Table of Content
Volume 27 Issue 4
20 April 2019
Natural Enemy Release is one of the most important hypotheses to explain why non-native plant species can successfully invade in new ranges. Following their long-term establishment, however, invasive plants can also be exploited by native generalist insects because the native host plants are rapidly replaced by the invaders. This exploitation may profoundly affect the insect’s life history. The pictures show the life history of a native insect (Laelia coenosa) feeding on the invasive plant Spartina alterniflora in the saltmarshes of the Yangtze River estuary. (Photo Credit: Ruiting Ju and Wensheng Yu)

Original Papers: Plant Diversity
Genetic diversity and population structure of Populus yunnanensis
Zhang Yahong, Jia Huixia, Wang Zhibin, Sun Pei, Cao Demei, Hu Jianjun
Biodiv Sci. 2019, 27 (4):  355-365.  doi:10.17520/biods.2019016
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Populus yunnanensis is an endemic tree species to Southwestern China. It is a typical southern Populus species that is fast-growing species with easy to clone propagules and is highly adaptable. It is important to research the genetic diversity and population structure of P. yunnanensis for the collection, preservation and utilization of the germplasm resources. In this study, 64 individuals were collected from six populations, spaning the main distribution areas of P. yunnanensis, including Zhaotong (ZT), Huize (HZ), Songming (SM), Eryuan (EY), Lashihai (LS) and Sichuan Meigu (MG). A total of 34 pairs of SSR primers and three pairs of cpDNA primers were used to determine out the genetic diversity and genetic structure. A total of 154 alleles were detected by SSR primers in P. yunnanensis. The average number of alleles was 4.529. The observed heterozygosity (Ho) and expected heterozygosity (He) were 0.552 and 0.472, respectively. And the average genetic differentiation coefficient (Fst) was 0.238. The average polymorphism information content (PIC) was 0.421 and the gene flow (Nm) was 0.806. The results of the DAPC, PCoA and UPGMA analyses showed that the six populations can be divided into three sub-categories: Group І included ZT, HZ and four individuals of SM. Group II included EY, LS and the six remaining individuals of SM; and group III included MG; SM population include mixed genetic components from І and ІІ. A total of 35 variable sites were detected in the three cpDNA combinations, forming 13 haplotypes. Among them, haplotype H5 was the most widely distributed in the population, while the remaining ones were of private haplotypes. Analysis of molecular variance (AMOVA) showed that genetic variation within the population was greater than between populations. The study clarifies that P. yunnanensis has geographical distribution characteristics and is suited to in situ conservation. As ZT population has the highest genetic diversity and contains seven chloroplast haplotypes, it should be given protection priority.

Assembling and analysis of Sanicula orthacantha chloroplast genome
Chen Zhixiang, Yao Xueying, Stephen R. Downie, Wang Qizhi
Biodiv Sci. 2019, 27 (4):  366-372.  doi:10.17520/biods.2018332
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Sanicula orthacantha is a perennial herb widely distributed in China and is a widely used for medicinal purposes. In this study, the whole chloroplast genome was sequenced and analyzed using bioinformatics methods. The results showed that it was a circular molecule 157,163 bp in length with a typical quadripartite structure including a pair of inverted repeats (IRa and IRb) of 26,247 bp that were separated by large and small single copy regions (LSC and SSC) of 87,547 bp and 17,122 bp, respectively. A total of 129 predicted genes, including 84 protein-coding genes, 37 tRNA genes and eight rRNA genes were identified. Compared with other Apiaeceae species, the S. orthacantha chloroplast genome had few differences in size, order and structure. The success of sequencing the S. orthacantha chloroplast genome provides a new method for the complete chloroplast genome assembly and characterization of Sanicula species, providing a methodological guide for the study of Sanicula plant evolution and phylogeny.

