Graze with livestock after seeding/planting
Overall effectiveness category Evidence not assessed
Number of studies: 7
Background information and definitions
Grazing with livestock may reduce vegetation height, and disturb soil and vegetation, due to trampling. This may result in small-scale differences in the suitability of grassland habitat to different plant species, and as a result increase species diversity. Sowing seeds may further increase the probability of grassland species establishing successfully.
The studies detailed in this intervention are direct tests of the effectiveness of grazing with livestock after seeding or planting (e.g. by comparison with an ungrazed but seeded or planted plot). Studies that represent comparisons of seeding to unseeded plots can be found in the actions ‘Sow grass seeds’, ‘Sow grassland forb species’ or ‘Sow native grass and forbs’.
Supporting evidence from individual studies
A replicated, randomized, controlled study in 1987–1988 in a grassland in Oxfordshire, UK (Silvertown et al. 1992) found that allowing grazing in the winter after sowing of cut-leaved cranesbill Geranium dissectum seeds resulted in higher seedling survival than in areas that were not grazed but where seeds were sown. Fourteen months after sowing, the percentage of surviving seedlings was higher in plots that were grazed in winter and sown with cut-leaved cranesbill seeds (9%) than in plots that were not grazed but where seeds were sown (2%). Four 50 x 50 m paddocks were grazed in winter while four paddocks were not grazed. In June 1987, three 25 x 25 cm quadrats in each paddock were sown with 121 cut-leaved cranesbill seeds. The number of seedlings in the quadrats was counted in October 1987 and March and August 1988.Study and other actions tested
A replicated, controlled study in 1986–1992 in a former opencast mine in Northumberland, UK (Chapman & Younger 1995) found that grazing with livestock after sowing seeds reduced plant species richness compared to cutting vegetation after sowing. After one year, plant species richness did not differ significantly between plots sown with seeds and grazed by livestock in summer (21 species/m2) and plots sown with seeds and cut once/year (20 species/m2). However, after two years, species richness was lower in plots that were grazed by livestock each summer and this remained the case for the following two years (seeded and grazed: 20–21 species/m2; seeded and cut: 22–23 species/m2). In 1986, topsoil that had been removed during mining was spread over the site and sown with a temporary cover crop. The cover crop was removed by ploughing in autumn 1987 and soil was disturbed using a power harrow in April 1988. Two 1,500-m2 plots were fenced and grazed by livestock throughout the summer, while two plots were cut every year in mid-July. All plots were grazed in spring. In July 1989–1992, vegetation cover for each species was estimated using fifteen 1-m2 quadrats in each plot.Study and other actions tested
A replicated study in 1993–1999 in an ex-arable field near Aberdeen, Scotland, UK (Warren et al. 2002) found that grazing with cattle after sowing grass and forb seeds led to a greater number, but lower cover, of sown species compared to grazing with sheep. After six years, plots that were grazed with cattle after seeds were sown had on average more sown species (4.8 species/m²) than plots grazed by sheep after seeds were sown (2.2 species/m²). However, cattle-grazed plots had lower sown species cover (46%) than sheep-grazed plots (91%). In April–May 1993, four 20 x 40 m fenced plots were ploughed and sown with a native seed mix (four grass and 10 forb species sown at a rate of 20 kg/ha). Each year in 1994–1999, two plots were grazed by cattle in May–October, and two plots were grazed by sheep in April–October. Vegetation was monitored annually within twenty 1-m2 quadrats (number of sown species) and ten 0.25-m2 quadrats (cover of sown species) randomly placed in each plot in June 1994–1999.Study and other actions tested
