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. 2020 Dec 5;10(24):14282–14299. doi: 10.1002/ece3.7027

TABLE 2.

Predictor variables required for species habitat suitability modeling

Data category Data type and measurement units Source Moving window scale Description Anticipated effect on both species (if important)
Bioclimatic data Annual precipitations (ml) https://www.worldclim.org/bioclim Not applicable Gridded bioclimatic data for the years 1970–2000 commonly used for sdm Positive nonlinear effect. Apes may show increased probability of occurrence under increase precipitation
Landscape data Aspect (degrees) https://data.humdata.org/dataset/cameroon‐elevation‐model 100,000 ha DEM acquired for Cameroon, from which aspect and slope were extracted Intermediate effects. Species may respond negatively or positively to aspect directions
Slope (m) Not applicable Positive nonlinear effects. High and mild slopes may favor species distribution
Elevation (m) Not applicable Positive nonlinear effects. Species occurrence may be high at high elevations
Distance to water bodies (m) Normalized differential water index (NDWI) (Figure S2) 100,000 ha NDWI from which distance to water bodies at 1,000 m was calculated Positive nonlinear effects. Species might find suitable habitats in close proximity to water bodies
Dense forest (ha) Yuh et al. (2019) Forest cover data obtained from the 2014 land cover data for the study area Positive nonlinear effect. Dense forest might be most suitable for species distribution
Swampy forest (ha) Positive nonlinear effect for gorillas and negative for chimpanzees. Chimpanzees might avoid swampy forests while gorillas might find most suitable habitats within swampy forests
Human footprints data Hunting pressure (no units. depend on number of hunting points) http://apes.eva.mpg.de/ 100,000 ha Hunting points collected in the field for the period 2001–2015. They include gun shells, hunter traps, hunter camps, hunter footprints and gunshots Negative nonlinear effect. Species might find suitable habitats in areas with low hunting rates but gorillas might be tolerant
Distance to roads (m) Nzooh Dongmo, N'Goran, Ekodeck, et al. (2016) Roads extracted from map of the study area from which we measured distance to roads at 1,000 m Positive linear effect. Species occurrence might increase with increase distance to roads
Population density (number of persons per square kilometer) https://sedac.ciesin.columbia.edu/data/set/gpw‐v4‐population‐density‐rev11/data‐download World population density data for the year 2015 from which the study area population was extracted Negative linear. Species might avoid areas with high population density but gorillas might be tolerant
Deforestation (ha) Yuh et al., (2019) Land cover map for the year 2015 from which deforested areas were extracted Negative nonlinear effect. Chimpanzees might completely avoid deforested areas while gorillas might be tolerant