Elevational Distribution and Ecology of Small Mammals on Africa’s Highest Mountain

Mt Kilimanjaro is Africa’s highest mountain, and an icon for a country famous for its mammalian fauna. The distribution and abundance of small mammals on the mountain are poorly known. Here we document the distribution of shrews and rodents along an elevational gradient on the southeastern versant of Kilimanjaro. Five sites were sampled with elevational center points of 2000, 2500, 3000, 3500 and 4000 m, using a systematic methodology of standard traps and pitfall lines, to inventory the shrews and rodents of the slope. Sixteen species of mammal were recorded, including 6 shrew and 10 rodent species, and the greatest diversity of both was found at 3000 m, the elevational midpoint of the transect. No species previously unrecorded on Kilimanjaro were observed. Two genera of rodents that occur in nearby mountains (Hylomyscus and Beamys) were not recorded. Myosorex zinki, the only mammal endemic to Mt. Kilimanjaro, which previously was known by only a few specimens collected in the ericaceous or moorland habitat, was found in all but one (the lowest) of the sites sampled, and was one of the most widespread species of small mammal along the gradient. Two shrews (Crocidura allex and Sylvisorex granti) and one rodent (Dendromus insignis) were found throughout the entire transect, with Dendromus being observed at our highest trap point (4240 m). As in similar faunal surveys on other mountains of Tanzania, rainfall influenced the sample success of shrews, but not rodents. Trap success for rodents at 3500 m was notably low. This study contributes further justification for the conservation of the forest habitat of Mt. Kilimanjaro.     

Habitat preferences and biomasses of small mammals in Swaziland

This paper describes the distribution and abundance of small mammals in Swaziland in relation to quantified habitat features. Eighteen habitat sites were sampled at seven different locations in all four geographical regions of Swaziland. Small mammal diversity (as described by the Shannon diversity index) was positively correlated with vegetation density. A total of twelve species of rodents and seven species of shrews were captured; however, only six species were caught at more than three sites. Small mammal biomasses and densities were highest at the highveld and middleveld sites. Tall grassland at all elevations supported a high diversity of small mammals. Highveld montane forest supported a high biomass and diversity of species, while no species were captured in moist forest in the Lubombo mountains.     

Soil zoology II: Colonization,distribution, and abundance of terrestrial Heteroptera in open landscapes of former brown coal mining areas

In the post-mining landscape of Lower Lusatia (eastern Germany), four mining areas were studied with respect to distribution and abundance of terrestrial Heteroptera. Colonization dynamics and formation of species communities in devasted open areas with different environmental conditions were investigated. In total, 127 species were found in 30 sampling sites, representing about 30% of all species of the state of Brandenburg. The ratio between purely phytophagous and mainly zoophagous species in younger (<20 years) and older sites (>20 years) did not differ much; the ratio between purely macropterous and partly brachypterous species was higher in younger sites. Macropterous species are able to colonize the sites more rapidly. Correspondence and cluster analyses revealed that community patterns are mainly determined by the architecture of the vegetation. Herb cover, grass cover, vegetation density and height, relation of grass versus herb dominance explained most of the community variances, while soil parameters and age of sites were of minor importance. Species number of Heteroptera is also strongly influenced by the plant species composition of sites. Except of young pioneer stages no significant differences in species number between undisturbed and disturbed sites were detected. Younger and older sites differed only slightly in species number of Heteroptera. Colonization by numerous species takes place rather rapidly, depending on the formation of special features of the vegetation and on the species pool of the surrounding area.     

Effects of environmental and temporal factors on Glomeromycotina spores in sand dunes along the Gulf of Valencia (Spain)

AMF symbiosis in sand dunes is the key for maintenance of stable vegetation. The main goal of this work was to determine the effects of environmental and temporal factors on AMF living in sand dunes (Gulf of Valencia, Spain). Soil samples were collected seasonally at 6 sites, during 2 yrs, from three habitats and four plant species and the frequency and relative abundance of AMF was examined. AMF were more frequent in mobile than in embryonic dunes, in spring and in sites with old vegetation. Ten AMF species were identified, their distribution depending mainly on the anthropogenic disturbance of the site. Gigasporaceae Cetraspora sp. and Dentiscutata sp. preferred undisturbed soil whereas Diversisporaceae, Glomeraceae and other Gigasporaceae were associated with recently restored soils. All AMF species were found in all plant species although Corymbiglomus corymbiforme was mainly associated with Echinophora spinosa. Our results might be of help for Mediterranean sand dune restoration.     

