Small Mammal Density Research Articles

Diversity, abundance and habitat association of small mammals in Maze National Park, Ethiopia

We investigated species composition, relative abundance, habitat association and density of small mammals in Maze National Park, Ethiopia. Data were collected using the capture-mark-recapture technique in three representative habitat types (grassland, bushland and riverine forest) from November 2021 to August 2022. Descriptive statistics and indices for diversity and evenness were used to analyse the data. A total of 679 rodents and insectivores were collected during a span of 2 646 trap nights. Of these, 534 (76.64%) individuals were newly captured, while 145 (23.36%) were recaptures. Overall trap success was 20.18%. Five species of rodents were captured: four from the family Muridae (Mastomys natalensis, Arvicanthis niloticus, Rattus rattus and Lemniscomys macculus) and one (Xerus rutilus) from the family Sciuridae; and one insectivore species (Elephantulus rufescens) from the family Macroscelididae. Mastomys natalensis (178; 33.3%) was the most abundant, while X. rutilus (1; 0.2%) and E. rufescens (1; 0.2%) were the least abundant. Small mammal species varied significantly with habitat types (χ2 = 6.101, df = 2, p ≤ 0.05), with the highest count in the bushland habitat (197; 36.89 %) and the lowest in riverine forest (152; 28.46%). The bushland and riverine forest habitats supported the highest (H’ = 1.04) and the lowest (H’ = 0.506) diversity of small mammal species, respectively. A relatively high number of small mammal species were caught during the wet season (n = 336) compared to the dry season (n = 198). Future studies using more trapping grids covering additional habitat types and genetic analyses for small mammal species confirmation are necessary for a better understanding of the Park’s small mammal fauna.

Assessment of the Current State of the Hissar High-Mountain Natural Plague Focus in the Republic of Tajikistan

The review is devoted to discussing the results of survey in the Hissar high-mountain natural plague focus on the territory of the Republic of Tajikistan in 2015–2023. Regular examination of the focus was carried out in 1970–1991. According to its results, the main carrier of the plague pathogen was the juniper vole, in the population of which a strain of the non-main subspecies central asiatica (0.PE4) of Hissar biovar (0.PE4h) was steadily circulating, the strain considered avirulent for humans. During that period, 853 strains were isolated in the focus, of which 799 (93.7%) were from the juniper vole and its fleas. Secondary carriers – the silver vole, the pygmy wood mouse, and the gray hamster – were rarely involved in epizootics. The red marmot, which has epidemiological significance due to its hunting by the local population, occupies a special position in the focus. Socio-political phenomena at the end of the 20th – early 21st century caused a long break in the work of the Tajik Plague Control Station. In 2008, the Station was transformed into the Republican Center for Combating Quarantine Diseases under the Ministry of Health and Social Protection of the Population of the Republic of Tajikistan. In 2015, studies were resumed, but carried out on a small scale. In 2021–2023, epizootiological monitoring in the Hissar focus was performed jointly with Russian specialists with the testing of field material samples for plague and other natural-focal infections. Currently, against the background of low numbers and population density of small mammals and their blood-sucking ectoparasites – potential carriers and vectors of zoonoses – the circulation of agents of plague, tularemia, pseudotuberculosis, tick-borne viral encephalitis, Ixodidae tick-borne borreliosis, human granulocytic anaplasmosis, human monocytic ehrlichiosis has not been registered. Markers (DNA) of causative agents of leptospirosis and intestinal yersiniosis have been identified. Joint Tajik-Russian cooperation on issues of ensuring the epidemiological well-being of the population of the Republic of Tajikistan must be continued.

Environmental heterogeneity modifies the link between personality and survival in fluctuating small mammal populations.

