Proxy soil temperature and moisture regimes (climate regimes) in southwestern U.S. drylands: 1980-2019

Spatially explicit and climate sensitive information on the responses of ecosystems to global change processes is required for strategic planning and prioritization of conservation and restoration. Indicators of ecological resilience and invasion resistance (R&R) are used increasingly to understand the influence of climate regimes on ecosystem responses to global change processes and determine effective management strategies. We developed proxy soil temperature and moisture regimes, or climate regimes, for southwestern U.S. drylands that accounted for precipitation seasonality and climate change at a scale of 1 kilometer (km) for the time period from 1980-2019. The climate variables that we used, mean annual temperature, precipitation, and monsoon index, allowed us to construct climate sensitive and ecologically meaningful climate regimes that mirrored the soil temperature and moisture regimes in the U.S. National Cooperative Soil Survey data and Ecological Site Descriptions that are widely used by managers in the western U.S. This data publication provides climate regimes raster data (GeoTIFF format) that include four temperature regimes (cryic, frigid, mesic, and hypermesic), both ustic and xeric/aridic moisture regimes, and multiple moisture subclasses based on average precipitation zones (PZ). The climate regimes reflected the dominant ecological types and plant functional groups and allowed us to develop meaningful indicators of R&R. Particularly important was identification of a monsoon index value (0.30) to delineate areas with an ustic (summer moist) precipitation regime as indicated by the frequency of C4 vs. C3 grass species.生态系统对全球变化过程的响应需要具备空间显性与气候敏感性的相关信息，以支撑保护与修复工作的战略规划及优先级排序。生态系统恢复力与入侵抗性（Resilience and Resistance，R&R）指标正被愈发广泛地应用于解析气候格局对生态系统响应全球变化过程的影响，并助力制定高效的管理策略。本研究针对美国西南部干旱区构建了替代土壤温度与湿度格局（亦可称为气候格局）数据集，该数据集以1千米（km）为空间分辨率，覆盖1980-2019年时段，纳入了降水季节动态与气候变化因素。本研究选取的气候变量包括年平均气温、降水量与季风指数，借此构建了具备气候敏感性且生态学意义明确的气候格局，该格局与美国西部管理者广泛采用的《美国国家合作土壤调查》（U.S. National Cooperative Soil Survey）数据及《生态站点描述》（Ecological Site Descriptions）中的土壤温度与湿度格局高度吻合。本数据集提供了气候格局栅格数据（格式为GeoTIFF），涵盖4种土壤温度格局（寒冻（cryic）、冷凉（frigid）、中温（mesic）与高温（hypermesic））、常湿润（ustic）与干旱/极干旱（xeric/aridic）水分格局，以及基于平均降水带（PZ）划分的多类水分亚类。该气候格局能够反映区域优势生态类型与植物功能群特征，助力我们构建具备科学意义的R&R指标体系。尤为关键的是，本研究确定了季风指数阈值0.30，可用于划分具备常湿润（夏季多雨）降水格局的区域，该划分依据为C4与C3草本植物的物种占比频率。