河流生境的评估方法及应用的研究进展

河流生境是水生生物赖以生存的物理、化学和生物环境的综合体,是河流生态系统的重要组成部分。河流生境评价有助于掌握河流的生态健康状况,识别河流退化的原因,为河流的生态修复提供依据。文章梳理总结了20世纪80年代至2018年文献中报道的全球范围内河流生境评估的方法,然后根据每种方法的侧重点和目标,将它们分为预测模型法和多指标综合评估法两种类型,并比较了它们各自的优势和不足。预测模型法适于长期的生境动态监测,但该方法需要以自然无干扰的河流为参照,并且需要大量历史数据,统一评估不易实现;多指标综合评估法评估相对快速方便,但评估过程复杂,且评价标准不一,结果有一定的局限性。这些方法的适用范围从中小型的可涉水河流到较大的不可涉水河流,但适用于大型不可涉水河流的生境评估方法和案例非常有限。通过分类整理,发现我国河流生境评估方法多是参考国外几种常用的河流评估方法,种类单一,而且多是针对个别河流,并且未对这些河流所在的流域的生境状况进行深入研究,广适性较差。因此,文章从以下几个方面对我国河流生境评估体系的发展提出几点建议:(1)确定科学和标准化的评分指标,因地制宜,以满足不同河流特征;(2)扩大评估范围,从流域和景观尺度开展生境监测,关注全流域的健康状况;(3)扩大时间尺度,建立模型,进行长期的动态评估;(4)鼓励政府宏观规划,促进不同管理部门间的合作,整合不同地区的河流生境数据并建立国家尺度的河流生境大数据库,以实现我国河流生态健康的维护和流域的可持续发展。

A REVIEW OF RIVER HABITAT ASSESSMENTS AND APPLICATIONS

River habitat is the integration of physical, chemical, and biological conditions that river organisms rely on, and is an important part of river ecosystems. Assessments of river habitat can help understand river ecological health condition, identify causes of habitat degradation, and provide clues and solutions for river ecological restorations. We reviewed river habitat assessment methods and applications from the global literature pool that published between the 1980s and 2018. According to their focuses and objectives, these methods were divided into two types: predictive model and multi-variable assessment method. We then compared advantages and disadvantages of these methods. The predictive model method is suitable for monitoring long-term habitat dynamics, but it needs to take natural undisturbed rivers as a reference and requires a large amount of historical data. This method is not easy to be developed and applied in a nationwide scale. The multi-variable assessment method is rapid and convenient, but its evaluating process is relatively complex and the evaluation criteria are different by regions, so the findings may have some limitations. We also summarized and classified these methods into the ones suitable for small and medium wadeable streams and the ones suitable for large non-wadeable rivers where the latter is less developed. Most of the current river habitat assessment applications in Chinese rivers are developed and modified from one or two most commonly used ones in other countries. Moreover, those applications and modifications are individual river-based, and the habitat conditions of these river basins have not been well studied. Thus, we suggest the following approaches to further develop habitat assessment methods for Chinese rivers to reach sustainable river basin management: (1) determine more scientific and standardized scoring indicators and meet the characteristics of different rivers according to their local conditions; (2) expand the scope of assessments, conduct habitat monitoring from watershed and landscape scale, and pay attention to the health status of the whole river basin; (3) expand the time scale, establish models and conduct long-term dynamic evaluations; and (4) encourage the government to initiate large scale planning and collaborations among management agencies, and to integrate region-based habitat data and establish the nationwide river habitat mega database.