共查询到20条相似文献，搜索用时 0 毫秒
1.
《African Journal of Aquatic Science》2013,38(3):337-340
A sampling method and apparatus for collecting meaningful and quantifiable samples of aquatic macroinvertebrates, and the macrophytes they are associated with, are presented. Where physical danger from wildlife is a significant factor, especially in Africa, this apparatus offers some safety in that it can be operated from a boat. The study aimed to determine whether the methods and apparatus presented would sample a similar diversity and abundance of macroinvertebrates in comparison with a standard method. A total of 18 aquatic invertebrate families were collected, with no significant differences in diversity between the methods but, using the proposed method, there were significantly higher abundances of Baetidae, Caenidae, Ecnomidae and Physidae. The methods presented do give a quantifiable sample of macroinvertebrates on submerged macrophytes. 相似文献
2.
Depin Li Myung‐Bok Lee Wen Xiao Jia Tang Zhengwang Zhang 《Ecology and evolution》2020,10(12):5815-5828
Farmland birds are of conservation concerns around the world. In China, conservation management has focused primarily on natural habitats, whereas little attention has been given to agricultural landscapes. Although agricultural land use is intensive in China, environmental heterogeneity can be highly variable in some regions due to variations in crop and noncrop elements within a landscape. We examined how noncrop heterogeneity, crop heterogeneity, and noncrop features (noncrop vegetation and water body such as open water) influenced species richness and abundance of all birds as well as three functional groups (woodland species, agricultural land species, and agricultural wetland species) in the paddy‐dominated landscapes of Erhai water basin situated in northwest Yunnan, China. Birds, crop, and noncrop vegetation surveys in twenty 1 km × 1 km landscape plots were conducted during the winter season (from 2014 to 2015). The results revealed that bird community compositions were best explained by amounts of noncrop vegetation and compositional heterogeneity of noncrop habitat (Shannon–Wiener index). Both variables also had a positive effect on richness and abundance of woodland species. Richness of agricultural wetland species increased with increasing areas of water bodies within the landscape plot. Richness of total species was also greater in the landscapes characterized by larger areas of water bodies, high proportion of noncrop vegetation, high compositional heterogeneity of noncrop habitat, or small field patches (high crop configurational heterogeneity). Crop compositional heterogeneity did not show significant effects neither on the whole community (all birds) nor on any of the three functional groups considered. These findings suggest that total bird diversity and some functional groups, especially woodland species, would benefit from increases in the proportion of noncrop features such as woody vegetation and water bodies as well as compositional heterogeneity of noncrop features within landscape. 相似文献
3.
Mbeng Donatus Waghiiwimbom Bakwo Fils Eric-Moise Atagana Patrick Jules Tsague Kenfack Joseph Aimé Joseph Lebel Tamesse 《African Journal of Ecology》2020,58(2):211-226
In this survey, we investigated the diversity and community structure of bats in the Centre Region of Cameroon with respect to their distribution in the different vegetation zones of the region. We mist-netted bats monthly from January 2016 to June 2017 for five nonconsecutive nights per month. Thirty-nine sites were surveyed: 24 in traditional farms, nine in the savannah and six in the forests. A total of 668 bats were captured during 81 nights of capture, covering seven families, 21 genera and 36 species. This included 26 species in traditional farms, 13 species in savannah and 11 species in the forest. Micropteropus pusillus was the most abundant species (30.7%) recorded, followed by Hipposideros ruber (24.9%). The sample efficiency was estimated at 72.1% with fitted species accumulation curves not reaching asymptotes for the three habitat types, suggesting that the survey did not record all the bats present. There was an indication of general increased in abundance of bats during the dry and rainy seasons but it is not significant (Mann–Whitney U: 783.5, p = .195). The rarity index was highest in traditional farms (0.44), followed by savannah (0.38) and then forest (0.33). This preliminary survey provides baseline data on the distribution of bats in the different vegetation types in the Centre Region of Cameroon. 相似文献
4.
边缘效应与生物多样性 总被引：31，自引：0，他引：31
自从边缘效应提出以来,许多生态学家对它与生物多样性之间的关系进行了研究。大量的事实显示出边缘效应会表现出正效应或负效应,其结果并不完全一致。边缘效应的利用、管理和生物多样性保护是一项有意义而紧迫的工作。 相似文献
5.
