Individual study: Loss of biodiversity and hydrologic function in seasonal wetlands persists over 10 years of livestock grazing removal
Marty J.T. (2015) Loss of biodiversity and hydrologic function in seasonal wetlands persists over 10 years of livestock grazing removal. Restoration Ecology, 23, 548-554
This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.
Water: Exclude grazers
A replicated, randomized, controlled study in 2002–2010 in central California, USA (same study as (2)), found that pools in plots from which cattle were excluded were shallower and wet for less time than those in grazed plots. Water availability: Pools were shallower in ungrazed plots, compared to grazed plots (8 vs 12 cm maximum depth), and were wet for fewer days each year (16–178 vs 41–192 wet days/year). Differences were more pronounced in drier years. Methods: Eighteen plots were established in 2000, each with three pools (70–1,130 m2) and nine times more dry land than pool. Areas were grazed continuously or seasonally (dry: October–November; wet: April–June). Before the experiment, the area had been grazed for at least 100 years. Pools were monitored in 2002–2010.
Other biodiversity: Exclude grazers
A replicated, randomized, controlled, before-and-after study in 2000–2010 in grasslands and wetlands in central California, USA (same study as (21)), found fewer species and lower cover of native plants in plots with cattle excluded, compared to grazed plots. Community composition differed, and biomass at the end of the summer was higher, in ungrazed plots, in some comparisons. Plants: Fewer native plant species were found in ungrazed plots, compared to cattle-grazed plots, in all but the first year of the experiment (6–8 vs 7–9 species/sample). Cover of native plant species was lower in ungrazed plots, compared to cattle grazed plots (32–61% vs 50–67%). This effect was stronger at pool edges than within pools or on dry land (lower native cover in four of 10 years for edges vs two of 10 years for other habitats). Ungrazed plots were more dominated by grasses in five of 10 years (0.7–4.6 vs 0.3–0.8 times more grass than non-grass cover). Ungrazed plots had higher plant biomass at the end of the grazing season, compared to grazed plots, in seven of 10 years (2,100–4,000 vs 860–2,200 kg dry mass/ha). Methods: Twenty-four plots were established in 2000, each with three pools (70–1,130 m2) and nine times more dry land than pool area. In 2000–2003, cattle were excluded from six pools, six were grazed continuously from October to June, and 12 were grazed seasonally (either October–January or April–June). In 2003, the seasonal grazing experiment was stopped and only ungrazed and continuously grazed plots were continued. Plants were monitored in April–May each year within pools, at pool edges, and on dry land. The area had been grazed for at least 100 years before the start of the experiment.