4.2 Aquatic Communities
Climate Impacts . Increased air temperatures may lead to increased water temperatures and potentially lower DO levels. Stream swamp communities experience periodic tempera- ture increases and DO decreases that may be exacerbated by changing climate conditions. Higher air and water temperatures can also lead to increased evaporation, which results in less fowing water available for aquatic species to use. Hot spells can have the same efect as overall increased air temperatures but on a much more acute scale. According to DeWan et al. (2010) , hydrologic regimes in the Coastal Plain are likely to be much more sensitive to changes in precipitation than to changes in temperature. Potential changes in the amounts and timing of precipitation have numerous and varied efects. Decreases in overall summer precipitation will likely cause reduced water fows, which will further contribute to warmer water temperatures and stress water quality. Tis is particu- larly important in the context of seasonal droughts, because nutrients may become concen- trated and fush out of systems more slowly during low fow periods. Severe and prolonged droughts may decrease streamfow, decrease groundwater recharge, and increase evapora- tion, resulting in impacts to streams of this theme. Additionally, upstream headwaters and other small streams contributing fow to stream swamp communities could dry up, posing potential impacts to aquatic species and downstream fow regimes (DeWan et al. 2010; Karl et al. 2009; Holman et al. 2010) . Increased storm intensity can lead to fooding and increased stormwater runof and erosion. With increased stormwater runof there is also an increase in sediments, nutri- ents, and contaminants loading into streams and potential negative efects on biota. Te increased loads could afect water quality and habitat for aquatic species, as well as drink- ing water for municipalities. Stormwater controls and retrofts will become increasingly important (Band and Salvesen 2009) . With a change in intensity and variability of rainfall, there are potential changes to stream fow patterns, channel hydrodynamics, lake levels, and the volume of groundwater from aquifers (Band and Salvesen 2009; Holman et al. 2010; Bakke 2008) . Channel hydrodynamics include fow regime, sediment transport, and overall channel design and can be altered by changes in storm frequency and intensity. Some streams in this aquatic system have a pattern of rifes, runs, and pools, and will exhibit overall changes to the quantity and quality of these habitats. Other streams and swamps have rel- atively slack water and comparatively few rifes and runs and they may exhibit a shifting of sand bars. Storms may cause the felling of riparian trees, particularly in areas with narrow riparian areas. Increased woody debris in these streams will alter channel hydrodynamics as well as available habitat. An increase in the number of tropical events can lead to fash fooding, which causes many of the above-mentioned responses. Efects such as increased sediments and con- taminants into aquatic systems, in addition to major disruption to channel design and
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2015 NC Wildlife Action Plan
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