# Modeling habitat suitability for the lesser‐known populations of endangered mountain nyala (Tragelaphus buxtoni) in the Arsi and Ahmar Mountains, Ethiopia

## TL;DR

This study identifies suitable habitats for the endangered mountain nyala in Ethiopia using modeling techniques and highlights the impact of habitat loss.

## Contribution

The study applies BRT and Maxent models to assess habitat suitability for a lesser-known population of mountain nyala.

## Key findings

- 1864 km² of the study area is identified as suitable habitat for mountain nyala.
- Land cover, elevation, NDVI, and slope are the most important variables affecting habitat suitability.
- Habitat loss and fragmentation are shown to disconnect mountain nyala subpopulations.

## 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.

Habitat suitability models have been used to determine the potential suitable habitat and the environmental factors that affect the distribution of mountain nyala (Tragelaphus buxtoni) in the Arsi and Ahmar Mountains, Ethiopia.