Maia Tsurumi 《Global Ecology and Biogeography》2003,12(3):181-190
Aim To describe patterns of hydrothermal vent community diversity and dispersion at the intersegment scale (> 100 km). Location The area discussed is an approximately 170 km portion of the Juan de Fuca Ridge, a mid‐ocean ridge in the north‐east Pacific Ocean. Methods Samples of benthic invertebrates from hydrothermal vents on three segments of the Juan de Fuca are examined for community characteristics such as diversity, abundance and distribution. Results Species richness (55 species) and evenness are low. If the macrofauna only are considered, species richness is about 30% lower than when meiofauna are also considered. The geometric series describes the species‐abundance distribution. The relationship between vent species’ distribution and abundance is significantly positive (r2 = 0.818; P < 0.001). Alpha diversity is lower in patchy habitat than continuous habitat and gamma diversity is similar for both habitat types. Beta diversity is higher in patchy habitat. Local diversity is linearly related to regional diversity. Main conclusions Species richness is comparable to other highly disturbed systems. The geometric series species abundance model implies some degree of niche pre‐emption in the vent community and is consistent with the suggestion that the geometric series distribution can be found in species‐poor environments that experience harsh conditions and are structured by relatively few environmental factors. Species distribution and abundance are highly correlated. The regional species pool affects local vent diversity. Vent diversity studies should be conducted on at least the ridge scale. 相似文献
6.
Koen J. J. Kuipers Sarah Sim Jelle P. Hilbers Stefanie K. van den Berg Melinda M. J. de Jonge Krista Trendafilova Mark A. J. Huijbregts Aafke M. Schipper 《Global Change Biology》2023,29(22):6234-6247
Land use is a major cause of biodiversity decline worldwide. Agricultural and forestry diversification measures, such as the inclusion of natural elements or diversified crop types, may reduce impacts on biodiversity. However, the extent to which such measures may compensate for the negative impacts of land use remains unknown. To fill that gap, we synthesised data from 99 studies that recorded mammal populations or assemblages in natural reference sites and in cropland and forest plantations, with or without diversification measures. We quantified the responses to diversification measures based on individual species abundance, species richness and assemblage intactness as quantified by the mean species abundance indicator. In cropland with natural elements, mammal species abundance and richness were, on average, similar to natural conditions, while in cropland without natural elements they were reduced by 28% and 34%, respectively. We found that mammal species richness was comparable between diversified forest plantations and natural reference sites, and 32% lower in plantations without natural elements. In both cropland and plantations, assemblage intactness was reduced compared with natural reference conditions, but the reduction was smaller if diversification measures were in place. In addition, we found that responses to land use were modified by species traits and environmental context. While habitat specialist populations were reduced in cropland without diversification and in forest plantations, habitat generalists benefited. Furthermore, assemblages were impacted more by land use in tropical regions and landscapes containing a larger share of (semi)natural habitat compared with temperate regions and more converted landscapes. Given that mammal assemblage intactness is reduced also when diversification measures are in place, special attention should be directed to species that suffer from land use impacts. That said, our results suggest potential for reconciling land use and mammal conservation, provided that the diversification measures do not compromise yield. 相似文献
7.
Werner Ulrich Buntarou Kusumoto Simone Fattorini Yasuhiro Kubota 《Diversity & distributions》2020,26(6):769-778
8.
大别山地区虫生真菌群落结构与生态分布 总被引：12，自引：0，他引：12
本文对安徽大别山地区虫生真菌的群落结构和生态分布规律进行了研究。在天堂寨和鹞落坪2个自然保护区共设样方278个,先后采集罹病标本1986个,共计50种,隶属于4目、4科、16属。优势种依次为粉拟青霉、细脚拟青霉、下垂虫草、球孢白僵菌和金龟子绿僵菌。在垂直分布上,种的丰度、多度和物种多样性指数都以海拔1100-1150m最高,随着海拔升高或降低,各多样性指标基本上表现递减的趋势。季节分布上,夏季是虫生真菌物种分布最丰富的季节,随着温度下降和雨量的减少,种的丰度和多度也明显下降。另外,该区虫生真菌群落呈现出明显的水平地带性分布规律。 相似文献
9.
