Food partitioning between breeding White-tailed Kites (Elanus leucurus; Aves; Accipitridae) and Barn Owls (Tyto alba; Aves; Tytonidae) in southern Brazil.

I examined the diet of breeding White-tailed Kites (Elanus leucurus; Aves; Accipitridae) and Barn Owls (Tyto alba; Aves; Tytonidae) in an agrarian area of southern Brazil by analyzing regurgitated prey remains. The objective was to evaluate how these raptors, which differ markedly in their hunting activity periods (owls are nocturnal and kites diurnal), share their mammalian food component. 2,087 prey consumed by Barn Owls and 1,276 by White-tailed Kites were identified. They presented a high overlap of food-niches (Piankas index was 0.98). Based on the daily activity period of their main small mammal prey, a lower overlap would be expected. The crepuscular/nocturnal Mus musculus was the main prey for the diet of breeding Barn Owls (81%) and White-tailed Kites (63%). This small exotic rodent provided 63% of the small mammal biomass ingested by owls and 44% by kites. Larger native small mammals were also considered important for the diet of kites, mainly because of their biomass contribution. Although these raptors differ markedly in their hunting activity periods, Barn Owls and White-tailed Kites are very similar predators in southern Brazil, overlapping their diets.     

Wildflower areas within revitalized agricultural matrices boost small mammal populations but not breeding Barn Owls

Agro-ecosystems have recently experienced dramatic losses of biodiversity due to more intensive production methods. In order to increase species diversity, agri-environment schemes provide subsidies to farmers who devote a fraction of their land to ecological compensation areas (ECAs). Several studies have shown that invertebrate biodiversity is actually higher in ECAs than in nearby intensively cultivated farmland. It remains poorly understood, however, to what extent ECAs also favour vertebrates, such as small mammals and their predators, which would contribute to restoring functional food chains within revitalised agricultural matrices. We studied small mammal populations among eight habitat types—including wildflower areas, a specific ECA in Switzerland—and habitat selection (radiotracking) by the Barn Owl Tyto alba, one of their principal predators. Our prediction was that habitats with higher abundances of small mammals would be more visited by foraging Barn Owls during the period of chicks’ provisioning. Small mammal abundance tended to be higher in wildflower areas than in any other habitat type. Barn Owls, however, preferred to forage in cereal fields and grassland. They avoided all types of crops other than cereals, as well as wildflower areas, which suggests that they do not select their hunting habitat primarily with respect to prey density. Instead of prey abundance, prey accessibility may play a more crucial role: wildflower areas have a dense vegetation cover, which may impede access to prey for foraging owls. The exploitation of wildflower areas by the owls might be enhanced by creating open foraging corridors within or around wildflower areas. Wildflower areas managed in that way might contribute to restore functional links in food webs within agro-ecosystems.     

Impacts of Agriculture on the Diet and Productivity of Mackinder's Eagle Owls (Bubo capensis mackinderi ) in Kenya

Land conversion for agriculture is an increasing threat to biodiversity conservation, but its ecological effects on African birds is practically unknown. We investigated the impacts of agriculture on the diet and productivity of a small, disjunct population of Mackinder's eagle owls ( Bubo capensis mackinderi  ) in central Kenya. Owl diet was determined by analysis of pellets and other remains and compared to small mammal populations estimated by live trapping in two habitats. Small mammal abundance was low and averaged 7.4 small mammals/ha in farms and 0.5 small mammals/ha in grassland. Owls consumed a wide diversity of prey. The majority were mammals (87%) followed by birds (7%) and insects (5%). The percentage of small mammals in owl diet correlated positively with the relative abundance of small mammals during monthly trapping sessions. Diet composition did not influence owl breeding success. Farming activities affected owl diet composition through crop production. The amount of maize, peas, and carrots growing in farms was correlated with the abundance of Mastomys sp. and Procavia sp. in the owl's diet. Agricultural activities had a large effect on Mackinder's eagle owl diet by increasing the abundance of certain small-mammal prey and attracting owl prey to farms, though farming practices harmful to owls were observed.     

