Interactions between aboveground-belowground communities play an important role in regulating terrestrial ecological processes; however, the interactions between rice varieties, herbivory and the soil community are often ignored. A pot experiment with a full 2×2 factorial design was conducted to examine the impacts of the brown planthopper (Nilaparvata lugens) and rice variety (susceptible or resistant) on the soil nematode community. The results showed that, after nine days, aboveground herbivory significantly (P<0.05) increased total abundance, numbers of nematode genera and the number of free-living nematodes (such as bacterivores, fungivores, and predators), under the rice varieties susceptible to the brown planthopper (Guangsi and Shanyou63), whereas an opposite trend was observed under the rice varieties resistant to the brown planthopper (Shanyou559 and IR36). In the presence of planthoppers, herbivorous nematodes significantly increased under the most susceptible rice variety Guangsi but significantly decreased under the most resistant rice variety IR36. Both planthopper and rice variety had negligible influences on ecological indices of the soil nematode community, including nematode channel ratio (NCR), Shannon-Wiener index (H'), maturity index (MI), enrichment index (EI) and structure index (SI). This might be due to domination by bacterivores of the soil nematode community and the short length of exposure to aboveground herbivory for our pot experiment (only nine days). In conclusion, the brown planthopper strongly affects the abundance, composition as well as trophic structure of nematode community, but the direction (i.e. stimulation or depression) and magnitude of influences interacts with the rice variety. Our results imply that short-term aboveground herbivory may impose profound impacts on the structure and functions of rice paddy ecosystem.

In 2008, an ice storm caused extensive damage to the montane evergreen broadleaved forest in Chebaling National Nature Reserve, Guangdong Province, China. To assess the response of soil arthropod diversity and distribution to a gradient of canopy openness following the ice storm, 17 plots, each 400 m², were selected within a 2-ha permanent plot. Canopy openness was estimated with hemispherical photography in each plot. We sampled the litter layer and two soil layers (0-10 cm and 10-20 cm) to measure arthropod diversity and soil properties. We used two-way cluster analysis to group sites based on arthropod abundance in the litter layer. We also utilized canonical correspondence analysis to reveal relationships between soil arthropods in the 0-10 cm layer and four environmental variables, i.e., canopy openness (CO), soil organic matter (SOM), electric conductivity (EC), and natural moisture content (NMC). Results showed that abundance, richness and diversity of arthropod communities decreased with depth. A negative association was found between canopy openness and the number of arthropod groups in the litter layer; some arthropod taxa, such as the Oribatida, Prostigmata and Mesostigmata, were found in a wide range of light conditions, whereas the Hymenoptera, Symphyla, Pseudoscorpiones and Lepidoptera larvae may be photophobic. The distribution of arthropods in the 0-10 cm soil layer was closely related to CO, SOM, EC, and NMC on the first and second canonical axes. Hence, a series of changes in canopy structure and soil factors following the ice storm appeared to have affected the composition and distribution of soil arthropod communities. Findings from the present study also indicated that arthropod communities could serve as indicators to characterize the ecosystems they inhabit, thus being particularly suitable for monitoring forest regeneration and successional dynamics following ice storms.

To explore how density of potential cavity resources (including cavities and artificial nest boxes) affects the composition and distribution of secondary cavity-nesting guilds, as well as the community structure of breeding birds, we studied plots with different densities of nest cavities in Dagang Forestry Farm, Jilin Province, China from November 2007 to July 2008. Based on the density of cavity resources, the nine sample sites were divided into three treatments, i.e., NBP (nest-box plots with less cavities and high-density nest boxes), LDP (low-density cavities plots without nest boxes) and HDP (high-density cavities plots without nest boxes). We then surveyed avian communities and noted the use of cavities and artificial nest boxes. All the treatments contained four primary cavity excavators, and three species were the same. Four secondary cavity nesters were widespread in the three treatments, including the great tit (Parus major), marsh tit (P. palustris), yellow-rumped flycatcher (Ficedula zanthopygia) and eurasian nuthatch (Sitta europaea). Total densities of secondary cavity nesters in NBP and HDP were higher than that of LDP. Densities of great tits and yellow-rumped flycatchers were higher in NBP and HDP than in LDP, because they were major users of nest boxes. There were no significant differences in the densities of marsh tits and eurasian nuthatches among treatments. A significant positive correlation was detected between the density of primary cavity excavators and cavity density, and also between the density of secondary cavity nesters and potential cavity resources. Bird species diversity indices were lower in LDP than in NBP and HDP. Nest-box addition could potentially regulate the composition of avian communities by increasing bird species diversity indices. We observed no differences in evenness, species richness indices or probability of interspecific encounter (PIE) among treatments, and Sørensen similarity indices differed little among treatments. There were no obvious differences in structure of breeding bird guilds between HDP and LDP. Nine species were found in all the three treatments, and their densities were not affected by the temporary increase in secondary cavity nesters. We hypothesize that density of primary cavity excavators determines the density of cavities in forests, which may change distributional patterns of secondary cavity-nester guilds, and therefore affect the structure of breeding avian communities.

