Navajo Sedge Inventory at Natural Bridges National Monument - Open Format Dataset (sensitive version)

Hanging gardens are an important part of the landscape at Natural Bridges National Monument (NABR) and are the most common type of spring within the park. These hanging gardens support a diversity of plant species including the federally listed threatened Navajo Sedge (Carex specuicola; CASP). CASP is confined to seep and spring emergences in sandstone outcroppings in the Four Corners area. Populations of CASP are known throughout northern Arizona and in southern Utah just south of NABR. Much of the potential habitat in southern Utah has not been surveyed for the species. Occurrences of CASP within NABR are at the northernmost extent of CASP’s range in the region and are also unique because they are in a canyon that is tributary to the Colorado River rather than the San Juan River. Since the extent of CASP populations were largely unknown, the objective of this project was to conduct a follow up inventory for CASP at hanging gardens in NABR to document occurrences of this species at NABR, its presence and absence in suitable habitat, and suggest sites to be incorporated into the regional monitoring program. Sites with positive occurrence of CASP could be targeted for increased protection by the park. Knowledge of these sites may also be used to advocate for management decisions such as the protection of water resources that recharge the springs of CASP habitat. This project resurveyed 64 previously known hanging gardens for CASP and documented and surveyed 26 new seeps found near the existing sites.

悬挂花园是天然桥国家纪念地（Natural Bridges National Monument，缩写NABR）景观的重要组成部分，同时也是园区内最常见的泉眼类型。这类悬挂花园孕育了多样的植物类群，其中包括联邦名录中列为受威胁物种的纳沃伊薹草（Navajo Sedge，学名*Carex specuicola*，缩写CASP）。CASP仅分布于四角地区砂岩露头处的渗流区与泉眼露头地带。目前已知CASP的种群分布于亚利桑那州北部，以及紧邻NABR以南的犹他州南部区域。犹他州南部大部分潜在栖息地尚未针对该物种开展调查。NABR境内的CASP分布点处于该物种在本区域分布范围的最北端，同时其分布位置也具有独特性——这些种群位于科罗拉多河的支流峡谷中，而非圣胡安河沿岸。由于此前对CASP的种群分布范围知之甚少，本项目的目标是对NABR内的悬挂花园开展CASP跟踪清查，以记录该物种在纪念地内的分布情况、其在适宜栖息地中的存在与缺失状况，并提出可纳入区域监测计划的候选地点。对于发现CASP的分布点位，园区可针对性地加强保护措施。掌握这些点位的信息也可用于推动相关管理决策，例如保护为CASP栖息地泉眼补给水源的水资源。本项目对64处此前已记录的悬挂花园开展了CASP复查，并对现有点位附近新发现的26处渗流区进行了记录与调查。