甘肃麦积山风景区熊蜂物种多样性调查 总被引：1，自引：0，他引：1
熊蜂属昆虫是山区植物的重要传粉者,在保持生物多样性和维护生态系统平衡方面发挥着十分重要的作用。麦积山风景区位于甘肃东南部的西秦岭山区,地处北部温带黄土高原向南部亚热带河谷山地和西部高寒青藏高原过渡的地带,地理位置独特,生物资源丰富。为了探明该景区内熊蜂物种多样性现状,笔者于2007—2010连续4年对该景区的熊蜂属昆虫进行了系统调查。结果表明:2007—2010年,在该景区12个采样点共采集熊蜂属昆虫1 765头,隶属于7亚属20种;在12个采样点中,石门和净土寺的熊蜂种类丰富度最高;在20种熊蜂中,火红熊蜂Bombus pyrosoma、红光熊蜂B.ignitus、疏熊蜂B.remotus、小峰熊蜂B.hypocrita s.l.和重黄熊蜂B.picipes的物种多度较高,依次位居前5位;麦积山风景区熊蜂区系成分以东洋区+古北区共有种为主(55%),其中东洋区成分高于古北区成分;麦积山熊蜂区系成分和南部亚热带湿润气候区的白水江自然保护区以及西部高寒气候区的扎尕那自然保护区比较接近,和北部温带半干旱气候区的崆峒山风景区相距较远。 相似文献
10.
生物多样性与生态系统功能:进展与争论 总被引：50，自引：4，他引：50
生物多样性与生态系统功能的关系已成为当前人类社会面临的一个重大科学问题,生物多样性的空前丧失,促使人们开展了大量研究工作来描述物种多样性-生态系统功能关系,并试图揭示多样性与系统功能关系的内在机制,本文将多样性对生态系统功能作用机制的有关假说分为统计学与生物学两大类：前者是从统计学角度来解释观察到的多样性-系统功能模式,包括抽样效应,统计均衡效应等;而后者是基于多样性的生物学效应给出的,包括生态位互补,种间正相互作用,保险效应等,本文较为详细地介绍了该领域内有代表性的实验工作,包括“生态箱”实验,Cedar Creek草地多样性实验,微宇宙实验,欧洲草地实验,以及在这些实验结果解释上的激烈争论。 相似文献
11.
1. The ciliate and metazoan meiofaunal assemblages of two contrasting lowland streams in south‐east England were examined over the period of a year, using a high taxonomic resolution. Monthly samples were taken from an oligotrophic, acid stream (Lone Oak) and a circumneutral, nutrient‐rich stream (Pant) between March 2003 and February 2004. 2. We assessed the relative importance of ciliates and rotifers within the small‐sized benthic assemblage with respect to their abundance, biomass and species richness. In addition, we examined the influence of abiotic and biotic parameters and season on the assemblage composition at two levels of taxonomic resolution (species and groups). 3. Ciliates dominated the assemblages numerically, with maximum densities of over 900 000 and 6 000 000 ind. m?2 in Lone Oak and Pant respectively. Rotifers and nematodes dominated meiofaunal densities, although their contribution to total meiofaunal biomass (maxima of 71.9 mgC m?2 in Lone Oak and of 646.8 mgC m?2 in the Pant) was low and rotifer biomass equalled that of ciliates. 4. Although the two streams differed in terms of total abundance of ciliates and meiofauna and shared only 7% of species, the relative proportion of groups was similar. Sediment grain size distribution (the percentile representing the 0.5–1 mm fraction) was correlated with assemblage structure at the species level, revealing the tight coupling between these small organisms and their physical environment. Seasonal changes in the relative abundance of groups followed similar patterns in both streams, and were correlated with the abundance of cyclopoid copepods and temperature. 5. Information on these highly abundant but often overlooked faunal groups is essential for estimates of overall abundance, biomass, species richness and productivity in the benthos, and as such has important implications for several areas of aquatic research, e.g. for those dealing with trophic dynamics. 相似文献
12.
The total number of insect species in the world is an important if elusive figure. We use a fresh approach to estimate global insect species richness, based on biogeographic patterns of diversity of well or better documented taxa. Estimates generated by various calculations, all variations on a theme, largely serve to substantiate suggestions that insect species are likely to number around 10 million or less. 相似文献
13.