Adaptive significance of yellow flowered Bombax ceiba (Malvaceae)
Xiang Wenqian, Ren Mingxun
Biodiv Sci. 2019, 27 (4):  373-379.  doi:10.17520/biods.2019003
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Bombax ceiba is a tall tree species with predominantly red flowers and is normally pollinated by birds. In some populations, a yellow flowered variety occurs. Honeybees frequently visit these uncommon yellow flowers but how this adaptation affects the life history of this variant remains unexplored. In the present study, floral syndrome and pollination mechanism of yellow flowers were compared with red flowers of B. ceiba populations on Hainan Island, southern China. The results showed that main nectar components of two floral phenotypes are both glucose and fructose dominated, and the volatile chemicals are mainly alkanes, esters, phenols and acids with no significant difference between the two phenotypes. The relative spectral reflectance showed that both birds and honeybees could detect the yellow flowers, suggesting visitation by honeybees can compensate for times when bird visitation is low. Compared with red flowers, yellow flower had a lower degree of dichogamy, which might increase selfing possibilities and provide reproduction assurance when red flowers receive low bird visitation. Interestingly, yellow flowers had a relatively higher degree of herkogamy, i.e. stigmas are much higher than anthers when compared to the red flowers. Greater herkogamy in yellow flowers may reflect an adaptation to decreased dichogamy, avoiding autonomous selfing and interference between female and male organs. Fruit set of the yellow phenotype (1.08 ± 0.56)% was lower than that of red phenotype (3.27 ± 0.93)%, suggesting pollen-limitation in B. ceiba. We propose that yellow flowers, with greater herkogamy but lower dichogamy, promote pollination via attracting diverse pollinators and protect red flowers from disturbance of honeybees.

Beta diversity of vascular plants and its drivers in sea-islands of eastern China
Liu Xiangyu, Zhao Ciliang, Xu Mingshan, Liang Qiming, Zhu Xiaotong, Li Liang, Yan Enrong
Biodiv Sci. 2019, 27 (4):  380-387.  doi:10.17520/biods.2018235
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Plant beta diversity describes how species composition shifts along environmental gradients. Islands are characterized by natural boundaries, variation in size and distance from the mainland, and they also experience intensive shifts in environmental properties. To date, plant beta diversity and its association with influencing factors across islands remain poorly understood. This study examined patterns and abiotic drivers of vascular plant beta diversity across 36 sea-islands in eastern China. Beta diversity was quantified using the Jaccard dissimilarity index based on presence/absence data, and patterns and drivers were analyzed by using partial Mantel tests and the variance partitioning approach. In total, there were 1,404 vascular plant species, including 481 woody species, 859 herbaceous species and 64 liana species. Plant beta diversity increased significantly with increase in cross-island distance and distance difference from the mainland. Differences in both island area and climatic factors did not affect plant beta diversity significantly. Cross-island distance accounted for 29.3% of total variation in plant beta diversity. Distance from the mainland explained 2.8%, and island area and climatic differences together explained 0.5%. The pattern of plant beta diversity was consistent between woody and herbaceous plants, but distance-based variables accounted for more beta diversity variation for woody than herbaceous plants (37.5% > 25.3%). Collectively, cross-island distance and the difference between islands in distance from the mainland are the main drivers of plant beta diversity. This suggests that dispersal limitation plays a key role in shaping plant beta diversity in the sea-islands of eastern China.

Interspecific associations and niche characteristics of communities invaded by Decalobanthus boisianus
Jiang Huan, Zhang Hui, Long Wenxing, Fang Yanshan, Fu Mingqi, Zhu Kongxin
Biodiv Sci. 2019, 27 (4):  388-399.  doi:10.17520/biods.2019007
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Decalobanthus boisianus is a noxious weed that has seriously damaged tropical forest ecosystems on Hainan Island due to its rapid dispersal and growth abilities. We investigated 48 communities invaded by D. boisianus and explored the interspecific associations between the community species using χ 2tests, association coefficient (AC), percentage of co-occurrence (PC), and the Ochiai and Dice indices. We assessed community stability using the variance ratio (VR) and contribution law method, and examined niche width, niche similarity and niche overlap of D. boisianus and companion species. Results showed that there were 156 companion species in the D. boisianus communities, belonging to Euphorbiaceae, Rubiaceae, Moraceae, Sapindaceae and Lauraceae. There were positive associations between dominant species. The coordinate (44.53, 55.47) between the inverse accumulative percentage of species and their accumulative relative frequency was far from the stability point (20, 80). This indicates that these communities are in an unstable state. Machilus suaveolens, Litsea variabilis, Garcinia oblongifolia, Elaeocarpus dubius, Schefflera octophylla and Aporusa dioica were closely associated with D. boisianus, indicating that these species have similar resource requirements. Decalobanthus boisianus had the highest niche width which overlapped greatly with companion species. The niches among companion species seldomly overlapped. Our results suggest that the invasion of D. boisianus led to an unstable community with intense competition between companion species and D. boisianus. Our findings can be helpful in species selection for biologically controlling to D. boisianus in tropical areas.

