Table 3. Threshold point values (>0.8) for the twelve environmental variables and the three most suitable areas identified by the model in Kruger National Park for Bacillus anthracis occurrence (see Fig 1).
| Section | Pafuri | Shingwedzi | Letaba | Kruger National Park mean (range) |
|---|---|---|---|---|
| n pixels in area of interest | 1646 | 3834 | 4447 | 18921 |
| n cases in area of interest | 302 | 131 | 81 | 597 |
| n pixels containing cases | 68 | 90 | 26 | 219 |
| n pixels > = 0.8 threshold | 75 | 50 | 4 | 134 |
| Altitude (altitude) | 228.806 | 281 | 225.933 | 292 (145–570) |
| Calcium (caventer) | 171.835 | 184.626 | 198.049 | 148 (10–282) |
| Ephemeral Water Distance (ephdist) | 2069.046 | 0 | 13181.526 | 3618 (0 – 20384) |
| Seasonal Water Distance (seasdist) | 3169.587 | 0 | 7038.007 | 4124 (0–14764) |
| Permanent Water Distance (permdist) | 2190.000 | 46840.200 | 733.333 | 12461 (0–53450) |
| Geology Venter (geologyventer) | LB, CS, AL | AL | EC | LB, CS, AL, EC |
| INDVI (indvi) | 8.589 | 9.368 | 8.868 | 7.34 (-775–15) |
| Landscape (landscapegert) | 25,28 | 35 | 21,22 | 21, 22, 25, 28, 35 |
| Landtype (ltypeventer) | Pa04,Pa05 | Le05 | Le01 | Le01, Le05, Pa04, Pa05 |
| Precipitation Driest Quarter (precdryq) | 9 | 14 | 23.733 | 14.7 (8–36) |
| SOTER Soil ID (sotersoilid) | ZA21,ZA22 | ZA115 | ZA282 | ZA21, ZA22, ZA115, ZA282 |
| Temperature Seasonality (tempseasonality) | 3389.097 | 3687 | 3759.9333 | 3439 (2838–3828) |
LB–Karoo system; Olivine rich basalts, sub-ordinate alkali basalts, shoshonites [41]. CS–Karoo system; Fine grained sandstone, mudstone, chert (Cave sandstone and redbed stages) [41]. AL–Quarternary; Alluvium [41]. EC–Karoo system; Shale with coal seams, mudstone, grit (Ecca series) [41]. 15 –Colophospermum mopane forest. 21 –Combretum / Acacia nigrescens rugged veld. 22 –Combretum / Colophospermum mopane rugged veld. 25 –Adansonia digitata / Colophospermum mopane rugged veld. 28 –Limpopo / Luvuvhu floodplain. 35 –Salvadora angustifolia floodplains. ZA21, ZA115 –Eutric cambisols (A cambisol (CM) can be defined as having either a cambic or a mollic horizon. A cambic horizon is a weakly developed mineral soil horizon and a mollic horizon is a surface horizon of mineral soil that is dark in colour, relatively deep and contains (dry weight) at least 1% organic matter or 0.6% organic carbon) [28]. Le01: Letaba landtype; Le05: Shingwedzi Landtype; includes the Shingwedzi river; Pa04 and 05: Pafuri Landtype [25]. ZA22 –Eutric leptosols (A leptosol (LP) can be defined through a limit in depth by continuous hard rock within 25 cm from the soil surface, overlying material with a calcium carbonate equivalent of more than 40 percent within 25 cm from the soil surface or less than 10 percent (by weight) fine earth to a depth of 75 cm or more from the soil surface) [28]. ZA282 –Leptic phaeozems (Continuous rock starting between 50 and 100 cm from the soil surface with a mollic horizon and (1) a base saturation of 50 percent or more and no secondary carbonates, at least to a depth of 100 cm from the soil surface and (2) with no diagnostic horizons other than an albic, argic, cambic or vertic horizon) [28].