Extirpation of alternative prey during a small rodent crash

Summary We document two episodes, in different years, of Barn Owls (Tyto alba) preying on a winter population of Burrowing Owls (Athene cunicularia) on a southern California island. The predation in each case followed a marked shift in the diet of the Barn Owls, due to the cyclic decline of their normal small mammal prey. Heavy predation in the first year resulted in the extirpation of the Burrowing Owls on the island. Such heavy predation on alternative prey species is commonly reported in cyclic predator-prey systems, however this is the first documented case of extirpation of the alternative prey. Complete elimination of any prey species by terrestrial predators is, in fact, very rare.     

Spatial,road geometric and biotic factors associated with Barn Owl mortality along an interstate highway

Highway programmes typically focus on reducing vehicle collisions with large mammals because of economic or safety reasons, while overlooking the millions of birds that die annually from traffic. We studied wildlife–vehicle collisions along an interstate highway in southern Idaho, USA, with among the highest reported rates of American Barn Owl Tyto furcata road mortality. Carcass data from systematic and ad hoc surveys conducted in 2004–2006 and 2013–2015 were used to explore the extent to which spatial, road geometric and biotic factors explained Barn Owl–vehicle collisions. Barn Owls outnumbered all other identified vertebrate species of roadkill and represented > 25% of individuals and 73.6% of road‐killed birds. At a 1‐km highway segment scale, the number of dead Barn Owls decreased with increasing numbers of human structures, cumulative length of secondary roads near the highway and width of the highway median. The number of dead Barn Owls increased with higher commercial average annual daily traffic (CAADT), small mammal abundance index and grass rather than shrubs in the roadside verge. The small mammal abundance index was also greater in roadsides with grass vs. mixed shrubs, suggesting that Barn Owls may be attracted to grassy portions of the highway with more abundant small mammals for hunting prey. When assessed at a 3‐km highway segment scale, the number of dead Barn Owls again increased, with higher CAADT as well as with greater numbers of dairy farms. At a 5‐km scale, the number of dead Barn Owls increased with a greater percentage of cropland near the highway. Although human conversion of the environment from natural shrub‐steppe to irrigated agriculture in this region of Idaho has probably enhanced habitat for Barns Owls, it simultaneously has increased risk for owl–vehicle collisions where an interstate highway traverses the altered landscape. We review some approaches for highway mitigation and suggest that reducing wildlife–vehicle collisions involving Barn Owls may contribute to the persistence of this species.     

The feeding and breeding ecology of Barn Owls Tyto alba in Peninsular Malaysia

Barn Owls have only recently colonized Peninsular Malaysia, nesting in the roof spaces of houses in oil palm estates and feeding on the rats which inhabit these plantations. Pellet analysis showed that the prey spectrum was confined almost entirely to three species of the genus Rattus which are the major pests of oil palm. There was no annual variation in diet. Breeding showed a broad seasonality but occurred in all months of the year. Mean clutch and brood sizes of 6.6 and 4.6 respectively were recorded, most pairs producing two broods a year although on two occasions three were raised. Overall hatching success was 69.0% with first clutches more successful (79.9%) than second (57.3%). First broods fledged 86.1% and second broods 69.1% of young fledged. Comparison of growth rates of different sized broods suggested that there is a physiological maximum at which all broods proceed irrespective of brood size. The behaviour al changes needed in hunting techniques when colonizing dense plantations rather than the more usual open habitat of Barn Owls is discussed. The breeding strategy seems to be one of producing large clutches and broods, and frequent breeding attempts in a habitat with a high potential carrying capacity.     

