@article {6287, title = {Dynamic plant{\textendash}herbivore interactions between bison space use and vegetation heterogeneity in a tallgrass prairie}, journal = {Remote Sensing}, volume = {15}, year = {2023}, pages = {5269}, keywords = {LTER-KNZ}, doi = {10.3390/rs15225269}, url = {https://www.mdpi.com/2072-4292/15/22/5269}, author = {Ling, Bohua and Raynor, E.J. and A. Joern and Goodin, D.G.} } @article {KNZ001992, title = {Effects of fire and large herbivores on canopy nitrogen in a tallgrass prairie}, journal = {Remote Sensing}, volume = {11}, year = {2019}, chapter = {1364}, abstract = {

This study analyzed the spatial heterogeneity of grassland canopy nitrogen in a tallgrass prairie with different treatments of fire and ungulate grazing (long-term bison grazing vs. recent cattle grazing). Variogram analysis was applied to continuous remotely sensed canopy nitrogen images to examine the spatial variability in grassland canopies. Heterogeneity metrics (e.g., the interspersion/juxtaposition index) were calculated from the categorical canopy nitrogen maps and compared among fire and grazing treatments. Results showed that watersheds burned within one year had higher canopy nitrogen content and lower interspersions of high-nitrogen content patches than watersheds with longer fire intervals, suggesting an immediate and transient fire effect on grassland vegetation. In watersheds burned within one year, high-intensity grazing reduced vegetation density, but promoted grassland heterogeneity, as indicated by lower canopy nitrogen concentrations and greater interspersions of high-nitrogen content patches at the grazed sites than at the ungrazed sites. Variogram analyses across watersheds with different grazing histories showed that long-term bison grazing created greater spatial variability of canopy nitrogen than recent grazing by cattle. This comparison between bison and cattle is novel, as few field experiments have evaluated the role of grazing history in driving grassland heterogeneity. Our analyses extend previous research of effects from pyric herbivory on grassland heterogeneity by highlighting the role of grazing history in modulating the spatial and temporal distribution of aboveground nitrogen content in tallgrass prairie vegetation using a remote sensing approach. The comparison of canopy nitrogen properties and the variogram analysis of canopy nitrogen distribution provided by our study are useful for further mapping grassland canopy features and modeling grassland dynamics involving interplays among fire, large grazers, and vegetation communities.

}, keywords = {LTER-KNZ, fire, grassland canopy nitrogen, grassland dynamics, grazing history, Spatial heterogeneity, Ungulate grazing}, doi = {10.3390/rs11111364}, url = {https://www.mdpi.com/2072-4292/11/11/1364}, author = {Ling, B. and Raynor, E.J. and Goodin, D.G. and Anthony Joern} } @article {KNZ001800, title = {Temporal variability in large grazer space use in an experimental landscape}, journal = {Ecosphere}, volume = {8}, year = {2017}, abstract = {Land use, climate change, and their interaction each have great potential to affect grazing systems. With anticipated more frequent and extensive future drought, a more complete understanding of the mechanisms that determine large grazer landscape-level distribution under varying climatic conditions is integral to ecosystem management. Using an experimental setting with contrasting fire treatments, we describe the inter-annual variability of the effect of landscape topography and disturbance from prescribed spring fire on large grazer space use in years of variable resource availability. Using GPS telemetry, we investigated space use of plains bison (Bison bison bison) as they moved among watersheds managed with variable experimental burn treatments (1-, 2-, 4-, and 20-year burn intervals) during a seven-year period spanning years of average-to-above average forage production and severe drought. At the landscape scale, bison more strongly favored high-elevation and recently burned watersheds with watersheds burned for the first time in 2 or 4 yr consistently showing higher use relative to annually burned watersheds. In particular, watersheds burned for the first time in 4 yr were avoided to lesser extent than other more frequently burned watersheds during the dormant season. This management type also maintained coupling between bison space use and post-fire regrowth across post-drought growing season months, whereas watersheds with more frequent fire-return intervals attracted bison in only the first month post-fire. Hence, fire frequency played a role in maintaining the coupling of grazer and post-fire regrowth, the fire{\textendash}grazer interaction, in response to drought-induced reduction in fuel loads. Moreover, bison avoided upland habitat in poor forage production years, when forage regrowth is less likely to occur in upland than in lowland habitats. Such quantified responses of bison to landscape features can aid future conservation management efforts and planning to sustain fire{\textendash}grazer interactions and resulting spatial heterogeneity in grassland ecosystems.}, keywords = {LTER-KNZ}, doi = {10.1002/ecs2.1674}, url = {https://esajournals.onlinelibrary.wiley.com/doi/full/10.1002/ecs2.1674}, author = {Raynor, E.J. and Anthony Joern and Skibbe, A.M. and Sowers, M. and J. M. Briggs and Laws, A.N. and Goodin, D.G.} } @article {KNZ001753, title = {Foraging decisions underlying restricted space use: effects of fire and forage maturation on large herbivore nutrient uptake}, journal = {Ecology and Evolution}, volume = {6}, year = {2016}, pages = {5843{\textendash}5853 }, type = {Journal Articles}, abstract = {

