From pattern to process: landscape fragmentation and the analysis of land use/land cover change

The incorporation of landscape ecological and fragmentation analyses within remote sensing science has expanded the inferential capabilities of such research. This issue presents a series of papers on the use of landscape ecological techniques to explore the relationship between land cover and land use spatial pattern and process in an international, comparative context. Methodologically, researchers seek to link spatial pattern to land use process by integrating geographic information systems (GIS), socio-economic, and remote sensing techniques with landscape ecological approaches. This issue brings together papers at the forefront of this research effort, and illustrates the diversity of methods necessary to evaluate the complex linkages between pattern and process in landscapes across the world. The analyses focus on major forces interacting at the earth’s surface, such as the interface of agricultural and urban land, agriculture and forestry, and other pertinent topics dealing with environmental policy and management. Empirical analyses stem from many different ecological, social and institutional contexts within the Americas, Africa, and Asia.     

Variability in climate change simulations affects needed long-term riverine nutrient reductions for the Baltic Sea

Changes to runoff due to climate change may influence management of nutrient loading to the sea. Assuming unchanged river nutrient concentrations, we evaluate the effects of changing runoff on commitments to nutrient reductions under the Baltic Sea Action Plan. For several countries, climate projections point to large variability in load changes in relation to reduction targets. These changes either increase loads, making the target more difficult to reach, or decrease them, leading instead to a full achievement of the target. The impact of variability in climate projections varies with the size of the reduction target and is larger for countries with more limited commitments. In the end, a number of focused actions are needed to manage the effects of climate change on nutrient loads: reducing uncertainty in climate projections, deciding on frameworks to identify best performing models with respect to land surface hydrology, and increasing efforts at sustained monitoring of water flow changes.     

A model of surface fire,climate and forest pattern in the Sierra Nevada,California

A spatially explicit forest gap model was developed for the Sierra Nevada, California, and is the first of its kind because it integrates climate, fire and forest pattern. The model simulates a forest stand as a grid of 15×15 m forest plots and simulates the growth of individual trees within each plot. Fuel inputs are generated from each individual tree according to tree size and species. Fuel moisture varies both temporally and spatially with the local site water balance and forest condition, thus linking climate with the fire regime. Fires occur as a function of the simulated fuel loads and fuel moisture, and the burnable area is simulated as a result of the spatially heterogeneous fuel bed conditions. We demonstrate the model’s ability to couple the fire regime to both climate and forest pattern. In addition, we use the model to investigate the importance of climate and forest pattern as controls on the fire regime. Comparison of model results with independent data indicate that the model performs well in several areas. Patterns of fuel accumulation, climatic control of fire frequency and the influence of fuel loads on the spatial extent of fires in the model are particularly well-supported by data. This model can be used to examine the complex interactions among climate, fire and forest pattern across a wide range of environmental conditions and vegetation types. Our results suggest that, in the Sierra Nevada, fuel moisture can exert an important control on fire frequency and this control is especially pronounced at sites where most of the annual precipitation is in the form of snow. Fuel loads, on the other hand, may limit the spatial extent of fire, especially at elevations below 1500 m. Above this elevation, fuel moisture may play an increasingly important role in limiting the area burned.     

On the possibility for separate determination of pyrolyzed products (soot and polycyclic aromatic hydrocarbons) in aerosols by EPR spectrometry

The present paper demonstrates the applicability of EPR spectrometry for separate estimation of soot (EC) and polycyclic aromatic hydrocarbons (PAH) in aerosols. The content of EC is obtained directly because of their paramagnetic properties whereas diamagnetic PAH, adsorbed on the soot, are converted to paramagnetic forms by oxidation over silica/alumina catalyst. In order to fulfill the goal of our study at this stage only few samples of aerosols are investigated after being collected at four different locations: near and distant to motorway, office and cafeteria. The obtained results show that the quantities of soot and PAH in all cases are μg m⁻³. However, their content varies depending on the place of sample collection. The following order of decreasing soot quantity is found: motorway>urban air>cafeteria>office whereas for PAH the order is cafeteria≅motorway>urban air>office. The obtained results are discussed in the light of the pollution sources at the sampling places.     

Characteristic number size distribution of aerosol during Asian dust period in Korea

The size-separated number concentrations of aerosols ranging from 0.3 to 25 μm were observed in Seoul and Anmyon Island in the west coast of Korea during Asian dust period in Spring 1998. During the heavy dust period, the number size distributions of aerosols observed in both places were characterized by decreases in small size<0.5 μm and increase in large size between 1.35 and 10 μm. For particles in this range, there was a good correlation between number concentrations observed in both two places. The number of coarse particles >10 μm showed a distinct diurnal variation without a significant change in amplitude, which was more pronounced in Seoul. It suggests that coarse particles were more affected by local sources. Trajectories back in time showed that the air collected in Korea during dust period originated from desert regions in the central part of China. From these results, it was evident that increased particles in the range of 1.35–10 μm during dust source period represented mineral components, which originated possibly from the dust source regions.     

