Patch-burn grazing (PBG) as a livestock management alternative for fire-prone ecosystems of North America

Abstract

Many rangelands of the world are fire dependent and display a strong interaction between fire and grazing on animal behavior, productivity and ecosystem processes. The application of this fire–grazing interaction as patch-burn grazing (PBG) has recently been promoted in North America to conserve biodiversity and as an alternative for livestock management in fire-prone ecosystems to enhance forage quality and other production benefits. PBG is functionally applied by burning spatially and temporally discrete patches to allow livestock to choose where and when to graze. However, considering that the primary intent of PBG in fire-dependent ecosystems has been for the conservation of biodiversity, we synthesized the peer-reviewed literature to assess PBG as an alternative strategy for livestock management in fire-prone ecosystems. We reviewed the literature to assess PBG as an alternative livestock management approach to optimize animal production and conserve biodiversity in fire-prone ecosystems. We reviewed the results of 83 studies that focused on two main areas: (1) livestock production and inputs and (2) maintaining or improving ecosystem functioning and biodiversity to support sustainable livestock production. PBG can optimize cattle production by offsetting input costs such as supplemental feed, insecticides, herbicides, mechanical brush control, veterinary costs and cross-fencing. PBG can also maintain native herbaceous plant communities that are the resource base for cattle grazing enterprises by reducing woody plant encroachment, stimulating above- and below-ground biomass of native perennial grasses, enhancing nutrient cycling and optimizing plant diversity. PBG creates a habitat mosaic critical for many trophic levels of wildlife, particularly grassland birds, which are currently in decline. Further research is needed to clarify the potential environmental gradients defining applicability of PBG, economic outcomes of PBG, potential gastro-intestinal parasite control with PBG and other metrics of animal production. Overall, PBG is a viable management approach to improve productivity and biodiversity in fire-regulated grassland ecosystems in a manner supported by both fire and grazing disturbances. This is especially true when these communities have other organisms that depend on periodic disturbance and interaction with large animal grazing and is supported by ample empirical research.

Recoupling fire and grazing reduces wildland fuel loads on rangelands

“…, Scasta et al. ). We re‐emphasize the importance of the fire–grazing interaction and time since fire in determining herbaceous biomass accumulation (van Langevelde et al.…”

Moderate patchiness optimizes heterogeneity, stability, and beta diversity in mesic grassland

“…() posed a question: “Should heterogeneity be the basis for conservation?” A decade on, the answer appears to be, Yes—across a breadth of taxa, including birds, invertebrates, and small mammals, landscape‐level heterogeneity has been repeatedly shown to increase two ecosystem properties critical to biodiversity conservation: the structural diversity of vegetation among patches, and dissimilarity in community composition across patches, when compared to homogeneous landscapes (Fuhlendorf, Fynn, McGranahan, & Twidwell, ). These outcomes are compelling and are often sought by ecosystem managers; thus, it is of little surprise that enhancing heterogeneity has become a common objective for conservation and management (McGranahan & Kirkman, ; Beale et al., ; Scasta et al., ).…”

Plant community responses to historical wildfire in a shrubland–grassland ecotone reveal hybrid disturbance response

“…Although burned areas lack A. tridentata, they provide forage resources (perennial grasses and forbs) that are less abundant elsewhere on the landscape. These could be important for both livestock and sage-grouse (Centrocercus urophasianus) chicks (Pennington et al 2016, Scasta et al 2016. Shrub-free patches also provide grassland bird habitat for lark buntings (Calamospiza melanocorys), western meadowlarks (Sturnella neglecta), and grasshopper sparrows (Ammodramus savannarum) found in mixed-grass prairie with taller vegetation (Augustine and Derner 2015).…”

“…Plant communities in these ecosystems have dramatically different historical fire regimes. In contrast, prairie ecosystems in the Great Plains are resistant to fire and the combination of fire and grazing can increase the provisioning of multiple ecosystem goods and services (Fuhlendorf et al 2009, Vermeire et al 2011, Augustine and Derner 2015, Scasta et al 2016. In contrast, prairie ecosystems in the Great Plains are resistant to fire and the combination of fire and grazing can increase the provisioning of multiple ecosystem goods and services (Fuhlendorf et al 2009, Vermeire et al 2011, Augustine and Derner 2015, Scasta et al 2016.…”

“…Sagebrush steppe ecosystems found in North America's Intermountain West are typically intolerant of fire, and frequent fires in these systems can lead to invasion by annual grasses and degradation (Baker 2006, Davies et al 2011, Balch et al 2013. In contrast, prairie ecosystems in the Great Plains are resistant to fire and the combination of fire and grazing can increase the provisioning of multiple ecosystem goods and services (Fuhlendorf et al 2009, Vermeire et al 2011, Augustine and Derner 2015, Scasta et al 2016.…”