Plant Diversity ›› 2022, Vol. 44 ›› Issue (06): 607-616.DOI: 10.1016/j.pld.2021.07.003

• Research paper • Previous Articles     Next Articles

Seedling survival after simulating grazing and drought for two species from the Pamirs, northwestern China

Fiona R. Worthya, Stefanie D. Goldberga,b, Sailesh Ranjitkarc,d, Jian-Chu Xua,b,c   

  1. a. CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, Yunnan, China;
    b. CIFOR-ICRAF China Program, World Agroforestry (ICRAF), Kunming 650201, Yunnan, China;
    c. Honghe Center for Mountain Futures (CMF), Kunming Institute of Botany, Chinese Academy of Sciences, Honghe County 654400, Yunnan, China;
    d. Faculty of Agroforestry, Lumbini Buddhist University, Lumbini, Nepal
  • Received:2021-02-04 Revised:2021-07-05 Online:2022-11-25 Published:2022-12-13
  • Contact: Jian-Chu Xu,
  • Supported by:
    This work was supported by a Yunnan Provincial Human Resources and Social Security Bureau Post-Doctoral Grant, Chinese Academy of Sciences President's International Fellowship Initiative grant [grant number 2020FYC0003], the National Sciences Foundation China [grant number 41661144001] and the Key Research Program of Frontier Sciences [grant number QYZDY-SSW-SMC014].

Abstract: For plant populations to persist, seedling recruitment is essential, requiring seed germination, seedling survival and growth. Drought and grazing potentially reduce seedling recruitment via increased mortality and reduced growth. We studied these seed–related processes for two species indigenous to the Pamir Mountains of Xinjiang in northwestern China: Saussurea glacialis and Plantago lessingii. Seeds collected from Taxkorgan, Xinjiang, had a viability rate of 15.8% for S.?glacialis but 100% for P.?lessingii. Of the viable seeds, the highest germination rates were 62.9% for S.?glacialis and 45.6% for P.?lessingii. In a greenhouse experiment, we imposed a series of stressful conditions, involving a combination of simulated grazing and drought events. These had the most severe impact on younger seedlings. Modelling showed that 89% of S.?glacialis mortality was due to early simulated grazing, whereas 80% of P.?lessingii mortality was due to early simulated drought. Physiological differences could contribute to their differing resilience. S.?glacialis may rely on water storage in leaves to survive drought events, but showed no shifts in biomass allocation that would improve grazing tolerance. P.?lessingii appears more reliant on its root system to survive grazing, but the root reserves of younger plants could be insufficient to grow deeper in response to drought. After applying all mortality factors, 17.7 seedlings/parent of P.?lessingii survived, while only <0.1 seedlings/parent of S.?glacialis survived, raising concerns for its capacity to persist in the Pamirs. Inherent genetic differences may underlie the two species’ contrasting grazing and drought responses. Thus, differing conservation strategies are required for their utilization and protection.

Key words: Medicinal plant, Pastoralist, Plantago lessingii, Saussurea glacialis, Soil moisture, Water deficit