![]() However, morphological taxonomic identification of individual arthropods in such samples requires taxonomic expertise across multiple groups and a significant time investment ( Basset et al., 2012). Alternatively, arthropods can be used, as they directly make up a large proportion of terrestrial biodiversity and because arthropod species diversity and composition closely follow the diversity and composition of plant species ( Basset et al., 2012 Zhang et al., 2016), providing a convenient way to measure both sets of taxa.Īrthropods occur in high abundance and are easily sampled in so-called ‘bulk samples’ ( Rosenberg et al., 1986). Specifically, basal area, tree density, tree species richness and leaf area index have previously been shown to be important when assessing environmental rehabilitation status ( Ruiz-Jaen and Mitchell Aide, 2005 Gastauer et al., 2020a). However, measurements of vegetation structure such as canopy openness, tree density, vegetation cover and soil organic carbon are commonly used ( Wortley et al., 2013 Lorenz et al., 2019). In order to measure whether biodiversity and/or ecosystem functioning are indeed converging on designated reference (original-state) sites or are moving towards novel assemblages and/or sets of functions ( Hobbs et al., 2009), areas under restoration and rehabilitation thus require monitoring ( Derhé et al., 2016 McDonald et al., 2016).ĭespite the need for monitoring of these areas, no consensus has been reached about which environmental variables are the best indicators for measuring ecosystem state and change ( Gastauer et al., 2018, 2020a). ![]() In fact, many countries have a statutory requirement to restore disturbed areas to their original states ( SER, 2004) or to rehabilitate them. ![]() To minimise the negative impact of mining, and similar forms of disturbance, on biodiversity and ecosystem functioning, the mitigation hierarchy (avoidance, minimisation, rehabilitation or restoration, and offsets) sets guidelines to prioritise the actions that should be taken ( Rio Tinto, 2004 Bergès et al., 2020). Finally, our results show seasonal variation in arthropod communities and primer bias. Nevertheless, even the communities in the advanced-stage waste piles are different from the reference forests, and full restoration in these highly diverse ecosystems is not achieved, even after 6 to 7 years. Our results show that, over time, the arthropod community composition of the waste piles becomes more similar to the reference forests, but not to the reference cangas. In addition, we vegetation diversity and structure were measured to investigate relations between arthropod community and vegetation structure. We use samples from undisturbed cangas and forests as reference sites. We use DNA metabarcoding of bulk arthropod samples collected in both the dry and rainy seasons from waste-pile benches at various stages of revegetation: non-revegetated exposed soils, initial stage with one-to-three-year-old stands, intermediate stage with four-to-five-year-old stands, and advanced stage with six-to-seven-year-old stands. In this study, we investigate diversity and composition of the arthropod community along a post-mining rehabilitation and restoration gradient, taking seasonality and primer bias into account. Further, seeds of native canga and forest plant species are planted to point ecological succession towards natural ecosystems. During rehabilitation, these waste piles are hydroseeded with non-native plant species to achieve rapid revegetation. Here, native vegetation is logged and topsoil removed and deposited in waste piles along with mine waste. In the Carajás region of the Brazilian Amazon, exploration for iron ores has transformed the original ecosystem natural forest and a savanna formation with lateritic iron duricrust outcrops named canga. During this process, monitoring is important to ensure that desired trajectories are maintained. To reduce the net impacts of these activities, such as mining, disturbed areas are rehabilitated and restored. Human activities change natural landscapes, and in doing so endanger biodiversity and associated ecosystem services. 6University Museum, NTNU, Trondheim, Norway. ![]()
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