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。     

Plant Recruitment in Early Development Stages on Rehabilitated Quarries in Hong Kong

To understand vegetation development during the ecological succession of rehabilitated quarries, floristic composition and structure were evaluated at different restoration phases on three quarries in Hong Kong that were planted with exotic woody species over the course of 2–14 years. A total of 113 species, of which 82 were woody species, were recorded. Exotic species dominated the overstory, and species number, richness, and diversity increased with age. Some light‐demanding early successional species were becoming dominant in the overstory vegetation at the older phases of revegetation. These species could be potential candidates for early enrichment planting with Acacia spp. Common secondary forest species occurred naturally in the understory vegetation, and were more abundant and dominant after 10 years of ecological development. The most successful restorations were on scree slopes using leguminous Acacia spp. as nurse species.     

The ecological potential of a restored abandoned quarry ecosystem in Mt. Mufu, Nanjing, China

In order to conserve the remaining rare dolomite rocks and restore Mt. Mufu, a forest restoration program has been implemented over ten years. Emergy analysis was used to evaluate the current status of the restored ecosystem, in addition, the ecological potential of the fully developed system was predicted and analyzed. Four main emergy indices of the two systems, EYR, EIR, ELR, and ESI, were calculated and compared. In addition, a relatively new emergy index, PYR, was used to evaluate the restored forest system's ecological potential. The results revealed that the current restored forest system was still in the initial stage of ecological restoration but it has already resulted in several positive effects, such as richness of plant biodiversity and improving air condition. The value of the predicted system's PYR is as great as 201.53, demonstrating that the restored forest system has a great potential for ecological development in the future.     

Induction of biofilms on quartz surfaces as a means of reducingthe visual impact of quartz quarries

Abstract

In the present study the induction of biofilms on the open rock faces of quartz quarries is reported as a feasible method of correcting the visual impact generated by the industry. Experiments were carried out to colonize quartz samples with microorganisms isolated directly from aged quarry faces. The results demonstrated the viability of inducing colonisation on quartz, which is not the most favourable material for such treatment. Furthermore, biofilm development caused a significant change in the colour of the surface of the quartz samples to greenish- or reddish yellow, which may be quantified by a colorimeter for solids. The notable change in the colour is sufficient to attenuate the bright white aspect of the quartz faces and therefore to correct the visual impact generated.     

Early Development of Soil Microbial Communities on Rehabilitated Quarries

The ecological development of soil microbial communities was studied in terms of microbial composition and structure at different rehabilitated phases on three quarries, namely Turret Hill Quarry (TH), Lam Tei Quarry (LT), and Shek O Quarry (SO), in Hong Kong. Using individual fatty acid methylesters (FAMEs) as biomarkers, Gram^? bacteria dominated at all sites, in which cy19:0 represented more than 15% of the total extracted FAMEs in all soils tested. Redundancy analysis showed that the abundance of Gram^? bacteria and Gram⁺ bacteria correlated significantly with woody species richness, native species richness, organic C, total N, and extractable NO₃‐N. Fungi (18:1w9c and 18:2w6) and arbuscular mycorrhizal (AM) fungi (16:1w5c) decreased in abundance with increasing age in SO and LT, which were positively correlated with grass coverage, soil pH, extractable NH₄‐N, and extractable P. Our study suggested that soil aeration and C availability in soils played a dominant role driving the changes in the composition and structure of Gram^? bacteria and Gram⁺ bacteria communities. Available P was the limiting factor for regulating the fungal and AM fungal communities on our local quarries.     

