Field notes
22 March 2020
Biological soil crusts
There are incredibly important communities of living organisms beneath our feet that most people are completely unaware of - the biological soil crusts.
Aboriginal and Torres Strait Islander people should be aware that this site may contain images, voices and names of people who have passed away.
One of the most important focus areas for our work at Boolcoomatta Reserve, in the arid rangelands of South Australia, is the hydrological rehabilitation of the property. Rain is rare and we have to make sure the landscape soaks up every bit that falls, rather than allowing channels and erosion gullies to form and let if run off, damaging the landscape.
Climate change modelling suggests the North East Pastoral district will have an overall reduction in winter rainfall patterns and more frequent, summer thunderstorms.
In other words, it never rains but it pours. Such rainfall patterns make managing the movement of water through the landscape even more important.
One piece of the puzzle that we've recently put in place is the Wiperaminga Hills Soil Conservation Project, the aim of which is to stop water and soil moving off the property quickly, and hold it longer so it is available for fauna and flora.
Boolcoomatta Station Reserve is on Adnyamathanha and Wiljakali Country. Cultural site clearance was an essential step before earthworks could begin, to ensure the protection of any identified sites of cultural significance.
This project was initiated by my predecessor Kurt Tschirner who met with Elders from the Adnyamathanha and Wilyakali Traditional Custodian groups in August 2021. Over three days the Elders were shown the area and the proposed soil conversation work. The Traditional Custodians provided valuable guidance and advice on cultural practice and use of the land and surrounds, which will help ensure the protection of cultural sites of significance for future generations.
In February 2022, two tasks were completed, first the construction of a ‘check bank’ and ‘lined drop structure’ at a major gully head that was worsening with every significant rain event. This involved pushing down the sheer edges of the gully head (watch below), filling in the plunge pool, and building a check bank either side to direct water onto a ‘drop structure’ which is geotextile fabric overlain with hard rock.
The next step was to construct a series of six check banks to reduce the speed of the water that had taken to using a station track as a creek channel.
This will help to return it to a natural situation where water is spread widely through the vegetation across the valley floor and reduce the likelihood of the erosion worsening further downstream.
This project was initiated by my predecessor Kurt Tschirner, and has included native vegetation and Traditional Custodian clearances. The final earth-moving stages were completed by a specialist using a D6 Bulldozer under the watchful eye of Bush Heritage’s expert soil conservation officer Janet Walton (who is Bon Bon Reserve’s part time field officer).
Special thanks to Henry and Charlotte Rischbieth of the Letcombe Trust for supporting this critical work.