The hypoxia adaptation of small mammals to plateau and underground burrow conditions

Oxygen is one of the important substances for the survival of most life systems on the earth,and plateau and underground burrow systems are two typical hypoxic environments.Small mammals living in hypoxic environments have evolved different adaptation strategies,which include increased oxygen delivery,metabolic regulation of physiological responses and other physiological responses that change tissue oxygen utilization.Multiomics predictions have also shown that these animals have evolved different adaptations to extreme environments.In particular,vascular endothelial growth factor(VEGF)and erythropoietin(EPO),which have specific functions in the control of O_(2) delivery,have evolved adaptively in small mammals in hypoxic environments.Naked mole-rats and blind mole-rats are typical hypoxic model animals as they have some resistance to cancer.This review primarily summarizes the main living environment of hypoxia tolerant small mammals,as well as the changes of phenotype,physiochemical characteristics and gene expression mode of their long-term living in hypoxia environment.

Diversity and habitat association of small mammals in Aridtsy forest, Awi Zone, Ethiopia

Here, we conducted a survey to examine the diversity, distribution and habitat association of small mammals from August 2011 to February 2012 incorporating both wet and dry seasons in Aridtsy forest, Awi Zone, Ethiopia. Using Sherman live traps and snap traps in four randomly selected trapping grids, namely, natural forest, bushland, grassland and farmland, a total of 468 individuals comprising eight species of small mammals（live traps） and 89 rodents of six species（snap traps） were trapped in 2352 and 1200 trap nights, respectively. The trapped small mammals included seven rodents and one insectivore： Lophuromys flavopuntatus（30.6%）, Arvicanthis dembeensis（25.8%）, Stenocephalemys albipes（20%）, Mastomys natalensis（11.6%）, Pelomys harringtoni（6.4%）, Acomys cahirinus（4.3%）, Lemniscomys zebra（0.2%） and the greater red musk shrew（Crocidura flavescens, 1.1%）. Analysis showed statistically significant variations in the abundance and habitat preferences of small mammals between habitats during wet and dry seasons.

Bartonella species in small mammals and their potential vectors in Asia

In this article,authors review the current knowledge of Bartonella infection in small mammals including rodents,insectivores,bats and exotic small mammal pets and their vectors in Asia.Species of Bartonella are Gram-negative intracellular bacteria that infect erythrocytes of various mammalian and non-mammalian animals and mainly transmitted by blood sucking arthropod vectors.The genus Bartonella includes several species of important human diseases with severe clinical signs.Several new Bartonella species were isolated from rodents and other small mammals,and from human patients in Asia.Bartonella species are identified using standard polymerase chain reaction amplification and a sequencing targeting two housekeeping genes(glt.A and rpoB) and the internal transcribed spacer fragment.Authors also discuss the implications in term of potential emerging zoonotic diseases.

Influence of Human Disturbance to the Small Mammal Communities in the Forests

Small mammals have been proposed playing an important role in the energy flow and regeneration of forest ecosystems. We compared species richness, diversity (H’) of small mammal communities and abundance of six dominant species of small mammals in disturbed and protected forests (four age classes: 6 - 10, 11 - 15, 16 - 20 and 31 - 40 years old) in China. We also investigated the structural variables (such as species richness, cover rate and abundance of shrubs and grasses) in the bottom layer, which considered to be important for small mammals and might be altered by human disturbance. The relationships between small mammals and these structural variables were examined to determine the potential effects of human disturbance on the small mammals in the restored forests. Our results indicated that the structure and composition of the vegetation in the bottom layer were simplified by human disturbance, while the abundance and cover rate of grasses were significantly increased. Although no significant differences were observed in species richness of small mammals between the protected and disturbed forests at the same age, the diversity index of small mammals in the protected forests was always significantly higher than in the disturbed forests. Regression showed that the species richness and diversity of small mammals increased with the species richness of shrubs, and was negatively correlated to the cover rate of grasses in the bottom layer. Human disturbance increased the total abundance of small mammals, and the increased cover rate of grasses in the bottom layer was beneficial to the abundance of small mammals. Obvious succession of small mammal communities occurred as the protected forest aged. In the protected forests, small ground-dwelling mammals (A. chevrieri, E. miletus and M. pahari) were the dominant species in the younger forests. Other mammals (T. belangeri, D. pernyi and C. erythraeus) gradually became the dominant species as the protected forests aged. However, in the disturbed forests, the smaller ground-dwelling mammals (T. belangeri, D. pernyi and C. erythraeus) were always the dominant species at all ages of the disturbed forests. Regression indicated that the cover rate of grasses in the bottom layer was beneficial to the three smaller body size and ground-dwelling small mammal species, while the shrubs were beneficial to the three bigger body size mammal species.

