Species number, species abundance and body length of arboreal arthropods associated with an Australian rainforest tree

Abstract.

• 1 The species number, the abundance per species and the body length of arthropods foraging within the crowns of an over-storey rainforest tree from Australia, Argyrodendron actinophyllum (Sterculiaceae), were investigated by interception trap sampling and restricted canopy fogging. Emphasis was placed upon the interpretation of trap data. Arthropods were trapped continuously day and night, over a 2-year period and the final analyses examined the attributes of 759 species which represented 20,500 individuals.
• 2 The proportion of‘rare’species (Le. collected once) intercepted was high (35.7%), although lower than in other similar rainforest surveys. Neither the α log-series nor the log-normal distribution could be fitted to the relationship between number of species and number of individuals, since the number of rare species was much higher than predicted and the mode of the distribution could not be identified. The proportion of rare species was higher in fogging collections (452%) than in trap collections.
• 3 The data are compared with a study of Bornean arboreal beetles, obtained by fogging trees during a single sampling event. Several patterns were common to both data sets. However, the three-dimensional plot of the variables describing the structure of the arthropod community showed a notably rougher surface than in the case of Bornean beetles.
• 4 Although several factors may complicate the interpretation of the three-dimensional plots, long-term and continuous sampling may alter our perception of complex arthropod communities. This methodology is imperative for a proper understanding of arthropod community structure in rain forests.

     

人工固沙植被恢复对地表节肢动物群落组成及多样性的影响

人工绿洲是干旱区主要的自然景观之一,为了维护绿洲稳定而营建的防护林强烈改变地表生态水文过程,进而影响着地上和地下生物多样性。然而,以往的研究对地上植被关注较多,而对土壤动物研究较少。以张掖绿洲外围人工固沙植被群落和天然固沙植被群落为研究对象,探讨人工固沙植被恢复对荒漠地表节肢动物群落组成及多样性的影响及不同动物类群对植被变化的响应模式。研究表明,天然固沙植被群落转变为人工固沙植被群落显著降低了地表节肢动物数量,但提高了地表节肢动物类群丰富度和多样性,这在5月份表现尤为明显。植被类型对地表节肢动物群落的影响不同,8月人工柽柳林群落地表节肢动物活动密度、类群丰富度和多样性均显著高于人工梭梭林群落。人工固沙植被恢复显著降低了适应荒漠环境的拟步甲科甲虫,而蚁科和部分蜘蛛的数量显著增加,它们对人工固沙植被恢复的响应模式不同决定了群落结构及多样性的变化规律。此外,研究还发现一些地表节肢动物类群对不同生境具有强烈的指示作用,如拟步甲科等可指示荒漠生境,潮虫科等可指示梭梭林生境,而蠼螋科和狼蛛科等可指示柽柳林生境。综上所述,人工栽植固沙灌木形成的固沙植被群落导致了一些适应荒漠环境的地表节肢动物类群的数量降低,但也为更多的地表节肢动物类群提供了适应栖居环境和充足的食物资源等,从而提高了地表节肢动物的多样性。     

鲁南地区花生昆虫群落结构及多样性变化研究

采用马来氏网法在山东省临沂市开展了花生田昆虫系统调查(2014年6月-2015年6月),阐明当地花生田的昆虫群落结构及相关群体指数动态规律。结果表明:试验期内共获得昆虫样本65 005头,分属于14目、129科。从目级水平来看,主要花生昆虫以膜翅目、鞘翅目、半翅目、双翅目和弹尾目为主;从科级水平来看,主要花生害虫有叶蝉科、夜蛾科和潜蝇科,主要天敌有花蝇科、长足虻科、金小蜂科、长蝽科和姬蜂科。该地区群落多样性指数在0.4262～3.3212之间,峰值出现在花生生长期(3.3312);相对丰度峰值出现在花生繁育期(9 956);科级丰富度峰值出现也出现在花生繁育期(83);均匀度指数在0.1137～0.7613之间,峰值出现在2014年6月(0.7613);优势集中指数在0.0172～0.2134之间,峰值出现在2014年8月(0.2134)。     