Despite numerous studies examining the fitness consequences of animal personalities, predictions concerning the relationship between personality and survival are not consistent with empirical observations. Theory predicts that individuals who are risky (i.e. bold, active and aggressive) should have higher rates of mortality; however, empirical evidence shows high levels of variation in behaviour-survival relationships in wild populations. We suggest that this mismatch between predictions under theory and empirical observations results from environmental contingencies that drive heterogeneity in selection. This uncertainty may constrain any universal directional relationships between personality traits and survival. Specifically, we hypothesize that spatiotemporal fluctuations in perceived risk that arise from variability in refuge abundance and competitor density alter the relationship between personality traits and survival. In a large-scale manipulative experiment, we trapped four small mammal species in five subsequent years across six forest stands treated with different management practices in Maine, United States. Stands all occur within the same experimental forest but contain varying amounts of refuge and small mammal densities fluctuate over time and space. We quantified the effects of habitat structure and competitor density on the relationship between personality traits and survival to assess whether directional relationships differed depending on environmental contingencies. In the two most abundant species, deer mice and southern red-backed voles, risky behaviours (i.e. higher aggression and boldness) predicted apparent monthly survival probability. Mice that were more aggressive (less docile) had higher survival. Voles that were bolder (less timid) had higher survival, but in the risky forest stands only. Additionally, traits associated with stress coping and de-arousal increased survival probability in both species at high small mammal density but decreased survival at low density. In the two less abundant study species, there was no evidence for an effect of personality traits on survival. Our field experiment provides partial support for our hypothesis: that spatiotemporal fluctuations in refuge abundance and competitor density alter the relationship between personality traits and survival. Our findings also suggest that behaviours associated with stress coping and de-arousal may be subject to density-dependent selection and should be further assessed and incorporated into theory.

Douglas fir and Norway spruce have similar effects on small mammal density, but not survival, in Central European managed forests

In an effort to ameliorate the impacts of climate change, forest managers in Central Europe increasingly turn to conifer species that produce higher yields and are better adapted to projected future climatic conditions. Though small mammals are an important component of the forest ecosystem, the impacts of enriching native broadleaf forests with conifers on small mammal communities are not well understood. We conducted mark–recapture surveys of small mammals to ascertain differences in their community structure among stands of two conifers (native Norway spruce Picea abies and non-native Douglas fir Pseudotsuga menziesii) and the dominant broadleaf in the region, European beech (Fagus sylvatica). After estimating the density of two common species, the yellow-necked mouse Apodemus flavicollis and bank vole Clethrionomys glareolus, we found that the population density of each is positively related to the proportion of beech and negatively to the proportion of conifers in each stand, though these effects of stand composition are smaller than the positive effect of herb cover. Increasing Norway spruce proportion reduced monthly survival of small mammals, while Douglas fir proportion had a positive effect on survival. We conclude that the two conifer species have similar impacts on small mammal density, though overall small mammal survival was significantly lower on plots with Norway spruce. This suggests that increasing the proportion of Douglas fir at the expense of Norway spruce may be possible without significantly changing local patterns of small mammal population density, but further research is necessary to elucidate the exact impacts of these two conifer species on small mammal demography and behavior.

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.

Spatiotemporal changes in small mammal community of Wenchi highlands, central Ethiopia

