Oral Presentation- Symposium 12th International Mammalogical Congress

Australia’s digging mammals: foraging beneath the surface contributes to ecosystem services (#436)

Leonie E Valentine 1 , Katinka X Ruthrof 2 , Rebecca Fisher 3 , Giles Hardy 2 , Richard Hobbs 1 , Trish Fleming 2
  1. University of Western Australia, Crawley, WA, Australia
  2. School of Veterinary and Life Sciences, Murdoch University, Perth, WA, Australia
  3. Australian Institute of Marine Science, Perth, WA, Australia

The digging activities of mammals, although small at a local scale, are important for broader scale ecosystem services within landscapes. Australia has a large number of digging mammals that are identified as ecosystem engineers through their bioturbation of soil. Of these 29 species, approximately 70% are threatened, with mammals such as bandicoots, bilbies and bettongs having undergone substantial population and range declines within the last 200 years due to multiple threats. Our study examines how the southern brown bandicoot (Isoodon obesulus), a persisting marsupial in novel peri-urban environments, can alter soil nutrients and plant growth, subsequently influencing ecosystem functioning. We examined soil nutrients of foraging pits along the pit profile (in the pit, the discarded spoil heap, and undug ground) and examined seedling growth rates using soil cores collected from the same locations. The excavated spoil heap contained higher amounts of nutrients essential for plant growth (e.g. potassium). Seedlings grown in the spoil soil were the largest plants; being 1.5 times taller than seedlings grown in undug soil and double the height of seedlings grown in pit soil. The foraging actions of bandicoots alters soil nutrients, creating microhabitats that facilitate plant growth. We believe the extensive loss of Australian digging mammals is associated with a concurrent loss of ecosystem services, suggesting that the health and functioning of Australian landscapes may have drastically altered as these species declined. The reintroduction of digging mammals may therefore be essential, not only for species conservation, but also for ecosystem restoration.