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Niche realationships among the main herbaceous plant speices and their-responses to foldding distruance on the Songnen Steppe,northeastern China

Authors Wang Zhengwen; Zhu Tingcheng

Journal Acta Prataculturae Sinica , AUG 2014,8:5

DOI 10.1039/c4fo00210e PubMed 24933464

Abstract The interspecific relationships of grassland plants must be affected by flooding disturbance. It is of great significance to disclose the changing patterns of interspecific relationships along the flooding gradient, for studying the adaptation of plant populations to flooding disturbance and for forecasting population dynamics and community succession trends. Using the improved Levins niche breadth index and Schoener niche overlap index, through comparison between transects subjected to flooding disturbance of different durations or intensities, this study analysed niche relationships of major plant populations and their change with increase in flooding intensity, looking at resource dimensions including soil moisture, available nitrogen (N) and available phosphorus (P). The results showed that:l) The niche breadths of most plant populations present on the control transect Towere relatively small, because, on the one hand the low resource availability of transect Toprevented niche expansion of plant populations, and on the other hand the populations growing in the relatively stable habitats of transect To had accustomed to and had intensified selective utilization to a specific range of each kind of resource, which was considered niche specialization. The wider niche breadths of most plant populations on flooded transects compared to the control transect To were the consequences of niche expansion of plant populations when subjected to disturbance, in order to increase survival opportunities in unstable habitats, known as niche generalisation. 2) Basically, with increased flooding disturbance intensity, the niche breadths of hygrophytes such as Scirpus planiculmis and Echinochloa crusgalli increased, while that of meso-xeric Aneurolepidium chinense decreased. 3) Plant species for which habitat change following disturbance is advantageous for survival will more effectively enlarge their ranges of resource use, successfully expand their niche space, and finally, prevail in competition with other plant populations. 4) The hygrophytes have similar demands for water, so the value for niche overlapping between them tended to be highest on more heavily flooded or wetter transects. Niche overlapping between Aneurolepidium chinense and other plant species with change in flooding intensity is mainly determined by differences in ecological demands between them.

Species covered 扁稈藨草 Scirpus planiculmis 稗 Echinochloa crusgalli