16 October 2013

Field work underway in Kakadu National Park is investigating how much animals move between floodplains and rivers and where they get most of their food from.

Early results from field work show that during the dry season, there is a size-based variation in foraging, meaning that larger animals are getting their food from different areas compared with smaller animals.

Waterholes are enough to sustain small fish throughout the dry season, but larger animals like crocodiles mainly feed on mammals from the surrounding savanna or larger waterbodies. Large fish such as barramundi feed on floodplains and in saltwater. This highlights how important floodplains are to maintaining healthy fish and wildlife populations.

The project team has also found that underwater plants are an important place for algae to grow, and that this algae is a vital part of the food web.

However, vertical grasses like para grass support very little algae, and therefore reduce food within the food web where they prevent other plant species from growing. Para grass is an exotic weed species, but it now covers large areas of some floodplains in Kakadu.

This research would not be possible without the help of Kakadu staff and Traditional Owners, who have been providing advice, assistance and samples of catch, including pigs, buffalo, goanna, and wallaby.

The researchers have been using these samples to better understand what the larger animals are eating. The partnership has opened doors for a much better understanding of the food webs in Kakadu.

Read more about the project here.