Total grazing pressure - a defining concept for extensive pastoral systems in the southern rangelands of Australia

Abstract

In Australia, particularly in the southern rangelands, large populations of native and feral herbivores (including kangaroos, goats, rabbits, pigs, donkeys and camels, depending on the location) co-exist with domestic livestock. In recent decades the concept of ‘total grazing pressure’ has been developed, and widely accepted, to denote the total forage demand of all vertebrate herbivores relative to the forage supply. This concept provides a framework within which both domestic and non-domestic species can be managed to allow commercially viable livestock production, landscape maintenance or restoration and species conservation. The concept should have relevance wherever pest animal control programs, biodiversity conservation, or commercialisation of wildlife are conducted in conjunction with extensive livestock production. The rationale for the compilation of the Special Issue is outlined.

Prolific or precarious: a review of the status of Australian sandalwood (

“…Sandalwood seed continues to be dispersed by emus (Dromaius novaehollandiae), which drop the kernels away from the parent tree (George 1984;Loneragan 1990;Fox 1997). However, ingested seeds are often destroyed during digestion and if intact, are mostly deposited on the surface of the soil where they desiccate and (Hacker et al 2019). Distribution based on records of the Western Australian Herbarium (Spooner 1999;Richmond 1983;Talbot 1983;Loneragan 1990;Kealley 1991;Casson 1992; DPAW 2016; Atlas of Living Australia 2020).…”

“…Distribution of sandalwood in WA. Significantly, due to the key threat imposed by introduced and native herbivores, almost all of the rangelands including the Sandalwood Supply Area zones, are considered as 'Land used for Pastoralism'(Hacker et al 2019). Distribution based on records of the Western Australian Herbarium(Spooner 1999;Richmond 1983;Talbot 1983;Loneragan 1990;Kealley 1991;Casson 1992; DPAW 2016; Atlas of Living Australia 2020).…”

The Perils of Being Populous: Control and Conservation of Abundant Kangaroo Species

“…The latter refers to the complexity imposed on livestock managers by a variable "unmanaged" population of one or more kangaroo species. This may manifest in the inability to meet "total grazing pressure" [83] targets at the paddock and/or property level. In simple terms, total grazing pressure is defined in the above citation as "the total forage demand of all vertebrate herbivores relative to the forage supply".…”

Prospects for ecologically and socially sustainable management of total grazing pressure in the southern rangelands of Australia

“…The southern rangelands of Australia, as defined by Hacker et al (2019), lie almost entirely within the 500 mm average annual rainfall (AAR) isohyet, and mostly within the 250 mm AAR isohyet. Extensive tracts are not used for pastoral production but where grazed the broad vegetation types comprise arid mulga woodland (dominantly Acacia aneura), central arid woodlands (A. aneura and other species), semiarid woodlands (Eucalyptus, Acacia and other species), saltbush (Atriplex spp.)…”

“…Six of seven major degradation events in these landscapes can be attributed to excessive grazing pressure both immediately before and during periods of severe drought (McKeon et al 2004). Hacker et al (2019) argued that TGP is a defining concept for extensive grazing systems in the southern rangelands, noting that, globally, Australia is the only country where large native herbivores have been advantaged by pastoral development. These native herbivores -various macropod species -together with sizeable populations of exotic species including (unmanaged) goats, rabbits, camels, donkeys and pigs, can at times exert grazing pressure equivalent to that of domestic livestock (Waters et al 2018;Atkinson et al 2019).…”