Masting, or the synchronous and irregular production of seed crops, is controlled by environmental conditions and resource budgets. Increasing temperatures and shifting precipitation regimes may alter the frequency and magnitude of masting, especially in species that experience chronic resource stress. Yet the effects of a changing climate on seed production are unlikely to be uniform across populations, particularly those that span broad abiotic gradients. In this study, we assessed the spatiotemporal patterns of masting across the latitudinal distribution of a widely distributed dryland conifer species, pinon pine Pinus edulis. We quantified seed cone production from 2004 to 2017 using cone abscission scars in 187 trees from 28 sites along an 1100 km latitudinal gradient to investigate the spatiotemporal drivers of seed cone production and synchrony across populations. Populations from chronically hot and dry areas (greater climatic water deficits and less monsoonal precipitation) tended to have greater interannual variability in seed cone production and smaller crop sizes. Mast years generally followed years with low vapor pressure deficits and high precipitation during key periods of the reproductive process, but the strength of these relationships varied across the region. Populations that received greater monsoonal precipitation were less sensitive to late summer vapor pressure deficits during seed cone initiation yet more sensitive to spring vapor pressure deficits during pollination. Spatially correlated patterns of vapor pressure deficit better predicted synchrony in seed cone production than geographic distance, and these patterns were conserved at distances up to 500 km. These results demonstrate that aridity drives spatiotemporal variability in seed cone production. As a result, projected increases in aridity are likely to decrease the frequency and magnitude of masting in these dry forests and woodlands. Declines in seed production may compound climatic limitations to recruitment and impede tree regeneration, with cascading effects for numerous wildlife species.

中文翻译：

---

干旱在旱地针叶树的纬度范围内驱动桅杆的时空模式

Masting，或种子作物的同步和不规则生产，受环境条件和资源预算控制。升高的温度和不断变化的降水状况可能会改变桅杆的频率和幅度，特别是在经历长期资源压力的物种中。然而，气候变化对种子生产的影响不太可能在种群中是一致的，尤其是那些跨越广泛非生物梯度的种群。在这项研究中，我们评估了分布广泛的旱地针叶树松柏 Pinus edulis 的纬度分布中桅杆的时空模式。我们使用来自 1100 公里纬度梯度的 28 个地点的 187 棵树的锥体脱落疤痕量化了 2004 年至 2017 年的种锥产量，以研究种锥产量和种群同步性的时空驱动因素。来自长期炎热和干燥地区（更大的气候缺水和更少的季风降水）的人口往往在种锥生产和更小的作物尺寸方面具有更大的年际变化。在繁殖过程的关键时期，肥大年通常紧随蒸气压不足和降水量高的年份，但这些关系的强度在整个地区各不相同。接受较大季风降水的种群在种子锥开始期间对夏末蒸汽压力不足的敏感性较低，但在授粉期间对春季蒸汽压力不足更敏感。与地理距离相比，蒸气压不足的空间相关模式更好地预测了种子锥生产的同步性，并且这些模式在长达 500 公里的距离内得以保存。这些结果表明干旱驱动了种锥生产的时空变异性。因此，预计干旱的增加可能会降低这些干燥森林和林地中桅杆的频率和幅度。种子产量的下降可能会加剧气候限制，阻碍树木再生，对许多野生动物物种产生连锁效应。与地理距离相比，蒸气压不足的空间相关模式更好地预测了种子锥生产的同步性，并且这些模式在长达 500 公里的距离内得以保存。这些结果表明干旱驱动了种锥生产的时空变异性。因此，预计干旱的增加可能会降低这些干燥森林和林地中桅杆的频率和幅度。种子产量的下降可能会加剧气候限制，阻碍树木再生，对许多野生动物物种产生连锁效应。与地理距离相比，蒸气压不足的空间相关模式更好地预测了种子锥生产的同步性，并且这些模式在长达 500 公里的距离内得以保存。这些结果表明干旱驱动了种锥生产的时空变异性。因此，预计干旱的增加可能会降低这些干燥森林和林地中桅杆的频率和幅度。种子产量下降可能会加剧气候限制，阻碍树木再生，对许多野生动物物种产生连锁效应。因此，预计干旱的增加可能会降低这些干燥森林和林地中桅杆的频率和幅度。种子产量的下降可能会加剧气候限制，阻碍树木再生，对许多野生动物物种产生连锁效应。因此，预计干旱的增加可能会降低这些干燥森林和林地中桅杆的频率和幅度。种子产量的下降可能会加剧气候限制，阻碍树木再生，对许多野生动物物种产生连锁效应。