Land use impact assessment in the construction sector: an analysis of LCIA models and case study application

Purpose

Land use is a potentially important impact category in life cycle assessment (LCA) studies of buildings. Three research questions are addressed in this paper: Is land use a decisive factor in the environmental impact of buildings?; Is it important to include the primary land use of buildings in the assessment?; and How does the environmental performance of solid structure and timber frame dwellings differ when assessed by distinct available models for quantifying land use impacts?

Methods

This paper compares several operational land use impact assessment models, which are subsequently implemented in an LCA case study comparing a building constructed using timber frame versus a solid structure. Different models were used for addressing the different research questions.

Results and discussion

The results reveal that contrasting decisions may be supported by LCA study results, depending on whether or not and how land use is included in the assessment. The analysis also highlights the need to include the building land footprint in the assessment and to better distinguish building locations in current land use impact assessment models.

Conclusions

Selecting land use assessment models that are most appropriate to the goals of the study is recommended as different models assess different environmental issues related to land use. In general, the combination of two land use assessment methods for buildings is recommended, i.e. soil organic matter (SOM) of Milà i Canals and Eco-indicator 99.     

Understanding landscape patterns of temporal variability in avian populations to improve environmental impact assessments

It is recognized that wildlife populations exhibit spatial and temporal variability in patterns of species richness across heterogeneous landscapes. This phenomenon can prove problematic for environmental practitioners when attempting to complete comprehensive environmental assessments (EAs) with limited field surveys. A better understanding of regional spatio-temporal patterns in population dynamics should enhance site-level decision-making. In this study, the variability of seasonal data across the Credit River Watershed, southern Ontario, is assessed for a hierarchy of conservation measures including species richness, and two conservation wildlife response guilds based on primary habitat and area sensitivity. Bird populations were monitored at 24 forest monitoring plots across the watershed by the authors twice a season from 2003 to 2010 following the protocol of Environment Canada's Forest Bird Monitoring Program. The monitoring plots are located within four land management zones identified as 1) urban, 2) transitional, 3) escarpment and 4) rural. Data from the monitoring program are used to compare species richness among plots across the watershed and among land management zones. In addition, the variability of records from each plot over the 8 year period was determined by means of the Coefficient of Variation (CV) statistic. The mean variability of these records at each site within each land management zone was determined in order to assess whether the temporal variability of bird records might affect the integrity of short term assessments. Finally, a one-way ANOVA was applied to learn whether the result of short-term assessments may be further compounded by differences in the response of selected bird guilds to landscape heterogeneity. The results show that there is a significant difference in mean richness of forest birds among the four management zones. The ANOVAs indicate that significant difference is due to the temporal variability of a) breeding forest interior birds rather than edge birds or generalist species and b) breeding area sensitive species rather than area non-sensitive species. Recommendations are made that environmental assessments targeting forest interior bird populations need to plan sampling strategies that recognize this variability, especially for sites within the transitional and urban zones. Planning in the transition or urbanizing landscape should incorporate landscape ecology principles to sustain current levels of richness in forest species.     

Integrating dynamic environmental predictors and species occurrences: Toward true dynamic species distribution models

While biological distributions are not static and change/evolve through space and time, nonstationarity of climatic and land‐use conditions is frequently neglected in species distribution models. Even recent techniques accounting for spatiotemporal variation of species occurrence basically consider the environmental predictors as static; specifically, in most studies using species distribution models, predictor values are averaged over a 50‐ or 30‐year time period. This could lead to a strong bias due to monthly/annual variation between the climatic conditions in which species' locations were recorded and those used to develop species distribution models or even a complete mismatch if locations have been recorded more recently. Moreover, the impact of land‐use change has only recently begun to be fully explored in species distribution models, but again without considering year‐specific values. Excluding dynamic climate and land‐use predictors could provide misleading estimation of species distribution. In recent years, however, open‐access spatially explicit databases that provide high‐resolution monthly and annual variation in climate (for the period 1901–2016) and land‐use (for the period 1992–2015) conditions at a global scale have become available. Combining species locations collected in a given month of a given year with the relative climatic and land‐use predictors derived from these datasets would thus lead to the development of true dynamic species distribution models (D‐SDMs), improving predictive accuracy and avoiding mismatch between species locations and predictor variables. Thus, we strongly encourage modelers to develop D‐SDMs using month‐ and year‐specific climatic data as well as year‐specific land‐use data that match the period in which species data were collected.     

Economic and environmental impact assessments of a stand-alone napier grass-fired combined heat and power generation system in the southeastern US

The International Journal of Life Cycle Assessment - Napier grass, one of the high yield perennial energy crops can be grown on marginal lands with minimal inputs, but with increased soil carbon...     

