Responses of ground-dwelling spiders to four hedgerow species on sloped agricultural fields in Southwest

Spiders are important predators in aeroecosystems and contribute to the control of agricultural nect nnnulatinns.Hahitat manage-ment such as the creation of new semi-natural habitats around or within fields enhances spider abundance and species diversity.Using pitfall traps,we investigated the effects of four hedgerow plant svecies.which serve as undisturhed and permanent semi-narimal habitats,on ground-dwelling spider activity density(a parameter of nonulation density and relative activitv)and species richness.Samples were ollected over two winter wheat and two summer maize growing seasons druing 2005-2007 in trial field 1(slope gradient of 20%)and field 2(slope gradient of 12%)at the Ziyane Experimental Site in Sichuan Province,China.The hedgerow species evaluated were Amorpha fruticosa(field 1).Vetiveria zizanioides(field 1),EulahODsis binata (field 2),and Afediraon sativa(field 2).CnmnareA to rnntrnl plots,hedgerow plots had significantly higher activity density and species richness of ground-dwelling spiders within strips in both fields 1 and 2 during the wheat growing season.The presence of hedgerow strins did not augment the activity density and species richness of ground-dwelling spiders within the crop fields during the wheat or maize growing seasons.The ground-dwelling spider activity density within hedgerow strips was significantly higher in the Vetiveria than in the AmorDha nlots and in the Medicago than in the Eulaliopsis plots,and the species richness was significantly higher in the Vetiveria than in the Amornha plots during the wheat season. Our results suggest that hedgerows may serve as important overwinterine sites for ground-dwelling spiders durinjthe wheat growing season.In addition,the diversification of agroecosystems by using hedgerow strips may be a viable strategy for maintaining ground-dwelling spider populations in agricultural areas.However,ground-dwelling spiders did not move into adiacent crop fields;therefore,future work should address the mechanisms of attracting spiders into crop fields,thereby contributing to the bio-control of pests.     

Anurans of Turvo State Park: testing the validity of Seasonal Forest as a new biome in Brazil

The composition of the anuran community of Turvo State Park was compared with that of other localities of Mesophytic semideciduous Forest, aiming to test the hypothesis that localities situated nearest the Misiones nucleus support the new phytogeographic unit, known as Tropical Seasonal Forests Region. In total 32 amphibian species were recorded in the park area and surroundings: Anura, 30 native species and one exotic; Gymnophiona, one species. The ordination among the 20 localities of Seasonal Forest showed the formation of three groups with 45% similarity: group 1, composed of localities of south-eastern and central western regions; group 2, composed of the localities of the transitional portion with the Atlantic Forest sensu stricto and group 3, composed of the southern localities. The consolidation of the second group, which includes the occurrence of endemic species, supports the proposal of a new phytogeographic unit.     

The effect of altitude on arid inselbergs along a bioclimatic gradient

Twenty-four inselbergs in four distinct landscapes along a biogeographic gradient from mesic winter rainfall in the southern Namib to arid summer rainfall in the northern Namib were analysed. Declining similarity of vegetation between matrix (surrounding plains) and inselbergs with altitude were exhibited in most inselbergs, irrespective of biogeographic region, rock types and height above surroundings. Some inselbergs showed the least congruence with matrix vegetation on upper slopes, others with the top of inselbergs. This is probably related to the nature of the individual inselbergs, e.g. with steep cliffs in the upper reaches supporting plant species adapted to more mesic conditions. Most trends of declining similarity between matrix and inselberg habitats were maintained across the investigated bioclimatic regions. Even low inselbergs clearly supported vegetation very distinct from the surrounding area. Their contribution to species richness of a landscape is therefore unquestionable and adequate protection of such landscapes is needed where human impacts are severe.     

Laser-induced fluorescence of macerals in relation to its hydrogen richness

On the basis of results from conventional elemental analyses and a unique technique (FAMM®; fluorescence alteration of multiple macerals), using a laser fluorescence microprobe, the fluorescence characteristics of various macerals are systematically related to hydrogen content. The amount of fluorescence from inertinite and vitrinite exponentially increases with HIC values. Although liptinite has high fluorescence and high HIC values, the relationship does not follow the same trend as defined for the other maceral groups. Because petroleum yields of a maceral mainly depend upon hydrogen richness, a correlation also exists between fluorescence, and gas to oil ratios from pyrolysis. Because individual organic entities are measured, the laser fluorescence microprobe has the benefit of accommodating heterogeneous organic matter in source rocks and enables determination of oil and gas yields of specific macerals.     

Diversity and taxonomy of intertidal Bryozoa (Cheilostomata) at Akkeshi Bay,Hokkaido, Japan

