Socio-environmental factors associated with small mammal assemblage and Leptospira prevalence in Suburban Areas of Terengganu,Malaysia

Objective:To examine the socio-environmental factors associated with the assemblage of small mammals and the prevalence of Leptospira pathogen in poor suburban communities of Terengganu,Malaysia.Methods:We trapped small mammals from 119 trapping points scattered around three suburban communities of Terengganu using sausage-baited live traps.On the average,we set up five traps for three nights at each sampling point during the trapping period.Kidneys of captured animals were harvested and processed for Leptospira investigation.Additionally,environmental survey was conducted at each trapping point to obtain information about possible variables supporting small mammal assemblage.We used a generalized linear model to evaluate the effect of different socio-environmental variables on small mammals’assemblage.Results:A total of 89 small mammals,specifically,Rattus norvegicus(n=39),Rattus rattus(n=27),Rattus exulans(n=10),Suncus murinus(n=11),and Tupaia glis(n=2)were captured from 1385 trap nights.Fourteen individuals(15.7%)of the captured animals tested positive for Leptospira bacteria using PCR detection.Results of our generalized linear model showed only residences bordering vacant lots as the variable positively associated with small mammal occurrence in the three study sites.Conclusions:Small mammal community,especially the often neglected species,could harbour and potentially contribute towards pathogenic Leptospira maintenance in the study sites.To adequately control small mammals’population and subsequent human zoonoses transmission,it is critical to advocate and promote appropriate infrastructure and suburban services,together with good hygiene practices that can reduce the animals’access to food and harborage.

Community Structure and Diversity Distributions of Small Mammals in Different Sample Plots in the Eastern Part of Wuling Mountains

Five years＇ （2000-2004） continuous study has been carried out on small mammals such as rodents in seven different sample plots, at three different altitudes and in six different ecological environment types in the eastern part of the Wuling Mountains, south bank of the Three Gorges of Yangtze River in Hubei. A total of 29 297 rat clamps/times were placed and 2271 small mammals such as rodents were captured, and 26 small mammals were captured by other means. All the small mammals captured belonged to 8 families 19 genera and 24 species, of which rodentia accounted for 70.83% and insectivora 29.17%. Through analysis of the data, the results showed that： 1 ） although the species richness had a trend of increasing along different sample plots as altitude increased from south to north, quite a few species showed a wide habitat range in a vertical distribution （ 15 species were dispersed over three zones and two species over two zones） , indicating a strong adaptability of small mammals such as rOdents at lower altitudes in most areas and comparatively less vertical span of entire mountains; 2） whether in seven different sample plots or six different ecological types, Apodemus agrarius and Rattus norvegicus were dominant species below 1200m, and Anourosorex squamipes, Niviventer confucianus and Apodemus draco were dominant above altitudes of 1300m, however, in quantity they were short of identical regularity, meaning they did not increase as the altitude did, or decrease as the ecological areas changed; 3）the density in winter was obviously greater than that in spring, and the distribution showed an increasing trend along with altitude, but the density in different sample plots was short of identical regularity, showing changes in different seasons and altitude grades had an important impact on small mammals such as rodents; 4） in species diversity and evenness index, there were obvious changes between the seven different sample plots, probably caused by frequent human interference in this area. Comparatively speaking, there was less human interference at high altitudes where vegetation was rich and had a high diversity and evenness index, and the boundary effect and community stability were obvious. Most ecological types have been seriously interfered with due to excessive assart at low altitudes with singular vegetation and low diversity and evenness index and poor community stability, showing an ecosystem with poor anti-reversion. If human interference can be reduced in those communities at high altitudes with low diversity and evenness index, the biological diversity in the communities will gradually recover to similar levels of other ecological areas.