The impact of environmental fluctuations on structured discrete time population models: resonance, synchrony and threshold behaviour

External forcing of a discrete time ecological system does not just add variation to existing dynamics but can change the dynamics. We study the mechanisms that can bring this about, focusing on the key concepts of excitation and suppression which emerge when analysing the power spectra of the system in linear approximation. Excitation, through resonance between the system dynamics and the external forcing, is the greater the closer the system is to the boundary of the stability region. This amplification means that the extinction of populations becomes possible sooner than expected and, conversely, invasion can be significantly delayed. Suppression and the consequent redistribution of power within the spectrum proves to be a function both of the connectivity of the network graph of the system and the way that external forcing is applied to the system. It is also established that colour in stochastic forcing can have a major impact, by enhancing resonance and by greater redistribution of power. This can mean a higher risk of extinction through larger fluctuations in population numbers and a higher degree of synchrony between populations. The implications of external forcing for stage-structured species, for populations in competition and for trophic web systems are studied using the tools and concepts developed in the paper.     

Responses of grassland production to single and multiple global environmental changes

In this century, increasing concentrations of carbon dioxide (CO₂) and other greenhouse gases in the Earth's atmosphere are expected to cause warmer surface temperatures and changes in precipitation patterns. At the same time, reactive nitrogen is entering natural systems at unprecedented rates. These global environmental changes have consequences for the functioning of natural ecosystems, and responses of these systems may feed back to affect climate and atmospheric composition. Here, we report plant growth responses of an ecosystem exposed to factorial combinations of four expected global environmental changes. We exposed California grassland to elevated CO₂, temperature, precipitation, and nitrogen deposition for five years. Root and shoot production did not respond to elevated CO₂ or modest warming. Supplemental precipitation led to increases in shoot production and offsetting decreases in root production. Supplemental nitrate deposition increased total production by an average of 26%, primarily by stimulating shoot growth. Interactions among the main treatments were rare. Together, these results suggest that production in this grassland will respond minimally to changes in CO₂ and winter precipitation, and to small amounts of warming. Increased nitrate deposition would have stronger effects on the grassland. Aside from this nitrate response, expectations that a changing atmosphere and climate would promote carbon storage by increasing plant growth appear unlikely to be realized in this system.     

Toward sustainable and comprehensive control of schistosomiasis in China: lessons from Sichuan

Triggered by a fascinating publication in the New England Journal of Medicine detailing China's new multi-pronged strategy to control and eventually interrupt the transmission of Schistosoma japonicum, this PLoS Neglected Tropical Diseases Debate critically examines the generalizability and financial costs of the studies presented from the marshlands of the lake region. Edmund Seto from the University of California and colleagues emphasize that the epidemiology and control of schistosomiasis varies according to the social-ecological context. They conjecture that the successful intervention packages piloted in the lake region is not fully fit for the hilly and mountainous environments in Sichuan and Yunnan provinces, and hence call for more flexible, setting-specific, and less expensive control strategies. In response, Xiao-Nong Zhou from the National Institute of Parasitic Diseases at the Chinese Center of Disease Control and Prevention and colleagues explain the steps from designing pilot studies to the articulation and implementation of a new national control strategy through a careful process of scaling-up and adaptations. Finally, the two opponents converge. The need for integrated, intersectoral, and setting-specific control measures is stressed, supported by rigorous surveillance and continuous research. Experiences and lessons from China are important for shaping the schistosomiasis elimination agenda.     

Bird sensitivity to disturbance as an indicator of forest patch conditions: An issue in environmental assessments

An Environmental Assessment (EA) is one of the steps within the Environmental Impact Assessment process. Birds are often used in EA to help decision makers evaluate potential human impacts from proposed development activities. A “sensitivity to human disturbance” index, created by Parker III et al. (1996) for all Neotropical species, is commonly considered an ecological indicator. However, this parameter was created subjectively and, for most species, there have been no rigorous field test to validate its effectiveness as such. Therefore, in this study, we aim to: (1) evaluate if, at the local scale, birds from forest patches in a human-modified landscape (HML) may differ in sensitivity from Parker's sensitivity classification; (2) evaluate the effectiveness of the species richness value at each sensitivity level as an ecological indicator; (3) gather information on how often and in which manner Parker's classification has been used in EA. To do so, bird sampling was performed in eight forest patches in a HML over one year. Then, we created a local sensitivity to disturbance using information about threat, endemism, spatial distribution and relative abundance of all species in the study area. We found that 37% of the forest birds showed different local sensitivity levels when compared with Parker's classification. Our results show that only the richness of high-sensitivity species from our local classification fitted the ecological indicator assumptions helping the environmental conditions evaluation of the studied patches. We conclude that species richness of each Parker's bird sensitivity levels do not necessarily perform as an ecological indicator at the local scale, and particularly in HML. Nevertheless, Parker's Neotropical bird sensitivity classification was used in 50% of EA we reviewed. In these, 76% assumed that it was an accurate ecological indicator of the local forest conditions for birds. The lack of clear criteria used in Parker's classification allows diverse interpretations by ornithologists, and there is no agreement about the ecological meaning of each sensitivity level and what environmental conditions each level may indicate of. Therefore, the use of Parker's classification in EA may jeopardize accurate interpretations of proposed anthropogenic impacts. Furthermore, because a bird species’ sensitivity often varies between locations, we argue that Parker's generalized classification of bird sensitivity should not be used as an indicator of forest environmental conditions in EA throughout HMLs in Neotropics. Rather, local bird ecological indices should be explored, otherwise, erroneous predictions of the anthropogenic impacts will continue to be common.     

