Species composition,abundance and habitat association of non-volant small mammals in Gibe Sheleko National Park,southwestern Ethiopia

The objective of this study was to assess the species composition, abundance and habitat association of non-volant small mammals from grassland, Acacia woodland, farmland, riverine forest, bushland and wooded grassland habitats in Gibe Sheleko National Park, southwestern Ethiopia. Data were collected using 49 Sherman live traps in 70 × 70 m sized girds and visual observations from December 2018 to August 2020. A total of 937 small mammals belonging to 10 species were captured and directly identified. The identified small mammal species and their relative abundance include Arvicanthis niloticus (7.04%), Crocidura olivieri (1.92%), Grammomys dolichurus (3.84%), Lemniscomys striatus (10.25%), Mastomys awashensis (24.55%), Mastomys natalensis (33.83%), Mus tenellus (0.85%), Myomys fumatus (6.30%), Rattus rattus (4.70%) and Stenocephalemys albipes (6.72%). Hystrix cristata, Xerus rutilus and Tachyoryctes splendens were documented through observation. The highest number of species (6) was registered at farmland and wooded grassland followed by bushland and riverine forest (5) and Acacia woodland and grassland (4). Lemniscomys striatus, M. awashensis and M. natalensis were common in all habitats. More, 216 (23.05%) individuals were recorded in farmland, while the least, 111 (11.85%) were recorded in Acacia woodland. The study area has various topographical land settings additional study is needed using different traps.     

Distribution of small rodents and shrews in a lowland rain forest zone of Nigeria, with observations on their reproductive biology

This paper describes the habitat preferences of small rodents and shrews from April 1984 to March 1985 in four types of vegetation in a lowland rain forest zone of Nigeria. The vegetation types were high forest, scrub, farmlands and teak plantations in Ogba Forest Reserve, Nigeria. A collection of 359 small mammals, consisting of six species of small rodents and four species of shrews, was made in the study area. The small rodents and their percentage composition were Mus musculoides (26.2%), Praomys tullbergi (16.2%), Mastomys natalensis (7.0%), Lophuromys sikapusi (4.5%), Lemniscomys striatus (2.5%), and Arvicanthis niloticus (1.1%). The shrews were Crocidura nigeriae (19.5%), C. crossei (12.3%), C.grandiceps (7.8%) and C. ftavescens manni (3.1%). The vegetational distribution of the small rodents and shrews is discussed. In the high forest, seven species of small mammals were caught; these were Crocidura nigeriae, C. crossei, C.grandiceps, C.flavescens manni, Mus musculoides, Praomys tullbergi and Lophuromys sikapusi. Mus musculoides, Crocidura nigeriae and Praomys tullbergi were more abundant in the high forest. All the species of small mammals recorded in the study area, except Arvicanthis niloticus, were found in the scrub. In the farmlands, all ten species of small mammals were trapped. Mus musculoides was the commonest species in the farmlands. Three species of shrews, Crocidura crossei, C. grandiceps and C.flavescens manni, and also two species of small rodents, Mus musculoides and Mastomys natalensis were caught in the teak plantation. The reproductive data for Mus musculoides, Crocidura nigeriae and Praomys tullbergi show that breeding in these species occurs throughout most months of the year. Fecundity appears to be maximal in the wet season in Mus musculoides and Crocidura nigeriae and in the dry season in the case of Praomys tullbergi.     

Species composition,abundance and habitat association of rodents and insectivores from Chilalo–Galama Mountain range,Arsi, Ethiopia

