Calcicole–calcifuge plant strategies limit restoration potential in a regional semi‐arid flora

Abstract

Aim To examine calcicole and calcifuge plant strategies, as well as nutrient‐acquisition strategies, as drivers of the distribution of species in response to edaphic factors, and the degree to which these strategies may act as filters to species establishment in ecological restoration on heavily altered or reconstructed substrates. Location An 82,000‐ha area within a major mining province in the Mid‐West region of Western Australia, harboring vegetation communities ranging from species‐poor halophytic scrub on saline flats to dense biodiverse shrubland on the skeletal soils of ancient Banded Ironstone Formations (BIF). Methods Univariate and multivariate analyses were employed to examine how variation in soil chemistry and landscape position (undulating plains, slopes, and BIF crests and ridges) influenced patterns of floristic diversity, calcifuge plant strategies, and nutrient‐acquisition strategies in 538 plant species from 830 relevés. Results Landscape position was the strongest driver of species richness and vegetation functional composition. Soils became increasingly acidic and P‐impoverished along an increasing elevational gradient. Vegetation from different landscape positions was not compositionally dissimilar, but vegetation of BIF crests and ridges was up to twice as biodiverse as vegetation from adjacent lower‐relief areas and harbored higher proportions of calcifuge species and species with mycorrhizal associations. Main conclusions Topographic and edaphic complexity of BIF landforms in an otherwise relatively homogenous landscape has likely facilitated species accumulation over long time periods. They represent musea of regional floristic biodiversity, excluding only species that cannot establish or are inferior competitors in heavily weathered, acidic, skeletal, and nutrient‐impoverished soils. Plant strategies likely represent a major filter in establishing biodiverse, representative vegetation on postmining landforms in geologically ancient regions.

Understanding the interplay of temperature and moisture on the germination niche to improve management of threatened species impacted by mining

“…Acacia karina is restricted to the Blue Hills Range of the Yalgoo region (AOO approximately 44 km 2 ), with scattered populations occurring on BIF slopes and adjacent flat plains of Mt Karara and Mt Jackson (Byrne 2019). The BIF where both species are found are variously impacted by mining for iron ore (Merino‐Martín et al 2017; Cross & Lambers 2021). Conversely, A. assimilis , A. exocarpoides , and A. ramulosa are common and structurally dominant trees or large shrubs that are broadly distributed throughout central and southwestern WA (Meissner & Caruso 2008).…”

“…Acacia ramulosa mostly occurs on dunes and sandplains (Ward et al 2018), whereas A. assimilis occurs on granite outcrops, sandplains, and slopes of rocky hills, and A. exocarpoides inhabits a variety of rocky environments (Western Australian Herbarium 1998; Meissner & Caruso 2008). All three species can co‐occur on the rocky slopes of BIF in the Blue Hills Range and Mungada/Mt Karara area (Cross & Lambers 2021).…”

“…Plant communities on rocky outcrops are often highly biodiverse and floristically distinct from surrounding deep‐soil flora (Gibson et al 2012; Porembski & Barthlott 2012), often hosting both range‐restricted, edaphically specialized taxa and those that are widely distributed across different ecosystems (Gibson et al 2010; Cross & Lambers 2021). For example, across southern WA, BIFs are a distinctive geological feature occurring as isolated ranges within a mosaic of alluvial clay soils and sandplains (Byrne et al 2019).…”

Initiating pedogenesis of magnetite tailings using Lupinus angustifolius (narrow-leaf lupin) as an ecological engineer to promote native plant establishment

“…The suitability of tailings as a growth medium for native plants was investigated by broadcasting seeds of 40 local native species into all sub-treatments (Appendix S1). Selected species provided a representative sample of growth forms, life histories and nutrient-acquisition strategies desired in restoration based on the local native reference communities (Cross et al, 2019;Cross and Lambers, 2020). Seeds of all native species were collected during 2014 and 2015, cleaned to pure seed, and stored in a controlled-environment room prior to experimental use.…”

Miniaturised visible and near-infrared spectrometers for assessing soil health indicators in mine site rehabilitation

“…assisting the recovery of an ecosystem that has been degraded, damaged, or destroyed; Gann et al, 2019). Some of the most severe disturbances to soil result from surface mining (Cooke and Johnson, 2002;Cross et al, 2017). Rehabilitation or ecological restoration is often a regulatory requirement for mining companies to undertake during mine closure (Manero et al, 2021).…”