Habitat selection by wintering male and female Snowy Owls on the Canadian prairies in relation to prey abundance and a competitor,the Great Horned Owl

Birds overwintering at high latitudes may find it challenging to meet their energy budgets when thermoregulatory costs are high and food availability is low. Snowy Owls (Bubo scandiacus), like most raptors, exhibit reversed sexual size dimorphism, so , if availability of high‐quality (food‐rich) habitats is limited, we predicted that larger and dominant females would use better ‐ quality habitat than males. During the winters of 2014–2015 and 2015–2016 in Saskatchewan , where many Snowy Owls overwinter annually, we measured prey (small mammal) abundance in fields with four types of cover, including cut stalks (stubble) of canola, grain and legume crops, and pasture, and related this estimate of quality to habitat selection by males and females. Small mammal abundance varied annually , but not among the three types of crop stubble. However, prey were less abundant in pastures than in the three types of crop cover in one of three years. Biweekly surveys of owls conducted during the two winters along a 60 ‐ km transect revealed weak selection for legume fields, especially by males. The home ranges of nine females with transmitters included proportionally less canola stubble than those of eight males with transmitters. Within home ranges, males avoided canola stubble and tended to use legume fields more, whereas females used all four habitat types in proportion to availability. Fewer Snowy Owls than expected were observed at locations along the transect within 800 m of Great Horned Owls (Bubo virginianus) and their associated habitats , suggesting that Snowy Owls also avoided these potential competitors on the landscape. Our results suggest that larger females outcompete smaller male Snowy Owls for home ranges in preferred habitat with less canola stubble because stubble‐free legume fields provide easier access to prey than canola fields with numerous rigid stalks.     

Habitat selection by a predator of rodent pests is resilient to wildfire in a vineyard agroecosystem

Conservation of uncultivated habitats can increase the potential for ecosystem services in agroecosystems, but these lands are also susceptible to wildfires in the arid western United States. In Napa Valley, California, abundant rodent pests and an interest in integrated pest management have led wine producers to use nest boxes to attract Barn Owls (Tyto furcata) to winegrape vineyards. The viability of this practice as a method to control rodent pests depends heavily on the amount of hunting effort that Barn Owls expend in vineyards, which is known to be influenced by the amount of uncultivated land cover types surrounding the nest box. Wildfires burned nearly 60,000 ha of mainly urban and uncultivated lands surrounding Napa Valley in 2017, altering Barn Owl habitats. We compared GPS tracking data from 32 Barn Owls nesting in 24 individual nest boxes before and after the fires to analyze their hunting habitat selection. Owls with burned areas available to them after the fires had home ranges that shifted toward the fires, but selection was not strongly associated with burned areas. Though there was some spatial use of burned areas, selection of land cover types was similar for birds before and after the fires and in burned and unburned areas. The strongest selection was for areas closest to the nest box, and most recorded locations were in grassland, though selection indicated that owls used land cover types in proportion to their availability. Overall, habitat selection was resilient to changes caused by wildfires. These results are important for farmers who use nest boxes as a means of rodent control, which may be affected after dramatic disturbance events, especially as wildfires increase in the western United States.     

FIRST ANNUAL REPORT ON THE RHODESIAN ORNITHOLOGICAL SOCIETY'S NEST RECORD SCHEME FOR THE YEAR ENDED 30 JUNE, 1956

MENDELSOHN, J. M. 1989. Habitat preferences, population size, food and breeding of six owl species in the Springbok Flats, South Africa. Ostrich 60:183-190.

Information on the habitat preferences, population size, food and breeding of Barn, Grass, Whitefaced, Marsh, Pearlspotted and Spotted Eagle Owls was obtained in a 6900-ha area in the Springbok Flats, South Africa. Seventy-two per cent of the area consisted of cultivated fields not usually used by owls. Hunting, roosting and nesting requirements were largely met in 1930 ha of verges, farmyards and patches of wood land ant grassland, here was an estimated total population of 303 owls in the area, giving an overall density of 22,7 ho/owl for the whole area or 6.4 ha/owl for those areas used by owls. These high densities were attributed to an abundance of Mastomys natalensis, the most important prey item for all except Pearlspotted Owls. Rates of predation on M. natalensis varied in relation to their population density, as indicated by rodent trapping results. Marsh Owls ate more insects in summer than at other times. Barn and Marsh Owls usuall laid in March-April and August-September, while other species started breeding in July-October. de timing of breeding of some owls may be related to changes in rates of recruitment of juvenile M. natalensis. Most Marsh Owl nests were placed on the southwestern sides of grass clumps or shrubs.     

