Biomass Not Linked to Perennial Grass Mortality Following Severe Wildfire in the Southern High Plains

Abstract

In March 2006 the East Amarillo Complex (EAC) wildfires burned over 367 000 ha of short and mixed grass prairie of the southern High Plains, USA. We studied EAC wildfire effects on perennial grass mortality and peak standing crop on Deep Hardland and Mixedland Slopes ecological sites. Deep Hardlands were dominated by blue grama (Bouteloua gracilis H.B.K. [Griffiths]) and buffalograss (Buchloe dactyloides [Nutt.] Engelm.); common species on Mixedland Slopes were little bluestem (Schizachyrium scoparium [Michx.] Nash.) and sideoats grama (Bouteloua curtipendula [Michx.] Torr.) with scattered sand sagebrush (Artemisia filifolia Torr.) sometimes present. We hypothesized that perennial grass mortality would increase and standing crop would decrease following severe wildfire, and that these responses would be greater than documented prescribed fire effects. Frequency of perennial grass mortality was higher on both sites in burned areas than nonburned areas through three growing seasons following wildfire; however, standing crop was minimally affected. Results suggest that post-wildfire management to ameliorate wildfire effects is not necessary, and that wildfire effects in this area of the southern High Plains are similar to prescribed fire effects.