Ownership property size,landscape structure,and spatial relationships in the Edwards Plateau of Texas (USA): landscape scale habitat management implications

The present research focused on using spatial analysis to determine relationships among land ownership property sizes and landscape structure, with a focus on conservation management implications. Indices and metrics of ownership property sizes and landscape structure were calculated for 20 km buffer areas around 31 North American Breeding Bird Survey transects, 12 located within the Edwards Plateau ecoregion and 18 in contiguous ecoregions. The number of bird species observed at each transect provided a measure of avian species richness associated with land cover classes for each respective transect (González in Urban influence on diversity of avifauna in the Edwards Plateau of Texas: effect of property sizes on rural landscape structure, Texas A&M University, 2005). Spatial correlations were calculated between each pair of the landscape indices. Spatial analysis identified a “threshold of habitat fragmentation” for the 500 acre (ac) ownership property size. Significant spatial correlations among variables showed that property sizes lower than 500 ac produced habitat fragmentation represented by a decrease in mean patch size (MN) and proximity among habitat patches (Index PROX). Spatial analysis also made possible the prioritization of ecological sub-regions of the Edwards Plateau for conservation or restoration. The Live Oak-Mesquite Savannah showed the highest average ownership property size (7305 ac) and the highest values of patch richness. Based on the results, management in the Live Oak-Mesquite Savannah sub-region should focus on the conservation of land mosaic diversity to assure native avian species turnover (Whittaker 1972). In Balcones Canyon Lands, 64 % of land was covered by farms smaller than 500 ac and the overall average ownership property size was above the threshold of fragmentation (1440 ac), implying that management policies there should focus both on habitat conservation and on restoration. In contrast, 71 % of land in the Lampasas Cut Plains was covered by farms smaller than 500 ac, and average ownership property size was very close to the fragmentation threshold (625 ac). Consequently, the results indicate that management in the Lampasas Cut Plains sub-region should focus on habitat restoration (e.g., corridors that connect isolated habitat patches). In general, the threshold of ownership property size, 500 ac, is important for conservation planning because below that threshold of property size, habitat patch size begins to decrease and the distance between equivalent patches of habitat increases. Isolated patches act as islands within a sea of less suitable habitat which produce negative effects on biodiversity. Identifying the spatial characteristics indicative of habitat fragmentation, or the likelihood thereof, is an important issue for conservation planning in places with urban sprawl influence.     

Comparison of vegetation conditions along two backcountry trails in Mount Robson Provincial Park, British Columbia (Canada)

Vegetation conditions, i.e., plant cover, species richness, and the presence of exotic species, are compared along a high-use trail (Berg Lake Trail--BLT) and a low use trail (Mt. Fitzwilliam Trail--FWT) in Canada's Mt. Robson Provincial Park. We established 71 paired quadrats (1 m x 1 m), and assessed the amount of vegetation cover and species richness by four main lifeforms, i.e., woody species, herbaceous species, ferns, and moss, lichen and fungi. The following hypotheses were tested: (1) differences exist between control and trailside quadrats in vegetation cover, species richness and floristic diversity, and (2) differences exist between the high and low-use trails in the above-mentioned three parameters. Results show that for the majority of variables the differences between the control and trailside quadrats are statistically not significant. Variables showing significant differences are relative vegetation cover (for BLT only), exposed soil (BLT and FWT), herbaceous cover (FWT), moss, lichen and fungi cover (BLT), overall species richness (BLT), and herbaceous species richness (BLT). Ruderal and exotic species are present but only on trailside quadrats of the high-use trail. Results indicate that the Park administration's strategy to disperse use in the Mt. Robson Provincial Park should be examined critically, and some guidelines for acceptability of changes should be developed.     

