4200 years of pine-dominated upland forest dynamics in west-central Mexico: human or natural legacy?

The pine-dominated forests of west-central Mexico are internationally recognized for their high biodiversity, and some areas are protected through various conservation measures including prohibition of human activity. In this region, however, there is evidence for human settlement dating back to ca. AD 1200. It is therefore unclear whether the present forest composition and structure are part of a successional stage following use by indigenous human populations during the past, or due to natural processes, such as climate. We present a study reconstructing the vegetation dynamics of pine-dominated forest over the past 4200 years using paleoecological techniques. Results from fossil pollen and charcoal indicate that, in this region, pine-dominated forests are the native vegetation type and not anthropogenically derived secondary succession. The predominant driving mechanism for the expansion of pine-dominated forest appears to be intervals of aridity and naturally induced burning. A close association is noted between pine abundance and longer-term climatic trends, including intervals of aridity between ca. 4200 and 2500, 1200 and 850, and 500 and 200 cal yr BP and shorter-term trends. Evident periodicity occurs in pine and Poaceae abundance every 80 years. These short-term quasi-periodic oscillations have been recorded in a number of lake and ocean sediments in Mexico and are thought to be linked to solar forcing resulting in drought cycles that occur at approximately the same time intervals.     

Estimating the economic,social and environmental impacts of wildfires in Australia

It is often said that bushfires are a fact of life in Australia. While Australian communities will always be affected by the impacts of bushfires, there is an element of human involvement that makes at least some bushfires avoidable. In Australia more bushfires are started by deliberate lighting than are caused by lightning or other natural sources. This creates an element of criminality in relation to bushfires which includes the establishment of bushfire arson as a serious criminal offence. The author presents a motive-based typology of deliberately lit bushfires and argues that a greater understanding of the reasons why people light bushfires can help prevention, investigation and treatment of offenders.     

Estimating PAH sources in harbor sediments using diagnostic ratios

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous in the global environment and are subsequently transported into aquatic sediments. As PAHs are formed by various processes, source identification using diagnostic ratios can provide insight to PAH emission sources to distinguish between pyrogenic and petrogenic PAH sources. PAH diagnostic ratios were applied as a forensic source apportionment technique to assess aggregate historical sediment data from 31 small craft harbors (SCHs) across Nova Scotia, Canada. Multiple diagnostic ratios suggest that PAHs present in Nova Scotia SCH sediments are pyrogenic (combustion) in origin, while consistently suggesting that coal‐related PAH sources are potential dominant specific sources. National Institute of Standards and Technology Standard Reference Materials (SRMs) were used as reference for coal tar, urban dust, and diesel exhaust particulates in ratio applications. The SRM for coal tar was most similar to Nova Scotia SCH sediments in multiple ratio applications. Diagnostic ratio results were corroborated by comparing the PAH profile of sediments to source profiles from the literature. Results indicate that Nova Scotia SCH sediments follow global trends by exhibiting a dominant pyrogenic PAH signature, and the specific coal‐related PAH signature of Nova Scotia SCH sediments may be influenced by contamination inputs related to historical industrial coal mining and combustion activities in the province.     

Assessing the Impacts of Future Climate Change on Protected Area Networks: A Method to Simulate Individual Species' Responses

Global climate change, along with continued habitat loss and fragmentation, is now recognized as being a major threat to future biodiversity. There is a very real threat to species, arising from the need to shift their ranges in the future to track regions of suitable climate. The Important Bird Area (IBA) network is a series of sites designed to conserve avian diversity in the face of current threats from factors such as habitat loss and fragmentation. However, in common with other networks, the IBA network is based on the assumption that the climate will remain unchanged in the future. In this article, we provide a method to simulate the occurrence of species of conservation concern in protected areas, which could be used as a first-step approach to assess the potential impacts of climate change upon such species in protected areas. We use species-climate response surface models to relate the occurrence of 12 biome-restricted African species to climate data at a coarse (quarter degree-degree latitude-longitude) resolution and then intersect the grid model output with IBA outlines to simulate the occurrence of the species in South African IBAs. Our results demonstrate that this relatively simple technique provides good simulations of current species' occurrence in protected areas. We then use basic habitat data for IBAs along with habitat preference data for the species to reduce over-prediction and further improve predictive ability. This approach can be used with future climate change scenarios to highlight vulnerable species in IBAs in the future and allow practical recommendations to be made to enhance the IBA network and minimize the predicted impacts of climate change.     