Small mammals show prominent spatial and temporal fluctuations. A study was conducted to assess the spatiotemporal dynamics of small mammals in Wenchi highlands, central Ethiopia. Sherman and snap traps were used to capture small mammals from four forests (Qibate, Lakeshore, Erica and Albesa), Hagenia woodland and Erica scrub in two dry and wet seasons between August 2019 and January 2021. A total of 959 small mammals represented by 12 rodent species (Arvicanthis abyssinicus, Desmomys yaldeni, Mastomys natalensis, M. awashensis, Stenocephaylemys albipes, Lophuromys flavopunctatus, L. brevicaudus, L. chrysopus, Dendromus lovati, Lophiomys imhausi, Graphirius murinus and an unidentified murid rodent), and 3 shrew species (Crocidura bailey, C. fumosa and C. olivieri) were recorded. Small mammals showed spatiotemporal variations. More individuals were trapped during the dry (58.29%) than the wet (41.71%) season. Lakeshore Forest yielded the highest number of small mammals, whereas Erica Forest contributed the least during both seasons. More small mammal individuals were trapped in the second (52.24%) than the first (47.75%) trapping year. Small mammals also showed significant variations between the trapping periods (P<0.05). High number of small mammals was trapped during the morning (84.98%) than evening traps. Seasonal differences in sexes and age groups were non-significant (P>0.05). The density of small mammals varied between seasons and habitats. Small mammals had higher density during the dry (83.33 ha-1) than the wet (59.35 ha-1) season. In conclusion, Wenchi highlands supported a diverse small mammal community that displayed spatiotemporal changes. As a result, priority should be given to conserve the area.

Diversity and Density of Small Mammal Species with Different Seasons and Habitats in Federal University Gashua, Yobe State, North-east Zone of Nigeria

The study examined diversity and density of small mammal species with different seasons and habitats in Federal University Gashua, Yobe State, North-East, Nigeria. The university environment was divided in to four (4) habitat types, namely; University residential area (URA), Acacia woodlot (AWL), Lake Area (LA) and Farm Land (LF) were used for the study. Small Mammal species survey was carried out for the period of six (6) months from August to October, 2022 (wet season) and January, to March, 2023 (dry season). Capture Mark–Recapture (CMR) and indirect observations methods were adopted; Survey was conducted using spring door traps of different sizes set at the habitat types during late evening hours 6:00 pm and checked in the morning hours from 6:00-8:30am for four (4) days per week with each habitat types being visited one day per week, making total of (96) man-days. Each habitat type was visited twice a day (morning and evening) which gave a total of (65;60) trapping night in both wet and dry seasons, the number decreased to 60 trapping night in the dry season was due to the wearing a way of vegetation cover. (32) Visits per habitat types and one (1) night survey per month. A total of ten (10) species of small mammals belonging to ten (10) families and seven (7) orders were recorded in the study. African Hedgehog Atelerix albiventris and White toothed shrew Crocidura flavescens were the most occurring species across The findings of the study shows that the overall diversity index was (1.692), where Four-toed hedgehog Atelerix albiventris had the highest species diversity90.363) and estimated population density of (64.44) followed by Giant pouched rat Cricetomys gambianus with (0.277; 0.018) respectively, Cape hare Lepus capensis and Mongoose Herpestes ichneumon who’s having the lowest diversity of (0.017) with (0. 564) density each in the study area. The month of February has higher number of captured percentage with (24%) in dry season, followed by October with (19%) in the wet season, the lowest capture percentage occurred with August (14%) in the wet season. University Residential Area had more number of individual species having (37.82 %), while Farm land had the least captured percentage of(16.85%).The trap success in both wet season and dry season’s period were (33.04%; 21.67%)respectively. Habitat alteration and destruction due to ongoing constructions project, mainly for university deployment might have accounted for small mammal species low diversity and density in Federal University Gashua.

Demography and reproductive seasonality of small terrestrial mammals in two forest ecosystems in Ghana

