Establishment of woody species across 26 years of revegetation on a Queensland coal mine

Abstract

Summary The establishment success of woody plant species at 56 revegetation sites, four to 26 years old, across the Meandu open‐cut coal mine in south‐east Queensland was assessed. The revegetation process involved returning stockpiled topsoil, deep ripping and mechanical sowing of a mix of native seeds. Blakes Wattle (Acacia blakei) and less often Black Wattle (A. leiocalyx), both primarily derived from respread topsoil seed, dominate the vegetation canopy at 59% and 20% of revegetation sites, respectively. The additional sowing of seeds of many tree and shrub species within the sites has had limited success with most failing to persist or grow well. Revegetation management, for example selective thinning of acacias (Acacia spp.) saplings within the first 5 years is recommended to release the competition pressure on the poorly performing tree species. This will also allow opportunities for other less well represented shrub and herb species to persist. This study has shown that a range of tree and shrub species, including Eucalyptus spp., are performing poorly under the current revegetation regime, suggesting adjustments to revegetation species selection and/or methodologies are needed. The natural colonization of woody native species within the sites from nearby remnant vegetation is shown to be limited to only four species, and therefore is unlikely to significantly supplement the species diversity of the revegetation.

Successional dynamics of soil fungal diversity along a restoration chronosequence post‐coal mining

“…Our results suggest that OTUs associated with arbuscular mycorrhizas played an important role in the early stages of site rehabilitation, when grass cover and seedlings of naturally regenerating Acacia species (Neldner & Ngugi ) were predominant and before the dominance of woody vegetation and tree canopy closure. The dominance then shifted to ectomycorrhizas in later stages of rehabilitation, correlating with the establishment of partner tree species on the sites.…”

“…An average of 24 species of trees and shrubs, and five species of herbs, were sown in replaced topsoil at each site at a rate of approximately 8 kg/ha at establishment (Neldner & Ngugi ). An average of 15 tree species were present at year one, but by 20 years only a maximum of six species survived.…”

“…Johnson), and blue gum ( Eucalyptus tereticornis Sm.). The most successful trees in terms of biomass and frequency ( A. blakei , A. leiocalyx , and A. disparrima ) were all primarily derived from the reinstated top soil rather than supplementary sown seed (Neldner & Ngugi ).…”

Response of soil environment factors and microbial communities to phytoremediation with Robinia pseudoacacia in an open‐cut magnesite mine

“…In many countries, in order to reduce the net loss of biodiversity and ecosystem function and improve environmental quality after the end of mining operations, the law stipulates that the environmental rehabilitation of the mining area should be as close as possible to its pre-disturbance level (Gastauer et al, 2019). In recent years, a battery of methods have been adopted to restore the service functions of destroyed ecosystems after magnesite mining, of which phytoremediation, as an environmentally friendly and cost-effective method (Ahirwal & Maiti, 2018;Kaur et al, 2019;Neldner & Ngugi, 2017), has been generally used in the reclamation for tailings (Deng, Bai, Zhou, Zhu, & Yin, 2020;Li, Chen, & Wen, 2015;Wu et al, 2018;Zhou et al, 2015). Soil quality is an important component of the ecosystems restoration, providing physical, chemical, and biological supports for plant regeneration and establishment (Zhang & Chu, 2013).…”

Clumped planting arrangements improve seed production in a revegetated eucalypt woodland

“…In order for revegetated sites to become self‐sustaining, it is not only pollination and seed set that need to occur, but also regeneration (Godefroid et al ). In the Monarto Woodlands, eucalypts have been flowering and setting fruit for at least 20 years, but recruitment is rare (Paton et al, personal observation), and a lack of recruitment has also been observed in other revegetated systems (Schneemann & McElhinny ; Nelder & Ngugi ). While manipulating planting arrangements can have positive benefits for reproductive output, it will only be worthwhile if recruitment failure in these systems is also addressed.…”