Recent models suggest that herbivores optimize nutrient intake by selecting patches of low to intermediate vegetation biomass. We assessed the application of this hypothesis to plains bison (Bison bison) in an experimental grassland managed with fire by estimating daily rates of nutrient intake in relation to grass biomass and by measuring patch selection in experimental watersheds in which grass biomass was manipulated by prescribed burning. Digestible crude protein content of grass declined linearly with increasing biomass, and the mean digestible protein content relative to grass biomass was greater in burned watersheds than watersheds not burned that spring (intercept; F1,251 = 50.57, P \< 0.0001). Linking these values to published functional response parameters, ad libitum protein intake, and protein expenditure parameters, Fryxell\&$\#$39;s (Am. Nat., 1991, 138, 478) model predicted that the daily rate of protein intake should be highest when bison feed in grasslands with 400\–600 kg/ha. In burned grassland sites, where bison spend most of their time, availability of grass biomass ranged between 40 and 3650 kg/ha, bison selected foraging areas of roughly 690 kg/ha, close to the value for protein intake maximization predicted by the model. The seasonal net protein intake predicted for large grazers in this study suggest feeding in burned grassland can be more beneficial for nutrient uptake relative to unburned grassland as long as grass regrowth is possible. Foraging site selection for grass patches of low to intermediate biomass help explain patterns of uniform space use reported previously for large grazers in fire-prone systems.

}, keywords = {LTER-KNZ}, doi = {10.1002/ece3.2304}, url = {https://onlinelibrary.wiley.com/doi/full/10.1002/ece3.2304}, author = {Raynor, E.J. and Anthony Joern and Jesse B. Nippert and J. M. Briggs} } @article {KNZ001679, title = {Bison foraging responds to fire frequency in nutritionally heterogeneous grassland}, journal = {Ecology}, volume = {96}, year = {2015}, pages = {1586 -1597}, abstract = {