Degradation of N-nitrosodimethylamine (NDMA) in landscape soils

N-nitrosodimethylamine (NDMA), a potential carcinogen, was commonly found in treated wastewater as a by-product of chlorination. As treated water is increasingly used for landscape irrigation, there is an imperative need to understand the leaching risk for NDMA in landscape soils. In this study, adsorption and incubation experiments were conducted using landscape soils planted with turfgrass, ground cover, and trees. Adsorption of NDMA was negligibly weak (K(d) < 1) in all soils, indicating that NDMA has a high potential for moving with percolating water in these soils. Degradation of NDMA occurred at different rates among these soils. At 21 degrees C, the half-life (t(1/2)) of NDMA was 4.1 d for the ground cover soil, 5.6 d for the turfgrass soil, and 22.5 d for the tree soil. The persistence was substantially prolonged after autoclaving or when incubated at 10 degrees C. The rate of degradation was not significantly affected by the initial NDMA concentration or addition of organic and inorganic nutrient sources. The relative persistence was inversely correlated with soil organic matter content, soil microbial biomass, and soil dehydrogenase activity, suggesting the importance of microorganisms in NDMA degradation in these soils. These results suggest that the behavior of NDMA depends closely on the vegetation cover in a landscape system, and prolonged persistence and increased leaching may be expected in soils with sparse vegetation due to low organic matter content and limited microbial activity.     

A method to create simplified versions of existing habitat suitability index (HSI) models

The habitat evaluation procedures (HEP), developed by the US Fish and Wildlife Service, are widely used in the United States to determine the impacts of major construction projects on fish and wildlife habitats. HEP relies heavily on habitat suitability index (HSI) models that use measurements of important habitat characteristics to rate habitat quality for a species on a scale of 0 (unsuitable) to 1.0 (optimal). This report describes a method to simplify existing HSI models to reduce the time and expense involved in sampling habitat variables. Simplified models for three species produced HSI values within 0.2 of those predicted by the original models 90% of the time. Simplified models are particularly useful for rapid habitat inventories and evaluations, wildlife management, and impact assessments in extensive areas or with limited time and personnel.     

Chromatographic partitioning of impurities (H2S) contained in a CO2 stream injected into a deep saline aquifer: Part 2. Effects of flow conditions

Laboratory experiments reported in a companion paper were carried out to examine the chromatographic partitioning of impurities contained in a stream of CO₂ injected into a deep saline aquifer. The solubility of the impurity gas in the CO₂ stream compared to that of CO₂, the in situ conditions of pressure, temperature and water salinity, and the concentration of the impurity gas affect the partitioning of the two gases. For CO₂ streams containing H₂S, numerical simulations reported here have successfully replicated the laboratory results including the breakthrough of CO₂ ahead of H₂S. Sensitivity analysis performed with the numerical model has shown that flow conditions, controlled by such parameters as medium permeability, pressure gradient, dispersion, gas mobility and flow direction, affect the breakthrough time and separation of the two gases, leading to delayed or earlier breakthrough, and increasing or decreasing the time lag between the breakthrough of the two gases. Vertical bottom-up flow leads to earlier breakthrough, while top-down flow leads to delayed breakthrough. These results are important in establishing monitoring strategies at CO₂ storage sites and in evaluating the risks associated with the possible leakage of injected CO₂ that contains impurities.     

Vetiver (Vetiveria zizanioides) responses to fertilization and salinity under irrigation conditions

Vetiver (Vetiveria zizanioides) has not been widely introduced in arid and semi-arid regions where irrigation, fertilization, and salinity are important factors in plant growth. The main objective of this study was to determine the response of vetiver to fertilization (fertigation) and salinity and their interactions under irrigated conditions. The experiment was conducted in a greenhouse in 10-L pots. Combined effects of three nutrients concentrations and three salinity levels of electrical conductivity (EC) 1, 3 and 6 dS/m in the irrigation water on growth and transpiration of vetiver plants and the content of different elements in their foliage were studied. Similar contents of 3.7 g/kg Na, 5.77 g/kg Ca and 2.55 g/kg Mg were found in the foliage of all the plants irrigated with the different fertilizer and salinity levels. Concentrations of 59 mg/L N and 36.1 mg/L K in the irrigation water were sufficient for vetiver plants needs at the different salinity levels tested. The salinity threshold (the maximum EC in the soil solution that does not cause a significant yield reduction) for vetiver was between 3 and 6 dS/m. A concentration of 15.2 mg/L P in the irrigation water was the optimum value for vetiver growth in the three salinity levels, resulting in an average content of 5.95 g/kg P in plant foliage. It is suggested that vetiver is sensitive to excess P (>8.66 g/kg). Increasing EC in the irrigation water to 6 dS/m decreased plant foliage biomass mainly due to an increase in the osmotic potential of the irrigation water and high Cl⁻ concentration in the foliage.     

