PJB-2018-784
Effects of grazing intensity on sexual and clonal reproduction in a clonal xerophytic shrub
Yinhua Wang, Lina Xie, Guogang Zhang, Hongyu Guo, Ashley A. Whitt, Weizhong Chen, Lei Han and Chengcang Ma
Abstract
Many plants can reproduce both sexually and clonally, with different consequences for the dispersal, distribution and long-term fitness of plant populations. Understanding the factors and underlying mechanisms that mediate the trade-offs between the two reproduction modes has long been of interest to biologists and ecologists. This knowledge is critical for better understanding the dispersal and sustainability of plant populations in changing environments. Herbivory affects plant growth, and yet how herbivory affects the reproduction mode in clonal flowering plants still remains unclear. In this study, we studied the influence of grazing on the reproduction mode and traits of a dominant xerophytic shrub Caragana brachypoda Pojark using field experiments that under three grazing intensities. Our results showed that both sexual and clonal reproduction of C. brachypoda decreased as grazing intensity increased. Thus, grazing disturbance will likely lead to an aging population structure. Moreover, the proportion of sexual reproduction versus clonal reproduction of this species significantly decreased as grazing intensity increased (with sexual reproduction decreasing to 0% under intensive grazing), which will likely decrease genetic diversity and reduce adaption potential to varying climate conditions over the long run. In addition, because grazing affected seeds and distal ramets more than proximate ramets, it is likely to create a more aggregated distribution pattern of plants, which in turn would enable livestock to graze on this shrub species even more easily due to reduction in travelling costs. Our results suggest that grazing can affect both sexual and clonal reproduction in clonal plants, and can affect mode of reproduction. The effects of grazing on plant reproduction mode are likely to ultimately affect population age structure, population genetic diversity and population distribution patterns, thereby influencing the long-term future of populations even when grazing appears to be sustainable based on plant density
To Cite this article:
Wang, Y., L. Xie, G. Zhang, H. Guo, A.A. Whitt, W. Chen, L. Han and C. Ma. 2020. Effects of grazing intensity on sexual and clonal reproduction in a clonal xerophytic shrub. Pak. J. Bot., 52(5): DOI: http://dx.doi.org/10.30848/PJB2020-5(42)
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