Fig. 8
From: Fire and land cover change in the Palouse Prairie–forest ecotone, Washington and Idaho, USA
(A) Warm season (May to September) lightning strike density (strikes km−1 yr−1) averaged from 1992 to 2015, and (B) lightning-caused fire density (fires per 100 km2 yr−1) from 1992 to 2015 for the mapped area within Idaho, Washington, Oregon, and Montana, USA. The black lines in (A) and (B) are borders of Idaho (center), Washington and Oregon are to the west, and Montana is to the east. The blue line is our study area defined as the Palouse bioregion north of the Snake and Clearwater rivers, while the light gray boundary outlines the entire Palouse bioregion as mapped by Bailey 1995. (C) Mean (black dot) and 95% confidence interval around the mean (gray bar) Lightning Ignition Efficiency (LIE) for three existing vegetation types that each occupy more than 33% of the mapped area