上海地区葡萄种植园昆虫种群调查

葡萄是上海地区重要的经济水果,为探明上海葡萄种植园中昆虫种群组成,本研究在2017-2018年间,通过搜捕法、马氏网诱集法和黄色粘纸诱集法,对上海市嘉定区、奉贤区、青浦区、浦东新区、崇明岛进行了昆虫种群调查,共采集并鉴定昆虫7目65科123属182种,明确了上海地区葡萄种植园内主要害虫、天敌昆虫及环境昆虫的种类,并对上海葡萄园的昆虫种群结构和多样性进行了分析。     

Duration and frequency of non-flow periods affect the abundance and diversity of stream meiofauna

1. Intermittent streams (IS) comprise a large proportion of the drainage network in many parts of the world. The non-flow period of IS are known to impact stream biota because aquatic habitats dry out. However, less well understood are the relative effects of the temporal component of these drying events including their duration and frequency.
2. Here, we characterised effects of temporal component of drying events on abundant and species-rich meiofauna. The effects were assessed in 22 streams in the north-eastern Iberian Peninsula. The duration and frequency of non-flow events was characterized over a period of 250 days prior to sampling the sediment-dwelling meiofauna in riffle zones that completely dried out.
3. Overall, meiofauna abundances were amongst the highest ever reported for streambeds. Most meiofaunal taxa correlated positively with the frequency of drying events and correlated positively with the length of dry periods recorded shortly before sampling, suggesting that the community was able to recover quickly. Tardigrades were the only group to correlate positively with the longest dry periods, suggesting that they had the best resilience capabilities in streams that had experienced the longest droughts.
4. On average, nematodes made up half of the meiofauna. We identified a total of 113 different nematode species. The nematode community was more taxonomically diverse in IS, with a smaller proportion of bacterivores and a higher proportion of fungivore species such as Filenchus vulgaris. Thereby resembling the trophic structure commonly observed in soil ecosystems.
5. Our results show that most meiofauna were positively influenced by drying disturbance, that is being able to quickly recover after them. This suggests outstanding resilience capabilities, and points out meiofaunal organisms as key players for kick-starting stream food webs and functions once flow returns.

     

Tree and shrub diversity and abundance in fragmented littoral forest of southeastern Madagascar

In the coastal littoral forest of extreme southeastern Madagascar, westudied tree diameter at breast height (DBH) 10 cm in 20, 50× 50 m plots in each of four forest fragments, andunderstorywoody vegetation (DBH < 10 cm, 1 m tall) in60,10 × 10 m plots in three of the fragments. Oneforestfragment was located in the highly degraded Lokaro region, and three in the nearbySainte-Luce forest. Atotal of 3476 trees, representing 169 species in 55 families, were recorded inthe50 × 50 m plots, and 10282 understory stems, representing195 species in 54 families, were found in the 10 × 10m plots. For each tree, DBH was recorded. Mean tree diameter andpatterns of tree size class distribution did not differ among the four forestfragments. However, the fragments differed significantly in both tree andunderstory stem densities, species richness and diversity values, and familyrichness values, with the Lokaro fragment having the lowest values for allmeasures. Furthermore, floristic patterns, family importance values, and communitysimilarity measures revealed that the species composition at theLokaro fragment was very different from the Sainte-Luce fragments. Anthropogenicdisturbance appears most pronounced in the isolated Lokaro forest, where bioticresources are limited to this single fragment.     

No evidence for an interactive effect of herbivore and predator diversity on herbivore abundance in the experimental mesocosms of Douglass et al. (2008)

Douglass et al. ( Ecol. Lett. , 11 , 2008, 1) concluded that grazer diversity and predator diversity have an interactive effect on herbivore abundance in experimental marine mesocosms. Re-analysis of their data fails to support this conclusion, which was apparently based on a statistical miscalculation.     

