01946nas a2200157   4500008003900000245011100039210006900150300001200219490000600231520143500237100001701672700001301689700001401702700001501716856005701731       2013                          d00aEcosystem modelling for ecosystem-based management of bivalve aquaculture sites in data‑poor environment0 aEcosystem modelling for ecosystembased management of bivalve aqu  a117-1330 v43 aAlthough models of carrying capacity have been around for some time, their use in aquaculture management has been limited. This is partially due to the cost involved in generating and testing the models. However, the use of more generic and flexible models could facilitate the implementation of modelling in management. We have built a generic core for coupling biogeochemical and hydrodynamic models using Simile (www.simulistics.com), a visual simulation environment software that is well-suited to accommodate fully spatial models. Specifically, Simile integrates PEST (model-independent parameter estimation, Watermark Numerical Computing, www.pesthomepage.org), an optimization tool that uses the Gauss-Marquardt-Levenberg algorithm and can be used to estimate the value of a parameter, or set of parameters, in order to minimize the discrepancies between the model results and a dataset chosen by the user. The other critical aspect of modelling exercises is the large amount of data necessary to set up, tune and groundtruth the ecosystem model. However, ecoinformatics and improvements in remote sensing procedures have facilitated acquisition of these datasets, even in data-poor environments. In this paper we describe the required datasets and stages of model development necessary to build a biogeochemical model that can be used as a decision-making tool for bivalve aquaculture management in data-poor environments.1 aFilgueira, R1 aGrant, J1 aStuart, R1 aBrown, M S  uhttp://www.int-res.com/abstracts/aei/v4/n2/p117-133/01479nas a2200121   4500008003900000245007700039210006900116300000700185490000700192520102900199100002201228856010701250       2008                          d00aA spatiotemporal model of shifting cultivation and forest cover dynamics0 aspatiotemporal model of shifting cultivation and forest cover dy  a280 v133 a<p>Sustainable use of humid forest resources as a source of fertile land for cultivation requires long periods of fallow and the ability to move the zone of active cultivation from one location to another over time. At the individual field level, shifting cultivation is essentially a resource extraction problem akin to a pulse fishery &ndash; a short period of intensive use of the stock of soil fertility followed by a long idle period permitting regeneration. This paper describes a spatiotemporal model of resource extraction adapted to the use of forest resources by shifting cultivators. Theoretically grounded in the spatial and household modelling literature, it is a structural simulation model of household decision-making, and includes a demonstration of the conceptwith a limited data set from southern Cameroon. Use of a stated preference approach to modelling decision-making identifies individual preferences and spatial path-dependency as important sources of shortened fallows and resource degradation.</p>1 aBrown, Douglas, R  u//www.simulistics.com/publications/spatiotemporal-model-shifting-cultivation-and-forest-cover-dynamics02591nas a2200205   4500008003900000245013100039210006900170260002200239300001200261490000700273520181500280653002402095653002002119653001602139653002502155653002902180653002702209100002202236856012702258       2006                          d00aPersonal preferences and intensification of land use: their impact on southern Cameroonian slash-and-burn agroforestry systems0 aPersonal preferences and intensification of land use their impac  bSpringerc03/2006  a53–670 v683 a<p>Where long forest-fallows are no longer practiced, productivity declines in the absence of input substitution, as does the ability of subsistence farmers to earn an adequate livelihood from shifting cultivation. Land availability, population density and productivity-related factors such as soil fertility and labour requirements are not the only factors that affect fallow length and land use intensification in shifting cultivation agroforestry systems. Households surveyed indicated that various other decision criteria (e.g., proximity to other fields and the protection of land use rights) are important in land use decisions. Even though one quarter of households reported insufficient land resources to maintain soil fertility, few actually indicated that their choices were constrained by land availability. In fact, many cleared much younger fallows than strictly necessary based on the age of fallows available in their land holdings &ndash; even those with fallows of sufficient age to maintain long-term productivity. This paper outlines an approach to quantify information about the household preferences that influence land use decisions, discusses the implications of these decision criteria for land use intensification and uses them to model household decision-making in a way that effectively simulates the spatial and dynamic mosaic of land use characteristic of shifting cultivation. Not only are non-productivity related decision criteria important in land use decisions in general; they also have a significant impact on land use intensification. In fact, the research described here demonstrates that both household-specific preferences and household-specific initial conditions can lead to intensification of land use apart from that arising due to increasing population density.</p>10aHousehold modelling10aIntensification10aPreferences10aShifting cultivation10aSpatiotemporal modelling10aSustainable forest use1 aBrown, Douglas, R  u//www.simulistics.com/publications/personal-preferences-and-intensification-land-use-their-impact-southern-cameroonian-sla