Temporal distribution of Ephemeroptera, Plecoptera and Trichoptera (EPT) adults at a tropical forest stream: response to seasonal variations

Temporal changes in Ephemeroptera, Plecoptera and Trichoptera (EPT) abundance were investigated monthly from January to December 2008 at a tropical forest stream of Tupah River (TR) at Gunung Jerai Forest Reserve, Malaysia. A total of 1,689 adult individuals belong to 16 families of EPT were collected from TR. EPT populations peaked in May, June and December. Mean EPT abundance was significantly different among months (Kruskal–Wallis test, P < 0.05). Among the three orders, Trichoptera had the most diverse community with eight families reported, followed by Ephemeroptera (six families) and Plecoptera (two families). The family Baetidae was the most abundant ephemeropteran. Meanwhile, caddisfly families Hydropsychidae, Leptoceridae and Lepidostomatidae were abundant at TR. However, plecopterans were mainly represented by Perlidae. There was significant difference in abundance (t = 4.863, P < 0.05) and diversity (t = 7.857, P < 0.05) of EPT adults between dry and wet seasons. Interestingly, abundance of EPT adults was higher in the dry season compared to the wet season. Consequently, seasonality impact on abundance of EPT adults at TR was obvious. The adult population of Trichoptera was dominant during the dry season. However, adults of Ephemeroptera were abundant during the wet season.     

大型中心传动浓缩（刮泥）机的应用与发展

阐述了大型中心传动浓缩机与周边传动浓缩机的结构特点及国内外的应用现状,分析了周边传动浓缩机存在的结构性缺陷,介绍了中心传动浓缩机的分类、技术特点以及其在国内的推广应用前景。     

Measuring landscape integrity (LI): development of a hybrid methodology for planning applications

Landscape integrity data-sets represent a measure of a landscape's naturalness, or its inverse, the level of human modification. Generally referred to as human footprint modeling, a hybrid approach was developed here by incorporating distance, density, and spatially explicit fuzzy logic methods for quantifying the impacts of anthropocentric infrastructure on the landscape. Integrity scores varied markedly across this large and heterogeneous landscape. A comparative analysis among peer data products revealed that this model exhibited the highest level of correlation when compared to an independently derived expert survey of expected scores. Moreover, differences in correlation were found to be statistically significant in two cases indicating robust model performance. Data products such as these may be leveraged to quantify the nature and extent of human modifications on the landscape, identify highly natural areas for conservation purposes, and may serve as an overarching umbrella for guiding and coordinating large and local-scale planning efforts.     

Contribution of water hyacinth (Eichhornia crassipes (Mart.) Solms) grown under different nutrient conditions to Fe-removal mechanisms in constructed wetlands

Severe contamination of water resources including groundwater with iron (Fe) due to various anthropogenic activities has been a major environmental problem in industrial areas of Sri Lanka. Hence, the use of the obnoxious weed, water hyacinth (Eichhornia crassipes (Mart.) Solms) in constructed wetlands (floating aquatic macrophyte-based plant treatment systems) to phytoremediate Fe-rich wastewaters seems to be an appealing option. Although several studies have documented that hyacinths are good metal-accumulating plants none of these studies have documented the ability of this plant grown under different nutrient conditions to remove heavy metals from wastewaters. This paper, therefore, reports the phytoremediation efficiencies of water hyacinth grown under different nutrient conditions for Fe-rich wastewaters in batch-type constructed wetlands. This study was conducted for 15 weeks after 1-week acclimatization by culturing young water hyacinth plants (average height of 20+/-2cm) in 590L capacity fiberglass tanks under different nutrient concentrations of 1-fold [28 and 7.7mg/L of total nitrogen (TN) and total phosphorous (TP), respectively], 2-fold, 1/2-fold, 1/4-fold and 1/8-fold with synthetic wastewaters containing 9.27Femg/L. Another set-up of hyacinths containing only Fe as a heavy metal but without any nutrients (i.e., 0-fold) was also studied. A mass balance was carried out to investigate the phytoremediation efficiencies and to determine the different mechanisms governing Fe removal from the wastewaters. Fe removal was largely due to phytoremediation mainly through the process of rhizofiltration and chemical precipitation of Fe2O3 and FeOH3 followed by flocculation and sedimentation. However, chemical precipitation was more significant especially during the first 3 weeks of the study. Plants grown in the 0-fold set-up showed the highest phytoremediation efficiency of 47% during optimum growth at the 6th week with a highest accumulation of 6707Femg/kg dry weight. Active effluxing of Fe back to the wastewater at intermittent periods and with time was a key mechanism of avoiding Fe phytotoxicity in water hyacinth cultured in all set-ups. Our study elucidated that water hyacinth grown under nutrient-poor conditions are ideal to remove Fe from wastewaters with a hydraulic retention time of approximately 6 weeks.     

