Recoupling cross-scale interactions in tall fescue-invaded tallgrass prairie

"Recoupling cross-scale interactions in tall fescue-invaded tallgrass prairie"

This article was published online Oct. 11, 2021 in Landscape Ecology.

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Abstract

Context

Vegetation quantity and quality influence the degree to which large grazers shape grassland structural heterogeneity. Invasive plants threaten the function of cross-scale interactions that exist when multi-scale effects such as fire and grazing interplay to form patterns of grassland structural heterogeneity.

Objectives

We investigated how grazing pressure and time since fire at the patch scale influenced patch utilization and production as well as forage quality in experimental grassland pastures dominated by an invasive grass, tall fescue (Schedonorus arundinaceous). We also assessed the response of tall fescue utilization and production to interactive fire-and-grazing under moderate and heavy grazing pressure.

Methods

We collected data on vegetation quantity and quality over two grazing seasons to evaluate the role of fire and grazing across time in shaping structural heterogeneity among patches in invaded tallgrass prairie in Iowa, USA. We anticipated greater initial patch-scale utilization in patches burned for the first time in two years than patches not burned in two years in our experimental pastures. We expected that greater utilization in recently-burned patches would reduce tall fescue production, mostly where grazing pressure was highest.

Results

The contrast in the availability of live herbage between patches was half the level typical for native-dominated tallgrass prairie. Under increased grazing pressure, the interplay between fire and grazing did not result in greater broad-scale heterogeneity (among-patch heterogeneity) or an invasive grass reduction in experimental pastures. Yet, increased grazing early in the season did promote native-grass production in this invaded grassland landscape.

Conclusion

Our results suggest that the dominance of tall fescue mediates the lack of structural heterogeneity induced by patch-level prescribed fire and grazing. Unlike native perennial grasses, tall fescue provides access to forage in unburned patches through its low-stature growth form. Diminished cross-scale interactions through a weak coupling of fire and focal grazing in invaded tallgrass prairie may facilitate structural homogenization of fire-dependent grassland.

Keywords:     Cross-scale interactions; Forage quality; Herbivore-plant interactions; Prescribed fire; Pyric herbivory; Schedonorus arundinaceus

Citation

Raynor, Edward J., Heidi L. Hillhouse, Diane M. Debinski, James R. Miller, and Walter H. Schacht. "Recoupling cross-scale interactions in tall fescue-invaded tallgrass prairie." Landscape Ecology (2021): 1-17.

Variation in prescribed fire and bison grazing supports multiple bee nesting groups in tallgrass prairie

This article was published July 30, 2021 in Restoration Ecology.

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Abstract

Fire and grazing are historic ecosystem drivers of tallgrass prairie and both are used for restoration management today. The effects of these drivers on animal taxa are still incompletely resolved, especially for wild bees, a growing conservation and restoration priority. Fire and grazing could affect wild bee communities through structural changes to nest site availability via changes to soil conditions, vegetative cover, and availability of plant stems. Here, we sought to determine how different bee nesting groups are affected by the combination of fire and bison grazing management strategies. We grouped bee species by nesting substrate (ground, stem/hole, large cavity) because we expect the availability of these substrates to vary with the application of prescribed fire and grazing. We collected bees in restored and remnant high-quality tallgrass prairie and analyzed whether the proportion of each nesting group within the total bee community was predicted by fire and/or grazing. Ground-nesting bees reached their greatest proportion in bee communities immediately after prescribed fire, but declined proportionally over time since the last burn. Stem-/hole-nesting bees reached their highest proportion in the bee community with infrequent fire (6-year interval) and differed in their response to fire depending on the presence/absence of bison. Sampling year affected bee nesting groups and we found that nesting groups did not change in concert (i.e. different nesting groups had different good and bad years from each other). Our results show that spatiotemporal variation of prescribed fire and bison grazing is essential for conservation of multiple bee nesting groups.

Citation

Bruninga‐Socolar, Bethanne, Sean R. Griffin, Zachary M. Portman, and Jason Gibbs. "Variation in prescribed fire and bison grazing supports multiple bee nesting groups in tallgrass prairie." Restoration Ecology (2021): e13507.

Evolving Management Paradigms on U.S. Fish and Wildlife Service Lands in the Prairie Pothole Region

This article was published online January 11, 2019 in the journal Rangelands.

https://doi.org/10.1016/j.rala.2018.12.004

Abstract

• The US Fish and Wildlife Service manages nearly 1 million acres of wetlands and grasslands in the Prairie Pothole Region.

•  Initial management paradigms focused on nesting cover for waterfowl and other birds, which led to idling prairies, and seeding former croplands to non-native plants.

•  Current paradigms encompass a broader focus on ecological integrity and biological diversity, resulting in increased defoliation of prairies and seeding former croplands to native plants.

Keywords: U.S. Fish and Wildlife Service; Prairie Pothole Region; land management; waterfowl; fire; grazing

Citation

Dixon, Cami, Sara Vacek, and Todd Grant. "Evolving Management Paradigms on US Fish and Wildlife Service Lands in the Prairie Pothole Region." Rangelands (2019).

Corresponding author: Cami Dixon (Cami_dixon “at” fws.gov)