This study presents an analysis of health status for aquatic ecoregions in the Heihe River Basin,a typical example of inland river basin in arid areas of northwest China.The basin was divided into eight aquatic ecoregions according to their aquatic ecological function regionalization at watershed scale.To evaluate water basin ecological health condition,a 13-indicator system was established based on "pressure-state-response"(PSR) model.The results shows that upstream area presents relatively good condition of ecological health,followed by middle reaches and downstream reaches,while middle and lower reaches presents extremely poor health condition.The reasons include that the upstream region receives the lowest external pollution and artificial disturbance,while middle area is influenced by relatively large population densities and intense agricultural activities.The middle and lower reaches are located in the desert region without rivers and reservoirs.Although the downstream region has lower population and fewer external contamination,the relatively insufficient influent and fragile water ecosystem habitat conditions lead to a poorer hydrobiology habitat security in this area.%本文以我国西北干旱区典型内陆河流域—黑河流域为例,基于黑河流域水生态区划,以“压力-状态-响应”(PSR)模型为基础,构建了涵盖13个指标的流域水生态健康评价体系,分析评价了流域内8个水生态区的健康状况.评价表明:黑河流域水生态区中,上游区域水生态健康状况较好,中游次之,中下游极差,下游较差.主要是因为上游地区受到外在污染最轻、人为扰动相对最小;中游地区人口密度相对较大,农业活动等外在扰动相对较多;中下游地区处于荒漠地区,河流、湖库等水体缺乏;而下游地区虽然人口数量少、水体受外来污染影响较小,流域水生态健康性压力相对较轻,但来水量相对不足、水生态系统栖息地条件极为脆弱,致使水生生物栖息地安全状况较差.
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