Grazing Impacts

After a previous attempt from 1993 to 2003, the monitoring of grasslands in the ACT was re-commenced in 2008, with an improved research design and and inclusion of some woodland sites, concentrating on grazing effects. The potentially critical role of natural grazing in grassland ecology has received official recognition in the ACT since the previous program, including a report in 2009 by the ACT Commissioner for Sustainability and the Environment

Estimating_Plant_Species measuring_herbage_mass

Photos above: Estimating the number of plant species in a lightly grazed natural temperate grassland that contains endangered species (left); and measuring the herbage mass (kg/ha) of pasture in an open woodland (right).

The new grasslands monitoring will be integrated with monitoring of other threatened grassland animal and plant species where possible.

Mobile grazing exclosure cages are being used to estimate the amount of vegetation removed by kangaroos and rabbits (herbivore offtake in kg/ha/month).

Grazing_exclosure_cagesGazing_activity_comparisions

Photos above: Grazing exclosure cages (left) prevent access by either kangaroos only (cage with large holes), or by both rabbits and kangaroos (cage with small holes), enabling their grazing activity to be measured by comparison (right) between uncaged and caged plots. The grass in the pink hoop on the right has been caged for several months.

The level of monitoring effort needs to be limited to what is realistically achievable, yet must also be sufficient to provide unequivocal results on which management decisions can be based (e.g. to shoot / not shoot kangaroos).

This project will complement other local research on kangaroo abundance, kangaroo home range and movements, and effects of kangaroo grazing pressure on grassland biodiversity. If you would like more information about this research, please call Access Canberra on 13 22 81.

Recent research

Since the ACT Kangaroo Management Plan (KMP) was published in 2010, eight studies on the effects of kangaroo grazing on biodiversity, based on work carried out in the ACT, have been published or submitted and are in review.