Historical Vegetation, Fuel Loads, and Integrated Resource Information System for Bryce Canyon National Park

Roberts, David; Jenkins, Michael; Wight, Doug

This report details a project to create a comprehensive computer-based resource information system with information on past, current, and potential vegetation composition, and this vegatations response to fuel loads, fire, and predicted fire behavior within Bryce Canyon National Park. The composition and distribution of plant communities across a natural landscape is determined by a complex interaction of environment, interspecies relations and disturbance. Environmental factors associated with particular locations, such as precipitation and temperature regimes, limit the species which occur at a given site to those with metabolisms suited to the environmental conditions. These environmental factors, while variable across the landscape, are relatively constant at a fixed point in space. Consequently, environment acts as a relatively constant constraint on vegetation distribution and composition. With in the usually large set of species which can exist at a given point, interspecies competition further limits the species present at a given time. The ecological characteristics of the species are also rather fixed, and the interspecies relations lead to a fairly directional and predictable change with time, i.e. succession. Disturbance reduces or eliminates some species directly, and leads indirectly to changes in composition through changes in the competitive hierarchy. In contrast to environmental and interspecies effects, the occurrence and effects of disturbance are highly variable, and depend in a complex way on previous disturbance and the current and previous vegetation. Historically fire played an enormous role in determining the characteristics of vegetation in the Western forests. Studies have documented that much of this area was subject to recurrent fires at fairly short intervals, and that these fires created or perpetuated vegetation very different from that now present. Fire suppression has preserved species which would have been reduced or eliminated under a regime of repeated burning and has led to an increase in fuel loads in many natural communities. To return the landscape to a vegetation mosaic similar to that of the historic past information is needed in several related areas. This report addresses the acquisition of baseline information, and its display.