Vegetation Health Monitoring across riparian and Mulga communities
This month, the Spectrum botany and spatial ecology teams joined forces for a nine-day, multi-disciplinary survey through the remote gorges, creeks, and rugged hills of the Pilbara. The trip focused on Vegetation Health Monitoring across riparian and Mulga communities, with the survey designed to assess the leaf water potential (LWP) of key plant species. Measurements were taken both post-dawn and pre-dawn to determine levels of water stress — and yes, that meant plenty of night botany adventures under the stars 🦇😎
The monitoring program targeted both Groundwater Dependent Vegetation and Potential Groundwater Dependent Vegetation, including iconic Pilbara species such as Eucalyptus victrix, Eucalyptus camaldulensis, and Melaleuca argentea. Mulga communities (Acacia aneura complex) were also a focus, in particular the distinctive banded Mulga which is sensitive to sheet flow processes.
To measure plant water stress, leaves were sampled using a Scholander chamber. This method involves applying compressed nitrogen to an excised leaf until xylem sap appears at the cut stem. The pressure required for the sap to emerge is then recorded, providing insight into the plant’s water status.
The fieldwork came with its fair share of challenges. Severe — and spectacular — lightning storms swept through the region, flooding many access tracks and sites. Despite the difficult conditions, the team pushed on across some of the Pilbara’s most remote landscapes, including the Fortescue Marsh.
As the largest ephemeral wetland in the Pilbara, the Fortescue Marsh is listed as a Priority Ecological Community (Priority 1). Its samphire communities provide important habitat for the Threatened Night Parrot, as well as several Priority Flora species. To safely and efficiently access many of these remote sites, the team relied on helicopter support during daylight hours — weather and storm conditions permitting.
In total, the team completed 90 sites and sampled 452 trees. Despite the flooded creeklines, storm delays, and a few battle scars along the way, it was an unforgettable week of fieldwork shared with an incredible group of people.