Monitoring and Source Apportionment of Particulate Matter near a Large Phosphorus Production Facility

ABSTRACT

A source apportionment study was conducted to identify sources within a large elemental phosphorus plant that contribute to exceedances of the National Ambient Air Quality Standards (NAAQS) for 24-hr PM₁₀. Ambient data were collected at three monitoring sites from October 1996 through July 1999, and included the following: 24-hr PM₁₀ mass, 24-hr PM_2.5 and PM_10–2.5 mass and chemistry, continuous PM₁₀and PM_2.5 mass, continuous meteorological data, and wind-direction-resolved PM_2.5 and PM₁₀ mass and chemistry. Ambient-based receptor modeling and wind-directional analysis were employed to help identify major sources or source locations and source contributions. Fine-fraction phosphate was the dominant species observed during PM₁₀ exceedances, though in general, re-suspended coarse dusts from raw and processed materials at the plant were also needed to create an exceedance. Major sources that were identified included the calciners, the CO flares, process-related dust, and electric-arc furnace operations.     

Understanding Conceptual Climate Change Meanings and Preferences of Multi-Actor Professional Leadership in New York

This article sets out to evaluate the range of meanings and preferences for the concepts of adaptation, resilience, mitigation and coping of a variety of professionals in New York who are undertaking leadership positions in developing climate change policies and practices. This article positions a normative set of simplified meanings for each of the aforementioned concepts based on a review of existing literature. Utilizing a survey, these normative meanings are evaluated by and between the: (a) concepts and meanings; (b) concepts and applications and (c) applications and preferences, as applied to various risk-based scenarios ranging from sea-level rise to heat waves. This survey tests the hypotheses that the respondents: (i) are unable to consistently match the concept of resiliency with the normative meanings or applications: and (ii) will not consistently show a preference for resilience applications or outcomes ahead of other concepts. The results of the survey confirm both hypotheses, which is demonstrative of the inadequacy of the current framework dominated by a narrowly defined framework for resilience. It is anticipated that the results of this article will advance an argument for the necessity to develop consistent meanings for concepts which bridge the scientific, policy and popular domains.     

Consumer willingness to pay for organic and locally grown produce on Dominica: insights into the potential for an “Organic Island”

With the intent of improving agricultural revenues and solidifying her place as an ecotourism destination, it has been proposed that the island nation of The Commonwealth of Dominica convert all agriculture to organic production. This study explores Dominica’s current and potential domestic demand for organic and/or “locally grown” produce. Surveys were conducted with Dominican consumers to assess their opinions and willingness to pay for these products, and evaluated using a maximum likelihood estimation procedure. On average, Dominican consumers are willing to pay 17.5 % more for organic, and 12 % more for locally grown, produce. These results were varied significantly across demographic segments of the sampled population, respondent tastes and preferences, the health status of their family, and the extent to which they were early adopters of new products. Despite several expected challenges of a successful transition to organic, implementation of this policy may offer a net positive welfare increase for Dominica’s permanent residents. Results from this analysis suggest that, from the perspective of domestic consumers, Dominica should continue to pursue the possibility of becoming an “Organic Island.”     

Paying for heritage: what price for durham cathedral?

This study assesses the amount individuals voluntarily contribute when visiting a Cathedral where no charge is made for entry. Contingent valuation methods are used to estimate the maximum individuals would be willing to pay if an entry charge was imposed, the changes in visit rates which would ensue at different price levels and the maximum revenue the Cathedral could be expected to collect by charging an entry fee.