Study Title: Computer Simulation Modeling of Intermediate Trophic Levels for Across Trophic Level Systems Simulation of the Everglades/Big Cypress Region
Study Start Date: 1997 Study End Date: 12/31/07
Web Sites: ATLSS.ORG
Location: The Greater Everglades ecosystem
Funding Source: Critical Ecosystem Studies Initiative
Principal Investigator: Michael S. Gaines, Department of Biology, University of Miami, Coral Gables, FL 33124 Phone: 305-284-3974 e-mail: m.gaines@miami.edu
Study Personnel: Donald L. DeAngelis, Phone: 305-284-1690 e-mail: ddeangelis@umiami.ir.miami.edu
Other Supporting Organizations: USGS/BRD, NPS, ACE, EPA
Associated Projects: Component of ATLSS Program

Overview & Objectives: This project has had the goal of developing models for key components of the Everglades landscape as part of the overall Across Trophic Level System Simulation. Past research has developed the basic model for freshwater fish biomass and a model of energy flow in the reptile and amphibian community. Current work has involved modeling and empirical studies on the American crocodile, the snail kite, small mammals, and the oak toad. The objectives have been to understand the effects of hydrologic conditions on each of these taxa.

Status: Additional CESI money has been added to fund the project until 12/31/2005

Recent Products:
Snail kite modeling: Version 1 of the snail kite model has been completed. It has been used to evaluate the effects of the different Restudy and ModWater scenarios on the snail kite. The model has been used to demonstrate that decreases in area available for foraging can have a major impact on nesting success.

Crocodile modeling and empirical work: Paper is in press on the crocodile individual-based model.

Small mammal field work: This past work has given us insight into the effects of interactions with biotic and abiotic factors. Our previous work has given us a better understanding of the role of hydroperiods on the patch dynamics of the two most prominent small mammal species, the silver rice rat (Oryzomys palustris) and the cotton rat (Sigmodon hispidus)

Some recent publications are:

Dreitz, V. J., W. M. Kitchens, and D. L. DeAngelis. 2004. The effects of natal departure and water level on survival of juvenile snail kites in Florida. The Auk 121:894-903

Mooij, W. M., and D. L. DeAngelis. 2003. Uncertainty in spatially explicit animal dispersal models. Ecological Applications 13:794-805.

DeAngelis, D. L. and W.M. Mooij. 2003. In praise of mechanistically-rich models. Pp. 63-82, in C. D. Canham, J. J. Cole, and W. K. Lauenroth (eds.) Models in Ecosystem Science. Princeton University Press, Princeton, New Jersey.

Mooij, W. M., R. E. Bennetts, W. M. Kitchens, and D. L. DeAngelis. 2002. Exploring the effect of drought extent and interval on the Florida snail kite: Interplay between spatial and temporal scales. Ecological Modelling 149 (1-2):25-39.

Richards, P. M. 2004. Evaluating the relative effects of life history stages in the conservation of the American crocodile (Crocodylus americanus) in Florida. Florida Scientist 66(4):273-286.

Planned Products: Work is continuing in the following directions:

• The snail kite model, EVERKITE (Version 2.0), will be used in CERP evaluations. It has been developed and delivered to agency users.
• Oak toad field work: The proposed study intends to further develop a Habitat Suitability Index (HIS) for the oak toad. This HIS model was first developed by George Dalrymple to correlate Bufo quercicus abundance with habitat type and hydrological condition within the marl prairies and pinelands of Everglades National Park (ENP). We will further calibrate this model in order to detect the effects of hydrology in Everglades National Park on B. quercicus, and how changes in the hydrology and habitat due to the large-scale Everglades restoration efforts (CERP) will affect the Oak Toad.
• We are also proposing to develop and test habitat suitability indices for one or more small mammals that are native to ENP.

Specific Relevance to Information Needs Identified in DOI's Science Plan in Support of Ecosystem Restoration, Preservation, and Protection in South Florida (DOI's Everglades Science Plan) [See Plan on SOFIA's Web site: http://sofia.usgs.gov/publications/reports/doi-science-plan/]:
Snail kite and fish landscape models were used in C&SF Restudy assessments (p. 96), in ModWaters Project design, and will be used in new CERP evaluations. Wading bird, snail kite, and American crocodile models are critical for implementing the Multi-Species Recovery Plan Wading bird, snail kite, American alligator, and American crocodile are all Specific Performance Measures (p. 92).

Key Findings:

1. Working version of snail kite model, EVERKITE
2. Publication of crocodile model
3. Information on effects of hydrology on small mammal movement behavior