Visibility of the impact of environmental noise: a response to Kaitala and Ranta

Based on simulation modelling, Kaitala and Ranta (2001 Proc. R. Soc. Lond. B 268, 1769-1774) have argued that detecting the statistical relationships between environmental variability and population fluctuations will be difficult. However, their study was limited in that only one pattern of density dependence and one detection method were used. Here, we show that their conclusion is in part a consequence of their choice of population model and in part a consequence of using relatively weak or inappropriate statistical methods. Other patterns of density dependence respond differently to environmental fluctuations, and the impact of the disturbance on these is clearly visible using their methods. For some patterns of population dynamics, environmental impacts are more readily detectable by correlating running-average environmental conditions with the population time-series or by correlating the first differences of the population time-series with environmental noise. When more appropriate statistical methods are used, environmental forcing is detectable in the majority of cases used by Kaitala and Ranta. The interplay between environmental stochasticity and density-dependent population growth means that there is no single best method to detect the influence of environmental forcing, even when population dynamics are approximately linear. But environmental forcing will often be detectable, contrary to Kaitala and Ranta's assertions.     

Toward a more accurate quantitation of the activity of recombinant retroviruses: alternatives to titer and multiplicity of infection

In this paper, we present a mathematical model with experimental support of how several key parameters govern the adsorption of active retrovirus particles onto the surface of adherent cells. These parameters, including time of adsorption, volume of virus, and the number, size, and type of target cells, as well as the intrinsic properties of the virus, diffusion coefficient, and half-life (t1/2), have been incorporated into a mathematical expression that describes the rate at which active virus particles adsorb to the cell surface. From this expression, we have obtained estimates of Cvo, the starting concentration of active retrovirus particles. In contrast to titer, Cvo is independent of the specific conditions of the assay. The relatively slow diffusion (D = 2 x 10(-8) cm2/s) and rapid decay (t1/2 = 6 to 7 h) of retrovirus particles explain why Cvo values are significantly higher than titer values. Values of Cvo also indicate that the number of defective particles in a retrovirus stock is much lower than previously thought, which has implications especially for the use of retroviruses for in vivo gene therapy. With this expression, we have also computed AVC (active viruses/cell), the number of active retrovirus particles that would adsorb per cell during a given adsorption time. In contrast to multiplicity of infection, which is based on titer and is subject to the same inaccuracies, AVC is based on the physicochemical parameters of the transduction assay and so is a more reliable alternative.     

Toward a more accurate quantitation of the activity of recombinant retroviruses: alternatives to titer and multiplicity of infection

In this paper, we present a mathematical model with experimental support of how several key parameters govern the adsorption of active retrovirus particles onto the surface of adherent cells. These parameters, including time of adsorption, volume of virus, and the number, size, and type of target cells, as well as the intrinsic properties of the virus, diffusion coefficient, and half-life (t(1/2)), have been incorporated into a mathematical expression that describes the rate at which active virus particles adsorb to the cell surface. From this expression, we have obtained estimates of C(vo), the starting concentration of active retrovirus particles. In contrast to titer, C(vo) is independent of the specific conditions of the assay. The relatively slow diffusion (D = 2 x 10(-8) cm(2)/s) and rapid decay (t(1/2) = 6 to 7 h) of retrovirus particles explain why C(vo) values are significantly higher than titer values. Values of C(vo) also indicate that the number of defective particles in a retrovirus stock is much lower than previously thought, which has implications especially for the use of retroviruses for in vivo gene therapy. With this expression, we have also computed AVC (active viruses/cell), the number of active retrovirus particles that would adsorb per cell during a given adsorption time. In contrast to multiplicity of infection, which is based on titer and is subject to the same inaccuracies, AVC is based on the physicochemical parameters of the transduction assay and so is a more reliable alternative.     

Porcine genomics delivers new tools and results: this little piggy did more than just go to market

The past decade has yielded new tools for pig geneticists and breeders thanks to the considerable developments resulting from efforts to map the pig genome. The pig genetic linkage map now has nearly 5000 loci including several hundred genes, microsatellites and amplified fragment length polymorphisms (AFLP) markers. Using tools that include somatic cell hybrid panels and radiation hybrid panels, the physical genetic map is also growing rapidly and has over 4000 genes and markers. Scientists using both exotic and commercial breeds for quantitative trait loci (QTL) scans and candidate gene analyses have identified a number of important chromosomal regions and individual genes associated with growth rate, leanness, feed intake, meat quality, litter size and disease resistance. Using marker-assisted selection (MAS) the commercial pig industry is actively incorporating these gene markers and traditional performance information to improve traits of economic importance in pig production. Researchers now have novel tools including pig gene arrays and advanced bioinformatics that are being exploited to find new candidate genes and to advance the understanding of gene function in the pig. Sequencing of the pig genome has been initiated and further sequencing is now being considered. Advances in pig genomics and directions for future research and the implications to both the pig industry and human health are reviewed.