Interactive effects of nitrogen deposition and grazing on plant species composition in a serpentine grassland

Published source details Pasari J.R., Hernández D.L. & Zavaleta E.S. (2014) Interactive effects of nitrogen deposition and grazing on plant species composition in a serpentine grassland. Rangeland Ecology & Management (previously Journal of Range Management 1948-2004), 67, 693-700.
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This study is summarised as evidence for the following.

	Action	Category
	Other biodiversity: Exclude grazers Action Link

Other biodiversity: Exclude grazers

A replicated, randomized, controlled study in 2008–2011 in lowland grasslands in central California, USA, found smaller increases in the number of native plant species in ungrazed plots, compared to cattle-grazed plots, but found no change in the cover of native or non-native species. Plants: The number of native species declined, or increased more slowly, in ungrazed plots, compared to grazed plots (1.8 fewer to 1.0 more species vs 1.2–2.4 more species). Change in the cover of native and non-native species did not differ between ungrazed and grazed plots (native species: 8% decline to 5% increase; data not reported for non-native species). Native, non-grass species tended to be less affected by grazing than non-native grass species (results reported as principal response curves analysis). Methods: In 2008, five experimental blocks were established, each with two 5 x 5 m plots: one that excluded cattle and one that was grazed. Plants were surveyed in 0.5 x 0.5 m quadrats each spring. Before the experiment, the area had been grazed for several decades at 0.25 animal units/ha.