There have been long-lasting legacies of changes to the landscape and riverscape that are exceedingly well documented.
Catchment-scale activities such as agriculture, urbanization, forestry, mining, and other land uses influence catchment hydrology through the amount, quality, and timing of water and sediment discharges. One of the most pervasive alterations to freshwater is flow regulation, which affects the quantity, timing, and quality of water and sediments available to ecosystems, usually at great cost to the species living there (e.g., Arthington et al. 2010; Poff and Zimmerman 2010). Forest harvesting increases the rate at which water runs off into streams, resulting in larger peak flows and more erosive energy, which can both reduce the long-term storage and base-flow amounts of water (e.g., Moore and Wondzell
2005). It can also affect the channel’s structure and reduce potential habitat volume (Northcote and Hartman 2004; Sweeney et al. 2004). Agriculture and urbanization also affect patterns of flow and sediment discharges, especially through impervious surfaces that lead to high instantaneous peak flows (e.g., Chadwick et al. 2006). At the other extreme, natural low flows, exacerbated by high demands of humans for water for irrigation and domestic uses, can result in stranding of fishes with increased rates of mortality (Harvey et al. 2006; Grantham et al. 2012). This is also evident, for example, in stranding of fishes by dam operations that reduce flows too quickly for fishes to respond (Bradford et al. 2011). Lack of strategic plans to deal with low water supplies for all users, including aquatic ecosystems, will probably leave fishes as
a low priority despite the potentially long-term effects of local extinction.