AbstractWe examined the effects of habitat types (farmlands, open forests and closed forests) and seasons on the population demography and reproduction of small terrestrial mammals in two tropical evergreen forests [Atewa Range Forest Reserve (ARFR) and Bimpong Forest Reserve (BFR)] environments in 2018 and 2019. Small mammals were trapped with Sherman's collapsible traps on transects across land use types and seasons to measure change in the relative density, sex ratio, age structure, juvenile recruitment and breeding probability. Twenty‐two (22) species of 506 small mammals (16 rodents and six shrews) were recorded in this study. Relative density of small mammals (captures/100 trap nights) was highest (p < 0.05) in the farmland [ARFR (3.48); BFR (2.36)] than the open forest [ARFR (1.96); BFR (0.65)] and closed forest [ARFR (1.13); BFR (0.98)] habitats in both forest ecosystems. Overall sex ratio was male‐skewed (1.03:1) in the study. ARFR recorded higher female ratios in all habitat types [farmland (1:1.2); open forest (1:1.04); closed forest (1:1.3)] and seasons than males. Male sex ratio was high in all habitat types and seasons in the BFR. Majority of individuals captured in the habitat types [farmland (1.5:1); open forest (1.1:1); closed forest (1.5:1)] and seasons were adults. Over 90% of all captured adults in the study areas were actively breeding. The closed forest habitat type had the highest proportion (0.93) of actively breeding small mammals in the study forests. Seasonally, there were more species actively breeding in the wet season in ARFR and dry season in BFR. Majority of the small mammal captured (n = 268 recorded for ARFR and n = 168 for BFR) were adults. Juvenile recruitment (proportion of juveniles/total capture) was low for all the study forests (with mean proportions of 0.11, 0.04 and 0.03 for closed forest, farmland and open forest, respectively, in ARFR and 0.05, 0.03 and 0.07 for closed forest, farmland and open forest, respectively, in BFR) and seasons. Anthropogenic activities degrade ecosystems, change population demography and favour habitat generalists and pest species.

Habitat and Season Drive Chigger Mite Diversity and Abundance on Small Mammals in Peninsular Malaysia.

Chigger mites are vectors of the bacterial disease scrub typhus, caused by Orientia spp. The bacterium is vertically transmitted in the vector and horizontally transmitted to terrestrial vertebrates (primarily wild small mammals), with humans as incidental hosts. Previous studies have shown that the size of the chigger populations is correlated with the density of small mammals in scrub typhus-endemic regions. Here, we explore interactions between the small mammals and chiggers in two oil palm plantations located in the Perak and Johor states of Peninsular Malaysia. The location in Perak also contained an aboriginal (Orang Asli) settlement. A ~5% sub-sample from 40,736 chigger specimens was identified from five species of small mammals (n = 217), revealing 14 chigger species, including two new records for Malaysia. The abundance and species richness of chiggers were significantly affected by habitat type (highest in forest border), state (highest in Perak), and season (highest in dry). The overall prevalence of Orientia tsutsugamushi DNA in small-mammal tissues was 11.7% and was not significantly affected by host or habitat characteristics, but in Johor, was positively associated with infestation by Leptotrombidium arenicola. These findings highlight the risk of contracting scrub typhus in oil palm plantations and associated human settlements.

The circulation ofAnaplasma phagocytophilumecotypes is associated with community composition of vertebrate hosts

AbstractAnaplasma phagocytophilumis a tick‐borne pathogen that has been detected in many tick and vertebrate species. It is among the most widespread tick‐borne pathogens in animals in Europe. The bacterium can be genetically divided into four ecotypes, which are linked to distinct but overlapping host species. However, knowledge about the transmission dynamics of the enzootic cycles of the different ecotypes is limited. Here, we quantified the link between the ecotypes ofA. phagocytophilum, the different life stages of the tickIxodes ricinus, and vertebrate host groups through a meta‐analysis. We extracted data on the meanI. ricinusburden and theA. phagocytophiluminfection prevalence in both hosts and feedingI. ricinusfrom 197 papers on 77 wildlife species. With this information, we modeled the relative importance of different host taxonomic groups for the circulation of the different ecotypes ofA. phagocytophilumin a theoretical assemblage of hosts with varying presence of red deer (Cervus elaphus) and densities of small mammals. We showed that the composition of the vertebrate community affects the relative abundance of different ecotypes ofA. phagocytophilumin the different life stages ofI. ricinus. The presence of red deer is likely to increase the infection prevalence of Ecotype 1 in ticks, while small mammal densities drive the prevalence in ticks of mainly Ecotype 3, and to a lesser extent Ecotype 1. In Europe, vertebrate communities are changing, with an increase in red deer abundance and changes in the population dynamics of small mammals. Our results suggest that these changes could imply an increase in the circulation ofA. phagocytophilumand thus an increase in the risk for public and veterinary health.

