Lance T. Vermeire

Patch burning effects on grazing distribution

Abstract Post-fire forage growth is known to be a strong attractant for large herbivores. However, fire has generally been avoided as a grazing distribution tool for fear of localized over utilization of forage resources. Our objectives were to examine whether forage utilization was affected by season of burn, determine cattle grazing preference for burned sites relative to non-burned sites, determine forb response to patch burning, and describe the relationship between end-of-season standing crop and distance from burned sites. Sixteen, 4-ha plots were burned in mid-November or mid-April and left exposed to cattle grazing for the duration of the growing season. Burn treatments were blocked within pastures to allow individual herds access to fall-burned, spring-burned, and non-burned sites. Standing crop estimates for grasses, forbs, and total herbage were made in September by clipping on burned sites and at 50, 100, 200, 400, and 800 m distant from the plots edge. Standing crop was also sampled in exclosures on burned and non-burned sites. Cattle showed no preference for one burn season over the other. Cattle were strongly attracted to burned sites, reducing grass standing crop 78% within burns compared to 19% outside the influence of burns. Grass standing crop decreased in a predictable manner with proximity to burned plots. Forbs increased 60% to 1,095 kg ha−1 on grazed burned plots, but were unaffected by distance from burns. Patch burning can be employed as an effective, inexpensive grazing distribution tool.

Selective control of rangeland grasshoppers with prescribed fire

Abstract Grasshoppers (Orthoptera: Acrididae) are considered among the most damaging rangeland pests, but are necessary for the survival of many wildlife species. Most grasshoppers species are innocuous, but control with insecticides is non-discriminatory among species. The objectives were to evaluate the effects of prescribed burning on the abundance and biomass of grasshoppers and to determine if species could be selectively controlled with prescribed fire. Twenty-four, 4-ha sites were selected in a sand sagebrush-mixed prairie near Woodward, Okla. and blocked by pasture. Plots were randomly assigned fall-, spring-, or non-burned treatments within block with 4 replications per treatment for each of 2 years. Grasshopper biomass and abundance were sampled in late July and early August by sweeping with canvas beating nets. Specimens were weighed to the nearest 0.1 mg and identified to species. Fire treatments had no effects on the total abundance or biomass of grasshoppers across species, with about 10 grasshoppers weighing 4,090 mg per 150 sweeps. Fire effects on the 4 most common species were variable and could be explained by the biology of the insects. Melanoplus bowditchi and M. flavidus were unaffected by fire treatment. Hesperotettix viridis is sensitive to damage to its host plants and was reduced about 88% by fire in either season. Ageneotettix deorum abundance was 65% lower on fall-burned plots. We hypothesize the reduction occurred because the species eggs are laid near the soil surface and exposed to the heat of passing fire. Fire prescriptions may be developed to target species-specific vulnerabilities and reduce pest grasshoppers while maintaining the food base for grasshopper predators.

Western ragweed effects on herbaceous standing crop in Great Plains grasslands.

Western ragweed [Ambrosia psilostachya DC. ], a major forb species in mixed and tallgrass prairies, is considered to have little value for cattle grazing but is an important food item for bobwhite quail [Colinus virgini anus ]. While often thought to be a strong increaser with grazing pressure, information on the actual relationship between western ragweed and grasses is contradictory. Our objectives were to 1) determine the effect of western ragweed on grass standing crop, and 2) determine the effect of vegetation type and grazing on survival and shoot morphology of western ragweed. Western ragweed did not appear to reduce grass standing crop. Instead, standing crop (40 to 620 kg ha - 1 ) and density (6 to 41 shoots m - 2 ) of western ragweed were positively related to grass and grassforb standing crop in mixed prairie. Standing crop of western ragweed was not related to grass standing crop in tallgrass prairie. Competitive thresholds for western ragweed in mixed and tallgrass prairies appear to be above the levels observed in this study. Density of western ragweed shoots decreased over the growing season under both grazed and ungrazed treatments. Survival of western ragweed shoots from June to September was greater in mixed prairie (81%) than in tallgrass prairie (63%) and was greater in ungrazed (76%) than grazed plots (68%). Western ragweed shoots weighed less per unit of height in tallgrass prairie. Western ragweed shoots in ungrazed plots were taller than shoots in grazed plots but weighed less per unit of height. These differences in shoot morphology are consistent with increased competition for light in tallgrass prairie and in ungrazed sites. Western ragweed may not directly reduce grass standing crop but, rather, increase only when grasses are reduced by other stresses such as improper grazing.

The Other Grazers

and goats – are typically thought of as the primary grazers (and browsers) on rangelands. Yet, this is the proverbial tip of the iceberg, given the many species that utilize rangelands. Even when wildlife species are thrown into the mix, most people think of the large ungulates – deer, antelope, elk, moose, bison, and bighorn sheep. Let’s face it, most rangeland managers, wildlife biologists, and other rangeland users give little or no thought to the more diminutive “other grazers” of rangelands. Rangeland management literature has focused comparatively little attention on the impacts, benefits, and ecosystem interactions of these other grazers. The Society for Range Management’s (SRM) Wildlife Habitat Committee organized and facilitated a symposium for SRM’s annual meeting in Casper, Wyoming (3-4 Feb. 2003) to focus on the less-considered “other grazers,” including worms, insects, rodents, and birds. The purpose of this symposium was to examine the habitat requirements and ecosystem interactions of these diverse invertebrate and vertebrate species inhabiting rangelands. This paper is a synopsis of the eight contributed papers – the titles and authors of which are listed in Table 1. Interested readers may contact the authors for references used in preparing these papers.

Elk Populations in the Western United States and Canadian Provinces

Discover how game agencies count elk, why, and the accuracy of the estimates. DOI:10.2458/azu_rangelands_v26i5_wermeire

Phenology of perennial, native grass, belowground axillary buds in the northern mixed-grass prairie

PREMISE OF THE STUDYnVegetative reproduction from belowground bud banks is the primary driver of grassland systems. Despite the importance of bud banks, the timing of recruitment and the crucial link between formation and maintenance is unknown.nnnMETHODSnWe assessed patterns of belowground bud development, dormancy, and mortality associated with three perennial native grasses in the northern Great Plains. Temperature and soil moisture were measured below the soil surface to determine relationships with belowground bud development.nnnKEY RESULTSnBlue grama (Bouteloua gracilis) generated more buds over winter that remained dormant; whereas, C3 species needle-and-thread (Hesperostipa comata) and western wheatgrass (Pascopyrum smithii), maintained limited dormant buds throughout winter. Soil temperature was a good predictor for C4 species bud production; whereas, soil moisture was a reliable predictor for C3 buds. Distinct differences existed between C4 species blue grama and C3 species needle-and-thread, whereas C3 species western wheatgrass (Pascopyrum smithii) was intermediate, indicating there is likely a species-specific continuum between the C3 and C4 extremes rather than a stark difference.nnnCONCLUSIONSnThe ability to predict belowground bud development is a novel insight to native perennial grasses. Native grass species strategies and adaptability regarding belowground bud bank size and bud phenology are important factors optimizing tiller recruitment given the variable growing conditions. Patterns of bud dormancy and development will provide insight to the underlying mechanisms by which management practices and fluctuations in precipitation amount and growing season length can alter mixed-grass prairie plant community dynamics.