L-Range Background

L-Range is a localized version of the G-Range model and can represent generalized changes in vegetation through time for very large or very small areas. Being derived from G-Range, the background provided for that model applies.

G-Range proved helpful in analyzing global changes in rangelands, but being able to model forage dynamics for herbivores at finer spatial scales would allow management questions to be addressed. G-Range may be used to model country-level responses, for example, by masking out other areas, but it is inefficient in limits the resolution of landscapes cells that can be used (since the spatial layers must be global, even if a country is being simulated). We modified G-Range to create L-Range, which uses one of the spatial layers provided to it to set the limit of the area being simulated. With that, large (such as 100 km) or small (30 m) landscape cells may be simulated.

A suite of spatial data are used by L-Range, matching those used in G-Range but supplied by the user for their area of interest. Parameters are provided for landscape units that the user defines (with examples available). Parameters combine with computer code to describe the means by which plants grow and compete for soil nutrients, water, space, and light. Like Century, herbivore offtake is represented, with forage removed from the landscape and a portion of nutrients returned to the landscape through animal wastes. Fire and fertilization of landscapes may be represented. A graphical user interface allows users to explore model output.

L-Range may be applied to an area and used directly. It is also well-suited to being edited to join with other tools that simulate hydrology, atmospheric moisture transport, or other factors. The most common model connected to L-Range allows individual herbivores to be represented in an agent-based context, so that wildlife may consume forage and families may own livestock for which herders make decisions about animal stocking and disributions. L-Range has been joined with our DECUMA model, M. Zarria's ANDES model, and Dr. R. Warrier's SPIRRAL model. These coupled-systems approaches allow ecosystem services to be simulated in L-Range and passed on to the household model. Herders make decisions about where to graze animals based on the ecosystem services, pass on to the ecosystem model L-Range. The decisions made by people may in turn alter ecosystem services, with patterns such as grazing reserves or overgrazing simulated.