光化学氧化法对阴离子表面活性剂降解的初步研究

本试验采用UV/H2O2光氧化法处理含有较高浓度阴离子表面活性剂（LAS）的模拟废水,研究了H2O2投加量、pH值、光照时间、紫外灯光强对LAS降解率的影响。     

Dynamics of Plains Cottonwood (<Emphasis Type="Italic">Populus deltoides</Emphasis>) Forests and Historical Landscape Change along Unchannelized Segments of the Missouri River,USA

Construction of six large dams and reservoirs on the Missouri River over the last 50–75 years has resulted in major landscape changes and alterations in flow patterns, with implications for riparian forests dominated by plains cottonwood (Populus deltoides). We quantified changes in land cover from 1892–1950s and the 1950s–2006 and the current extent and age structure of cottonwood forests on seven segments (two reservoir and five remnant floodplain) comprising 1127 km (53 %) of the unchannelized upper two-thirds of the Missouri River. Riparian forest area declined by 49 %; grassland 61 %; shrubland 52 %; and sandbar habitat 96 %; while agricultural cropland increased six-fold and river/reservoir surface area doubled from 1892 to 2006. Net rates of erosion and accretion declined between the 1892–1950s and 1950s–2006 periods. Accretion exceeded erosion on remnant floodplain segments, resulting in declines in active channel width, particularly in 1950s–2006. Across all study segments in 2006, most cottonwood stands (67 %) were >50 years old, 22 % were 25–50 years old, and only 10 % were <25 years old. Among stands <50 years old, the higher proportion of 25–50 year old stands represents recruitment that accompanied initial post-dam channel narrowing; while declines in sandbar and shrubland area and the low proportion of stands <25 years old suggest declines in geomorphic dynamism and limited recruitment under recent river management. Future conservation and restoration efforts should focus both on limiting further loss of remnant cottonwood stands and developing approaches to restore river dynamics and cottonwood recruitment processes.     

A comparison of biodegradable municipal waste (BMW) management strategies in Ireland and the Czech Republic and the lessons learned

In order to meet the recycling and recovery targets set forth by the European Union's (EU) Waste and Landfill Directives, both the Irish and Czech governments’ policy on waste management is changing to meet these pressures, with major emphasis being placed upon the management of biodegradable municipal waste (BMW). In particular, the EU Landfill Directive requires reductions in the rate of BMW going to landfill to 35% of 1995 values by 2016 and 2020 for Ireland and the Czech Republic, respectively. In this paper, the strategies of how Ireland and the Czech Republic plan to meet this challenge are compared. Ireland either landfills or exports its waste for recovery, while the Czech Republic has a relatively new waste management infrastructure. While Ireland met the first target of 75% diversion of BMW from landfill by 2010 and preliminary 2012 data indicate that Ireland is on track to meet the 2013 target, the achievement of the 2016 target remains at risk. Indicators that were developed to monitor the Czech Republic's path to meeting the targets demonstrate that it did not meet the first target that was set for 2010 and will probably not meet its 2013 target either. The evaluation reports on the implementation of Waste Management Plan of Czech Republic suggest that the currently applied strategy to divert biodegradable waste from landfill is not effective enough. For both countries, the EU Waste Framework and Landfill Directives will be a significant influence and driver of change in waste management practices and governance over the coming decade. This means that both countries will not only have to invest in infrastructure to achieve the targets, but will also have to increase awareness among the public in diverting this waste at the household level. Improving environmental education is part of increased awareness as it is imperative for citizens to understand the consequences of their actions as affluence continues to grow producing increased levels of waste.     

