Suction samplers are a valuable tool to sample arthropod assemblages for conservation translocation

Abstract

An important component of recent nature conservation is the ecological restoration of semi-natural grasslands. The aim of such projects is usually the restoration of typical plant communities; translocation of animals, by contrast, plays only a minor role. This is based on the assumption that a recovery of the flora will lead to recovered fauna; however, this is not always the case. Suction samplers with gauze collection bags are well suited to sample arthropods, and they may also be helpful for transferring animals. However, to date, the suitability of suction samplers as a translocation tool is unclear due to a lack of empirical data on the mortality rate of the sampled arthropod taxa. In this study, we sampled arthropods (leafhoppers, spiders, beetles, and true bugs) with a suction sampler on 21 calcareous grasslands. Immediately after sampling, animals were stored in collection bags and their mortality rate was determined. We compared storage periods (1, 2, and 3 h) and tested the suitability of a cool box to reduce mortality rates. Our study revealed that arthropod mortality was generally low (9% of all sampled individuals); however, the survival rate was affected by (1) storage time, (2) storage conditions, and (3) arthropod group. The mortality of beetles and true bugs was very low and not influenced by storage time or storage conditions. In contrast, leafhoppers and spiders had higher mortality, which increased with storage time and decreased by the use of a cool box. According to our results, suction samplers can be a valuable tool to sample arthropod assemblages for conservation translocation. In order to reduce mortality in sensitive groups such as leafhoppers and spiders, the storage process can be optimised. We thus recommend (1) using a cool box and (2) minimising the period until release of the collected arthropods at the restored site.

Rapid response of vascular plants and insects to restoration of montane grasslands

“…We combined a sweep net (30 cm diameter) and a G-Vac suction apparatus (Stihl SH 56, Waiblingen, Germany; 12.5 cm diameter suction tube; 710 m 3 h −1 air flow rate) with a fine gauze collection bag (300 μm mesh size) on the inner side of the inlet nozzle to cover all available microhabitats and sample the complete range of herb-and ground-dwelling species (cf. Stewart, 2002;Helbing et al, 2020). We walked in loops over the whole plot and randomly performed 50 sweep net strokes and 50 suction samples.…”

“…We compared species richness, diversity and composition of grazed restoration sites and nutrient-poor pastures with long-term grazing history (target grassland). The studied insect taxa (i) play an important role both as consumers and as an abundant food source for insectivores in grassland ecosystems, (ii) occupy different ecological niches, (iii) respond quickly to habitat changes and (iv) allow standardized sampling (Kőrösi et al, 2012;Helbing et al, 2020;Fartmann et al, 2022c). With a development period of 3 to 5 years after the implemented measures, we studied the short-term effects of restoration.…”