While some of the plant species of the ‘Sandstone Country’ along the escarpment of western Arnhem Land produce fleshy fruits and appear to rely on biotic methods of seed dispersal, little is known about the methods by which this is achieved – and few potential dispersers co-occur in the sandstone outcrop communities. For the present study, scat collections were made on outcrops in the northeastern area of Kakadu National Park with the hope of uncovering relationships between local frugivores and fruit-producers, and providing evidence for seasonal storage of mammal-dispersed seeds in scat prior to germination. The goals of the present project were to collect and identify sandstone community macropod scat, determine the identity of seeds present in the scat, and provide support for the role of browser/grazer macropods as effective seed dispersers via faecal seed storage in an otherwise disperser-poor local fauna. Scat containing seeds was identified as belonging to the Black Wallaroo (Macropus bernardus), a rare and locally-endemic macropod considered an intermediate browser/ grazer. These seeds were successfully germinated and the seedlings identified using molecular phylogenetic techniques as Gardenia fucata (Rubiaceae), an endemic rock-specialist species – thus establishing the first confirmation of effective seed dispersal by a ‘rock kangaroo’ in this region and the first identification of a seed disperser for this uncommon Gardenia species. The results provide support for the role of browser/grazer macropods as occasional effective seed dispersers of rock-specialist plant species in the northern monsoon tropics of Australia via faecal seed storage.
Northern Territory Naturalist
Martine, C.T., A.J. Boni, E.A. Capaldi, G. Lionheart and I.E. Jordon-Thaden. 2016. Evidence of rock-dwelling macropod seed dispersal in a tropical monsoon community. Northern Territory Naturalist 27: 68-77.