Estimating the density of small mammals using the selfie trap is an effective camera trapping method

Camera trapping to study wildlife allows for data collection, without the need to capture animals. Traditionally, camera traps have been used to target larger terrestrial mammal species, though recently novel methods and adjustments in procedures have meant camera traps can be used to study small mammals. The selfie trap (a camera trapping method) may present robust sampling and ecological study of small mammals. This study aimed to evaluate the selfie trap method in terms of its ability to detect species and estimate population density. To address this aim, standard small mammal live trapping was undertaken, immediately followed by camera trapping using the selfie trap. Both methods were set to target the arboreal sugar glider (Petaurus breviceps) and semi-arboreal brown antechinus (Antechinus stuartii). The more ground-dwelling bush rat (Rattus fuscipes) was also live trapped and recorded on camera. Across four survey areas, the probability of detection for each of the three species was higher for selfie traps than for live trapping. Spatially explicit capture-recapture models showed that selfie traps were superior at estimating density for brown antechinus and sugar gliders, when compared to simulated live trapping data. Hit rates (number of videos per various time intervals) were correlated with abundance. When correlating various hit rate intervals with abundance, the use of 10-min hit rate was best for predicting sugar glider abundance (R2 = 0.94). The abundance of brown antechinus was estimated from selfie traps using a 24-h hit rate as a predictor (R2 = 0.85). For sugar gliders, the selfie trap can replace live trapping as individuals can be identified through their unique facial stripes and natural ear scars, and thus used in capture-recapture analysis. This method may be useful for monitoring the abundance of other small mammal species that can also be individually recognized from photographs.

NEW OBSERVATIONS OF STOAT (Mustela erminea L.) IN BOSNIA AND HERZEGOVINA

UDK: 599.742.4(497.6)
 The Stoat occupies a wide range of habitats. It is often found in successional or forest-edge habitats, in the scrub, alpine meadows, marshes, riparian woodlands, hedgerows, and riverbanks that have high densities of small mammals, especially Microtus and Arvicola voles (KİNG, 1983). PULLİAİNEN, (1999) stated that coniferous and mixed woodlands are preferred, but that many other habitats are used including tundra and the summits of fells and mountains. Dense forests and deserts are avoided (KİNG, 1983). Although mentioned in all to-day's Laws on Hunting (1893 – 2014) in Bosnia-Herzegovina, there are not so many records of this species or official reports in hunting bag. Considering its geographic range (IUCN 2020), in Bosnia-Herzegovina, the stoat is recorded only in the western and northern parts of the country. İn this paper, we presented new localities where the stoat was observed in Bosnia-Herzegovina, as well as types of habitats where it was recorded.

Raiders of the last ark: the impacts of feral cats on small mammals in Tasmanian forest ecosystems.

Feral individuals of the cat Felis catus are recognized internationally as a threat to biodiversity. Open, non-insular systems support a large proportion of the world's biodiversity, but the population-level impacts of feral cats in these systems are rarely elucidated. This limits prioritization and assessment of the effectiveness of management interventions. We quantified the predatory impact of feral cats on small mammals in open, non-insular forest systems in Tasmania, Australia in the context of other factors hypothesized to affect small mammal densities and survival, namely the density of a native carnivore, co-occurring small mammals, and rainfall. Change in feral cat density was the most important determinant of small mammal density and survival. We calculated that, on average, a 50% reduction in feral cat density could result in 25% and 10% increases in the density of the swamp rat Rattus lutreolus and long-tailed mouse Pseudomys higginsi, respectively. Low-level culling of feral cats that we conducted on two of our four study sites to experimentally alter feral cat densities revealed that swamp rat survival was highest when feral cat densities were stable. We conclude that feral cats exert downward pressure on populations of indigenous small mammals in temperate forest systems. However, alleviating this downward pressure on prey by culling a large proportion of the feral cat population is difficult as current methods for reducing feral cat populations in cool temperate forest systems are ineffective, and potentially even counterproductive. We suggest using an adaptive approach that regularly and robustly monitors how feral cats and small mammals respond to management interventions that are intended to conserve vulnerable prey species.

