An overview of the ATLSS Program is presented. The program has produced a set of models of spatially explicit species index, population demography, and ecosystem process models that are available for applications. In addition, the program has supported field studies designed to produce data for model construction and validation. This report describes the following aspects of the program.

The Spatially Explicit Species Index (SESI) models quantify relative effects of hydrologic conditions on the habitat suitability of species. There are several currently available ATLSS SESI models:

• Cape sable seaside sparrow breeding potential index (Version 1.1)
• Snail kite breeding potential index (Version 1.1)
• Long-legged wading bird foraging condition index (Version 1.1)
• Short-legged wading bird foraging condition index (Version 1.1)
• Empirically-based fish biomass index (Version 1.1)
• White-tailed deer breeding potential index (Version 1.1)
• American alligator breeding potential index (Version 1.1)
• Everglades and slough crayfish (Version 1.1)
• Apple snail SESI model (Version 1.1)

The ATLSS SESI models accomplish the following. They produce values for habitat suitability ranging from 0.0 to 1.0 for all 111,000 cells of the 500 x 500 m array. These can be calculated for every individual year in the multi-year sequence (1965-1995 for the Restudy scenarios), or averages can be taken over any set of years (e.g., wet years, dry years, all 31 years). The SESI models are intended to be used to make relative comparisons between scenarios, not to produce absolute evaluations of habitat quality. The output can be viewed using the ATLSS Data Viewer, which allows viewing at any scale and performing of statistics. The ATLSS Data Viewer is available to all agencies that are interested. Training sessions can be scheduled when requested.

There are currently three available ATLSS Demographic Models. The ATLSS demographic models are spatially explicit individual-based (SEIB) models of the dynamics of the populations:

• Cape sable seaside sparrow demographic model (SIMSPAR - Version 1.3)
• Snail kite demographic model (EVERKITE - Version 3.1)
• American alligator (Version 1.1)

The ATLSS Structured Functional Group models simulate the size-structured and biomass dynamics of the population. There is currently one available ATLSS Structured Functional Group model:

• Freshwater fish dynamics (ALFISH - Version 3.1.17)
• There are background models that provide landscape information for other ATLSS models:
• High Resolution Topography (HRT - Version 1.4.8)
• Vegetation productivity (HTDAM -Version 1.1)
• High Resolution Hydrology (HRH - Version 1.4.8)

ATLSS model runs for scenario evaluations can be made in the following ways for particular models. The Snail kite demographic model (EVERKITE) is available in PC form for use (can be downloaded from Web) and user support for those wanting to use this model. Alternatively, this model will be run at the University of Miami and results posted. Currently, the remaining ATLSS models can be run at the University of Tennessee, which is funded to carry out several such runs. Results will be posted. Also, these models can be installed at agencies that have Unix workstations. A NSF-funded project at the University of Tennessee is currently underway to allow dispersed resource managers to access remotely the capabilities of the SInRG (Scalable Intracampus Research Grid) at the University of Tennessee. This will allow users at resource agencies in south Florida, with relatively little computer expertise, to initiate ATLSS simulations on the computers at the University of Tennessee.

Technical documentation of ATLSS models is available on the ATLSS web site (ATLSS.ORG) and listed in ATLSS Program Publications (available) - and will be further improved. Open literature publications exist for the available ATLSS models. Nearly all models have appeared in open-literature, peer-reviewed papers (see ATLSS Publications). An internal USGS panel reviewed the ATLSS Program in May 2002. Additional review by the Model Refinement Team of CERP is planned.

Validation of models is an important issue. Some degree of model validation has been performed on some models (SIMSPAR, ALFISH). Model validation on other models depends on the availability of data sets. Now data sets are becoming available for several species, and new data for others. A "validation tool", which can be applied along with the ATLSS Data Viewer, allows empirical data (e.g., nest success rate, fish biomass) to be compared spatially with SESI index values at any spatial scale. Statistical testing can be done using spreadsheets programs. Validation is being done, or will be done soon on Cape Sable seaside sparrow, snail kite, and American alligator SESI models.

User interfaces for running models and analyses have been developed. For running SESI models, only a UNIX platform is currently available, but extension to PC is planned. The snail kite model (EVERKITE) runs on a PC.

Output of the SESI models can be displayed on the ATLSS Data Viewer. This will be extended to the demographic models.

ATLSS models nearly completed or under development include:

• Vegetation succession model
• Alligator structured population model
• Apple snail structured population model
• Crayfish structured population model
• Roseate spoonbill SESI model
• Estuarine fish dynamics

Contact: D.L. DeAngelis, U.S. Geological Survey, Biological Resources Division, Department of Biology, University of Miami, P.O. Box 249118, Coral Gables, FL 33124; Phone: 305-284-1690, Fax: 305-284-3030, don_deangelis@usgs.gov

(This abstract was taken from the Greater Everglades Ecosystem Restoration (GEER) Open File Report 03-54)

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