Behavioural changes in an endangered grassland lizard resulting from simulated agricultural activities

• We examined behaviour change in simulated grazing sites.
• We investigated dispersal rate from plough area.
• Over grazing can increase basking time and dispersal.

Agricultural modification of landscapes profoundly affects the habitat of endemic species. Most Australian native grasslands have now been taken over for agriculture activities, which have dramatically changed these grassland ecosystems. Now only tiny fragments of the once more continuous native grasslands remain, and this has had a negative impact on species that occupy this habitat. One important question is how agricultural activities have altered the behaviours of endemic species in these fragmented habitats. One such species is the endangered lizard, Tiliqua adelaidensis, which is endemic to native grasslands in South Australia. Current population sites of this species are grazed by domestic stock. We found that simulated grazing led to lower body mass increases in the lizards, increased the time that lizards spent basking, reduced the tendency of lizards to move, or to move to a different burrow, but increased the tendency of lizards to disperse away from the patch of habitat provided. Simulated ploughing of the surrounding habitat led to a reduction in dispersal rates. These results suggest that heavy grazing would have adverse impacts on existing populations of T. adelaidensis. They confirm that lizards avoid ploughed substrate, perhaps explaining previous observations of extremely low gene flow between adjacent populations.