Satellite Symposium 3: Pastoral Systems

Speaker's Bio

Grazing of sheep in marginal semi-arid environments is risky because grazing appears to predispose grass plants, especially palatable species, to sudden death (Hodgkinson, 1994; 1995). These early observations were based on a preliminary analysis of perennial grass survival in a single drought and supported the concept of tactical grazing proposed by Westoby et al. (1989) as a preferred management. Later this idea was developed by suggesting the existence of critical thresholds for perennial grass survival, which when crossed, collapses grass populations (Hodgkinson, 1994). Here we examine the relationship between mortality of a palatable perennial grass, Thyridolepis mitchelliana, and a number of variables measured during a 10-year period.



Mortality Model for a Perennial Grass in Australian Semi-Arid Wooded Grasslands Grazed by Sheep