Key Laboratory of Genetics and Germplasm Innovation of Tropical Special Rainforest Trees and Ornamental Plants (Hainan University), Ministry of Education, School of Tropical Agriculture and Forestry, Hainan University, Haikou 570228, PR China.
Department of Agricultural Soil Science, Ecosystems, Georg-August University of Göttingen, Göttingen, Germany; Agro-Technology Institute, Peoples Friendship University of Russia, RUDN University, Moscow, Russia; Institute of Environmental Sciences, Kazan Federal University, 420049 Kazan, Russia.
Sci Total Environ. 2024 Nov 25;953:176178. doi: 10.1016/j.scitotenv.2024.176178. Epub 2024 Sep 10.
Mining is a major threat to vegetation and soil in the tropical forests. Reforestation of degraded surface mines is critically dependent on the recovery of soil health, where the nematodes play an important role. However, the key determinants of community assembly of soil nematodes during mine-restoration remain unknown in the tropical rainforests. Here, the recovery of taxonomic diversity of nematode communities and their trophic groups during reforestation of an extremely degraded tropical open-mining area is studied. The factors that may impact their recovery, such as root traits (length, area and tissue density), soil properties (pH and soil organic matter content (SOM)), and taxonomic diversities of soil bacterial and fungal communities are investigated. Differences in these parameters were evaluated in the three soil types: (i) mined soil - the erstwhile soil that was removed during mining and stock-piled for 10 years at the foot of an extremely degraded open-mining area; (ii) reforested soil, sampled from a 10-year successful restoration, which used the mined soil for reforestation; and (iii) undisturbed soil, collected from an adjacent undisturbed/not-mined tropical rainforest. A total of 11, 34 and 29 nematode-genera were identified in mined-, undisturbed-, and reforested soils, respectively. The taxonomic diversities of the 5 nematode groups in the mined soil were 1.5-5.2 times lower than in the undisturbed soil, but were similar in the restored and undisturbed soils. Taxonomic diversities of phytophagous and predator nematodes were correlated to restored root traits; whereas of bacterivores, fungivores, and omnivores were correlated to pH, SOM, soil bacterial and fungal communities. Consequently, complete loss of roots during mining likely severely reduced the nematodes, but their recovery after reforestation led to the restoration of taxonomic diversity of nematode communities. The mix-planting fast-growing tree species may be appropriate for recovering soil health, including nematode diversity, during reforestation of open tropical mines.
采矿是热带森林植被和土壤的主要威胁。退化露天矿区的复垦严重依赖于土壤健康的恢复，而线虫在这方面起着重要作用。然而，在热带雨林中，矿地恢复过程中线虫群落组成的关键决定因素仍不清楚。在这里，研究了极度退化的热带露天矿区复垦过程中线虫群落分类多样性及其营养类群的恢复情况。调查了可能影响其恢复的因素，如根系特征（长度、面积和组织密度）、土壤特性（pH 和土壤有机质含量（SOM））以及土壤细菌和真菌群落的分类多样性。在三种土壤类型中评估了这些参数的差异：（i）采矿土壤 - 曾经在采矿过程中被移除并堆积在极度退化的露天矿区脚下 10 年的土壤；（ii）重新造林土壤，取自 10 年成功恢复的样本，使用采矿土壤进行重新造林；（iii）未受干扰的土壤，从相邻未受干扰/未开采的热带雨林中收集。在采矿、未受干扰和重新造林土壤中分别鉴定出 11、34 和 29 个线虫属。在采矿土壤中，5 个线虫类群的分类多样性比未受干扰土壤低 1.5-5.2 倍，但与恢复和未受干扰土壤相似。植食性和捕食性线虫的分类多样性与恢复后的根系特征相关；而细菌食性、真菌食性和杂食性线虫与 pH、SOM、土壤细菌和真菌群落相关。因此，采矿过程中根系完全丧失可能严重减少线虫，但重新造林后其数量的恢复导致了线虫群落分类多样性的恢复。在热带露天矿的复垦过程中，混合种植速生树种可能是恢复土壤健康（包括线虫多样性）的合适选择。
