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Worku EA, Evangelista PH, Atickem A, Bekele A, Bro‐Jørgensen J, Stenseth NC. Modeling habitat suitability for the lesser-known populations of endangered mountain nyala ( Tragelaphus buxtoni) in the Arsi and Ahmar Mountains, Ethiopia. Ecol Evol 2024; 14:e11235. [PMID: 38623519 PMCID: PMC11017409 DOI: 10.1002/ece3.11235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Revised: 02/10/2024] [Accepted: 03/25/2024] [Indexed: 04/17/2024] Open
Abstract
Habitat suitability models have become a valuable tool for wildlife conservation and management, and are frequently used to better understand the range and habitat requirements of rare and endangered species. In this study, we employed two habitat suitability modeling techniques, namely Boosted Regression Tree (BRT) and Maximum Entropy (Maxent) models, to identify potential suitable habitats for the endangered mountain nyala (Tragelaphus buxtoni) and environmental factors affecting its distribution in the Arsi and Ahmar Mountains of Ethiopia. Presence points, used to develop our habitat suitability models, were recorded from fecal pellet counts (n = 130) encountered along 196 randomly established transects in 2015 and 2016. Predictor variables used in our models included major landcover types, Normalized Difference Vegetation Index (NDVI), greenness and wetness tasseled cap vegetation indices, elevation, and slope. Area Under the Curve model evaluations for BRT and Maxent were 0.96 and 0.95, respectively, demonstrating high performance. Both models were then ensembled into a single binary output highlighting an area of agreement. Our results suggest that 1864 km2 (9.1%) of the 20,567 km2 study area is suitable habitat for the mountain nyala with land cover types, elevation, NDVI, and slope of the terrain being the most important variables for both models. Our results highlight the extent to which habitat loss and fragmentation have disconnected mountain nyala subpopulations. Our models demonstrate the importance of further protecting suitable habitats for mountain nyala to ensure the species' conservation.
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Affiliation(s)
- Ejigu Alemayehu Worku
- Centre for Ecological and Evolutionary Synthesis (CEES), Department of BiosciencesUniversity of OsloOsloNorway
| | - Paul H. Evangelista
- Natural Resource Ecology LaboratoryColorado State UniversityFort CollinsColoradoUSA
| | - Anagaw Atickem
- Department of Zoological SciencesAddis Ababa UniversityAddis AbabaEthiopia
| | - Afework Bekele
- Department of Zoological SciencesAddis Ababa UniversityAddis AbabaEthiopia
| | - Jakob Bro‐Jørgensen
- Mammalian Behaviour and Evolution Group, Department of Evolution, Ecology and BehaviourUniversity of LiverpoolNestonUK
| | - Nils Chr. Stenseth
- Centre for Ecological and Evolutionary Synthesis (CEES), Department of BiosciencesUniversity of OsloOsloNorway
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Ahmed AS, Chala D, Kufa CA, Atickem A, Bekele A, Svenning JC, Zinner D. Potential changes in the extent of suitable habitats for geladas (Theropithecus gelada) in the Anthropocene. BMC Ecol Evol 2023; 23:65. [PMID: 37919657 PMCID: PMC10623689 DOI: 10.1186/s12862-023-02173-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 10/25/2023] [Indexed: 11/04/2023] Open
Abstract
BACKGROUND Climate change coupled with other anthropogenic pressures may affect the extent of suitable habitat for species and thus their distributions. This is particularly true for species occupying high-altitude habitats such as the gelada (Theropithecus gelada) of the Ethiopian highlands. To explore the impact of climate change on species distributions, Species Distribution Modelling (SDM) has been extensively used. Here we model the current and future extent of sutibale habitat for geladas. Our modelling was based on 285 presence locations of geladas, covering their complete current distribution. We used different techniques to generate pseudoabsence datasets, MaxEnt model complexities, and cut-off thresholds to map the potential distribution of gelada under current and future climates (2050 and 2070). We assembled maps from these techniques to produce a final composite map. We also evaluated the change in the topographic features of gelada over the past 200 years by comparing the topography in current and historical settings. RESULTS All model runs had high performances, AUC = 0.87-0.96. Under the current climate, the suitable habitat predicted with high certainty was 90,891 km2, but it decreased remarkably under future climates, -36% by 2050 and - 52% by 2070. However, since the habitats of geladas already extend to mountaintop grasslands, no remarkable range shifts across elevation gradients were predicted under future climates. CONCLUSIONS Our findings indicated that climate change most likely results in a loss of suitable habitat for geladas, particularly south of the Rift Valley. Currently geladas are confined to higher altitudes and steep slopes compared to historical sightings, probably qualifying geladas as refugee species. The difference in topography is potentially associated with anthropogenic pressures that drove niche truncation to higher altitudes, undermining the climatic and topographic niche our models predicted. We recommend protecting the current habitats of geladas even when they are forecasted to become climatically unsuitable in the future, in particular for the population south of the Rift Valley.