Original Papers: Animal Diversity
Species diversity and potential distribution of Chiroptera on Hainan Island, China
Hu Yifeng, Yu Wenhua, Yue Yang, Huang Zhenglanyi, Li Yuchun, Wu Yi
Biodiv Sci. 2019, 27 (4):  400-408.  doi:10.17520/biods.2018256
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Hainan Island is a key biodiversity hotspot in China with a unique ecosystem and climate. In order to explore the species diversity of Chiroptera on the island, 15 bat surveys were carried out in the area between 2002 and 2016. During these surveys, mist nets, harp traps and other tools were deployed. Captured specimens were identified according to their external form, skull features and phylogenetic description. In total, 1,025 specimens from 5 families, 15 genera and 31 species were recorded and collected. On December 21, 2016, two small Murina bats were captured in a harp-trap in a forest at Chaocan Village, Qiongzhong City, Hainan Province. Based on external, cranio-dental characteristics and phylogenetic evidence, the bats were identified as Murina eleryi. This is the first record of the species on Hainan Island. Based from our survey result and literature review, Chiroptera of Hainan Island consists of a total of 8 families 20 genera and 41 species. The potential distribution area of bats on Hainan Island was mapped using a maximum entropy (MaxEnt) model incorporating 363 local records, derived from our records and the literature. High diversity was predicted for Wuzhi Mountain, Diaoluo Mountain, Yinggeling, Jianfengling and Huoshankou National Geopark whereas the low diversity was predicted for Sanya, Chengmai, Tunchang, Lingao, Qionghai areas. Overall, baseline data for Chiroptera distribution, and resource status was assessed by the current study, which is useful for disease prevention, control, resource conservation and management on Hainan Island.

Effect of soil nematode functional guilds on plant growth and aboveground herbivores
Zhu Baijing, Xue Jingrong, Xia Rong, Jin Miaomiao, Wu You, Tian Shanyi, Chen Xiaoyun, Liu Manqiang, Hu Feng
Biodiv Sci. 2019, 27 (4):  409-418.  doi:10.17520/biods.2019006
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Soil multitrophic interactions are the keystone of understanding mechanisms of ecological function. In order to test the effect of nematode functional guilds on rice growth and Nilaparvata lugens abundance, a pot experiment was conducted by growing rice with a complete factorial design manipulating microbivores (microbivorous nematodes), herbivores (herbivorous nematodes) and omnivore-carnivores (omnivore-carnivorous nematodes). Results showed that compared with no nematodes, herbivores significantly increased rice root biomass (P < 0.05) and total shoot phenolic content (P < 0.05). The microbivores significantly increased N. lugens abundance and significantly reduced root biomass (P < 0.05). Omnivore-carnivores promoted rice shoot growth (P < 0.05), decreased the number of N. lugens (P < 0.05). Higher total phenolic content occurred in treatment receiving all three nematode functional guilds, suggesting stronger potential for insect resistance. In conclusion, organisms at higher trophic levels, such as omnivore-carnivores, could promote plant defense and suppress aboveground herbivory via regulating the herbivores and microbivores. Soil biota managements play central roles in control of trophic level diversity.

Effects of transgenic maize on arthropod diversity
Ma Yanjie, He Haopeng, Shen Wenjing, Liu Biao, Xue Kun
Biodiv Sci. 2019, 27 (4):  419-432.  doi:10.17520/biods.2018316
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The species and numbers of arthropods in fields of transgenic herbicide-tolerant (EPSPS) and insect-resistant (Cry1Ab) maize DBN9936, receptor maize DBN318, conventional maize Xianyu 335, and spraying herbicide transformant DBN9936, were investigated to assess the effect of genetically modified maize on the arthropod communities. Direct observations, pit-fall trapping and longitudinal section methods were used to investigate the field arthropod species in 2015 and 2017. A cluster analysis and species accumulation curves, as well as the Margalef richness index, Shannon-Wiener index and Simpson index, Pielou evenness index, dominant concentration index, community similarity index, were calculated and compared. The recorded arthropod species belonged to 20 orders and 80 families. The number of Lepidopteron insects in the fields of herbicide-free transformant DBN9936 (2015: 10.3 ± 2.6, 2017: 3.3 ± 1.7) and transformant DBN9936 spraying herbicides (2015: 6.0 ± 1.5, 2017: 17.0 ± 0.6) were significantly lower than the corresponding parameters of receptor DBN318 (2015: 20.0 ± 3.2, 2017: 24.0 ± 6.0) and Xianyu 335 (2015: 21.0 ± 8.9, 2017: 26.7 ± 2.0). The species accumulation curves show a typical parabola and there was little difference in the overall species richness. There were no significant differences in the total number of arthropods, functional group composition, richness, diversity, evenness and dominant concentration in the maize fields and there was a high similarity between the arthropods communities. The dynamic of the richness index, diversity index, evenness index, dominant concentration index and community similarity index of those arthropods in the maize fields tended to be consistent. Transformant DBN9936 has obvious resistance to Lepidopteron insects and has no significant negative effects on non-target arthropods. The results suggest that the transformant DBN9936 maize has no significant effect on community richness, diversity, evenness and dominance concentration of arthropods in the fields.

