Browsing by Author "Li, Xuehua"

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    Effects of climatic and social factors on dispersal strategies of alien species across China
    (Elsevier, 2020-12) Zhou, Quanlai; Wang, Lixin; Jiang, Zhiyang; Wu, Jing; Cui, Xue; Li, Xuehua; Musa, Ala; Ma, Qu; Yu, Haibin; Wang, Yongcui; Earth Sciences, School of Science
    Determination of dispersal strategies of alien species and its relationship with social and climatic factors are essential to understand the mechanisms of species invasion and adaption. Based on morphological trait, dispersal mode, and dispersal agent of diaspore of 562 alien species across China, we determined: (i) the proportions of five dispersal strategies (i.e., autochory, anemochory, hydrochory, zoochory, and anthropochory), (ii) the relationships between the dispersal strategies and socio-climatic factors in 34 administrative regions across China, and (iii) the correlations between different dispersal strategies. Anthropochory, zoochory, and anemochory account for nearly 90.0% of all the dispersal strategies of alien species. Mean frost days (MFD), mean annual humidity (MAH), and gross domestic product (GDP) were the main climatic and social factors that were correlated to different dispersal strategies. Zoochory was positively related to MFD, but negatively related to the autochory and anthropochory. MAH negatively influenced the anemochory, while GDP positively influenced the hydrochory. We classified the six dispersal strategies into two groups based on the correlations among dispersal strategies, group I included autochory and anthropochory, and group II included anemochory, hydrochory, and zoochory. Within a group, dispersal strategies were positively correlated, while between groups, dispersal strategies were negatively correlated. Positive correlation between different strategies might be co-owned while negative correlation between different strategies might not be co-owned by one alien species. Understanding the characteristics of the dispersal strategies of alien species is important for policy makers when controlling the dispersal of malignant invasive alien species, predicting the distribution, and decreasing or cutting off the dispersal pathways of invasive alien species.
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    Geographical distribution and determining factors of different invasive ranks of alien species across China
    (Elsevier, 2020-06) Zhou, Quanlai; Wang, Yongcui; Li, Xuehua; Liu, Zhimin; Wu, Jing; Musa, Ala; Ma, Qu; Yu, Haibin; Cui, Xue; Wang, Lixin; Earth Sciences, School of Science
    Determination of the geographical distribution and life-form spectra of alien species with different invasive abilities are essential to understand the process of invasion and to develop measures to manage alien species. Based on six classifications of Chinese alien species, environmental and social data, we determined species density, life-form spectrum of alien species, and the relationship between species density of alien species and climatic or social factors. The species density of alien species increased from the northwest to the southeast regions of China for all the six ranks. The boundary line between low and high species density of alien species was consistent with the dividing line of population density (the “Hu Line”). Mean annual precipitation was the most important factor for species density in malignant invaders, serious invaders, local invaders, and species requiring further observation (Ranks I, II, III, and V, respectively). Gross domestic product per square kilometer and annual minimum temperature were the most important factors in mild invaders and cultivated aliens (Ranks IV and VI, respectively). Annual and biennial herbs made up 52.9% to 71.2% of total species in Ranks I to IV; shrubs and trees 3.7% to 14.7%. The annual and biennial herbs were 35.5% and 32.6%, and the shrubs and trees were 25.3% and 31.6% in Ranks IV and VI. Results implied that precipitation was the most important factor on species density for the invasive alien species. However, social factors and temperature were the most important factors for the non-invasive alien species. The invasive alien species had a high proportion of annual and biennial herbs and non-invasive alien had a high proportion of shrubs and trees. It is important to understand the geographical distribution and life-form spectra of various invasive alien species for alien species controls.
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    Scale effect of climate factors on soil organic carbon stock in natural grasslands of northern China
    (Elsevier, 2023-02) Liu, Zhimin; Zhou, Quanlai; Ma, Qun; Kuang, Wennong; Daryanto, Stefani; Wang, Lixin; Wu, Jing; Liu, Bo; Zhu, Jinlei; Cao, Chengyou; Li, Xuehua; Kou, Zhenwu; Shou, Wenkai; Qian, Jianqiang; Liu, Minghu; Xin, Zhiming; Cui, Xue; Liang, Wei; Earth and Environmental Sciences, School of Science
    Changes in grassland soil organic carbon stock (SOCS) may significantly affect the regional climate and carbon cycle of terrestrial ecosystems. However, how the impact of climate factors on SOCS and the dominant climate factors are regulated by the area scale of grasslands remains unclear. To understand the scale effects of climate on SOCS and how to accurately estimate SOCS at different scales, three area scales were defined by extending grassland types on the basis of meadow, typical and desert grasslands (Scale I (average area 37.22 × 104 km2) included each of these three types of grasslands, Scale II (average area 74.45 × 104 km2) was achieved by a pairwise combination of these three types of grasslands. Scale III (area 111.67 × 104 km2) was an aggregate of these three types of grasslands), the relationship between climate factors (i.e., mean annual precipitation, mean annual temperature, annual maximum temperature, annual minimum temperature, mean annual ground temperature, mean annual humidity, annual sunshine duration, annual maximum depth of accumulated snow, and the number of snow-covered days) and SOCS at the three scales were explored in the grasslands of northern China. Our results indicated that the total SOCS in grasslands at the three scales was ordered as desert grassland < meadow grassland < typical grassland. Of the nine climate factors, mean annual precipitation, positively correlated with SOCS, was the most significant climatic factor for all three scales. The dominant climatic factors of the SOCS differed across grassland area scales (i.e., MAP and MAH for meadow grassland, AMAT, MAP, NSD, and MAH for typical grassland, MAP, NSD, MAH, AMAT, and ASD for meadow-typical grassland scale, MAP, MAT, and MAGT for typical-desert grassland scale, MAP and MAT for meadow-typical-desert grassland scale). The impact of climate factors on the SOCS decreased as the scale increased. It is essential to screen appropriate climate predictors according to a given area scale when assessing regional SOCS. Multiple climate factors are better predictors for accessing SOCS at a small scale. At a large scale, however, dominant climatic factors are predictors that are more efficient.
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    The Adaptive Capacity of Alien and Rare Species in China
    (MDPI, 2022-11-27) Zhou, Quanlai; Xin, Zhiming; Wang, Yongcui; Miao, Renhui; Liu, Zhimin; Zong, Lu; Li, Xuehua; Ma, Qun; Liang, Wei; Yu, Haibin; Wang, Lixin; Earth and Environmental Sciences, School of Science
    Alien and rare plants tend to adapt to contrasting biotic and abiotic conditions. However, adaptability assessments of alien and rare plants using biological and habitat characteristics in stressful and disturbed environments are limited. We collected and demonstrated the biological and habitat characteristics and assessed the adaptive capacity of alien and rare plants in China using the analytic hierarchy process. Biological characteristics, such as dispersal strategy, sexual and asexual reproduction modes, life form, and habitat characteristics (e.g., habitat type and distribution spatial extent), are important indicators of the adaptability of alien and rare plants to stressful and disturbed environments. Alien plants have a higher adaptive capacity to disturbed environments than rare plants, while rare plants have a higher adaptive capacity to stressful environments than alien plants. Stressful and disturbed environments constrain the adaptive capacity of alien and rare plants, respectively. However, the constraint on alien plants from stressful environments is weaker than that on rare plants from disturbed environments. Understanding the adaptive capacity of alien and rare plants will help researchers and policymakers develop strategies for preventing the invasion of alien plants as well as protecting rare and endangered plants.