Horvath Elena K, Christensen Jay R, Mehaffey Megan H, Neale Anne C
US EPA, Office of Research and Development, Oak Ridge Institute for Science and Education, Research Triangle Park, Durham, NC, USA.
US EPA, Office of Research and Development, National Exposure Research Laboratory, Las Vegas, NV, USA.
Ecol Indic. 2017;83:462-473. doi: 10.1016/j.ecolind.2017.07.026.
Wetlands provide key functions in the landscape from improving water quality, to regulating flows, to providing wildlife habitat. Over half of the wetlands in the contiguous United States (CONUS) have been converted to agricultural and urban land uses. However, over the last several decades, research has shown the benefits of wetlands to hydrologic, chemical, biological processes, spurring the creation of government programs and private initiatives to restore wetlands. Initiatives tend to focus on individual wetland creation, yet the greatest benefits are achieved when strategic restoration planning occurs across a watershed or multiple watersheds. For watershed-level wetland restoration planning to occur, informative data layers on potential wetland areas are needed. We created an indicator of potential wetland areas (PWA), using nationally available datasets to identify characteristics that could support wetland ecosystems, including: poorly drained soils and low-relief landscape positions as indicated by a derived topographic data layer. We compared our PWA with the National Wetlands Inventory (NWI) from 11 states throughout the CONUS to evaluate their alignment. The state-level percentage of NWI-designated wetlands directly overlapping the PWA ranged from 39 to 95%. When we included NWI that was immediately adjacent to the overlapping NWI, our range of correspondence to NWI ranged from 60 to 99%. Wetland restoration is more likely on certain landscapes (e.g., agriculture) than others due to the lack of substantive infrastructure and the potential for the restoration of hydrology; therefore, we combined the National Land Cover Dataset (NLCD) with the PWA to identify potentially restorable wetlands on agricultural land (PRW-Ag). The PRW-Ag identified a total of over 46 million ha with the potential to support wetlands. The largest concentrations of PRW-Ag occurred in the glaciated corn belt of the upper Mississippi River from Ohio to the Dakotas and in the Mississippi Alluvial Valley. The PRW-Ag layer could assist land managers in identifying sites that may qualify for enrollment in conservation programs, where planners can coordinate restoration efforts, or where decision makers can target resources to optimize the services provided across a watershed or multiple watersheds.
湿地在景观中发挥着关键作用，从改善水质到调节水流，再到提供野生动物栖息地。美国本土（CONUS）超过一半的湿地已被转变为农业和城市用地。然而，在过去几十年里，研究表明湿地对水文、化学和生物过程有益，这促使政府制定相关计划以及私人发起相关倡议来恢复湿地。这些倡议往往侧重于单个湿地的创建，但当在一个流域或多个流域进行战略恢复规划时，能获得最大的效益。为了进行流域层面的湿地恢复规划，需要有关潜在湿地面积的信息数据层。我们利用全国可用数据集创建了一个潜在湿地面积（PWA）指标，以识别能够支持湿地生态系统的特征，包括：排水不良的土壤以及由派生地形数据层显示的低起伏地貌位置。我们将我们的PWA与来自美国本土11个州的国家湿地清单（NWI）进行比较，以评估它们的一致性。NWI指定的湿地与PWA直接重叠的州级百分比范围为39%至95%。当我们将紧邻重叠NWI的NWI也包括在内时，我们与NWI的对应范围为60%至99%。由于缺乏实质性基础设施以及水文恢复的潜力，湿地恢复在某些景观（如农业景观）上比其他景观更有可能实现；因此，我们将国家土地覆盖数据集（NLCD）与PWA相结合，以识别农业用地上潜在可恢复的湿地（PRW-Ag）。PRW-Ag识别出总计超过4600万公顷具有支持湿地潜力的土地。PRW-Ag的最大集中区域出现在从俄亥俄州到北达科他州的密西西比河上游冰川玉米带以及密西西比河冲积平原。PRW-Ag图层可以帮助土地管理者识别可能符合纳入保护计划条件的地点，规划者可以在这些地点协调恢复工作，或者决策者可以将资源集中于这些地点，以优化跨一个流域或多个流域提供的服务。