In southern China, fengshuiforests are distinctive woodlands that are treated as a protective barrier behind rural villages. Likely due to their socio-cultural importance to indigenous people, these forests have been conserved over the past several hundred years and play a significant role in conservation of local biodiversity. To reveal the effects of human disturbance on fengshui forests, we compared the species composition and diversity of understory woody plants among three fengshui forests with similar topographic situation and identical origin under different degrees of disturbance intensity in Dalingshan Town of Dongguan City, Guangdong Province. The low, medium and high disturbance level of fengshui forest stands were identified according to impact factors such as road length, agricultural land, residential area, factory area, cutting degree and garbage cover. Multi-response permutation procedures (MRPP) analysis showed that the composition of understory woody species (P= 0.001, A = 0.3886) differed among forest stands. Meanwhile, the proportion of mesophytes decreased with disturbance and the proportion of heliophytes increased. Though not statistically significant (P> 0.05), diversity indices consistently showed the following trend: high disturbance > medium disturbance > low disturbance. Jaccard coefficients of understory species similarity among the threefengshui stands declined with increasing intensity of human disturbance, indicating that species replacement occurred. Two-way cluster analysis of the relationships between plant species and forest stands indicated that the spatial distribution of understory species differed among stands. Indicator species analysis (ISA) identified species that were indicative (importance value ≥60) of the three forest stands studied, and therefore potential indicators of different disturbance regimes. We conclude that human disturbance of fengshui forests appeared to alter understory species composition, and favor the establishment and growth of heliophytes, but failed to affect species diversity. Furthermore, identification of candidate understory indicators which capture key ecological responses to human disturbance may have significant implications for improving biodiversity conservation and ecosystem management of fengshui forests.

Crocus alatavicus, a geophytic-geocarpic plant, is an early spring ephemeral species that grows in subalpine areas of the western Tianshan Mountains. To understand the ecological significance of geocarpy in plants, we studied the breeding system and pollination biology of C. alatavicus, with special reference to its adaptive strategies for a subalpine existence. We found that C. alatavicus is hysteranthous and its flowering pattern was explosive at the population level. It began to flower in early- to mid-April, and the white flowers had neither nectar nor scent. The inferior ovary was below ground at anthesis, while the other floral parts were aboveground. The flowers were open during the day and closed at night, and individual flower duration was 6-9 days. Pollen viability was 75.39±5.69% at the end of anthesis, and stigma receptivity lasted eight days. Results of artificial pollination experiments suggested that the breeding system ofC. alatavicusis facultative xenogamy with the ability to self-pollinate spontaneously. Crocus alatavicushas a generalist pollination system, with Bombus lucorum, Anthophora senilis and Andrena capillosa being effective pollinators. These insects initiated pollination while foraging for pollen, and their visitation frequencies were 0.50±0.27, 0.18±0.08 and 0.13±0.05 per flower per hour, respectively. Thus,C. alatavicusnot only has evolved unique flowering pattern and generalist pollination system, but also utilizes an otherwise vacant niche in the early spring to improve the effectiveness of pollination. Furthermore, characteristics of its breeding system, such as self-compatibility and spontaneous self-pollination, ensure reproductive success even when pollinators are scarce and pollinator visitation frequencies are low in early spring.

In the present study, a high intra-genomic polymorphism was detected in the internal transcribed spacer (including ITS1, 5.8S and ITS2) regions of Cycas revoluta, suggestive of incomplete concerted evolution. Detailed comparisons of the ITS sequences from C. revoluta and those from other species further suggested that some divergent ITS paralogs from C. revoluta were likely pseudogenes. Some of these putative pseudogenes may have rather long evolutionary histories, because they have diverged substantially in sequences. We proposed that the incomplete concerted evolution in C. revoluta may have resulted from the high number and dispersed distribution of the nucleolus organizer regions (NORs) in the genome.

