Abstract:
There are a number of specialized ecological models used at Texas Tech University, but the EDYS model (Ecological Dynamics Simulation) is the only general ecosystem model. In this presentation, I will go over some of the history of EDYS, hoping to explain the logic and reasoning behind many of our design decisions. Our primary objective was to build a model that could be used in a variety of ecosystem types, and across a range of spatial and temporal scales, by restoration ecologists, land managers, and field biologists, to evaluate the impacts of a wide variety of natural and anthropogenic stressors. The realities these end-users face has driven some of the most fundamental design decisions, particularly with regards to computing resources. Next, I will highlight the blind validation studies we’ve conducted to establish the validity of our approach and implementation. And last, I would like to describe several of the many projects we’ve participated in, illustrating the broad array of ecological issues that EDYS has been used to address.
Bio:
Cade Coldren is an Assistant Professor in the Natural Resources Management Department at Texas Tech University. He completed his PhD in Wildlife and Fisheries Sciences at Texas A&M University in 1998, where he also earned a BS in Electrical Engineering in 1982 and MS in Wildlife and Fisheries Sciences in 1992. He is one of the co-developers of the Ecological Dynamics Simulation (EDYS) model, which has been applied nationally and internationally to address ecosystem impacts by a variety of stressors, both natural and anthropogenic. He also has a research interest in avian ecology and management, particularly in relation to climate change, invasive species, and urban ecosystems.
Summary:
EDYS
Ecosystems: Grasslands, Savanna, forests
Users: land managers, field biologists, restoration ecologists, environmental planning and compliance teams
Platforms: commodity Windows PCs
Goal: common model architecture that works for many ecosystem types
Types of models
Statistical / Empirical
State transition
Mechanistic
Mechanistic models are most transferable
Focus areas:
Plant dynamics: Plant dormancy, germination, water uptake, nutrients…
Soil hydrology: rainfall, interception, evaporation, recharge runoff
Environment: Spatial heterogeneity, erosion/deposition, herbivory, groundwater, competition, contaminants, fire, animals, management and stressors
Literature contains qualitative descriptions of these processes (major dynamics steps and forcing functions but no concrete equations)
EDYS: same core algorithms, only changing inputs
Time step: daily (determined by plant dynamics: grow during the day)
Hourly when linked to a bay circulation model to capture tidal/salinity dynamics
Length of run 1-250 years
Driven by detailed maps of the topography and ecology: elevation, soil, plant communities (unique combination of plants, soils, elevation, slope, aspect)
Plant communities
Focus on dominant species and ecologically important species, rare species, important for human society
As the number increases, realism increases but also complexity of interpreting the results
Plant parameters: (37 matrices) growth, roots, phenology, germination, water use, nutrient requirements/use, dormancy, light competition/shading, tolerance to salinity/flooding, fuel load/fire, herbivory
2D spatial model, variable spatial resolution