乌鲁木齐市区越冬期长耳鸮的食性分析

2009～2011年间,利用食团分析法对乌鲁木齐市越冬长耳鸮(Asio otus)的食性进行分析。3年累计收集长耳鸮食团683份,辨认出1 132只猎物。分析结果表明,长耳鸮在冬季共捕食小型哺乳类6种,鸟类2种。小家鼠(Mus musculus)是最常见的食物,占总捕食量的53.45%。小型哺乳类是长耳鸮的主要食物,它在食物组成中出现的总频率为88.16%,以生物量计,小型哺乳类占食物构成的95.13%。长耳鸮的食物组成年度间差异显著,与当地猎物资源多样性和可获得性密切相关,表明长耳鸮可能采用机会主义者的捕食策略。     

Geographic variation of the winter diet of the Red Kite Milvus milvus in the Iberian Peninsula

This paper presents data on the winter diet of the Red Kite Milvus milvus in the Iberian Peninsula. The diet composition and its relationship with food abundance and habitat characteristics were studied in two areas (northern and southern plateaux) with different food availability and habitat composition. Red Kites showed a clear difference in diet between the two plateaux, with a higher consumption of carrion on the northern plateau and of game species on the southern plateau. Common Voles Microtus arvalis , despite being a very abundant prey on the northern plateau, did not appear in the diet in high numbers, but their frequency was related to the proportion of land occupied by nonirrigated (cereal) crops. High frequencies of "small" carrion (e.g. farmed Rabbits Oryctolagus cuniculus , poultry Gallus sp.) in the diet were correlated with a decrease in the trophic diversity which suggested an active choice of the food, at least in years with low vole densities. We suggest that the use of carrion is influenced not only by its abundance but by its availability to Red Kites. Refuse tips and muladares (dumps for dead livestock) and their management during the winter are important for the conservation of the species.     

Predator feeding ecology on Patagonian rocky outcrops: implications for colonies of mountain vizcacha (Lagidium viscacia)

On 10 rocky outcrops with mountain vizcacha colonies, diets and trophic relations of five predator species were analyzed to evaluate their impact in vizcacha populations. Diets included 17 prey items of which mammals represented 97% of biomass. Lagomorphs were the most important prey, followed by sigmodontines, tuco-tucos, and mountain vizcachas. The Barn Owl was a specialized predator, while the culpeo and lesser grison were generalized consumers. Predation of mountain vizcacha by Magellanic Horned Owls and culpeo foxes could increase vizcacha vulnerability because vizcacha populations are small and fragmented, and females produce only one offspring per year.     

Termites, Large Herbivores, and Herbaceous Plant Dominance Structure Small Mammal Communities in Savannahs

