西沙群岛主要岛屿鸟类和小型兽类群落调查研究

对海岛动物资源的本底调查和研究,可为更好地保护海洋和海岛生态系统提供重要的依据。2018年4月-2019年12月,利用样线法、铗夜法等对西沙群岛东岛、永兴岛等岛屿的鸟类、小型兽类资源进行了4次调查,结合历史记录数据对其物种组成和多样性变化进行了分析。调查共记录到小型兽类3种,臭鼩（Suncus murinus）见于林灌丛,褐家鼠（Rattus norvegicus）和黄胸鼠（R.flavipectus）见于房舍区;共记录到鸟类13目26科65种,其中国家Ⅱ级重点保护动物4种,新记录到鸟类29种;广布型鸟类34种,古北界鸟类20种,东洋界鸟类11种;冬候鸟28种,留鸟23种,旅鸟6种,夏候鸟5种,迷鸟3种;东岛鸟类物种数高于永兴岛,但多样性和均匀度均较低;雨季物种丰富度、多样性和均匀度均高于旱季;东岛为国家Ⅱ级重点保护动物红脚鲣鸟（Sula sula）中国唯一的繁殖地,应加强保护。与1974年和2005年报道的数据对比,本次调查记录的鸟类物种丰富度最高,留鸟物种数最多。结果反映西沙群岛小型兽类种类较少,主要分布在房舍区及其附近的林灌从;暗示小型兽类带入、扩散等可能与人为活动相关,其生态效应予以重视和长期监测。西沙群岛鸟类物种有丰富度较高、候鸟占比高、季节和年份间差异明显、留鸟物种数有所增加、为红脚鲣鸟唯一的繁殖地等特点。西沙群岛生态系统的完整性,对候鸟和留鸟的保护,尤其是红脚鲣鸟的保护十分重要,应予以重视。     

Species composition,relative abundance and habitat association of small mammals along the altitudinal gradient of Jiren Mountain,Jimma, Ethiopia

To document the species composition, relative abundance and habitat association of small mammals, wet and dry season surveys were conducted along the altitudinal gradient of Jiren Mountain, Jimma area, Ethiopia. Sherman traps were used to capture small mammals from the six habitats: wetland, mixed plantation, open shrub, eucalyptus plantation, montane grassland and coffee plantation. The 393 trap nights, from the six habitat types, yielded 106 individual small mammals of tweleve species. The trapped rodents were Lophuromys flavopunctatus, Stenocephalemys albipes, Desmomys harringtoni, Mus mahomet, Lemniscomys barbarous, L. striatus, Tachyoryctes splendens, Mastomys natalensis and the insectivores Crocidura fumosa and C. turba. Two species of rodents Hystrix cristata and Helioscuirus gambianus were observed. Lophuromys flavopunctatus and S. albipes contributed 83.8% of the total capture. L. flavopunctatus, S. albipes and D. harringtoni were distributed in all habitats and gradients. T. splendens was captured from montane habitat, while the zebra mice were associated with the lower altitude habitats. Lophuromys flavopunctatus and M. natalensis extended their range deep into the coffee plantation habitats. Uncontrolled vegetation exploitation of the mountains for timber production and fire wood collection are the major threats. Conservation of the area to reduce the anthropogenic pressure is essential.     

