Minder Mario, Arsenault Emily R, Pyron Mark, Otgonganbat Amarbat, Mendsaikhan Bud
Department of Biology Ball State University Muncie Indiana USA.
Kansas Biological Survey and Department of Ecology and Evolutionary Biology University of Kansas Lawrence Kansas USA.
Ecol Evol. 2023 May 21;13(5):e10132. doi: 10.1002/ece3.10132. eCollection 2023 May.
Lotic systems in mountain regions have historically provided secure habitat for native fish populations because of their relative isolation from human settlement and lack of upstream disturbances. However, rivers of mountain ecoregions are currently experiencing heightened levels of disturbance due to the introduction of nonnative species impacting endemic fishes in these areas. We compared the fish assemblages and diets of mountain steppe fishes of the stocked rivers in Wyoming with rivers in northern Mongolia where stocking is absent. Using gut content analysis, we quantified the selectivity and diets of fishes collected in these systems. Nonnative species had more generalist diets with lower levels of selectivity than most native species and native species had high levels of dietary specificity and selectivity. High abundances of nonnative species and high levels of dietary overlaps in our Wyoming sites is a cause of concern for native Cutthroat Trout and overall system stability. In contrast, fish assemblages characterizing Mongolia mountain steppe rivers were composed of only native species with diverse diets and higher selectivity values, suggesting low probability for interspecific competition.
由于山区流水系统相对远离人类定居点且缺乏上游干扰，历史上一直为本地鱼类种群提供安全的栖息地。然而，由于引入非本地物种影响了这些地区的特有鱼类，山区生态区域的河流目前正经历着更高程度的干扰。我们将怀俄明州有鱼类放养河流的山区草原鱼类群落和食性与蒙古北部无鱼类放养的河流进行了比较。通过肠道内容物分析，我们量化了在这些系统中采集的鱼类的选择性和食性。非本地物种的食性更具通用性，选择性水平低于大多数本地物种，而本地物种具有较高的食性特异性和选择性。我们在怀俄明州的研究地点中非本地物种的高丰度和高食性重叠，是本地割喉鳟鱼和整个系统稳定性令人担忧的一个原因。相比之下，蒙古山区草原河流的鱼类群落仅由食性多样且选择性值较高的本地物种组成，这表明种间竞争的可能性较低。