Research Bulletin
Comparison of the life history of a native insect Laelia coenosa with a native plant Phragmites australis and an invasive plant Spartina alterniflora
Yu Wensheng, Guo Yaolin, Jiang Jiajia, Sun Keke, Ju Ruiting
Biodiv Sci. 2019, 27 (4):  433-438.  doi:10.17520/biods.2019035
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The invasion of Spartina alterniflora into saltmarsh ecosystems has resulted in a host transfer of a native generalist insect, Laelia coenosa. Currently, the life history of L. coenosa on S. alterniflora is unclear, although this information is of great importance for evaluating if the native insect can permanently use S. alterniflora. To compare the differences in life history dynamics of L. coenosa between its native host plant Phragmites australis and the invasive host plant S. alterniflora, we investigated the insect occurrence on the two plant habitats in a saltmarsh of the Yangtze River estuary in Chongming, Shanghai. We found that the insect occurred in three generations and overwintered as larvae on both S. alterniflora and P. australis. The larvae started overwintering about 20 days later on the invasive plant than on the native plant, and emerging duration of the insect at most stages of other generations was also approximately 10 days later on the invasive than on native plant. These results suggest that following S. alterniflora invasion the duration of the moth’s appearance on the invasive plant is prolonged however the number of annual generations does not change. We speculate that the differences in growth and development of L. coenosa between S. alterniflora and P. australis may be related to resource availability between plant habitats and the nutritional and defensive levels between plant species.

Species composition and community characteristics of a 25 ha forest dynamics plot in deciduous broad-leaved forest, Qinling Mountains, north-central China
Xie Fenglin, Zhou Quan, Shi Hang, Shu Xiao, Zhang Kerong, Li Tao, Feng Shuiyuan, Zhang Quanfa, Dang Haishan
Biodiv Sci. 2019, 27 (4):  439-448.  doi:10.17520/biods.2018326
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The deciduous broad-leaved forests in the warm temperate-subtropical transition zone of the Qinling Mountains are well preserved. The forests lie in the transition zone from warm temperate to subtropical forests and have a relatively complex community structure. Few studies have been conducted to investigate community structure based on a large-sized plot in this transitional region. This study analyzed species composition and community characteristics within a 25 ha plot, serving as the baseline information for monitoring long-term forest dynamics and diversity in the future. Based on the field protocol of the Center for Tropical Forest Science (CTFS) and the Chinese Forest Biodiversity Monitoring Network (CForBio), a 25 ha deciduous broad-leaved forest plot was established in the temperate-subtropical transition zone. All free standing trees with diameter at breast height (DBH) ≥ 1 cm were tagged, measured and identified to species. A total of 47,739 woody individuals with DBH ≥ 1 cm belonging to 119 species, 66 genera and 36 families were identified. The families and genera of temperate floristic elements accounted for 41.18% and 60.00%, respectively and were the dominant flora in this plot. Fifty-one rare species accounted for 42.86% of the total individuals. Deciduous trees species were dominant accounting for 89.07% of the total species. The 20 species with importance values ≥ 1 contributed 70.35% and 57.41% to the total number of individuals and the total basal area, respectively. The three most abundant species were Quercus aliena var. acutiserrata in the canopy layer, Sorbus alnifolia in the sub-tree layer, and Quercus spinosa in the shrub layer. The mean DBH of all individuals in the plot was 8.61 cm, and the overall structure of DBH size class of all individuals generally shows an inverse “J” type which indicated successful regeneration. All the dominant species exhibited large-scale aggregated spatial distribution closely related to habitat preferences except for Populus purdomii.