小兴安岭林区不同生境梯度中小型哺乳动物生物多样性

利用铗日法和陷阱法,于2000年7～8月,对小兴安岭林区7个不同生境梯度中小型哺乳动物群落的多样性变化进行了初步研究。结果表明：(1)铗日法所捕获的物种数和个体数明显大于陷阱法．但后者更适合捕获小体型动物;(2)共捕获小型哺乳动物9种．其中啮齿目(Rodentia)松鼠科(Sciuridae)1种．田鼠亚科(Microtine)3种．鼠科(Muridae)4种．食虫目(Insectivora)鼩鲭科(Soricidae)1种．所捕获的物种中．棕背解(Clethrionomys rufocanus)为优势种．占总数的48．77％．与黑线姬鼠(Apodemus agrarius )、大林姬鼠(A．speciosus)和红背Ping(C．rutilus)一起构成本地区的常见种;(3)物种在不同的生境类型中呈明显的不均匀分布．以中度干扰的灌丛生境内小型哺乳动物从物种丰富度和多样性指数最高．次生林1和农田生境均有较高的物种丰富度和多样性指数,无干扰的原生林1、2中物种丰富度最低,而轻微干扰的原生林3中物种多样性指数最低．受严重干扰的农田生境中小型哺乳动物均匀度最高．其次是次生林1和灌丛,原生林3和干扰较重的次生林2中小型哺乳动物群落均匀度最小;(4)从物种多样性与林地郁闭度和地表草本植物覆盖度的相关分析看出：物种多样性与郁闭度相关性不显著．而与覆盖度呈显著的正相关关系．反映了这些物种对草本植物选择倾向;(5)根据不同生境内群落相似性指数进行系统聚类,将所有的生境聚类为3组．即原生林组(原生林1、原生林2和原生林3)、次生林组(次生林1和次生林2)和农田组(灌丛和农田)．表明组内各生境间小型哺乳动物成分的相似性和组间的明显差异。研究表明．小型哺乳动物多样性受生境内植被演替阶段、食物和隐蔽条件等环境因素影响．而人类干扰也是主要因素之一。     

Interspecific abundance–occupancy relationships of British mammals and birds: is it possible to explain the residual variation?

Aim The majority of studies concerning positive interspecific abundance–occupancy relationships have used broad‐scale and microcosm data to test the occurrence and correlates of the relationship to determine which of the proposed mechanisms give rise to it. It has been argued recently that studying the residual variation about abundance–occupancy relationships is a more logical analysis and may yield faster progress in identifying the relative roles of the mechanisms. However, to date this approach has been largely unsuccessful. Here we test if fundamental species traits such as the status (native and introduced), habitat and trophic group of mammal and bird species may explain any of the residual variation about their respective abundance–occupancy relationships. Location The study used British mammal and bird species. Methods We tested if species traits explained any of the variation about abundance–occupancy relationships using linear regression techniques both treating species as independent data points for analysis and controlling for phylogenetic association. Results None of the species traits could explain any residual variation about the positive interspecific abundance–occupancy relationships of British mammals and birds. This applied both when treating species as independent data points and after controlling for phylogenetic association. Conclusions Given the lack of explanatory power of the species traits here and in other studies using this approach it seems that the variation about positive interspecific abundance–occupancy relationships is not explicable in a simple fashion. Predicting the likely influence of traits that are independent of phylogeny is also problematic. Therefore, the general utility of this approach and its future role in understanding the mechanisms causing positive interspecific abundance–occupancy relationships is doubtful.     

The responses of small mammals to patches regenerating after fire and rainfall in the Simpson Desert,central Australia

Abstract Patch‐burning is frequently advocated as a management tool to enhance the biodiversity and pasture values of spinifex (Triodia) grasslands. In this study we compare the capture rates of small mammals in habitats regenerating shortly after fire (aged 1–5 years) and in long‐unburnt habitats (aged >25 years). To unravel the effects of temporally and spatially variable rainfall on capture rates, the study was replicated at three locations spaced over 50 km apart that experience different rainfall regimes. Ten species of small mammals were captured over the course of the study, between October 1999 and June 2001. Pseudomys desertor showed a strong preference for long‐unburnt habitats. Notomys alexis, Sminthopsis youngsoni and Sminthopsis hirtipes showed some preferences for regenerating habitats, but these were not consistent throughout the study. Factors indicative of temporal and spatial variation in rainfall, time and site had important effects on capture rates. High rainfalls associated with the La Niña phase of the El Niño/Southern Oscillation in 2000 increased seed production and prompted eruptions of rodent species and the carnivorous Dasycercus cristicauda. The greatest numbers of captures were made at the sites that received the highest rainfalls. We conclude that patch‐burning regimes do not benefit small mammals directly, but are likely to increase the resilience of ‘fire‐sensitive’ species that are dependent on dense spinifex by reducing the extent of wildfires.     