Evaluating livetrapping and camera-based indices of small-mammal density

Density estimates are integral to wildlife management, but they can be costly to obtain. Indices of density may provide efficient alternatives, but calibration is needed to ensure the indices accurately reflect density. We evaluated several indices of small-mammal density using livetrapping and motion-activated cameras in the Cascade Mountains of Washington (USA). We used linear regression to compare spatially explicit capture–recapture density estimates of mice (genus Peromyscus Gloger, 1841), voles (genera Microtus Schrank, 1798 and Myodes Pallas, 1811), and chipmunks (genus Neotamias A.H. Howell, 1929) with four indices. Two indices were based on livetrapping (minimum number alive (MNA) and number of captures per 100 trap-nights) and two indices were based on photos from motion-activated cameras (proportion of cameras detecting a species and number of independent detections). We evaluated how the accuracy of trap-based indices increased with trapping effort using subsets of the full dataset (n = 7 capture occasions per site). Most indices provided reliable indicators of small-mammal density, and livetrapping indices (R2 = 0.64–0.98) outperformed camera-based indices (R2 = 0.24–0.86). All indices performed better for more abundant species. The effort required to estimate each index varied and indices that required more effort performed better. These findings should help managers, conservation practitioners, and researchers select small-mammal monitoring methods that best fit their needs.

Small mammal responses to wetland restoration in the Greater Everglades ecosystem

Wetlands have experienced dramatic losses in extent around the world, disrupting ecosystem function, habitat, and biodiversity. In Florida's Greater Everglades, a massive restoration effort costing billions of dollars and spanning multiple decades is underway. As Everglades restoration is implemented in incremental projects, scientists and planners monitor the outcomes of projects. In this study, we evaluated the progress of a restoration project in the southwestern Everglades. We aimed to determine whether the presence and density of small mammals differed between areas with the hydrologic restoration of the ecosystem and areas without restoration. Our three focal species were: marsh rice rat (Oryzomys palustris), hispid cotton rat (Sigmodon hispidus), and cotton mouse (Peromyscus gossypinus). Using spatially explicit capture‐recapture models, we found greater densities of cotton mouse in restored habitat and lower densities of hispid cotton rat in sites with higher water levels. In addition, we found an increase in the presence of the marsh rice rat in restored areas compared to unrestored, but captures were too low to reliably assess significance. Our study provides evidence that ongoing restoration in the southwestern Everglades is already impacting the small mammal community.

Stand-scale responses of forest-floor small mammal populations to varying size, number, and location of retention tree patches

