Fig. 3: The number of taxonomic groups monitored.

The number of taxonomic groups monitored by environmental DNA (eDNA) studies (red symbols) or forest carbon (FC) projects (green symbols) in relation to the number of genomic regions used (eDNA studies only; left plot) or the number of field methods employed (right plot). For eDNA studies, different eDNA collection substrates were considered different field methods. Field methods for FC projects and taxonomic categories are listed in Fig. 1. Six FC projects that did not specify which field methods were used are excluded from the plot (three each from PlanVivo and Gold Standard). Individual data points are shown as open circles; boxes show the median, upper, and lower quartiles; whiskers represent the range of data not considered to include outliers (i.e., within 1.5× the interquartile range).