Data from: Identifying management actions to increase foraging opportunities for shorebirds at semi-intensive shrimp-farms

The expansion of aquaculture has resulted in widespread habitat conversion throughout the world. Identifying beneficial management measures may dramatically reduce negative impacts of aquaculture for migratory birds. 2. We studied how densities of foraging shorebirds varied at ponds within a semi-intensive shrimp-aquaculture farm in northwestern coast of Mexico, as related to timing of harvest and tidal cycles. Further, we estimated the total daily available area for each shorebird species throughout two entire harvesting seasons at the shrimp-farm. 3. High densities (average ca. 50 ind·ha-1) of foraging shorebirds were found during the first days following pond harvest. The most abundant species were Willet (Tringa semipalmata) and Black-necked Stilt (Himantopus mexicanus), followed by Marbled Godwit (Limosa fedoa) and American Avocet (Recurvirostra americana). Other regular but less abundant species were Whimbrel (Numenius phaeopus) and dowitchers (Limnodromus spp.). 4. Densities of shorebirds sharply declined daily following harvest. In addition, the time-window availability of harvested ponds was related to each species’ foraging behavior: less than 2 days for godwits and dowitchers; 4 days for stilts; 5 days for willets; and more than a week for avocets and whimbrels. However, birds continued to use harvested ponds that received a low-but-continuous water influx. 5. Our results demonstrate that a tropical shrimp-farm represents a patchy environment that provides 4.3 to 12.7 % (depending on species) of its total area as foraging opportunities for shorebirds.'Synthesis and applications': Sequential harvesting of ponds and increasing moisture of the substrate by providing some water supply to harvested ponds, at least throughout the harvesting period, could integrate shorebird conservation into shrimp-farm production. These low-cost and easy management procedures would not increase costs or affect shrimp production -thus representing a win-win opportunity- and have potential applications for shorebird conservation throughout the world.水产养殖（aquaculture）的扩张已在全球范围内引发广泛的生境转换。识别高效的管理措施，可显著降低水产养殖对候鸟的负面影响。 2. 本研究以墨西哥西北海岸的一座半精养虾场（semi-intensive shrimp-aquaculture farm）内的养殖塘为研究对象，探究了觅食滨鸟的种群密度与收获时机及潮汐周期的关联；此外，我们还估算了该虾场两个完整收获季内，每种滨鸟每日可利用的总觅食面积。 3. 养殖塘收获后的最初几日，觅食滨鸟的种群密度极高（平均约50 个体·公顷⁻¹）。优势物种为长嘴鹬（Willet, Tringa semipalmata）与黑颈长脚鹬（Black-necked Stilt, Himantopus mexicanus），其次为斑尾塍鹬（Marbled Godwit, Limosa fedoa）与美洲反嘴鹬（American Avocet, Recurvirostra americana）；其他常见但密度较低的物种为中杓鹬（Whimbrel, Numenius phaeopus）及滨鹬类（dowitchers, Limnodromus spp.）。 4. 收获后，滨鸟的种群密度每日均呈显著下降趋势。此外，收获后养殖塘的可利用时长窗口与各物种的觅食行为密切相关：塍鹬类与滨鹬类的可利用时长不足2天，长脚鹬为4天，长嘴鹬为5天，反嘴鹬与中杓鹬则可超过1周。不过，仍有滨鸟持续利用那些持续获得少量补水的收获后养殖塘。 5. 本研究结果表明，热带虾场属于斑块状生境，可为滨鸟提供占其总面积4.3%至12.7%的觅食区域（具体比例因物种而异）。"综合与应用"：通过对收获后的养殖塘实施持续补水（至少在收获期内）以维持底质湿度，并采用分批收获养殖塘的管理方式，可将滨鸟保护工作融入虾场生产流程。此类低成本、易操作的管理措施既不会增加生产成本，也不会影响虾类养殖产量，实为双赢方案，且在全球范围内具备推广应用于滨鸟保护的潜力。