Data From: Seed source climate and precipitation timing determine dryland tree recruitment in hot and dry range margins

Dryland forests face multiple climate change related threats, including more frequent droughts and shifts in the seasonality of precipitation. While dryland tree species tend to have adaptations for adult persistence during drought, recruitment is often episodic, occurring only in years with favorable conditions. As conditions become more arid, with fewer favorable periods for seedling establishment, variation in the presence of drought-adapted phenotypes among populations may determine recruitment potential and lead to different outcomes. We used a four-year common garden experiment to evaluate seedling survival and growth in response to varying precipitation timing and amount for 23 populations of Pinus monophylla, a tree species occurring in semiarid forests of southwestern United States. Previous research on P. monophylla showed that intraspecific phenotypic variation in maternal trees persists in seedling offspring, yet fitness implications are unknown. We sowed seeds at the dry ed..., Seed source locations: Seeds were collected in September 2019 from 23 populations of P. monophylla. We selected nine mountain ranges from across the species’ distribution that spanned regional gradients of mean annual precipitation and proportion of summer precipitation (July, August, September) to annual precipitation using 30-year climate means from PRISM (Daly et al., 1994). At each mountain range, we aimed to locate three seed collection sites along the elevational gradient of P. monophylla, ranging from the lowest- to highest-elevation stands of cone-bearing trees that were accessible from a road. Three mountain ranges had fewer than three sites, due to narrow woodland elevation ranges or a lack of available cones. Common garden location: Our common garden was located near Carson City, NV, USA (39.0729°, -119.784°), at an elevation of 1448 m. The common garden location receives a mean of 245 mm of annual precipitation and has a mean annual temperature of 10.1 °C (30-year mean from ..., # Data From: Seed source climate and precipitation timing determine dryland tree recruitment in hot and dry range margins Dataset DOI: [10.5061/dryad.h18932025](https://doi.org/10.5061/dryad.h18932025) ## Description of the data and file structure This dataset contains the data required to replicate analyses in Urza et al. 2026 (Journal of Ecology). We used a four-year common garden experiment to evaluate seedling survival and growth in response to varying precipitation timing and amount for 23 populations of *Pinus monophylla*, a tree species occurring in semiarid forests of southwestern United States. We sowed seeds at the dry edge of the species’ climatic distribution and used experimental watering treatments to simulate four seasonal precipitation regimes: ambient control (drought), spring supplemental watering, summer supplemental watering, and spring + summer supplemental watering. We used a randomized block design, sowing seeds under the canopy of the native shrub *Artemisia t..., ,干旱林面临多种与气候变化相关的威胁，包括愈发频繁的干旱事件以及降水季节格局的转变。尽管干旱区树木物种往往具备成年个体在干旱期间存活的适应性，但种群更新往往具有偶发性，仅在环境条件适宜的年份才会发生。随着环境愈发干旱，适宜幼苗定植的窗口期愈发减少，不同种群间耐旱表型的差异或许会决定种群更新潜力，并带来各异的结果。 我们依托一项为期四年的同质园（common garden）实验，针对分布于美国西南部半干旱森林的单叶松（*Pinus monophylla*）的23个种群，评估不同降水时间与总量对幼苗存活与生长的影响。此前针对单叶松的研究表明，母树的种内表型变异会在幼苗后代中保留，但该变异对适合度的影响尚不明确。我们在该物种气候分布区的干旱边缘播种种子…… ### 种子采集地点概况 种子于2019年9月从23个单叶松种群中采集。我们从该物种的分布范围中选取了9个山脉，这些山脉覆盖了年平均降水、夏季（7、8、9月）降水占年降水比例的区域梯度，所用数据为PRISM（Daly等，1994）的30年气候平均值。在每个山脉中，我们尝试沿单叶松的海拔梯度设置3个种子采集点，覆盖从公路可达的结球果树木的最低到最高海拔林分。由于林地海拔范围较窄或缺乏可采集的球果，有3个山脉的采集点不足3个。 ### 同质园实验地点 本同质园实验位于美国内华达州卡森城附近（39.0729°，-119.784°），海拔1448米。该地点的年平均降水量为245毫米，年平均气温为10.1℃（30年气候平均值来自……）。 # 数据来源：种子源气候与降水格局决定干旱区树木在炎热干旱分布边缘的种群更新 数据集DOI：[10.5061/dryad.h18932025](https://doi.org/10.5061/dryad.h18932025) ## 数据与文件结构说明 本数据集包含复现Urza等人2026年发表于《Journal of Ecology》（《生态学杂志》）的分析所需的全部数据。我们依托一项为期四年的同质园实验，针对分布于美国西南部半干旱森林的单叶松（*Pinus monophylla*）的23个种群，评估不同降水时间与总量对幼苗存活与生长的影响。我们在该物种气候分布区的干旱边缘播种种子，并通过人工补水处理模拟四种季节降水格局：自然对照（干旱）、春季补水、夏季补水以及春+夏季联合补水。实验采用随机区组设计，在本土灌木*Artemisia t.*的冠层下播种种子……