Type of habitat alteration Location Effects
Blockage by dam/
habitat fragmentation
Tocuri dam, tocantins river, Brazil Interrupted upstream, reproductive migration of long distance migratory species; population of these species were negatively affected in lower Tocantins, downstream of dams [33].
Upper Volga river, Russian Federation Change to fish fauna following construction of  four major reservoir; 7 species (mainly anadromous rhcophils) disappeared, and more of these 9 are reproducing naturally and will probably disapared when stocking is discontinued [34].
Habitat simplification Upper Volga river, Russian Fedration,
River Rhine, Lower Rhhone river, Europe
Limited bio productivity in reservoirs because of considerable changes “typical riverine fish habitat remain only in the upper reaches of tributaries and in the forewater of dams and account for no more than 1% of the total water surface area”[34].
Unnatural discharge regimes Colorado river, USA Elimination of 2 year classes of endemic Colorado squawfish from its most productive remaining nursery habitats in the Green River Catch, perhaps because extreme flow fluctuating and alteration of seasonal flow regimes [35-36].
Table 3: Examples of world -wide biodiversity impact from habitat alteration resulting from hydrological development [24].
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