Abstract

Invasive species introduction and expansion is the second greatest threat to global biodiversity decline after habitat degradation. Introduced in the 1930s, the benthivorous Longnose Sucker (Catostomus catostomus) became established in Yellowstone Lake, Wyoming, USA, and used tributary streams for spawning. With this introduction, concerns were raised regarding their possible competition for food resources with native adfluvial Yellowstone Cutthroat Trout (Oncorhynchus clarkii bouvieri). Additionally, insufficient literature exists on Longnose Sucker feeding habits throughout their range, and there has been no comprehensive study of Longnose Sucker diet in Yellowstone Lake. The need exists for understanding the community ecology and food web dynamics in Yellowstone Lake, especially as non-native Lake Trout (Salvelinus namaycush) have caused declines in Yellowstone Cutthroat Trout through predation. The objectives of this study were to examine possible size-specific shifts in feeding habits, evaluate feeding strategy, and compare historical and contemporary diet data of Longnose Suckers in Yellowstone Lake. Diet data collected during summer of 2018 were analyzed by length-class to test for size-specific diet shifts. As Longnose Sucker length increased, copepods (Diacyclops bicuspidatus thomasi, Leptodiaptomus ashlandi or Hesperodiaptomus shoshone) decreased in proportion by weight. In contrast, dipterans (Chironomidae) and amphipods (Hyalella spp. or Gammarus spp.) varied in proportion by weight in the diet across length classes. We assessed the feeding strategy by evaluating the relationship between prey-specific abundance and percent frequency of occurrence. This assessment indicates that Longnose Suckers have a heterogeneous diet and generalized feeding strategy as all prey items had a prey-specific abundance value of <50%. Diet composition differed significantly between historical and contemporary samples, likely related to the differences in sampling locations and possibly due to a Lake Trout-induced trophic cascade. This study established the diet composition and feeding habits of Longnose Suckers residing in Yellowstone Lake, thus, expanding our knowledge of Longnose Sucker feeding patterns and ecology.

摘要

入侵物种的引进和扩展是生境退化之后对全球生物多样性下降的第二大威胁。弯曲的长鼻吸盘（Catostomus catostomus）于1930年代引进，在美国怀俄明州的黄石湖中建立，并使用支流进行产卵。通过此介绍，人们开始担心它们可能与原生的黄化残酷鳟鱼（Oncorhynchus clarkii bouvieri）争夺食物资源）。此外，关于长鼻吸盘的摄食习惯在其整个范围内的文献不足，并且尚未对黄石湖中的长鼻吸盘饮食进行全面研究。有必要了解黄石湖的社区生态和食物网的动态，特别是由于非本地鳟鱼（Salvelinus namaycush）通过捕食导致黄石Cut鳟的衰退。这项研究的目的是研究黄石湖中长鼻吸盘的进食习惯可能发生的大小变化，评估进食策略，并比较历史和当代饮食数据。按长度分类分析了2018年夏季收集的饮食数据，以测试特定大小的饮食变化。随着Longnose Sucker长度的增加，co足类（按重量计，双环线虫bicuspidatus thomasi，Leptodiaptomus ashlandi或Hesperodiaptomus shoshone的比例下降。相比之下，双足动物（Chironomidae）和两栖动物（Hyalella spp。或Gammarusspp。）在饮食中的重量比例因人而异。我们通过评估特定于猎物的丰度与发生百分比之间的关系来评估喂养策略。该评估表明，长鼻吸盘具有多样化的饮食和广泛的喂养策略，因为所有猎物的捕食特异性丰度值均小于50％。饮食组成在历史样本与当代样本之间存在显着差异，这可能与采样地点的差异有关，并且可能是由于鳟鱼所致的营养级联反应所致。这项研究建立了居住在黄石湖中的长鼻吸盘的饮食组成和喂养习惯，从而扩展了我们对长鼻吸盘喂养方式和生态学的认识。