02261nas a2200145 4500008004100000245012600041210006900167300001100236490000800247520173500255653001401990100001802004700001902022856007402041 2002 eng d00aEffects of grazing intensity on growth, reproduction, and abundances of three palatable forbs in Kansas tallgrass prairie0 aEffects of grazing intensity on growth reproduction and abundanc a23 -330 v1593 a
The effects of different intensities of cattle grazing on the aboveground growth, reproduction, and abundances of three palatable forbs were studied in native tallgrass prairie. Populations of Aster ericoides, Ruellia humilis, and Amorpha canescens were sampled at peak flowering during the 1993-1995 growing seasons in four annually-burned sites varying in cattle stocking density [ungrazed, low, moderate, high]. The three forbs exhibitedreduced shoot growth and/or reproduction under moderate to heavy grazing, and in no case did grazing increase any measure of plant performance. Ruellia showed reduced shoot height and biomass, percentage of stemsflowering, and reproductive biomass in response to grazing. Aster showed decreases in shoot biomass and height with grazing. Amorpha showed no change in shoot or reproductive biomass, but a decrease in percent of flowering stems and in reproductive allocation with grazing. Patterns in the percentage of stems grazed indicated generally high but variable palatability among these species. By contrast, the three species showedinconsistent population response to grazing. Abundance (frequency) of all three species indicated no short-term change between years in response to grazing intensity. Responses of these species differ considerably from those of most other perennial tallgrass prairie forbs that are unpalatable, unconsumed, and increase in performance (e.g. size, abundance) due to release from competition from the dominant grasses under ungulate grazing. The results demonstrate that immediate aboveground growth and reproductiveresponses of established adults to grazing are not good predictors of grazer effects on population abundances in tallgrass prairie.
10aflowering1 aHickman, K.R.1 aHartnett, D.C. uhttp://ipsapp008.lwwonline.com/content/getfile/5220/57/6/fulltext.pdf