Grazing control and revegetation increases bird biodiversity at farm dams

Sustaining wildlife in farming landscapes is integral to reducing species loss globally. Farm dams are ubiquitous features of agricultural landscapes around the world and have the potential to support considerable biodiversity, but are relatively understudied. Here, we examined how different farm dam management strategies affect bird biodiversity. We asked whether two management actions-enhancing farm dams through fencing and revegetation, and implementing rotational grazing around unfenced dams-increased bird species richness, occupancy, and functional diversity. We compared these two management strategies to unfenced dams in continuously grazed paddocks. We conducted 2616 point counts across 109 sites on 34 farms in the temperate woodlands of south-eastern Australia over two years. We found that enhancing farm dams significantly increased bird species richness and site occupancy, a trend largely driven by non-wetland bird responses. Rotational grazing around farm dams also increased bird species richness and site occupancy. This result, however, was less pronounced than for enhanced dams and was driven mostly by open country omnivores that are relatively common in farming landscapes. Finally, we found that enhancing farm dams led to significant increases in bird functional richness, suggesting that the additional bird species that occupy enhanced dams contribute traits that are not represented in the bird species occupying unfenced dams. Our findings provide strong evidence that enhancing or rotationally grazing around farm dams can provide important benefits for farmland birds.