Blood parasites, total plasma protein and packed cell volume of small wild mammals trapped in three mountain ranges of the Atlantic Forest in Southeastern Brazil.

A study of blood parasites in small wild non-flying mammals was undertaken in three areas of the Atlantic Forest in Southeastern Brazil: Serra de Itatiaia, RJ, Serra da Bocaina, SP and Serra da Fartura, SP, from June 1999 to May 2001. A total of 450 animals (15 species) were captured in traps and it was observed in 15.5% of the blood smears the presence of Haemobartonella sp. and Babesia sp. in red blood cells. There was no statistically significant difference between parasited and non-parasited specimens regarding total plasma protein, packed cell volume and body weight, which strongly suggests that these specimens might be parasite reservoirs.     

Post-fire succession of small mammals in the Cerrado of central Brazil

In the Cerrado savannas from Brazil fire events are common and strongly influence the vegetation structure and, consequently, the associated small mammals. In this paper, we investigate changes in the structure of small mammal communities related to sites of different post-fire ages. Mammals were captured in similar Cerrado sites that differed in time since the last burn (1 to 26 yr). We sampled six sites in the wet season of 1997 (phase 1) and, three years later, six sites in the wet and dry seasons (phase 2). Six rodent species and four marsupials were captured. Community composition changed drastically as a function of time since fire. The diversity and abundance of small mammals reached maximum values in the early successional stages. The rodent Calomys tener was present only in early seral stages. The rodent Bolomys lasiurus was more frequent in mid-successional stages and decreased in later seral stages, and the rodent Oryzomys subflavus occupied all successional stages. The marsupial Gracilinanus agilis was dominant in the area that did not burn for at least 23 yr. Changes in composition of the community of small mammals were more accelerated in early successional stages, when there are more drastic vegetational changes. The ability of small mammals to cope with Cerrado fires and the great dissimilarity among post-burning seral stages suggest that a mosaic of areas representing different post-fire seral stages could increase the regional diversity of this group.     

Small mammals in high altitude phytophysiognomies in southeastern Brazil: are heterogeneous habitats more diverse?

The Chapada das Perdizes is considered a region of high biodiversity, but there are few studies that describe the small mammals in the region, mainly in higher portions of the area. The primary objective of this study was to estimate the richness and abundance of terrestrial small mammals within three different vegetation types in the high altitude region of southern Minas Gerais and to evaluate the relationship between the community composition of terrestrial small mammals and the heterogeneity of phytophysiognomies. Pitfall and cage trap grids were arranged in natural field, semi-deciduous and cloud forests. A total of 26 species was recorded. The compositions of the three phytophysiognomies were significantly different. The expansive study area is located in a region of tension between the Cerrado and Atlantic Forests and should be preserved due to high diversity and ecological importance.     

Response of wild mammals to seasonal shrinking-and-expansion of habitats due to flooding regime of the Pantanal, Brazil.

The Pantanal is a large savanna wetland (138,183 km2 in Brazil), important for its wildlife, fed by tributaries of the upper Paraguay River, center of South America (Brazil, touching Bolivia and Paraguay). Uplands are plateaus (250-1,200 m high, 215,000 km2 in Brazil) and flatland is the Pantanal (80-150 m high, 147,574 km2 in Brazil). Rivers are slow moving when they meet the flatland (slope 0.3-0.5 m/km east-west; 0.03-0.15 m/km north-south), periodically overflowing their banks, creating a complex seasonal habitat range. Recurrent shallow flooding occupies 80% of the Pantanal; during the dry season flooded areas dry up. Fluctuating water levels, nutrients and wildlife form a dynamic ecosystem. A flooding regime forms distinct sub-regions within the Pantanal. A mammal survey was carried out in the sub-region of the Rio Negro from April, 2003 through March, 2004 to study the diversity and abundance of terrestrial mammals during the dry and flooding seasons. A total of 36 species were observed in the field. The capybara Hydrochaeris hydrochaeris was the most frequent species, followed by the crab-eating-fox Cerdocyon thous and the marsh deer Blastocerus dichotomus. The highest abundance of species was observed during the dry season (August and September), when there is a considerable expansion of terrestrial habitats, mainly seasonally flooded grassland. Animal abundance (in terms of observed individual frequencies) varied during the dry and wet seasons and the seasonally flooded grassland was the most utilized habitat by mammals in the dry season.     

Prevalence and lineage diversity of avian haemosporidians from three distinct cerrado habitats in Brazil

Habitat alteration can disrupt host-parasite interactions and lead to the emergence of new diseases in wild populations. The cerrado habitat of Brazil is being fragmented and degraded rapidly by agriculture and urbanization. We screened 676 wild birds from three habitats (intact cerrado, disturbed cerrado and transition area Amazonian rainforest-cerrado) for the presence of haemosporidian parasites (Plasmodium and Haemoproteus) to determine whether different habitats were associated with differences in the prevalence and diversity of infectious diseases in natural populations. Twenty one mitochondrial lineages, including 11 from Plasmodium and 10 from Haemoproteus were identified. Neither prevalence nor diversity of infections by Plasmodium spp. or Haemoproteus spp. differed significantly among the three habitats. However, 15 of the parasite lineages had not been previously described and might be restricted to these habitats or to the region. Six haemosporidian lineages previously known from other regions, particularly the Caribbean Basin, comprised 50-80% of the infections in each of the samples, indicating a regional relationship between parasite distribution and abundance.     

