Predicting the distribution of C3 (Festuca spp.) grass species using topographic variables and binary logistic regression model

Abstract

The spatial distribution of different C3 and C4 grass species in tropical montane areas is commonly influenced by a number of factors that include site-specific topography. Hence, the distribution of these grasses across topographic gradients can vary significantly. In this study, we investigate the influence of topographic factors (elevation, slope and aspect) on the spatial distribution of Festuca grass species in a commonage area, comprising agro-biodiversity conservation land use. Integration of the topographic variables using GIS and binary logistic regression (LR) modelling showed that C3, Festuca grass species distribution can be predicted or mapped with an accuracy of 80% in the landscape under study. The study contributes to understanding the spatial distribution of C3 grass species and provides valuable information for designing and optimizing rangeland conservation in the subtropical montane landscapes.

Keywords:

• Topographic factors
• Festuca grass species
• GIS modelling
• binary logistic regression
• grassland management

Acknowledgements

We would like to sincerely thank the UKZN College of Agriculture, Engineering and Science for financially supporting this research. Appreciation is also extended to Greg Martrindale of KZN Biodiversity Stewardship Programme for availing relevant background information on the study site, Roy Tabernor, the Chairman of the Lions Bush Conservancy for granting access and assisting during field work. The authors similarly thank Leeth Singh and Fadzai Pwiti for their assistance during data collection. We thank Justine Nasejje, Elphas Okango and Mbulisi Sibanda for constructive statistical advice and discussions.