A study on the ecology of rodents and insectivores on Mount Chilalo and the Galama Mountain range was conducted during August, 2007–April, 2008. Study grids were marked in nine randomly selected habitats. Sherman live traps and snap traps were used to capture the small mammals. A total of 2525 (including recaptures) individual rodents and insectivores were captured in 5488 (Sherman) and 1590 (snap) trap‐nights. Among the live‐trapped animals, 2037 (96.2%) and 80 (3.8%) were rodents and insectivores, respectively, that comprised 17 species. These were as follows: Arvicanthis abyssinicus, Arvicanthis blicki, Arvicanthis dembeensis, Lophuromys flavopunctatus, Lophuromys melanonyx, Mastomys natalensis, Mus mahomet, Otomys typus, Rattus rattus, Stenocephalemys albipes, Stenocephalemys albocaudata, Stenocephalemys griseicauda, Crocidura glassi, Crocidura flavescens and Crocidura thalia. Tachyoryctes splendens and Hystrix cristata were sighted but not captured. Endemics to Ethiopia constituted 60% of the trapped small mammals. Lophuromys flavopunctatus was the most abundant and widely distributed rodent species, while M. mahomet was the least. The altitudes between 3301 and 3400 m asl had the highest species composition and abundance although it is second in number of catches per trap‐nights. The majority of rodents and insectivores were associated with montane forest habitat, whereas the least were in the shrubland. Anthropogenic effects were witnessed affecting the distribution of small mammals.     

Population dynamics of small mammals at Mlawula, Swaziland

Population density, biomass and composition of a small mammal community in an Acacia nigrescens savanna were studied over 12 months from August 2000. The community consisted of Mus minutoides (A. Smith 1834), Mastomys natalensis (A. Smith 1834), Lemniscomys rosalia (Thomas 1904), Crocidura hirta (Peters 1952), Steatomys pratensis (Peters 1846); and on one occasion, Graphiurus murinus (Desmarest 1822) was caught. M. minutoides was the dominant species in the site. Species richness was found to vary significantly with the time of the year. The density of M. minutoides was significantly high in winter and low in the other seasons, the ratio of males to females was found to be equal, and pregnant females were caught from November to May. The biomass of small mammals in the area (also density and numbers) was generally low (mean biomass 212 g ha^?1). The occurrence of new individuals in catches remained high throughout the study, suggesting a high mortality or emigration rate or a combination of the two.     

Species diversity and population dynamics of rodents in a farm‐fallow field mosaic system in Central Tanzania

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.     

Species composition,relative abundance and habitat association of small mammals along the altitudinal gradient of Jiren Mountain,Jimma, Ethiopia

To document the species composition, relative abundance and habitat association of small mammals, wet and dry season surveys were conducted along the altitudinal gradient of Jiren Mountain, Jimma area, Ethiopia. Sherman traps were used to capture small mammals from the six habitats: wetland, mixed plantation, open shrub, eucalyptus plantation, montane grassland and coffee plantation. The 393 trap nights, from the six habitat types, yielded 106 individual small mammals of tweleve species. The trapped rodents were Lophuromys flavopunctatus, Stenocephalemys albipes, Desmomys harringtoni, Mus mahomet, Lemniscomys barbarous, L. striatus, Tachyoryctes splendens, Mastomys natalensis and the insectivores Crocidura fumosa and C. turba. Two species of rodents Hystrix cristata and Helioscuirus gambianus were observed. Lophuromys flavopunctatus and S. albipes contributed 83.8% of the total capture. L. flavopunctatus, S. albipes and D. harringtoni were distributed in all habitats and gradients. T. splendens was captured from montane habitat, while the zebra mice were associated with the lower altitude habitats. Lophuromys flavopunctatus and M. natalensis extended their range deep into the coffee plantation habitats. Uncontrolled vegetation exploitation of the mountains for timber production and fire wood collection are the major threats. Conservation of the area to reduce the anthropogenic pressure is essential.     

Ecology of a typical West African Sudanian savannah rodent community

The small‐mammal community of a typical Sudanian savannah area of south‐eastern Senegal was studied by way of intensive sampling at the beginning (July) and at the end (November) of the rainy season. A total of 5931 trapnights and 200 pitfallnights yielded 767 small mammals, including 757 rodents of 12 species, as well as a few shrews and hedgehogs. Accumulation curve indicated that the rodent community was well sampled. Murine rodents were far more numerous than gerbilline rodents, and among them, Mastomys erythroleucus was the dominant species, being caught in high numbers in all habitats. Arvicanthis niloticus and Praomys daltoni were also abundant, followed by Mastomys natalensis and Gerbilliscus guineae. Abundances were high at the beginning of the rainy season when reproductive activity was low in all species. At the end of the rainy season, murine rodents were actively involved in reproduction, while gerbilline rodents were at their lowest density. Significant changes in relative abundance among habitats (including human dwellings) were observed between periods in some species, suggesting seasonal trends in habitat preferences. This may help species coexistence in this species‐rich rodent community, in an area likely to be submitted to significant habitat alterations in the years to come.     

