Bioindicators Enhance Stream Assessment: Physicochemical Parameters’ Effect on Salamander Abundance

Ecological restoration has emerged as a critical tool for addressing ecosystem degradation worldwide. The Stream Quantification Tool (SQT) represents a significant advancement in stream restoration methodology, providing a standardized framework for quantifying stream functions and evaluating project outcomes. We investigated relationships between salamander abundance and physicochemical parameters from the SQT (nitrogen, turbidity, temperature, and composite SQT physicochemical score) across 16 streams in the upstate region of South Carolina. Stream salamanders can be reliable bioindicators due to their philopatric nature, longevity, and stable populations, making them valuable for assessing stream restoration effectiveness. Six salamander species (n=394 individuals) were identified across 14 streams where salamanders were present. N-mixture models were used to analyze abundance patterns while accounting for imperfect detection. Turbidity was the strongest negative predictor of salamander abundance, followed by nitrogen. Removal of an agriculturally impacted stream with elevated turbidity substantially altered model rankings, making the null model top-ranked, followed by nitrogen, composite physicochemical score, and temperature. These findings demonstrate turbidity’s critical role in salamander abundance. Management practices should prioritize erosion and sediment control solutions for salamander conservation. For SQT biological monitoring, we recommend focusing on turbidity and nitrogen as key parameters affecting salamander abundance in stream assessments.

生态修复已成为全球范围内应对生态系统退化的关键手段。溪流量化工具（Stream Quantification Tool, SQT）是溪流修复方法论领域的一项重大进展，其提供了一套标准化框架，用于量化溪流生态系统功能并评估修复项目成效。我们对南卡罗来纳州北部地区的16条溪流展开研究，分析了采用SQT测得的理化参数（包括氮、浊度、温度以及SQT综合理化评分）与蝾螈种群丰度之间的关联。溪流蝾螈因具有恋巢习性、寿命较长且种群稳定的特点，可作为可靠的生物指示物种，因而在评估溪流修复成效方面具有重要价值。在存在蝾螈的14条溪流中，共鉴定出6种蝾螈，样本个体总数达394只。研究采用N混合模型分析种群丰度分布模式，并同时校正了检测不完全的问题。浊度是对蝾螈种群丰度影响最强的负向预测因子，其次为氮含量。移除一条受农业活动影响且浊度升高的溪流后，模型排名发生了显著变化：零模型跃居首位，其后依次为氮含量、综合理化评分与温度。上述研究结果证实了浊度对蝾螈种群丰度的关键影响。在蝾螈保护工作中，相关管理实践应优先考虑水土流失与沉积物控制方案。在采用SQT开展生物监测时，我们建议在溪流生态评估中重点关注浊度与氮含量这两个影响蝾螈种群丰度的关键参数。