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Federal Register / Vol. 86, No. 109 / Wednesday, June 9, 2021 / Rules and Regulations
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burrow Unger et al. 2020, pp. 121122
and leaving them more exposed e.g., to predation. Excess sedimentation influences nest site selection and reduces habitat availability Guy et al.
2004, pp. 8082, 85 and is related to a reduction in current distribution of salamanders compared to historical occupancy of sites Quinn et al. 2013, pp. 78, 8182. Furthermore, the Carolina madtom is classified as an intolerant species according to the North Carolina Division of Water Resources NCDWR, meaning the species is most affected by environmental perturbations NCDWR
2013, p. 19. Fine sediments can influence the survival, distribution, and abundance of Neuse River waterdog by reducing the availability of food and cover, and hindering reproduction by smothering nests and eggs Braswell and Ashton 1985, p. 28.
All three of the river basins within the range of the Carolina madtom and Neuse River waterdog are affected by development, from an average of 7
percent in the Tar River basin to an average of 13 percent in the Neuse River basin based on the 2011 National Land Cover Data. The Neuse River basin contains one-sixth of the entire States human population, indicating heavy development pressure on the watershed.
The Middle Neuse MU contains 182
impaired stream miles, 9 major discharges, 272 minor discharges, and nearly 4,000 road crossings, all affecting the quality of the habitat for both species. The Middle Neuse is also 31
percent developed, with nearly 8
percent impervious surface, which changes natural streamflow, reduces appropriate stream habitat, and decreases water quality throughout the MU. For complete data on all of the populations, refer to appendices A and D of the SSA reports.
Agricultural Practices The main impacts to the Neuse River waterdog and Carolina madtom from agricultural practices occur from water pumping for irrigation and when best management practices BMPs for conservation are not followed, causing sedimentation, and nutrient and chemical pollution. Sedimentation can fill interstitial spaces of streambed substrates, altering habitat suitability of nesting and retreat sites for madtoms and waterdogs; it can coat leaf litter, diminishing or destroying waterdog foraging habitat; and it can smother and kill eggs. Sedimentation from agriculture has been linked to reduced body size in salamanders and other amphibians Gray 2002, pp. 2334, 48, 105; Gray et al. 2004, pp. 719, 727.

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Fertilizers and animal manure, which are both rich in nitrogen and phosphorus, are the primary sources of nutrient pollution from agricultural sources. Excess nutrients impact water quality when it rains or when water and soil containing nitrogen and phosphorus wash into nearby waters or leach into the water table or groundwater.
Confined animal feeding operations and feedlots can cause degradation of aquatic ecosystems and may cause direct effects to the species e.g., death resulting from hypoxia, primarily because of manure management issues.
Fertilized soils, manure, and livestock can be significant sources of nitrogenbased compounds like ammonia and nitrogen oxides. Ammonia can be harmful to aquatic life when concentrated in surface waters. For madtoms and waterdogs, excess ammonia can cause a number of problems, including alteration of metabolism, injury to gill tissue, and reduced growth rates. Extreme levels of ammonia can cause death.
Excessive water withdrawal or water withdrawal done illegally without the necessary permit, during dry times of year may cause impacts to the amount of water available to downstream sensitive areas during low flow months, resulting in dewatering of channels and displacement of fish and permanently aquatic salamanders, leading in turn to potential desiccation and death.
According to the 2011 National Land Cover Data, all of the watersheds within the range of the Carolina madtom and Neuse River waterdog are affected by agricultural land uses, most with 25
percent or more of the watershed having been converted for agricultural use.
Forest Management Silvicultural activities, when performed according to strict forest practices guidelines FPGs or BMPs, can retain adequate conditions for aquatic ecosystems; however, when FPGs/BMPs are not followed or if they fail, these practices can also contribute to the myriad of stressors facing aquatic systems in the Southeast, including North Carolina. Both smalland largescale clearing of forests have been shown to have a significant impact upon the physical, chemical, and biological characteristics of adjacent small streams Allan 1995, pp. 324327; Valente-Neto 2015, p. 116. Clearcutting and harvests in riparian systems can eliminate shade provided by forest canopies, exposing streams to more sunlight and increasing the instream water temperature Swift and Messer 1971, p. 111; Hewlett and Forston 1982, p. 983; GB Rishel 1982, p.
112; Lynch et al. 1984, p. 161; Allan
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1995, p. 325; Keim and Shoenholtz 1999, p. 197; Carroll et al. 2004, p. 275;
B.D. Clinton 2011, p. 979; Caldwell et al. 2014, p. 3. The increase in stream temperature and light after deforestation alters the macroinvertebrate and other aquatic species richness and abundance composition in streams Wenger 1999, p. 35; Caldwell et al. 2014, p. 3. As stated above, both the Neuse River waterdog and Carolina madtom are sensitive to changes in temperature, and sustained temperature increases will stress and possibly lead to mortality for these species.
Forestry activities can include the construction of logging roads through the riparian zone, and this can directly degrade nearby stream environments.
Roads can cause point-source pollution and sedimentation, as well as sedimentation traveling downstream into sensitive habitats. These effects lead to stress and mortality for both species, as discussed above under Development and Pollution, and as reported in studies of forestry-related sedimentation effects on survival of aquatic vertebrates Lowe et al. 2004, entire; Moseley et al. 2008, entire;
Peterman & Semlitsch 2009, entire.
While BMPs are presently widely adhered to, they were not always common practice, and implementation is not perfect. The most recent surveys of the Neuse and Tar-Pamlico River basins show that the average BMP
implementation rate is approximately 88 to 90 percent Coats 2017, p. 38.
Accordingly, while improper implementation is uncommon, failure to implement or inadequate implementation can have negative effects on sensitive aquatic species.
Further, the most recent assessment of forestry BMPs in North Carolina reported that improperly implemented BMPs associated with streamside management zones and stream crossings were frequently associated with risks to water quality Coats 2017, p. 9.
Invasive Species There are many areas across North Carolina where invasive species have invaded aquatic communities; are competing with native species for food, light, or breeding and nesting areas; and are impacting biodiversity. The flathead catfish Pylodictis olivaris is an invasive species that most likely impacts Carolina madtom distribution and may also have an impact on Neuse River waterdog distribution. The flathead catfish is an apex predator, known to influence native fish populations, including predation on benthic fishes, including madtoms, and
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