Diversity of Sucking Lice on Small Mammals in the Surrounding Areas of Erhai Lake in Yunnan,China

An investigation of sucking lice on the body surface of small mammals was carried out in the surrounding areas of Erhai Lake in Dali, Yunnan from 2003 to 2004. From investigation sites, 3 303 small mammal hosts were captured and identified into 7 families, 15 genera and 21 species in 4 orders （Rodentia, Insectivora, Scandentia and Carnivora）, while t4 635 individuals of sucking lice collected from the body surface of the small mammal hosts are identified into 5 families, 6 genera and 21 species in the Order Anoplura, The sites stand alongside three cordilleras surrounding the Erhai Lake, namely Eastern Wuliang Mountain, Southern Ailao Mountain and Western Cangshan Mountain. The three confined oriented areas are different landscapes within the same zone where the longitude, latitude, altitude and fauna are homologous but isolated by Erhai Lake as inartificial barrier. The aim of this study was to recognize features of the species diversity, abundance, community structure, similarity and distribution of sucking lice in different landscapes within the same zone. The results showed the species diversity of sucking lice was very low with a very simple community structure. The distribution of sucking lice and their corresponding hosts are quite uneven among different oriented areas and this may imply that ecological environment influences the species composition and distribution of sucking lice and their corresponding hosts. A certain species of hosts usually have their fixed louse species. The similarity of sucking louse communities is highly consistent with the affinity of small mammal hosts in taxonomy. Species of sucking lice on the same small mammal host in different oriented areas of Erhai Lake are homologous. The results strongly suggest a close relationship of co-evolution between sucking lice and their hosts.

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.

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.

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.

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.

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.

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.

To a Question about Forecasting Number of Micromammalia （Rodentia）

In the present study, the data for population dynamics of micromammalia in Dnipropetrovs＇k Region in 1957-1999 and Dnipro-Orel＇s Natural Reserve at 1991-2009 are adduced. With the purpose to drawing up of the long-term forecast at number are analyzed long-term lines of number on background kind＇s fine micromammals of dominant group. The analysis of long standing rows of number small mammals and comparison data with Wolf number were demonstration, which indicate that dynamic of number phone species （and dominant in particular） carry a cyclic character and contact with 11-year cycles of sun activity. Consequently, it was clearing up hidden periodical in dynamic of number mouse rodents. By that observation was dependence from cycles of sun activity. Probably, that in 2012 year, before peak of sun activity in 2013, next high increase about the number of small mammals for maxima （＂outbreak＂ mass reproduction is a peak ＂big wave＂） will take place.

中国西藏发现麝鼩属(劳亚食虫目:鼩鼱科)两新物种

麝鼩属(Crocidura)是哺乳动物中物种数量最多的属。中国麝鼩属的分类存在诸多争议,需要进一步开展基础研究。本文整理了灰麝鼩(C.attenuata)、台湾灰麝鼩(C.tanakae)、安徽麝鼩(C.anhuiensis)、白尾梢大麝鼩(C.dracula)、大麝鼩(C.lasiura)、黑袍麝鼩(C.pullata)和2个疑似新种共8种大型麝鼩189号标本,比较了假剥制标本、头骨和牙齿形态,对测量数据进行了主成分分析(PCA)和判别分析(DA)。结合中国及邻近地区麝鼩属物种Cyt b基因的分子系统学和分子物种界定结果,我们描记了两个从中国西藏发现的麝鼩新种,即札达麝鼩Crocidura zhadaensis Chen,Wu et Liu,sp.nov.和墨脱麝鼩Crocidura medogensis Chen,Wu et Liu,sp.nov.。札达麝鼩的鉴定特征:头体长69~77 mm,尾长49~56 mm,颅全长20.04~20.74 mm。体色较浅,整体呈褐色。尾距尾基3/4长有稀疏的白色长针毛,尾末端形成短毛束。脑颅扁平,下关节面内侧卵圆孔大,第三上单尖齿(U3)明显大于第二上单尖齿(U2),第一上前臼齿(P4)原尖附近有一小凹陷。墨脱麝鼩的鉴定特征:头体长67~76 mm,尾长62~65 mm,颅全长20.33~22.21 mm。体色深,背毛深黑褐色,腹毛黑灰色;尾长,常超过头体长的85%;脑颅饱满,顶骨较隆起;第一上单尖齿(U1)最大,高度约是第二上单尖齿(U2)和第三上单尖齿(U3)的两倍;第一上臼齿(M1)的次尖舌面侧缘延展呈半月形;乳突明显。为进一步厘清中国麝鼩物种的分类和物种多样性,本文编制了它们的物种检索表。

