Carlton M. Britton

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.

Grass Repellency to the Red Imported Fire Ant

Abstract The red imported fire ant (Solenopsis invicta Buren) is an invasive pest that causes ecological disturbance and economic damage to habitats worldwide. Since its introduction to the United States 75 years ago, the ant has spread across the southeast through Texas into California and causes over

Chihuahua's Cattle Industry and a Decade of Drought: Economical and Ecological Implications

6.5 billion in damages. Conventional control techniques have not proven effective or long-lasting, leading to a search for alternative methods. We examined the ability of WW-B.Dahl Old World bluestem (Bothriochloa bladhii [Retz] S.T. Blake), increasingly used in pastures, to limit or reduce ant infestations. Pastures planted with WW-B.Dahl had about one-third the fire ant mounds found in adjacent pastures of native grass or coastal bermuda (Cynodon dactylon [L.] Pers) grass, and the difference is statistically significant (P = 0.0006). No difference was found in the number of ants collected in bait cups or in mound vitality ratings, suggesting that more than one measure of ant infestation is needed to accurately assess ant populations. A reduction in fire ant mounds can improve the efficiency of haying operations and reduce wildlife impacts, suggesting broad uses for WW-B.Dahl in ant-infested areas.

Season and Intensity of Burning on Two Grass Species of the Chihuahuan Desert

Chihuahuas Cattle Industry and a Decade of Drought: Economical and Ecological Implications

Effects of burns conducted in summer and winter on vegetation of Matagorda Island, Texas.

Abstract We investigated effects of three burning seasons under two simulated fuel loads on plant mortality and basal area of small and large blue grama (Bouteloua gracilis [H.B.K.] Lag) and broomgrass muhly (Muhlenbergia rigida [H.B.K.] Lag) plants in the southern Chihuahuan Desert of Mexico. We simulated prescribed fire with a portable propane burner calibrated to match time and temperature curves reached at 1 700 kg · ha−1 and 2 800 kg · ha−1 fine fuel loads. Large (initial basal area > 10 cm2) and small (initial basal area ≤ 10 cm2) plants were used. For each species, we randomly treated 50 plants in each size class each season at each fuel load; 50 control plants of each species and size received no fire treatment. We estimated basal area change from measurements recorded photographically. Blue grama mortality was affected by season of burning, simulated fuel load, and plant size. Small blue grama plants had higher mortality than large plants. Burning at the high fuel load in winter increased basal area of large blue grama plants; in contrast, basal area was not affected by summer burning, and was reduced by spring burning with high fuel load. Basal area of broomgrass muhly plants was reduced by summer and winter burning and these responses were independent of fuel load and plant size. Our results suggest that winter is the most suitable season for prescription burning to improve southern Chihuahuan Desert grasslands: prescribed fire during this time reduced basal area of broomgrass muhly plants, had the highest mortality on broomgrass muhly, had a positive effect on basal area of small blue grama plants, and had no effect on basal area of large blue grama plants.

Production and Nutritional Attributes of Tobosagrass Following Burning

Abstract We conducted prescribed fires on Matagorda Island, Calhoun County, Texas, in late summers (August) and early winters (January) of 1992–1993 and 1993–1994 to determine responses of vegetation and litter. There were reduced litter loads 1 year after burning, but they approached pre-burn levels 2 years after burning. There was no difference in production of grasses, forbs, or the Juncus and other-Cyperaceae complex 1 year after burning. There was a significant difference in production of Juncus and other Cyperaceae when years were compared. We presume this was caused by differences in precipitation between years. There was no difference in percentage frequency between burned and control plots 1 year after burning for most species examined. However, burning in summer significantly increased occurrences of coastal mistflower (Conoclinium betonicifolium), Fabaceae, and Cyperaceae (other than Juncus) over control plots 1 year after treatment. Beach groundcherry (Physalis cinerascens) and Fabaceae also were increased by burning in summer 2 years following treatment. Prescribed burning did not affect density of vertical structure. Because coastal barrier islands serve as important wintering grounds and stopovers for many migratory birds, we recommend conducting burns in late summer every 2–5 years to increase incidence of legumes and other forage for wildlife.