Species composition and community structure of small pest rodents (Muridae) in cultivated and fallow fields in maize‐growing areas in Mayuge district,Eastern Uganda

相似文献   

Abundance and diversity of rodents at the human–wildlife interface in Western Serengeti, Tanzania

Rodent species abundance and diversity in Western Serengeti are evaluated and discussed in relation to different levels of conservation status [Unprotected Area (UA), Game Reserve (GR) and National Park (NP)] and broad site differences in human livelihood activities. A total of 2170 individuals, spread over 16 rodent species, were caught in a capture‐mark‐recapture study which covered both the dry and wet seasons. The more humid site (Tabora B) in the northern part of Serengeti had the highest diversity of rodents followed by the Mihale site at the western extension. The driest site at Robanda had the lowest overall species diversity. Diversity also varied between the three levels of conservation status whereby the UA had the least diversity while the NP, which enjoyed the highest level of conservation status, had the highest diversity of rodents. Unprotected Area and NP plots at Tabora B showed a rodent species similarity index of 40%; all the other paired plots scored over 50% similarity indices, suggesting that, within a site, species composition did not vary significantly between the three levels of conservation status. The Robanda site had the highest (56%) overall abundance of rodents; Mihale and Tabora B sites had about the same level of rodent abundance (20 and 24% respectively). For the Mihale site, Mastomys natalensis ranked first followed by Arvicanthis niloticus and Tatera robusta, each of which contained 40, 38 and 16%, respectively, of all individuals caught at the site. For the Robanda site, the figures were 66%A. niloticus, 22%M. natalensis and 9%T. robusta; while for the Tabora B site the scores were 37%M. natalensis, 18%T. robusta and 11%Lemniscomys barbarus. The differences in diversity, species composition and population abundance appear to result largely from physiognomic vegetation types, and habitat perturbations caused by livelihood activities in Western Serengeti.     

Community ecology of the terrestrial small mammals of Zakouma National Park,Chad

The terrestrial small mammal community of the Zakouma National Park (Chad) was assessed by live trapping in various habitats during the dry season. Nearly 3000 trap-nights yielded 505 captures of nine rodent and two shrew species, making up a representative small mammal community for the Sudanian savanna biotic zone. Murine rodents of the genusMastomys dominated, withM. erythroleucus andM. cf.kollmannspergeri occuring at similar abundances. The former was widespread and especially abundant in habitats with high tree cover. The latter was more localized, predominantly in annually flooded habitats characterized by a clay-rich soil, often withAcacia seyal as the main vegetation. Population structure differed between the two species, suggesting distinct reproductive strategies possibly linked with habitat preferences: theM. erythroleucus population comprised mainly young, immature individuals, whereasM. cf.kollmannspergeri was represented by older individuals, a significant fraction of which had already reproduced.Taterillus congicus andTatera kempi (gerbilline rodents), together withLemniscomys zebra, were mainly found in more open habitats with sand-rich soils.Arvicanthis niloticus, Acomys cf.johannis, Mus mattheyi andXerus erythropus were the other rodents captured, whereas shrews were represented byCrocidura fulvastra andSuncus sp.     

On the morphology of spermatozoa in some African murines (Rodentia, Muridae): the taxonomic and phylogenetic aspects

A comparative analysis of sperm-head morphology and measurements in 17 species from nine genera of African Murinae: Rattus rattus, Mastomys coucha, M. huberti, M. erythroleucus, Mastomys sp. 2, Praomys albipes, P. fumatus, Mus mahomet, Arvicanthis somalicus, A. abyssinicus, A. dembeensis, Arvicanthis sp., Lemniscomys macculus, Pelomys harringtoni, Acomys cahirinus, Acomys sp., Uranomys ruddi, was carried out. Spermatozoa of all examined species are of the same basic type. They consist of an asymmetrical head, falciform or scythelike in shape, and a tail attached to the ventrocaudal surface of the head. There are great interspecific differences in sperm morphology and size. The significance of this variation for estimation of taxonomic aspects and phylogenetic relationships among the species, as well as between them and other groups, is discussed. The sperm morphology supports a close evolutionary relationship among the genera Lemniscomys and Arvicanthis. It also indicates that Pelomys is distinctive. The relationships between Acomys and Uranomys are discussed.     

