Do spatial simulations change reference conditions?

The reference condition is the expected proportions of reference vegetation classes per ecological system (hereafter, system) within an area and has been measured with non-spatial state-and-transition simulation models (STSM). We aimed to Demonstrate that reference conditions varied between non-spatial and spatial STSMs from an eastern Nevada USA landscape. The same STSM database was used to simulate the non-spatial and spatial reference conditions, except additional input were added for spatial simulations. The reference condition was obtained from averaged vegetation class proportions of replicated simulations. Mean fire return intervals (MFRI) were always shorter in spatial than non-spatial simulations. The dissimilarity between the spatial and non-spatial reference conditions was generally higher for smaller systems and those with long MFRIs (≥ 100 years). Non-spatial and spatial reference conditions were comparable for large systems with 50-100-year MFRI. The proportions of older v..., Study Area. The south Snake Range Area of Interest (AOI) of 161,569 ha includes lands primarily managed by the Bureau of Land Management, Great Basin National Park, and US Forest Service, with private lands inholdings and larger tracts at the periphery of the AOI. The AOI is located in east-central Nevada adjacent to the Utah border (Wheeler Peak at 38°59’25.80”N, 114°20’09.48”W). Great Basin vegetation of the south Snake Range is highly diverse as the elevation gradient ranges from 1,219 m to over 3,900 m.
Mapping: One 161,569 ha image from WorldView 2/3 pan-sharpened 0.65 m resolution multispectral satellite imagery (Maxar Space Systems, acquired by Lanteris Space Systems in 2025, https://lanterisspace.com/) was captured on June 22, 2022. Remote sensing analysis was conducted with the software ERDAS Imagine® from Hexagon AB (https://hexagon.com) applied to WorldView imagery.
Remote sensing methodology is explained in Provencher et al. (2021: Climate 9, 79, 2024: International Journal ..., # Do Spatial Simulations Change Reference Conditions?

There are one simulation database, one supporting simulation raster folder, one folder of tabular results of vegetation classes by systems and analyses, one folder of raster results of vegetation classes by systems for three years, and one PDF of the vegetation description:
(A) \"South\_Snake\_Range\_NRV.zip\" zipped folder contains the simulation database \"SouthernSnakeRange_Spatial-NRV.ssim,\" which requires the freeware Syncrosim (Syncrosim version 3.1.12 or later; downloaded from [www.apexrms.com](http://www.apexrms.com)) and packages ST-Sim (package ST-Sim version 4.5.3 or later; obtained remotely from within Syncrosim), and the input and output database (SouthernSnakeRange_Spatial_NRV.ssim.data). The database of input and output data was created and managed by Syncrosim during simulations and should not be tampered with as all parameters and data to run the simulations are contained within. The Authors have never worked within th..., ,