Occurring across all southern hemisphere continents except Antarctica, old, climatically buffered, infertile landscapes (OCBILs) are centres of biological richness, often in biodiversity hotspots. Among a matrix of young, often disturbed, fertile landscapes (YODFELs), OCBILs are centres of endemism and diversity in the exceptionally rich flora of the south-west Australian global biodiversity hotspot, home to Noongar peoples for ≥ 48 000 years. We analysed contemporary traditional Noongar knowledge of adjacent OCBILs (e.g. granite outcrops) and YODFELs (e.g. creekline fringes) both at a single site and in two larger areas to test whether patterns of disturbance dictated by Noongar custom align with OCBIL theory. We found that Noongar traditional knowledge reflects a regime of concentrated YODFEL rather than OCBIL disturbance—a pattern which aligns with maximal biodiversity preservation. SIMPER testing found traditional Noongar OCBIL and YODFEL activities are 64–75% dissimilar, whereas Pearson’s chi-square tests revealed camping, burning, travelling through country and hunting as primarily YODFEL rather than OCBIL activities. We found that Noongar activities usually avoid OCBIL disturbance. This combined with high floristic diversity following enduring First Peoples’ presence, suggests that traditional Noongar knowledge is valuable and necessary for south-west Australian biodiversity conservation. Similar cultural investigations in other OCBIL-dominated global biodiversity hotspots may prove profitable.

Geophytes are a considerable component of Southwest Australian flora and thus, unsurprisingly, feature heavily in the diets and culture of Noongar First Nations people of this old, climatically buffered, infertile landscape-dominated global biodiversity hotspot. Of ~650 geophyte species recorded in south-western Australia, 90 are known traditional Noongar foods. Despite the significant role of geophytes in Noongar traditional lives, there is little published knowledge of the ecological effects of harvesting geophytes. We measured and observed soil and plant outcomes of tuber harvest for two Noongar staple species of Platysace Bunge to test whether it improved soil conditions for plant growth and/or aided tuber availability, as suggested for other Australian Aboriginal root crops. Harvesting of Platysace deflexa led to increases in some soil nutrient levels and, unexpectedly, to an increase in bulk density. Platysace deflexa stem abundance was restored to the pre-harvest level within 1 year post-harvest, whereas tuber weight and volume were less than pre-harvest levels after 2 years. A post-harvest increase in the proportion of small tubers in crops suggests that harvest has a renewing and homogenizing effect on tubers. Site-based differences in post-harvest P. deflexa and Platysace trachymenioides quantity of tubers were consistent with preferential harvest of some populations by present-day Noongar families and their ancestors.

High gene flow and a population structure corresponding to human rather than geographical drivers are likely to be genetic patterns of human-dispersed plant taxa. We examined variation in geographical structure and gene flow estimates based on three non-coding regions of plastid DNA in three south-west Australian members of the Platysace genus to identify whether a human influence on dispersion of utilized taxa was detectable. Edible tubers of Platysace deflexa and Platysace trachymenioides have been harvested historically by Noongar traditional owners, whereas Platysace effusa has no known cultural significance. We found differences between utilized and non-utilized taxa, particularly when considered against the generally complex phylogeographical patterning in south-west Australian plant taxa. Platysace effusa showed a pattern of high population divergence, low gene flow and multiple refugia, consistent with a long evolutionary history, past climatic oscillations and persistence in a highly fragmented landscape. In contrast, higher gene flow estimates, less divergence between populations and common haplotypes in P. deflexa and in P. trachymenioides over the south-eastern part of its range are consistent with anthropogenic influences. This study contributes to the understanding of human influences on south-west Australian plant taxa that have been present since the late Pleistocene, but to date have received little scientific attention.

Protection of biodiversity, human assets, and cultural heritage pose significant challenges to contemporary planning of bushfire mitigation activities. Current mitigation approaches are not always appropriate, and mismanagement is a source of distress for Indigenous peoples. Increased understanding of Indigenous fire knowledge and increased Indigenous participation may provide insight into more appropriate and inclusive land management for fire mitigation. We analysed contemporary Noongar and Western fire practitioner approaches within an Indigenous fire knowledge (IFK) framework to explore knowledge and aspirations for small reserves in the Southwest Australian Floristic Region (SWAFR) global biodiversity hotspot. We recorded an extensive knowledge base, characterised by a highly nuanced approach to burning, held by the Noongar coauthors. We explore potential approaches to applying this knowledge to build collaborative fire mitigation strategies with mutually beneficial outcomes for biodiversity, cultural heritage, and human assets.

Indigenous societies' interactions with plants may result in contemporary distribution patterns that reflect these relationships, such as concentration of resource species close to occupation sites or transport routes. Seeds of the cycad, Macrozamia dyeri, are food of Nyungar First People of the southeastern Southwest Australian Floristic Region. Processing of seeds by leaching in soil or water enables detoxification and preservation of the pre-colonial staple, a Nyungar technique archaeologically dated to at least 13 000 years BP. We measured the distance of M. dyeri populations to cultural landscape features and registered heritage sites. We also compared within-population plant distribution characteristics to Nyungar occupation preferences around granite inselbergs. We found evidence of Nyungar influence on contemporary distribution of M. dyeri. Populations of M. dyeri occur close to surface water features in the west and granite outcrops in the east of Nyungar country, which corresponds closely to differential pre-colonial patterns of Nyungar occupation. M. dyeri population frequency was negatively correlated with distance to registered Nyungar sites, and 75% of all M. dyeri populations occur within 3.2 km of a registered Nyungar site. We found no correlation between habitat availability and size of granite populations, but found that Nyungar occupation preferences in relation to ground surface aspect, slope and landform type correlated with intra-population M. dyeri plant distribution, suggesting a mutualistic relationship with Nyungar people, has influenced the plant's distribution. We suggest that contemporary M. dyeri distribution is therefore useful for interpreting past location-specific Nyungar land practices to inform contemporary conservation management. Our findings demonstrate that along with edaphic, climate and other environmental factors, consideration of pre-colonial human dispersal and land practices is important for plant conservation in Australia, particularly for taxa with prolonged use by humans. Further, we suggest that analyses of long-lived Macrozamia elsewhere may be useful for interpreting past Aboriginal land practices.