New evidence of seed dispersal identified in Australian mammals

Date: 18, Jun, 2021
Author(s):   Palmer, B.J., Beca, G., Erickson, T.E., Hobbs, R.J., Valentine, L.E.
Publisher: Wildlife Research

Context: Mammal–seed interactions are important for structuring vegetation communities across a diverse range of ecosystems worldwide. In Australia, mammals are typically considered to be seed predators and to play insignificant roles in seed dispersal. However, very few studies have investigated endozoochorous seed dispersal in Australian species. The translocation of Australian mammals for the purposes of ecosystem restoration is increasing. Digging mammals (i.e. species that dig to obtain food or create shelter) are commonly the focus of these translocations because they are considered to be ecosystem engineers, but an understanding of their role in seed dispersal is lacking.

Aims: The aim of the present study was to expand the understanding of endozoochory in Australian digging mammals by determining whether seeds consumed by select species remain viable and able to germinate.

Methods: Scat samples were collected from five digging mammal species, known to consume seeds or fruit, across nine sites in Western and South Australia. The samples were searched for seeds, with the recovered seeds identified and tested for viability and germination capacity.

Key results: The abundance of intact seeds in scats was generally low, but 70% of the retrieved seeds appeared viable. Five species of seed germinated under laboratory conditions. These seeds were retrieved from bilby (Macrotis lagotis), boodie (Bettongia lesueur), golden bandicoot (Isoodon auratus) and quenda (I. fusciventer) scats.

Conclusions: Seeds consumed by Australian digging mammals can remain viable and germinate, indicating that digging mammals play a more important role in seed dispersal than previously considered.

Implications: Digging mammals have the potential to contribute to ecosystem restoration efforts through the dispersal of viable seeds, but there is also a risk that non-native species could be dispersed. These costs and benefits should be considered by practitioners when planning reintroductions of digging mammals.