Small Mammal Habitat Use within Restored Riparian Habitats Adjacent to Channelized Streams in Mississippi

Riparian zones of channelized agricultural streams in northwestern Mississippi typically consist of narrow vegetative corridors low in habitat diversity and lacking riparian wetlands. Land clearing practices and stream channelization have led to the development of gully erosion and further fragmentation of these degraded riparian zones. Currently, installation of a gully erosion control structure (drop pipe) at the riparian zone-agricultural field interface leads to the incidental establishment of four riparian habitat types that differ in habitat area, vegetative structure, and pool size. Small mammals were sampled within four sites of each habitat type from June 1994 to July 1995. Small mammal diversity, abundance, and hispid cotton rat (Sigmodon hispidus) weight were the least within smallest Type I habitats with the least vegetative structural diversity and were the greatest within the larger Type II, III, or IV habitats having greater vegetative structural diversity and pool size. Small mammal diversity and abundance were the least in the summer 1994, increased in the fall 1994, and then declined later in our study. Hispid cotton rat abundance was the least in summer 1994, winter 1994, and spring 1995 and was the greatest in fall 1994 and summer 1995. Our results suggest that modifying the drop pipe installation design to facilitate the development of larger riparian habitats with greater vegetative structural diversity will provide the greatest benefits for small mammals.

Small mammal community composition impacts bank vole (Clethrionomys glareolus) population dynamics and associated seroprevalence of Puumala orthohantavirus

Rodents are important reservoirs for zoonotic pathogens that cause diseases in humans.Biodiversity is hypoth-esized to be closely related to pathogen prevalence through multiple direct and indirect pathways.For example,the presence of non-host species can reduce contact rates of the main reservoir host and thus reduce the risk of transmission(“dilution effect”).In addition,an overlap in ecological niches between two species could lead to increased interspecific competition,potentially limiting host densities and reducing density-dependent pathogen transmission processes.In this study,we investigated the relative impact of population-level regulation of direct and indirect drivers of the prevalence of Puumala orthohantavirus(PUUV)in bank voles(Clethrionomys glareolus)during years with high abundance.We compiled data on small mammal community composition from four regions in Germany between 2010 and 2013.Structural equation modeling revealed a strong seasonality in PUUV control mechanisms in bank voles.The abundance of shrews tended to have a negative relationship with host abundance,and host abundance positively influenced PUUV seroprevalence,while at the same time increasing the abundance of competing non-hosts like the wood mouse(Apodemus sylvaticus)and the yellow-neckedfield mouse(Apodemusflavicollis)were associated with reduced PUUV seroprevalence in the host.These results indicate that for PUUV in bank voles,dilution is associated with increased interspecific competition.Anthropogenic pressures leading to the decline of Apodemus spp.in a specific habitat could lead to the amplification of mechanisms promoting PUUV transmission within the host populations.

Alpine grassland degradation intensifies the burrowing behavior of small mammals:evidence for a negative feedback loop

Globally,grassland degradation is an acute ecological problem.In alpine grassland on the Tibetan Plateau,increased densities of various small mammals in degraded grassland are assumed to intensify the degradation process and these mammals are subject to lethal control.However,whether the negative impact of small mammals is solely a result of population size or also a result of activity and behavior has not been tested.In this study,we use plateau pika as a model to compare population size,core area of colony,and the number of burrow entrances and latrines between lightly and severely degraded grassland.We test whether the alleged contribution of pika to grassland degradation is a result of increased population size or increased burrowing activities of individuals in response to lower food abundance.We found that grassland degradation resulted in lower plant species richness,plant height,and biomass.Furthermore,the overall population size of pika was not significantly affected by location in lightly and severely degraded grassland.However,pika core areas in severely grassland degradation were significantly larger and had significantly higher densities of burrows and latrines.Our study provides convincing evidence that habitat-induced changes in the behavior of small,burrowing mammals,such as pika,can exacerbate grassland degradation.This finding has significant implications for managing small mammals and restoring degraded grassland ecosystems.

