Expanding human population and economic growth have lead to large-scale conversion of natural habitat to human-dominated landscapes with consequent large-scale declines in biodiversity. Conserving biodiversity, while at the same time meeting expanding human needs, is an issue of utmost importance. In this paper we develop a spatially explicit landscape-level model for analyzing the biological and economic consequences of alternative land-use patterns. The spatially-explicit biological model incorporates habitat preferences, area requirements and dispersal ability between habitat patches for terrestrial vertebrate species to predict the likely number of species that will be sustained on the landscape. The spatially explicit economic model incorporates site characteristics and location to predict economic returns in a variety of potential land uses. We use the model to search for efficient land-use patterns that maximize biodiversity conservation objectives for a given level of economic returns, and vice-versa. We apply the model to the Willamette Basin, Oregon, USA. By thinking carefully about the arrangement of activities, we find land-use patterns that sustain high biodiversity and economic returns. Compared to the current land-use pattern, we show that both biodiversity conservation and the value of economic activity could be increased substantially.

eluding summaries of 28 invited lectures. The complete texts of the invited lectures will appear in a hard-bound volume which is in preparation. The papers are divided into seven categories: General Theory, Metals and Composites, Geological Materials, Discontinuous Media, Concrete, Granular Materials and Aggregates, and Implementation and Evaluation. The objective of the conference was to stimulate interaction between researchers concerned with the theoretical and experimental aspects of developing constitutive models of deformable solids and those concerned with the implementation of constitutive laws in engineering analysis and design. Many individuals who are active in the field of the conference contributed articles and, consequently, the volume provides a reasonably complete picture of the current state of development of models for describing the mechanical behavior of solids. Of course, the volume would be more valuable if it contained complete texts of the overview lectures as well as the contributed articles.

In most species, sport hunting of male trophy animals can only reduce overall population size when the rate of removal of males is so high that females can no longer be impregnated. However, where males provide extensive paternal care, the removal of even a few individuals could harm the population as a whole. In species such as lions, excessive trophy hunting could theoretically cause male replacements (and associated infanticide) to become sufficiently common to prevent cubs reaching adulthood. Here we simulate the population consequences of lion trophy hunting using a spatially explicit, individual-based, stochastic model parameterized with 40 years of demographic data from northern Tanzania. Although our simulations confirm that infanticide increases the risk of population extinction, trophy hunting could be sustained simply by hunting males above a minimum age threshold, and this strategy maximizes both the quantity and the quality of the long-term kill. We present a simple non-invasive technique for estimating lion age in populations lacking long-term records, and suggest that quotas would be unnecessary in any male-only trophy species where age determination could be reliably implemented.

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Habitat loss and fragmentation are major threats to biodiversity. Establishing formal protected areas is one means of conserving habitat, but socio-economic and political constraints limit the amount of land in such status. Addressing conservation issues on lands outside of formal protected areas is also necessary. In this paper we develop a spatially explicit model for analyzing the consequences of alternative land-use patterns on the persistence of various species and on market-oriented economic returns. The biological model uses habitat preferences, habitat area requirements, and dispersal ability for each species to predict the probability of persistence of that species given a land-use pattern. The economic model uses characteristics of the land unit and location to predict the value of commodity production given a land-use pattern. We use the combined biological and economic model to search for efficient land-use patterns in which the conservation outcome cannot be improved without lowering the value of commodity production. We illustrate our methods with an example that includes three alternative land uses, managed forestry, agriculture, and biological reserve (protected area), for a modeled landscape whose physical, biological, and economic characteristics are based on conditions found in the Willamette Basin in Oregon (USA). We find that a large fraction of conservation objectives can be achieved at little cost to the economic bottom line with thoughtful land-use planning. The degree of conflict between conservation and economic returns appears much less using our joint biological and economic modeling approach than using a reserve-site selection approach, which assumes that species survive only inside of reserves and economic activity occurs only outside of reserves.