Large herbivores and termites are important functional groups in African savannahs. Both groups affect small mammals, which are also important determinants for savannah structure and function. Because vegetation on Macrotermes mounds are preferentially grazed by large herbivores, and mounds represent resource-rich distinct habitat patches for small mammals in relatively resource-poor savannahs, termite mounds are ideal sites for studies of how grazing by large mammals and productivity affect communities of small mammals. We conducted an experiment in Lake Mburo National Park, Uganda, with four treatments: large vegetated Macrotermes mounds (with and without large herbivores) and adjacent savannah areas (with and without large herbivores). We replicated the treatment blocks nine times and trapped small mammals regularly over a period of almost 2 years. Small mammal species assemblages differed considerably between mounds and savannah areas. Grazing had a substantial effect on small mammal species assemblages in the resource-poor savannah, but not in the relatively resource-rich termitaria. Small mammal species abundance, biomass, and richness were higher on termite mounds than adjacent savannah areas. Excluding large herbivores caused a major increase in species abundance, biomass, and richness both on savannah and termitaria. Herbaceous plant species evenness was an important determinant of the small mammal community. Small mammal biomass increased with high plant dominance, indicating that a few dominant plant species are important for biomass production of small mammals. Small mammal diversity was not related to any of the treatments, but increased with plant species evenness as well as richness. Fencing increased species dominance in the small mammal community on both savannah and termitaria, probably because competitive patterns shift from inter-guild (that is, between large and small mammals) to intra-guild (that is, between small mammals) when large mammals are excluded. The study highlights the complex interactions among large herbivores, termites, herbaceous plants, and small mammals in African savannahs. When studying the structure and function of small mammal communities it is therefore important to consider several coexisting functional groups.     

Small mammal species richness and turnover along elevational gradient in Yulong Mountain,Yunnan, Southwest China

Understanding the species diversity patterns along elevational gradients is critical for biodiversity conservation in mountainous regions. We examined the elevational patterns of species richness and turnover, and evaluated the effects of spatial and environmental factors on nonvolant small mammals (hereafter “small mammal”) predicted a priori by alternative hypotheses (mid‐domain effect [MDE], species–area relationship [SAR], energy, environmental stability, and habitat complexity]) proposed to explain the variation of diversity. We designed a standardized sampling scheme to trap small mammals at ten elevational bands across the entire elevational gradient on Yulong Mountain, southwest China. A total of 1,808 small mammals representing 23 species were trapped. We observed the hump‐shaped distribution pattern of the overall species richness along elevational gradient. Insectivores, rodents, large‐ranged species, and endemic species richness showed the general hump‐shaped pattern but peaked at different elevations, whereas the small‐ranged species and endemic species favored the decreasing richness pattern. The MDE and the energy hypothesis were supported, whereas little support was found for the SAR, the environmental stability hypothesis, and the habitat complexity. However, the primary driver(s) for richness patterns differed among the partitioning groups, with NDVI (the normalized difference vegetation index) and MDE being the most important variables for the total richness pattern. Species turnover for all small mammal groups increased with elevation, and it supported a decrease in community similarity with elevational distance. Our results emphasized for increased conservation efforts in the higher elevation regions of the Yulong Mountain.     

The effect of elevation and habitat cover on nest box occupancy and diet composition of Boreal Owls Aegolius funereus

Capsule: Diet composition of Boreal Owls Aegolius funereus was not affected by habitat cover, but it changed along the elevational gradient.

Aims: To assess the effect of elevation and habitat cover on nest box occupancy and diet composition of a central European population of Boreal Owls.

Methods: A Boreal Owl population was studied in the ?umava Mountains, Czech Republic, at elevations from 500 to 1300?m above sea level (asl), during 1984–2005.

Results: Boreal Owls occupied more frequently nest boxes above 600?m asl, but they did not clearly prefer any elevational band. Habitat cover did not affect the number of nesting attempts. There was also no relationship between habitat cover and diet composition. However, diet composition significantly changed along the elevational gradient. In particular, the proportion of alternative prey of Boreal Owls, i.e. birds and shrews Sorex sp., rose with increasing elevation. The proportion of voles Myodes and mice Apodemus in the diet decreased with increasing elevation. Among bird prey, the proportion of finches Fringillidae positively correlated with elevation.

Conclusions: Central European Boreal Owls did not show a clear preference for any habitat cover or elevational band, but the quality of the owls’ diet significantly decreased with increasing elevation.     