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Affiliation(s)
- Ahmed Seid Ahmed
- Department of Biology, Hawassa University, P. O. Box 05, Hawassa, Ethiopia.
- Department of Zoological Sciences, Addis Ababa University, P. O. Box. 1176, Addis Ababa, Ethiopia.
| | - Desalegn Chala
- Natural History Museum, University of Oslo, P. O. Box 1172, Blindern, Oslo, NO-0318, Norway
| | - Chala Adugna Kufa
- Department of Zoological Sciences, Addis Ababa University, P. O. Box. 1176, Addis Ababa, Ethiopia
- Department of Biology, Woldia University, P. O. Box 400, Woldia, Ethiopia
| | - Anagaw Atickem
- Department of Zoological Sciences, Addis Ababa University, P. O. Box. 1176, Addis Ababa, Ethiopia
| | - Afework Bekele
- Department of Zoological Sciences, Addis Ababa University, P. O. Box. 1176, Addis Ababa, Ethiopia
| | - Jens-Christian Svenning
- Center for Ecological Dynamics in a Novel Biosphere (ECONOVO), Department of Biology, Aarhus University, Ny Munkegade 114, Aarhus C, DK-8000, Denmark
- Center for Biodiversity Dynamics in a Changing World (BIOCHANGE), Department of Biology, Aarhus University, Ny Munkegade 114, Aarhus C, DK-8000, Denmark
| | - Dietmar Zinner
- Cognitive Ecology Laboratory, German Primate Center, Leibniz Institute for Primate Research, 37077, Göttingen, Germany
- Department of Primate Cognition, Georg-August-Universität Göttingen, 37077, Göttingen, Germany
- Leibniz Science Campus Primate Cognition, 37077, Göttingen, Germany
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Tafesse B, Bekele T, Demissew S, Dullo BW, Nemomissa S, Chala D. Conservation implications of mapping the potential distribution of an Ethiopian endemic versatile medicinal plant, Echinops kebericho Mesfin. Ecol Evol 2023; 13:e10061. [PMID: 37168986 PMCID: PMC10164648 DOI: 10.1002/ece3.10061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2023] [Revised: 04/08/2023] [Accepted: 04/22/2023] [Indexed: 05/13/2023] Open
Abstract
Echinops kebericho is a narrow-range multipurpose medicinal plant confined to Ethiopia. Intense land use change and overharvesting for traditional medicine have resulted in narrow distributions of its populations. It is a threatened species with a decreasing population trend. This study aims to map its potential distribution, which is key to guide conservation efforts and sustainable use. We modeled the potential distribution of E. kebercho using the maximum entropy model (MaxEnt) employing 11 less correlated predictor variables by calibrating the model at two complexity levels and replicating each model 10 times using a cross validation technique. We projected the models into the whole of Ethiopia and produced binary presence-absence maps by classifying the average map from both complexity levels applying three threshold criteria and ensembling the resulting maps into one for the final result. We mapped suitable habitat predicted with high certainty and identified local districts where E. kebericho can be cultivated or introduced to enhance its conservation. We estimated that E.kebercho has about 137,925 km2 of suitable habitat, mainly concentrated in the western highlands of the Ethiopian mountains. Our models at both complexity levels had high average performances, AUC values of 0.925 for the complex model and 0.907 for the simpler model. The variations in performance among the 10 model replicates were not remarkable, an AUC standard deviation of 0.040 for complex and 0.046 for simple model. Although E. kebericho is locally confined, our models predicted that it has a remarkably wider potential distribution area. We recommend introducing E. kebericho to these areas to improve its conservation status and tap its multiple benefits on a sustainable basis. Locally confined threatened plants and animals likely have wider potential distributions than their actual distributions and thus similar methodology can be applied for their conservation.
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Affiliation(s)
- Bedilu Tafesse
- Department of Plant Biology and Biodiversity Management, College of Natural SciencesAddis Ababa UniversityAddis AbabaEthiopia
| | - Tamrat Bekele
- Department of Plant Biology and Biodiversity Management, College of Natural SciencesAddis Ababa UniversityAddis AbabaEthiopia
| | - Sebsebe Demissew
- Department of Plant Biology and Biodiversity Management, College of Natural SciencesAddis Ababa UniversityAddis AbabaEthiopia
| | - Bikila Warkineh Dullo
- Department of Plant Biology and Biodiversity Management, College of Natural SciencesAddis Ababa UniversityAddis AbabaEthiopia
| | - Sileshi Nemomissa
- Department of Plant Biology and Biodiversity Management, College of Natural SciencesAddis Ababa UniversityAddis AbabaEthiopia
| | - Desalegn Chala
- Natural History MuseumUniversity of OsloOsloNorway
- Center for Biodiversity Dynamics in a Changing World (BIOCHANGE), Department of BiologyAarhus UniversityAarhus CDenmark
- Section for Ecoinformatics and Biodiversity, Department of BiologyAarhus UniversityAarhus CDenmark
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