Ambient air quality of two metropolitan cities of Pakistan and its health implications

The present study reports findings on TSP loading in the ambient air of two major cities in Pakistan – Karachi and Islamabad. Data for TSP were collected at one site in Karachi and two in Islamabad between 10 December 1998 and 08 January 1999. This article reports one of the highest TSP loadings recorded so far in any megacity of the world. During the study period, average daily TSP concentrations at the Karachi site ranged from 627 to 938 μg m⁻³ with a mean of 668 μg m⁻³. On four occasions TSP concentrations were >1000 μg m⁻³ (range 1031–1736 μg m⁻³). At the Islamabad sampling site in close proximity to the city's industrial sector, daily TSP concentrations varied in the range of 428–998 μg m⁻³ (mean 691 μg m⁻³). Even at a relatively remote site of the city (Saidpur), TSP loading was high (range 145–448 μg m⁻³; mean 275 μg m⁻³). By virtue of the WHO definition, the 24-h average TSP concentrations in a busy commercial site in Karachi and in the vicinity of an industrial sector in Islamabad were in “exceedance” by a factor of 4–8. At Saidpur, the remote site, the 24-h average TSP loading exceeded the WHO guideline of 120 μg m⁻³ by a factor of 1.2–3.7.     

Monitoring of carbon monoxide in residences with bulk wood pellet storage in the Northeast United States

The interest in biomass fuel is continuing to expand globally and in the northeastern United States as wood pellets are becoming a primary source of fuel for residential and small commercial systems. Wood pellets for boilers are often stored in basement storage rooms or large bag-type containers. Due to the enclosed nature of these storage areas, the atmosphere may exhibit increased levels of carbon monoxide. Serious accidents in Europe have been reported over the last decade in which high concentrations of carbon monoxide (CO) have been found in or near bulk pellet storage containers. The aim of this study was to characterize the CO concentrations in areas with indoor storage of bulk wood pellets. Data was obtained over approximately 7 months (December 2013 to June 2014) at 25 sites in New Hampshire and Massachusetts: 16 homes using wood pellet boilers with indoor pellet storage containers greater than or equal to 3 ton capacity; 4 homes with wood pellet heating systems with outdoor pellet storage; 4 homes using other heating fuels; and a university laboratory site. CO monitors were set up in homes to collect concentrations of CO in the immediate vicinity of wood pellet storage containers, and data were then compared to those of homes using fossil fuel systems. The homes monitored in this study provided a diverse set of housing stock spanning two and a half centuries of construction, with homes built from 1774 to 2013, representing a range of air exchange rates. The CO concentration data from each home was averaged hourly and then compared to a threshold of 9 ppm. While concentrations of CO were generally low for the homes studied, the need to properly design storage locations for pellets is and will remain a necessary component of wood pellet heating systems to minimize the risk of CO exposure.

Implications: This paper is an assessment of carbon monoxide (CO) exposure from bulk wood pellet storage in homes in New Hampshire and Massachusetts. Understanding the CO concentrations in homes allows for better designs for storage bins and ventilation for storage areas. Hence, uniform policies for stored wood pellets in homes, schools, and businesses can be framed to ensure occupant safety. Currently in New York State rebates for the installation of wood pellet boilers are only provided if the bulk pellet storage is outside of the home, yet states such as New Hampshire, Vermont, and Maine currently do not have these restrictions.     

Advantages of Geographically Weighted Regression for Modeling Benthic Substrate in Two Greater Yellowstone Ecosystem Streams

Stream habitat assessments are commonplace in fish management, and often involve nonspatial analysis methods for quantifying or predicting habitat, such as ordinary least squares regression (OLS). Spatial relationships, however, often exist among stream habitat variables. For example, water depth, water velocity, and benthic substrate sizes within streams are often spatially correlated and may exhibit spatial nonstationarity or inconsistency in geographic space. Thus, analysis methods should address spatial relationships within habitat datasets. In this study, OLS and a recently developed method, geographically weighted regression (GWR), were used to model benthic substrate from water depth and water velocity data at two stream sites within the Greater Yellowstone Ecosystem. For data collection, each site was represented by a grid of 0.1 m² cells, where actual values of water depth, water velocity, and benthic substrate class were measured for each cell. Accuracies of regressed substrate class data by OLS and GWR methods were calculated by comparing maps, parameter estimates, and determination coefficient r ². For analysis of data from both sites, Akaike’s Information Criterion corrected for sample size indicated the best approximating model for the data resulted from GWR and not from OLS. Adjusted r ² values also supported GWR as a better approach than OLS for prediction of substrate. This study supports GWR (a spatial analysis approach) over nonspatial OLS methods for prediction of habitat for stream habitat assessments.