Feral Burros and Other Influences on Desert Tortoise Presence in the Western Sonoran Desert Author Berry, Kristin H. Author Yee, Julie L. Author Lyren, Lisa M. text Herpetologica 2020 2020-12-10 76 4 403 413 https://bioone.org/journals/herpetologica/volume-76/issue-4/Herpetologica-D-20-00023.1/Feral-Burros-and-Other-Influences-on-Desert-Tortoise-Presence-in/10.1655/Herpetologica-D-20-00023.1.full journal article 10.1655/Herpetologica-D-20-00023.1 1938-5099 7712457

TABLE 3.—Importance values and Spearman̕s rank correlations for anthropogenic, topographic, and vegetation association variables on Agassiz̕s Desert Tortoises (Gopherus agassizii) in the Chemehuevi Valley, California. The importance values are based on 4096 models of presence of tortoise sign. Rank correlations show the relationship (with P -values) between predictor variables and model-averaged probability estimates for tortoise presence. African Mustard was coded 1 for presence and 0 for absence. Details of vegetation associations are in Supplemental Data S1 and models are in Supplemental Data S2 in the Supplemental Materials available online.

	Variable	Rank
Variable	importance	correlation	P -value
Burro scat (area)	0.840	0.657	<0.001
Vegetation association	0.769	0.604	<0.001
Trash (count)	0.576	0.401	<0.001
Distance to Colorado River	0.514	0.795	<0.001
Distance to Chemehuevi Wash	0.475	0.659	<0.001
Distance to houses	0.454	0.723	<0.001
Burro trails (area)	0.337	0.435	<0.001
Distance to road	0.332	0.465	<0.001
Vehicle tracks—old (area)	0.309	0.082	0.251
Vehicle tracks—recent (area)	0.265	0.319	<0.001
African Mustard (presence/absence)	0.265	0.003	0.966
Balloons (count)	0.264	0.036	0.615