John P. Bolte

Applications of geographical information systems (GIS) for spatial decision support in aquaculture

Geographical information systems (GIS) are becoming an increasingly integral component of natural resource management activities worldwide. However, despite some indication that these tools are receiving attention within the aquaculture community, their deployment for spatial decision support in this domain continues to be very slow. This situation is attributable to a number of constraints including a lack of appreciation of the technology, limited understanding of GIS principles and associated methodology, and inadequate organizational commitment to ensure continuity of these spatial decision support tools. This paper analyzes these constraints in depth, and includes reviews of basic GIS terminology, methodology, case studies in aquaculture and future trends. The section on GIS terminology addresses the two fundamental types of GIS (raster and vector), and discusses aspects related to the visualization of outcomes. With regard to GIS methodology, the argument is made for close involvement of end users, subject matter specialists and analysts in all projects. A user-driven framework, which involves seven phases, to support this process is presented together with details of the degree of involvement of each category of personnel, associated activities and analytical procedures. The section on case studies reviews in considerable detail four aquaculture applications which are demonstrative of the extent to which GIS can be deployed, indicate the range in complexity of analytical methods used, provide insight into issues associated with data procurement and handling, and demonstrate the diversity of GIS packages that are available. Finally, the section on the future of GIS examines the direction in which the technology is moving, emerging trends with regard to analytical methods, and challenges that need to be addressed if GIS is to realize its full potential as a spatial decision support tool for aquaculture.

Examining fire-prone forest landscapes as coupled human and natural systems

Fire-prone landscapes are not well studied as coupled human and natural systems (CHANS) and present many challenges for understanding and promoting adaptive behaviors and institutions. Here, we explore how heterogeneity, feedbacks, and external drivers in this type of natural hazard system can lead to complexity and can limit the development of more adaptive approaches to policy and management. Institutions and social networks can counter these limitations and promote adaptation. We also develop a conceptual model that includes a robust characterization of social subsystems for a fire-prone landscape in Oregon and describe how we are building an agent-based model to promote understanding of this social-ecological system. Our agent-based model, which incorporates existing ecological models of vegetation and fire and is based on empirical studies of landowner decision-making, will be used to explore alternative management and fire scenarios with land managers and various public entities. We expect that the development of CHANS frameworks and the application of a simulation model in a collaborative setting will facilitate the development of more effective policies and practices for fire-prone landscapes.

The ModCom modular simulation system

Simulation models of agro-ecological systems are typically written in a manner that precludes reusability of parts of the model without a significant amount of familiarity with and rewriting of existing code. Similarly, replacing a part of a model with a functionally equivalent part from another model is typically difficult. The objective of this study was to develop a method to enable the assembly of simulation models from previously and independently developed component models. Recent advances in software engineering have enabled the development of software applications from smaller parts (called components) on the basis of an abstract decomposition of the relevant domain (called a framework). Based on a requirements analysis of existing simulation models we developed the ModCom simulation framework. ModCom provides a set of interface specifications that describe components in a simulation. ModCom also provides implementations of the core simulation services. The framework interfaces use well-defined binary standards and allows developers to implement the interfaces using a broad range of computer languages. Using this framework, simulation models can be assembled by connecting component models in much the same way that Lego blocks are put together to assemble a house. ModCom thus allows modelers to create models and modeling tools that are easily exchanged (in binary form or source code) with colleagues across the hall or across the globe.

Policy Research Using Agent-Based Modeling to Assess Future Impacts of Urban Expansion into Farmlands and Forests

The expansion of urban land uses into farmlands and forests requires an assessment of future ecological impacts. Spatially explicit agent-based models can represent the changes in resilience and ecological services that result from different land-use policies. When modeling complex adaptive systems, both the methods used to interpret results and the standards of rigor used to judge adequacy are complicated and require additional research. Recent studies suggest that it would be appropriate to use these models as an extension of exploratory analysis. This type of analysis generates ensembles of alternate plausible representations of future system conditions. User expertise steers interactive, stepwise system exploration toward inductive reasoning about potential changes to the system. In this study, we develop understanding of the potential alternative futures for a social-ecological system by way of successive simulations that test variations in the types and numbers of policies. The model addresses the agricultural- urban interface and the preservation of ecosystem services. The landscape analyzed is at the junction of the McKenzie and Willamette Rivers adjacent to the cities of Eugene and Springfield in Lane County, Oregon. Our exploration of alternative future scenarios suggests that policies that constrain urban growth and create incentives for farming and forest enterprises to preserve and enhance habitat can protect ecosystem resilience and services.