Silicification of the adaxial epidermis of leaves of a panicoid grass in relation to leaf position and section and environmental conditions

Many studies relate silica content in plants with internal or external factors; however, few works analyse the effect of these factors on the silicification of different cell types. In this study, we examined the effect of leaf section and leaf position, and environmental conditions on the percentages of silicified epidermal cells of a native Pampean panicoid grass, Bothriochloa laguroides D. C. Pilger. Two different environmental situations were selected for the collection of plants: a natural wetland and a quartzite quarry, located in the southeast Buenos Aires province, Argentina. Clarification and staining methodologies were applied so as to study the distribution of silicified cells in different sections of leaves of the plants collected. Two and three-factor anovas were applied to the data. Between 13% and 19% of total cells of the adaxial epidermis of leaf blades were silicified. Typical silica short cells were the largest contributor to total silicified cells (53-98%), while the second largest contributor was bulliform cells (0-30%). Percentages of total silicified cells were higher in superior than in inferior leaves, while values from leaf sections varied. When collection sites were compared, plants growing in Los Padres pond, where the silica content in soils is higher, had the higher percentage of silicified cells. Among all types of cell, bulliform cells showed differences in the proportion of silicified cells between leaf position and section and collection site. These results show that silica availability in soils is an important factor that conditions silica accumulation and overlaps with the transpiration effect.     

Restoration of a Limestone Quarry: Effect of Soil Amendments on the Establishment of Native Mediterranean Sclerophyllous Shrubs

Limestone quarries are spread over the Mediterranean Basin and have a strong environmental impact on the landscape, causing vegetation losses and soil losses. A reclamation project was conducted in a limestone quarry, situated in Arrábida Natural Park (southwest Portugal), that is dominated by mediterranean vegetation. Revegetation was conducted using three evergreen sclerophyllous shrub species (Ceratonia siliqua, Olea europaea, and Pistacia lentiscus), and new techniques were assayed to improve plant water status and nutrient status during the first phases after plantation. A water‐holding polymer (gel), fertilizer, and mycorrhiza inoculum were applied in a factorial experiment in a randomized complete block design. The success of these techniques was evaluated during 1.5 years, through monitoring of growth and ecophysiology of plants. Plant survival was high, the lowest values (95%) being recorded in C. siliqua. There were species‐specific responses to the treatments applied. Ceratonia siliqua showed the highest growth rates and was the only species with growth stimulated by fertilizer application. However, the application of fertilizer induced changes in leaf characteristics of the other two species, increasing chlorophyll and nitrogen contents. Mycorrhiza inoculum had no effect on plant response. The addition of the water‐holding polymer induced higher midday plant water potentials in C. siliqua, O. europaea, and P. lentiscus, but in the latter two species the simultaneous addition of gel and fertilizer induced the lowest water potentials. The addition of fertilizer and gel is recommended in future revegetation programs but not the combination of both when revegetating with O. europaea and P. lentiscus. The results of this experiment indicate that the use of these mediterranean species, adapted to nutrient and water stress, can circumvent harsh conditions of the quarry.     

Plant community structure, soil properties and microbial characteristics in revegetated quarries

Quarries are an important type of degraded land in southern China requiring ecological improvement and rehabilitation. In this study, plant community structure, soil properties, and microbial biomass and community function were examined at different rehabilitated phases in three quarries, namely Turret Hill Quarry, Lam Tei Quarry and Shek O Quarry, in Hong Kong. Results show that plant species richness and the percentage of native species increased with rehabilitated ages in the three quarries. The highest coverage of woody species was found at older phases, while the lowest woody coverage occurred at younger phases. Soils were strongly to moderately acidic in reaction, and more acidic soils were found in the older than in the younger sites. Organic C as well as total N and P accumulated in soil along with secondary succession in the three quarries, which were positively correlated with woody species richness. Older phases had higher total microbial biomass C and N which were positively correlated with soil organic C, total N and extractable NO₃-N, as well as woody species coverage and native species richness as shown by the biplot of redundancy analysis. Diversity of utilized carbons suggested that metabolic abilities developed gradually with rehabilitation ages in Shek O Quarry, but Turret Hill Quarry and Lam Tei Quarry had similar patterns of carbon source utilization. Principal component analysis further revealed consistent differences in metabolic diversity. Woody coverage and native species richness were significantly correlated with carbon source utilization and functional diversity.