采石场废弃地的生态重建研究进展

采石场的开采严重破坏了植被和土壤,形成了大量的裸露岩石斜坡,造成宏观景观支离破碎和极端的环境条件,限制了植物的生长。由于自然恢复所需时间长久,人工恢复被广泛应用于采石场废弃地的生态重建。自然演替过程是采石场生态重建的理论基础,自然演替理论可以为人工恢复措施提供指导。植物群落演替的早期阶段,非生物因素起主要作用,随着演替的推移,生物因素的重要性增强。邻近自然植被的土壤和繁殖体通过外力的扩散,对恢复起重要作用。除了非生物和其他的限制,先到达恢复地的物种竞争能力的变化能决定了演替过程。演替过程中的干扰因素往往成为演替重要的驱动力。裸露岩石斜坡的物理稳定性对植被恢复有重要影响,有机废物的使用和施肥可以影响恢复演替的方向和生物多样性。播种一定的植物能够改变恢复演替方向,加速演替过程。乡土物种适应了当地气候,能够促进演替。随着修复时间的延长,土壤有机质含量,植被覆盖度和物种丰富度不断增加,土壤微生物生物量随之增加。开展不同地区采石场植物种类的选育、研究乡土物种的功能特性、土壤微生物群落和酶的变化、植被演替过程的定位研究、植物种间的竞争关系、自然演替和人工恢复的比较研究、探索经济高效的采石场生态重建方法是未来的研究方向。

Advances in ecology restoration of abandoned quarries

Many quarries are exploited to provide construction material due to rapid progress of urbanization and industrialization. Exploitation of quarries causes lots of bare rock slopes, resulting in complete removal of vegetation and propagules, soil depletion, and landscape fragmentation. The soil erosion causes an impoverishment of nutritional and hydric status, hindering natural germination and establishment of young plants. As a result, the reutilization of abandoned quarries becomes quite difficult. The destruction of vegetation is the major factor that leads to the ecosystem degradation. Revegetation of abandoned quarries is the key to improving the ecological environment. Low water and nutrient availabilities are the primary factors limiting plant development at quarries. The establishment of a plant community is often quite low and limits the success of revegetation. Natural restoration is a very slow process, which may take hundreds of years. As a result, artificial revegetation methods have been widely used in ecology restoration of abandoned quarries. Soil management, slope stabilization, species selection, seed collection, seeding and planting strategies and techniques are recommended practices. Treatments with fertilizer may promise procedures to improve plant performance in the site with low water and nutrient availabilities. Artificial restoration of abandoned quarries should be based on spontaneous succession, which could guide artificial practices. At the early stages of vegetation succession, abiotic factors play a key role, and biotic factors become more important as the succession proceeds. Soil accumulation on the rocky slope face is a key factor for vegetation establishment at the early successional stages, but it is very difficult to retain soil on a rocky slope surface due to high rates of water erosion resulting from rainfall influence. In addition, extreme low and high temperatures and drought are the most limiting factors on these sites for plant establishment. Whether there are soil and propagulum being spread through external forces from neighboring natural vegetation will decide the success at starting stage of the succession. Besides the abiotic factors and other constraints, the arrival of some species before other species determines the course of succession through shifts in competitive abilities. Disturbances often become the important driving force of succession process. Physical stability of bare rock slopes could affect the vegetation restoration significantly, and addition of organic waste and fertilization may change or determine the direction of biodiversity of restoration succession. Sowing or planting certain plants could potentially modify the restoration successional direction, and speed up restoration succession. Native species, which has adapted to the local climate, can promote restoration succession. Organic matter, vegetation coverage, species richness and soil microbial biomass increase with increasing restoration age. Future research should focus on the studies of selection and breeding of species which applied in the abandoned quarries restoration in different regions, functional characteristics of native species, dynamics of soil microbial community and soil enzyme, positioning studies of vegetation succession process, interspecific competition among restoration vegetation, comparison of spontaneous succession and artificial restoration, exploring cost-effective methods of abandoned quarries restoration, and so on.