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.     

Highway verges as habitat providers for small mammals in agrosilvopastoral environments

The Mediterranean Basin has an important conservation value given its high biodiversity and high number of endemic species, which have co-existed with human traditional practices for centuries. However, northern areas as the Iberian Peninsula have experienced intensification in livestock production in recent past, with consequent reduction in habitat quality. In this study we assessed the importance of fenced highway verges as habitat for small mammals in Mediterranean agrosilvopastoral landscapes. More specifically, we compared small mammal abundance between highway verges and the adjacent two main land uses (“montado” and open areas); compared the vegetative structure among these land uses; and addressed how vegetation structure influences species occupancy. Thirty-six sites were sampled in agrosilvopastoral system areas in southern Portugal (sampling effort 8,840 trap-nights). A total of 351 individuals from target species were captured: 157 wood mice (Apodemus sylvaticus), 95 western Mediterranean mice (Mus spretus) and 99 greater white-toothed shrews (Crocidura russula). Capture–mark–recapture analyses were performed to estimate population size. Our data suggests that fenced highway verges promote better vegetative structure conditions which in turn favor a higher animal abundance therein. We suggest the adoption of management practices to increase the height and cover of herbaceous and shrub layers in road verges, together with creating grazing controlled areas in highway vicinity, particularly in “montado” patches, linked by vegetated linear features. This would increase habitat and refuge for a large numbers of species, including small mammals, and thus benefiting the trophic chain and the whole agrosilvopastoral system.     

Terrestrial Arthropods as Indicators of Ecological Restoration Success in Coastal Sage Scrub (California, U.S.A.)

Abstract Ecological restoration enjoys widespread use as a technique to mitigate for environmental damage. Success of a restoration project often is evaluated on the basis of plant cover only. Recovery of a native arthropod fauna is also important to achieve conservation goals. I sampled arthropod communities by pitfall trapping in undisturbed, disturbed, and restored coastal sage scrub habitats in southern California. I evaluated arthropod community composition, diversity, and abundance using summary statistics, cluster analysis, and detrended correspondence analysis (DCA) and investigated influence of vegetation on arthropod communities with multiple regression analysis. Arthropod diversity at undisturbed and disturbed sites was greater than at sites that were 5 and 15 years following restoration ( p < 0.05). Number of arthropod species was not significantly different among undisturbed, disturbed, and restored sites, and two restoration sites had significantly more individuals than other sites. Vegetation at disturbed and undisturbed sites differed significantly; older restorations did not differ significantly from undisturbed sites in diversity, percent cover, or structural complexity. In multiple regression models, arthropod species richness and diversity was negatively related to vegetation height but positively related to structural complexity at intermediate heights. Exotic arthropod species were negatively associated with overall arthropod diversity, with abundance of the earwig Forficula auricularia best predicting diversity at comparison (not restored) sites (r² = 0.29), and abundance of the spider Dysdera crocata and the ant Linepithema humile predicting diversity at all sites combined (r² = 0.48). Native scavengers were less abundant at restored sites than all other sites and, with a notable exception, native predators were less abundant as well. DCA of all species separated restored sites from all other sites on the first axis, which was highly correlated with arthropod diversity and exotic arthropod species abundance. Lower taxonomic levels showed similar but weaker patterns, with example families not discriminating between site histories. Vegetation characteristics did not differ significantly between the newly restored site and disturbed sites, or between mature restoration sites and undisturbed sites. In contrast, arthropod communities at all restored sites were, as a group, significantly different from both disturbed and undisturbed sites. As found in other studies of other restoration sites, arthropod communities are less diverse and have altered guild structure. If restoration is to be successful as compensatory mitigation, restoration success standards must be expanded to include arthropods.     