Diversity and distribution of murid rodent populations between forest and derived savanna sites within south western Nigeria

Southward encroachment of the derived savanna zone with its attendant denudation of the rainforest in Nigeria adversely affects the diversity and distribution of mammals, particularly murid rodents. This study was carried out to establish the identities of murid rodent populations and to compare their diversity between forest and derived savanna sites within south western Nigeria. Identification of captured specimens was carried out by multivariate statistics of body and skull measurements, and also by analysis of certain discrete characters. Six species were identified: Praomys tullbergi, Hylomyscus stella, Mastomys natalensis, Arvicanthis rufinus, Lemniscomys striatus and Lophuromys sikapusi. Forest sites possessed a higher Shannon’s diversity index (1.685) than the derived savanna sites (0.978), containing a higher number of taxa and larger abundance of murid rodents. This underscores the negative impact that encroachment of the derived savanna has upon diversity of animals in areas that were once forest.     

Diversity,dynamics and reproduction in a community of small mammals in Upper Guinea,with emphasis on pygmy mice ecology

As part of a large survey on reservoirs of Lassa fever in Guinea, three villages were investigated in high endemic zone, close to Sierra Leone border. Biodiversity of the small mammal community is presented in this study through a standardized trapping in houses, cultivations and forest. Identification of the small mammals was based on morphology and by molecular technique for sibling species. Of the 1123 specimens collected in 2003–2005, we identified seventeen species (thirteen Muridae, four Soricidae), leading to high diversity (Shannon index = 1.6–1.8) and high equitability (evenness index = 0.7–0.8) in cultivations and forest. In houses conversely, the rodent community was dominated by Mastomys natalensis (95–98%), leading to low diversity and equitability. Dynamics and reproduction were investigated in two species of pygmy mice, Mus mattheyi and Mus minutoides, two species of Praomys, P. daltoni and P. rostratus, and in Mastomys erythroleucus. The pygmy mice were abundant in cultivations in early rainy season, and reproduced from rainy to dry season. Praomys daltoni was also found more abundant in cultivations and seemed to reproduce between rainy and dry season, whereas P. rostratus preferred forest and cultivations in late rainy season, and reproduced throughout the year. Finally, M. erythroleucus was more abundant in forest in dry season, and seemed to reproduce from late rainy to dry season. This species had a low occurrence (6.5%) in the Faranah’s zone, and probably lived at its southern limit in Guinea. The presence of other Murinae, such as M. natalensis, Praomys spp as possible competitors in the same habitats, is discussed. For the first time, this study relates population biology of pygmy mice with molecular identification.     

Small mammal diversity and dynamics within Nigeria,with emphasis on reservoirs of the lassa virus

Nigeria has a rich small mammal community, with several species implicated as carriers of zoonotic microbes such as the Lassa virus (LASV). We sought to elucidate the diversity and distribution of these animals (including known LASV reservoirs) geographically, habitat-wise and seasonally. Our DNA-assisted survey detected at least 19 small mammal species amongst 790 specimens. Diversity indices were similar between ecological zones and also between endemic and non-endemic areas for Lassa fever. Mastomys natalensis, the most renowned LASV host, was present in eight out of nine localities sampled. We also described the spatial occurrence of other known LASV hosts such as M. erythroleucus and Hylomyscus pamfi, including carriers of LASV-like arenaviruses such as Mus (Nannomys) spp. The most numerous rodents (Mastomys natalensis, M. erythroleucus, and Praomys daltoni) were captured mainly inside human dwellings. Reproductive activity occurred throughout the year, but led to population peaks for M. natalensis in the dry season and for M. erythroleucus and P. daltoni in the rainy season. Extensive geographic distribution of LASV rodent reservoirs, with population peaks in different seasons, shows that the risk of rodent-to-human transmission of LASV is greater than currently realized.     

