Crocodile farms and management of saltwater crocodiles in Northern Territory: Results of a survey of NT crocodile farmers plus analysis of secondary information

After outlining some relevant background information about the NT crocodile farming industry and explaining the purpose of our survey of NT crocodile farmers conducted in the first half of 2005, this paper reports the results of the survey. The information received from the survey is supplemented by secondary data and by information from secondary sources. This report covers the location of respondents; the size of crocodile farms; farmers’ stated knowledge of and attitudes towards the NT Crocodile Management Plan; the involvement of farms in the harvesting of crocodile eggs and the costs involved; views of crocodile farmers about whether the NT Crocodile Management Plan encourages landholders to conserve crocodiles and their perceptions of the benefits to landholders; predicted production trends and trends in the number of farms operating in NT; economic characteristics of crocodile farms producing in NT including the economic advantages and disadvantages of crocodile farming in NT. Concluding comments provide, amongst other things, an overview of the structure of the crocodile farming industry in the NT gleaned from a consideration of data available from the NT Government’s Department of Business, Industry and Resource Development.

Linking policies for biodiversity conservation with advances in behavioural economics

Global biodiversity loss and its consequences for human welfare and sustainable development have become major concerns. Economists have, therefore, given increasing attention to the policy issues involved in the management of genetic resources. To do so, they often apply empirical methods developed in behavioral and experimental economics to estimate economic values placed on genetic resources. This trend away from almost exclusive dependence on axiomatic methods is welcomed. However, major valuation methods used in behavioral economics raise new scientific challenges. Possibly the most important of these include deficiencies in the knowledge of the public (and researchers) about genetic resources, implications for the formation of values of supplying information to focal individuals, and limits to rationality. These issues are explored for stated-preference techniques of valuation (e.g., contingent valuation) as well as revealed preference techniques, especially the travel cost method. They are illustrated by Australian and Asian examples. Taking into account behavioral and psychological models and empirical evidence, particular attention is given to how elicitation of preferences, and supply of information to individuals, influences their preferences about biodiversity. Policy consequences are outlined.

Dynamic processes in the contingent valuation of an endangered mammal species

Reports experimental results involving 204 members of the public who were asked their willingness to pay for the conservation of the mahogany glider Petaurus gracilis on three occasions: prior to information being provided to them about the glider and other wildlife species; after such information was provided, and after participants had an opportunity to see live specimens of this endangered species. Variations in the mean willingness to pay are analysed. Concerns arise about whether information provision and experience reveal ‘true’ contingent valuations of public goods and about the choice of the relevant contingent valuation measure.

The effects of information request ambiguity and construct incongruence on query development

This paper examines the effects of information request ambiguity and construct incongruence on end user's ability to develop SQL queries with an interactive relational database query language. In this experiment, ambiguity in information requests adversely affected accuracy and efficiency. Incongruities among the information request, the query syntax, and the data representation adversely affected accuracy, efficiency, and confidence. The results for ambiguity suggest that organizations might elicit better query development if end users were sensitized to the nature of ambiguities that could arise in their business contexts. End users could translate natural language queries into pseudo-SQL that could be examined for precision before the queries were developed. The results for incongruence suggest that better query development might ensue if semantic distances could be reduced by giving users data representations and database views that maximize construct congruence for the kinds of queries in typical domains. (C) 2001 Elsevier Science B.V. All rights reserved.

The effect of resource aggregation at different scales: Optimal foraging behavior of Cotesia rubecula

Resources can be aggregated both within and between patches. In this article, we examine how aggregation at these different scales influences the behavior and performance of foragers. We developed an optimal foraging model of the foraging behavior of the parasitoid wasp Cotesia rubecula parasitizing the larvae of the cabbage butterfly Pieris rapae. The optimal behavior was found using stochastic dynamic programming. The most interesting and novel result is that the effect of resource aggregation within and between patches depends on the degree of aggregation both within and between patches as well as on the local host density in the occupied patch, but lifetime reproductive success depends only on aggregation within patches. Our findings have profound implications for the way in which we measure heterogeneity at different scales and model the response of organisms to spatial heterogeneity.