Study

Grazing effects on spring ecosystem vegetation of California's hardwood rangelands

  • Published source details Allen-Diaz B. & Jackson R.D. (2000) Grazing effects on spring ecosystem vegetation of California's hardwood rangelands. Journal of Range Management, 53, 215-220.

Actions

This study is summarised as evidence for the following.

Action Category

Exclude or remove livestock from historically grazed freshwater marshes

Action Link
Marsh and Swamp Conservation

Reduce intensity of livestock grazing: freshwater marshes

Action Link
Marsh and Swamp Conservation

Other biodiversity: Use fewer grazers

Action Link
Mediterranean Farmland

Other biodiversity: Exclude grazers

Action Link
Mediterranean Farmland
  1. Exclude or remove livestock from historically grazed freshwater marshes

    A replicated, randomized, paired, controlled, before-and-after study in 1992–1997 of springs and creeks in California, USA (Allen-Diaz & Jackson 2000) found that excluding cattle typically increased herbaceous vegetation cover in creek wetlands, but had no significant effect in spring wetlands. In three of five years, ungrazed creek wetlands had higher herb cover (84–87%) than creek wetlands that remained grazed (46–59%). In the other two years, there was no significant difference between treatments (ungrazed: 46–59%; grazed: 46–59%). Before cattle exclusion, plots destined for each treatment had statistically similar herb cover (ungrazed: 59%; grazed: 46–59%). In all five years, ungrazed spring wetlands had statistically similar herb cover to grazed spring wetlands (data not reported). Methods: Nine pastures (three sets of three) were selected for the study. All contained springs and had been moderately grazed by cattle since 1960 (800–1,000 kg/ha Residual Dry Matter: the amount of herbaceous material present left after grazing). From 1992/1993, cattle were excluded from three pastures (one random pasture/set). The other pastures remained moderately or lightly grazed (1,100–3,800 kg/ha RDM). Grazing occurred in November and February–May. Vegetation cover was monitored in late May 1992–1997, along four 5–10 m transects/pasture: two in wetlands near the spring source, and two in wetlands along the resulting creek.

    (Summarised by: Nigel Taylor)

  2. Reduce intensity of livestock grazing: freshwater marshes

    A replicated, randomized, paired, controlled, before-and-after study in 1992–1997 of springs and creeks in California, USA (Allen-Diaz & Jackson 2000) found that lightly and moderately grazed areas had statistically similar herbaceous vegetation cover. This was true in five of five years, both in spring wetlands (data not reported) and in downstream wetlands alongside creeks (lightly grazed: 46–47%; heavily grazed: 35–80%). Before intervention, the creek plots had 58–80% herb cover. Methods: Three pairs of pastures were selected for the study. All contained springs and had been moderately grazed by cattle since 1960 (800–1,000 kg/ha Residual Dry Matter: the amount of herbaceous material present left after grazing). From 1992/1993, one random pasture/pair remained moderately grazed (1,100–1,800 kg/ha RDM) and one was lightly grazed (1,200–3,800 kg/ha RDM). Grazing occurred in November and February–May. Vegetation cover was monitored in late May 1992–1997, along four 5–10 m transects/pasture: two in wetlands near the spring source, and two in wetlands along the resulting creek.

    (Summarised by: Nigel Taylor)

  3. Other biodiversity: Use fewer grazers

    A replicated, randomized controlled study in 1993–1997 in grasslands in northern California, USA, found no difference in the cover of herbaceous vegetation between plots that were lightly or moderately grazed by cattle, but cover was more stable in lightly grazed plots. Plants: Similar cover of herbaceous vegetation was found in lightly-grazed and moderately-grazed plots, but cover was more stable in lightly-grazed plots (along creeks: 46–47% vs 35–80% cover; by springs: data not provided). Methods: In November and February–April 1993–1997, three pastures in each of three areas had either light grazing or moderate grazing (three replicates of each). In spring, plants were monitored at springs and alongside creeks in each pasture. The area had been grazed at moderate intensity since 1960.

     

  4. Other biodiversity: Exclude grazers

    A replicated, randomized, controlled study in 1993–1997 in grasslands in northern California, USA, found that plant community composition changed and the cover of herbaceous vegetation was higher in ungrazed plots, compared to cattle-grazed plots. Plants: Herbaceous plant cover was higher in ungrazed plots, compared to grazed plots, along creeks for three of six years (84–87% vs 46–59% cover). There were no differences in cover for plots by springs (data not provided). The plant community changed significantly in one plot with moderate grazing intensity but not in ungrazed plots (data reported as eigenvalues). Methods: From 1993 to 1997, three pastures in each of three areas were ungrazed, lightly grazed, or moderately grazed (three replicates of each). Cattle were allowed on grazed pasture in November and February–April each year. Plants were monitored at springs and along creeks in each pasture, each spring. Before the study, the area had been moderately grazed since 1960.

     

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