A replicated, randomized, controlled study in 1998–1999 in grazed grasslands in Manawatu, New Zealand (Edwards et al. 2005) found that grazing with sheep continuously after sowing seeds did not alter the species richness of sown plants but increased the cover of four of eight sown plant species compared to grazing on rotation. After 21 months, sown species richness did not differ significantly in plots that were grazed continuously (8.5 species/4 m2) or grazed on rotation (7.5–8.8 species/4 m2). Average cover of four of eight sown plant species was higher in plots that were grazed continuously than in those grazed on rotation: spear thistle Cirsium vulgare (continuous: 9%; rotation: 3–4%); ribwort plantain Plantago lanceolata (continuous: 7%; rotation: 1–2%); bitter dock Rumex obtusifolius (continuous: 7%; rotation: 1–3%); white clover Trifolium repens (continuous: 21%; rotation: 14–16%). Cover of perennial ryegrass Lolium perenne did not differ significantly between plots that were grazed continuously (74%) or on rotation (81–84%). Three other species (greater bird’s foot trefoil Lotus uliginosus, Dallis grass Paspalum dilatatum, creeping thistle Cirsium arvense) had few or no seedlings in any plots. In March 1998, seeds of eight plant species were sown in ten 36 x 24 m plots. Sheep grazed continuously all year round in two plots, while in the other eight plots grazing was rotated at intervals of 12–63 days. In December 1999, plant cover and species richness were estimated in twenty-four 2 x 2 m quadrats placed in each plot.Study and other actions tested
A replicated, randomized, paired, controlled study in 2001–2010 in a calcareous grassland previously affected by shrubland encroachment in Tuscany, Italy (Maccherini & Santi 2012) found that grazing with livestock after sowing of locally sourced seeds increased plant species richness compared to sowing without grazing. Nine years after sowing and the start of grazing, plots that were seeded and grazed had on average higher plant species richness (39 species/plot) than plots that were seeded but not grazed (31 species/plot). In 1999, shrubs were removed from the entire site, and in spring 2001, blackthorn Prunus spinosa plants were cut. In October 2001, four 5 × 3 m plots were sown with locally collected seeds at a rate of 4 g/m2 and subsequently grazed by livestock. Four plots were sown with seeds and fenced to exclude livestock. In June/July 2001–2010, sixteen 2 x 1 m quadrats were placed in each plot and a point quadrat method used to estimate cover of each plant species.Study and other actions tested
A replicated, controlled study in 2012–2013 in a serpentine grassland in California, USA (Funk et al. 2015) found that grazing with cattle after sowing grass seeds led to a greater number, but lower cover, of native plant species compared to not grazing after sowing. Plots grazed with cattle after sowing seeds had on average more native plant species (10 species/plot) than plots not grazed after sowing (9 species/plot). However, grazed plots had lower native plant species cover (63%) than ungrazed plots (77%). The cover of non-native invasive species did not differ significantly between grazed (20%) and ungrazed plots (29%). In November 2012, twenty 1 x 1 m irrigated plots were sown with seeds of three native grass species. Half of the plots were grazed by cattle (0.25 cow-calf pairs/ha) from November 2012 to May 2013, while the other half were fenced and not grazed. Vegetation cover was estimated in March and April 2013 using a 0.25 × 0.25 m quadrat placed in each plot.Study and other actions tested
A replicated, controlled study in 2013–2015 at eight species-poor grassland sites in east Hungary (Valkó et al. 2016) found that grazing with livestock after sowing seeds did not alter the cover of target plants or weeds compared to not grazing after sowing. During the first two years after sowing, there was no significant difference in the average cover of sown target plant species or weed species between plots that were grazed by cattle (target species: 52–59%; weed species: 23–31%) and plots left ungrazed (target species: 51–66%; weed species: 19%). In October 2013, two 4 x 4 m plots located >50 m apart were established in each of eight sites. All plots were prepared (by digging, rotary hoeing and raking the soil) and sown with a seed mixture of 35 native grassland species at a rate of 10 g/m2. One plot/site was grazed by cattle (0.5 livestock units/ha) in April–October each year, the other was fenced and left ungrazed. Vegetation cover was recorded in each of the 16 plots in June 2014 and 2015.Study and other actions tested