Vegetation structure and defoliation patterns in heterogeneous grasslands under two herbage allowance levels

Abstract

Understanding the relationship between vegetation attributes and defoliation patterns at multiple spatiotemporal scales is crucial for optimising grazing systems. This study assessed the structural attributes of vegetation and the effects of defoliation frequency and intensity in a campos grassland under two herbage allowance (HA) levels. Vegetation metrics such as forage mass, lamina and sheath height, green/dead ratio, and lamina/sheath ratio were measured. Data were analysed across four spatial hierarchical levels using cluster analysis to describe vegetation heterogeneity and defoliation patterns. Higher HA resulted in greater heterogeneity and more selective grazing behaviour, particularly at finer spatial scales (bite and patch level). The results suggest that maintaining vegetation heterogeneity throughout the year enhances forage selection and grazing efficiency, contributing to more sustainable grazing systems, but may change species composition to higher proportions of less-palatable species over time.