We found 39 cheilostome species among more than 7000 specimens collected at 10 intertidal sites in rocky habitats along the shore of Akkeshi Bay, eastern Hokkaido Island, Japan. These species are herein described in detail and illustrated by scanning electron microscopy. Nine species (23% of total) are described as new (Electra asiatica, Callopora sarae, Conopeum nakanosum, Cauloramphus cryptoarmatus, Cauloramphus multispinosus, Cauloramphus niger, Stomachetosella decorata, Microporella luellae, and Celleporina minima), and 21 species (54%) are reported for the first time from Japan. Species richness ranged from eight to 29 species per study site. A TWINSPAN analysis showed the species fell into nine groups defined by the local pattern of distribution. A cluster analysis of study sites based on similarity of species composition showed three faunistic groups distributed geographically: in Akkeshi Lake, along the eastern‐central shore of the bay, and at the mouth of the bay. Species richness in estuarine Akkeshi Lake was low, with a species composition very different from the outer bay. Most cheilostomes were found on rock and shell substrata, but uncommonly occurred on concrete walls, algae, hydroids, tubes of polychaetes, other bryozoans, and anthropogenic debris. Of the 39 species found, 33 (85%) contained embryos during the collecting periods, 2–7 June and 3–6 July 2004. The biogeographical composition of intertidal cheilostomes at Akkeshi Bay included species with Arctic‐Boreal (28%), Boreal (59%), and Boreal‐Subtropical (13%) distributions. The overall species richness of intertidal cheilostomes was two‐thirds that documented intertidally in a comparable study at Kodiak, Alaska, a locality 15° higher in latitude. We attribute the lower richness at Akkeshi to differences in the nearshore marine environment between the two localities.     

基于非下采样剪切波变换与显著信息加权的图像融合算法

为了克服当前较多图像融合方法主要依靠测量图像能量信息来完成不同系数的融合,忽略了图像的显著内容,导致融合图像含有吉布斯效应及间断效应等弊端,设计了非下采样剪切波变换(nonsubsampled Shearlet transform,NSST)耦合显著信息加权的图像融合算法.引入NSST机制,对源图像进行系数分解,获取高、低频系数.借助高斯滤波器来构造出显著度量模型,以计算图像拥有的显著信息.随后,利用信息熵函数来计算出图像拥有的细节丰富度.并以图像拥有的细节丰富度和显著信息为依据,设计低频系数融合的加权因子,以此完成低频像素的融合.最后,利用图像中像素点的三邻点像素值,融合高频系数,获取融合图像.实验结果显示,与当前图像融合技术相比,所提算法融合质量更好,融合结果连续性较强,所对应的平均梯度值较大.     

柑橘园树冠蜘蛛群落物种丰富度与调查株数的关系分析

柑橘园树冠蜘蛛群落物种丰富度(S)与调查株数(q)之间的关系式为S=2.280q0.787,经X2检验,理论数与观察数之间具较高的吻合度.柑橘园树冠蜘蛛群落调查的"最小株数"为9株.     

中国荨麻科植物地理分布

结合文献资料研究和在各地开展荨麻科植物调查,对荨麻科植物的物种丰富度、特有性指数、相似性系数、垂直分布和水平分布进行数据处理,结果表明:该科植物的分布中心在滇、桂一带;特有性中心在台、滇、藏、桂等地;相似性系数较大是地理上相近、环境异质性较小的地区;垂直分布中心为500～2 000m;水平分布中心为东经90°～120°和北纬20°～35°.受地理环境、气候因素等影响,荨麻科植物主要分布在高原地区,平原、丘陵地区种植较少,且品种缺乏.     

Coexistence of two sympatric and morphologically similar bat species Rhinolophus affinis and Rhinolophus pearsoni

Ecologists have long focused on the coexistence of sympatric species. Here, we investigated two horseshoe bat species, Rhinolophus affinis and R. pearsoni inhabited in the same cave, for their foraging strategies, niche differentiation, prey selection, and their coexistence status. These two species of horseshoe bats were different in the dominant frequency of their echolocation calls but similar in their morphology. We found evidence for prey selectivity although there was a high degree of overlap in prey categories and sizes. R. affinis and R. pearsoni foraged on 16 and 7 categories insects, respectively, with Pyralidae, Geometridae, Melolonthidae dominating their diets. The degree of trophic niche overlap was 0.69. Pairwise comparisons suggested that there was no obvious differentiation in prey categories and size. However, high prey availability in the environment (Simpson diversity index = 0.79 and Margalef richness index ＝ 4.12) contributed to their coexistence by dampening the interspecific competition. Since there are one or more mechanisms facilitating species coexistence in a community, our results suggest that the spatial niche differentiation in foraging microhabitats and in foraging habitats at landscape scale may promote the coexistence of the two bat species. However, additional field data are needed to confirm this speculation.     

How does contemporary climate versus climate change velocity affect endemic plant species richness in China？

Climate change is considered a top threat to biodiversity, but the relative roles of contemporary climate versus the rate of climate change in determining spatial patterns of biodiversity are far from clear. China has a very diverse flora and harbors a high percentage of endemic species, but the mechanisms underlying spatial patterns of plant endemism are poorly understood. This study explores the geographical patterns of a representative sample of 555 endemic seed plant species at the scale of 0.5° latitude × 0.5°longitude. Ordinary least squares and spatial autoregressive models were compared to assess the relationship between richness of endemics and the rate of climate change in the past century, as well as a group of contemporary climate variables. In China, a high level of endemism was associated with high elevation and low rate of climate change. However, contemporary climate had a stronger impact than climate change velocity in the past century on endemic species richness patterns. Specifically,mean annual precipitation and annual range of temperature were important contemporary climatic factors. The rate of change of annual mean temperature, but not that of annual precipitation, also significantly contributed to the spatial pattern of plant endemic species richness. We found no significant relationship between topographic variation and endemic species richness, while temperature variability at multiple time scales was strongly correlated with the species richness pattern. Future work should consider the direction of climate change and incorporate higher-resolution data.