Health check The latest State of

THE STATE OF AUSTRALIA’S PLANTS

THE FEDERAL GOVERNMENT’S LATEST HEALTH CHECK ON AUSTRALIA’S ENVIRONMENT MAKES FOR UNCOMFORTABLE READING, REPORTS PROFESSOR BRETT SUMMERELL, CHIEF SCIENTIST AND DIRECTOR RESEARCH.

Every five years (or in some cases a little longer), the federal government issues a State of the Environment report, documenting how the environment and biodiversity is faring under current challenges. Is the environment degrading or is it in repair? And what factors are most problematic?

Unsurprisingly – given our current climate and biodiversity crises – the picture the report paints is generally less than encouraging, and this is particularly evident in the latest instalment, released by the Federal Minister for the Environment and Water in late July. Prior to the black summer bushfires in 2019/20 most of the country was beset by a particularly severe and prolonged drought, which primed so many of our ecosystems for intense and extensive bushfires. These fires, of course, caused immeasurable losses in our flora, fauna and fungi, and it will take many years to fully comprehend their impact. Two subsequent La Niña years (and a third to come) has certainly assisted in recovery of the bush, but also flooded large areas, causing another version of biodiversity loss.

State of the Environment reports typically focus on a variety of aspects of the environmental challenges facing Australia. A significant component of that is reporting on specific threats to biodiversity – such as land clearing, climate change and invasive species. All of these threats have contributed to the federal government almost doubling (77 to 151) the number of listed threatened plant species since 2016.

Exotic species – including invasive pests and diseases, weed species and fauna such as rabbits, goats, deer and camels – are a significant threat to plants. The latest report noted that there are now more exotic plant species than native species in the country, which in itself is not surprising nor necessarily concerning. The key issue is the number of species that become naturalised (about 10%) and then become problematic weeds (about 1% of the total number of exotic species). Botanic gardens are clearly places where exotic species occur – and where a very large component of the total number will be found. Our responsibility is to ensure that all of the species of plants we grow will not “escape” and spread across landscapes. There is no doubt that in the past this has occurred, and so now we have very strict protocols (known as Weed Risk Assessment Protocols – WRAPs) to assess new introductions of plants and reject any species that might not pass this test.

Invasive diseases like Phytophthora root rot and Myrtle Rust are very much a focus for the protection of flora in Australia and the impact was highlighted in the latest report. These diseases are pushing plant species towards extinction and so we, and our partners, have a strong focus on ensuring the collection of affected species into seed banks, into ex situ nursery collections and in the ground in the Gardens. Advances in genomic tools now allow

‘The number of species listed as threatened has almost doubled since 2016’

us to analyse these collections so that we can ensure that what we have represents as much of the evolutionary potential of a species as is possible. This means that the collection of plants or seeds in the Seed Bank or nursery contains all the genes for that species, so that if the species disappears in the wild, we have a collection that can be used to repopulate and reintroduce. This type of data is a huge advance in the management of at-risk species and, as the technology improves and becomes more affordable, we can start to do this for more and more species.

Climate change is undoubtedly the most extreme threat affecting plants now and into the future. This has, of course, been exemplified by the impacts of drought, fires and floods, but there are also insidious impacts in alpine areas where the climatic conditions for certain species of plant disappear. While climate change is a global issue that requires collaborative and concerted action, it is clear that Australia will be impacted more than many countries because of the intrinsic nature of our existing environment. We need to lead on action on climate change if we expect the rest of the world to do so, in order to protect our ecosystems and environments, and ultimately to protect us.

An important component in tackling climate change in the long term will be to restore country by planting trees and rehabilitating ecosystems. This will not necessarily be a quick fix – trees take a long time to grow and to fix carbon in order to reduce carbon dioxide levels in the atmosphere. We need to reduce emissions faster than that, so it is critical that across the country, and

Rhodamnia maideniana – a recent addition to the federal government’s list of threatened species. The specimen pictured is under attack by myrtle rust, a fungal disease whose impact is exacerbated by climate change.

across the planet, there is a halt to land clearing. This will then allow us to begin the process of healing the environment, both through reducing the emissions we put out and by repairing damaged country.

One pleasing component of the latest State of the Environment report was the significant recognition and input from Indigenous people. There is a strong acknowledgement that it is critical to involve Indigenous people in the care and rehabilitation of the environment. The report’s assertion that “Australia can benefit greatly from taking a holistic and culturally grounded approach to managing our environment and growing Indigenous ways of doing, knowing and knowledge sharing” is a great summary of a forward-looking approach based on thousands of years of accumulated knowledge.

There is of course much research now being undertaken to address the important issues affecting plants (and hence the rest of the environment) in the biodiversity crisis humanity has initiated. As the report acknowledges, there is also much we can all do as individuals – including reducing our own emissions, making informed purchasing decisions, supporting action and research, and continuing to lobby and support for action to minimise climate change. KEY FINDINGS 2021 State of the Nation report • There are now more foreign terrestrial plant species in

Australia than native species. • At least 19 Australian ecosystems have been reported as showing signs of collapse or near collapse. • Around 7.7 million hectares of habitat for terrestrial threatened species was cleared or substantially degraded between 2000 and 2017. • Australia has the third highest amount of soil organic carbon loss in the world, behind China and the US.