浙江天童山区灌丛群落的物种多样性及其与演替的关系

根据浙江天童山区灌丛群落的样地调查数据,采用Shannon－Wiener多样性指数、Simpson指数和群落均匀度指数研究了灌丛群落的物种多样性,并与当地的常绿阔叶林进行了比较。结果表明：这3种指标能够有效地表征亚热带灌丛群落的组成结构特征。天童灌丛群落灌木层的物种多样性指数 SW 高于常绿阔叶林中乔木层,而低于常绿阔叶林中灌木层。灌丛群落灌木层的生态优势度 SN 低于常绿阔叶林中乔木层,但高于常绿阔叶林中灌木层。灌丛群落灌木层的群落均匀度 PW 比常绿阔叶林中乔木层的和灌水层的都低。此外,文中还就本区灌丛群落物种多样性的特点,讨论了加速其进展演替的恢复措施。     

坡向和坡位对四川夹金山灌丛群落结构与物种多样性特征的影响

研究不同坡向、坡位夹金山灌丛群落结构和物种多样性特征。结果表明: 在 24 个样地中,共有维管植物 186 种,隶属于 50 科 127 属。其中,灌木层有 32 种,隶属于 14 科 22 属,阴坡下坡位物种数最多;草本层有 154 种,隶属于 43 科 109 属,阴坡物种数最少。灌木层的平均高度表现为阳坡>半阳坡>阴坡,平均密度则相反;草本层平均高度表现为阴坡>半阳坡>阳坡,平均密度无显著变化。坡位仅对阳坡草本层平均高度有显著影响,灌木层物种多样性在阴坡较高,草本层物种多样性在阳坡下坡位和阴坡中坡位较高。坡向对灌木层和草本层 Shannon多样性指数、Simpson优势度指数、物种丰富度指数、Pielou均匀度指数影响显著(除草本层 Simpson 指数),坡位对灌木层和草本层物种多样性指数均无显著影响,坡向和坡位的交互作用对草本层物种多样性的影响大于灌木层。冗余分析(RDA)表明,物种多样性不仅与坡向正弦值、坡向余弦值相关,也与群落结构特征相关性较大。     

丹参田花期昆虫群落结构及多样性研究

为明确丹参田花期昆虫群落结构,本文采用马氏网对丹参花期的昆虫进行收集,分类鉴定后开展群落结构及多样性分析。结果表明,丹参花期共收集到昆虫5 438头,隶属于膜翅目Hymenoptera、双翅目Diptera、半翅目Hemiptera、鳞翅目Lepidoptera、鞘翅目Coleoptera、直翅目Orthoptera、脉翅目Neuroptera 7目52科,双翅目、膜翅目昆虫为优势类群,群落丰盛度、丰富度指数较高,Shannon-Wiener多样性指数、Pielou均匀度指数较为稳定,Simpson优势度指数较低,可见丹参田花期昆虫种群结构较为稳定。     

黔西北地区不同杜鹃灌丛群落特征和物种多样性

为探明黔西北地区不同杜鹃灌丛群落特征和物种多样性变化,本研究以5个不同的杜鹃群落为研究对象,分析了物种组成、重要值和多样性指数。结果表明,5个群落共有33种植物,属16科23属,灌木层和草本层分别有27种和6种;优势种和共优势种植物分别为小果珍珠花、小果珍珠花+露珠杜鹃、小果珍珠花+露珠杜鹃、露珠杜鹃、露珠杜鹃+黄山杜鹃。5个杜鹃灌丛群落灌木层的α多样性指数差异明显,灌木层的Margalef丰富度指数、Simpson多样性指数均表现为露珠杜鹃+黄山杜鹃灌丛群落(V)最大,小果珍珠花灌丛群落(I)最小;Shannon-Wiener多样性指数和Pielou均匀度指数均表现为小果珍珠花+露珠杜鹃灌丛群落(II)最大,小果珍珠花灌丛群落(I)最小。露珠杜鹃+黄山杜鹃灌丛群落(V)有进一步演替为亚热带常绿阔叶林的趋势。杜鹃属植物覆盖度大的临近群落的Whittaker指数、Jaccard指数和Sorenson指数值均较覆盖度小的临近群落大。     

