Immediate and long-term facilitative effects of cattle grazing on a polyphagous caterpillar

Published source details Berman T.S., Ben-Ari M., Henkin Z. & Inbar M. (2018) Immediate and long-term facilitative effects of cattle grazing on a polyphagous caterpillar. Agriculture, Ecosystems & Environment, 261, 45-53.
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This study is summarised as evidence for the following.

	Action	Category
	Increase grazing intensity or cutting frequency on grassland Action Link
	Rear declining species in captivity Action Link
	Cease grazing on grassland to allow early succession Action Link

Increase grazing intensity or cutting frequency on grassland

A replicated, paired, site comparison study in 2014–2015 on a farm in Galilee, Israel (Berman et al. 2018) found that heavily grazed paddocks had fewer spring webworm Ocnogyna loewii caterpillar nests than moderately grazed paddocks, but grazed paddocks had more nests and solitary individuals than ungrazed paddocks. After 20 years of grazing, the number of caterpillar nests in heavily grazed paddocks (transects: 2.8; plots: 2.1–8.5 nests) was lower than in moderately grazed paddocks (transects: 10.0; plots: 7.1–14.1 nests), but higher than in ungrazed paddocks (transects: 1.1; plots: 0.5–6.1 nests). The number of older, solitary caterpillars was higher in heavily (transects: 23.5–77.0; plots: 2.7 individuals) or moderately (transects: 32.3–36.5; plots: 3.0 individuals) grazed paddocks than in ungrazed paddocks (transects: 6.4–14.2; plots: 1.5 individuals). From 1994, a 1,450-ha farm was divided into paddocks managed permanently by heavy (1.1 cows/ha) or moderate (0.55 cows/ha) grazing, or left ungrazed. In January 2015 and March 2014–2015, caterpillar nests (January) and individuals (March) were counted once/year on three 20-m-long transects in each of two heavily grazed and two moderately grazed paddocks (~27 ha) and in four ungrazed paddocks (0.5–4 ha). Within each of the four grazed paddocks, cattle were excluded from five fenced, 10 × 10 m plots for >10 years. In January 2014–2015, all caterpillar nests were counted in each fenced, ungrazed plot and a paired, grazed plot 3 m away in the surrounding paddock. In March 2015, individual caterpillars were counted in three 30 × 30 cm sub-plots in each grazed and ungrazed plot.

(Summarised by: Andrew Bladon)
Rear declining species in captivity

A replicated, randomized, controlled study in 2014–2015 on a farm in Galilee, Israel (Berman et al. 2018) found that captive spring webworm Ocnogyna loewii caterpillars fed vegetation from grazed paddocks had a similar growth rate to caterpillars fed vegetation from ungrazed paddocks. Over five days, the growth rate of caterpillars fed on vegetation from cattle-grazed paddocks (0.12 mg/mg/day) was similar to caterpillars fed vegetation from ungrazed pastures (0.11 mg/mg/day). Sixty wild, fourth instar caterpillars were collected and weighed, and placed in individual plastic containers (12 cm diameter, 8 cm height) with a perforated lid. Caterpillars were randomly divided into six groups, and fed daily with fresh plants from one of six paddocks (three grazed, three ungrazed). Caterpillars were re-weighed after five days, and their growth rate calculated.

(Summarised by: Andrew Bladon)
Cease grazing on grassland to allow early succession

A replicated, paired, site comparison study and a replicated, paired, controlled, before-and-after study in 2014–2015 on a farm in Galilee, Israel (Berman et al. 2018) found that ungrazed paddocks had fewer spring webworm Ocnogyna loewii caterpillar nests and solitary caterpillars than grazed paddocks. After 10–20 years of abandonment, the number of caterpillar nests and older, solitary caterpillars in ungrazed paddocks (nests: 1; individuals: 6–14) and plots (nests: 1–6; individuals: 1–2) was lower than in grazed paddocks (nests: 3–10; individuals: 24–77) and plots (nests: 2–14; individuals: 3). In addition, after two weeks of grazing exclusion, there were fewer caterpillar nests in recently fenced areas (5–21 individuals) than in unfenced, grazed areas (13–31 individuals), despite having similar numbers before fencing was installed (fenced: 16–19; unfenced: 18–20 individuals). From 1994, a 1,450-ha farm was divided into paddocks managed permanently by moderate (0.55 cows/ha) or heavy (1.1 cows/ha) grazing, or left ungrazed. In January 2015 and March 2014–2015, caterpillar nests (January) and individuals (March) were counted once/year on three 20-m-long transects in each of four ungrazed paddocks (0.5–4 ha) and four grazed paddocks (~27 ha). Within each of the four grazed paddocks, cattle were excluded from five fenced, 10 × 10 m plots for >10 years. In January 2014–2015, all caterpillar nests were counted in each fenced, ungrazed plot and a paired, grazed plot 3 m away in the surrounding paddock. In March 2015, individual caterpillars were counted in three 30 × 30 cm sub-plots in each grazed and ungrazed plot. In January 2014 and 2015, seven and six fenced plots (6 × 6 m, 12 m apart) were constructed within a 50-ha, heavily grazed paddock to exclude cattle. From January 2014 and 2015, caterpillar nests were counted weekly in each ungrazed, fenced plot and a paired, grazed plot 3 m away.

(Summarised by: Andrew Bladon)