Meteorology and species composition of plant communities, birds and fishes before and after initial impoundment of Miharu Dam Reservoir, Japan

Abstract

The immediate impact of damming appears most notably at the first filling of water, when the dam blocks the river and a lake suddenly forms. In this review, the changes in meteorology, plant communities, birds and fishes surrounding initial impoundment of Miharu Dam, constructed in an Asian Monsoon region, are summarised based on previous papers and subsequent field research. Although wind and temperature changes were investigated, land and lake wind occur due to the different thermal properties between the land and lake, and this type of wind often occurs at large lakes such as Glen Canyon Dam Reservoir or Lake Biwa. The size of Miharu Dam Reservoir (ponding area 2.9 km 2 ) was insufficient to cause landlake air differentials. Therefore, wind direction and air temperature were unaffected. Mountain winds weakened at the lake centre and near the dam body. Changes in vegetation were especially diverse at the drawdown zone (the slopes above and below the normal water level). On slopes above this zone, trees died and species composition changed due to submergence. Within the drawdown zone, the pre-existing plant community disappeared, and floodresistant plants such as Salix subfragilis increased. The natatorial bird population continued to grow for 4 years after dam reservoir emergence and stabilised thereafter. Every year, the majority of natatorial birds utilising the dam reservoir as a resting area were ducks, but populations of diving ducks fluctuated depending on water level and iced area. After impoundment, the fish populations increased. As in most dam reservoirs in Japan, populations of invasive fish species such as Micropterus salmoides and Lepomis macrochirus increased. However, spawning grounds dried up during low-water-level seasons, suggesting that regulating water levels may help reduce invasive species.

The Effects of Edaphic Factors on Riparian Plants in the Middle and Lower Reaches of the Hanjiang River, China

“…Plants 2022, 11, 531 9 of 14 However, the formation and maintenance of plant communities in the riparian zones is the result of synergy between edaphic factors and long-term accumulation [42,43]. In particular, direct modification of the natural environment by anthropogenic activities, such as the increasing number of cascade dams, will result in a reduction in riparian area and a reduction in living space for emergent water plants and moist plants in this zone [44,45]. As the study only indirectly discussed the effect of soil on plants in the riparian zones, future investigations will combine other factors, such as the influence of anthropogenic activities, with the composition of plants in the MLHR to identify the mechanism of community maintenance and succession.…”

Potential effects of dam cascade on fish: lessons from the Yangtze River

“…The effects of individual dams on fish diversity have been studied extensively and are now relatively well understood (López-Pujol and Ren 2009;Young et al 2011;Azami et al 2012). Nevertheless, economic growth in many regions of the world is spurring demand for renewable energy sources, leading to the construction of many additional hydroelectric dams.…”

Biological Invasions in Fresh Waters: Micropterus salmoides, an American Fish Conquering the World

“…Predominantly warm [33][34][35][36][37][38], eutrophic [21,[39][40][41][42], and lentic [9,37,[43][44][45] waters. Submerged plants [9,19,21,33,[45][46][47][48][49][50][51][52][53][54][55][56][57][58][59][60][61], woody debris, or underwater structures [48,[62][63][64][65][66].…”

“…In South Korea and southern Africa, the introduction and spread of M. salmoides and other invasive species have been linked to anthropogenic alterations to rivers, including the construction of impoundments and large dams, where exotic species recovered better than the native fauna [94,156]. In many other ecosystems, M. salmoides occurrence was greater in (or restricted to) sites influenced by dams [13,37,190]. Indeed, largemouth bass do not tolerate high flow conditions [75], as they are easily flushed out, or the intermittent conditions that are typical of Mediterranean streams [45].…”