Foraging decisions by native grazers in fire-dependent landscapes modulate the fire\–grazing interaction. Uncovering the behavioral mechanisms associated with the attraction of grazers to recently burned areas requires understanding at multiple spatial scales in the ecological foraging hierarchy. This study focused on feeding in the area between steps in a foraging bout, the feeding station, as forage chemistry and vegetation architecture play central roles in these fine-scale, feeding-station decisions. The forage maturation hypothesis (FMH) uses the temporal dynamics of forage quality and quantity in grasslands to explain the distribution of large herbivores, but does not address herbivore responses to inter-patch variation caused by fire-induced nutrient increases of forage quality. Using an experimental setting with contrasting fire treatments we describe the effects of variable burn history on foraging kinetics by bison at Konza Prairie Biological Station (KPBS). We assessed the potential to link the FMH in a complementary fashion to the transient maxima hypothesis (TMH) to explain temporal variation in bison responses to grassland forage quality and quantity in response to burning at different temporal frequencies. Forage attributes met predictions of the TMH that allowed us to investigate how forage maturation affects feeding station foraging behavior across watersheds with varying burn frequency. At sites burned in the spring after several years without burning, both bite mass and intake rate increased with increasing biomass at a greater rate during the growing season than during the transitional midsummer seasonal period. In these infrequently burned watersheds, early growing season bite mass (0.6 \± 0.05 g; mean \± SE), bite rate (38 \± 1.5 bites/min), and intake rate (21 \± 2.3 g/min) was reduced by ~15\%, 13\%, and 29\% during the midsummer transitional period. A behavioral response in foraging kinetics at the feeding station occurred where a nonequilibrial pulse of high-quality resource was made available and then retained by repeated grazing over the growing season. Our results provide the first experimental evidence for demonstrating the fine-scale behavioral response of a large grazer to fire-induced changes in forage attributes, while linking two prominent hypotheses proposed to explain spatial variation in forage quality and quantity at local and landscape scales.

}, keywords = {LTER-KNZ}, doi = {10.1890/14-2027.1}, url = {https://esajournals.onlinelibrary.wiley.com/doi/abs/10.1890/14-2027.1}, author = {Raynor, E.J. and Anthony Joern and J. M. Briggs} } @phdthesis {KNZ001732, title = {Ecological hierarchy of foraging in a large herbivore: the plains bison perspective in tallgrass prairie}, volume = {PhD. Dissertation}, year = {2015}, school = {Kansas State University}, type = {Ph.D. Thesis}, address = {Manhattan, KS}, abstract = {

Foraging decisions by native grazers in fire-dependent landscapes reflect fire-grazing interactions. I assessed behavioral responses associated with the attraction of grazers to recently burned areas at multiple spatial scales. (a) I focused on feeding in the area between steps in a foraging bout \– the feeding station \– where forage quality and vegetation architecture underlie these fine-scale decisions. The \‘forage maturation hypothesis\’ (FMH) predicts the distribution of large herbivores based on the temporal dynamics of forage quality and quantity, but does not address herbivore responses to inter-patch variation caused by fire-induced increases of forage quality. The \‘transient maxima hypothesis\’ (TMH) also predicts variable forage quality and quantity, but in response to intermittent disturbance from fire. I described the effects of variable spring burn history to bison foraging and their spatio-temporal distribution at Konza Prairie. Forage attributes met predictions of the TMH to explain how forage maturation affects foraging behavior across watersheds with varying burn frequency. At sites burned in the spring after several years without burning, intake rate increased with increasing vegetation biomass at a greater rate during the early growing season than during the transitional mid-summer period. This foraging behavior occurred in response to a non-equilibrial pulse of high quality resource that set the stage in the burned area, and was then retained by repeated grazing over the growing season. Thus, bison responded increased forage resource availability resulting from transient maxima in infrequently-burned watersheds burned that spring and they intensely used these areas until forage availability and forage regrowth was not possible. (b) At the patch scale, bison selected areas of low-to-moderate grass cover in which to feed and avoided areas of high forb cover in the growing season. During the dormant season, however, bison selected feeding-sites with uniformly high canopy cover in watersheds that were not burned. (c) At the landscape-scale, infrequently burned watersheds (compared to watersheds that were not burned) provided the strongest significant predictor of bison space use in all early growing- and transitional-season months. (d) The probability of habitat selection was driven by availability of high foliar, protein and low-to-intermediate herbaceous biomass throughout the growing season. These results explain the hierarchy of foraging by a dominant consumer in an experimental landscape by linking two prominent hypotheses, TMH-FMH, proposed to explain spatial variation in forage quality and quantity at local and landscape scales.

}, keywords = {LTER-KNZ, Bison; Foraging Behavior; Forage Maturation; Movement; Space Use; Transient Maxima}, url = {http://krex.k-state.edu/dspace/bitstream/handle/2097/20348/EdwardRaynor2015.pdf?sequence=1\&isAllowed=y}, author = {Raynor, E.J.} }