Rangeland dynamics of southern Ethiopia: (2). Assessment of woody vegetation structure in relation to land use and distance from water in semi-arid Borana rangelands

The structure and advancement of woody vegetation was studied in a semi-arid rangeland of southern Ethiopia under three land-use systems (communal land, a government ranch and a traditional grazing reserve enclosure) and along a distance gradient (near, middle and far) from water sources. A total of 54 woody plant species were identified. Based on the subjective opinions of the pastoralists, 85% of the identified woody plants have forage values to livestock. Cadaba farinsoa, Ormocarpum trichocarpum, Rhus natalensis, Acacia brevispica, Cordia gharaf and Hibiscus sparseaculeatus were reported to have fair to good palatability. Tree equivalent (TE) density of all woody plants combined was greater (P <0.01) in the government ranch (1) 188 TE ha(-1)) and the communal land (1083 TE ha(-1)) than in the traditional grazing reserve (419 TE ha(-1)), whereas this did not vary significantly (P >0.05) along the distance gradient from water. The most important encroaching woody plant species in the study areas were in descending order: Commiphora africana, Acacia drepanolobium, A. brevispica, Acacia. tortilis, Grewia tembensis and Lannea floccosa. The density of individual encroaching woody plant species along the distance gradient from water was not consistent. All encroaching woody species had the highest TE density in the communal land. The prevalence of these species followed the pattern of intensity of use within the communal grazing area. Most of the woody species had the highest abundance in the height class >0-2m regardless of land use and distance gradient from water. This study investigated the advance of severe woody encroachment in the communal and government sites as well as along the distance gradient from water. Some of the important contributing factors that can be suggested are heavy grazing pressure (in both the communal and government sites), expansion of cultivation and reduced mobility of livestock due to settlement of the pastoralists in the communal land.     

Transport of di(2-ethylhexyl)phthalate (DEHP) applied with sewage sludge to undisturbed and repacked soil columns

Municipal sewage sludge is often used on arable soils as a source of nitrogen and phosphorus, but it also contains organic contaminants that may be leached to the ground water. Di(2-ethylhexyl)phthalate (DEHP) is a priority pollutant that is present in sewage sludge in ubiquitous amounts. Column experiments were performed on undisturbed soil cores (20-cm depth x 20-cm diameter) with three different soil types: a sand, a loamy sand, and a sandy loam soil. Dewatered sewage sludge was spiked with 14C-labeled DEHP (60 mg kg(-1)) and bromide (5 g kg(-1)). Sludge was applied to the soil columns either as five aggregates, or homogeneously mixed with the surface layer. Also, two leaching experiments were performed with repacked soil columns (loamy sand and sandy loam soil). The DEHP concentrations in the effluent did not exceed 1.0 microg L(-1), and after 200 mm of outflow less than 0.5% of the applied amount was recovered in the leachate in all soils but the sandy loam soil with homogeneous sludge application (up to 3.4% of the applied amount recovered). In the absence of macropore flow, DEHP in the leachate was primarily sorbed to mobilized dissolved organic macromolecules (DOM, 30.3 to 81.3%), while 2.4 to 23.6% was sorbed to mobilized mineral particles. When macropore flow occurred, this changed to 16.5 to 37.4% (DOM) and 36.9 to 40.6% (mineral particles), respectively. The critical combination for leaching of considerable amounts of DEHP was homogeneous sludge application and a continuous macropore structure.     

Application of adaptive heuristic criticism control (AHCC) to dye wastewater

This paper presents an experimental application of AHCC to study the coagulation process of wastewater treatment in a dye plant. Also this study includes a series of tests in which an AHCC control was used for pH control. The performance results of the AHCC controller are compared with the results obtained by using a conventional proportional-integral-derivative (PID) algorithm. It is useful to compare PID with AHCC to illustrate the extreme range of the nonlinearity of the dye wastewater treatment process. Although the removal of pollutants from wastewater is similar with AHCC and PID, our results show excellent AHCC performance in the region where conventional PID control fails.     

Reuse of sugarcane bagasse ash (SCBA) to produce ceramic materials

Sugarcane bagasse ash (SCBA) is a residue resulting from the burning of bagasse in boilers in the sugarcane/alcohol industry. SCBA has a very high silica concentration and contains aluminum, iron, alkalis and alkaline earth oxides in smaller amounts. In this work, the properties of sintered ceramic bodies were evaluated based on the concentration of SCBA, which replaced non-plastic material. The ash was mixed (up to 60 wt%) with a clayed raw material that is used to produce roof tiles. Prismatic probes were pressed and sintered at different temperatures (up to 1200 °C). Technological tests of ceramic probes showed that the addition of ash has little influence on the ceramic properties up to 1000 °C. X-ray diffraction and thermal analysis data showed that, above this temperature the ash participates in the sintering process and in the formation of new important phases. The results reported show that the reuse of SCBA in the ceramic industry is feasible.