**1. Introduction**

It is a well-known fact that about 60% of the total global freshwater within our planet is confined to about 263 rivers within 145 countries, making up around 40% of the global population [1].

Unlike the Middle East, aquatic plants have gotten much more scientific attention, for planning and managing various water bodies in Europe and states. Lower plants (macrophytes and microphytes) have been widely used as ecological indicators in various parts of the world, also for the conservation and protection of natural resources as well as biodiversity [2–4].

The impacts of the continuous establishment of large dams on inland waters had become quite evident all over the world, as their total number approached 50,000 dams between 1950 and 2017 (a tenfold increase) when the number was only 5000

dams 60 years ago, whereas the total global irrigated area has only doubled, as it raised to around 280 million hectares only [5, 6].

Key climatic and non-climatic parameters affecting the distribution and abundance of aquatic lower plants, in both running and standing water bodies, have been thoroughly reviewed by [7]. They explained their potential role and application, to point out indicators for expected ecological changes in any natural ecosystem [8]. Aquatic plant studies with respect to concerning environmental impacts have been mainly confined to flowering plants [9, 10], whereas lower plants (ferns, mosses, and even algae) had obtained little attention and were poorly dealt with for environmental monitoring [11]. Higher plants rather than lower ones have been much more widely applied as criteria for any environmental changes or pollution [10].

The distribution and abundance of aquatic plants, in general, depend on three main factors, which are biogeography, climatic mainly (hydrology and temperature), and geomorphology [7]. Eutrophication, on the other hand, is known to cause an intense shading by phytoplankton and filamentous algae in inland water bodies that result in the decline of aquatic plants [12, 13].

Using aquatic lower plants as an environmental monitoring tool because of their sensitivity to any ecological changes has been the concern of many scientists all over the world [7, 11, 14, 15]. Lower plant species in general have been used as a reliable indicator of any environmental impact or changes. However, almost all studies ended up with around (50) criteria for ecological indicators that have been formulated throughout four sets of parameters. In 1998, Mc geoch had adapted all to only nine. This finally ends up with seven criteria for climatic and no climatic impact in any ecosystem. Almost all published articles books and websites up to 2018 were summarized and tabulated [14, 15]. However, out of the total published papers in this respect none were from Iraq or Kurdistan and only (17) were from Asia [14].
