Summary In the past, insect diversity in grasslands showed a severe decline due to management intensification or abandonment. In this study, we investigate the long‐term influence of grazing and the potential for spatial patterns created by different grazing intensities to enhance insect diversity. In a long‐term experiment (2002–2011), three grazing intensities were applied to 1‐ha paddocks in a triplicate block design: moderate grazing (MC), lenient grazing (LC) and very lenient grazing (VLC, since 2005). The experiment was conducted in a moderately species‐rich grassland at the edge of the Solling Uplands in Lower Saxony, Germany. Orthoptera (grasshoppers) and Lepidoptera (butterflies) on three 50‐m transects per paddock were counted in 2002–2004 and again in 2010 and 2011. Statistics were performed using linear mixed modelling. Grasshopper diversity measures (species richness and abundance) were significantly affected by grazing intensity; abundance increased from 2002 to 2011 more strongly in the LC than in the MC treatment. Butterfly species richness response to grazing intensity varied among years. Data from 2010 and 2011 did not reveal any advantage of the lowest grazing intensity (VLC) compared to the intermediate grazing intensity treatment (LC) in either insect group. Multiple regressions were used to investigate diversity patterns. Along with compressed sward height, spatial patchiness was important for grasshopper species richness and abundance as well as for butterfly species numbers. Butterfly abundance was mainly influenced by vertical sward height heterogeneity in addition to the significant effects of thistle abundance and number of nectar plant species. Synthesis and applications. Cattle grazing intensity affects the proportions and spatial heterogeneity of short and tall sward patches on pastures. The less mobile grasshoppers particularly benefitted from the structural modifications created by cattle at lenient grazing levels (stocking rate 1·14 SLU ha−1, standard livestock unit (SLU) = 500 kg). In the final study years, areas with intermediate grazing intensity revealed high diversity indices and the most distinct patchiness, therefore a further reduction in grazing intensity is not recommended. This indicates that commercial livestock production may be compatible with conservation targets.

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Increasing sward phytodiversity has been suggested as having potential to increase primary production of grasslands, but whether any such gains are converted into secondary production, through improved performance of grazing livestock, remains uncertain. Animal production by cattle and sheep can also be enhanced by mixed-grazing. To our knowledge, this effect has never been studied in relation to differences in sward phytodiversity. Therefore, a rotational grazing experiment was conducted over 5 years (2007-2011) on permanent grassland in Germany using sheep and cattle in mono-(single-species) or mixed-grazing of swards differing in plant species richness. Herbicides against dicotyledonous plant species were used to create different sward types: species-poor, grass-dominated swards in contrast to untreated "diverse" control swards. We found no differences in herbage production between the sward types. However, compared to the grass-dominated sward, the diverse sward showed greater concentrations of crude protein and lower contents of acid detergent fiber in the herbage dry-matter. Lamb live weight gains were slightly greater on the diverse-swards (P < 0.05), but calf performance was unaffected by sward type. Mixed-grazing increased daily average live weight gains of suckler cows (g cow −1 d −1) (P < 0.05) as well as area-related daily live weight gains (kg ha −1 d −1) and total live weight gains (kg ha −1) during the complete grazing season (P < 0.001). This indicates advantages of combining livestock species, attributed to complementary pasture use. We suggest that mixed-grazing of cattle and sheep on phytodiverse swards is an effective and sustainable means to enhance ecological and agronomic traits such as livestock production and plant species conservation. Lamb production especially showed benefits under mixed-grazing, with a 17% increase in live weight gain. Compared to the grass-dominated sward, diverse swards resulted in an average 12% increase of live weight gains (across grazing systems and livestock species).