2021—2023年青岛市小兽携带鼠传病原体监测分析

目的调查青岛市小兽携带病原体基本情况,为鼠传疾病的防控工作提供理论依据。方法2021—2023年在青岛市西海岸新区、即墨区、胶州市、平度市和莱西市采集小兽肝、脾、肾和肺组织的核酸样本,采用实时荧光定量PCR(Quantitative Real-time PCR,qPCR)检测致病性钩端螺旋体和巴尔通体,反转录实时荧光定量PCR(Reverse transcription-qPCR,RT-qPCR)方法检测汉坦病毒和新型布尼亚病毒。对种群构成比、病原体感染率进行统计学分析。结果本次共捕获小兽624只,其中褐家鼠最多,占比为4311%,小家鼠占比为3686%、黑线姬鼠占比为1394%、鼩鼱占比为609%。病原学检测结果显示,鼠传病原体中汉坦病毒感染率为337%,致病性钩端螺旋体感染率为096%,巴尔通体感染率为112%;未检出新型布尼亚病毒。褐家鼠和小家鼠均检出3种病原体,以褐家鼠携带病原体感染率最高;监测生境中农田耕地生境鼠病原体检出感染率最高为820%。结论青岛市存在汉坦病毒、巴尔通体、致病性钩端螺旋体的鼠传病原感染情况,应加强农村地区的鼠传病原体监测和防控工作,降低人群鼠传病原体的感染风险。

长青国家级自然保护区中低山小型兽类物种多样性垂直分布格局

海拔梯度下的垂直分布格局是研究物种多样性分布规律的重要关注点之一。为了解长青国家级自然保护区小型兽类的垂直分布格局,本研究于2022年6月至2023年6月,采用夹日法并辅以陷阱法,按照200 m垂直梯度在海拔800~2423 m内连续设置8个海拔带40个样点,累积布夹8858夹次,陷阱240桶次。结果显示:(1)共捕获小型兽类357只,隶属3目7科13属20种,包括啮齿目16种、劳亚食虫目和兔形目各2种,保护区增加5个新纪录物种;(2)Shannon-Wiener和Simpson指数均显示物种多样性在中、低海拔地区最高,小型兽类群落主要由华南针毛鼠(Niviventer huang)、北社鼠(Niviventer confucianus)和中华姬鼠(Apodemus draco)组成;(3)物种相对多度和插值矫正丰富度的回归拟合为显著的一元三次曲线模型(P<0.01),高峰值(5.55%,13)出现在海拔1200 m左右,显示物种多样性在低海拔地区最高。长青保护区中低山小型兽类物种多样性垂直分布格局呈明显的左偏倚中峰模式,提示保护区今后也应重视对低海拔段的保护与管理。

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.

