Opuntia in México: Identifying Priority Areas for Conserving Biodiversity in a Multi-Use Landscape

BACKGROUND: México is one of the world's centers of species diversity (richness) for Opuntia cacti. Yet, in spite of their economic and ecological importance, Opuntia species remain poorly studied and protected in México. Many of the species are sparsely but widely distributed across the landscape and are subject to a variety of human uses, so devising implementable conservation plans for them presents formidable difficulties. Multi-criteria analysis can be used to design a spatially coherent conservation area network while permitting sustainable human usage. METHODS AND FINDINGS: Species distribution models were created for 60 Opuntia species using MaxEnt. Targets of representation within conservation area networks were assigned at 100% for the geographically rarest species and 10% for the most common ones. Three different conservation plans were developed to represent the species within these networks using total area, shape, and connectivity as relevant criteria. Multi-criteria analysis and a metaheuristic adaptive tabu search algorithm were used to search for optimal solutions. The plans were built on the existing protected areas of México and prioritized additional areas for management for the persistence of Opuntia species. All plans required around one-third of México's total area to be prioritized for attention for Opuntia conservation, underscoring the implausibility of Opuntia conservation through traditional land reservation. Tabu search turned out to be both computationally tractable and easily implementable for search problems of this kind. CONCLUSIONS: Opuntia conservation in México require the management of large areas of land for multiple uses. The multi-criteria analyses identified priority areas and organized them in large contiguous blocks that can be effectively managed. A high level of connectivity was established among the prioritized areas resulting in the enhancement of possible modes of plant dispersal as well as only a small number of blocks that would be recommended for conservation management

Ownership structure and accountability: the case of the privatization of the Spanish tobacco monopoly, 1887-96

This paper analyses the case of the privatization of the Spanish tobacco monopoly, focusing on the period between 1887 and 1896, which corresponds to the first leasing contract between the state and the Spanish Tobacco Company and it is concerned with two different issues. First, it deals with the effects of privatization on accountability.The main question examined is whether public and private ownership entail different approaches to the way in which managers are accountable to owners, and the impact this issue had on corporate reporting. Second, it is concerned with exploring the determinants of accounting disclosure. Here, the basic issue is to understand the factors shaping changes in corporate reporting during the period of study.Accounting History, Corporate Reporting, Privatization, Tobacco Monopoly, Spain,