Metabolic Variance: A Metric to Detect Shifts in Stream Ecosystem Function as a Result of Stream Restoration

Abstract

The restoration of lotic ecosystems as currently practiced is constrained by a limited understanding of the emergence of stream ecosystem functions and their linkages to perceived ecosystem services valued by society. An investigation was made into the connections between ecosystem function and hydraulic structure of a stream impacted by gravel mining operations in western New York. Stream ecosystem metabolic parameters were measured using two‐point dissolved oxygen diurnals on multiple reaches of the same stream, and were correlated with geomorphic and hydraulic descriptors of the same reaches. Results showed ecosystem metabolism at the reach scale varied as a function of geomorphic condition, where higher primary production and community respiration (CR) were observed for reaches observed to be unstable vs. those that were stable or restored. The metabolic variance of a stream ecosystem, proposed as a measure of the degree to which a desired ecological functional goal has been achieved post‐restoration, is determined as the rate of change of the ratio of primary production to CR. Shifts in the P/R ratio were evident in reaches post‐restoration, presumably as a result of changes in hydraulic structure, supporting the utility of the ratio by describing a direct link between instream hydraulic conditions and ecosystem function.

Organic Matter Decomposition and Ecosystem Metabolism as Tools to Assess the Functional Integrity of Streams and Rivers–A Systematic Review

“…For the remaining types of environmental changes, the effectiveness of organic matter decomposition and ecosystem metabolism as bioassessment tools varied between 50% and 82% (Figure 12). Particularly interestingly was the fact that both organic matter decomposition [207,216,217] and ecosystem metabolism [240][241][242] were effective in detecting the effects of restoration practices. Despite the low number of studies, this result suggests that these ecosystem functions may be useful indicators for the evaluation of restoration practices.…”

“…Despite the difficulties in incorporating indicators of stream functional integrity in large scale bioassessment programs, these can be particularly useful in bioassessment programs at smaller scales. Examples include the evaluation of the effects of stream restoration practices [66,207,216,[240][241][242] or of particular point source pollution (pesticide spill [253], wastewater treatment plant [110,254]).…”

Resistance and resilience of stream metabolism to high flow disturbances

“…Together, ER and GPP can elucidate whether a stream is a net producer (autotrophic; GPP > ER) or consumer (heterotrophic; ER > GPP) of carbon. Ecosystem metabolism is coupled with other ecosystem processes (e.g., nitrogen uptake; Hall and Tank, 2003) and is used to monitor stream health (Young et al, 2008;Jankowski et al, 2021), as well as ecosystem responses to disturbance and restoration (e.g., Arroita et al, 2019;Blersch et al, 2019;Palmer and Ruhi, 2019).…”

Net Ecosystem Production of a River Relying on Hydrology, Hydrodynamics and Water Quality Monitoring Stations

“…Among the complex interaction of nutrients, biomass and trophic structure, NEP can be used, for example, as a means to explain carbon fluxes [10,11], given the potential of rivers to store, mineralize and transport carbon to coastal areas [9]. To accurately estimate NEP, data associated with flow and water quality must be reliable [12]. Nonetheless, different deployed instruments are needed.…”