Retention forestry, the practice of maintaining stand legacies in harvested forests, is used to create more complex forest structure and positive biodiversity outcomes in managed forests. However, the relative effectiveness of different retention strategies at increasing forest structural complexity and populations of dependent wildlife species is not well understood. We used an experimental study to evaluate changes in the population density of three small mammal species in response to different size and location (riparian or upland) of retention tree patches within harvested forests in the Pacific Northwest, USA. We further assessed whether small mammal density varied in relation to differences in structural complexity within retention patches among experimental retention stands. Within stands, deer mice (Peromyscus spp.) population density did not differ between retention and harvested areas (β = −0.05, SE = 0.06), Townsend’s chipmunk (Neotamias townsendii) density was higher in retention compared to clearcut areas (β = 1.61, SE = 0.10), and creeping vole (Microtus oregoni) density was highest in clearcut areas (β = −0.68, SE = 0.10). At the stand-scale, deer mouse density and chipmunk density were lowest in stands with large upland patches of retention (mean = 83, SD = 28 trees) and highest in stands with multiple small patches of upland retention (mean = 8, SD = 2 trees). Creeping vole density followed the opposite pattern, highest in stands with large upland patches and lowest in stands with multiple small patches. Densities of each species were intermediate in stands where at least a portion of the retention trees were connected to forested riparian buffers. Relating the density of each species to structural complexity within stands revealed that Townsend’s chipmunk density increased with increasing retention tree blowdown (β = 0.39, SE = 0.08), a proxy for downed wood resources, whereas creeping vole density decreased (β = −0.51, SE = 0.12), and deer mice density did not change consistently (β = 0.00, SE = 0.08). Furthermore, retention tree mortality was highest in the experimental treatment with several small patches and lowest in the treatment with a single large patch. Our results demonstrate that adopting dispersed retention patch patterns increases the abundance of small mammals in managed, early-seral forests in the Pacific Northwest. This relationship is at least partly mediated through higher levels of structural complexity within small retention patches caused by increased retention tree blowdown compared to larger patches.

Tick-Borne Encephalitis Virus: Seasonal and Annual Variation of Epidemiological Parameters Related to Nymph-to-Larva Transmission and Exposure of Small Mammals.

A greater knowledge of the ecology of the natural foci of tick-borne encephalitis virus (TBEV) is essential to better assess the temporal variations of the risk of tick-borne encephalitis for humans. To describe the seasonal and inter-annual variations of the TBEV-cycle and the epidemiological parameters related to TBEV nymph-to-larva transmission, exposure of small mammals to TBEV, and tick aggregation on small mammals, a longitudinal survey in ticks and small mammals was conducted over a 3-year period in a mountain forest in Alsace, eastern France. TBEV prevalence in questing nymphs was lower in 2013 than in 2012 and 2014, probably because small mammals (Myodes glareolus and Apodemus flavicollis) were more abundant in 2012, which reduced tick aggregation and co-feeding transmission between ticks. The prevalence of TBEV in questing nymphs was higher in autumn than spring. Despite these variations in prevalence, the density of infected questing nymphs was constant over time, leading to a constant risk for humans. The seroprevalence of small mammals was also constant over time, although the proportion of rodents infested with ticks varied between years and seasons. Our results draw attention to the importance of considering the complex relationship between small mammal densities, tick aggregation on small mammals, density of infected questing nymphs, and prevalence of infected nymphs in order to forecast the risk of TBEV for humans.

A comparison of small mammal communities in two High-Andean Polylepis woodlands in Ecuador

Polylepis forest, historically widespread throughout high elevations of the central and northern Andes, now remain only in discontinuous small patches. An expanding agricultural frontier, along with other anthropogenic pressures, imperils these remnants through further isolation and loss of habitat quality. Using two grids of live traps we compared the populations of small nonvolant mammals in an intact Polylepis woodland with one nearby that had been logged 50 years before. Our study is the first to examine the effects of habitat degradation and associated changes to vertical complexity and habitat heterogeneity on mammalian communities in Polylepis woodlands above 3500 m. The intact woodland had significantly more vertical complexity than the mid-successional woodland. A total of 315 captures of 147 individuals of 9 species were sampled during an intensive trapping effort in 2010. Trap success was especially high averaging 35.4 % and 28.1 % in the intact and mid-successional woodland, respectively. Diversity and abundance of small mammals were greater in the intact woodland than the mid-successional site. Forest specialist species were more abundant in the intact habitat; while Thomasomys paramorum, a habitat generalist, was dominant in both. Habitat quality affected movement patterns of T. paramorum. The results affirm a high diversity and density of small mammals in intact Polylepis woodland and indicate that the effects of habitat disturbance are species dependent. We suggest that habitat specialists are more susceptible to loss of habitat heterogeneity and vertical complexity than habitat generalists.

