Restore and Renew webtool guidance and resources

Genetic diversity is key to the long-term success of a restoration project. Safely maximising genetic diversity sets your project up to be more robust to future challenges, including diseases, pests and climate change. 

Based on your location and target species, the webtool suggests a genetic collection area (ideal area for seed sourcing). Material that you source from within this area aligns with natural gene flow across the landscape, allowing you to maximise genetic diversity without risking outbreeding depression.

Simply sourcing seed from across the genetic collection area will improve your plant populations’ resilience to climate change. However, if you would like to further enhance climate-readiness, you can move to the second step: using the tool to find future climate-matched areas. Sourcing seed from these areas means that plants are more likely to be adapted to the future climate conditions at your site.

Restoration is more than simply putting plants in the ground – it’s about making the best decisions you can based on the most up-to-date information.

Advances in genetics mean that we no longer have to rely on generalisations and assumptions about the best seed sourcing locations. Scientists are now able to map patterns of natural gene flow across the landscape, even in places where habitat has been fragmented and gene flow disrupted.

Shifting the focus to restoring plant populations

Ecological restoration is more than tree planting; it's about restoring plant populations. A plant population is a group of plants growing in the same place at the same time and interbreeding freely. For populations to persist, plants need to produce offspring that survive, reproduce and can adapt to change. We call this attribute ‘self-sustaining’.

To be self-sustaining, populations need genetic diversity. Unfortunately, the material used in many restoration projects has low genetic diversity because it is sourced from a small number of plants, a narrow geographic area, or natural populations that have already lost genetic diversity due to habitat loss and fragmentation.

Genetic diversity and adaptive potential: the keys to long term success

A genetically diverse restored population is more likely to be self-sustaining and able to adapt to change, because genetic diversity maximises adaptive potential and minimises inbreeding.

Genetic diversity determines adaptive potential. Adaptive potential is a population’s capacity to adjust to changing environmental conditions. The higher the genetic diversity within a population, the greater the probability that at least some individuals will possess a trait that facilitates adaptation, for example, to climate change, the presence of diseases such as phytophthora or myrtle rust and other unknown future threats.

Avoiding the negative consequences of inbreeding

Inbreeding occurs when individuals that are genetically closely related mate and produce offspring. As genetic diversity decreases, inbreeding increases. Mating among close relatives increases homozygosity, so inbreeding increases the probability that offspring will express deleterious recessive traits.

Alleles are alternative versions of a gene. At a given location in the genetic code, each individual has 2 alleles (one from each parent). In most cases, alleles are either dominant (they are expressed no matter what) or recessive (they are only expressed if not masked by a dominant allele). 

Individuals that have 2 different alleles are considered 'heterozygous' – they have 2 different DNA sequences at that location in their genome.

Individuals that have 2 identical copies of the same allele are 'homozygous'. As homozygosity increases, the chance that individuals will have 2 copies of a recessive allele at a given location increases. In the absence of a dominant allele, the deleterious recessive allele is expressed. For this reason, the increased homozygosity that results from inbreeding can lead to ‘inbreeding depression’ – a decrease in the fitness of offspring. Inbreeding depression can be expressed, for example, as populations that don’t produce seed or weak seedlings that don’t survive.

Understanding gene flow in plant populations

Gene flow is the movement of genetic material from one population to another. Gene flow influences genetic diversity through the exchange of alleles (alternate versions of DNA sequence at a given location within the genome). In plants, gene flow primarily occurs through the dispersal of pollen and seeds. For example, wind and insects can carry pollen from one plant population to another, and animals can carry seeds to new areas. Both of these avenues introduce their genetic material into different plant populations. The webtool helps you replicate and reinstate natural gene flow.

To use the webtool, select your restoration site and the species you wish to plant. Based on this information, the webtool will identify a ‘genetic collection area’ for each species: the best area for sourcing plant material based on our understanding of natural gene flow. Sourcing your plant material from multiple sites across this area will improve the adaptive potential of your restored populations in the face of future challenges, including climate change.

If you would like to further support the climate resilience of your plant populations, the tool also identifies ‘future climate match areas’ for your restoration site. Plant material that is sourced from these areas already grows in conditions similar to the projected future climate conditions at your site.

Genetic collection areas: harnessing crucial genetic relationships

Genetic collection areas are areas across which gene flow naturally occurs for a particular species, or did occur prior to habitat loss and fragmentation. In these areas, material can be safely mixed without causing outbreeding depression (a reduction in fitness of some progeny due to genetic incompatibilities between the genes from the different populations). You can safely maximise genetic diversity in restored populations by sourcing material from multiple individuals at multiple sites across the entire genetic collection area. 

The genetic collection areas shown in the Restore and Renew webtool are defined by natural gene flow inferred from actual genetic relationships. We use genetic sequencing techniques to identify heritable variations in DNA sequence that tell us about gene flow among populations.

Given the extent of habitat loss and the resulting loss of genetic diversity for many species, genetic diversity in restored populations can be maximised by sourcing material from multiple individuals at multiple sites across the entire genetic collection area.

Genetic collection areas move beyond the concept of ‘local provenance’ to incorporate genetic data and insight into current and historical genetic relationships. Unlike the concept of ‘local provenance’, which is based on generalisations, genetic collection areas are based on genetic data and insight into relationships.

Local provenance is based on generalisations aimed at capturing material adapted to local conditions and avoiding outbreeding depression. However, local conditions are rapidly changing due to climate change and habitat destruction; research has consistently found that we can’t generalise about how far is too far when it comes to safely mixing material from different geographic areas, and that low genetic diversity and inbreeding in plants is typically of far greater concern than outbreeding. 

Future climate match areas: targeting climate-ready vegetation

The Restore and Renew webtool identifies ‘future climate match’ areas. Incorporating these areas into your collection strategy will help ensure your restored plant populations adapt to a changing climate. 

Future climate match areas are locations that currently experience climatic conditions similar to the conditions that your restoration site is projected to experience in the future, based on a specific future point in time, under a particular model of climatic change. This means that seed sourced from these areas are 'climate ready' – that is, they already possess characteristics that are adapted to the future climate of your site. 

The science behind the Restore and Renew webtool was first published in 2019 (Rossetto et al. 2019). Since then, our understanding of the collection, analysis and application of genomic data has continued to grow. Below is a selection of recent publications by the Research Centre for Ecosystem Resilience relevant to the methodology behind the Restore and Renew webtool.