1. Department of Natural Resources Management, Debre Markos University, Burie campus, Ethiopia
2. School of Postgraduate Studies, Universitas Diponegoro, Semarang, Indonesia
3. Department of Biology, Faculty of Science and Mathematics Universitas Diponegoro, Semarang, Indonesia
4. College of Agriculture and Environmental Science, Bahir Dar University, Bahir Dar, Ethiopia
5. Department of Statistics, Faculty of Science and Mathematics Universitas Diponegoro, Semarang, Indonesia