Ecopath with Ecosim
Ecopath with Ecosim (EwE) is a featured ecosystem modeling software. It comes with some inbuilt ecosystem projects which you can use to get started with this software.
It has three main modules which facilitate you to create and analyze different ecosystem models. Let’s checkout these components and their working in detail.
In this module, you have to provide basic description and parameters of your ecosystem model. To start with, you need to enter model parameters such as name, model year, model area, description, publication, ecosystem type, country, biodiversity index, etc. Next, you have to add functional groups i.e. a set of species, like seals, birds, sharks, demersal, flatfish, phytoplankton, corals, toothed whales, baleen whales, etc. You can categorize these groups as consumer, producer, or detritus. Now, you can add values for basic input (habitat area, biomass, production/biomass, consumption/biomass, ecotrophic efficiency, mortality, detritus import, etc.), diet composition, detritus rate, other production (immigration, emigration, etc.), fishery (fleets definition, landing, discard, non-market price, etc.), and tools (growth input, pedigree, traits).
After setting up the input values for your ecosystem model, save the model. As output, you get basic estimates for trophic level, habitat area, biomass, ecotrophic efficiency, etc. for each functional group. In addition, you also get values of key indices (net efficiency, omnivory index, flow to detritus, net migration), mortality rate (fishing, predation, net, etc. mortality rate), consumption, niche overlap (prey overlap, predator overlap, respiration, ect.), electivity, search rates, fishery (quantity, value), particle size distribution (growth estimates, size weight plot, etc.). It also displays flow diagram of your Ecopath model, related statistics, pre-balanced diagnostics, and network analysis (trophic level decomposition, mixed trophic impact, value chain, ecosystem network analysis, cycles and pathways, ascendency, etc.).
Ecosim, as the name suggests, is the time dynamic simulation module to explore and analyze ecosystem policies. In this module, first, you have to describe a scenario and specify run parameters including duration in years, base proportion of free nutrients, minimum foraging time, nutrients loading forcing function, etc. You can add a time series manually or by importing a TXT file. You can view and add group information like feeding time adjust rate, predator effect on feeding time, switching power parameter, etc. There is a Vulnerabilities option which provides an Estimate Vulnerabilities tool. Using it, you can estimate vulnerability of groups with respect to carrying capacity/biomass. Other input parameters include mediation, forcing function, functional responses, egg production, fishing effort, fishing mortality, price elasticity, fleet size dynamics. Now, let’s see the output features you get.
- Ecosystem Policy Analysis: You can run simulation for the created Ecosim model. It lets you set fishing rate and then generates time series of biomasses in a graph. You can also view the graph for a particular functional group. Other output tools are graph plot (various graphs including biomass, fishing mortality, consumption/biomass, etc.), Ecosim results, Ecosim all fits, Stock-Recruitment plot (multi-stanza groups only), suitability plot (elecitivity, functional response, suitability), and flow diagram.
This is a spatial and temporal dynamic module which lets you explore impact and placement of protected areas. Let’s see what are the inputs you need to design Ecospace models and the outputs you get afterward.
- Input: Firstly, you need to describe scenarios, model type, run time, effort calculations, etc. Now, you can edit basemaps, set number of habitats and marine protected regions, assign habitats, add dispersal rate, edit advection map, define Ecospace fishery, and add some other external data.
- Output: Run Ecospace and Ecospace results are two options in its output menu. Using the former one, you can run simulation of your Ecospace project and view graph and map for functional groups. While summarized results are displayed in results tab. It also provides an additional spatial optimization tool to basically evaluate optimum placement of marine protected areas.
Other beneficial features of this ecosystem software
- It provides some other useful tools called Ecotracer (predicts temporal changes in biomass flows among functional groups) and management procedures (to evaluate biomass mean, catch mean, etc.).
- If your model is not mass balanced or contains some other error, it reports errors in status tab present below its interface. So, you can correct these errors and build a credible ecosystem model.
- It lets you save various output graphs, results, summary, etc. in different formats, such as CSV, BMP image, etc. Also, it provides a Result Extractor tool which lets you export selective results to a CSV file.
- You can install some add-ons (like Ecotrophs) to enhance its functionality.
- It provides some preferences to customize, like color schemes, font, etc. by using Tools > Options. From there, you can manage plugins too, such as Ecological Indicator, Ecotroph, Shape Grid, etc.