English N B, Dettman D L, Hua Q, Mendoza J M, Muir D, Hultine K R, Williams D G
School of Health, Medical and Applied Science, Central Queensland University, 538 Flinders St West, Townsville, QLD 4810, Australia.
Department of Geosciences, University of Arizona, Tucson, AZ 85721, USA.
Conserv Physiol. 2021 Jan 12;9(1):coaa123. doi: 10.1093/conphys/coaa123. eCollection 2021.
The tall (>4 m), charismatic and threatened columnar cacti, pasacana [ (Vaupel) Friedrich & G.D. Rowley)], grows on the Bolivian Altiplano and provides environmental and economic value to these extremely cold, arid and high-elevation (~4000 m) ecosystems. Yet very little is known about their growth rates, ages, demography and climate sensitivity. Using radiocarbon in spine dating time series, we quantitatively estimate the growth rate (5.8 and 8.3 cm yr) and age of these cacti (up to 430 years). These data and our field measurements yield a survivorship curve that suggests precipitation on the Altiplano is important for this species' recruitment. Our results also reveal a relationship between nighttime temperatures on the Altiplano and the variation in oxygen isotope values in spines (δO). The annual δO minimums from 58 years of in-series spine tissue from pasacana on the Altiplano provides at least decadal proxy records of temperature ( = 0.58; < 0.0001), and evidence suggests that there are longer records connecting modern Altiplano temperatures to sea-surface temperatures (SSTs) in the Atlantic Ocean. While the role of Atlantic SSTs on the South American Summer Monsoon (SASM) and precipitation on the Bolivian Altiplano is well described, the impact of SSTs on Altiplano temperatures is disputed. Understanding the modern impact of SSTs on temperature on the Altiplano is important to both understand the impact of future climate change on pasacana cactus and to understand past climate changes on the Altiplano. This is the best quantitative evidence to date of one of the oldest known cactus in the world, although there are likely many older cacti on the Altiplano, or elsewhere, that have not been sampled yet. Together with growth, isotope and age data, this information should lead to better management and conservation outcomes for this threatened species and the Altiplano ecosystem.
高大（>4米）、具有魅力且受到威胁的柱状仙人掌——帕萨卡纳仙人掌[（沃佩尔）弗里德里希和G.D.罗利]生长在玻利维亚高原上，为这些极其寒冷、干旱且海拔较高（约4000米）的生态系统提供环境和经济价值。然而，人们对它们的生长速率、年龄、种群统计学以及气候敏感性知之甚少。利用刺中的放射性碳年代测定时间序列，我们定量估算了这些仙人掌的生长速率（每年5.8厘米和8.3厘米）和年龄（长达430年）。这些数据以及我们的实地测量得出了一条存活曲线，表明高原上的降水对该物种的补充很重要。我们的研究结果还揭示了高原夜间温度与刺中氧同位素值变化（δO）之间的关系。从高原上帕萨卡纳仙人掌连续58年的刺组织中获取的年度δO最小值提供了至少十年的温度代理记录（r = 0.58；p < 0.0001），并且有证据表明存在将现代高原温度与大西洋海面温度（SST）联系起来的更长记录。虽然大西洋SST对南美夏季风（SASM）以及玻利维亚高原降水的作用已得到充分描述，但SST对高原温度的影响仍存在争议。了解SST对高原温度的现代影响对于理解未来气候变化对帕萨卡纳仙人掌的影响以及了解高原过去的气候变化都很重要。这是迄今为止世界上已知最古老仙人掌之一的最佳定量证据，尽管高原上或其他地方可能还有许多尚未采样的更古老仙人掌。连同生长、同位素和年龄数据，这些信息应该能为这个受威胁物种和高原生态系统带来更好的管理和保护成果。
