Diesel oil spill in a subalpine meadow: 9 years of recovery

1982 ◽  
Vol 60 (6) ◽  
pp. 906-910 ◽  
Author(s):  
Joy Belsky

Two subalpine meadow communities near Mt. Baker, Washington, were inundated by a spill of 26 000 L of diesel oil in 1972. Studies were made of the initial impact of the oil on the vegetation and of community recovery over 9 years. Within two growing seasons following the spill, plant cover had decreased from a prespill cover of nearly 100% to 1% and all species except Phyllodoce empetriformis, Carex lenticularis, and Rhacomitrium sudeticum had died. Seedlings of Carex nigricans began to appear on bare soil after 1 year, followed by seedlings of other common subalpine species 2 to 4 years later. Nine years after the perturbation 5 to 20% of the ground was covered with vegetation and the original disturbance could no longer be discerned by a casual observer.

2019 ◽  
Vol 71 (1) ◽  
Author(s):  
Wendy J. Leonard ◽  
O. W. Van Auken

Abstract In the past, grasslands and savannas were common in many areas of south-central Texas, including the San Antonio area. With the advent of European settlers and their livestock, much of this area was converted to agriculture and rangeland. Today, most of San Antonio is developed, but some preservation has occurred. Restored grassland, mechanically cleared of Juniperus ashei (juniper, Ashe juniper) and other woody species in 2013, was examined and compared to adjacent non-cleared woodland. The woodland examined was dominated by Diospyros texana (Texas persimmon) and Juniperus ashei. Richness in the woodland canopy was 15 species. The understory below the canopy had 25 woody species. In the restored grassland area, herbaceous plant cover was 41.8%, woody plant cover 5.8%, bare soil 2.9%, and litter cover 49.5%. Species richness was 71, with 60 herbaceous and 11 woody species (percent cover of each from <0.1–7.1%). The most common species in the restored grassland in descending order were Nassella leucotricha (Texas winter grass), Calyptocarpus vialis (straggler daisy), Carex planostachys (cedar sedge), Sporobolus crypandrus (sand dropseed), D. texana, and Verbesina virginica (frost weed). Several C4 grass species were present with low cover but may increase in abundance over time. Four of the six most common restored grassland species were present below the woodland canopy and 12 woody species were present in the restored grassland as juveniles. Cost of restoration was approximately $38,500 ($7,500 supplies, $31,000 labor).


2019 ◽  
Vol 396 ◽  
pp. 109-120 ◽  
Author(s):  
Caroline Barbosa Monteiro ◽  
Phelype Haron Oleinik ◽  
Bruno Vasconcellos Lopes ◽  
Thalita Fagundes Leal ◽  
Osmar Olinto Möller Junior ◽  
...  

A modelling system was utilised to simulate the movement and behaviour of oil slicks for two types of hydrocarbons, a diesel and another residual, considering hydrodynamic variations. Susceptible areas to oil touching were found in adjacent regions of two vessel manoeuvring zones, in two types of zones, one in a marine coastal and another in an estuarine environment. The evaporation rates were calculated for an estimate of the mass losses. For the maritime zone, the oil particles reached the vicinity of the beaches in approximately 4 to 8 hours after the beginning of the spill simulations, while for the estuary in approximately 1 hour. For the scenarios with diesel oil, mass losses oscillated between 13 to 16% in the estuarine region, and between 23 and 29% in the marine coastal zones. The evaporation rates for scenarios with residual oil, between 2 and 5%, were considerably lower than for diesel (15 and 22%), especially for spills simulated in the estuarine region, where the oil particles reached the lagoon banks after 1 hour. Mass losses by evaporation were more intense in marine coastal areas than for oil spills simulated in estuarine regions, possibly due to the more intense hydrodynamic conditions and the longer time that the oil needs to reach the coast. The fluctuations of observed environmental conditions justify the need for a robust number of simulations for reducing the uncertainties related to the oceanographic and meteorological variability that affect oil spill movement.


Author(s):  
Fernando Gomes de Souza ◽  
Valdinar Ferreira Melo ◽  
Wellington Farias Araújo ◽  
Thiago Henrique de Castro Araújo

Currently in Brazil, the main form of erosion is caused by the impact of raindrops on the soil surface, triggering the process of water erosion and causing serious damage to agricultural areas. This study evaluated losses of soil, water, organic carbon and nutrients in different cultures, bare soil and savanna under natural rain. The experimental design was completely randomized with five treatments (bare soil - BS, cowpea bean - CB, Brachiaria brizantha - BB, corn - CO and natural savanna – SN) with three replications; The treatment of bare soil (BS), followed by the treatment cultivated with cowpea bean  (CB) showed higher losses of soil, water, organic carbon and nutrients; The highest losses of soil, water, organic carbon and nutrients in the treatment of bare soil (BS) occurred during the period of greatest erosivity; but for treatments CB, BB and CO, the highest losses occurred during the establishment of the crop, in view of the lower soil cover. Soils cultivated with Brachiaria brizantha - BB, corn - CO and in the Natural Savana - SN area were more efficient in reducing soil and water losses during all months evaluated. Plant cover produced by the (SN) treatment and by the (BB) and (CO) treatments acted to reduce the harmful effects of erosion, minimizing losses of nutrients and organic carbon. The soil should be well protected during periods when rainfall presents the highest values of erosivity index.