Distribution of gamasid mites on small mammals in Yunnan Province, China

An investigation of gamasid mites on the body surface of small mammals was carried out in Yunnan Province of China from 1990 to 2004. The small mammal hosts were captured from 25 counties which represent five geographical subregions, namely Middle Subregion of Hengduan Mountains, Southern Subregion of Hengduan Mountains, Eastern Plateau Subregion of Yunnan, Western Plateau Subregion of Yunnan and Southern Moun- tainous Subregion of Yunnan. The captured 10 803 small mammal hosts belong to nine families, 29 genera and 52 species in four orders （Rodentia, Insectivora, Scandentia and Lagomorpha）. A total of 68 571 gamasid mites were collected from the body surface of the captured small mammal hosts and all the gamasid mites were identified to 10 families, 33 genera and 112 species. This paper lists all the mite species, together with their taxonomic position （genera and families） and their corresponding hosts. Much more mite species were found in the Middle Subregion of Hengduan Mountains than in other geographical subregions. The total individuals of mites and small mammals in the Middle Subregion of Hengduan Mountains are also the most plentiful in the five geographical subregions. Three dominant mite species and three dominant small mammal hosts were determined as the dominant species in the investigated areas of Yunnan Province. The dominant hosts are Rattus flavipectus （which accounts for 34.85% of the total individuals）, Apodemus chevrieri （13.43%） and Rattus norvegicus （10.40%） while the dominant gamasid mite species are Laelaps nuttalli （Hirst, 1915） （27.84%）, Laelaps echidninus （Berlese, 1887） （18.38%） and Laelaps guizhouensis （Gu et Wang, 1981） （14.79%）. The results showed the high species diversity of gamasid mites in Yunnan Province and the uneven distribution feature in different subregions.

Small mammal community succession on the beach of Dongting Lake,China after the Three Gorges Project

Although the Three Gorges Project(TGP)may have affected the population structure and distribution of plant and animal communities,few studies have analyzed the effect of this project on small mammal communities.Therefore,the present paper compares the small mammal communities inhabiting the beaches of Dongting Lake using field investigations spanning a 20-year period,both before and after the TGP was implemented.Snap traps were used throughout the census.The results indicate that the TGP caused major changes to the structure of the small mammal community at a lake downstream of the dam.First,species abundance on the beaches in­creased after the project commenced.The striped field mouse(Apodemus agrarius)and the Norway rat(Rat­tus norvegicus),which rarely inhabited the beach before the TGP,became abundant(with marked population growth)once water was impounded by the Three Gorges Reservoir.Second,dominant species concentration in­dices exhibited a stepwise decline,indicating that the community structure changed from a single dominant spe­cies to a more diverse species mix after TGP implementation.Third,the regulation of water discharge release by the TGP might have caused an increase in the species diversity of the animal community on the beaches.A sig­nificant difference in diversity indices was obtained before and after the TGP operation.Similarity indices also indicate a gradual increase in species numbers.Hence,a long-term project should be established to monitor the population fluctuations of the Yangtze vole(Microtus fortis),the striped field mouse and the Norway rat to safe­guard against population outbreaks(similar to the Yangtze vole outbreak in 2007),which could cause crop dam­age to adjacent farmland,in addition to documenting the succession process of the small mammal community inhabiting the beaches of Dongting Lake.

