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Table 7 PLSR Model results for infection prevalence with Borrelia burgdorferi (s.l.) in Ixodes spp. ticks, 2014–2015. VIP scores greater than 1 (highlighted in bold) indicate significant contributions of those variables to the variation explained by each component; variable weights indicate the direction of the effect. Asterisk indicates the variable(s) contributing most significantly to the variation in the component, and the strongest predictor of infection. The second component acts on residual variation not explained by the first component

From: Lyme disease risk in southern California: abiotic and environmental drivers of Ixodes pacificus (Acari: Ixodidae) density and infection prevalence with Borrelia burgdorferi

 

Weights (VIP) comp. 1

Weights (VIP) comp. 2

Avg. max. winter temp. 2013–2014

-0.040 (0.144)

0.442 (1.594)*

Elevation (m)

-0.278 (1.001)

-0.025 (0.092)

Slope

-0.103 (0.373)

-0.186 (0.670)

Canopy cover (%)

-0.091 (0.328)

-0.239 (0.861)

Litter cover (%)

0.123 (0.443)

-0.211 (0.761)

Shrub cover (%)

0.156 (0.561)

-0.373 (1.344)

Grass cover (%)

-0.144 (0.518)

0.381 (1.375)

Bare ground cover (%)

-0.296 (1.068)

0.311 (1.120)

Stem density (No./Plot)

-0.065 (0.234)

-0.202 (0.729)

Woodrat density

-0.144 (0.518)

-0.185 (0.667)

Tick diversity (Shannon’s)

0.603 (2.174)*

0.224 (0.807)

Avg. max. winter temp. 2014–2015

0.012 (0.044)

0.401 (1.446)

Avg. max. summer temp. 2014

-0.605 (2.181)*

-0.034 (0.124)

R-squared

0.529

0.086

  1. Abbreviation: VIP variable importance in the projection