Comparative study of Spanish and Italian terrestrial small mammal coenoses from different biotopes in Mediterranean peninsular tip regions

A comparison of terrestrial small mammal coenoses belonging to nine different biotopes in the tips of the Iberian and Italian peninsulas was carried out using the pitfall trapping method. The influence of both habitat type and peninsular effect on composition of small mammal coenoses was analysed. In Southern Italy, 203 specimens belonging to seven species were trapped: Suncus etruscus (Savi, 1822), Crocidura suaveolens (Pallas, 1811), C. leucodon (Hermann, 1780), Microtus savii (de Sélys-Longchamps, 1838), Apodemus sylvaticus (L., 1758), A. flavicollis (Melchior, 1834) and Mus musculus domesticus Schwarz & Schwarz, 1943. In Southern Spain 428 specimens belonging to five species were trapped: Suncus etruscus, Crocidura russula (Hermann, 1780), Microtus duodecimcostatus (de Sélys-Longchamps, 1839), Apodemus sylvaticus and Mus spretus Lataste, 1883. The relative density of small mammals occurring in the nine Spanish sampling stations was twice that recorded in the Italian stations; however the number of species recorded in the different biotopes show similar mean values, ranging from three to five in Andalusia and from three to six in Calabria. Apodemus sylvaticus was the dominant species in the Calabrian stations, whereas Crocidura russula prevailed in Andalusia. The biotic diversity values are very similar in the Calabrian and Andalusian biotopes. By contrast, the Insectivora/Rodentia ratio was always higher in Andalusia. The more xerophytic biotopes showed greater similarities between the communities in Southern Spain and Southern Italy, while the cooler biotopes differed between these two peninsulas.     

Effects of urban habitat fragmentation on common small mammals: species versus communities

There is an increasing interest in understanding how species respond to the modifications of habitat attributes in urban areas. Patterns in the occurrence and abundance of small mammal communities in 15 isolated patches of remnant natural and semi-natural habitat of Porto Metropolitan Area (Portugal) were assessed against environmental characteristics (from both the patch and the surrounding matrix) of each patch using multiple regressions and canonical correspondence analysis. Four species of common small mammals were found: wood mouse (Apodemus sylvaticus), greater white-toothed shrew (Crocidura russula), Algerian mouse (Mus spretus) and house mouse (Mus musculus). Our results showed that both relative abundance and species richness were negatively affected by urbanization. The species richness also displayed a negative association with the increase of forest around the patch but relative abundance showed the opposite trend. At the species level, the relative abundance of A. sylvaticus and C. russula showed a negative association with urbanization. Our results reveal that these two species also benefit from a mosaic of habitats and pervious areas in the surrounding matrix. The relative abundance of M. spretus and M. musculus showed a negative effect of forest area around the patch. Understanding how the increase of urbanization affects small mammals will be particularly useful for the managers of urban landscapes, as these animals occupy a pivotal position in the ecosystems.     

Toxoplasmosis seroprevalence in urban rodents: a survey in Niamey,Niger

A serological survey of Toxoplasma gondii was conducted on 766 domestic and peridomestic rodents from 46 trapping sites throughout the city of Niamey, Niger. A low seroprevalence was found over the whole town with only 1.96% of the rodents found seropositive. However, differences between species were important, ranging from less than 2% in truly commensal Mastomys natalensis, Rattus rattus and Mus musculus, while garden-associated Arvicanthis niloticus displayed 9.1% of seropositive individuals. This is in line with previous studies on tropical rodents - that we reviewed here - which altogether show that Toxoplasma seroprevalence in rodent is highly variable, depending on many factors such as locality and/or species. Moreover, although we were not able to decipher statistically between habitat or species effect, such a contrast between Nile grass rats and the other rodent species points towards a potentially important role of environmental toxoplasmic infection. This would deserve to be further scrutinised since intra-city irrigated cultures are extending in Niamey, thus potentially increasing Toxoplasma circulation in this yet semi-arid region. As far as we are aware of, our study is one of the rare surveys of its kind performed in Sub-Saharan Africa and the first one ever conducted in the Sahel.     