Integrating small mammal community variables into aircraft–wildlife collision management plans at Namibian airports

Understanding ecosystems within and around airports can help to determine the causes and possible mitigation measures for collisions between aircraft and wildlife.Small mammal communities are an important component of the semi-arid savanna ecosystems of Namibia,its productivity and its ecosystem integrity.They are also a major direct attractant for raptors at airports.The present study compared the abundance and diversity of small mammals between Namibia’s 2 main airport properties(Hosea Kutako International Airport and Eros Airport),and among areas of land used for various purposes surrounding the airports.A total of 2150 small mammals(3 orders,11 species)were captured over 4 trapping seasons.Small mammal abundance was significantly higher at the end of the growing season than during the non-growing season.The grass mowing regimen in current management plans at the airports resulted in a significant reduction of small mammal abundance at Hosea Kutako during the non-growing season only,thus indicating that annual mowing is effective but insufficient to reduce the overall abundance of mammal prey species for raptors.Small mammal numbers were significantly higher at Hosea Kutako Airport compared to the cattle and game farming land surrounding the airport,while no differences in small mammal densities or diversity were found for areas with different land uses at and surrounding Eros.The study suggests that the fence around Hosea Kutako provides a refuge for small mammals,resulting in higher densities.It also indicates that different surrounding land use practices result in altered ecosystem function and productivity,an important consideration when identifying wildlife attractants at airports.

Revealing the real-time diversity and abundance of small mammals by using an Intelligent Animal Monitoring System(IAMS)

It is challenging to reveal the real-time spatio-temporal change of diversity and abundance of animals in natural systems by using traditional methods.The rapid advancement of new technologies such as the Internet of Things,artificial intelligence,and big-data processing,provide opportunities for developing novel technologies for moni-toring biodiversity and population abundance of animals with high efficacy and accuracy.In this study,by using a recently developed Intelligent Animal Monitoring System,named“Vector Intelligent Monitoring System(VIMS)”,we investigated the real-time diversity and abundance of small mammals in the Banruosi forest,Dujiangyan region,southwest China.To make a comparison of the VIMS with traditional methods,we also surveyed the diversity and abundance of small mammals using wired live traps.Compared to live traps,the VIMS has several advantages such as automatic data collection,intelligent identification of species,data visualization,whole-day and all-weather op-eration,little disturbance to animals,real-time monitoring,and is capable of revealing more small mammal species.However,the VIMS also has several disadvantages over live traps such as lower trapping efficiency and being more expensive than live traps.Our results suggest that the VIMS can be a complementary method to traditional ones in monitoring the real-time spatio-temporal change of diversity and abundance of small mammals(especially rare species).In addition,the VIMS is useful in monitoring other small animals like small carnivores,birds,amphibians,and reptiles.

Ethyl-iophenoxic acid as a quantitative bait marker for small mammals

Bait markers are indispensable for ecological research but in small mammals,most markers are invasive,expensive and do not enable quantitative analyses of consumption.Ethyl-iophenoxic acid(Et-IPA)is a non-toxic,quantitative bait marker,which has been used for studying bait uptake in several carnivores and ungulates.We developed a bait with Et-IPA,assessed its palatability to common voles(Microtus arvalis),and determined the dose-residue-relation for this important agricultural pest rodent species.Et-IPA concentrations of 40 to 1280μg Et-IPA per g bait were applied to wheat using sunflower oil or polyethylene glycol 300 as potential carriers.In a laboratory study,common voles were offered the bait and blood samples were collected 1,7,and 14 days after consumption.The samples were analyzed with LC-ESI-MS/MS for blood residues of Et-IPA.Sunflower-oil was the most suitable bait carrier.Et-IPA seemed to be palatable to common voles at all test concentrations.Dose-dependent residues could be detected in blood samples in a dose-dependent manner and up to 14 days after uptake enabling generation of a calibration curve of the dose-residue relationship.Et-IPA was present in common vole blood for at least 14 days,but there was dissipation by 33–37%depending on dose.Et-IPA meets many criteria for an“ideal”quantitative bait marker for use in futurefield studies on common voles and possibly other small mammal species.

Long-term changes in a small mammal community in a temperate zone meadow subject to seasonal floods and habitat transformation

We tested small mammal(SM)community response to the influence of seasonal floods and habitat transformation in a temporal zone meadow(west Lithuania).The habitat transitioned from a natural flooded meadow in 2008–2012 to a mowed and pastured area in 2020.SM were trapped in late summer to autumn using lines of 25 traps(145 in total),the number of trapping sessions being one or several per year.We tested the hypotheses that:(1)any reaction to the multiple disturbances is species-specific,that is,the relative abundance of SM species and their proportion in the community differs with respect to the flood magnitude and habitat transformation,and(2)at the guild level,disturbances favor habitat generalists,thereby changing the characteristics of SM community.The average relative density of SM was 20.25 individuals per 100 trap nights(range 7.56–40.67),with 4-year-long cyclical changes of density observed.In separate years,we recorded from 4 to 9 species;Shannon’s diversity index varied from 0.46 to 2.19,with expressed change of the dominant species.Habitat generalist species were favored,while habitat specialists were disadvantaged.As the meadow transformation progressed,unfavored states in the SM community prevailed,with excessive numbers of granivore and herbivore species present.Our study suggests that multiple disturbances may lead to an increase in relative abundance,species richness,and diversity within the SM assemblages.

