Responses of Grassland Invertebrates to Management by Cutting. III. Adverse Effects on Auchenorhyncha

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Abstract
The responses of Auchenorhyncha to management by cutting of calcareous, Arrhenatherum-dominated grassland were examined in a field experiment. Four replicates of each of 4 cutting treatments, in May (M), July (J), both May and July (B), and Control (C) (uncut), were sampled regularly with a vacuum net for 3 yr (1973-1975). Twenty-three species showed a significant difference in their abundance between treatments, though not all were consistent in time. The method of analysis (Turkey''s T) allowed multiple comparisons to be made. Cutting in May reduced adult populations of few Auchenorhyncha, single-brooded species with an early summer emergence of adults being most affected. Most species were not significantly reduced on the May-cut plots compared with the controls, but some effects were observed on the most abundant species. The July cut severely reduced numbers of most species. Differences between the effects of the single July cut and cutting in both May and July were few, but when they did occur the combination cut reduced numbers more. The effects recorded clearly grouped the treatments into the 2 pairs M + C and J + B for most species. Effects of the May cut were generally short-lived. Those of the July cut persisted, often through the winter into spring. Most of the species which overwintered as adults were affected during the winter by the previous summer''s cut. Progressive declines were recorded in many species from 1973-1975. Although these occurred particularly on the plots cut in July, populations of some species also declined on the uncut grasslands. Possible reasons for this are suggested. The interaction of the timing of treatment with the phenology of Auchenorhyncha explains many of the findings. Most species become adult in late summer (July-Sept.) and are particularly affected by cutting in July. Stratification of species in tall grass is an important factor in determining the fauna of grasslands. The findings support earlier recommendations for the management of grassland nature reserves, but the positive responses of other species of Auchenorhyncha to cutting need also to be considered.