Barbara Allan’s short talk will be the annual review of the previous year’s Bird Blitz, a brief look at the findings across the ten years of blitzes thus far, and an invitation to participate in Blitz 11, on 24–25 October. Please come along ready to nominate your preferred sites!
The main presentation will be by Brett Howland, a Ph D student at the Fenner School at the ANU, entitled “Managing kangaroo grazing for the conservation of grassland and grassy woodland fauna including birds”.
Large mammalian grazers are ecosystem engineers, altering the resources available to species through selective consumption of plant matter, redistribution of nutrients and trampling. In south-eastern Australia, high intensity grazing by the native eastern grey kangaroo, Macropus giganteus, has been linked to ecological decline of multiple taxa. While efforts to manage the impact of grazers on biota have been undertaken, the effectiveness of these interventions is limited by a lack of knowledge of what constitutes optimal grazing levels. Brett investigated the relationship between kangaroos, grass structure and fauna to address this knowledge gap. He found that: 1) there was a strong negative relationship between the abundance of kangaroos and grass structure; 2) high intensity grazing had a negative effect on the reptile community; 3) the occurrence of a threatened grassland reptile, the striped legless lizard, Delma impar, was positively related to fine-scale grass complexity, and negatively related to kangaroo density at the landscape-scale; 4) birds with similar traits favoured similar grass structures, while bird with different traits showed a range of grass structural preferences; and 5) kangaroos selected forage habitat away from roads, where there was a higher percentage cover of short grasses.
Brett was awarded a grant from the Canberra Bird Conservation Fund for the kangaroos and birds aspects of his thesis, but members should find the interaction with other fauna fascinating as well.