Managing Grassland Vegetation with Winter-Patch Grazing: Potential Benefits to Livestock and Wildlife

View the project final report

• 2016 annual report

Commodities

• Agronomic: grass (misc. perennial)
• Animals: bovine

Practices

• Animal Production: grazing management, rangeland/pasture management, winter forage
• Education and Training: on-farm/ranch research
• Natural Resources/Environment: biodiversity, habitat enhancement, wildlife
• Production Systems: agroecosystems

This study was implemented in winter 2015-16 with heavy winter patch grazing (WPG) of research station and cooperator ranch pastures followed by summer grazing of all research and cooperator pastures. Data on livestock, vegetation, and wildlife attributes were collected according to protocol during Year 1 and are being analyzed.

Two events have altered the trajectory of this project. The first was a severe hailstorm in July 2016 that destroyed all standing vegetation in a large area, including the pastures of one of our cooperators. Lack of sufficient vegetation growth and recovery precludes us from including that cooperator ranch in Year 2 of the study. The second event was a large wildfire in October 2016 that burned substantial portions of 4 of the 8 pastures at the Cottonwood Research Station that were included in this study. We have modified the study to include both WPG and the burn in Year 2.

Year 2 Update:

Cottonwood Research Station: As a result of the fire that burned substantial portions of several pastures at the Cottonwood Station, 6 of our 8 pastures were recombined into 3 pastures; the remaining 2 pastures were maintained in their original configuration (1 WPG and 1 control). Each of the recombined pastures includes a WPG patch, a burned (PBG) patch, and a control (no burn, no winter grazing). A new patch in the remaining WPG pasture and the  WPG areas of the recombined pastures were heavily grazed in winter 2016/2017. Yearling steers grazed each of the study pastures in summer 2017. Due to extreme drought conditions in the area, grazing animals were removed from pastures in mid-July rather than the planned mid-August removal date. Data on livestock, vegetation, and wildlife attributes were collected according to protocol during Year 2 and are being analyzed.

Cooperator Pastures: A new patch was grazed during winter 2016/2017 in the WPG pasture of the remaining cooperator ranch. Cow/calf pairs grazed the WPG and control pastures according to protocol for the entire summer (drought conditions were much less severe compared to Cottonwood). Data on livestock, vegetation, and wildlife attributes were collected according to protocol during Year 2 and are being analyzed.

Year 3 Update:

Data collected during Years 1 and 2 have been summarized and analyzed; reports and manuscripts are being developed and submitted.

Year 4 Update - Final Report Summary:

1) Problem addressed: Traditional range management techniques are commonly used to improve livestock production; these techniques, however, promote development of homogenous vegetation structure/composition and are contributing to reduction of grassland bird habitat.  Interspersion of diverse habitat types throughout a heterogeneous landscape is necessary to preserve habitat for grassland birds and other wildlife species, improve livestock production, and increase resiliency of rangelands to disturbances.  The use of fire to create burned patches in the landscape has been shown to be an effective land and grazing management tool in improving heterogeneity in vegetation structure/composition and habitat for livestock and wildlife in the south and southwest.  However, ranchers in the western region of NCR are very reluctant to burn due to costs, concerns about weed invasion, and potential for changes in carrying capacity.  Using cattle to heavily graze patches in the winter may provide an alternative to patch-burn grazing. This study was designed to determine if winter-patch grazing would be an effective alternative to burning for 1) improving heterogeneity in vegetation structure/composition, 2) improving/maintaining cattle performance, and 3) improving habitat and use of pastures by grassland birds. If successful, this study could provide an alternative to burning for ranchers and land managers interested in developing wildlife habitat while still maintaining good livestock production.

2) Research approach: This study was designed to determine the extent to which winter-patch grazing (WPG) could be used to create heterogeneity in vegetation structure/composition, maintain/improve livestock performance, and improve habitat for grassland birds. The approach used in this study was to create patches within pastures that were grazed heavily in winter and then allow cattle to graze in those pastures and select the WPG patch or non-patch areas; pastures without WPG pastures served as controls. Resulting impacts on vegetation structure, livestock weight gains, bird habitat, and bird use were measured.

Year 1: This study was implemented in winter 2015-16 with heavy winter patch grazing (WPG) of research station and cooperator ranch pastures followed by grazing of all research and cooperator pastures in summer 2016.

Two events altered the trajectory of this project. The first was a severe hailstorm in July 2016 that destroyed all standing vegetation in a large area, including the pastures of one of our cooperators. Lack of sufficient vegetation growth and recovery precluded us from including that cooperator ranch in Year 2 of the study. The second event was a large wildfire in October 2016 that burned substantial portions of 4 of the 8 pastures at the Cottonwood Research Station that were included in this study.

Year 2 Cottonwood Research Station: As a result of the fire that burned substantial portions of several pastures at the Cottonwood Station, 6 of our 8 pastures were recombined into 3 pastures in Year 2; the remaining 2 pastures were maintained in their original configuration (1 WPG and 1 control). Each of the recombined pastures includes a WPG patch, a burned (PBG) patch, and a control (no burn, no winter grazing). A new patch in the remaining WPG pasture and the  WPG areas of the recombined pastures were heavily grazed in winter 2016/2017. Yearling steers grazed each of the study pastures in summer 2017. Due to extreme drought conditions in the area, grazing animals were removed from pastures in mid-July rather than the planned mid-August removal date. Data on livestock, vegetation, and wildlife attributes were collected according to protocol.