AquaFarm: simulation and decision support for aquaculture facility design and management planning

Abstract Development and application of a software product for aquaculture facility design and management planning are described (AquaFarm, Oregon State University©). AquaFarm provides: (1) simulation of physical, chemical, and biological unit processes; (2) simulation of facility and fish culture management; (3) compilation of facility resource and enterprise budgets; and (4) a graphical user interface and data management capabilities. These analytical tools are combined into an interactive, decision support system for the simulation, analysis, and evaluation of alternative design and management strategies. The quantitative methods and models used in AquaFarm are primarily adapted from the aquaculture science and engineering literature and mechanistic in nature. In addition, new methods have been developed and empirically based simplifications implemented as required to construct a comprehensive, practically oriented, system level, aquaculture simulator. In the use of AquaFarm, aquaculture production facilities can be of any design and management intensity, for purposes of broodfish maturation, egg incubation, and/or growout of finfish or crustaceans in cage, single pass, serial reuse, water recirculation, or solar-algae pond systems. The user has total control over all facility and management specifications, including site climate and water supplies, components and configurations of fish culture systems, fish and facility management strategies, unit costs of budget items, and production species and objectives (target fish weights/states and numbers at given future dates). In addition, parameters of unit process models are accessible to the user, including species-specific parameters of fish performance models. Based on these given specifications, aquaculture facilities are simulated, resource requirements and enterprise budgets compiled, and operation and management schedules determined so that fish production objectives are achieved. When facility requirements or production objectives are found to be operationally or economically unacceptable, desired results are obtained through iterative design refinement. Facility performance is reported to the user as management schedules, summary reports, enterprise budgets, and tabular and graphical compilations of time-series data for unit process, fish, and water quality variables. Application of AquaFarm to various types of aquaculture systems is demonstrated. AquaFarm is applicable to a range of aquaculture interests, including education, development, and production.

IMPLICATIONS OF RIPARIAN MANAGEMENT STRATEGIES ON WOOD IN STREAMS OF THE PACIFIC NORTHWEST

Riparian forest management plans for numerous regions throughout the world must consider long-term supply of wood to streams. The simulation model OSU STREAMWOOD was used to evaluate the potential effects of riparian management scenarios on the standing stock of wood in a hypothetical stream in the Pacific Northwest, USA. OSU STREAMWOOD simulates riparian forest growth, tree entry (including breakage), and in-channel processes (log breakage, movement, and decomposition). Results of three simulation scenarios are reported. The first scenario assessed total wood volume in the channel from Douglas-fir plantations clearcut to the stream bank using three rotation periods (60, 90, and 120 yr). Without a forested riparian management zone, accumulation of wood in the channel was minimal and did not increase through time. In the second scenario, response of total wood volume to forested riparian management zones of widths between 6 m and 75 m was evaluated. Total wood volume associated with the 6 m wide nonharvest...

Anticipating floodplain trajectories: a comparison of two alternative futures approaches

Scenario-based investigations explore alternative future courses of action in a widening array of situations. Anticipating landscape patterns and the values behind them are recurring needs in such investigations. While it is accepted that how scenario assumptions are framed and who frames them matters, the sensitivity of resulting trajectories to contrasting scenario framing and modeling processes is rarely tested. Using comparable scenarios we contrast landscape change trajectories produced from two distinct approaches to modeling scenario assumptions: the first uses lay citizen groups and deterministic land allocation modeling, the second uses experts from biophysical and social sciences and agent-based modeling. Scenarios are defined and mapped for the year 2050 in western Oregon’s Willamette River Basin along a gradient of conservation oriented to development-oriented assumptions using first citizen-based and then expert-based approaches. The landscape variability and trajectories for the citizen-based Conservation 2050 and Development 2050 scenarios are then characterized and compared with those of the expert-based Conservation 2050 and Development 2050 scenarios. Results distinguish areas where trajectories always vary regardless of approach or scenario from those that never vary. Policy influence on trajectory is illustrated using agent-based model results where land conversion serves purposes of wealth production and ecosystem function. Results depict areas with strong coupling between policy and trajectory as those places experiencing the same pattern of change over time regardless of scenario. Results also indicate that the greater the variability of a given scenario’s trajectories, the more successful the scenario is at avoiding scarcity of wealth and ecosystem function.