In order to assess genetic variation in Chinese rapeseed (Brassica napus), the genetic diversity of 91 cultivars released in recent years was assessed using EST-SSR markers. In total, 100 amplified fragments were detected using 16 EST-SSR primer pairs; of these fragments 84 were polymorphic. The number of amplified and polymorphic fragments was 6.25 and 5.25 per primer pair, respectively. The PIC (polymorphism information content) value of these markers varied from 0.022 to 0.926, averaging 0.677. The genotypes revealed by each marker ranged from 2 to 24 with average of 12.44. Genetic distance (GD) varied widely, from 0.0530 to 0.7223, suggesting the presence of broad genetic variation in the accessions we used. Diversity was higher in hybrid varieties and varieties released after the year 2000 than in traditional open-pollinated varieties and varieties released before or during the year 2000, respectively. At GD = 0.313 the tested varieties could be classified into three groups clustered by UPGMA, in which the first group containing 87 cultivars could be further divided into 10 sub-groups at GD = 0.223. The cluster results generally agreed with pedigree analysis and reveal the true genetic variation in the materials tested.

The relationship between the bacterial communities and eutrophication of aquatic ecosystem is not clear. We investigated and analyzed the planktonic bacterial diversity and phylogeny of Wuliangsuhai Lake by using the construction of 16S rRNA gene clone library, and discussed the relationship between the bacterial community and eutrophication. Totally 87 clones were digested with HaeIII and were grouped into 23 operational taxonomic units (OTUs). The estimate of library coverage showed that the library coverage value was of 73.6%, which indicated that the clone library could provide a fine inventory of bacterial diversity in the lake. Each representative clone of the 23 types was finally sequenced and homology analysis showed that the majority were affiliated to α-, β-, γ-Proteobacteria, Bacteroidetes, and Actinobacteria, which accounted for 10.3%, 41.4%, 4.6% and 6.9%, respectively. However, unlike bacterial composition of typical freshwater, the water had 10.3% of total bacteria slightly halo-and-alkaline-philic, making the composition unique. Moreover, 83.9% of total bacteria were lower than 97% of homology with cultured species, of which 58.9% were even failed to be identified at genus level, while ones (16.1% of total bacteria) affiliated to the cultured with the ability for pollutants degradation. Bacteroidetes and Firmicutes, and some groups of β-Proteobacteria came into dominant groups in the water, which could be the result of responding to the eutrophication.

To determine the diversity of arbuscular mycorrhizal (AM) fungi in the rhizosphere of tea plant (Camellia sinensis) in Laoshan region, Shandong Province, we selected and sampled 12 representative tea gardens. Soil samples were collected from these gardens in September 2007. Spores of AM fungi were identified to reveal the species richness, frequency, spore density, relative abundance, importance value and Shannon-Wiener indices of AM fungi. Species diversity and composition of AM fungal community were also compared among the 12 tea gardens. A total of 22 species belonging to three genera were identified according to the morphological characteristics of the spores isolated from soil samples collected using wet-sieving techniques. The relative abundance of the genus Acaulosporawas the highest, followed by Glomus. Soil samples from Xiaowang Village Tea Garden showed the highest spore density, while Gaojia Village soils were the lowest. Species richness in soil samples from Changjiacun Village and Sangyuan Village Tea Garden was significantly higher than that in other tea gardens. Species diversity was highest in the Changjiacun Village Tea Garden. Acaulospora laeviswas the dominant species in Beilao Tea Garden, Wanglijiang Tea Garden, Yingshanchun Tea Garden, Wanlijiang Organic Tea Garden, Changjia Village, and Sangyuan Village Tea Garden, while Acaulospora undulata was the most common species in Gaojiacun Village and Wanlaike Tea Garden. Glomus occultum occurred most frequently in Yingshanchun Tea Garden, Xiaowang Village and Wanlaike Tea Garden. Relationships between environmental factors and AM fungi spore density in the Laoshan Tea region were determined using Canonical Correspondence Analysis, and their relative degree of impact on density was as follows: available phosphorus content>soil organic matter content>tree age>soil available nitrogen content>soil pH>soil available potassium content.

