An assessment of structural attributes and ecosystem function in restored Virginia coalfield streams

Abstract

As human populations continue to grow, expanding energy needs enhance freshwater resource conservation challenges. Mining for coal has significantly altered the landscape in the United States' Appalachian region, with significant negative effects on downstream water quality and ecosystem function. With recent policy changes concerning the impacts of coal mining on aquatic ecosystems, many coal companies choose to restore sections of stream located on older coal mining areas as mandated compensatory mitigation for mining-related stream disturbances. We assessed such mitigation using measures of both structure and function in restored and unrestored streams affected by surface mining operations. Macroinvertebrate assemblages in streams affected by older mining and recent restoration practices were rated as ''stressed'' and ''severely stressed,'' with streams varying from fair to optimal in terms of habitat. All streams were net heterotrophic with varying levels of ammonium uptake. No site differences were found for any measured physicochemical or functional variables, while invertebrate community metric scores were higher in unrestored streams. There were also no significant relationships found between structural and functional measurements in these streams. Principal components analysis implicated the importance of measuring physicochemical, structural, and functional variables in further analyses of restoration success. This study was unable to document pre-disturbance conditions, and as a result, we were unable to find evidence that restoration is currently having a significant effect on ecosystem processes within these systems. Further research is needed to understand the changes in ecosystem structure and function that come with time.

Nutrient Retention in Restored Streams and Rivers: A Global Review and Synthesis

“…In contrast, another study of AMD remediated streams found no site differences for any measured physicochemical or functional variables [73]. Likewise, a seasonal analysis showed no differences between restored and unrestored streams during the winter [73].…”

“…One study of AMD stream remediation showed increased NH 4 + uptake, reduced NO 3´u ptake to undetectable level, and increased SRP uptake to near normal rates [83]. In contrast, another study of AMD remediated streams found no site differences for any measured physicochemical or functional variables [73]. Likewise, a seasonal analysis showed no differences between restored and unrestored streams during the winter [73].…”

“…Some studies injected a single nutrient while others injected multiple nutrients. There were 66 single ammonium injections [59,[72][73][74], 45 single nitrate injections [30,[75][76][77][78], 38 combined ammonium and phosphate experiments [79,80], 59 combined nitrate and phosphate experiments [29,81], and 30 combined ammonium, nitrate and phosphate experiments [82,83]. Based on the type of nutrient injection, the total number of experiments was 134 ammonium, 134 nitrate, and 127 phosphate injections.…”

“…Some of the lowest nutrient uptake velocity rates in restored streams were in watersheds receiving acid mine drainage (AMD) from coal mines [73,83]. In the United States, coal companies are mandated to complete compensatory mitigation for mining related watershed disturbances and many choose to restore sections of stream in older coal mining areas [73].…”

“…In the United States, coal companies are mandated to complete compensatory mitigation for mining related watershed disturbances and many choose to restore sections of stream in older coal mining areas [73]. One study of AMD stream remediation showed increased NH 4 + uptake, reduced NO 3´u ptake to undetectable level, and increased SRP uptake to near normal rates [83].…”