Effects of different mowing regimes on orthopterans of Central-European mesic hay meadows

Abstract

Method, frequency and date of mowing influence the presence and population size of Orthoptera species, which show strong dependence on the vertical structure of grasslands. Responses of orthopteran assemblages to the effects of various mowing regimes applied to different parts of the same habitat are still not fully understood. In this study, we asked how different mowing regimes (mowing in May; mowing in September; mowing in May and September; abandonment of mowing) influence species richness, Shannon diversity and density of local orthopteran assemblages on a small spatial scale in Central European mesic hay meadows. Furthermore, the study aimed to determine the type of meadow management that is most suitable for preserving local orthopteran assemblages. The date of mowing had no significant overall effect on species richness, density or diversity of grasshoppers. However, grasshopper species richness and Shannon diversity were reduced immediately after mowing (in June sampling of sites mown in May), and rose later in the season. Grasshopper density was low on abandoned sites which were not mowed in the last ten years and there was a negative correlation between orthopteran density and vegetation height. Nymphs, on the other hand, showed elevated density just after mowing which was reduced later in the season. Life forms of the orthopteran assemblages showed dominance of pratinicol species. Silvicol species were found only in abandoned habitats, while arbusticol species were found only on abandoned patches and patches mown in September. Results showed that the long-term preservation of natural orthopteran assemblages in mesic hay meadows would benefit from landuse practices which are diversified spatially and temporally, as practiced in traditional extensive management regimes.

Land-use intensity and landscape structure drive the acoustic composition of grasslands

“…In their study, a direct effect of mowing regime on herbivore diversity was found, but dependent on how long after mowing the herbivore sampling was undertaken. This might suggest that 29 herbivores re-enter previously mowed plots, as observed for example by Humbert et al (2012) and Kenyeres and Szentirmai (2017), creating potential sinks for surrounding populations.…”

The effects of grazing and mowing on large marsh grasshopper, Stethophyma grossum (Orthoptera: Acrididae), populations in Western Europe: a review

“…This was sometimes combined with cutting for hay, with one early cut followed by grazing of the remnant sward. Alternatively, on some sites, hay cutting was carried out once or twice a year, typically in May-June and/or August-September (Grootjans andVerbeek 2002, Kenyeres andSzentirmai 2017).…”

“…If a late summer cut is required, this should be after mid-September when most of the egg-laying is complete. In order to minimize mortality of grasshoppers (and other invertebrates), the use of a bar mower (rather than a rotary or flail mower) set to a minimum height of 10 cm is recommended (Humbert et al 2009, Kenyeres andSzentirmai 2017). Malkus (1997) also makes further recommendations to reduce mortality of S. grossum during mowing: mowing should only take place in warm, sunny weather, to allow grasshoppers to escape; retain the hay on the surface for a few days following the cut, again to allow grasshoppers to escape; and unmown areas should be retained close to the mown area, to provide a refuge.…”

“…Grazing and mowing exert important influences on vegetation structure and are therefore key factors affecting grasshopper populations (Clarke 1948, Gardiner et al 2002, Humbert et al 2009, Kenyeres and Szentirmai 2017. Rare and localized species, such as the large marsh grasshopper, Stethophyma grossum L. (Orthoptera: Acrididae), have very specific micro-habitat requirements which can be influenced by grazing and mowing.…”

Management is more important than urban landscape parameters in shaping orthopteran assemblages across green infrastructure in a metropole

“…Orthoptera in general are known to respond significantly to intensified management, which is associated with decreases in species richness and abundance (Batáry et al 2007;Braschler et al 2009;Marini et al 2009;Humbert et al 2012), although not all studies confirmed a decline in abundance (Chisté et al 2016). At the same time, completely refraining from management measures can cause declines in species richness and abundance as well (Kolshorn and Greven 1995;Kenyeres and Szentirmai 2017). Moreover, detrimental effects of habitat fragmentation and isolation on orthopteran abundances were reported (Herrmann 1995;Sachteleben et al 2007;Cherrill 2010;Zulka et al 2014).…”