Understanding the Gauge plots
The gauge plots that accompany the indicator time series are meant to reflect the current status of that ecosystem component at the regional or national level. The numerical scores are determined as the percentile rank of the average (mean) value of that indicator over the last five years of the time series, relative to the series as a whole. The values typically represent quantitative scores, with more desirable conditions in the darker blue. Thus, some gauges are "right-handed" with the higher values being in darker blue, whereas other gauges are "left-handed" with lower values being in darker blue (indicating that lower values are preferable). In some instances (e.g. climate measures), the scores represented are unitless and are presented as two-way gauges, indicating that either high or low scores are observed, implying neither higher nor lower values are necessarily preferred.
Understanding the Time series plots
Time series plots show the changes in each indicator as a function of time, over the period 1980-present. Each plot also shows horizontal lines that indicate the median (middle) value of that indicator, as well as the 10th and 90th percentiles, each calculated for the entire period of measurement. Time series plots were only developed for datasets with at least 10 years of data. Two symbols located to the right of each plot describe how recent values of an indicator compare against the overall series. A black circle indicates whether the indicator values over the last five years are on average above the series 90th percentile (plus sign), below the 10th percentile (minus sign), or between those two values (solid circle). Beneath that an arrow reflects the trend of the indicator over the last five years; an increase or decrease greater than one standard deviation is reflected in upward or downward arrows respectively, while a change of less than one standard deviation is recorded by a left-right arrow.