Theme 7: Capacity--Oral Sessions

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Decisions on how to move livestock in space and time are central to rangeland management. Despite decades of small-scale research, substantial uncertainty exists regarding the relative importance of cattle stocking rates per se, versus the movement of cattle in both space and time, in achieving desired vegetation and livestock outcomes at scales relevant to livestock producers. We report on a ranch-scale experiment comparing effects of collaborative, adaptive, multi-paddock, rotational management (CARM) versus more traditional, season-long, continuous rangeland management (TRM) on perennial grass density and production, cattle performance, and wildlife habitat, while holding the annual stocking rate the same in both systems. We collaborated with stakeholders to develop an adaptive grazing management plan, collected pre-treatment data in 2013, and implemented treatments during 2014 – 2020. Results for 2014 – 2018 were reported by Augustine et al. (2020); here we report on two additional years of results, covering a 7-year period of treatments from 2014 – 2020. With two additional years of measurements, we found no significant difference in total forage production in CARM vs. TRM treatments, averaged across all soil types in the experiment. In one year, we found that CARM increased forage production on loamy soils and decreased forage production on alkaline soils, but these differences were minor and in opposite directions, resulting in no net overall effect. Furthermore, we found that adaptive, rotational grazing management substantially reduced livestock weight gains in each of the first 6 years of the experiment, when cattle were managed as a single, large herd occupying each paddock sequentially. Across the 6 years, cattle weight gain averaged 15% lower in CARM vs. TRM. In the 7th year, stocking density in CARM was reduced 50% by giving cattle access to two paddocks at a time. This year also coincided with a drought. Under these conditions, cattle weight gains were identical in both treatments. Results emphasize the importance of replicated controls in assessing grazing management effects. Even in heterogeneous landscapes where livestock are moved adaptively among paddocks to match seasonal patterns of forage growth, such management may not lead to desired outcomes for vegetation and livestock.

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Adaptive, Multi-Paddock, Rotational Grazing Management: An Experimental, Ranch-Scale Assessment of Effects on Multiple Ecosystem Services

Decisions on how to move livestock in space and time are central to rangeland management. Despite decades of small-scale research, substantial uncertainty exists regarding the relative importance of cattle stocking rates per se, versus the movement of cattle in both space and time, in achieving desired vegetation and livestock outcomes at scales relevant to livestock producers. We report on a ranch-scale experiment comparing effects of collaborative, adaptive, multi-paddock, rotational management (CARM) versus more traditional, season-long, continuous rangeland management (TRM) on perennial grass density and production, cattle performance, and wildlife habitat, while holding the annual stocking rate the same in both systems. We collaborated with stakeholders to develop an adaptive grazing management plan, collected pre-treatment data in 2013, and implemented treatments during 2014 – 2020. Results for 2014 – 2018 were reported by Augustine et al. (2020); here we report on two additional years of results, covering a 7-year period of treatments from 2014 – 2020. With two additional years of measurements, we found no significant difference in total forage production in CARM vs. TRM treatments, averaged across all soil types in the experiment. In one year, we found that CARM increased forage production on loamy soils and decreased forage production on alkaline soils, but these differences were minor and in opposite directions, resulting in no net overall effect. Furthermore, we found that adaptive, rotational grazing management substantially reduced livestock weight gains in each of the first 6 years of the experiment, when cattle were managed as a single, large herd occupying each paddock sequentially. Across the 6 years, cattle weight gain averaged 15% lower in CARM vs. TRM. In the 7th year, stocking density in CARM was reduced 50% by giving cattle access to two paddocks at a time. This year also coincided with a drought. Under these conditions, cattle weight gains were identical in both treatments. Results emphasize the importance of replicated controls in assessing grazing management effects. Even in heterogeneous landscapes where livestock are moved adaptively among paddocks to match seasonal patterns of forage growth, such management may not lead to desired outcomes for vegetation and livestock.