青海高原地区小型兽类7种病原体携带情况调查研究

目的了解青海高原地区伯氏疏螺旋体、问号钩端螺旋体、斑疹伤寒立克次体、恙虫病东方体、嗜吞噬细胞无形体、土拉弗朗西斯菌及巴贝虫7种病原体在小型兽类中的流行状况,为当地人兽共患疾病风险评估和预警提供科学依据。方法2018年6-7月,我们采用夹夜法在青海省海西蒙古族藏族自治州、海北藏族自治州及玉树藏族自治州的6个镇(区)捕获小型兽类,无菌收集其肝脏、脾脏和肾脏组织,采用实时荧光定量PCR法进行细菌性病原体的检测,采用普通PCR法进行巴贝虫的检测,对阳性PCR产物进行序列测定和分析。χ^(2)检验或Fisher确切概率法比较不同小型兽类、生境的病原体检出率差异。结果共捕获15种235只小型兽类,检出伯氏疏螺旋体、问号钩端螺旋体和巴贝虫,未检出其他病原体。伯氏疏螺旋体在长尾仓鼠、大林姬鼠、高原鼠兔、小家鼠、子午沙鼠、普通田鼠、仓鼠、间颅鼠兔、五趾跳鼠等9种41只小型兽类中检出,阳性率为17.45%(41/235);问号钩端螺旋体在长尾仓鼠、小家鼠、普通田鼠和根田鼠中检出,阳性率为3.40%(8/235),巴贝虫仅在1只香鼬中检出,阳性率为0.85%(1/235),不同病原体检出率差异有统计学意义(χ^(2)=200.54,P<0.001)。伯氏疏螺旋体在林区检出率最高,与其他生境差异有统计学意义(Fisher确切概率法,P<0.05)。3只普通田鼠和2只长尾仓鼠中存在伯氏疏螺旋体和问号钩端螺旋体混合感染的情况。巴贝虫阳性标本测序成功,基因序列系统发育分析显示为Babesia vulpes。结论青海高原地区小型兽类中检测出伯氏疏螺旋体、问号钩端螺旋体和巴贝虫,对人有潜在致病性,当地应加强相应人兽共患疾病的监测,并制定相应的防控措施。

海拔梯度变化对四川西岭雪山小型兽类群落的影响研究

2022年5—10月,利用夹夜法和陷阱法对四川西岭雪山小型兽类群落的海拔梯度变化进行了研究,在海拔1000~4600 m设置102个样方,捕获小型兽类32种884只。以400 m海拔梯度分析小型兽类群落:随海拔梯度升高,群落第一优势种形成了从北社鼠Niviventer confucianus(海拔1000~1800 m),转变成中华姬鼠Apodemus draco(海拔1800~3400 m),再到松田鼠属未定名种Neodon sp.(海拔3400 m以上)的替换现象;物种多样性垂直分布格局为中峰格局,物种丰富度在海拔1800~3400 m最高;发现松田鼠属Neodon一新物种,确认壮鼩鼹Uropsilus ro‑bustus Wan,2015新种地位成立。本研究强调了对完整海拔梯度进行全面抽样调查的重要性,从而能够较为客观地反映真实的生物多样性海拔分布格局。

哺乳动物小卵泡卵母细胞体外成熟的研究进展

体外成熟是哺乳动物胚胎工程获得成熟卵母细胞的主要途径,卵母细胞质量直接影响早期胚胎发育,妊娠的建立及维持,胎儿的发育等。哺乳动物卵巢表面数量众多的小卵泡可以作为胚胎工程卵母细胞的来源,但从哺乳动物卵巢获取的卵母细胞成熟差异较大,存在处于发育各个时期的卵母细胞,小卵泡卵母细胞体外成熟质量差,发育能力不足。如何提高小卵泡卵母细胞体外成熟的发育能力以充分挖掘优良母畜的遗传资源,提高胚胎工程效率成为研究热点。基于此,文章概述哺乳动物小卵泡卵母细胞体外成熟的研究进展,比较大、小卵泡卵母细胞物质积累差异、卵泡的卵泡液成分及含量差异以及卵泡颗粒细胞和卵丘细胞的差异,分析哺乳动物小卵泡卵母细胞体外成熟质量差的原因,分析总结提高哺乳动物小卵泡体外成熟卵母细胞发育能力的措施,包括抑制核成熟、成熟前培养、颗粒细胞及卵丘细胞与卵母细胞共培养,期望能够为小卵泡卵母细胞发育调控机制的研究及发育能力的提高提供理论指导。

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.

深圳机场小型兽类组成、多样性及时空变化

野生动物与飞机撞击对全球航空业造成日益增加的风险和经济损失(DeVault et al.,2011;Blackwell et al.,2013;Metz et al.,2020)。据中国民用航空局(CAAC)统计《鸟击飞机信息分析报告》显示,鸟击事故从2007年的326起增加到2016年的4618起,造成严重的安全风险和经济损失(Hu et al.,2020)。