Benthic macroinvertebrate pilot protocol summary report: Mid-Atlantic Network (2009–2014)

Wofford, John; Dammeyer, Nathan

The Mid-Atlantic Network (MIDN) pilot benthic macroinvertebrate monitoring protocol was implemented to assess proposed methods for the collection of long-term monitoring data on aquatic resources for the National Park Service’s (NPS) Inventory and Monitoring Program (I&M; MIDN 2015). This pilot protocol was implemented in eight of ten MIDN parks from 2009–2018. This report includes a summary of data from 2009–2014 , a critical review of the pilot protocol, and explanations for why MIDN ultimately modified pilot methods and began implementing state methods for the MIDN benthic macroinvertebrate monitoring protocol. From 2009–2014, the MIDN pilot effort resulted in the collection of 140 taxa of benthic macroinvertebrates. Taxa richness in individual parks ranged from 49 to 85. Importantly, pilot methods often resulted in the collection of samples that had too few individual macroinvertebrates to allow for the use of state-established thresholds of stream impairment. Multi-metric scores of stream ecological health using MIDN pilot methods were also highly variable over time at individual sites. In general, multi-metric scores were not trending over time. Given the high temporal variability and the lower sample sizes of individuals per sample using MIDN methods (thus precluding the utilization of state thresholds of stream impairment), MIDN pilot methods were ultimately deemed unsuitable for long-term objectives. As such, MIDN began utilizing state methods in 2015 and fully transitioned to state protocols in 2019. Broadly speaking, by switching to state protocols, MIDN began sampling a larger area to increase the representativeness and size (i.e. number of individuals) of the macroinvertebrate sample. In addition, as reflected in state protocols, MIDN began subsampling of the macroinvertebrate samples during laboratory processing. As noted above, this report includes data collected from 2009–2014. From 2015–2018, MIDN pilot methods and state methods were utilized simultaneously at a subset of sampling sites. In 2019, only state methods were utilized and MIDN pilot methods were dropped completely. Future analyses will evaluate if a direct comparison between MIDN pilot data and data collected under state protocols during the transition years from 2015–2018 (and beyond) can be made.

Benthic macroinvertebrate pilot protocol summary report: Mid-Atlantic Network (2009–2014)

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