Roadside vegetation can provide valuable habitat for small, terrestrial fauna in South Australia

In some regions, extensive habitat clearance and fragmentation have largely restricted remnant vegetation to linear strips, often bordering roads and railway lines. Such areas may be important for the persistence of native wildlife but there is a paucity of research on their biodiversity value. This study in south-eastern South Australia compared the diversity and abundance of small, terrestrial animals in remnant vegetation, roadsides and farmland. Pitfall and Elliott trapping at 30 sites resulted in a total of 1,024 captures of 28 amphibian, reptile and mammal species, with 819 captures of six mammal species. Overall species diversity was highest in remnant sites and lowest in farm sites. Although low capture rates for reptiles and amphibians precluded statistical testing of individual species, many were caught in both remnant and roadside sites, but rarely at farm sites. Mammal captures consisted of four native (Cercartetus concinnus and C. lepidus, Pseudomys apodemoides and Rattus fuscipes) and two introduced (Mus musculus and Rattus rattus) species. Mus musculus was the most commonly caught species and was significantly more abundant in roadside than remnant vegetation. Abundance was negatively correlated with habitat quality and, at a finer scale, positively associated with percentage cover of exotic grasses. C. concinnus was also commonly captured; however, the absence of a difference in capture rates between remnant and roadside sites suggests that roadside vegetation provides important habitat. The abundance of C. concinnus was positively associated with percentage canopy cover. The current results highlight the conservation value of roadside vegetation and suggest that such areas should be both retained and appropriately managed.     

Wildlife-Habitat Restoration in an Urban Park in Southern California

Within an urban park in southern California, the relationship between the structure and floristics of vegetation and the distribution, abundance, and behavior of wildlife was studied in relatively undisturbed areas (San Luis Rey) and in contiguous areas (Guajome Park) in need of restoration. These data were used to develop recommendations for the enhancement of native animal species in the park. The abundance of amphibians and reptiles was highest in native upland scrub and willow (Salix)-riparian vegetation types, and lowest in dry, disturbed sites. Western fence lizards (Sceloporus occidentalis) were the most abundant reptile throughout both study areas. Overall, bullfrogs (Rana catesbiana), an exotic species, were the dominant amphibians; the native Pacific treefrog (Hyla regilla) was rare throughout. At both study areas, the small mammal community was dominated by western harvest mice (Reithrodontomys megalotis) and deer mice (Peromyscus maniculatus) and, to a lesser extent, by brush mice (P. boylii) and exotic house mice (Mus musculus). Negative correlations in abundance existed between house mice and harvest mice, and between house mice abundance and overall small mammal abundance. In riparian sites, cottonwood (Populus fremontii) and various height classes of willow were the dominant factors in the majority of bird abundance–habitat‘correlations and where foraging activities were concentrated. Recommendations for enhancing native animal species include reduction of marsh sedimentation, removal of feral species, and development of connections between the park and nearby natural areas. A corridor of native riparian vegetation (primarily cottonwood-willow) should be developed to replace the existing agricultural fields, thereby linking Guajome with the San Luis Rey River.     

Effects of commercial trawling activities in the diet of the flat fish Citharus linguatula (Osteichthyes: Pleuronectiformes) and the starfish Astropecten irregularis (Echinodermata: Asteroidea)

This study assesses the effects of commercial trawling on benthic fauna, by analysing differences in the population structure and diet of benthic organisms inhabiting fishing grounds. The study is focused on two epifaunal species collected from a fishing ground in the north-western Mediterranean, which included a portion of un-trawled seabed used as a reference of undisturbed community. The selected species were the flatfish Citharus linguatula, more abundant at the undisturbed site and previously characterised as a surface predator and vulnerable to trawling, and the starfish Astropecten irregularis, which dominated the epibenthic community and had been characterised as an opportunistic species with low vulnerability to trawling. Both species were selective feeders and ingested similar prey species at each of the two sites, although differences in the relative prey abundance found in the stomachs occurred between sites. A. irregularis at the fished site mainly ingested gastropods, whereas higher proportion of bivalves was ingested at the undisturbed site. C. linguatula diet mainly composed of crustaceans at both sites, but there was an increase in the ingestion of small fish at the fished site. Moreover, prey ingestion of these two species generally increased with fishing activity. Trawling appears to modify the diet of these two species in terms of relative abundance of ingested prey, nevertheless, increased opportunism due to trawling disturbance was not detected and the density of these predators over fishing grounds was more closely related to their vulnerability to trawling.     

