15Fig. 2.2 ( a ) Annual minimum temperature, ( b ) annual maximum temperature, and ( c ) annual
precipitation for site locations of Bromus in the western United States. Data were summarized for
states intersecting the ecoregional range map (Fig. 2.1 ), and downloaded from http://www.grassportal.
org (accessed 16 Feb 2015, Osborne et al. 2011 ). Species were only included if the database was
represented by site locations in states throughout the species range ( http://www.plants.usda.gov ).
Numbers of sites were as follows: B. diandrus (and B. rigidus ), n = 1241; B. madritensis , n = 226;
B. rubens , n = 1568; B. tectorum , n = 2004; B. arvensis (and B. japonicus ), n = 897; B. hordeaceus ,
n = 1188. Climate data are 30-year mean annual values from 1961 to 1991; box plots show quartiles
1, 2, and 3, and upper and lower limits. Mean climate values are shown as solid dots and outliers
as gray dots. Data sources and other database information are listed in Table 2.2
2 Exotic Annual Bromus Invasions: Comparisons Among Species and Ecoregions...