| Literature DB >> 28616175 |
George Ashiagbor1, Emmanuel Danquah1.
Abstract
To avoid unnecessary waste of limited resources and to help prioritize areas for conservation efforts, this study aimed to provide information on habitat use by elephants between the wet and dry seasons in the Mole National Park (MNP) of Ghana. We compiled coordinates of 516 locations of elephants' encounters, 256 for dry season and 260 for wet season. Using nine predictor variables, we modeled the probability of elephant's distribution in MNP. We threshold the models to "suitable" and "nonsuitable" regions of habitat use using the equal training sensitivity and specificity values of 0.177 and 0.181 for the dry and wet seasons, respectively. Accuracy assessment of our models revealed a sensitivity score of 0.909 and 0.974, and a specificity of 0.579 and 0.753 for the dry and wet seasons, respectively. A TSS of 0.488 was also recorded for the dry season and 0.727 for the wet season indicating a good model agreement. Our model predicts habitat use to be confined to the southern portion of MNP due to elevation difference and a relatively steep slope that separates the northern regions of the park from the south. Regions of habitat use for the wet season were 856 km2 and reduced significantly to 547.68 km2 in the dry season. We observed significant overlap (327.24 km2) in habitat use regions between the wet and dry seasons (Schoener's D = 0.922 and Hellinger's-based I = 0.991). DEM, proximity to waterholes, and saltlicks were identified as the key variables that contributed to the prediction. We recommend construction of temporal camps in regions of habitat use that are far from the headquarters area for effective management of elephants. Also, an increase in water point's density around the headquarters areas and selected dry areas of the park will further decrease elephant's range and hence a relatively less resource use in monitoring and patrols.Entities:
Keywords: African elephant; Geographic Information Systems; MaxEnt; Mole National Park; Species Distribution Modeling; elephant distribution
Year: 2017 PMID: 28616175 PMCID: PMC5468139 DOI: 10.1002/ece3.2962
Source DB: PubMed Journal: Ecol Evol ISSN: 2045-7758 Impact factor: 2.912
Figure 1Picture of African elephant (Loxodonta Africana) in the headquarters area of Mole National Park (Picture credit: Gilchrist S. Darko, Dept. of Wildlife and range Management, KNUST)
Figure 2Map of Mole National Park (MNP)
Figure 4Suitable habitats used by elephants predominantly within lower elevation regions (121.9–192.2 m) of the park and within relatively flat terrains (Slope <4°) for both the dry and wet seasons: (a) elevation map and (b) slope map
Results showing accuracy assessment of habitat use model and areas of use by elephants for both dry and wet seasons
| Season | Area (km2) | AUC | Accuracy | Sensitivity | Specificity | k | TSS |
|---|---|---|---|---|---|---|---|
| Dry | 547.68 (11.29%) | 0.883 | 0.582 | 0.909 | 0.579 | 0.308 | 0.488 |
| Wet | 856.00 (17.64%) | 0.924 | 0.754 | 0.974 | 0.753 | 0.413 | 0.727 |
| Intersection | 327.24 (6.7%) |
Relative contributions of the environmental variables to elephants distribution in MNP for dry and wet season model
| Variable | Dry season (%) | Wet season(%) |
|---|---|---|
| DEM | 43.7 | 30.7 |
| Distance from saltlick | 29.1 | 28.6 |
| Distance from water holes | 14.7 | 18.7 |
| Distance from camp sites | 5.5 | 18.6 |
| Aspect | 0.4 | 1.4 |
| Distance from streams | 1.5 | 0.5 |
| Land cover | 1.2 | 0.8 |
| NDVI | 2 | 0.1 |
| Slope | 1.8 | 1.6 |
Figure 3Final output logistic models threshold to binary predictions of suitable habitat use regions using equal training sensitivity and specificity threshold values: (a) dry season and (b) wet season
Figure 5Proximity to water holes’ map showing suitable habitat regions completely within the 5‐km buffer zones of water holes in the park for both the dry and the wet seasons and hotspot clusters: (a) dry season and (b) wet season
| Class name | Reference totals | Classified totals | Number correct | Producers accuracy | Users accuracy |
|---|---|---|---|---|---|
| Built‐up/bare areas | 5 | 3 | 3 | 60.00% | 100.00% |
| Savannah grassland | 37 | 36 | 32 | 86.49% | 88.89% |
| Open Savannah woodlands/shrubs | 30 | 31 | 24 | 80.00% | 77.42% |
| Closed canopy woodland | 13 | 15 | 10 | 76.92% | 66.67% |
| Total | 85 | 85 | 69 |
Overall Classification Accuracy = 81.18%.
| Class name | Kappa |
|---|---|
| Built‐up/Bare areas | 1 |
| Savannah grassland | 0.803 |
| Open savannah woodlands/shrubs | 0.651 |
| Closed canopy woodland | 0.607 |
| Layer | var1 | var2 | var3 | var4 | var5 | var6 | var7 | var8 | var9 | var10 | var11 | var12 | var13 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| var2 | 0.012 | ||||||||||||
| var3 | 0.08 | 0.341 | |||||||||||
| var4 | 0.268 | 0.522 | *0.862 | ||||||||||
| var5 | 0.301 | 0.027 | 0.023 | 0.081 | |||||||||
| var6 | 0.324 | 0.002 | 0.017 | 0.073 | 0.491 | ||||||||
| var7 | 0.261 | −0.045 | 0.045 | 0.059 | 0.158 | 0.035 | |||||||
| var8 | 0.342 | 0.030 | 0.033 | 0.089 | *0.899 | 0.338 | 0.129 | ||||||
| var9 | 0.194 | 0.049 | 0.035 | 0.063 | 0.206 | 0.102 | −0.027 | 0.301 | |||||
| var10 | −0.002 | −0.060 | −0.082 | −0.078 | 0.024 | 0.202 | −0.128 | 0.027 | 0.100 | ||||
| var11 | 0.255 | −0.042 | 0.043 | 0.067 | 0.059 | 0.088 | 0.366 | 0.074 | −0.042 | −0.151 | |||
| var12 | 0.037 | 0.053 | 0.034 | 0.016 | 0.025 | 0.204 | −0.229 | 0.207 | 0.484 | 0.206 | −0.113 | ||
| var13 | 0.196 | 0.092 | 0.078 | 0.109 | 0.023 | 0.130 | −0.106 | 0.082 | 0.114 | 0.15 | −0.025 | 0.300 | |
| var14 | 0.137 | −0.058 | 0.035 | 0.027 | 0.066 | 0.022 | 0.768 | 0.036 | −0.074 | −0.068 | 0.437 | −0.224 | −0.093 |
var1, DEM; var2, Aspect; var3, Slope; var4, Terrain ruggedness index (TRI); var5, Proximity to Road; var6, Proximity to camp sites; var7, LULC; var8, Proximity to salt lick; var9, Proximity to water hole in dry season; var10, Proximity to stream in dry season; var11, NDVI in dry season; var12, Proximity to water hole in wet season; var13, Proximity to stream in wet season; var14, NDVI in wet season. *variables showing strong correlation.