Collembola as bioindicators of restoration in mined sand dunes of Northeastern Brazil

Opencast mining causes severe environmental impacts by removing the vegetation cover and depleting the fauna. Reforestation methods using native species and diverse pre- and post-disturbance approaches aim to recover the original richness and diversity of species found before the impact. Bioindicators are powerful tools to evaluate the restoration of the original environmental conditions in disturbed areas. We used species richness, endemism and diversity measurements of Collembola to compare successional stages in reforested sites of different ages compared with a control undisturbed area. Richness and abundance of Collembola were subjected to correlation analysis with age of plots and vegetational variables. Areas that were reforested for up to 16 years supported a much lower Collembola species richness than undisturbed areas. Both the age of reforestation plots and vegetation variables (number of trees, diameter of crowns, depth of leaf litter and tree species richness) were positively and significantly correlated to collembolan abundance and richness. The results showed that the diversity of the 16-year-old plot was significantly higher than that of younger areas, but significantly less diverse than that of the control area. Endemic species were more sensitive to disturbance than non-endemics. Thus, species richness and diversity of soil Collembola can be only partially restored with appropriate reforestation methods, and although it takes many years, to some extent even endemic species can be gradually restored. Nevertheless, the maintenance of undisturbed diversity reservoirs linked by ecological corridors to reforested plots is imperative, as only undisturbed areas can support most of the endemic species able to re-colonize reforested sites.     

Small mammal responses to moose supplementary winter feeding

Supplementary feeding of wild large herbivores is a widespread practice in North America and Europe. The presence of feeding stations may have ecological consequences through changes to animal distributions, patterns of herbivory and a net nutrient input into the ecosystem. In Fennoscandia, supplementary feeding of moose in winter (Alces alces) is increasing. Although it has been shown to affect bird communities, its effects on small mammal communities were unknown. Here, we studied the effects of moose supplementary feeding stations on plants and on abundance, reproduction, and biomass of small mammals in years with low and high vole abundance. We sampled small mammals with snap traps and conducted surveys of the field layer vegetation, at varying distances from moose supplemental feeding stations. Due to the vegetation changes induced by feeding stations, abundance of common shrews (Sorex araneus) and Microtus voles were positively affected by long-term moose winter feeding, while bank voles (Myodes glareolus) were not affected. Moose feeding stations did not affect reproduction, individual body mass, or the total biomass of small mammals. Moose winter-feeding stations have impacts on nontarget species, providing islands of preferred grass and forb habitat for Microtus spp. and common shrews, allowing them to penetrate into a matrix of less preferred forest habitat.     

The small mammal community of a coastal site of south-west Mauritania

The small mammal community of a coastal site of south-western Mauritania was monitored using live trapping, owl pellet analysis and nocturnal visual censuses. Ten species of rodents and two shrews were recorded. Gerbillid rodents ( Gerbillus nanus, G. gerbillus, G. tarabuli, G. nigeriae and Taterillus arenarius ) were the most prevalent in traps, whereas a relatively large proportion of owl pellets were made up of a murid rodent, Mastomys huberti . The presence of two species of murids ( M. huberti and Arvicanthis niloticus ) in this presaharian environment is made possible by the presence of small patches of green vegetation associated with localized fresh water inputs. The contradiction of results from the sampling methods indicate potential biases in the determination of community composition and relative species abundance. Results are also discussed in estimating the potential role of predation and competition in this small mammal community.     

Diversity of rodents and shrews along an elevational gradient in Bwindi Impenetrable National Park, south-western Uganda

Small mammal species diversity in the major vegetation zones of Bwindi Impenetrable National Park is discussed in relation to altitude. Species richness of the small mammals was found to decrease with an increase in altitude. The main factors accounting for the observed diversity are the wide altitudinal variation and a complex array of vegetation types. Sixty‐seven species of rodents and shrews were found to exist in the Park; 47 of which were rodents and 20 shrews. Of these, 26 species are new to the Bwindi Park list. Three species have probably not been described before. The study found 10 species of small mammals to be Albertine Rift endemics. Three genera are recorded in Uganda for the first time: Rwenzorisorex, Suncus and Paracrocidura. Five species are new records for East Africa. These are Crocidura stenocephala, Lophuromys rahmi, L. medicaudatus, Paracrocidura maxima and Hylomyscus aeta. Because of the high endemism of plants, butterflies, birds and now of small mammal species, Bwindi forest is a unique biodiversity hotspot and is among the highest conservation priorities in the Albertine Rift.     