Small mammal diversity and habitat requirements in the Kahuzi- Biega National Park and surrounding areas, eastern Democratic Republic of Congo

We conducted a study on diversity and habitat requirements of small mammals in the western part of the AlbertineRift, eastern Democratic Republic of Congo. The work aimed at providing a more complete list of species recordedto date and their habitat requirements to aid conservation efforts in the region. Trapping was conducted usingMuseum special, Victor traps, Sherman live traps and pitfall traps in four different habitats. A total of 57 specieswas recorded. Plantations and open habitats harbored the same species. In the forested areas we recorded 30 specieswhich are not tolerant to disturbance. Eighteen species are Albertine Rift endemics. One species (Lophuromyscinereus), which is vulnerable and data deficient, has been recorded only in swamp. This study has recorded morespecies than the previous studies, some of which have not been reported in earlier studies. Differences between thisand earlier studies are attributed to methods and the areas sampled. Some of the habitats sampled by previousworkers have not been assessed. More research is needed, especially in swamps in mountain areas and in deepforests inhabited by species not present at lower altitudes.

Diet analysis of small mammal pests: A comparison of molecular and microhistological methods

Knowledge of what pest species are eating is important to determine their impact on stored food products and to plan management strategies accordingly.In this study,we investigated the food habits of 2 rodents,Rattus rat­tus(ship rat)and Mus musculus castaneus(house mouse)as well as an insectivore,Suncus murinus(shrew),present in human dwellings.Both a microhistological approach and a DNA barcoding approach were used in the present study.Following DNA extraction,amplification was performed using group-specific primers target­ing birds,plants and invertebrates.Resulting polymerase chain reaction products were sequenced and analyzed to identify the different prey species present in the gut contents.The findings from the application of both tech­niques were in agreement,but the detection of prey type with each technique was different.The DNA barcoding approach gave greater species-level identification when compared to the microhistological method,especially for the invertebrate and avian prey.Overall,with both techniques,23 prey taxa were identified in the gut con­tents of the 3 species,including 15 plants,7 insects and a single bird species.We conclude that with a selection of suitable“barcode genes”and optimization of polymerase chain reaction protocols,DNA barcoding can pro­vide more accurate and faster results.Prey detection from either technique alone can bias the dietary informa­tion.Hence,combining prey information of both microhistological analysis and DNA barcoding is recommend­ed to study pest diet,especially if the pest is an omnivore or insectivore species.

Effects of macroparasites on the energy allocation of reproducing small mammals

Reproduction,including lactation,is the most costly activity in terms of energy expenditure in female mammals.Consequently,the energy requirements of the reproducing female may not be met at this time,especially if other energy demanding activities are occurring concomitantly.Such activities could be the activation and maintenance of an immune system in response to parasitic infestation.These protective processes are energetically demanding and require trade-off decisions among competing energy demands.In the case of a reproducing mammal,the trade-offs occur mainly between defence against parasites and reproductive costs of the host.In this paper,I discuss the effects of macroparasites on the energy allocation of reproducing small mammals.

