Species diversity and dominant species’ niches of eremophyte communities of the Tugai forest in the Ebinur basin of Xinjiang, China

Abstract

Patterns of species diversity are determined by both species interactions and environmental adaptations. The species composition and environmental factors of the Tugai forest on the north shore of the Aqikesu River was investigated to determine species diversity and the ecological niche of dominant species in the Ebinur basin. Using a multivariate regression tree based on the content of soil water and salinity, our results showed that the plant communities were divided into three associations. The three associations are the Ass. Populus euphratica-Apocynum venetum-Phragmites australis (type I), the Ass. Populus euphratica-Reaumuria songonica (type II), and the Ass. Kalidium foliatum ǁ Populus euphratica-Apocynum venetum + Alhagi sparsifolia (type III). Association I had a weak ability to tolerate extreme environments, including 5 •研究报告• 第 1 期 龚雪伟和吕光辉: 艾比湖流域杜加依林荒漠植物群落多样性及优势种生态位 35 quadrats, while Association II could tolerate mild salt and drought stress, including 3 quadrats, and Association III had a certain degree of adaptability to salty and dry habitats, including 22 quadrats. With succession of typical associations from type I to III, psammophytes and halophytes gradually occupied the habitats and become the dominant species. The Shannon-Wiener biodiversity index and Margalef richness index initially decreased and then increased along with environmental degradation, while the Simpson dominance index and Pielou evenness index showed the opposite trend. The variation of associations and species diversity along the environmental gradient reflects the succession of plant communities. The Bray-Curtis similarity analysis of niche breadth clustered 13 dominant species into two groups, with an average similarity of 96.89% and 97.66%, respectively, reflecting that the niche breadth of species has a high similarity. The pressure coefficient of non-metric multidimensional scaling (NMDS) ordination was 0.04 and except for Halimodendron halodendron and Glycyrrhiza uralensis, and species distribution also had a high similarity. In summary, soil water and salt contents are the main environmental factors that are responsible for plant structure and diversity, and determine the direction of succession. The niche and distribution of dominant species show high similarity, indicating obvious competitive relationship between them.

Retracted: Niches of nine mangrove species in a Sonneratia apetala‐colonized area of Dongzhai Harbor, Hainan Island, China

“…for calculating the importance values and niche characteristics, respectively. PAST v3.10 (Øyvind Hammer, Natural History Museum, University of Oslo, Norway) was used for Bray–Curtis clustering of species by niche width (Gong & Lv, 2017), and produced the cluster result graph (Figure 3). Origin 2018 (OriginLab, Northampton, Massachusetts, USA) was used to generate figures (Figures 1, 2 and 4–6).…”

Estimation of Soil Organic Matter in Arid Zones with Coupled Environmental Variables and Spectral Features

“…The higher importance of the salinity content in the model predictions was reflected in two aspects; on the one hand, salinity and water in the subsoil easily penetrate into the topsoil due to capillary action; on the other hand, increased soil moisture is more conducive to the growth of saline plants and the production and decomposition of apoplastic matter [ 35 ]. Therefore, the SOM content increases [ 27 , 36 ]. Although both LULC and DEM factors are less important for model prediction, they are still the main factors affecting SOM [ 37 ].…”

“…A wavelength was considered significant if b exceeded a threshold. Coefficient values above the threshold were considered significant, and the threshold was set as the standard deviation of its value [ 27 , 28 ]. To assess the relative importance of each wavelength used in each PLSR model in the projection, a VIP score was used to determine the important wavelengths used in the PLSR calibration.…”

Characterization of the gene expression profile response to drought stress in Haloxylon using PacBio single-molecule real-time and Illumina sequencing

“…A previous study that screened candidate genes for Haloxylon drought stress mechanisms by the SMRT-seq technique obtained unclear results. In this study, SMRT and Illumina RNA-seq were used to study H. ammodendron (wet: soil water content 9.70–15.00%; drought: soil water content 2.41–4.00%) and H. persicum (wet: soil water content 3.38–5.12%; drought: Soil water content 1.05–3.11%) in both wet and dry ecological environments ( Gong and Lü, 2017 ). First, the full-length transcriptome sequences from H. ammodendron and H. persicum obtained by Pacbio SMRT technology were described.…”