Seabird disturbance monitoring

Seabirds are long-lived, upper trophic level predators that are integral components of marine ecosystems. Marine protected areas (MPAs) can provide both direct and indirect benefits to seabirds. Direct benefits involve reducing the direct interactions seabirds have with humans such as from fisheries and recreational activities. Indirect benefits involve reducing competition with humans for prey resources. As the abundance of prey increases within and adjacent to MPAs, seabirds may benefit as more abundant prey resources lead to increases in their productivity and population sizes. We monitored the populations of six coastally breeding marine bird species: four seabirds that feed largely on juvenile and other small fishes in nearshore habitats (Brandt’s cormorant, pelagic cormorant, double-crested cormorant, and pigeon guillemot), one seabird that feeds on both fish and intertidal invertebrates (western gull), and one shorebird that feeds primarily on rocky intertidal invertebrates (black oystercatcher). We collected data on baseline population size, productivity, foraging rates, and rates of human-caused disturbance inside and outside of three MPA clusters: Pyramid Point SMCA (Del Norte county); South Cape Mendocino SMR (Humboldt County); and Ten Mile SMR, MacKerricher SMCA, Point Cabrillo SMR, and Russian Gulch SMCA (Mendocino county). The long-term objectives of our monitoring are to 1) document how seabirds are using coastal and nearshore habitats in relation to a sample of newly established MPAs within the NCSR and 2) develop seabirds as tools to investigate changes in fish and invertebrate populations inside and outside of NCSR MPAs. Data presented here focus on baseline disturbance monitoring for both roosting and breeding seabirds as well as hauled out marine mammals.

海鸟为长寿命的顶级营养级捕食者，是海洋生态系统不可或缺的组成部分。海洋保护区（Marine Protected Areas, MPAs）可为海鸟提供直接与间接益处：直接益处为减少海鸟与人类的直接接触，例如渔业活动及休闲娱乐活动带来的干扰；间接益处为降低海鸟与人类在猎物资源上的竞争。随着海洋保护区及其毗邻海域的猎物丰度提升，海鸟将从中获益——更充足的猎物资源可提升其繁殖生产力与种群规模。
本研究对6种海岸繁殖海鸟与滨鸟的种群开展了监测：其中4种为主要在近岸生境以幼鱼及其他小型鱼类为食的海鸟，包括布兰德鸬鹚（Brandt’s cormorant）、远洋鸬鹚（pelagic cormorant）、双冠鸬鹚（double-crested cormorant）及鸽海雀（pigeon guillemot）；1种为兼食鱼类与潮间带无脊椎动物的海鸟——西美鸥（western gull）；剩余1种为主要以岩质潮间带无脊椎动物为食的滨鸟——黑蛎鹬（black oystercatcher）。
我们收集了3个海洋保护区集群内外的基线种群规模、繁殖生产力、觅食率及人为干扰率数据，所涉3个保护区集群分别为：德尔诺特县的金字塔点州立海洋保护区域（Pyramid Point SMCA）、洪堡县的南门多西诺角州立海洋保护区（South Cape Mendocino SMR），以及门多西诺县的十英里州立海洋保护区（Ten Mile SMR）、麦克基里州立海洋保护区域（MacKerricher SMCA）、卡布里洛角州立海洋保护区（Point Cabrillo SMR）与俄罗斯峡谷州立海洋保护区域（Russian Gulch SMCA）。
本次监测的长期目标有二：其一，记录海鸟对北海岸州立保护区（North Coast State Reserve, NCSR）内新建海洋保护区样本对应的海岸与近岸生境的利用模式；其二，将海鸟作为研究工具，探究北海岸州立保护区（NCSR）内外鱼类与无脊椎动物种群的动态变化。
本文呈现的数据聚焦于栖息与繁殖期海鸟以及上岸休憩的海洋哺乳动物的基线干扰监测工作。