Data Paper
Comparison of distinguish ability on seven tree size diversity indices
Lou Minghua, Bai Chao, Hui Gangying, Tang Mengping
Biodiv Sci. 2019, 27 (4):  449-456.  doi:10.17520/biods.2018341
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Tree size diversity directly reflects forest ecosystem health and stability. Objective and appropriate evaluation of tree size is essential for understanding the economic, ecological and social value of natural forests or plantations as well as for effective forest stand management. Four distance-free diversity indices (simpson size diversity index, DN; shannon size diversity index, HN; gini coefficient index of basal area, GC; diameter coefficient of variation index, CVd) and three distance-related indices (simpson size differentiation index, DT; shannon size differentiation index, HT; mean size differentiation index, $\bar{T}$) were selected to analyze the tree size diversity of six types of simulated stands and four measured stand plots with different diameter distribution and spatial patterns. The results show that regardless of extreme that such as compared stands have the same diameter composition but have different size mingling, GC, CVd, $\bar{T}$, DT and HT can distinguish tree size diversity between stand types which have different diameter distributions objectively and properly. CVd had the best result followed by GC. Accounting for extreme, the distance-related indices, namely $\bar{T}$, DT and HT can distinguish the difference between different size mingling stands. CVd and GC can be used as the preferred indices in the practical application for calculating simple facilitate. $\bar{T}$can be used to analyze the dynamic changes of forest structural characteristics for its high distinction ability of spatial difference that due to its sensitivity to regeneration.

Reviews
Research progress of interspecific hybridization in genus Ficus
Huang Jianfeng, Xu Rui, Peng Yanqiong
Biodiv Sci. 2019, 27 (4):  457-467.  doi:10.17520/biods.2018318
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Hybridization plays a vitally important role in biological evolution and speciation. Although occurring frequently in nature, the prevalence of hybridization events is unevenly distributed across the plants. It is generally considered unlikely for the obligate insect-pollinated plants, due to the much stronger prezygotic barriers which were developed during their long co-evolutionary with the host-specific pollinators, such as the fig-fig-pollinating wasp mutualism. Species-specificity in fig pollination appears to be extreme compared with most other insect pollination mutualisms. Most fig species are pollinated by only one wasp species and most wasps are associated with just a single fig species. However, increasing cases of host shift have been reported with the deepening of research, which raises the research and discussion on hybridization between host fig species. Here, the research progress on the interspecific hybridization in Ficus is presented from the following five aspects, artificial hybridization, hybridization between exotic and native species, natural hybridization of island species, natural hybridization of sympatric allied species, and hypothesized hybridization by phylogenetic incongruence. Some further research prospects on the Ficus interbreeding are also outlined. Artificial F1 hybrids between the closely related species of the same subgenus are usually fertile. However, intensity difference of cross-fertilize compatibility between species of different subgenera exists between the different breeding systems. There is unidirectional or bidirectional but asymmetrical interspecific gene flow. Introgression may be the most prominently and prevalently hybridization process in Ficus because of the extreme dependence on pollinating fig wasps for sexual reproduction. A series of prezygotic isolation mechanisms maintain the genetic and morphological identity of fig species, including chemical, mechanical, geographic, temporal and ecological isolation. However, the postzygotic isolation is weak effective. The reproductive fitness of pollinating fig wasp is reduced obviously in atypical host species. Future research work needs to be carried out in investigating the effect of hybridization on fig biodiversity and the stability of the fig-fig-pollinating wasp mutualism, and exploring hybridization pattern and consequence of the hybrid zone, and the factors that affect the host shift and hybridization, and so on.

Fitness advantage and maintenance mechanisms of dimorphic mixed- mating plants
Hu Wenzhao, Zhao Jimin, Zhang Yanwen
Biodiv Sci. 2019, 27 (4):  468-474.  doi:10.17520/biods.2019002
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Plants that have a dimorphic mixed-mating system consisting of open chasmogamous flowers (CH) and closed cleistogamous flowers (CL) have special reproductive strategies. Further research on CH-CL mating systems can help us understand the maintenance mechanism, evolutionary trends and strategies of plants in response to environmental change. This paper reviews existing literatures on dimorphic flowers (dimorphic mixed-mating system) of CH-CL systems including the effects of different abiotic and biological factors on the growth, development and relative proportion of flowers. It also reviews the maintenance mechanisms and evolutionary significance of dimorphic flowers. Recent researches of CH-CL system and remaining scientific questions are outlined and the new understanding of CH-CL systems based on recent research is reviewed. We suggests that it is necessary to accurately detect the differences between the progeny of the two flower forms in heterogeneous habitats and at different stages of life history. The microenvironment (separation pattern and location effect of seeds) is also identified as being very important for seed germination and the growth and development of the two flower types. Additionally, the expression mechanism of the spatial and temporal differences in flower types (the pattern of flowering and sensitivity to heterogeneous habitats) may be related to changes at the levels of endogenous hormones. It has been said that the distribution of populations of different natures and different sources, and the impact on the genetic structure, is likely to be an important mechanism for the maintenance of the system. Therefore, in-depth research and scientific understanding of dimorphic mixed-mating system may be of great significance for understanding the evolution of the entire plant reproductive system.

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