The germination, passage and viability of Desmanthus virgatus (L.) Willenow seed through sheep and its implication for dispersal in tropical rangelands

Vast areas of semi-arid clay soil regions of northern Australia have no commercially available or adapted sown pasture legume. Livestock in the region suffer an annual prolonged protein drought. An adapted pasture legume could enhance the productivity and sustainability of the regions pastures and livestock. Agronomic trials have found that of all legumes tested to date Desmanthus species are the best survivors in such environments. Desmanthus is a native of the Americas, is palatable, productive and has good protein content. The rangeland grazing communities of Queensland appreciate the value that an adapted pasture legume would provide and are keen to improve the productivity of both their livestock and their native and introduced grass pastures. The very extensive nature of the region however poses problems in sowing and establishing a new pasture species given a lack of a sown pasture culture and broad-acre farming equipment in the region and the potential expense of sowing such vast rangelands. Ruminant livestock are known to be capable of dispersing hard-seeded leguminous seeds through their faeces, therefore faecal seeding may be one possible mechanism of establishing Desmanthus into these landscapes. This paper explores the scarification, germination, passage and viability of Desmanthus seed through sheep. It was found that scarification significantly enhances germination to 79% and 9.1% of seed fed to sheep passes through the digestive tract within 48 hours and a proportion of which remains viable and capable of germinating. We consider faecal seeding as a means of establishing Desmanthus into suitable rangelands