Groundwater and remotely sensed phenology reveal vulnerability of riparian trees to drought

The increasing frequency and magnitude of climatic extremes are altering water availability in dryland ecosystems globally. However, riparian vulnerability to hydroclimate whiplash remains poorly understood. Here, we examined how riparian willow, cottonwood, and valley oak trees respond to groundwater fluctuations and drought through their water use patterns and phenology. To this end, we combined time-series analysis of in situ, high-frequency groundwater monitoring with high-resolution PlanetScope satellite imagery of a drought-prone and relatively pristine watershed in California (Chalone Creek, Pinnacles National Park). We found that flow regime dictates the potential for trees to access groundwater, while the identity of tree species determines the timing and magnitude of their use. Machine-learning models revealed that at intermittent sites, groundwater depth predominantly controlled vegetation greenness, represented by Normalized Difference Vegetation Index (NDVI). In contrast, v..., , # Data from: Groundwater and remotely sensed phenology reveal vulnerability of riparian trees to drought ## Description This repository contains the data and R code necessary to reproduce the analyses and figures presented in the manuscript, \"Groundwater and remotely sensed phenology reveal vulnerability of riparian trees to drought.\" The analysis investigates the relationship between groundwater availability, drought, and the phenological shifts in riparian tree species. ### Code: Mohammadi_et_al_2025.Rmd Code description: R Markdown script to reproduce all analyses and figures #### Dataset: SC-5_all.csv Dataset description: This dataset contains groundwater elevation data for well SC-5 (perennial) used in the wavelet analysis date: date elevation_ft: elevation (ft) of water table elevation_m: elevation (m) of water table #### Dataset: CHA-4_all.csv Dataset description: This dataset contains groundwater elevation data for well CHA-4 (intermittent) used in the wavelet analysi...,全球范围内，气候极端事件的发生频率与强度持续攀升，正改变着旱地生态系统的水资源可利用格局。然而，河岸生态系统对水文气候急变（hydroclimate whiplash）的脆弱性仍有待深入解析。本研究通过树木水分利用模式与物候特征，探究了河岸柳、三角叶杨与河谷橡树对地下水位波动及干旱的响应机制。为此，我们结合了原位（in situ）高频地下水位监测的时间序列分析，与美国加利福尼亚州查隆溪（Chalone Creek）尖顶国家公园（Pinnacles National Park）内易受干旱侵扰且相对原生的流域的高分辨率PlanetScope卫星影像。研究发现，水流情势决定了树木获取地下水的潜力，而树木物种特性则决定了其水分利用的时机与强度。机器学习模型揭示，在间歇性水源站点，地下水位深度主导了以归一化植被指数（Normalized Difference Vegetation Index，NDVI）表征的植被绿度变化。与之相对，[原文此处截断]。# 数据来源：《地下水与遥感物候揭示河岸树木的干旱脆弱性》（Groundwater and remotely sensed phenology reveal vulnerability of riparian trees to drought） ## 数据集说明 本仓库包含复现该论文中所有分析与图表所需的全部数据及R语言代码。本分析旨在探究地下水可利用性、干旱胁迫与河岸树木物候变化之间的关联。 ### 代码文件：Mohammadi_et_al_2025.Rmd 代码说明：用于复现所有分析与图表的R Markdown脚本 #### 数据集：SC-5_all.csv 数据集说明：本数据集包含用于小波分析的SC-5号井（常年性水源井）的地下水位高程数据 - date：观测日期 - elevation_ft：地下水位高程（英尺） - elevation_m：地下水位高程（米） #### 数据集：CHA-4_all.csv 数据集说明：本数据集包含用于小波分析的CHA-4号井（间歇性水源井）的地下水位高程数据[原文此处截断为"wavelet analysi..., "]