Skip to main content

Table 2 Results of the randomisation tests on six environmental variables

From: Explaining the geographic spread of emerging epidemics: a framework for comparing viral phylogenies and environmental landscape data

Environmental variable Path model Treated as a resistance or conductance factor Single-tree analysis: D value (p-value) 100 trees analysis: % of trees with p < 0.05
Croplands straight-line not applicable −0.013 (0.43) 7 %
  least-cost conductance −0.069 (0.67) 0 %
  least-cost resistance 0.014 (0.39) 28 %
  random walk conductance −0.061 (0.35) 1 %
  random walk resistance 0.012 (0.28) 27 %
Forests straight-line path not applicable 0.001 (0.42) 0 %
  least-cost path conductance −0.046 (0.84) 0 %
  least-cost path resistance 0.013 (0.49) 2 %
  random walk path conductance −0.064 (0.72) 3 %
  random walk path resistance −0.035 (0.91) 0 %
Savannas straight-line path not applicable −0.075 (0.89) 0 %
  least-cost path conductance 0.018 (0.17) 1 %
  least-cost path resistance −0.059 (0.75) 0 %
  random walk path conductance −0.003 (0.81) 4 %
  random walk path resistance −0.072 (0.96) 0 %
Elevation straight-line path not applicable 0.055 (0.02*) 52 %
  least-cost path conductance −0.072 (0.86) 0 %
  least-cost path resistance 0.078 (0.00*) 81 %
  random walk path conductance −0.061 (0.44) 0 %
  random walk path resistance 0.067 (0.10) 72 %
Human density straight-line path not applicable −0.076 (0.94) 0 %
  least-cost path conductance 0.063 (0.04) 17 %
  least-cost path resistance −0.069 (0.90) 0 %
  random walk path conductance −0.072 (0.99) 12 %
  random walk path resistance −0.070 (0.78) 0 %
Inaccessibility straight-line path not applicable 0.070 (0.00*) 18 %
  least-cost path conductance −0.047 (0.84) 0 %
  least-cost path resistance 0.089 (0.00*) 51 %
  random walk path conductance −0.060 (0.66) 0 %
  random walk path resistance 0.077 (0.18) 35 %
  1. For each combination of environmental variable and path model, the test is applied to a single phylogeny, and to a set of 100 trees. For the former, the D statistic and p-value of the test are shown. For the latter, we report the percentage of trees for which p < 0.05
  2. (*) p-value < 0.05