Survival of grassland plants after wildfire shows resilience, minimal lasting impact

Survival of grassland plants after wildfire shows resilience, minimal lasting impact

Posted: Thursday, March 24, 2011 8:02 pm

Rangeland Ecology & Management– Prescribed fires are often used to control undesirable species and enhance herbaceous biomass production. But what are the results when a wildfire burns out of control? In March 2006, more than 367,000 hectares burned in wildfires known as the East Amarillo Complex that raged in the U.S. Texas Panhandle. By studying the survival and regrowth of plants from these wildfires, scientists can learn more about its effects on the ecosystem.

An article in the January 2011 issue of the journal Rangeland Ecology & Managementreports on a study of the effects of wildfire on perennial grass mortality and peak standing crop at one, two, and three years following the Texas fires. Plots of grasses in urned areas were compared with plots in unburned areas.

The wildfires increased perennial grass mortality. The impact was strongest in the first growing season after the fire, but  greater growth occurred for three successive years  following the fire.  A significant effect was still noted after three growing seasons.

Wildfire effects on the standing crop of grasses, however, were more short-lived. The burn sites showed modest to no impact on standing crop in the following years. This study did not find a link between frequency of individual plant mortality and standing crop production.

Similar  growth  following a fire may occur  because the death of individual plants releases resources that can be used by surviving plants. Burned sites were able to produce the same biomass as unburned sites because surviving plants could “take up the slack” using the additional  resources that would have been used by the dead plants.

Researchers found that these plants exhibited a resilience that likely reflects the historical role of fire in this ecosystem. Grassland plant species have endured frequent cycles of burning. Adaptations to these conditions, such as bud banks at or below ground level or the production of surplus branch meristems, are common.

The effects of these wildfires were found to be similar to the effects of prescribed burns. The minimal  impacts associated with these wildfires suggests that additional land management in unnecessary to counter their effects.

Full text of the article, “Biomass Not Linked to Perennial Grass Mortality Following Severe Wildfire in the Southern High Plains,” Rangeland Ecology & Management,Vol. 64, No. 1, January 2011,is available at http://www.srmjournals.org/doi/full/10.2111/REM-D-10-00071.1.

Posted 3.24.11

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