Short Biography:

Dr Valerie Hagger is an ecologist based at The University of Queensland, Australia. Her research informs coastal wetland conservation and restoration through fieldwork, community engagement, large-scale data synthesis, modelling, and spatial analysis. Her novel study on the drivers of global mangrove losses and gains revealed promising conservation strategies to reverse mangrove losses in complex social-ecological systems. As a UN Ocean Decade Action, her AXA-UNESCO research fellowship explored community- and Indigenous-based management of mangrove forests to enhance their conservation and restoration. She leads research projects on (a) biodiversity assessment methods to quantify biodiversity gain with coastal wetland restoration, (b) prioritisation approaches for coastal wetland restoration that considers local knowledge, biophysical suitability, blue carbon feasibility, and benefits beyond carbon, and (c) biodiversity enhancements from wetland recovery through feral animal management. She co-authored international Best practice guidelines on mangrove restoration. She is a board member of the Society of Ecological Restoration Australasia and the Pacific representative of the international Society for Ecological Restoration.

Session Title: Coastal Comeback: Biodiversity gains with coastal wetland restoration

The world’s coastal ecosystems have suffered significant biodiversity declines from human impacts, which are being exacerbated by climate change. Restoration of coastal wetlands that enhances biodiversity and ecosystem services is urgently needed to address global biodiversity loss and climate change. A promising strategy is community or Indigenous-based management to achieve conservation outcomes.

We identified opportunities for restoration of coastal wetlands that have been lost or degraded across Australia, however we revealed several challenges with implementation. (1) Most of the land identified was in private hands, with limited areas having Indigenous land rights, thus novel opportunities for Indigenous people to lead restoration projects are needed. (2) The presence of threatened species in hydrologically modified wetlands reduced the amount of land available for restoration, therefore, mitigation of potential impacts on threatened species is necessary. However, the restoration of remaining areas can provide rich biodiversity benefits. (3) While carbon markets can incentivise restoration of coastal wetlands, high carbon prices are needed to make restoration profitable on productive agricultural land or urban land.

Verified biodiversity benefits alongside carbon credits to attain higher carbon prices or generate separate biodiversity certificates under emerging nature markets are both potential solutions. Characterising biodiversity gains with coastal wetland restoration is a challenging problem because of differences in vegetation structure and species composition along environmental gradients and it is unclear which species and metrics are indicators of biodiversity in coastal ecosystems that have low plant diversity.

We developed and combined multiple indicators of condition and biodiversity, specific to mangrove, saltmarsh, and supratidal wetland ecosystems, to assess biodiversity gains with restoration across landscapes. Key considerations for global biodiversity standards for coastal wetland restoration include (1) modelling of restored vegetation types considering current conditions, tidal inundation, and future sea-level rise, (2) using predicted vegetation types to inform selection of reference benchmarks, and (3) incorporating metrics of plant species composition and functional diversity of key fauna taxa, such as birds, bats, and benthic macroinvertebrates, to detect biodiversity changes with ecosystem transitions (rather than species diversity).