Necessary sampling replication for Acadia National Park salt marsh vegetation monitoring determined through power analysis
McKenna LW and McKenna JH. 2013. Necessary sampling replication for Acadia National Park salt marsh vegetation monitoring determined through power analysis. Woodstock, VT
Power analysis for ACAD salt marsh vegetation monitoring. Based on a power analysis study by James-Pirri et al. (2007) the NCBN salt marsh monitoring protocol advises that “a minimum of 20 replicate 1m2 plots are adequate to detect subtle changes in salt marsh vegetation community composition.” To increase sample interspersion the protocol goes on to suggest that a minimum of 35 replicate plots be sampled per marsh unit. Due to the brackish nature of the ACAD marshes and potentially greater biodiversity present in these marshes (particularly Bass Harbor Marsh and Northeast Creek) it was suggested that the power analysis study used in the NCBN protocol may not be applicable for the brackish ACAD marshes. Thus a separate power analysis was undertaken in ACAD to determine the appropriate number of replicate plots needed to achieve the desired ability to detect change in these marshes. Our analysis suggests a minimum of 35 replicate plots be sampled in Bass Harbor Marsh and 50 replicate plots in Northeast creek, preferably 50 in both if resources allow. Increasing replicate sampling above 50 would likely be of benefit in Northeast Creek but is not warranted in Bass Harbor Marsh in terms of improved detection limits and given the increased costs associated with greater sampling effort. An alternative approach to consider for Northeast Creek would be to reduce the sampling area to a more narrowly defined salt-brackish tidal marsh community type and thereby reduce some of the habitat heterogeneity created by the introduction of plots with more freshwater tending species.
- Type
- Unpublished Report
- Authors
- McKenna, Lawrence; McKenna, James
- Date of Issue
- 2013-03-06
- Units
- ACAD , NETN
- Keywords
- Bass Harbor Marsh, brackish marsh, Monitoring, Northeast Creek, power analysis, Salt Marsh, Vegetation
- Subjects
- Ecological Framework: Biological Integrity | Focal Species or Communities | Intertidal Communities , Ecological Framework: Biological Integrity | Focal Species or Communities | Wetland Communities