Soil zoology I: arthropod communities in open landscapes of former brown coal mining areas

In different habitat types of the former coal mining area of Lower Lusatia, distribution and abundance of species of various arthropod groups was studied as to the colonization dynamics and the formation of community patterns. Heteroptera, Auchenorrhyncha, different groups of Coleoptera, Araneida, and Orthoptera were included in the study. In total, about 850 species were captured by pitfall trapping and sweepnet sampling. A detailed analysis of species–environment-relations was performed by means of gradient and eigenvector analysis (DCA, CCA). It is shown that colonization of bare sand habitats, pioneer vegetation with ruderal herbs, short grass prairie with Corynephorus and xerophytic herbs, tall grass prairie with Calamagrostis, and shrubs takes place rather quickly. In all the analysed habitats an adequate degree of the colonization was attained by the studied groups. Both the formation of patterns of species assemblages and population dynamics in upper layers of vegetation mainly depend on the patterns of plant communities and vegetation architecture. In lower layers micro-climatic conditions as well as abiotic soil parameters were shown to be of special importance. Differences of community patterns between predators and mainly phytophagous arthropod groups were discussed.     

Disturbance effects from fire and mining produce different lizard communities in eastern Australian forests

The lizard fauna of sand‐mined dunes of the central coast of New South Wales, Australia has been shown to be dominated by Ctenotus robustus and Ctenotus taeniolatus (Scincidae), with relative abundance changing with time since mining. However, there is little published information on how this lizard fauna compares to that of the undisturbed open forest that previously grew on these sites. Here, existing data are added to in order to produce a longer chronosequence of times since sand‐mining (4, 8, 14 and 20 years) than has been examined previously. The new data are compared to those from unmined forests. Ctenotus robustus and C. taeniolatus dominated lizard captures on mined areas, with peak abundances at 8 and 14 years, respectively. Lampropholis guichenoti (Scincidae) was at low abundance until 20 years post‐mining and L. delicata was present only at 20 years post‐mining. Unmined forest burned 4, 8 or 14 years ago had a significantly different lizard community from that of sand‐mined areas. Ctenotus robustus and C. taeniolatus were absent from unmined forest at all post‐fire periods. Lampropholis guichenoti and Lampropholis delicata were numerically dominant in forest, with increasing abundance of L. guichenoti with time since fire. Thus the composition of the lizard community on these coastal dunes is not solely determined by time since disturbance per se. Comparisons of sites on the basis of accumulated leaf litter showed a significant relationship between Lampropholis abundance and litter density. On sand‐mined sites and forested sites with similar leaf litter densities, the abundances of L. guichenoti were similar. As Ctenotus were absent from unmined forest, we could not compare their distribution in unmined and mined areas. However, negative correlations of Ctenotus abundance with canopy cover and understorey vegetation density offer a possible explanation for the absence of these species from forest.     

Assessing the disturbance impact on vegetation and lizard communities of fluoride pollution interacting with fire and mining in eastern Australia

The effects of atmospheric fluoride pollution on the lizard fauna of the open forest of coastal dunes in New South Wales, Australia were examined. Lizards were pitfall-trapped at sites with background fluoride levels (< 0.25 μmol F.g^–1), or subject to low (1.85–3.4 μmol F.g^–1) or high (8.00–13.2 μmol F.g^–1) levels of fluoride pollution. Sites had been disturbed by fire or mineral sand-mining 4 or 8 years prior to the study. Fluoride pollution resulted in significant changes to canopy cover, understorey vegetation density and ground cover. Where fluoride levels were low in unmined forest, there was significantly higher species richness, total lizard abundance and abundance of the most common species, Lampropholis guichenoti and Lampropholis delicata (Scincidae), compared with areas of high or background fluoride levels. Both the present and previous studies show that fluoride pollution is significantly correlated with increased abundance of the most common lizard species in sand-mined areas, Ctenotus robustus, Ctenotus taeniolatus (Scincidae) and Amphibolurus muricatus (Agamidae). A discriminant function model of background-fluoride mined sites was used to predict lizard abundances based on vegetation density, leaf litter density and soil hardness. The model was verified by using it to predict similarities between background-fluoride sites and fluoride-affected sites. The sites within each predicted group were more similar in lizard species composition than when grouping of sites was done by time since mining or fire. With this analysis, a close relationship between vegetation variables and the lizard fauna, irrespective of the type of disturbance or time since disturbance, is demonstrated. Discriminant function analysis suggested that Ctenotus would be unlikely to use unmined forest sites that had been burned within 12 months previously. Thus it seems unlikely that the original open forest of these coastal dunes would have supported populations of either C. robustus or C. taeniolatus. In conclusion, the original source of Ctenotus that colonized sand-mined areas is more likely to have been the relatively small areas of heath vegetation in the area. Therefore, sand-mining and atmospheric fluoride pollution result in landscape-scale changes to the relative abundance of lizard species, with forest species becoming less common and lizard species from open areas becoming more common.     

