University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln Papers in Natural Resources Natural Resources, School of 7-2013 Seasonal Fires, Bison Grazing, and the Tallgrass Prairie Forb Arnoglossum plantagineum Raf. Stephen L. Winter [email protected] Karen R. Hickman Oklahoma State University Carla L. Goad Oklahoma State University Samuel D. Fuhlendorf Oklahoma State University, [email protected] Mark S. Gregory Oklahoma State University Follow this and additional works at: https://digitalcommons.unl.edu/natrespapers Part of the Natural Resources and Conservation Commons, Natural Resources Management and Policy Commons, Other Environmental Sciences Commons, and the Other Plant Sciences Commons Winter, Stephen L.; Hickman, Karen R.; Goad, Carla L.; Fuhlendorf, Samuel D.; and Gregory, Mark S., "Seasonal Fires, Bison Grazing, and the Tallgrass Prairie Forb Arnoglossum plantagineum Raf." (2013). Papers in Natural Resources. 449. https://digitalcommons.unl.edu/natrespapers/449 This Article is brought to you for free and open access by the Natural Resources, School of at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Papers in Natural Resources by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. R E S E A R C H N O T E ABSTRACT: Fire and grazing can interact to affect the structure and composition of vegetation com- munities in a manner that may differ from the effects of fire or grazing that occurs in isolation of the other. In order to better understand the effects of a fire-grazing interaction at the level of an individual plant species, we studied the response of a perennial tallgrass prairie forb, Arnoglossum plantagineum Raf., to the interaction of spring and summer fires with grazing by bison (Bison bison L.). During one field season (2006), we collected data in areas that had been treated with summer fires while in a • subsequent field season (2007) we collected data in areas that had been treated with spring fires. Many measures of plant growth (plant height, vegetative biomass, and total biomass) and reproductive effort (reproductive biomass, indices of flowering plant density) suggested greater resource availability for Seasonal Fires, individuals of A. plantagineum growing in areas that had been recently burned and were being heavily grazed by bison. However, the response of these variables to the fire-grazing interaction often varied Bison Grazing, and among differing topographical positions. Our results demonstrate that the interaction of fire and bison grazing can further interact with topographical position in tallgrass prairie to affect the growth and the Tallgrass Prairie reproductive effort of the perennial forb A. plantagineum. Forb Arnoglossum Index terms: heterogeneity, patch burn grazing, pyric herbivory, shifting mosaic plantagineum Raf. INTRODUCTION richness of this ecosystem (Freeman 1998; Palmer 2007). Fire may affect the diversity A variety of management tools and of tallgrass prairies by altering competitive techniques are available to natural area Stephen L. Winter1,4 relationships between dominant grasses managers tasked with the preservation, and subdominant forbs; spring fires en- 1 Winona, MN 55987 maintenance, and restoration of tallgrass hance the growth of dominant warm-season prairie ecosystems. Prescribed fire has a grasses, which may then preempt resources Karen R. Hickman2 long history of application in the restora- available to subdominant forbs, resulting tion and management of tallgrass prairies Carla L. Goad3 in reduced forb growth or reproductive ef- (Kollmorgen and Simonett 1965; Hoy fort (Knapp 1984; Hartnett 1990; Hartnett 2 Samuel D. Fuhlendorf 1989), particularly in the context of natural 1991). Frequent spring fires can contrib- Mark S. Gregory2 area management and restoration where ute to greater dominance of grasses with its use is widespread (Curtis and Partch concomitant declines in the abundance of 1948; Helzer 2010; Rowe 2010). The use forbs (Kucera and Koelling 1964; Collins 2 Department of Natural Resource of grazing as a restoration and management and Steinauer 1998). Ecology and Management tool in tallgrass prairies has not been as Oklahoma State University ubiquitous as the use of fire. Certainly, in Grazing in tallgrass prairie can modulate Stillwater, OK 74078 western portions of the tallgrass prairie, community diversity by reducing the there is a long history of cattle (Bos taurus competitive ability of dominant grasses 3 Department of Statistics L.) grazing as an economic activity that when they are grazed and by altering the Oklahoma State University has shaped the ecosystem in areas where environmental conditions at the microsite Stillwater, OK 74078 it has occurred (Malin 1942; Kollmorgen occupied