The heterogeneous distribution of damage in some plots caused variations in the accuracy of the estimates between plots, but a sampling interval of five rows consistently produced estimates with a variance of less than 10%. We provide a standard curve that will allow a decision to be made on the sampling intensity as a function of required precision using the systematic row sampling technique in maize fields. Key words: rodents, sampling interval, simulation, standard curve, systematic row sampling.
Relationship between sampling intensity and precision for estimating damage to maize caused by rodents
(Blackwell Publishing and IOZ/CAS, 2007) Mulungu, Loth S.; Makundi, Rhodes H.; Massawe, Apia W.; Leirs, Herwig
In this study we aimed to determine the relationship between sampling intensity and precision for estimating rodent damage. We used the systematic row sampling technique to provide data to achieve precision and accuracy in estimations of rodent damage in maize fields at the planting and seedling stages. The actual rodent damage to maize in 15 fields, each 0.5 ha in size, in Morogoro, Tanzania, was established at the seedling stage. These data were used to simulate the sampling intensities that would provide precision and accuracy. The variations between estimates were plotted against the sampling intervals. The results of this study show that the relationship between average standardized variances and sampling intervals is linear. The heterogeneous distribution of damage in some plots caused variations in the accuracy of the estimates between plots, but a sampling interval of five rows consistently produced estimates with a variance of less than 10%. We provide a standard curve that will allow a decision to be made on the sampling intensity as a function of required precision using the systematic row sampling technique in maize fields.
Reproduction and population dynamics of Mastomys natalensis Smith, 1834 in an agricultural landscape in the Western Usambara Mountains, Tanzania
(Blackwell Publishing and IOZ/CAS, 2007) Makundi, Rhodes H.; Massawe, Apia W.; Mulungu, Loth S.
The multimammate rat, Mastomys natalensis Smith 1834, is a dominant species in agro-ecosystems in Sub-Saharan Africa, but adapts quickly to changes in non-agricultural landscape, particularly woodlands and forests. In this study we report on reproduction and population dynamics of M. natalensis in deforested high elevation localities in the Usambara Mountains, north-east Tanzania. We conducted Capture-Mark-Recapture studies in 2002-2004, and established that reproduction of M. natalensis takes place in the extended wet season between February and June, and the population density peaks in June-August. Reproduction cease in July to January and population density drops from July onwards. Reproduction and population density fluctuations are linked to the duration and amount of rainfall. In years when rainfall was below average and the wet season was short, the population density was significantly lower (below 10 animals/ha and 60 animals/ha in 2003 and 2004 respectively, compared to >100 animals/ha in 2002 when rainfall was above the seasonal average) (Fdf 2, 13= 9.092, p<0.01 for in between years variations and Fdf 12, 15 = 5.389, p<0.01 for effect of cumulative annual rainfall on population density). These densities were much lower than in the lowland savannah habitats in central and southwest Tanzania. A comparison between the farmland/fallow mosaic fields and agro-forestry areas showed higher population densities in the former, which have similarities to the preferred habitats in the lowland savannahs. The increasing abundance of M. natalensis in the Usambara could have some consequences: M. natalensis is major pest and is involved in the plague cycle in the western Usambara Mountains. Mastomys natalensis is also a strong competitor and the impact on endemic rodent species, e.g. Lophuromys flavopunctatus and Praomys delectorum is unknown.
Rodent population fluctuations in three ecologically heterogeneous locations in northeast, central and south- west Tanzania
(Belg. J. Zool, 2005-12) Makundi, Rhodes H.; Massawe, Apia W.; Mulungu, Loth
Rodent population fluctuations and breeding patterns were investigated at localities in South-west, Central and North-east Tanzania. The three localities are ecologically heterogeneous in vegetation types, rodent species diversity, rainfall pattern and altitude. Capture-Mark-Release studies were conducted in 2001-2003 to com- pare rodent species composition and population trends. In North-eastern Tanzania, species composition is diverse and includes Mastomys natalensis, Lophuromys flavopunctatus, Grammomys dolichurus, Arvicanthis nairobae, Praomys delectorum and Mus sp.. Five species were recorded in South-western Tanzania namely, M. natalensis, Graphiurus murinus, Saccostomus elegans, Tatera leucogaster and Steatomys pratensis. In Central Tanzania M. natalensis was dominant, but a few Lemniscomys griselda were captured. Rodent abundance fluctuations were dis- tinctively seasonal, especially for M. natalensis in the three localities and T. leucogaster in South-west Tanzania. In North-eastern Tanzania, L. flavopunctatus, G. dolichurus, A. nairobae and P. delectorum had low, but relatively sta- ble populations throughout the year. In South-west Tanzania, population peaks of M. natalensis and T. leucogaster were reached in the dry season (June-September). In Central Tanzania, breeding of M. natalensis was seasonal, with highest population abundance during July-November. Female M. natalensis were reproductively active in January- May and males had scrotal testes in December-June. No males were sexually active during July-November. Female T. leucogaster in South-western Tanzania were reproductively active during November-April/May whereas sexually active males appeared in the population during November-March. In view of the observed rodent population fluctu- ations and breeding patterns, recommendations are given for pragmatic rodent control in South-west and Central Tanzania and for plague in North-eastern Tanzania
Soil type limits population abundance of rodents in crop fields: case study of the multimammate rat Mastomys natalensis Smith, 1834 in Tanzania
(Blackwell Publishing, 2008) Massawe, Apia W.; RWAMUGIRA, Winnie; LEIRS, Herwig; Makundi, Rhodes H.; Mulungu, Loth; Ngowo, V.; Machang'u, Robert S.
