Evaluating Quality of Life, Economic Vulnerabilities, and Drivers of Ecosystem Change

We examined regional conditions and trends related to quality of life and potential vulnerabilities of these factors to changes in the condition of natural resources in the Mid-Atlantic Region, USA. We selected a variety of variables on economic and socio-demographic conditions that demonstrate links between the condition of natural areas and human concerns and that quantify dependencies on resources. We extracted data from economic and population census databases for counties within the study area and present a subset of results of the cluster analyses used to describe condition and potential risks due to distinct combinations of variables. We found that the same variables used to judge quality of life were often correlated with increasing population and thus were likely to be related to land pressures and risks to natural resources. Within the region, economic dependence on resource-harvesting industries such as forestry and fisheries was low (less than 4% of total earnings at most), however, the potential for natural amenities to attract residents appeared to be growing as the self-employed and otherwise mobile people settled in areas with affordable housing and natural amenities. Suburban residential spread had been occurring in both the close-in and distant suburbs of the region's urban areas and some rural, growth appeared to be driven, in part, by businesses migrating to suburbs. Further work is needed to tease apart causal factors for the trends we observed, but correlations clearly existed in some areas between increasing populations and quality of natural surroundings.     

Mathematical Methods for Spatially Cohesive Reserve Design

The problem of designing spatially cohesive nature reserve systems that meet biodiversity objectives is formulated as a nonlinear integer programming problem. The multiobjective function minimises a combination of boundary length, area and failed representation of the biological attributes we are trying to conserve. The task is to reserve a subset of sites that best meet this objective. We use data on the distribution of habitats in the Northern Territory, Australia, to show how simulated annealing and a greedy heuristic algorithm can be used to generate good solutions to such large reserve design problems, and to compare the effectiveness of these methods.     

A comparative analysis of colour preferences in temperate and tropical social bees

The spontaneous occurrence of colour preferences without learning has been demonstrated in several insect species; however, the underlying mechanisms are still not understood. Here, we use a comparative approach to investigate spontaneous and learned colour preferences in foraging bees of two tropical and one temperate species. We hypothesised that tropical bees utilise different sets of plants and therefore might differ in their spontaneous colour preferences. We tested colour-naive bees and foragers from colonies that had been enclosed in large flight cages for a long time. Bees were shortly trained with triplets of neutral, UV-grey stimuli placed randomly at eight locations on a black training disk to induce foraging motivation. During unrewarded tests, the bees’ responses to eight colours were video-recorded. Bees explored all colours and displayed an overall preference for colours dominated by long or short wavelengths, rather than a single colour stimulus. Naive Apis cerana and Bombus terrestris showed similar choices. Both inspected long-wavelength stimuli more than short-wavelength stimuli, whilst responses of the tropical stingless bee Tetragonula iridipennis differed, suggesting that resource partitioning could be a determinant of spontaneous colour preferences. Reward on an unsaturated yellow colour shifted the bees’ preference curves as predicted, which is in line with previous findings that brief colour experience overrides the expression of spontaneous preferences. We conclude that rather than determining foraging behaviour in inflexible ways, spontaneous colour preferences vary depending on experimental settings and reflect potential biases in mechanisms of learning and decision-making in pollinating insects.     

The value of time in recreation benefit studies

This paper examines the role of time costs—both on-site and travel—in models describing recreation behavior, and draws implications for the travel-cost approach to recreation site benefit estimation. The analysis shows that both recreation and travel time are costly. The latter can be valued in terms of its scarcity value, but the former may be most appropriately valued in terms of the “alue of travel time saved.” Although there are cases in which on-site time costs need not be explicitly considered in recreation benefit models, it is not clear such cases are the rule rather than the exception. Suggestions are made for measuring on-site and travel time costs.     

Using markets for land preservation: Results of a TDR program

This paper reviews different approaches to using transferable development rights (TDRs) as a way to preserve rural lands in the face of development pressure. One TDR program is examined in detail, that of Calvert County, Maryland, which has had an active TDR market since the mid-1980s. This program uses TDRs as a key policy tool for achieving a total amount of preserved acreage in the county, and for providing incentives for preservation in some areas and development in others. The paper examines both the early difficulties in developing participation in the program, and the events that lead eventually to an active TDR market. It assesses the workings of the market including factors that influence the demand and supply of TDRs, the movement of prices over time, and the location of preserved areas and of additional developed areas. The study found that the program is achieving many of the county's land preservation goals because of the high level of activity in the TDR market. However, most of the additional density is being channeled into rural areas with underlying low-density zoning.     

Moisture effects in heat transfer through clothing systems for wildland firefighters.

Wildland firefighters work in unfavourable environments involving both heat and moisture. Moisture in clothing systems worn by wildland firefighters may increase or decrease heat transfer, depending on its source and location in the clothing system, location on the body, timing of application and degree of sorption. In this experiment, 4 outerwear/underwear combinations were exposed to 1 of 5 different conditions varying on amount and location of moisture. The fabric systems were then exposed to either a high-heat-flux flame exposure (83 kW/m(2)) or a low-heat-flux radiant exposure (10 kW/m(2)). Under high-heat-flux flame exposures, external moisture tended to decrease heat transfer through the fabric systems, while internal moisture tended to increase heat transfer. Under low-heat-flux radiant exposures, internal moisture decreased heat transfer through the fabric systems. The nature and extent of such differences was fabric dependent. Implications for test protocol development are discussed.