Asexual endophytes and associated alkaloids alter arthropod community structure and increase herbivore abundances on a native grass

Despite their minute biomass, microbial symbionts of plants potentially alter herbivory, diversity and community structure. Infection of grasses by asexual endophytic fungi often decreases herbivore loads and alters arthropod diversity. However, most studies to date have involved agronomic grasses and often consider only infection status (infected vs. uninfected), without explicitly measuring endophyte-produced alkaloids, which vary among endophyte isolates and may impact consumers. We combined field experiments and population surveys to investigate how endophyte infection and associated alkaloids influence abundances, species richness, evenness and guild structure of arthropod communities on a native grass, Achnatherum robustum (sleepygrass). Surprisingly, we found that endophyte-produced alkaloids were associated with increased herbivore abundances and species richness. Our results suggest that, unlike what has been found in agronomic grass systems, high alkaloid levels in native grasses may not protect host grasses from arthropod herbivores, and may instead more negatively affect natural enemies of herbivores.
Ecology Letters (2010) 13: 106–117     

草原沙化与恢复中昆虫群落组成、营养结构及多样性变化研究

为了探讨草原沙化和人工固沙区植被恢复演替过程中昆虫群落组成、营养结构、多样性及稳定性的变化,在宁夏沙坡头自然保护区,利用随机和定点抽样法对上述二过程中不同地段的昆虫进行了调查。结果表明,随着沙化程度的增加和人工固沙区植被演替时间的延长,昆虫群落组成的复杂化和多样性呈现为负向和正向增加的变化趋势,但表现在群落组成结构、演替时间与方向上并不完全一致。随着沙化程度的加重,群落中天敌昆虫比率明显下降,在两个演替过程中,昆虫群落稳定性表现出下降趋势,但群落优势种的组成和不稳定机制明显不同。     

The impact of forest cutting on the diversity of ground beetles (Coleoptera: Carabidae) in the southern Appalachians

Abstract. 1. Carabid beetles were sampled by means of pitfall traps on several clearcut areas and in adjacent forests.
2. A hierarchical analysis of diversity revealed a significant increase in the within-genus component of species diversity after forest cutting.
3. This trend in intrageneric diversity was obscured, with respect to total species diversity, by a nonsignificant reduction in diversity at the generic level.
4. The increase in the within-genus component of species diversity following forest cutting was consistent with the hypothesis that disturbance of a cornmunity can disrupt processes of competitive exclusion.     

Host community structure and the maintenance of pathogen diversity

Community structure has been widely identified as a feature of many real-world networks. It has been shown that the antigenic diversity of a pathogen population can be significantly affected by the contact network of its hosts; however, the effects of community structure have not yet been explored. Here, we examine the congruence between patterns of antigenic diversity in pathogen populations in neighbouring communities, using both a deterministic metapopulation model and individual-based formulations. We show that the spatial differentiation of the pathogen population can only be maintained at levels of coupling far lower than that necessary for the host populations to remain distinct. Therefore, identifiable community structure in host networks may not reflect differentiation of the processes occurring upon them and, conversely, a lack of genetic differentiation between pathogens from different host communities may not reflect strong mixing between them.     