Studies of populations of the multimammate rat Mastomys natalensis in Morogoro, Tanzania, show that soil texture appears to influence the population abundance and distribution of these rats in agricultural fields. The lowest rodent population abundance was found on sandy clay soils (F (2, 5) = 8.42; P = 0.025). The population abundances of M. natalensis on sandy clay loam and sandy loam soils did not differ significantly (P ≤ 0.05), possibly because these soils have a very similar texture. The results of this study suggest that M. natalensis prefers loam-textured soils with a high percentage of sand, which are probably better than clay soils for burrowing and nesting, particularly in the rainy season. The lower preference for clay soils is probably related to the poor aeration in these soils and the waterlogging that occurs during the wet season.
Spatial and temporal population dynamics of rodents in three geographically different regions in Africa: implication for ecologically-based rodent management
(Tailor & Francis, 2015-04-20) Massawe, Apia W.; Mulungu, Loth S.; Makundi, Rhodes H.; Dlamini, Nomfundo; Eiseb, Seth J.; Kirsten, Frikkie; Mahlaba, Themb’alilahlwa; Malebane, Phanuel; Maltitz, Emil Von; Monadjem, Ara; Taylor, Peter; Tutjavi, Vassana; Belmain, Steven R.
As part of a three-year study to develop ecologically-based rodent management (EBRM) in southern Africa, a capture–mark–recapture study was carried out in Tanzania, Namibia and Swaziland to establish the demographic patterns and population dynamics of rodents. Two study grids were established in each country. In Tanzania, ten species of rodents and one shrew (Crocidura sp.) were identified in the study area. The rodent species consisted of Mastomys natalensis, Aethomys chrysophilus, Arvicanthis neumanni, Gerbilliscus vicina, Acomys spinosissimus, Lemniscomys griselda, Lemniscomys zebra, Rattus rattus, Graphiurus sp. and Mus minutoides. Mastomys natalensis was dominant and contributed more than 70% of the captures. In Namibia, five species were captured, namely Mastomys natalensis, Gerbilliscus leucogaster, Saccostomus campestris, Mus minutoides and Steatomys pratensis. Mastomys natalensis contributed about 50% of the captures. In Swaziland, only M. natalensis was captured in the study grids. There was a clear pattern in the population dynamics, with breeding confined to the wet seasons in the three countries. Mastomys natalensis was the dominant pest species, for which EBRM should focus on. The highest population density of M. natalensis occurred during and after the rains, which coincided with the most susceptible phenological stage of crops. The breeding seasonality and density fluctuations observed in the three countries conform with observations made elsewhere in Africa, which support the hypothesis that rainfall events promote primary productivity on which murid rodents depend. Development of EBRM in these countries will be determined by the local conditions and how they influence the demographic processes of the rodent populations. EBRM should make use of the available ecological knowledge of the local rodent pest species and the focus should be on (ecological) management practices applicable at the community level including community based intensive trapping, field hygiene, removing cover and sources of food for rodents.
Species diversity and population dynamics of rodents in a farm-fallow field mosaic system in Central Tanzania
(2009) Makundi, Rhodes H.; Massawe, Apia W.; Mulungu, Loth S.; Katakweba, Abdul
A Capture-Mark-Recapture study was undertaken in Central Tanzania to compare variations in community structure and population dynamics of rodents in two types of habitats. The study was conducted in fallow field mosaic habitat dominated by perennial and annual grasses (grid BEA) and a more heterogeneous habitat (grid BEB) which was previously woodland cleared of most trees with vegetation dominated by shrubs, bushes, scattered trees and perennial grass. The relative abundance of rodents in BEA was: Mastomys natalensis (73.5%) > Aethomys chrysophilus (8.9%) > Gerbilliscus vicina (7.3%) > Arvicanthis neumanni (6.1%) > Acomys spinosissimus (4.1%) and for grid BEB: M. natalensis (67.6%) > G. vicina (11.2%) > A. neumanni (10.3%) > A. chrysophilus (7.6%) > A. spinosissimus (2.9%). Graphiurus sp., Mus minutoides, Saccostomus mearnsi, Lemniscomys striatus and L. griselda were rare and only occasionally trapped in BEB. Spatial variations in population density were non-significant except for A. chrysophilus. Significant temporal variations within grids were observed, with synchrony of population peaks for some species. The rare species boosted species richness of grid BEB rather artificially, without significantly contributing to higher species diversity. Temporal variations in Simpson’s Diversity indices between grids were non-significant except for three out of twenty-one trapping sessions.