EVALUATING THE IMPACT OF POLICY OPTIONS ON AGRICULTURAL LANDSCAPES: AN ALTERNATIVE-FUTURES APPROACH

Alternative-futures analysis was used to analyze different scenarios of future growth patterns and attendant resource allocations on the agricultural system of Oregons Willamette River Basin. A stakeholder group formulated three policy alternatives: a continuation of current trends, an increased reliance on market forces to determine land use, and an increased emphasis on environmental restoration programs. To model the alternative scenarios first required the development of a spatial representation of the current agricultural system. Next, rules and constraints based on the three policy scenarios were formulated. Then a spatially explicit, multi-attribute, decision-making model was used to model changes in agricultural land cover and land use. This procedure generated three future landscapes, each depicting an alternative state of the agricultural system in the year 2050. Finally, the agronomic and environmental condition of each agricultural system was evaluated by using landscape metrics and screening models. The results show that the type and amount of farmland conversion were the scenario elements that most distinguished the future agricultural landscapes. By continuing current land use policies, nearly all of the existing farmland was conserved for future agricultural use, while both the market-driven and environmental restoration scenarios converted 15% or more of the agricultural land to other uses. The use of farmland for vegetation restoration activities was particularly successful in improving riparian habitat, while habitat quality over the region showed widespread improvement. The patterns of crop selection in each future followed general trends, but with variations among scenarios as crop selection decisions adapted to changing field and basin conditions.

A water budget model for pond aquaculture

A water budget simulation model that can be used for forecasting water requirements for aquaculture ponds has been developed. Water sources considered in the model include regulated inflow, precipitation and runoff, whereas water losses include evaporation, seepage, effluent discharge, and overflow. The model has been validated for ponds located at the Asian Institute of Technology (AIT), Thailand and at El Carao, Honduras which are, respectively, located in the humid and dry tropics. Simulation results indicate that precipitation accounted for 69.8% of the total water gains for AIT and 43.2% for El Carao. Regulated inflow provided 27% of the gains for AIT and 52.8% for El Carao. Runoff gains were minimal at both locations due to small watershed areas. Evaporation accounted for 54.9 and 40.1% of the overall water loss predicted for the AIT and El Carao locations, with seepage accounting for the remaining loss. Predicted water requirements at AIT over a 5-month period exceeded actual amounts by 14.9%, apparently because seepage loss was over-estimated. For El Carao, however, predicted water requirements were only 78.2% of the amount actually added, apparently due to poor estimates of evaporative water loss which averaged 0.32 cm day−1 compared to pan evaporative measurements of 0.43 cm day−1. In contrast, the predicted evaporative water loss for the AIT pond (0.47 cm day−1) closely matched pan evaporation measurements (0.45 cm day−1). The availability of relative humidity and cloud cover data for AIT explain the higher accuracy in evaporative water loss estimates, and therefore water requirements, compared to El Carao. If comprehensive weather datasets are available, the water budget model developed herein is a useful tool for estimating pond water requirements at individual facilities located in different geographical regions.

Development of decision support tools for aquaculture: the POND experience

Abstract Decision support systems (DSS) are potentially valuable tools for assessing the economic and ecological impacts of alternative decisions on aquaculture production. In this paper, we discuss the philosophy of design, functional modules and application areas of POND, a decision tool that has been developed to allow analysis of pond aquaculture facilities by the use of a combination of simulation models and enterprise budgeting. We focus less on the details of POND’s internal models, and more on the experiences we have gained from going through the process of the designing, developing and using the POND software. POND was designed and implemented using object-oriented programming principles. The software makes use of a simulation framework to provide much of the generic simulation, data handling, time flow synchronization and communication features necessary for complex model-based DSSs. Additionally, an architecture suitable for representing and manipulating pond aquaculture facilities was developed in order to meet the design specifications of POND. This architecture includes a series of mini-databases, a number of knowledge-based components (‘experts’), models of the pond ecosystem, and various decision support features (e.g. assembling alternate management scenarios, economic analysis, and data visualization). A typical POND simulation consists of assembling a number of appropriate objects or entities (e.g. multiple ponds and fish lots), their management settings together with appropriate experts (e.g. an aquaculture engineer, an aquatic biologist, an economist, etc.), and projecting changes in the facility over time. Our experience with the development of POND and other simulation-based tools indicates that the object-based approach provides a robust foundation for developing tools which allow code reusability, facilitate maintenance of complex software, and enable partition of program development among multiple programmers. Experience gained with POND users suggests that there are largely two groups of aquaculture personnel interested in such applications, namely commercial growers and educators. These two groups have substantially different interests and needs. Consequently, a single tool such as POND may not optimally meet the requirements of both groups. Recent development work on POND, and the need to involve users in the design process of such tools are discussed.