Studies on endemism are always of high interest in biogeography and contribute to better understanding of the evolution of species and making conservation plans. The present study aimed to investigate the endemism patterns of planthoppers in China by delimiting centers of endemism and areas of endemism. We collected 6,907 spatial distribution records for 860 endemic planthopper species from various resources. Centers of endemism were identified using weighted endemism values at 1° grid size. Parsimony analysis of endemicity and endemicity analysis were employed to detect areas of endemism at 1°, 1.5°, and 2° grid sizes. Six centers of endemism located in mountainous areas were identified: Taiwan Island, Hainan Island, eastern Yungui Plateau, Wuyi Mountains, western Qinling Mountains, and western Yunnan. We also delimited six areas of endemism, which were generally consistent with centers of endemism. Our findings demonstrated that mountainous areas have an essential role in facilitating the high level of endemism and formation of areas of endemism in planthoppers through the combined effects of complex topography, a long-term stable environment, and geological events. Dispersal ability and distribution of host plants also have important effects on the patterns of planthoppers’ endemism.
Although many hypotheses have been proposed to understand the mechanisms underlying large-scale richness patterns, the environmental determinants are still poorly understood, particularly in insects. Here, we tested the relative contributions of seven hypotheses previously proposed to explain planthopper richness patterns in China. The richness patterns were visualized at a 1° × 1° grid size, using 14,722 distribution records for 1335 planthoppers. We used ordinary least squares and spatial error simultaneous autoregressive models to examine the relationships between richness and single environmental variables and employed model averaging to assess the environmental variable relative roles. Species richness was unevenly distributed, with high species numbers occurring in the central and southern mountainous areas. The mean annual temperature change since the Last Glacial Maximum was the most important factor for richness patterns, followed by mean annual temperature and net primary productivity. Therefore, historical climate stability, ambient energy, and productivity hypotheses were supported strongly, but orogenic processes and geological isolation may also play a vital role.
To evaluate the seasonal dynamics of phytoplankton and its relationships with aquatic habitat factors in polluted urban landscape lakes, annual investigations have been carried out in the West zone of Xinkai Lake. The results showed that the lake belongs to the eutrophic-supertrophic type in terms of key habitat factors measurement. The seasonal succession of phytoplankton community was determined. The dominant cyanobacterial species Oscillatoria tenuis Ag. bloomed in autumn, although the other species with higher degrees of dominance never bloomed in the year investigated. Significant correlations between some habitat factors and phytoplankton biomass were observed.
Two new cixiid planthopper species: Andixius
longispinus Zhi & Chen, sp. n. and A.
trifurcus Zhi & Chen, sp. n. are described and illustrated from China (Yunnan Province) to provide the genus with four species in total. The generic characteristics are redefined. A key based on male genitalia to the four known species of this genus and a map of their geographic distributions are provided.
This paper reviews the major changes in China's trade policies in the last few years. During this period, the adjustment of trade policies has developed in the following ways: first, the establishment of free trade zones, which emphasises the importance of advanced systems rather than preferential policies; second, putting forward the “Belt & Road” Initiative, which indicates China's new stage of development from “bringing in” to “going out”; third, holding import expos, which marks an era when China's foreign trade development has shifted from focusing on exports only to focusing on both exports and imports; fourth, reducing entry barriers of foreign capital, which demonstrates that the policy framework for FDI has gradually changed from a positive list to a negative list; fifth, promoting trade negotiations, which reflects that China has actively participated in bilateral, regional and multilateral trade talks; and finally, building up new experimental fields of reform and opening up, which shows evidence that a new generation of special economic zones is emerging.
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