Harnessing ecological and genomic approaches to restore Australian grasslands in the face of global change

A project undertaken at the Centre for Integrative Legume Research, School of Biological Sciences, Monash University, and supervised by Dr Kathryn Hodgins

Australian grasslands are unique ecosystems harbouring many endemic species. In south-eastern Australia less than 1% of native grasslands remain in dwindling remnant patches. Changes in land use, invasive species, and now climate change threaten what little remains. Ecological restoration seeks to reverse this historic tide of degradation, but the challenges are many. One major question in this field has been – which seeds should we plant and at which sites? Many plant species exhibit a “home court” advantage where individuals grown in local environments are more successful relative to foreign genotypes. This has led to the widespread practice of local seed sourcing. However, given changing climates, small local populations and limited seed supplies, is this practice still the best one? How can we best manage our seed sourcing to maximise our restoration efforts? To address this question, we propose to conduct well established, yet under utilised, provenance trials, while harnessing the power of cutting-edge genomics methods to identify the genetic signatures of local adaptation as well as key environmental and genetic predictors of establishment success in an Australian foundation grassland species. We will combine our genomic analysis with ecological modelling to assess the need for assisted gene flow and conduct simulations and decision analysis to determine the likely result of distinct provenance strategies under climate change. The intended outcome of this research is to generate an evolutionary framework and a set of novel tools to optimise seed sourcing for restoration.

We will use red grass as a test case to develop genomics methods to aid managers when making planting decisions. There has been limited development of methods to integrate genomic information with future climate predictions to provide tangible recommendations to managers who are actively sourcing seeds. Our study intends to tackle this knowledge gap. Specifically we will: 1) Assess the response of red grass populations to environmental variation at the phenotype level using common gardens and a diverse array of genotypes. 2) Conduct an ecological genomics analysis to identify local adaptation candidates and assess the adaptive genetic landscape of this species. In the process of doing this we will sequence the genome of an important Australian grassland species. 3) Predict the distribution of adaptive genetic variation under climate change scenarios. 4) Predict establishment success using genomic, phenotypic and climate information and then conduct simulations parameterised by these data to assess competing provenancing strategies under different climate change scenarios. Decision analysis will be used to make planting recommendations based on the outcome of the simulations.