Performance of Vegetation in Reclaimed Slopes Affected by Soil Erosion

Soil erosion in reclaimed mines may affect plant colonization and performance, and may compromise restoration success; however, the magnitude of this effect has seldom been quantified. We monitored the dynamics of vegetation (seed bank density, seedling emergence, plant mortality, and seed production) during a growing season (2003–2004) in three constructed slopes with differing past erosion rates. The slopes are located in the Utrillas coalfield in Spain, which experiences a Mediterranean‐continental climate. In the most eroded slope, soil water availability was lower—especially in the interrill areas—and seedling emergence rate, plant survival, and seed production were also significantly lower than on the less eroded slopes. We found that vegetation recovery is dramatically constrained when rill erosion rate is 17 t ha^?1 yr^?1 and plant cover is 30%, but this effect disappears when plant cover is higher than 60%. Soil erosion in constructed slopes appears to inhibit natural plant colonization processes by increasing runoff water loss over the long‐term. Thus, when rill erosion networks develop, human intervention would be needed to minimize the loss of water and facilitate vegetation colonization.     

Response of fringing vegetation to flooding and discharge of hypersaline water at Lake Austin,Western Australia

Patterns and dynamics of the salt marsh vegetation that surrounds many of the salt lake systems of arid/semi-arid Australia are poorly known. Lake Austin is a very large salt lake with extensive areas of fringing salt marsh; it is located in the arid Yilgarn Region of Western Australia. In this study, the changes in this vegetation over a 4-year period (1998–2002), during which both a major flooding event and addition of hypersaline groundwater from a nearby mining operation occurred, are reported. The monitoring program, based on Before-After-Control-Impact (BACI) principles, was designed to detect impacts of discharging hypersaline water into the lake; however, the flooding event, the result of above average rainfall in early 2000, complicated the results. The rains of 2000 and subsequent inundation of the vegetation immediately fringing the lake bed and major inlet channels resulted in dramatic changes to the species composition of annual and short-lived species and growth of perennial species. Flooding resulted in substantial death and damage to perennial shrubs (particularly Halosarcia fimbriata) due most likely to a combination of several weeks/months of inundation and smothering by macroalgae and Ruppia, with smaller plants and those closer to the lake bed impacted upon to a greater degree. Seed germination and recruitment of new Halosarcia plants was substantial as floodwaters receded with the majority of these seedlings surviving some 2 years after flooding despite the severe drought that followed the flood. Growth rates of seedlings differed substantially and were linked to subtle differences in micro-topography. Recruitment following flooding was also demonstrated in in vitro experiments involving inundated soil cores, provided water was relatively non-saline (conductivity <30 mS cm⁻¹). A conceptual model is proposed to explain changes in fringing vegetation in response to frequency, depth, period and salinity of flooding in relation to micro-topography. Despite the profound effect of flooding, impacts of discharge were identified, with changes in topsoil pH and salinity greater in areas closer to the discharge than those further away. Impacts on vegetation characteristics were not detected. Guest Editors: J. John & B. Timms Salt Lake Research: Biodiversity and Conservation—Selected papers from the 9th Conference of the International Society for Salt Lake Research     

Microbial community study of the iron ore concentrate of the Sishen Iron Ore Mine, South Africa

As a result of the advancing global technologies and civilisation, there has been a progressive depletion of high-grade mineral deposits. Consequently, it has become increasingly important to process lower-grade ores. Phosphorous (P) and particular potassium (K) contained in the iron ore concentrates of the Sishen Iron Ore Mine have a detrimental effect on the steel making process, whereby these alkali’s cause cracks to form in the refractory lining of blast furnaces. It is initially essential to determine which microbes are indigenously present at the Sishen Iron Ore Mine before strategising how best to employ them to industrial advantage. Therefore, the objective of this study was to determine which microorganisms are indigenous to the iron ore and soil of the Sishen Iron Ore Mine. The bacterial 16S PCR and fungal ITS PCR revealed several bacterial and fungal species present in the mine environment. The bacterial isolates were found to be closely related to Herbaspirillum species, as well as Acidithiobacillus ferrooxidans, while the fungal isolates were closely related to Aureobasidium pullulans, Phaeosphaeria nodorum, Aspergillus fumigatus, and Candida parapsilosis. Isolating A. fumigatus from the iron ore/soil of the mine may indicate that A. niger, the most common fungi used for the production of citric acid, can adapt to the stringent mine environment. This would allow the application of A. niger for the production of citric acid, which may be used for the chemical leaching of the P and K from the iron ore concentrate of the Sishen Iron Ore Mine.     

