A salmonid individual‐based model as a proposed decision support tool for management of a large regulated river

Abstract

Citation: Dudley, P. N. 2018. A salmonid individual-based model as a proposed decision support tool for management of a large regulated river. Ecosphere 9(1):e02074. 10. 1002/ecs2.2074 Abstract. Large regulated rivers often require fisheries and water managers to make management decisions involving resident fish population dynamics that have many ecological drivers. Because of the large scale of the system and often competing interests and demands for water, there is a critical need for decision support tools (DSTs) that allow examination of alternative management scenarios while considering key ecological interactions. Spatially explicit individual-based models (IBMs) can serve as effective DSTs by providing information on fish population dynamics while accounting for, and providing extensive, spatially explicit information on, the numerous ecological drivers. Spatially explicit IBMs are often difficult to implement owing to the numerous and often complex inputs the models require. Here, I demonstrate how a suite of free, graphical user interface equipped programs, along with three custombuilt and publicly available plugins, can streamline the modeling process and serve as a IBM-based DST for fisheries management on large regulated rivers. The main program is a spatially explicit IBM of juvenile salmonid dynamics, inSALMO, with two other programs that generate the key input data in the required spatially explicit formats. I then use this proposed DST to simulate a Chinook salmon population on a portion of California's Sacramento River to determine whether an IBM-based DST is appropriate to evaluate management impacts on a large regulated river. The Sacramento is a large river of major concern in California and is representative of many rivers in the United States and worldwide in that it is dammed, has a resident fish population, and is heavily used for water supply. The proposed DTS results compare favorably with the predictive power of a general additive model, while providing a much fuller and richer data set that could significantly aid and inform management decisions.

Individual‐based simulations suggest mixed impacts of warmer temperatures and a nonnative predator on Chinook salmon

“…Modeling interactive ways that climate change can affect native coldwater species—not simply warmer temperatures, but also interactions with warmwater nonnative species—can provide more information for managers faced with producing effective conservation plans (Beechie et al 2012, Crozier and Hutchings 2014, Lawrence et al 2014). Our model demonstrates how a multispecies (Stillman et al 2015) and spatially explicit individual‐based model could be a useful decision support tool for fisheries management (Dudley 2018) at a scale that helps bridge the gap between research and conservation (Fausch et al 2002). Our model could be applied and calibrated to other watersheds with rich fish and temperature datasets, and it could be expanded to explore interactions among additional native and nonnative species in a changing climate.…”

From meta-system theory to the sustainable management of rivers in the Anthropocene

“…However, empirical data on metapopulations are not always available for managers, and monitoring efforts and open data sharing should be promoted. Such information could be integrated in individual-based models and thereby contribute to identify critical thresholds (Dudley 2018).…”

“…There are already some prioritization tools available to integrate spatial dynamics into conservation planning (e.g. Hermoso et al 2013;2018), and most policies and related guidance documents promote adaptive management incorporating cross-ecosystem processes and scale-dependency. However, the implementation of these tools and principles is still rare (Acreman et al 2020).…”

Predicting impacts of chemicals from organisms to ecosystem service delivery: A case study of endocrine disruptor effects on trout

“…We chose this model because it can represent key mechanisms through which EE2 and other stressors affect individual trout and how these individual-level effects impact population-level phenomena of interest. The model is wellestablished: the inSTREAM family of salmonid IBMs has been used in approximately 15 published studies since 1999, including a recent evaluation of its usefulness for complex management decision support (Dudley, 2018). We briefly describe the model here, focusing on parts especially relevant to this case study.…”