Year 2 Cooperator Pastures: One of our 2 cooperator ranches was removed from the study due to the impacts of the 2016 hailstorm. A new patch was grazed during winter 2016/2017 in the WPG pasture of the remaining cooperator ranch. Cow/calf pairs grazed the WPG and control pastures according to protocol for the entire summer (drought conditions were much less severe compared to Cottonwood). Data on livestock, vegetation, and wildlife attributes were collected according to protocol.

3) Research Conclusions: This project has resulted in several research conclusions:

1. Cattle demonstrated a significant preference for the WPG patch compared to control areas of pastures. When given the choice of grazing a WPG patch or a burned patch (as occurred in 2017), cattle preferred the burned patch. It is unlikely, however, that cattle will have opportunity to select between burned and WPG patches on producer pastures.
2. Heavy winter grazing significantly changed the structure in the WPG patches to a much shorter height; structure in burned patches was also short. Cattle grazing in summer maintained that shorter structure throughout the summer in both years for both the burned and WPG patches.
3. Cattle average daily gain (ADG) did not differ between WPG and control pastures, demonstrating that WPG does not limit livestock production.
4. Bird habitat was affected by WPG and burning, with both producing the shorter habitat preferred by a number of grassland bird species. The non-patch areas of the pastures maintained the taller structure preferred by other bird species.
5. In general, while habitat for both short-structure and tall-structure birds was available, birds did not respond to the available habitat. It is likely that scale was an issue, especially on the Cottonwood Research Station pastures. Greater bird densities and diversity was noticed on the larger producer pastures.

4) Farmer adoption actions: Adoption of new grazing strategies is typically very slow in the Northern Great Plains, however there has been continued interest in WPG as an alternative to burning, especially on public lands. For example, ranchers have contacted the US Forest Service National Grasslands staff in the region to ask them to consider WPG rather than burning to generate wildlife habitat.

Year 2 research plans:

1. A new WPG patch was created in winter 2016-17 on the remaining cooperator pastures and on the unburned WPG research station pasture. Grazing and data collection will be conducted as in Year 1.
2. The 6 remaining research station pastures were recombined to form 3 separate pastures, each having a burned patch, a 2016-17 WPG patch, and a control (not burned, not winter-grazed) area. Each of these 3 pastures will be grazed in summer 2017 by steers having access to all patches in their assigned pasture.  Data collection will be conducted as in Year 1.

Year 3 research plans:

1. Field data collection for the project is complete.
2. Data collected in Years 1 and 2 will be summarized and analyzed, and reports and manuscripts will be developed and submitted.

Year 4 research plans:

1. Field data collection for the project is complete.
2. Data collected in Years 1 and 2 have been summarized and analyzed; reports and manuscripts will be developed and submitted.

Year 5 research plans: None. Project is finished.

Attachment

Original objectives of this research are to evaluate winter-patch grazing (WPG) on 1) heterogeneity in vegetation structure/composition, 2) cattle performance, and 3) habitat and use of pastures by grassland birds. The research is occurring at 2 scales/intensities: 1) intensive, statistically rigorous data collection on small-scale research station pastures and 2) extensive data collection on production-scale pastures on 2 ranches.

A new objective of this research was added in year 2 as a result of the wildfire that burned several of the research pastures at Cottonwood. That objective is to compare WPG, patch burn grazing (PBG), and control (no burning, no winter grazing) on 1) heterogeneity in vegetation structure/composition, 2) cattle vegetation/site selection, and 3) habitat and use of pastures by grassland birds. The original objectives were maintained for the non-burned pasture pair at Cottonwood and the remaining cooperator ranch pastures.

Objectives and Performance Targets for Year 1 (2015-16) that were met include:

1. Winter-patch grazing was accomplished on a 20% patch of the 4 study pastures at the Cottonwood Research Station and the 2 producer pastures.
2. Summer grazing occurred on all study pastures.
3. All data collection was accomplished on the Cottonwood Station and one cooperator’s ranch, but was suspended on the 2^nd cooperator ranch (see below for explanation).

Objectives and Performance Targets for Year 2 (2016-17) that were met include:

1. Winter-patch grazing was accomplished on a 20% patch of the remaining original WPG pasture at Cottonwood and on the cooperator WPG pasture.
2. Six of the study pastures at Cottonwood were recombined into 3 pastures, each having a burned and non-burned area. Half of each non-burned area of each pasture was grazed heavily in winter 2016/2017 to form a WPG patch.
3. Summer grazing occurred on all study pastures. Grazing was suspended in mid-July at Cottonwood due to extreme drought conditions; grazing continued as planned at the cooperator ranch due to much milder drought conditions there.
4. All data collection was accomplished on the Cottonwood Station and the remaining cooperator ranch.

Objectives and Performance Targets for Year 3 (2017-18) that were met include:

1. Data collected on this project were summarized and analyzed.
2. An MS Thesis (Ms. Jennifer Lutze) based on the research from this project (focused on bird habitat and use) is being written.
3. Publications on vegetation structural change, livestock production, and livestock use patterns are currently in development.

Objectives and Performance Targets for Year 4 (2018-19) that were met include:

1. An MS Thesis (Ms. Jennifer Lutze) based on the research from this project (focused on bird habitat and use) is nearing completion, with an estimated publication date of January 2020.
2. Publications on vegetation structural change, livestock production, and livestock use patterns have been developed; papers have been presented at scientific meetings and manuscripts are nearing finalization for submission for publication.