Vegetation dynamics in Bishrampur collieries of northern Chhattisgarh, India: eco-restoration and management perspectives

Remediation of heavy metal-contaminated iron ore tailings by applying compost and growing perennial ryegrass (Lolium perenne L.)

Improper disposal of heavy metal-contaminated iron ore tailings poses a significant risk to the surrounding environments. Adding compost and growing ryegrass could be a cost-effective long-term solution for remediation of iron ore tailings. We conducted a glasshouse study to investigate the impact of compost amendment (0, 50, 75 and 100% w/w) on growth and accumulation of heavy metals (Cu, Fe, Mn, Pb, Ni and Zn) and As in shoots of perennial ryegrass (Lolium perenne L.) grown in two iron ore tailings (Site A and Site B mines, Pilbara, Western Australia). Ryegrass was harvested 45 and 60 days after sowing. Site A iron ore tailings had total concentrations (mg kg^-1) of Fe (449,000), Mn (6900), Zn (109), Co (16) and As (7.3). Site B mine tailings had total concentrations (mg kg^-1) of Fe (457,000), Ni (21), Zn (109) and As (45). Both tailings had low cation exchange capacity, organic matter, air porosity and near-neutral pH, but varied in particle size distribution (Site A-clay loam and Site B-sandy loam). Ryegrass germination was higher in the extract of Site B than Site A tailings. Increasing compost-to-tailings ratio increased dry shoot biomass at 45 days. The heavy metal/metalloid concentrations in shoots significantly decreased with increasing compost-to-tailings ratio, except for Cu and Zn. The bioconcentration factor (BCF) of heavy metals (metal concentration in shoot/total metal concentration in substrate) significantly decreased with an increasing proportion of compost in growth substrate. The BCF was >1 for Zn and Cu, and <1 for other heavy metals. A high concentration of organic matter in compost treatments likely contributed to the enhanced mobilisation of Cu and Zn for plant uptake. In contrast, compost stabilised other metals/metalloids in the tailings to decrease their uptake by ryegrass and maintain plant growth despite relatively high Mn, Fe, As and Pb concentrations in iron ore tailings.

Structure, diversity and ecological function of shrub species in an urban setup of Sarguja, Chhattisgarh, India

The vegetation plays important role in urban environment and associated ecology. Urban vegetation experienced various changes due to biotic and natural interference which alter the vegetation structure, function and ecology. The present study deals with the assessment of shrub species structure, diversity, biomass, volume, C storage and CO₂ mitigation potential in an urban setup. Total four sites were selected, viz., east, west, north and south directions of Ambikapur City. A sum of eight shrub species representing seven families was recorded in Ambikapur City area. The highest representatives were recorded towards east direction (seven species with six families) and lowest towards south direction (five species with five families). The total density of shrubs ranged between 230 and 570 individual ha^- 1 being highest at east direction and least at south direction. The higher diversity was found at east direction. The shrub biomass was ranged between 0.999 and 2.603 t/ha being highest at north direction and lowest at east direction. The shrub volume, C storage and CO₂ mitigation values reflected similar trend as in case of shrub biomass. The shrub volume, C stock and CO₂ mitigation values were ranged from 0.141 to 0.250 m³/ha, 0.437 to1.132 t/ha and 1.597 to 4.156 t/ha, respectively, among the various sites. The species like Cestrum nocturnum and Nerium oleander are found to be potential in terms of various ecological services such as biomass, C storage and CO₂ mitigation in different sites. However, Lantana camara was also found to be potential species under urban setup which can be utilized for its various ecological functions. Further, it was found that the contribution of the non-native species was higher over native species in terms of stand density, basal area, biomass, C stock, volume and CO₂ mitigation potential among different study sites.

Herbaceous dynamics and CO2 mitigation in an urban setup-a case study from Chhattisgarh, India

Adjoining areas of urban environment has undergone rapid alteration in structure, composition and ecological changes, which makes them a dynamic entity. During the present investigation, herbaceous vegetation were studied in east, west, north and south directions of Ambikapur township at various seasons during March 2017 to April 2018. A total of 18 species representing 11 families were recorded at various directions of Ambikapur township in different seasons. Asteraceae was the predominant family in the study area. Highest species counts were recorded during summer season. Among the herbaceous vegetation, more than two-thirds of the herb species were exotic in nature, revealing the anthropogenic role towards loss of indigenous species. Highest species density was recorded in north direction (152,000 herb/ha during rainy, 104,000 herb/ha in winter and 184,000 herb/ha in summer) and lowest in south direction (90,000 herb/ha during rainy, 72,000 herb/ha in winter and 88,000 herb/ha in summer) in all seasons. Higher Shannon diversity (2.71 in rainy, 2.69 in winter and 3.07 in summer) and richness (0.67 in rainy, 0.52 in winter and 0.66 in summer after west direction) were recorded in the north direction. Total biomass, C storage and CO₂ mitigation were found to be highest towards north direction in all seasons. Argemone mexicana, Cassia tora, Ocimum tenuiflorum and Sida acuata are the most suitable species in terms of C storage, CO₂ mitigation under urban setup. Beside, some weed species also reflected significant potential. CO₂ mitigation by herb species can act as complimentary system towards climate cane adaptation beside other vegetal layers. Such studies are also very much effective towards development of greenery in an urban setup leading to climate mitigation process.