School of Environmental and Forest Sciences, University of Washington, Seattle, Washington, United States of America.
Washington Sea Grant, University of Washington, Seattle, Washington, United States of America.
PLoS One. 2024 May 31;19(5):e0302518. doi: 10.1371/journal.pone.0302518. eCollection 2024.
Predation by invasive species can threaten local ecosystems and economies. The European green crab (Carcinus maenas), one of the most widespread marine invasive species, is an effective predator associated with clam and crab population declines outside of its native range. In the U.S. Pacific Northwest, green crab has recently increased in abundance and expanded its distribution, generating concern for estuarine ecosystems and associated aquaculture production. However, regionally-specific information on the trophic impacts of invasive green crab is very limited. We compared the stomach contents of green crabs collected on clam aquaculture beds versus intertidal sloughs in Willapa Bay, Washington, to provide the first in-depth description of European green crab diet at a particularly crucial time for regional management. We first identified putative prey items using DNA metabarcoding of stomach content samples. We compared diet composition across sites using prey presence/absence and an index of species-specific relative abundance. For eight prey species, we also calibrated metabarcoding data to quantitatively compare DNA abundance between prey taxa, and to describe an 'average' green crab diet at an intertidal slough versus a clam aquaculture bed. From the stomach contents of 61 green crabs, we identified 54 unique taxa belonging to nine phyla. The stomach contents of crabs collected from clam aquaculture beds were significantly different from the stomach contents of crabs collected at intertidal sloughs. Across all sites, arthropods were the most frequently detected prey, with the native hairy shore crab (Hemigrapsus oregonensis) the single most common prey item. Of the eight species calibrated with a quantitative model, two ecologically-important native species-the sand shrimp (Crangon franciscorum) and the Pacific staghorn sculpin (Leptocottus armatus)-had the highest average DNA abundance when detected in a stomach content sample. In addition to providing timely information on green crab diet, our research demonstrates the novel application of a recently developed model for more quantitative DNA metabarcoding. This represents another step in the ongoing evolution of DNA-based diet analysis towards producing the quantitative data necessary for modeling invasive species impacts.
捕食性入侵物种可能会威胁到当地的生态系统和经济。欧洲绿蟹（Carcinus maenas）是分布最广泛的海洋入侵物种之一，它是一种有效的捕食者，与原产范围外的蛤和蟹种群减少有关。在美国太平洋西北地区，绿蟹的数量最近有所增加，分布范围也有所扩大，这引起了人们对河口生态系统和相关水产养殖生产的担忧。然而，关于入侵绿蟹的营养影响的区域性具体信息非常有限。我们比较了在华盛顿威拉帕湾的蛤养殖床上和潮间带沼泽中采集的绿蟹的胃内容物，以提供有关该地区管理至关重要时期的欧洲绿蟹饮食的第一手深入描述。我们首先使用胃内容物样本的 DNA metabarcoding 来识别可能的猎物。我们通过猎物的存在/不存在以及特定物种相对丰度的指数来比较不同地点的饮食组成。对于八种猎物，我们还校准了 metabarcoding 数据，以定量比较猎物分类群之间的 DNA 丰度，并描述潮间带沼泽和蛤养殖床之间的“平均”绿蟹饮食。从 61 只绿蟹的胃内容物中，我们鉴定出属于 9 个门的 54 个独特分类群。从蛤养殖床采集的绿蟹胃内容物与从潮间带沼泽采集的绿蟹胃内容物有显著差异。在所有地点，节肢动物是最常检测到的猎物，其中本地多毛岸蟹（Hemigrapsus oregonensis）是最常见的猎物。在所校准的 8 种定量模型的物种中，两种具有生态重要性的本地物种——沙虾（Crangon franciscorum）和太平洋鹿角石斑鱼（Leptocottus armatus）——在胃内容物样本中检测到的平均 DNA 丰度最高。除了提供有关绿蟹饮食的及时信息外，我们的研究还展示了最近开发的用于更定量 DNA metabarcoding 的新型应用。这代表了基于 DNA 的饮食分析朝着产生用于模拟入侵物种影响的定量数据的方向发展的另一个步骤。
