Andrewsberry6845

Keystone predator species play an important role in regulating the number, richness and distribution of prey species. Based on the bottom trawl surveys in Haizhou Bay, keystone predator species in fish communities were identified by the revised SURF (supportive role to fishery ecosystems) index. Conger myriaster, Saurida elongata, Hexagrammos otakii, Chelidonichthys spinosus, and Larimichthys polyactis were the keystone predators in the fish community. They had high number of nodes degree, and were also the main predators of many species. Further, they had strong ability of clustering. The fluctuations of their density would have great impacts on ecosystem energy flow and food web structure. The method not only considered the feeding ratio between species, but also took the amount of catch and abundance of species as important factors in the identification of keystone predators. Compared with the traditional method, this method had great improvement and provided a new one for the identification of key predators. Our results showed that the strong inter-specific interactions played an important role in maintaining the structure and function of food webs. Protection of key predators would benefit the stability of biological communities and species diversity. Therefore, ecosystem-based fisheries management (EBFM) should give priority to the protection of key species. The important economic fish species, C. myriaster and L. polyactis, should be protected with high priority as they suffered from higher fishing pressure.Human disturbances have altered global stream ecosystems in multiple ways. Understan-ding spatio-temporal dynamics of aquatic organism composition and their relationships with environmental factors play an important role in revealing changes in the structure and function of river ecosystems. The macroinvertebrates and environmental parameters were sampled in the Yongding River Basin at spring (March), summer (July), and autumn (November) in 2017. The results showed that chironomids were the dominant group in the Yongding River Basin, including Orthocladius, Chironomus, Glyptotendipes, and Polypedilum. Results of the cluster analysis showed significant spatial variations of macroinvertebrate community. Sampling sites were clustered into two groups based on the similarities of macroinvertebrate composition in the Yongding River. Sampling sites belonging to group 1 mainly located in the Sanggan River and Dongyang River, with Orthocladius sp.being the dominant species. Sampling sites belonging to group 2 mainly lst flow to sensitive taxa of EPT (Ephemeroptera, Plecoptera, and Trichoptera). The negative correlations between flow capacity and biodiversity indices implied the adverse effects of high flow on macroinvertebrate biodiversity. Our results confirmed that the composition and biodiversity of macroinvertebrate were affected by both water environment and hydrology, which reflected the multiple human activities in aquatic ecosystems of the Yongding River. It is important to control water contamination and sustain environmental flow at the specific reaches for the restoration of Yongding River.Fusarium oxysporum f. sp. momordica was used as the target pathogenic fungus to screen actinomycetes that were isolated from rhizosphere soil of Momordica charantia by confrontation culture and antifungal tests of fermentation filtrate. The candidate strain 0250 had broad antifungal activity. According to cultural characteristics, physiological and biochemical properties, as well as average nucleotide identity analysis of the strains with similar homology, the strain 0250 was identified as Streptomyces rhizosphaericus. Its effects on growth promotion and control of bitter gourd wilt were evaluated in both greenhouse and field. The results showed that the plate inhibition percentage of S. rhizosphaericus strain 0250 against F. oxysporum f. sp. momordica was 69.2%, while the plate inhibition percentage against 17 plant pathogenic fungi reached 64.3%-85.6%. The suspension treatment of the strain could promote the growth and development of roots and stems and improve production of bitter gourd in pots and field. The control efficacy of Fusarium wilt of bitter gourd was 66.9% and 61.5%, respectively. When soils were treated with the strain 0250 suspension in advance and inoculated with the fungal pathogen, the inhibition percentage on the soil F. oxysporum reached 62.1%. The activity of phenylalanine ammonia-lyase, peroxidase and β-1,3-glucanase as well as root activity were significantly improved in bitter gourd seedlings. In summary, strain 0250 is an actinomycetes resource with biocontrol potential to Fusarium wilt of bitter gourd.In order to provide scientific guidance for soil quality evaluation and optimum management of flower and seedling industry, we investigated the characteristics of soil animal community with different garden plants and various planting periods in Wenjiang District, Chengdu. A total of 10258 soil animals belonging to 26 orders and 78 families were captured in four sampling times. There were significant differences in the taxonomic richness in the plots with different garden plants, generally highest in plots with Loropetalum chinense var. rubrum or Ginkgo biloba and lowest in plot with Zoysia japonica. The taxonomic richness was lower in the plots with different garden plants than the control. Taxonomic richness and abundance of soil fauna in Osmanthus fragrans plot did not change across sampling seasons. The abundance but not taxonomic richness of soil fauna in other plots had obvious seasonal variations. Different garden plants and various planting periods significantly influenced soil faunal diversity indiceculture had negative effects on soil animal community and caused soil degradation.Investigating the response of soil microbial biomass and ecological stoichiometry to tree species transition is of great significance for understanding soil nutrient cycling and availability in forest ecosystems. We measured soil microbial biomass carbon (MBC), nitrogen (MBN), phosphorus (MBP) and their stoichiometry across 0-40 cm soil depth between Mytilaria laosensis and Cunninghamia lanceolata plantations by the chloroform fumigation extraction method, which were replanted after the harvest of C. lanceolata plantation. The results showed that soil MBC in the 0-10 cm layer and soil MBN and MBP in the 0-20 cm layer under the M. laosensis were significantly higher than those under the C. lanceolata. LY3023414 clinical trial The MBC/MBP in the 0-20 cm layer and MBN/MBP in the 10-20 cm layer were significantly lower under the M. laosensis plantation. The MBC/MBN showed no significant differences between the two forests. Soil moisture, organic carbon, total nitrogen, total phosphorus, available phosphorus were positively correlated with MBC, MBN and MBP, but negatively correlated with MBC/MBP and MBN/MBP.