Planting to conserve threatened nomadic pollinators in NSW.
Abstract
Plant-pollinator mutualisms are fundamental to natural and agricultural systems. In Australia, several species of native plants produce large volumes of nectar and pollen, with an unusually high proportion of plants pollinated by vertebrates. Highly mobile vertebrate pollinators (birds and bats) disperse pollen over large areas during feeding bouts, promoting out-crossing and increasing genetic variation in the plants and plant populations they visit. This genetic variation builds ecological resilience in ecosystems, increasing their capacity to withstand or adapt to pressures from anthropogenic change. Long-distance pollen flow is particularly important in highly fragmented landscapes. It may also provide a mechanism to help long-lived eucalypts withstand the challenges of climate change. The times and locations of flowering in many eucalypts are relatively unpredictable. Nectar-feeding birds and bats move nomadically over long distances to maintain continuous access to productive habitat. These nomadic animals are vulnerable to loss of relatively small habitat areas - particularly those that provide resources at key times. These habitats cannot be conserved within general conservation programs as, for example, networks of protected areas; instead, they require sensitive management, including the restoration of areas outside reserves. Several species of primarily nectar-feeding birds and bats are listed as threatened under the Threatened Species Conservation Act 1995 (NSW). A consistent set of threats, including loss, degradation and fragmentation of feeding and roosting habitat (particularly on privately owned land) affects these animals. Actions to halt and reverse decline focus on habitat protection, restoration and regeneration. A large number of habitat restoration, enhancement and regeneration projects are being planned, or are in the early stages of being realised in New South Wales, and various existing sites are being augmented. These programs provide an opportunity within existing initiatives to enhance feeding habitat and improve conservation outcomes for important mobile pollinators. Not only would actions to target nomadic pollinators help conserve pollinator networks; they would also build resilience in plantings, embed them in ecological processes that are played out over large spatial scales, and amplify the benefits of local conservation efforts. Beneficial conservation outcomes for both nomadic pollinators and vegetation communities could accrue through the planting of trees that provide food during winter and early spring. This approach would increase feeding habitat during seasonal bottlenecks and establish potential food resources for a large number of species, including critically endangered regent honeyeaters, endangered swift parrots and other threatened and protected honeyeaters, lorikeets, flying-foxes and arboreal marsupials. Key winter and spring food plants for nomadic pollinators are identified in this report, as are the vegetation communities that contain them. Recommendations for plantings in key regional areas are made, and the threatened pollinators that may benefit from the plantings are identified.