Long-Term patterns in coastal California grasslands in relation to cultivation, gophers, and grazing

Published source details Stromberg M.R. & Griffin J.R. (1996) Long-Term patterns in coastal California grasslands in relation to cultivation, gophers, and grazing. Ecological Applications, 6, 1189-1211.
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This study is summarised as evidence for the following.

	Action	Category
	Soil: Exclude grazers Action Link
	Pest regulation: Exclude grazers Action Link
	Other biodiversity: Exclude grazers Action Link

Soil: Exclude grazers

A site comparison in 1991 in annual grasslands on the Central Coast, California, USA, found less nitrogen but more phosphorus in ungrazed sites, compared to grazed sites. Nutrients: Less nitrogen was found in ungrazed sites, compared to grazed sites (0.09% vs 0.11% total Kjeldahl N), but more phosphorus was found in ungrazed sites (18 vs 11 mg P/kg soil). Methods: European domestic cattle were introduced to Monterey County in 1770. In 1937, grazers were excluded from one landscape (the Hastings Natural History Reservation), but not from an adjacent landscape. In 1991, 43 sites in the ungrazed grassland and 37 sites in the grazed grassland were sampled (methods not clearly reported, but soil samples were collected at 5–10 cm depth in a different part of this study).
Pest regulation: Exclude grazers

A site comparison in 1991 in annual grassland on the Central Coast, California, USA, found more signs of pocket gophers Thomomys bottae in ungrazed sites, compared to grazed sites. There was a correlation between gophers and plant species in grazed sites, but not in ungrazed sites. Pest damage: In grazed sites, fewer plant species were found where there were more gophers. However, in ungrazed sites, no relationship was found between gopher numbers and plant numbers (data reported as statistical results). Pest numbers: More signs of gopher activity were found in ungrazed sites, compared to grazed sites (5% vs 2% cover of soil that had been dug up). Methods: European domestic cattle were introduced to Monterey County in 1770. In 1937, grazers were excluded from one landscape (the Hastings Natural History Reservation), but not from a nearby landscape. In 1991, 43 sites in the ungrazed landscape and 37 sites in the grazed landscape were sampled (methods not clearly reported, but the cover of gopher tailings was measured in 20 x 50 cm quadrats in a different part of this study).
Other biodiversity: Exclude grazers

A site comparison in 1991 in annual grassland on the Central Coast, California, USA, found more plant species and different plant communities in ungrazed grassland, compared to grazed grassland, after over 50 years of grazer exclusion. Plants: More plant species were found in ungrazed sites, compared to grazed sites (33 vs 27 species), and there were differences in the plant communities (reported as differences in ordination space). The invasive, non-native medusahead grass Elymus (Taeniatherum) caput-medusae was found only in grazed sites, but the native grass Elymus glaucus was found only in ungrazed sites (see publication for details of other species). Implementation options: When split into cultivated or uncultivated sites, more plant species were found in historically cultivated sites that were ungrazed, compared to grazed (32 vs 24 species), but similar numbers of plant species were found in uncultivated sites that were ungrazed or grazed (33 vs 30). Methods: European domestic cattle were introduced to Monterey County in 1770. In 1937, grazers were excluded from one landscape (the Hastings Natural History Reservation), but not from a nearby landscape. In 1991, 43 sites in the ungrazed landscape and 37 sites in the grazed landscape were sampled (methods not clearly reported, but plant cover was measured in 20 x 50 m plots in April–May in a different part of this study).