Filling a void: Analysis of early tropical soil and vegetative recovery under leguminous, post‐coal mine reforestation plantations in East Kalimantan, Indonesia

Abstract

Land degradation in Borneo, one of the world's richest biodiversity hotspots, is extensive. In East Kalimantan, 5,000,000 ha of land are zoned for surface-mined coal.Deforestation from this mining threatens biodiversity and results in soil degradation, erosion, and polluted runoff, all directly impacting human populations. Revegetation methods developed for temperate forests are commonly used globally for mine rehabilitation. However, few empirical studies of native forest restoration as part of mine rehabilitation exist from wet tropical regions. Here, a chronosequence was established to observe forest succession under leguminous plantations at the PT Singlurus Pratama coal mine in East Kalimantan, Indonesia. Soil and natural regeneration data were recorded from samples of ten 20 × 60-m plots randomly located in plantings aged 2, 7, and, 9 years postmining. Linear models (LMEMs) did not reveal greater soil pH, woody plant diversity, or soil phosphorus and nitrogen in older plantings. Rather, they showed higher soil carbon in older plantings, whereas nitrogen and pH were positively correlated with woody species diversity and abundance.Graminoids were less abundant, but ferns were more abundant in older sites in an ordination analysis. The implications are exotic tree plantations shade-out competitive understory herbaceous species (such as graminoids), opening growing space for other vegetation. However, the establishment of woody species is spatially limited possibly by differences in soil degradation among sites. Our results suggest that planting leguminous trees alone may not be sufficient to restore native forests, and future management should conserve and facilitate the establishment of tropical forest topsoil.

Nitrogen recovery in reclaimed mine soil under different amendment practices in tandem with legume and non‐legume revegetation: A review

“…In the Pratama coal mines of Indonesia, exotic N‐fixing leguminous species ( Acacia mangium and Paraserianthes falcataria) accounted for 97% of vegetation dominance suppressing non‐leguminous species ( Scleria terrestris , Paspalum conjugatum and Panicum species ) and produced a 13% increase in soil N concentration in 9 years. The findings of the study suggest that planting leguminous species alone can be sometimes insufficient to restore native reforestation which can be overcome by the application of forest topsoil (Woodbury et al, 2020). Topsoil mixed 50:50 with coal mine spoil in equal blend along with native‐plant amendments (15 g of Triodia pungens biomass ) showed an N mineralization rate of 40 mg kg −1 under Triodia wiseana monoculture, 44 mg kg −1 under T .…”

Spatiotemporal Variability of Human Disturbance Impacts on Ecosystem Services in Mining Areas

“…This is likely due to the fact that ESs rarely respond instantaneously to disturbances in specific ecological processes. The impacts of mining and restoration are sustained over time [64][65][66][67][68], and may even change the ESs at the mining area for time scales in the order of decades to centuries [69][70][71]. Some studies represent an increase in the spatiotemporal lag on the pollinator and pest control functions, but at even higher lags, the carbon sequestered by large intact forests mitigates climate change, benefiting the entire global community [72].…”

The dynamics of soil carbon in revegetated post-coal mining sites: A case study in Berau, East Kalimantan, Indonesia

“…Thus, when the living organisms in the forest are decomposed, the carbon will be accumulated in the forest soil. Since deforestation is increasing due to changes in land uses, including coal mining activities (Woodbury et al 2020), it could potentially move carbon from the biosphere into the atmosphere. It will significantly contribute to the increase in greenhouse gas emissions.…”