Community reestablishment and poor body conditions of small mammal assemblages in subtropical afforested ecosystems

Afforestation is one of the high-efficiency practices for the restoration of degraded forest ecosystems and has been increasingly used worldwide. It is crucial to determine the restoration status of wildlife in afforested forests to effectively monitor biodiversity conservation and the self-sustainability of forest ecosystems, as well as to effectively guide the implementation of afforestation projects in the future. China has the largest area of man-made forests around the world, but the effects of the restoration efforts on the faunal diversity in artificial woodlands are unclear. Here, we evaluated the effects of afforestation practices on small mammals in two types of planted forests: Japanese larch (Larix kaempferi, an introduced species) and China Armand pine (Pinus armandii, a native species) plantations, and two reference forests: young- and old-growth forests, at the community, population, and individual levels. The diversity of small mammals did not differ significantly among the four forest types and the population densities of small mammals in two plantations were between the young- and old-growth forests. Collectively, our findings indicated that small mammal assemblages had reestablished in afforested forests. Four body condition indices were measured in the Chinese white-bellied rat (Niviventer confucianus), a predominant species, and differences were found between afforested and reference forests. Chinese white-bellied rats had the lowest body masses and highest endoparasite loads in the Japanese larch planted forest, while body length or carcass mass did not differ among the four forest types. In comparison, study rats had slightly lower body masses and lower endoparasite loads in the China Armand pine planted forest than reference forests. These findings indicated that small mammals inhabiting both types of afforested forests had poor body conditions but these trends were worse in the Japanese larch planted forest, i.e., the introduced species. Given that afforestation is a widespread practice for global forest landscape restoration, we propose two suggestions to guide afforestation efforts and the subsequent management thereof: (1) native species rather than exotic species are preferable for use in afforestation projects, and (2) wildlife diversity in afforested forests should be considered when monitoring the restoration and management of degraded forest ecosystems.

Effects of Sagebrush Restoration and Conifer Encroachment on Small Mammal Diversity in Sagebrush Ecosystem

Conifer encroachment in sagebrush ecosystems reduces habitat heterogeneity, niche space, and resource availability, all of which negatively affect many wildlife populations. Sagebrush restoration is recommended as a management action to mitigate conifer encroachment and restore wildlife across millions of hectares in the Great Basin. Despite this recommendation, the effects of conifer encroachment and sagebrush restoration are unknown for most wildlife species. Small nonvolant mammal communities include keystone species, consumers and prey; facilitate energy flow and ecological function; and provide important ecological goods and services. We assessed causal relationships between conifer encroachment and sagebrush restoration (conifer removal and seeding native plants) on small mammal communities over 11 yr using a Before-After-Control–Impact design. Sagebrush habitat supported an additional small mammal species, twice the biomass, and nearly three times higher densities than conifer-encroached habitat. Sagebrush restoration increased shrub cover, decreased tree cover, and density but failed to increase native herbaceous plant density. Restoration caused a large increase in the non-native, invasive annual cheatgrass (Bromus tectorum L.). Counter to prediction, small mammal diversity did not increase in response to sagebrush restoration, but restoration maintained small mammal density in the face of ongoing conifer encroachment. Piñon mice (Peromyscus truei), woodland specialists with highest densities in conifer-encroached habitat, were negatively affected by sagebrush restoration. Increasing cheatgrass due to sagebrush restoration may not negatively impact small mammal diversity, provided cheatgrass density and cover do not progress to a monoculture and native vegetation is maintained. The consequences of conifer encroachment, a long-term, slow-acting impact, far outweigh the impacts of sagebrush restoration, a short-term, high-intensity impact, on small mammal diversity. Given the ecological importance of small mammals, maintenance of small mammal density is a desirable outcome for sagebrush restoration.