Macroinvertebrates

1. Macroinvertebrates Thomas Hardy

3. Background • little was known regarding modeling approaches that might be applicable to address key HCP issues including: • 1) fountain darter (Etheostomafonticola) food source (aquatic macroinvertebrates) dynamics and response, and • 2) Comal Springs riffle beetle (Heterelmiscomalensis) response to extreme low flow conditions.

4. The specific Task 1 charge • “to gather and review pertinent scientific literature with respect to two issues: • (1) identifying a modeling approach for predicting aquatic macroinvertebrate responses to changing physical, chemical, and biotic (i.e., aquatic vegetation dynamics); and • (2) existing modeling approaches that may have potential for modification to address the EAHCP specific applications regarding the Comal Springs riffle beetle response/dynamic, even if the literature does not specifically address the Comal Springs riffle beetle.” • reviewed approximately 200 journal articles and gray literature reports

5. the Comal Springs riffle beetle • Basically nothing found

6. The short answer • Comal springs riffle beetle • Bayesian belief network • Lack of quantitative data on life history limits • Can use expert knowledge as an initial placeholder using influence diagrams already developed • Can be quickly updated as applied research improves knowledge

8. macroinvertebrates • This review of potential modeling approaches was undertaken in light of: • known data availability on the Comal and San Marcos river systems • water quantity and quality data, and • the long term biological monitoring data

9. Potential modeling approaches • the state of knowledge about the system (components and their interactions) • consider the available data necessary to parameterize the model during calibration and subsequent validation efforts. • consideration was given to the time constraints required for modeling results to support the HCP adaptive management schedule where decisions on ‘Phase I’ dictate that model development and application occur over the next two to three year period. • This constrains the time necessary to conduct extensive applied research or field-based monitoring of required data sets to parameterize, calibrate, and validate the model(s), and underscores the need to maximize the use of existing data and models where possible.

10. Some potential approaches considered • Fuzzy Logic Models • Bayesian Belief Networks • Artificial neural networks • Individual based models • Mechanistic based models

11. Schuwirth and Reichert (2013) • combines concepts of • theoretical food web modeling, • the metabolic theory of ecology, • ecological stoichiometry • use of functional trait databases to predict the coexistence of invertebrate taxa in streams • mechanistic model that describes growth, death, and respiration of different taxa dependent on various environmental influence factors to estimate survival or extinction • Parameter and input uncertainty are propagated to model results • tested using macroinvertebrate monitoring data from a catchment of the Swiss Plateau without fitting model parameters, and was able to represent key patterns of the coexistence structure of invertebrates at sites varying in external conditions (litter input, shading, and water quality)

12. Gertseva et al. (2004) • Incorporates theoretical and experimental aspects • The theoretical portion includes the development of a simulation model of macroinvertebrate community dynamics using STELLA software • The experimental portion focused on the validation of the model by comparing its simulations with observations from Holly Springs Creek in South Carolina, USA • constructed based on functional feeding groups comprised of: shredders, scrapers, collectors and predators. • Each block is comprised of three modules: • the module of the functional feeding group, • the module of the abiotic factors affecting functional feeding group and • the module of the biotic interactions among organisms within the community

18. Texas wild rice • Above and below ground biomass as a function of par reductions • 15 minute turbidity readings at 6 locations longitudinally • Hourly recreation counts at three rive segments • spatial and temporal patterns in suspended solids, water turbidity/light attenuation, sedimentation, and periphyton growth on TWR in situ • Above and below ground biomass as function of water velocity, light and turbidity in situ at 4 locations longitudinally • spatial and temporal patterns in light availability and pCO2 may affect the abundance and distribution of native macrophytes, particularly Texas wild rice (Zizaniatexana) in the upper portion of the San Marcos River

19. Among the grids, 95% tiller growth and plant expansion was observed with growth observed in as little as a month. TWR expansion was generally observed laterally to an existing patch or on the downstream portion of the patch among all ranges of depths and current velocities measured. No growth was observed at the upstream side of a TWR patch.