Demography of the giant monocarpic herb Rheum nobile in the Himalayas and the effect of disturbances by grazing.

摘要: BACKGROUND Perennity of giant rosette species in combination with a single 'big bang' reproduction followed by death the genetic individual is relatively rare among plants. Such long-lived monocarpic plants are usually slow growing and can be found deserts, bogs or alpine regions tropics sub-tropics. Due to their longevity, perennials risk losing everything before reproduction, which make them particularly susceptible disturbances. Because inherent difficulties assessing whether populations declining, neither demography nor consequences increasing grazing pressure known. METHODS We used integral projection modelling (IPM) measure growth rate passage time flowering Rheum nobile, perennial, one most striking from high Himalayas. Rosettes were no longer due disturbances yaks either treated as missing dead two series analysis, thereby simulating without impact cattle. Data collected at 4500 m a.s.l. Shangri-la County, Yunnan Province, south-west China. In four consecutive years (2011-2014) populations, 372 369 individuals measured, respectively, size-dependent growth, survival fecundity parameters estimated. addition, germination percentage, seedling establishment probability assessed. KEY RESULTS The survival, strongly size dependent. Time reach was 33.5 [95 % confidence interval (CI) 21.9-43.3, stochastic estimate pooled transitions populations]. population (λs) nobile 1.013 (95 CI 1.010-1.017). When disturbance cattle (yaks) accounted for model, λs dropped values <1 (0.940, 95 0.938-0.943). CONCLUSION conclude that natural this unique viable, but conservation efforts should made minimize protect slow-growing flagship plant