Land reclamation as a cause of fine-grained sediment depletion in backbarrier tidal flats (Southern North Sea)

Grain size distribution patterns along the East Frisian coast (German Wadden Sea) were evafuated with the aim of identifying potential effects of man-made structures (e.g. dikes) on the textural composition and sediment budget of the area. It was found that the distribution of various grain size fractions and settling velocities revealed a well-defined cross-shore energy gradient. Adjacent to the mainland dike the sediment is dominated by the 3.0–3.5 phi sand fraction (>70% by weight). In comparison to the sedimentary sequences normally observed in unobstructed backbarrier depositional environments, the sediments along the land-ward margin are in this case conspicuously depleted in grain sizes <3.5 phi, the corresponding size fractions contributing <20% by weight. This suggests that the dike interrupts the normal energy gradient, thereby inhibiting the deposition of sediments with settling velocities <0.5 cm s⁻¹. This interpretation is confirmed when comparing individual cross-shore transects. The shorter the transect between the barrier island shore and the dike, the greater the fine sediment depletion. Since many faunal assemblages are grain-size specific, it is further suggested that the backbarrier ecosystem must have undergone significant modifications as a result of the substantial reduction in mud flats since the onset of dike construction some 1000 years BP. It is predicted that in the wake of the persisting and possibly accelerating sealevel rise this process of fine sediment depletion will continue and also affect progressively coarser sediments.     

Microbial Activity in High-Sulfur Reclaimed Coal Mine Overburden Sites

The high-sulfur containing coalmine overburden (OB) dumping ground of the Tirap colliery under the northeastern coalfields in Assam, India, was reclaimed by phytoremediation techniques. Native plant species were planted with line and field methods and by amending with cow dung and unmined soil. In this study, the changes in microbial activity of the reclaimed mine OB wasteland of the Tirap colliery are examined. The enzyme activities of urease, dehydrogenase, and phosphatase were compared over time. Improvements in soil pH, bulk density, and water-holding capacity in the mine OB were found. After four years of reclamation, 1.01% of particles were soil sized (=0.255 mm grain size) with the maximum degradation in the mine OB grain sizes of ?20 mm to +12 mm and of +25 mm. A 1,000-fold increase in microbial colony forming units (CFU) in the four years at the remediated site along with an increase in total DNA were evident for the mine OB reclaimed sites. The increase of microbial CFUs in the mine OB was related to a 100- to 2,000-fold increase in enzyme activity for the reclaimed areas. From this investigation, it can be concluded that the improvement of enzyme activities and the increase in microbial populations of reclaimed mine OB will yield information pertaining to the reclamation index of mine OB.     

Economic transformation and biological welfare in colonial Burma: Regional differentiation in the evolution of average height

Did economic development result in an improvement in biological welfare in the tropics before the diffusion of modern public health techniques in the 1950s and 1960s? Between the mid-19th and early 20th century, Lower Burma experienced a rapid rise in population and became increasingly commercialized as a major rice exporter. Land reclamation on a massive scale in the Irrawaddy delta required an arduous process of jungle clearance, land drainage and preparation, and canal and bund construction, mostly in malarial swamps. Once paddy lands were created, rice was grown with rudimentary tools in malarial zones. By contrast, in most parts of Upper Burma the economy remained more subsistence-oriented, and less commercialized. In this paper, we investigate changes in physical stature by processing and analyzing data reported in two anthropometric surveys conducted in various regions of Upper and Lower Burma in 1904 and in 1938-1941. An inverted U curve is observed in the evolution of average height in Lower Burma, while stature remained fairly stable in Upper Burma until the 1930s.     

Material Reuse Modeling

The techniques of water distribution modeling, a well-developed subject, have been applied to water management in an industrial park-the Bayport chemical manufacturing complex in Houston, Texas in the United States. Linear and other mathematical programming approaches were used to evaluate water reuse opportunities for a variety of scenarios, including redesigning the industrial water use network, adding a facility to the network, limiting the total water available to the network, and varying the price of water rhe results of the modeling demonstrate that a number of economical water reuse opportunities may exist for this network of facilities. More generally, the types of mathematical models developed for water reuse may find application in reuse modeling for other materials.