Browsing by Author "Chen, Pengdong"

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    Fluctuations in resource availability shape the competitive balance among non-native plant species
    (Wiley, 2024) Tao, Zhibin; Shen, Changchao; Qin, Wenchao; Nie, Baoguo; Chen, Pengdong; Wan, Jinlong; Zhang, Kaoping; Huang, Wei; Siemann, Evan
    Fluctuating resource availability plays a critical role in determining non-native plant invasions through mediating the competitive balance between non-native and native species. However, the impact of fluctuating resource availability on interactions among non-native species remains largely unknown. This represents a barrier to understanding invasion mechanisms, particularly in habitats that harbor multiple non-native species with different responses to fluctuating resource availability. To examine the responses of non-native plant species to nutrient fluctuations, we compared the growth of each of 12 non-native species found to be common in local natural areas to nutrients supplied at a constant rate or supplied as a single large pulse in a pot experiment. We found that seven species produced more biomass with pulsed nutrients compared to constant nutrients (hereafter “benefitting species”), while the other five species did not differ between nutrient enrichment treatments (hereafter “non-benefitting species”). To investigate how nutrient fluctuations influence the interactions among non-native plant species, we established experimental non-native communities in the field with two benefitting and two non-benefitting non-native species. Compared with constant nutrient supply, the single large pulse of nutrient did not influence community biomass, but strongly increased the biomass and cover of the benefitting species and decreased those of the non-benefitting species. Furthermore, the benefitting species had higher leaf N content and greater plant height when nutrients were supplied as a single large pulse than at a constant rate, whereas the non-benefitting species showed no differences in leaf N content and were shorter when nutrients were supplied as a single large pulse than at a constant rate. Our results add to the growing evidence that the individual responses of non-native species to nutrient fluctuation are species-specific. More importantly, benefitting species were favored by nutrients coming in a pulse, while non-benefitting ones were favored by nutrients coming constantly when they grew together. This suggests that nutrient fluctuations can mediate the competitive balance among non-native plants and may thus determine their invasion success in a community harboring multiple non-native plant species.
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    Native diversity contributes to composition heterogeneity of exotic floras
    (Wiley, 2023) Chen, Pengdong; Shen, Changchao; Ren, Jie; Qin, Wenchao; Yi, Jiahui; Guan, Shuping; Tao, Zhibin; Huang, Wei; Siemann, Evan
    Variation in species composition among sites (beta diversity) is generally thought to be driven by environmental filtering and dispersal limitation, but the role of biotic interactions has not been sufficiently addressed. Specifically, the early species in a local community may contribute to subsequent beta diversity patterns. Exotic assemblages within native communities provide a unique opportunity to study biotic interaction mechanisms. In this study, we conducted a field survey of plants over an approximately 1800-km transect in the middle and lower Yangtze River valley in China to study how native communities influence exotic beta diversity. The survey included 459 plots in 51 local plant communities with 40 exotic species and 103 co-occurring native species. We also investigated how 11 environmental factors involving climate conditions, soil properties, and human activity regulate the interaction between native and exotic plants. The results showed that native diversity (Shannon–Wiener index) increased exotic beta diversity. Environmental conditions, especially monthly minimum temperature, influenced exotic beta diversity indirectly through native diversity rather than directly. Our results suggest that lower native diversity driven by environmental conditions, especially warmer temperatures, led to a decrease in composition heterogeneity of the exotic flora. Our results will help to incorporate biotic interactions into the framework of beta diversity mechanisms for local community assembly.