Ecology is not a dirty word

In late September, we found out that our Australian Government Bushfire Recovery grant application (submitted back in May 2020) was successful. Our team have been funded until June 2021 to help protect 21 threatened plant species, many of which are endemic to the Torrington and/or Bolivia Hill districts in northern New South Wales.

The 2019-20 summer fires were devastating. Collectively, the season’s fires burned through 10.3 million hectares of land in southern and eastern Australia (this doesn’t include the impact of fires in Western Australia and Northern Territory). About 82% of the burned area in the south/east was forested ecosystems, and hundreds of threatened species were impacted across the country.

In northern NSW, Torrington State Conservation Area was impacted by fire in November 2019. This unique protected area supports a high proportion of endemic plants, many of them listed on state or commonwealth threatened species lists. After reports that the entire reserve was impacted by fire, we wanted to know how many of these species had survived and which were in most urgent need of protection to reduce extinction risk. Nearby, Bolivia Hill Nature Reserve escaped the 2019 fires, but has been impacted by uncontrolled burns in recent years.

These two reserves are both part of the New England batholith, one of the most significant areas of granite outcropping in Australia. While they are similar in geology and habitat characteristics, they have very unique plant communities, each with their own collection of endemic species.

Plant communities that are restricted to, or associated with, granite rock outcrops (like our project communities), have evolved unique interactions and adaptations to survive in these harsh environments. This is partly why these systems have such a high proportion of endemic plants. Yet there are still many unknowns about the ecology of these plants, including their pollination and seed dispersal mechanisms, their soil microbiomes, and their responses to changes in fire frequency and severity. These are some of the knowledge gaps we’re hoping to address with this project.

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We’ve only been on the ground for 2.5 months (the funding announcements were delayed, so we only found out we were successful in late September). But we’ve already found some exciting new records and established monitoring sites for many of our target species. This is great news for conservation of these threatened plant species!

On our first visit to Torrington after the fires, we were pleased to see that the burn was patchy in some areas, despite the burn maps showing the entire reserve had been affected. The characteristic landscape features (i.e. large granite rock platforms and boulder fields) enabled small unburned patches to survive in these rocky areas by slowing down or breaking up fire fronts.

On one rocky outcrop, we found a single surviving individual of one of our target species, Homoranthus lunatus, literally metres from the edge of the burned area. Within the burned area, we were also excited to discover hundreds of tiny seedlings that had emerged from the ashes.

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Overall, growth and recruitment at both reserves (post fire and drought) is excellent and it’s very promising to see these species recovering from the impacts. Longer term monitoring is needed to understand whether this recovery rate continues or will be affected by future environmental changes. More fires are a particular concern; because many species have survived last year’s fire mainly as juvenile recruits, they need enough time without more intense fires to become adults and produce another generation if they are to survive extinction.

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We’ve already discovered new populations and locations for a few species, including Homoranthus binghiensis, Monotaxis macrophylla, Kardomia odontycalyx, and Acacia pubifolia,which have significantly increased the known population size and our understanding of these species in general.

Monotaxis macrophylla is an interesting fire ephemeral that we didn’t expect to find! I was lucky to see it on our first trip to the site. It only grows for a few months after fire in a boom-bust cycle, and then may not be seen at that location for many decades or longer. The ecology of these kind of species can remain a mystery for years because they’re so difficult to locate and study. The populations of this species we found at Torrington are already declining and probably won’t exist in a few months.

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Due to the late announcement of these grants, we missed the peak flowering season for many of these species, so we will have to wait until next year to find out more about the potential pollinators that visit them.

We’re looking forward to next year, when we will explore more about what habitat characteristics and ecological interactions increase the resilience of these endemic species threatened by a future of drought and fire. We also hope we’ll discover some more exciting new records!

(The project is funded by the Australian Government’s Wildlife and Habitat Bushfire Recovery program. Our awesome project team includes: John Hunter, Rose Andrew, Lizzie Wandrag, and James Mitchell-Williams).

© Manu Saunders 2020