BIODIVERSITY RESEARCH: Nestedness for different reasons: the distributions of birds,lizards and small mammals on islands of an inundated lake

Aim We examined whether the community compositions of birds, lizards and small mammals were nested in a fragmented landscape in the Thousand Island Lake, China. We also assessed whether the mechanisms influencing nestedness differed among these taxonomic groups. Location Thousand Island Lake, China. Methods Presence/absence matrices were compiled for birds (42 islands) and lizards (42 islands) using line‐transect methods, and for small mammals (14 islands) using live‐trapping methods from 2006 to 2009. Nestedness was analysed using BINMATNEST, and statistical significance was assessed using the conservative null model 3. We used Spearman rank correlations and partial Spearman rank correlations to examine associations of nestedness and habitat variables (area, isolation, habitat diversity and plant richness) as well as life‐history traits (body size, habitat specificity, geographical range size and area requirement) related to species extinction and immigration tendencies. Results The community compositions of birds, lizards and small mammals were all significantly nested, but the causal factors underlying nestedness differed among taxonomic groups. For birds, island area, habitat specificity and area requirement were significantly correlated with nestedness after controlling for other independent variables. For lizards, habitat heterogeneity was the single best correlate of nestedness. For small mammals, island area, habitat heterogeneity and habitat specificity were significantly correlated with nestedness. The nested patterns of birds, lizards and small mammals were not attributable to passive sampling or selective colonization. Main conclusions The processes influencing nested patterns differed among taxonomic groups. Nestedness of bird assemblages was driven by selective extinction, and lizard assemblage was caused by habitat nestedness, while nestedness of small mammals resulted from both selective extinction and habitat nestedness. Therefore, we should take taxonomic differences into account when analysing nestedness to develop conservation guidelines and refrain from using single taxa as surrogates for others.     

Effects of roads on small mammal diversity and abundance in the northern Serengeti,Tanzania

The high biodiversity of small mammal species in the Serengeti ecosystem provides this ecosystem with important conservation value. However, whether the extensive development of roads has negative impacts on the small mammal population has not been tested. Small mammal population diversity and abundance were examined in this study using live trapping at sites close to (experimental) and away (control) from the main gravel road during the short rainy seasons in November and December 2011 and 2012. A total of 138 individuals from three orders representing six families and fourteen species were collected over 4,860 trap nights. There were no significant differences in the species richness, diversity or abundance of small mammals between the control and experimental sites (p > 0.05), suggesting that the current gravel road does not have a significant impact on the small mammal population. These findings were ascribed to the availability of favourable habitats at both distances as a result of little road usage due to poor conditions. Should the road be improved, the control of anthropogenic activities in the area should be given high priority. Continuous monitoring of the small mammal populations in the area is recommended.     

Notes on the vegetation of the Bougainville Peninsula,Osborn and Institut Islands,North Kimberley District,Western Australia

The Bougainville Peninsula is formed of basalt capped with mesaform remnants of a bauxitic duricrust. On the plateau so formed there is little soil and the vegetation comprises scattered stunted eucalypts with grasses and hummock grasses or an understorey of Acacia and other shrubs. Locally there are patches of woodland of Eucalyptus nesophila and E. miniata. On the basalt country below the plateau there is deciduous vine thicket in the less accessible parts, a patchy mixture of vine thicket and savanna elsewhere including communities of vine thicket with scattered emergent eucalypts. The Osborn Islands are similar except that the mesaform capping is generally of sandstone. It is concluded that fire is the principal factor regulating the balance between vine thicket and savanna. Up to 40 years ago the area was populated by aborigines and regularly burnt off but this has now ceased so that colonisation by vine thicket is in progress, in spite of the low rainfall of the area.These authors are indebted to the Amax Exploration Company for providing helicopter transport to the localities concerned and for approval to publish this paper: also to the staff of the Western Australian Herbarium, Mr M. I. Brooker, Mr J. Macorochie and Dr V. Semeniuk for the identification of botanical specimens.This author is indebted to the Department of Defence (Navy Office) for permission to join a naval patrol boat. The assistance of Lieutenants J. Wells, R. Gates and the crew of HMAS Attack is gratefully acknowledged. The co-operation of Mr T. P. Farrell (CRA Services) and the Mitchell Plateau Bauxite Company for providing helicopter transport is also appreciated.     