First Detection of Mycobacteria in African Rodents and Insectivores, Using Stratified Pool Screening

With the rising number of patients with human immunodeficiency virus (HIV)/AIDS in developing countries, the control of mycobacteria is of growing importance. Previous studies have shown that rodents and insectivores are carriers of mycobacteria. However, it is not clear how widespread mycobacteria are in these animals and what their role is in spreading them. Therefore, the prevalence of mycobacteria in rodents and insectivores was studied in and around Morogoro, Tanzania. Live rodents were trapped, with three types of live traps, in three habitats. Pieces of organs were pooled per habitat, species, and organ type (stratified pooling); these sample pools were examined for the presence of mycobacteria by PCR, microscopy, and culture methods. The mycobacterial isolates were identified using phenotypic techniques and sequencing. In total, 708 small mammals were collected, 31 of which were shrews. By pool prevalence estimation, 2.65% of the animals were carriers of mycobacteria, with a higher prevalence in the urban areas and in Cricetomys gambianus and the insectivore Crocidura hirta. Nontuberculous mycobacteria (Mycobacterium chimaera, M. intracellulare, M. arupense, M. parascrofulaceum, and Mycobacterium spp.) were isolated from C. gambianus, Mastomys natalensis, and C. hirta. This study is the first to report findings of mycobacteria in African rodents and insectivores and the first in mycobacterial ecology to estimate the prevalence of mycobacteria after stratified pool screening. The fact that small mammals in urban areas carry more mycobacteria than those in the fields and that potentially pathogenic mycobacteria were isolated identifies a risk for other animals and humans, especially HIV/AIDS patients, that have a weakened immune system.     

Movement Patterns of Small Rodents in Lassa Fever-Endemic Villages in Guinea

The Natal multimammate mouse (Mastomys natalensis) is the reservoir host of Lassa arenavirus, the etiological agent of Lassa fever in humans. Because there exists no vaccine for human use, rodent control and adjusting human behavior are currently considered to be the only options for Lassa fever control. In order to develop efficient rodent control programs, more information about the host’s ecology is needed. In this study, we investigated the spatial behavior of M. natalensis and other small rodents in two capture-mark-recapture and four dyed bait (Rhodamine B) experiments in Lassa fever-endemic villages in Upper Guinea. During the capture-mark-recapture studies, 23% of the recaptured M. natalensis moved between the houses and proximate fields. While M. natalensis was found over the entire study grid (2 ha), other rodent species (Praomys daltoni, Praomys rostratus, Lemniscomys striatus, Mus spp.) were mostly trapped in the surrounding fields. Distances between recapture occasions never exceeded 100 m for all rodent species. During the dyed bait experiments, 11% of M. natalensis and 41% of P. daltoni moved from the fields to houses. We conclude that commensal M. natalensis easily moves between houses and proximate fields in Guinea. We therefore consider occasional domestic rodent elimination to be an unsustainable approach to reduce Lassa virus transmission risk to humans, as M. natalensis is likely to reinvade houses quickly from fields in which rodents are not controlled. A combination of permanent rodent elimination with other control strategies (e.g., make houses rodent proof or attract predators) could be more effective for Lassa fever control, but must be further investigated.     

Seasonal dynamics of macrohabitat use by small mammals in the Okavango Delta,Botswana: implications for landscape‐level disturbance resilience

In a changing climate, it is imperative to understand potential ecosystem resilience at all taxonomic levels. I compare seasonal small mammal utilization of woodlands (tree islands) and grasslands in the Okavango Delta, Botswana, to elucidate macrohabitat relationships and to test whether the two macrohabitats are similar in their ability to serve as a source of colonizers for the other after disturbance. Capture–mark–recapture data revealed that abundances for Dendromus mesomelas and Gerbilliscus leucogaster were higher in grasslands than tree islands, while Mus indutus abundance appeared higher in the grasslands in the dry season but roughly equal in the rainy season. Mastomys spp. and Steatomys pratensis maintained low levels in the grassland habitat throughout the year and experienced a population peak in the tree island habitat during the rainy season. There were no significant differences in sex ratio, mean mass or breeding condition. Dominance and total biomass were higher in the grasslands with the trend more pronounced in the rainy season. Terrestrial small mammals in the Okavango Delta employ differing strategies in macrohabitat selection and some exploit tree islands when herbaceous cover is present. Metacommunity dynamics exist for some species, and both habitats can serve as a source of colonizers under certain conditions.