by an individual forb (Collins et and Simonett 1965). In other areas, perhaps al. 1998). Selective grazing of grasses can especially in the eastern portion of this create a favorable growing environment • ecosystem’s range, there has been debate around a prairie forb as a result of greater over the value of large herbivore grazing as levels of light and higher soil temperatures a conservation tool (Williams 1997; Har- (Fahnestock and Knapp 1993, 1994). Prai- rington 1998; Henderson 1998; Davison rie forbs growing among grazed grasses and Kindscher 1999; Howe 1999; Knapp can be characterized by greater biomass 4 Corresponding author: et al. 1999; Leach et al. 1999). than conspecifics in ungrazed areas, exem- [email protected]; 402-310- plifying the relationship between resource 5460 Management of tallgrass prairies is often availability and biomass accumulation focused on manipulating the richness, (Fahnestock and Knapp 1993, 1994; Dam- diversity, and composition of vegetation houreyeh and Hartnett 1997). Somewhat communities (Brudvig et al. 2007). While counterintuitively, prairie forbs growing in vegetation productivity of tallgrass prairies grazed areas can be shorter than conspecif- is driven largely by a few species of warm ics growing in ungrazed areas (Fahnestock Natural Areas Journal 33:327–338 season grasses (Knapp et al. 1998), forbs and Knapp 1993, 1994; Damhoureyeh make the greatest contribution to species and Hartnett 1997), suggesting that forbs Volume 33 (3), 2013 Natural Areas Journal 327 growing among ungrazed grasses need to selective grazing of grasses within recently multiple species of tallgrass prairie forbs, be taller to obtain sufficient light resources. burned patches, contrasting with the limited but we were constrained by limitations on When prairie forbs are able to capitalize on grazing of grasses within patches that have the time available for field activities. increased resource availability as a result not burned recently (Coppedge et al. 1998; of altered competitive interactions with Winter et al. 2012). We conducted our study to gain insight neighboring grasses, they may allocate into whether a prairie forb experiences biomass in a manner that differs among spe- However, grassland landscapes are charac- different levels of resource availability in cies: forbs that are primarily asexual may terized by topoedaphic variability that also the different patches characterizing the increase total biomass while forbs that are affects vegetation communities (Barnes and shifting mosaic of a fire-grazing interac- primarily sexual may increase reproductive Harrison 1982; Knapp et al. 1993; Dodd tion. While we did not explicitly measure biomass, number of florets, or number of et al. 2002; Winter et al. 2011). Slope and resource availability (e.g., levels of light, seeds (Fahnestock and Knapp 1993, 1994; aspect are topoedaphic features that influ- water, or nutrients) in patches with different Damhoureyeh and Hartnett 1997). ence the microsite conditions experienced burn histories, we assume our measures by individual plants. Contrasting slope of plant growth and reproductive effort A management practice gaining increased and aspect features can be characterized infer resource availability. Specific null attention in the last decade is known vari- by contrasting levels of soil temperature hypotheses that we tested in our research ously as patch burn grazing, heterogeneity and soil moisture content (Ayyad and Dix were: (1) measures of plant growth (height, management, the fire grazing interaction, 1964), contrasting plant leaf temperatures vegetative biomass, and total biomass) or pyric herbivory (Fuhlendorf and Engle (Smith et al. 1983), and contrasting level does not differ between plants growing in 2001; Fuhlendorf et al. 2006; Fuhlendorf et of response by grasses and forbs to altered patches that were recently burned and were al. 2009). This practice capitalizes on the levels of nutrient availability (Benning and being heavily grazed and plants growing profound influence of fire on the distribu- Seastedt 1995). Thus, any shifting mosaic in patches that were not recently burned tion and behavior of grazing animals to alter of altered competitive dynamics between and were being minimally grazed; and (2) vegetation heterogeneity across landscapes dominant grasses and subdominant forbs measures of reproductive effort (number of (Fuhlendorf et al. 2004; Vermeire et al. arising from a fire-grazing interaction may floral structures, reproductive biomass, and 2004; Fuhlendorf et al. 2006; Coppedge et be constrained or modulated by a pre-ex- density of flowering individuals) does not al. 2008; Allred et al. 2011; McGranahan isting template of heterogeneity imposed