寒温带牧林交错区生境复杂度对啮齿类物种多样性的影响

采用铗日法对嫩江流域牧林交错区5个生境梯度中啮齿动物的多样性水平进行了研究,以探讨栖息地复杂程度对地面啮齿类物种多样性的影响.结果表明,黑线姬鼠、黑线仓鼠和大林姬鼠是嫩江流域牧林交错区中的优势种和常见种,不同物种在不同生境类型中呈明显的不均匀分布,反映了它们对不同生境的选择倾向性.同时,地面草本植物的覆盖度和丰富度对地面活动的小型哺乳动物的物种组成和群落结构具有较大的影响,啮齿动物的捕获率和生物量与草本植物的多样性水平呈现出显著的相关性关系,其物种丰富度随草本植物多样性指数的增加呈递增的趋势.此外,各生境中啮齿动物的物种多样性指数与草本植物多样性的相关关系并不显著,可能是因为灌丛区和林-灌交错区内大量的低矮灌丛与萌生丛改善了生境的隐蔽条件与食物资源,为更多物种的共存创造了良好的微环境,使得两生境中啮齿动物的物种多样性水平尤为突出.研究表明,小型啮齿动物的物种组成与栖息地的复杂程度有关,但地面植被对小型兽类生物量和物种多样性的影响力度并不是等同的,对地面小型兽类物种多样性影响的研究,统计生境复杂度或异质性时应考虑不同植被型/生境类型距地面的高度,不同植被型对小型兽类物种多样性的贡献程度随其距地面高度的增加而降低.     

Geographic and temporal variation in the consumption of bats by European Barn Owls

Capsule We report a review of the occurrence of bats in the Barn Owl diet Tyto alba in Europe. Based on 802 studies reporting 4.02 million prey items identified in pellets, 4949 were bats (0.12%). We found that bat predation decreased during the last 150 years, is more frequent on islands than mainland, and is higher in eastern than western Europe and in southern than northern Europe. Although Barn Owls usually capture bats opportunistically, they can sometimes specialize on them.     

The impact of vegetation characteristics and prey availability on breeding habitat use and diet of Little Owls Athene noctua in Central European farmland

Capsule Foraging habitats are determined by vegetation characteristics rather than the availability of insect prey.

Aims To determine the diet composition of Little Owls in relation to the availability of insects at foraging sites, and to elucidate the main factors determining the owls’ habitat choice.

Methods The feeding ecology of Little Owls was studied during the 2002 breeding season in the agricultural landscape of western Bohemia (Czech Republic), where its population is in decline. Diet composition was determined by pellet analysis. Insect availability was studied using pitfall traps in the two most important Little Owl foraging habitats. For both habitats, we assessed the main vegetative characteristics (average and maximum vegetation height, vegetation density).

Results Based on number, insects were the most dominant prey, followed by small mammals; based on weight, insects comprised only a minor part of the diet. Among insect prey, Carabidae beetles were the most abundant. The proportion of insect numbers was strongly positively correlated with advancing day of the season and negatively correlated with the proportion of vertebrates. Although the highest densities of Carabidae were found in cornfields Little Owls significantly preferred grassland habitats, probably because of the lower vegetation cover.

Conclusions The availability of short sward vegetation in grassland habitats during the breeding season may play a key role in the conservation of Little Owls in central European farmland.     