High prevalence of Babesia microti in small mammals in Beijing

Background: Babesiosis is an emerging tick-borne zoonotic infectious disease.Babesia microti is responsible for most cases of human babesiosis globally.It is important to investigate the prevalence of B.microti in the mammalian host population of a specific region in order to elucidate mechanisms of pathogen transmission and to define geographic areas where humans face the greatest risk of exposure.The aim of this study is to understand the prevalence and genotypes of B.microti in the small mammals that are found in Beijing,China.Methods:: We trapped small mammals from all of the 16 urban,suburban,and outer suburban districts of Beijing during the years 2014,2017 and 2018.Genomic DNA was extracted from the heart tissues individually and the Babesia 18S rRNA gene was detected by PCR.The genotypes of B.microti were identified based on sequence alignments and phylogenetic analysis.The morphology of the parasites was observed under light microscopy.The risk factors were analyzed statistically based on both univariate analyses and multivariate logistic regression.Results: A total of 1391 small mammals were collected.Positive infection of B.microti was detected in 12.1%(168/1391)of small mammals from 15 out of the 16 districts.Both Kobe-type and U.S.-type B.microti,accounting for 9.5%and 2.7%,respectively,were identified.Classic diverse morphologic forms of B.microti were observed.Specific types of ecological habitats including shrub areas,broad-leaved forest,and cropland were revealed to be risk factors associated with B.microti infection.Conclusions: This study demonstrated the wide prevalence of B.microti infection in eight species of small mammals in Beijing,with Kobe-type more prevalent than U.S.-type.This study provides fundamental information for the development of informed prevention and control measures by public health authorities;the data gathered indicates a need for further monitoring of both clinical diseases in individuals presenting with babesiosis-like symptoms,as well as the infection status of ticks in high risk areas.

Predictors of the abundance of small mammals' parasitic fleas in households of Western Yunnan Province

Objective To analyze the predictors of the abundance of small mammals’parasitic fleas in households of Western Yunnan Province.Methods Eight hundred households of 40 natural villages from 10 counties in Western Yunnan Province were selected as study subjects.Five live-traps were placed in each household for

Diversity and distribution patterns of non-volant smallmammals along different elevation gradients on Mt. Kenya,Kenya

The distribution of small mammals in mountainous environments across different elevations can provide important information on the effects of climate change on the dispersal of species. However, few studies conducted on Afromontane ecosystems have compared the altitudinal patterns of small mammal diversity. We investigated the species diversity and abundance of non-volant small mammals(hereafter ‘small mammals')on Mt. Kenya, the second tallest mountain in Africa,using a standard sampling scheme. Nine sampling transects were established at intervals of 200 m on the eastern(Chogoria) and western(Sirimon) slopes.A total of 1 905 individuals representing 25 species of small mammals were trapped after 12 240 trap-nights.Abundance was highest at mid-elevations on both slopes.However, species richness and their distribution patterns differed between the two slopes. More species were recorded on Chogoria(24) than on Sirimon(17). On Chogoria, species richness was higher at mid-high elevations, with a peak at mid-elevation(2 800 m a.s.l.),whereas species richness showed little variation on the Sirimon slope. These results indicate that patterns of species diversity can differ between slopes on the same mountain. In addition, we extensively reviewed literature on Mt. Kenya's mammals and compiled a comprehensive checklist of 76 mammalian species. However, additional research is required to improve our understanding of smal mammal diversity in mountain habitats in Africa.

Expansion of Small Terrestrial Mammals and Their Parasites into the Barun Valley (Makalu Mt. Region, Nepal Himalaya) Linked with Changes in Glaciation and Human Activities

The article is based on collection of small terrestrial mammals(Soriculus nigrescens,Episoriculus caudatus, Neodon sikimensis,Alticola stoliczkanus, Niviventer eha and Ochotona roylei) collected in the Barun Valley, east Nepal in the pre-monsoon period of 1973.Zoogeographic and ecological characteristics and altitudinal stratification of these species are analysed, depending both on abiotic(geomorphological and climatic) and biotic(vegetation, and human presence and activities)factors. All the captured mammals were examined for ecto- and endoparasities. Infestations of Trombiculid mites and Ixodid ticks were tightly linked to the local habitat where these ectoparasites must survive during their nonparasitic phase. Analysis of their occurrence completes the reconstruction of migration routes during the expansion of small mammals into the Barun Valley and the exacerbating influence of human activities(summer pasturing,mountaineering expeditions and trekking parties).An indicator of anthropogenic influence was the occurrence of synantropic flies. The potential medical importance of these findings is discussed.It is assumed a possible occurrence of arboviruses transmitted by ticks and also rickettsioses(transmitted by ticks and chigger mites). As far bacteriological infections, plague cannot be excluded.