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To reduce global biodiversity loss, there is an urgent need to determine the most efficient allocation of conservation resources. Recently, there has been a growing trend for many governments to supplement public ownership and management of reserves with incentive programs for conservation on private land. At the same time, policies to promote conservation on private land are rarely evaluated in terms of their ecological consequences. This raises important questions, such as the extent to which private land conservation can improve conservation outcomes, and how it should be mixed with more traditional public land conservation. We address these questions, using a general framework for modelling environmental policies and a case study examining the conservation of endangered native grasslands to the west of Melbourne, Australia. Specifically, we examine three policies that involve: i) spending all resources on creating public conservation areas; ii) spending all resources on an ongoing incentive program where private landholders are paid to manage vegetation on their property with 5-year contracts; and iii) splitting resources between these two approaches. The performance of each strategy is quantified with a vegetation condition change model that predicts future changes in grassland quality. Of the policies tested, no one policy was always best and policy performance depended on the objectives of those enacting the policy. This work demonstrates a general method for evaluating environmental policies and highlights the utility of a model which combines ecological and socioeconomic processes.Comment: 20 pages, 5 figure

“Echini are a particularly good group in which to study questions of variation, because here variations can usually be expressed in very definite terms of numerical or other equally positive character.” On this account, and because, in spite of much description, the variants liable to occur in sea urchins have not yet been exhausted, the three specimens described below are recorded. Each of these exhibits a pronounced abnormality in the major symmetries. Two of them resemble another abnormal echinoid in the same collections, already discussed in Proc. Zool. Soc., in lacking part of a definite ambulacrum; but the means by which the tests have accommodated themselves to changed conditions of growth differ markedly in each of the three cases. The third specimen exhibits, in place of the normal five-radiate arrangement, almost perfect hexamery—a type of abnormality very different from that of the first two specimens. For in these the distortion is due to incomplete development caused, by interference with the processes of growth, while there the hexamery is a fundamental change in symmetry, is congenital in origin, and probably represents the type of variation known as duplication of parts.

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