FIG. 4 in Feral Burros and Other Influences on Desert Tortoise Presence in the Western Sonoran Desert

FIG. 4.—Path diagram for Spearman correlations (P <0.05, j rj> 0.4) between anthropogenic variables in habitat for Agassiz̕s Desert Tortoises (Gopherus agassizii) in the Chemehuevi Valley, Sonoran Desert, California, USA. Variables were rank transformed. Vegetation association was coded as a categorical variable for variable importance and as an ordinal variable in order of increasing mean elevation (1 ¼ White Bursage [Ambrosia dumosa], 2 ¼ Rhatany [Krameria erecta, Krameria bicolor], and 3 ¼ Brittlebush [Encelia farinosa]) for rank correlation. Wash ¼ Chemehuevi Wash; river ¼ Colorado River; and road ¼ paved and dirt roads. Solid, bold dark arrows show positive relationships and bold dotted arrows display negative relationships. Variables with similar subjects (e.g., burro scat, burro trails) were grouped together with solid or dotted lines. Variables grouped with fine lines either had one or no variables with correlations of significance (P <0.05, j rj> 0.4). Individual variables with fine lines had low correlations.