中国云南小兽寄生革螨的群落结构和空间分布

寄生在小兽体表的革螨可能是传播肾综合征出血热和立克次体痘等人兽共患病的媒介。本文报道了云南省28个县(市)小兽体表革螨的野外调查结果, 运用物种数、平均丰富度和Shannon多样性指数对小兽寄生革螨的群落特征和沿环境梯度的空间分布进行了研究, 并用系统聚类分析法 (SPSS 16.0软件)对18种主要小兽的革螨群落相似性进行了比较。在云南省28个县(市)共捕获到小兽14 544头, 隶属于5目（啮齿目、食虫目、攀鼩目、兔形目、食肉目）10科35属67种, 在捕获的小兽体表采集到革螨80 791头, 经鉴定属于10科33属112种。结果分析表明: 主要的宿主动物为黄胸鼠 Rattus tanezumi、齐氏姬鼠Apodemus chevrieri和大绒鼠Eothenomys miletus;纳氏厉螨Laelaps nuttalli、毒厉螨L. echidninus和贵州厉螨L. guizhouensis为革螨的优势种。齐氏姬鼠A. chevrieri、社鼠N. confucianus和黄胸鼠R. tanezumi体表寄生的革螨种类最多;臭鼩鼱Suncus murinus、齐氏姬鼠A. chevrieri和灰麝鼩Crocidura attenuata的革螨群落多样性最高。聚类分析结果表明, 大部分革螨群落的相似程度与相应小兽的亲缘关系及所处生态环境的相似性是基本一致的, 分类地位和生境选择相似的小兽, 它们的革螨群落也被聚为一类。革螨物种数沿纬度梯度的水平分布呈现两个峰值, 最大峰值出现在25°~26°N之间;沿海拔梯度的垂直分布呈单峰分布格局, 峰值在海拔2 000~2 500 m之间。革螨和小兽的多样性沿纬度梯度和海拔梯度的空间分布趋势也均表现出随着纬度和海拔的升高而先升高后降低的单峰型分布格局, 峰值分别出现在北纬25°~27°N和海拔2 000~2 500 m之间。结果提示云南革螨群落种类丰富, 多样性高。云南革螨物种数和多样性的分布格局可能直接受到古北和东洋两区系边缘效应的影响。     

三峡水库运行后洞庭湖洲滩 小型兽类群落状况

为了探究三峡工程建成运行后洞庭湖区洲滩生境中小型兽类的群落状况,对洞庭湖区洲滩生境的小型兽类进行调查。调查采用铗日法,于2010至2018年,对洞庭湖区洲滩小型兽类群落的多样性进行了调查,并计算优势度、群落多样性指数、均匀性指数。对多样性指数采用t值法进行比较,各年份、生境的捕获率及鼠种组成差异则采用卡方检验。2010至2018年,共布放34 116铗日,捕获可以分辨种类的样本2 129只,主要有啮齿目(Rodentia)和鼩形目(Soricomorpha)2类,共7种,分别是啮齿目的东方田鼠(Microtus fortis)、黑线姬鼠(Apodemus agrarius)、褐家鼠(Rattus norvegicus)、巢鼠(Micromys minutes)、社鼠(Niviventer confucianus)、黄毛鼠(R. losea)和鼩形目的臭鼩(Suncus murinus)。总捕获率为6.36%,东方田鼠、黑线姬鼠捕获率较高,分别为1.83%、3.94%。从小型兽类组成看,黑线姬鼠和东方田鼠在群落中组成的比例较高,分别为63.18%和29.26%。在调查的5类生境中,植被组成以苔草(Carex sp.)、南荻(Miscanthus sp.)和美洲黑杨(Populus deltoides)为主的生境小型兽类群落多样性指数(1.0772)和均匀度指数(0.6662)均最大,其次是以苔草为主的生境(多样性指数和均匀度指数分别为0.9275、0.5723)、以南荻为主的生境(多样性指数和均匀度指数分别为0.8856、0.550 2)和以苔草加南荻为主的生境(多样性指数和均匀度指数分别为0.775 6、0.481 9),以美洲黑杨为主的生境多样性指数(0.323 6)和均匀度指数(0.180 6)最低,但其优势度最高,为0.881 2。结果表明,随着三峡工程的运行,洞庭湖区植被演替发生了变化,从而引起小型兽类群落动态的变化。在洞庭湖洲滩上,生境越复杂,小型兽类物种多样性越高。单一生境下,人类活动干扰程度越大,小型兽类物种多样性越低。目前,黑线姬鼠已经成为洞庭湖洲滩生境的第一优势鼠种。