Assessment of the diversity and abundance of terrestrial mangrove arthropods in southern New South Wales,Australia

Abstract The diversity and abundance of arboreal and flying arthropods, in three mangrove patches along the south coast of New South Wales, Australia, was investigated to determine the degree of spatial variability in the assemblages among patches. Intercept traps and restricted canopy fogging were used to sample the communities at Minnamurra, Bonnievale and Kurnell. Twelve orders of arthropods were detected, incorporating 252 morphospecies. Abundance, species richness and species composition were very similar across all patches, the variation being much smaller than expected. These findings suggest that the composition of the arboreal and flying fauna associated with mangrove patches are very similar among patches, but preliminary results also showed that species composition could be highly variable within a patch. Variation between the trapping methods was large, as expected . Intercept trapping and restricted canopy fogging techniques were found to sample different suites of species and therefore complement each other well in sampling programs. Cumulative species curves differed between time periods but generally were flatter for intercept traps than for restricted canopy fogging. Results suggested, for a given level of effort, intercept traps caught a more representative sample of the species composition available to them.     

Tree diversity is key for promoting the diversity and abundance of forest-associated taxa in Europe

Plant diversity is an important driver of diversity at other trophic levels, suggesting that cascading extinctions could reduce overall biodiversity. Most evidence for positive effects of plant diversity comes from grasslands. Despite the fact that forests are hotspots of biodiversity, the importance of tree diversity, in particular its relative importance compared to other management related factors, in affecting forest-associated taxa is not well known. To address this, we used data from 183 plots, located in different forest types, from Mediterranean to Boreal, and established along a climatic gradient across six European countries (FunDivEUROPE project). We tested the influence of tree diversity, tree functional composition (i.e. functional trait values), forest structure, climate and soil on the diversity and abundance/activity of nine taxa (bats, birds, spiders, microorganisms, earthworms, ungulates, foliar fungal pathogens, defoliating insects and understorey plants) and on their overall diversity and abundance/activity (multidiversity, multiabundance/activity). Tree diversity was a key driver of taxon-level and overall forest-associated biodiversity, along with tree functional composition, forest structure, climate and soil. Both tree species richness and functional diversity (variation in functional trait values) were important. The effects of tree diversity on the abundance/activity of forest-associated taxa were less consistent. Nonetheless, spiders, ungulates and foliar fungal pathogens were all more abundant/active in diverse forests. Tree functional composition and structure were also important drivers of abundance/activity: conifer stands had lower overall multidiversity (although the effect was driven by defoliating insects), while stands with potentially tall trees had lower overall multiabundance/activity. We found more synergies than tradeoffs between diversity and abundance/activity of different taxa, suggesting that forest management can promote high diversity across taxa. Our results clearly show the high value of mixed forest stands for multiple forest-associated taxa and indicate that multiple dimensions of tree diversity (taxonomic and functional) are important.     

Specific diversity and community structure of Rotifera in a salinity series of Ethiopian inland waters

The communities of planktonic Rotifera in thirty localities in Ethiopia were examined. All the localities lay at altitudes of over 1100 m and some were over 2000 m. The salinities ranged from 0.12 to 56.3% and in those lakes with salinities over 2% there was a marked reduction in the number of rotifer species, with Brachionus dimidiatus the most frequently dominant. The mean momentary species number in these Ethiopian samples is significantly higher than the means given by Pennak (1947) for Colorado and the rest of the world. Long-term planktonic species numbers in lakes Ziway and Awasa were about three times the mean momentary species number. The dominance ratios in the samples ranged from 19 to 91, but in general were lower than those given by Pennak. The most frequently dominant species were members of the family Brachionidae. Comparison with the data of Tonolli (1962) on the Lago Maggiore indicates that more data are needed on species diversity and dominance before valid geographical comparisons can be made.     

Consequences of protection from grazing on diversity and abundance of the coastal lowland vegetation in Eastern Saudi Arabia

Fourteen years of protection against grazing and human impacts of the coastal lowland vegetation in Eastern Saudi Arabia (an experimental site in the vicinity of Al-Hassa region) has led to an increase of 68% in the total cover, 33% in species richness and 32% in species relative evenness. Many of the species with significantly higher abundance in the protected area are important forage and/or fuel plants. Soil salinity and important soil nutrients (N, K, Mg and Na) are significantly higher in the free grazing area which may be attributable to the fact that the passage of herbage through the grazing animals often enhances nutrient availability.