2009 ◽  
Vol 5 (4) ◽  
pp. 535-538 ◽  
Author(s):  
Shiping Wang ◽  
Xiaoxia Yang ◽  
Xingwu Lin ◽  
Yigang Hu ◽  
Caiyun Luo ◽  
...  

Recently, plant-derived methane (CH 4 ) emission has been questioned because limited evidence of the chemical mechanism has been identified to account for the process. We conducted an experiment with four treatments (i.e. winter-grazed, natural alpine meadow; naturally restored alpine meadow eight years after cultivation; oat pasture and bare soil without roots) during the growing seasons of 2007 and 2008 to examine the question of CH 4 emission by plant communities in the alpine meadow. Each treatment consumed CH 4 in closed, opaque chambers in the field, but two types of alpine meadow vegetation reduced CH 4 consumption compared with bare soil, whereas oat pasture increased consumption. This result could imply that meadow vegetation produces CH 4 . However, measurements of soil temperature and water content showed significant differences between vegetated and bare soil and appeared to explain differences in CH 4 production between treatments. Our study strongly suggests that the apparent CH 4 production by vegetation, when compared with bare soil in some previous studies, might represent differences in soil temperature and water-filled pore space and not the true vegetation sources of CH 4 .


2015 ◽  
Vol 24 (4) ◽  
pp. 518
Author(s):  
Melissa A. McMaster ◽  
Andrea Thode ◽  
Michael Kearsley

Seeding following high-severity wildfires is motivated by the goals of increasing vegetative cover and decreasing bare soil in order to minimise soil erosion and exotic plant invasions. We compared the ground cover and vegetation response of seeded versus non-seeded areas located in the Warm Fire in northern Arizona, where post-fire seeding treatments with Italian ryegrass (Lolium perenne spp. multiflorum (L.)) were conducted in 4000 ha of high-severity burned areas. Over the course of the study, we observed no significant difference between seeded and non-seeded plots in percentage of bare soil, total vegetative cover or exotic plant cover. However, there were significant differences in plant community composition as revealed by PERMANOVA and Indicator Species Analysis. Two years post-fire there were significantly fewer ponderosa pine seedlings, and the cover of annual and biennial forbs was significantly lower in plots that were seeded with Italian ryegrass. In the third year, the cover of native bunch grasses was significantly lower in seeded plots. The differences we observed may be due to differences in pre-existing vegetation composition because of the geographic separation of the plots across the landscape. Our results illustrate the ineffectiveness of post-fire seeding in achieving the goals of increasing vegetative cover and decreasing the invasion of non-native plants, and we suggest that alternative post-fire remediation should be considered in the future.


2019 ◽  
Vol 152 ◽  
pp. 104823 ◽  
Author(s):  
Zhengquan Zhou ◽  
Xiaojing Li ◽  
Linlin Chen ◽  
Baoquan Li ◽  
Chuanyuan Wang ◽  
...  

2003 ◽  
Vol 117 (2) ◽  
pp. 257 ◽  
Author(s):  
O. W. Archibold ◽  
E. A. Ripley ◽  
L. Delanoy

The microenvironmental effects of spring, summer and autumn burns were investigated for a small area of fescue prairie in Saskatchewan over two growing seasons. Maximum fire temperature in all burns exceeded 300°C at a height of 5-10 cm in the canopy. At a depth of 1 cm in the soil, temperature increased to 40°C during the summer burn, but was unaffected by burns at other seasons. Spring-burned grasses recovered to the same height as the unburned control plot by the end of the first summer. Grass height was similar in all plots by the end of the second growing season, but aboveground biomass in all burned plots was about half that of the control. Graminoid leaf area index at the end of the second growing season ranged from 0.65 in the control plot to 0.27 in the autumn burn. Surface albedos dropped to about 0.03 immediately after burning and took about 3 months to return to the pre-burn values near 0.20. By mid-June of the second year, albedos were similar in all plots. Soil temperatures at 50 cm depth in the burned plots were higher than in the control during the first summer and lower during the winter. The greatest winter snowpack (73 mm water equivalent) accumulated in the control, compared to 48, 35 and 25 mm in the spring, summer and autumn burned plots, respectively. In the first growing season the greatest demand for water occurred in the spring plot followed by the summer, control and autumn plots. In the second season water demand did not differ significantly among plots, reflecting the similarities in plant cover. The microenvironmental effects of a single burning episode in fescue prairie disappear rather quickly, so that there is little long-term impact on the vegetation.


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