农田生物多样性评价中常采用指示类群基于物种鉴定水平的数据计算多样性指数,如果能用高级别的分类鉴定结果(如科)或直接用该指示类群个体数来代替该类群物种水平上的多样性指数,可以极大地节省鉴定的成本和降低鉴定难度。同时采用多个指示类群田间取样数据和多种分析方法验证这个问题有助于获得更为普适的结论。为研究农田节肢动物不同分类级别和个体数对于物种丰富度的替代效果,于2019年5-8月在浙江省宁波市的两片不同管理措施和多生境的农田景观区进行了节肢动物群取样调查,并对蜘蛛和蜂类两个类群进行了科级和物种级别的鉴定。通过分析目级和科级分类水平的数目、指示类群的个体数与物种丰富度之间的相关性;并基于这4个指数进行不同管理措施和生境间的双因素方差分析;同时基于目级、科级和物种级别数据,采用非度量多维尺度分析(NMDS)对比他们在不同管理措施和生境间的种类组成差异。结果显示:(1)将蜘蛛、蜂类分类至科级可分别拟合其物种水平数据63%和89%的变异性,并且比目级的数据相关性更大。(2)两个指示类群的个体数与物种数之间都有极为显著的相关性,且r≥0.7。(3)比起目级数,科级数和个体数在不同管理措施和生境间的差异结果和物种数更类似。(4)基于分科数据的NMDS在不同管理措施和生境间差异的结果也和物种级别数据的结果更类似。因此,在农田生物多样性的评估中,可以在一定程度上采用较高层次分类的数据,其中科级水平的数据作为首选,从而降低分类鉴定难度并提高工作效率。在需要快速进行蜘蛛和蜂类等基于大量标本数目的生物多样性评估时,可直接统计指示类群个体数量来替代物种数结果。 相似文献
14.
Péter Batáry Kornélia Kurucz Marcela Suarez‐Rubio Dan E. Chamberlain 《Global Change Biology》2018,24(3):1046-1054
Urbanization is one of the most extreme forms of environmental alteration, posing a major threat to biodiversity. We studied the effects of urbanization on avian communities via a systematic review using hierarchical and categorical meta‐analyses. Altogether, we found 42 observations from 37 case studies for species richness and 23 observations from 20 case studies for abundance. Urbanization had an overall strong negative effect on bird species richness, whereas abundance increased marginally with urbanization. There was no evidence that city size played a role in influencing the relationship between urbanization and either species richness or abundance. Studies that examined long gradients (i.e. from urban to rural) were more likely to detect negative urbanization effects on species richness than studies that considered short gradients (i.e. urban vs. suburban or urban vs. rural areas). In contrast, we found little evidence that the effect of urbanization on abundance was influenced by gradient length. Effects of urbanization on species richness were more negative for studies including public green spaces (parks and other amenity areas) in the sampled landscapes. In contrast, studies performed solely in the urban matrix (i.e. no green spaces) revealed a strong positive effect on bird abundance. When performing subset analyses on urban–suburban, suburban–rural and suburban–natural comparisons, species richness decreased from natural to urban areas, but with a stronger decrease at the urban–suburban interface, whereas bird abundance showed a clear intermediate peak along the urban–rural gradient although abundance in natural areas was comparable to that in suburban areas. This suggests that species loss happens especially at the urban–suburban interface, and that the highest abundances occur in suburban areas compared to urban or rural areas. Thus, our study shows the importance of suburban areas, where the majority of birds occur with fairly high species richness. 相似文献
15.
16.
- Odonates are an ancient group of freshwater invertebrates that have complex life cycles and highly variable phenotypes and behaviours. These traits make odonates a very attractive model group to study various aspects and phenomena in the fields of ecology, behaviour, and evolutionary biology.
- Such variability in appearance and behaviour can influence the detectability of individual species under natural conditions; and this variability in detection rates, if not statistically treated, may lead to significant distortions of results and misleading conclusions.
- In the present study, we used detectability models to predict the time to detection (TTD) of individual odonate species and generalised linear mixed models to analyse the effects of morphological and behavioural traits on the TTD of the first individual of a species.
- We found that only abundance had a significant effect on the TTD of both Anisoptera and Zygoptera, while the larger Anisoptera were generally detected earlier. No such patterns were observed in Zygoptera; however, dispersal ability was found to have had some influence.
- Surprisingly, coloration and activity were not found to influence the TTD of odonates. Therefore, although there are considerable differences between species, with the exception of abundance and size, we did not detect any easily measurable traits that would unequivocally explain the differences in the detection rates of individual species.
17.
