中小河流鱼类生境适宜性评估模型与等级分区

以浙江省龙游县社阳溪厚唇光唇鱼为代表性鱼类,通过2017—2020 年现场鱼类群落与生境影响因子调查,采用广义可加(GAM)模型和栖息地适宜性指数(HSI)模型,构建了社阳溪厚唇光唇鱼生境适宜性评估模型,并分析其生境适宜性阈值范围及分区。结果表明:采用GAM 赋权的算术平均算法(AMM)具有最好的模型拟合度,流速、水深及叶绿素a 的质量浓度是生境适宜性指数模型的关键解释变量,其偏差贡献率分别为61. 5%、21. 0% 和12.5%。厚唇光唇鱼最适宜流速为37 ~58 cm/ s,最适宜水深为40 ~63 cm,最适宜叶绿素a 质量浓度为0. 10 ~0. 35 mg/ m3。厚唇光唇鱼生境分区具有较强的时空差异性,在空间上,最适宜生境主要分布在中下游河段;在时间上,2019—2020 年生境适宜度明显变差。

Habitat suitability assessment model and suitability grading classification for fishes in small and medium rivers

Taking the acrossocheilus labiatus in the Sheyang River of Longyou County, Zhejiang Province as the representative fish, a habitat suitability model was established by using GAM and HSI models through the investigation of fish communities and possible habitat impact factors in the field from 2017 to 2020. The habitat suitability zoning and threshold range were analyzed. The results show that the arithmetic mean algorithm (AMM) for weighting GAM models has the best model fitness. Flow rate, chlorophyll a and water depth are the key explanatory variables of the habitat suitability index model, and their deviation contribution rates are 61.5%, 21.0% and 12.5%, respectively. The optimum flow rate is from 37 to 58 cm/ s, the optimum water depth is from 40 to 63 cm, and the optimum chlorophyll a is from 0. 10 to 0. 35 mg/ m3. The habitat zoning of the acrossocheilus labiatus has strong spatial-temporal differences. The optimum habitat is mainly distributed in the upper and middle reaches of the river while the habitat suitability significantly deteriorated in 2019 and 2020.