Community and population dynamics of serpentine grassland annuals in relation to gopher disturbance

Summary This study examines the effects of soil disturbance by gophers on patterns of species abundance in an annual grassland community on serpentine soil. We assessed production, dispersal and storage of seed, germination, survivorship and growth of the most abundant species in undisturbed vegetation and on gopher mounds. Fewer seeds of the dominant species were dispersed onto gopher mounds due to the limited movement of seeds from within the closed vegetation. Species with taller flowering stalks were more likely to colonise gopher mounds. The timing of gopher disturbance in relation to the timing of seed fall determined which species could colonise mounds. Lower numbers of seeds falling onto gopher mounds resulted in lower seedling densities of several species compared with undisturbed areas. Survivorship of the commonest species differed between undisturbed areas and gopher mounds formed at different times of year. This resulted in characteristic spectra of species abundance on the different microhabitats, giving rise to distinct spatial patterning in the community. Plants growing on gopher mounds were generally larger and produced more seed than plants in undisturbed vegetation. We suggest that continued gopher disturbance is a factor allowing several species, including perennial grasses, to persist in this community.     

Long-term responses in population dynamics and diversity of small mammals in riparian and upland habitats within an agricultural landscape

Riparian zones in agricultural landscapes provide linear non-crop habitats for a variety of plant and mammal species, and hence are an important component of biodiversity. To date, variable responses of abundance, species richness, and species diversity of small mammals have been recorded in riparian and upland habitats. To address this variability, we provide a detailed analysis of seasonal changes in abundance and diversity of terrestrial small-mammal communities over a 7-year period within an agricultural landscape in south-central British Columbia, Canada. We tested the hypotheses (H) that abundance, species richness, and species diversity of communities of small mammals (H₁), and demographic parameters of reproduction, recruitment, and survival of the major species: deer mouse (Peromyscus maniculatus) and montane vole (Microtus montanus) (H₂), would be higher in riparian than upland habitats. Mean total abundance of small mammals was higher in summer and winter, and species richness higher in summer, in riparian than hedgerow habitats. Winter population data supported the total and species abundance patterns for small mammals, but species richness was similar, and diversity lower, in riparian than hedgerow sites during winter periods. Deer mice were the dominant species in terms of abundance and reproductive output for pregnancies and recruitment, but not survival, in riparian sites. Montane voles were similar in abundance and demographic parameters in the two habitats. House mice (Mus musculus) preferred hedgerows and wandering shrews (Sorex vagrans) riparian sites. Demographic parameters for deer mice and montane voles indicated that both riparian and hedgerow sites were “source” rather than “sink” habitats, and likely contribute to maintenance of mammal diversity in agricultural landscapes.     

On the structure of rodent communities in tropical forests of southern Vietnam

The abundance, species diversity, and spatial distribution of small mammals were studied in two localities in southern Vietnam: the Cat Tien National Park and the Binh Chau Nature Reserve. Rodents were trapped on the ground and in the tropical forest canopy (2–12 m above the ground), marked, and released on the spot. Species diversity of small mammals in undisturbed tropical forest (9 species) was higher than in disturbed tropical forest (14 species). The rat Maxomys surifer and the squirrel Callosciurus flavimanus were dominant. In undisturbed forest, the frequencies of rodent occurrence on the ground and in the canopy were of the same order; in disturbed forest, rodents occurred in the canopy an order of magnitude less frequently than on the ground.