To elucidate the diversity of arbuscular mycorrhizal (AM) fungi associated with the common desert plant Artemisia ordosica, we sampled, in April 2007, the following four representative sites in the Mu Us Sandland and Tengger Desert regions: Yulin Psammophyte Garden (Yulin), Yanchi Desert Shrub Garden (Yanchi), Ordos Sandland Ecological Research Station (Research Station), and Shapotou Desert Research and Experiment Station (Shapotou). We collected soil samples from the rhizosphere ofA. ordosica and divided them into five depth intervals, each 10 cm, to 50 cm depth. A total of 28 AM fungal species from four genera were isolated. Of these, 16 species belonged to Glomus, 7 to Acaulospora, 4 to Scutellospora and 1 toDiversispora. Glomus mosseae was the dominant species. Acaulospora bireticulata andG. reticulatum were common species (>25% frequency of occurence) andG. constrictum was rare species (≤25% frequency of occurence) at the four sampling sites.Glomus geosporum was found only in Yanchi, G. melanosporum only in Yulin and A. mellea, A. lacunosa, G. coremioides and G. magnicaule occurred only in Research Station. Richness of AM species was highest in Yanchi and Research Station and spore density was highest in Yulin. Species richness and spore density were the lowest in Shapotou. Generally, spore density, isolation frequency, relative abundance and importance value followed the trend Glomus > Acaulospora > Paraglomus > Diversispora. Our results are the first to assess the considerable diversity of arbuscular mycorrhizal fungi found in association with Artemisia ordosica. Further research should concentrate on understanding the dynamics of these relationships.

To reveal patterns of longitudinal distribution, seasonal variation, and ecological succession in cladocerans communities in the Three Gorges Reservoir, ten sites were used to sample cladoceran communities across a longitudinal gradient from April, 2004 to January, 2005. Nine cladoceran species were collected throughout the year. Species richness was highest in spring (8 species), lower in summer (5 species) and winter (3 species), and lowest in autumn (2 species). Cladoceran species composition varied across sampling sites. Four species were collected from river sampling sites and seven species from reservoir sampling sites. Cladoceran species richness decreased gradually with increasing distance to the dam within the reservoir area. Cladoceran density and biomass varied among seasons (P <0.01) and sampling sites ( P <0.01), and both were highest in spring. Density and biomass of cladocerans in river areas were lower than in the reservoir area. Density and biomass of cladoceran in up area of reservoir was lower than that in down area of reservoir. The cladoceran communities of the Three Gorges Reservoir showed distinct patterns in both longitudinal distribution and seasonal variation.

To estimate genetic variation and provide genetic information for resource protection and breeding efforts, individuals of the invasive red swamp crayfish (Procambarus clarkii) from four populations along the lower reaches of the Yangtze River (Nanjing, Xuyi, Hefei and Nanchang) were characterized using 17 microsatellite loci. In these populations, the mean observed heterozygosity (H_o), mean expected heterozygosity (H_e), and mean polymorphism information content (PIC) ranged from 0.4322 to 0.4826, from 0.4024 to 0.6121, and from 0.3408 to 0.5624, respectively, indicating a medium level of genetic diversity. The highest and lowest genetic diversity were found in the Nanjing population and Hefei population, respectively. Gene flow (N_m) ranged from 1.3729 to 5.9161, and population differentiation (F_st) ranged from 0.0405 to 0.1540. Cluster analysis using the UPGMA method showed that the Nanjing and Nanchang populations clustered first, and then clustered with the Xuyi population, and finally all groups together clustered with the Hefei population.

Biological diversity of ecosystems are traditionally measured by several diversity indices such as species richness, Simpson index, Shannon index. But these indices are not appropriate tools to analyze the changes of community diversity when soil fauna are classified into broad taxonomic units although a great shift of habitat appears. To overcome this limitation, Liao (1990, 2009) reported a new diversity index, known as density-group index (DG index). Many researchers reported thatDGindex, as a measure of diversity, is widely applicable to estimate soil faunal diversity. However, after reviewing recent documented data on soil fauna community diversity by several researchers, we found a negative correlation between Pielou’s evenness index andDGindex (r = -0.534,P =0.000). A higher evenness may lead to a lower diversity value. Using these data for further correlation analysis, strong positive relationships betweenDGindex and taxon number (r = 0.648,P =0.000) and taxon density (r = 0.487,P =0.000) appeared. It indicates that decrease in taxon number could be compensated with increasing density of some taxa. Therefore, loss of some taxa in a faunal community may lead to a constant or higher diversity ranges. Due to this reason, we do not suggest thatDGindex could be used as a diversity measurement. Furthermore, to explore intrinsic implication ofDGindex as a community parameter, we propose that the mean ratio of actual density to potential density of each taxon as parameter estimation for percent of community achieving potential abundance (maximum). By all means, if we useDGindex as an indicator of actual habitat condition, it might be a measurement of potential of increase in community abundance in the habitat.