Surveillance of Host-Seeking Ticks in the Flint Hills Region (USA) and Associations with Environmental Determinants

Diversity and phenology of host-seeking ticks were studied in the Flint Hills region of the USA, which is a prominent region for raising beef cattle. Between a two-year period from 2015–2017, ticks were collected using the dragging method from 9 distant locations, 6 of which were studied seasonally and 3 continuously throughout the study period. Of the 10,055 ticks collected, 76.5% were the Lonestar tick (Amblyomma americanum), 14% were American dog tick (Dermacentor variabilis), and 9.1% were Gulf Coast tick (A. maculatum). The blacklegged tick, Ixodes scapularis were also found, albeit in low numbers. The host-seeking activity of all three predominant tick species peaked once during the late spring, summer months in the region. The phenology of all ticks was positively associated with accumulated temperature and photoperiod. Additionally, the Normalized Vegetation Difference Index (NDVI) was associated with A. americanum, and saturation deficit and relative humidity were negatively associated with D. variabilis and A. maculatum tick phenology, respectively. This finding is useful to predict the times during a year in which cattle are at higher risk for exposure to these ticks and associated pathogens.

Effects of prescribed fire timing on grazing performance of yearling beef cattle, forage biomass accumulation, and plant community characteristics on native tallgrass prairie in the Kansas Flint Hills

Recent research demonstrated that mid- or late-summer prescribed fires can be employed to manage sericea lespedeza (Lespedeza cuneata) infestations in the Kansas Flint Hills. The effects of prescribed fire applied during the growing season (i.e., August to October) on grazing performance of yearling cattle have not been evaluated. Native pastures (n = 18; 22 ± 4.0 ha) were grouped by watershed and assigned randomly to 1 of 3 prescribed-fire treatments: spring (7 April ± 2.1 d), summer (21 August ± 5.7 d), or autumn (2 October ± 9.9 d). Yearling beef cattle were grazed from May to August at a targeted stocking density of 280 kg live-weight ˖ ha -1 following prescribed fire application. Forage biomass accumulations, soil cover, plant species composition, and root carbohydrate concentrations in four native plant species were evaluated. Total BW gains and ADG were greater (P = 0.01) for cattle that grazed the spring and summer prescribed-fire treatments compared with those that grazed the autumn prescribed-fire treatment. As a result, final BW were greater (P = 0.04) in the spring and summer treatments than the autumn treatment. Conversely, forage biomass accumulations did not differ (P = 0.91) between fire regimes. Proportions of bare soil were greater (P < 0.01) in the spring treatment compared with the summer and autumn treatments, whereas proportions of litter on the soil surface were greater (P < 0.01) in summer- and autumn-burned pastures compared with spring-burned pastures. Total basal cover of graminoids and forbs did not differ (P ≤ 0.15) between prescribed fire treatments. Likewise, total basal cover of C3 or C4 perennial grasses did not differ (P ≥ 0.23) between prescribed fire treatments. No treatment differences (P = 0.24) in root starch or root water-soluble carbohydrate concentrations in big bluestem (Andropogon gerardii), little bluestem (Schizachyrium scoparium), Indiangrass (Sorghastrum nutans), or purple prairieclover (Dalea purpurea) were detected. These data were interpreted to suggest that summer or autumn prescribed fire can be applied without reducing forage biomass accumulations, root carbohydrate concentrations in key native plant species, or considerably altering native plant populations compared with conventional spring-season prescribed fire; however, summer prescribed fire could be favored over spring or autumn prescribed fire to both maintain stocker cattle growth performance and to achieve control over sericea lespedeza.

Effects of prescribed fire timing on vigor of the invasive forb sericea lespedeza (Lespedeza cuneata), total forage biomass accumulation, plant-community composition, and native fauna on tallgrass prairie in the Kansas Flint Hills

The predominant grazing management practice of the Kansas Flint Hills involves annual prescribed burning in March or April with post-fire grazing by yearling beef cattle at a high stocking density from April to August. There has been a dramatic increase in sericea lespedeza (Lespedeza cuneata [Dumont] G. Don) coincident with this temporally-focused use of prescribed fire in the Flint Hills region. The species is an aggressive invader and a statewide noxious weed in Kansas. Control has generally been attempted using repeated herbicide applications. This approach has not limited proliferation of sericea lespedeza and resulted in collateral damage to non-target flora and fauna. Alternative timing of prescribed fire has not been evaluated for its control. Our objectives for this 4-yr experiment were to (1) document the effects of prescribed burning during early April, early August, or early September on vigor of sericea lespedeza, standing forage biomass, and basal cover of native graminoids, forbs, and shrubs and (2) measure responses to fire regimes by grassland bird and butterfly communities. Whole-plant dry mass, basal cover, and seed production of sericea lespedeza were markedly less (P < 0.01) in areas treated with prescribed fire in August or September compared with April. Forage biomass did not differ (P ≥ 0.43) among treatments when measured during July; moreover, frequencies of bare soil, litter, and total basal plant cover were not different (P ≥ 0.29) among treatments. Combined basal covers of C4 grasses, C3 grasses, annual grasses, forbs, and shrubs also did not differ (P ≥ 0.11) between treatments. Densities of grasshopper sparrow (Ammodramus savannarum), dickcissel (Spiza americana), and eastern meadowlark (Sturnella magna) were not negatively affected (P > 0.10) by mid-summer or late-summer fires relative to early-spring fires. There were no differences (P > 0.10) in densities of grassland-specialist butterfly species across fire regimes. Under the conditions of our experiment, prescribed burning during summer produced no detrimental effects on forage production, desirable non-target plant species, grassland birds, or butterfly communities but had strong suppressive effects on sericea lespedeza. Additional research is warranted to investigate how to best incorporate late-summer prescribed fire into common grazing-management practices in the Kansas Flint Hills.