甘肃河西小型哺乳动物物种多样性与水热分布的关系

野外调查、文献和标本资料收集相结合,采用因子分析法,分析了甘肃河西地区小型哺乳动物物种多样性分布格局与水热条件空间分布的关系.结果表明:物种丰富度与年降水量呈正相关关系,而与最热月(7月)平均温度、年平均温度、年蒸发量呈负相关关系,与最冷月(1月)平均温度相关性不明显;影响小型哺乳动物物种丰富度空间分布的决定因素以年降水量、最热月(7月)平均温度、年平均温度、年蒸发量为主的要素所构成的基本景观因子,其次是最冷月(1月)平均温度.     

The effects of fragmentation and disturbance of rainforest on ground-dwelling small mammals on the Robertson Plateau, New South Wales, Australia

We surveyed ground-dwelling small mammals in twenty-four rainforest remnants which were virtual islands surrounded by farmland on a plateau on the east coast of Australia. We investigated the effect of island size, level of disturbance, isolation and microhabitat on the abundance and species richness of the mammals. The remnants ranged from 0.3 to 29 ha, resulting from fragmentation during 175 years of European occupation. Two rodent species (Rattus fuscipes[Waterhouse, 1839] and R. rattus[Linnaeus, 1758] ) and one marsupial insectivore (Antechinus stuartii Macleay, 1841) were trapped in these remnants, with an additional species (A. swainsonii[Waterhouse, 1840] ) several kilometres away in rainforest on the escarpment of the plateau. Small-mammal species richness was low, but the native species (R. fuscipes and A. stuartii) were abundant. Three-way analyses of variance demonstrated that species richness and abundance decreased significantly with decreasing remnant size and increasing disturbance, but showed no distance effect. The abundance and richness of native species responded even more significantly. The interaction between the first two effects is important. Small remnants are affected most detrimentally by increasing disturbance, large remnants are less affected, and medium sized remnants show intermediate effects. The introduced R. rattus which was least abundant in large remnants, but more abundant in distant than near remnants, was also more abundant in those with major disturbance. The single most important variable in step-wise, multiple linear regression analyses was the logarithm of remnant area not influenced by edge effects, explaining 39% of the variance in species richness, 57% for native species richness and 46% for A. stuartii abundance. Disturbance related variables additionally contributed from 12 to 30% of the variance in dependent variables, while habitat variables explained between 22 and 48% of the variance, and accounted for two thirds of the explainable variance in R. fuscipes abundance. The implications of our results for wildlife conservation on the plateau are discussed.     

Biological control of the weed,Chromolaena odorata [Asteraceae], byPareuchaetes pseudoinsulata [Lep.: Arctiidae] on Guam and the northern Mariana Islands

Chromolaena odorata L. is a major weed of tropical plantations and pasture lands.Pareuchaetes pseudoinsulata Rego Barros [Lep.: Arctiidae] was mass-reared and released to control the weed on the Mariana Islands of Guam, Rota, Tinian and Saipan in the western Pacific. One year following establishment ofP. pseudoinsulata on Guam, the weed was reduced 100% at 3 of 4 sites monitored with fixed quadrats. Seed production was prevented if defoliation occurred prior to the beginning of the flowering season. If defoliation occurred shortly after flowering began, the developing seeds were eaten byP. pseudoinsulata or there was a significant reduction in weight and germination of seeds that matured. Eighteen months after establishing on Guam,P. pseudoinsulata had defoliated approximately 25,000 hectares of the weed. This is the 1^st report on the quantitative impact of any control agent forC. odorata, and though the long term effect of the insect is still unknown, these results are encouraging.