Trend and Power Analysis for National Park Service Marine Data from 2006 to 2010: Pacific Island Network.

摘要

The Pacific Island Network (PACN) of the National Park Service (NPS) annually monitors indicators or Vital Signs of marine ecosystems. These indicators include benthic substrate cover for macro-algae, coral, coralline algae, turf algae, and macroinvertebrates; coral rugosity coral settlement (number observed per square meter and five-month period); and fish density (number of fish/125 m2), fish biomass (metric tons per hectare), and fish species richness (number of species/125 m2) (Brown et. al. 2011). These indicators are monitored annually at 15 fixed transects and each year at an additional 15 randomly-selected transects with the goal of status estimation and trend detection. In this report, the monitoring data are examined and status estimates are provided. Trend modeling provides estimates of baseline status, trend over the monitoring period, and components of variance that impact the power to detect trend. The power to detect three levels of trends is examined using a linear mixed model and Monte Carlo power simulation (Heard et al. 2007, Sims et al. 2006). A discussion of the power analysis results followed with recommendations on outcomes of interest for early trend detection.