Length–weight relationships for 25 fish species from three coastal lagoons in Southeastern Brazil

This work analyzes the relationship between length and weight for 25 fish species belonging to 15 families in three mixohaline/hypersaline coastal lagoons in Southeastern Brazil. The study presents the first estimation of L–WRs for six species (Anchoa tricolor, Brevoortia aurea, Jenynsia multidentata, Ctenogobius boleosoma, Microgobius meeki and Bathygobius soporator) and maximum lengths for four species (Atherinella brasiliensis, Jenynsia multidentata, Poecilia vivipara and Microgobius meeki) that are greater than previously recorded.     

Pollination Biology of Piperaceae Species in Southeastern Brazil

Phenology, floral biology and breeding system are describedfor 14 Piperaceae species at two sites covered by semi-deciduousforest in southeastern Brazil. Flowering occurred continuouslythroughout the year, with a peak during the windy months. Allspecies had minute odorous and nectarless flowers visited byinsects; five of them showed a substantial degree of self-compatibility,and one was andromonoecious. Seven species were wind pollinated,and three were exclusively pollinated by insects. Flower visitorswere mainly hoverflies and bees. Copyright 2000 Annals of BotanyCompany Piper spp., Ottonia spp., Pothomorphe umbellata, pepper family, phenology, floral biology, breeding system, ambophily, semi-deciduous forest     

A simple mechanical device for recording the diel activity pattern of small burrowing mammals in their natural habitats

A mechanical device for monitoring the diel activity pattern of small burrowing mammals under natural conditions is described. The device has been used to estimate the time spent by the Indian gerbil, Tatera indica indica Hardwicke in foraging above ground and in an underground nest which is a part of the device. Activity patterns recorded with this device have confirmed observations that Tatera i, indica is nocturnal. The average time spent by this rodent outside the nest during an eight day study period was 318 min/24h. These rodents are generally active between 1900–0300 hrs, apparently with two peaks of activity, one between 2100–2200 hrs and the other between 0100–0200 hrs.     

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.     

横断山区三种小型哺乳动物代谢特征的研究进展

代谢率是生理生态学中的重要指标,能反映不同物种和个体之间的能量消耗水平,在动物适应环境的过程中具有重要的意义,各种不同的物理和生物因素都可能影响到动物的代谢特征。本文综述了体重和温度对横断山区小型哺乳动物中缅树鼩、大绒鼠和高山姬鼠代谢率的影响,比较了3种小型哺乳动物与其它地区小型哺乳动物的异同点,并给出了横断山区小型哺乳动物特殊的一些代谢特征。最后,通过比较代谢产热特征探讨了中缅树鼩的起源问题。     

Ixodid ticks (Parasitiformes: Ixodidae) from small mammals in reforesting boreal habitats of the northern European Russia

Abundance of 2 ixodid tick species, Ixodes (Exopalpiger) trianguliceps Birula, 1895 and Ixodes (Ixodes) persulcatus Schulze, 1930 was studied during 6 years, in 1998–2001 and 2003–2004, at a research station in Gomselga Village (central Karelia, Kondopoga District, 62°04′N, 33°55′E). New data on host species composition and ixodid tick abundance were obtained from 4 forest plots at different stages of reforestation (secondary succession) following felling that occurred 7–14, 12–19, 25–32, and 80–87 years ago. Individuals of I. persulcatus predominated and constituted 73% of the total ticks collected. The occurrence rates of different developmental stages were shown to fluctuate in the course of reforestation both in I. trianguliceps (larvae, 2.8–5.3; nymphs, 1.5–2.2; adults, 0–0.09) and in I. persulcatus (larvae, 4.3–10.6; nymphs, 0.6–4.2).     

Trypanosomes of small mammals in Iran

Trypanosomes in the subgenera Herpetosoma, Schizotrypanom and Megatrypanum were found in 31 small mammals representing nine species of the orders Rodentia, Insectivora and Chiroptera in Iran.     

The ecology of three communities of small mammals at different altitudes in Malawi, Central Africa

This study compares the results of three studies and assesses the effects of seasonal changes in the environment on populations of small mammals at three altitudes in Malawi (Zomba Plateau [1900 m], Liwonde National Park [550 m] and Lengwe National Park [100 m]). Zomba Plateau had a higher annual rainfall (mean 2244 mm), longer wet season, shorter dry season, cooler temperatures and smaller water deficit than either Liwonde NP or Lengwe NP (which had similar climates). Maximum grass biomass (and fluctuation index) was 814 g/m² (1.7) on Zomba Plateau, 1066 g/m² (2.7) at Liwonde, and 854 g/m² (30.5) at Lengwe. Sixteen species of rodents were recorded, 7–9 at each study area; the species on Zomba Plateau did not occur at the lower altitudes, and the lower altitude species did not occur on Zomba Plateau. Percentage Similarity and Coefficients of Community showed that there was considerable similarity between Liwonde and Lengwe, but no similarity between either of them and Zomba Plateau. Mean population densities of small rodents (range, fluctuation index) were 23/ha (15–35, 2.3) on Zomba Plateau, 12.6 (2.7–19.1, 7.1) at Liwonde, and 14.5 (0.9–30.9, 33.9) at Lengwe. Stability of the environment tends to confer stability in demographic characteristics. Reproduction was mainly confined to the wet season (December to April) at all altitudes. Comparison of the proportion of new individuals each month, and the duration of residence by individuals, suggests that turnover of the population was slowest on Zomba Plateau and fastest at Lengwe. There was no evidence for reduced litter size, reduced opportunity for reproduction, or increased age to maturity at the highest altitude compared with the lower altitudes as has been recorded in temperate environments.