生物多样性与生产力的关系是当前生态学中研究的重点之一,以呼伦贝尔草原为研究对象,通过连续两个生长季的野外监测,从草地植物功能型的角度探讨了在不同利用方式下草地物种丰富度与地上生物量的关系,结果表明：（1）不同草地利用方式显著影响草地生物多样性和生产力,在3种不同利用方式中,生物多样性总体的趋势是割草〉围封〉放牧,其中Shannon-Wiener指数、Simpson指数和物种丰富度均差异显著;割草草地地上生物量最高,围封草地次之,放牧草地最少。（2）将草地植物按照植物功能型分类,放牧草地1、2年生植物占优势,随着物种丰富度的增加,1、2年生植物生物量没有明显的变化趋势;割草草地以禾本科植物和非禾本科植物为主,随着物种丰富度的增加,禾本科植物生物量呈下降趋势,而非禾本科植物变化不明显;围封草地中禾本科植物占优势,其他功能型植物分布较均匀,多度、频度和生物量等差异不显著。（3）3种草地利用方式中只有围封草地物种丰富度和地上生物量存在显著的正相关,即随着物种丰富度的增加,生物量也随之升高。其他两种利用方式下,物种丰富度对地上生物量没有显著影响。 相似文献
18.
Besma Haffaressas Sihem Djellab Farrah Samraoui Ahmed H Alfarhan Francis Gilbert Antonio Ricarte 《法国昆虫学会纪事》2013,49(5):324-333
A survey of the hoverflies (Diptera: Syrphidae) of the region of Guelma, northeast Algeria, was carried out from August 2011 to July 2013. A total of 31 species was recorded with six (Scaeva mecogramma, Epistrophe melanostoma, Syrphus vitripennis, Brachypalpus valgus, Merodon calcaratus and M. chalybeus) new to Algeria. Of these, three species (E. melanostoma, M. calcaratus and M. chalybeus) are also new additions to the entomofauna of North Africa. The results complement those of a previous study covering Numidia and Tebessa and provide a more comprehensive view of the phenology and distribution of Syrphidae across northeast Algeria. An improved knowledge of the distribution of North African hoverflies will contribute to a better assessment of the status of each taxon and inform conservation efforts. 相似文献
19.
以数据为支撑的物种多样性空间分布是自然保护地适应性保护和管理的基础, 但当前大多数自然保护地缺乏全域物种多样性观测数据。本研究以钱江源国家公园全域663个20 m × 20 m木本植物样方调查数据为基础, 分析了国家公园内观测物种丰富度、稀疏物种丰富度、胸高断面积和树木个体数量的空间变化, 比较了这些变量在国家公园各功能区块间的差异。结果显示木本植物物种多样性的热点分布区与钱江源国家公园核心保护区基本匹配。两个物种丰富度在核心保护区古田山区块和长何齐区块及一般控制区古田-苏庄区块最大, 三者的观测物种丰富度无显著差异(P > 0.05), 古田山区块和古田-苏庄区块的稀疏物种丰富度无显著差异, 但均显著大于长何齐区块; 古田山区块和古田-苏庄区块的两个物种丰富度指标变异程度小于其他区块, 且这两个区块间无显著差异(P > 0.05)。齐溪区块、长何齐区块和古田山区块胸高断面积大于其他区块, 古田-苏庄区块次之, 前三者无显著差异, 古田-苏庄区块显著小于长何齐区块和古田山区块。古田山区块和古田-苏庄区块树木个体数量最小。长何齐区块齐溪片区部分胸高断面积大、个体数量小, 而在长虹和何田片区胸高断面积小、个体数量大。一般控制区长虹-何田区块和古田-洪源区块两个物种丰富度最小, 胸高断面积最小。结果表明, 从生物多样性角度来看钱江源国家公园的功能分区基本合理, 扩展了对国家公园物种多样性热点和保护空缺的认识: 古田山区块木本植物个体大、物种最丰富, 与其毗邻的一般控制区古田-苏庄区块物种同样丰富、个体略小, 可将其纳入保护核心区以利于钱江源国家公园主要生态系统完整性保护; 核心保护区长何齐区块长虹和何田片区物种多样性低、个体小、密度大, 待加强保护和修复; 长虹-何田区块和古田-洪源区块物种少、个体小、干扰强, 待社区发展和保护协同。本研究将为钱江源国家公园生物多样性适应性保护和管理提供科学支撑。 相似文献
20.
The spatial scale and density‐dependent effects of non‐native brown trout Salmo trutta on species richness of fish assemblages were examined at 48 study sites in Mamachi Stream, a tributary of Chitose River, Hokkaido, Japan. The density of age ≥1 year S. trutta was high in the upstream side of the main stem of Mamachi Stream. Fish species richness increased with increasing area of study sites (habitat size), but the increasing magnitude of the species richness with area decreased with increasing age of ≥1 year S. trutta density. The relationships between age ≥1 year S. trutta, however, and presence–absence of each species seemed to be different among species. Species richness was also determined by location and physical environmental variables, i.e. it was high on the downstream side and in structurally complex environments. 相似文献