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 |