California’s Central Valley, USA is a critical component of the Pacific Flyway despite loss of more than 90% of its wetlands. Moist soil seed (MSS) wetland plants are now produced by mimicking seasonal flooding in managed wetlands to provide an essential food resource for waterfowl. Managers need MSS plant area and productivity estimates to support waterfowl conservation, yet this remains unknown at the landscape scale. Also the effects of recent drought on MSS plants have not been quantified. We generated Landsat‐derived estimates of extents and productivity (seed yield or its proxy, the green chlorophyll index) of major MSS plants including watergrass (Echinochloa crusgalli) and smartweed (Polygonum spp.) (WGSW), and swamp timothy (Crypsis schoenoides) (ST) in all Central Valley managed wetlands from 2007 to 2017. We tested the effects of water year, land ownership and region on plant area and productivity with a multifactor nested analysis of variance. For the San Joaquin Valley, we explored the association between water year and water supply, and we developed metrics to support management decisions. MSS plant area maps were based on a support vector machine classification of Landsat phenology metrics (2017 map overall accuracy: 89%). ST productivity maps were created with a linear regression model of seed yield (n = 68, R² = 0.53, normalized RMSE = 10.5%). The Central Valley‐wide estimated area for ST in 2017 was 32,369 ha (29,845–34,893 ha 95% CI), and 13,012 ha (11,628–14,396 ha) for WGSW. Mean ST seed yield ranged from 577 kg/ha in the Delta Basin to 365 kg/ha in the San Joaquin Basin. WGSW area and ST seed yield decreased while ST area increased in critical drought years compared to normal water years (Scheffe’s test, P < 0.05). Greatest ST area increases occurred in the Sacramento Valley (~75%). Voluntary water deliveries increased in normal water years, and ST seed yield increased with water supply. Z scores of ST seed yield can be used to evaluate wetland performance and aid resource allocation decisions. Updated maps will support habitat monitoring, conservation planning and water management in future years, which are likely to face greater uncertainty in water availability with climate change.

中文翻译：

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通过遥感量化干旱对加利福尼亚中央谷地潮湿土壤种子植被的影响。

尽管损失了超过90％的湿地，但美国加利福尼亚的中央谷地还是太平洋航线的重要组成部分。现在，通过模拟管理湿地的季节性洪水来生产潮湿的土壤种子（MSS）湿地植物，从而为水禽提供必要的食物资源。管理人员需要MSS的工厂面积和生产力估算来支持水禽保护，但是在景观尺度上仍然未知。另外，最近的干旱对MSS植物的影响还没有被量化。我们得出了Landsat得出的主要MSS植物（包括草（Echinochloa crusgalli）和灵芝（Polygonum spp。）（WGSW）和沼泽提摩太（Crypsis schoenoides）的范围和生产力（种子产量或其替代物，绿色叶绿素指数）的估算值）（ST）从2007年至2017年在所有中央谷地管理的湿地中进行。我们使用多因素嵌套方差分析测试了水年，土地所有权和区域对植物面积和生产力的影响。对于圣华金河谷，我们探索了水年与供水之间的联系，并制定了支持管理决策的指标。MSS工厂区域地图基于Landsat物候指标的支持向量机分类（2017年地图总体准确性：89％）。利用种子产量的线性回归模型（n  = 68，R ^2）创建了ST生产力图 = 0.53，归一化RMSE = 10.5％）。2017年中部谷地的ST估计面积为32,369公顷（29,845–34,893公顷95％CI），WGSW的估计面积为13,012公顷（11,628–14,396公顷）。ST种子的平均产量范围从三角洲盆地的577千克/公顷到圣华金盆地的365千克/公顷。与正常水年相比，在关键干旱年份，WGSW面积和ST种子产量下降，而ST面积增加（Scheffe's检验，P  <0.05）。萨克拉曼多山谷的ST面积增加最大（〜75％）。在正常水年中，自愿供水量增加，而ST种子产量随供水量增加。žST种子产量的分数可用于评估湿地性能和辅助资源分配决策。更新的地图将支持未来几年的栖息地监测，保护规划和水管理，而随着气候变化，这些地方可能面临更大的水供应不确定性。