The Effect of Herb Layer on Nocturnal Macrolepidoptera (Lepidoptera: Macroheterocera) Communities

Abstract Vegetation beneath the canopy might be an important factor for macromoth community composition in forest ecosystems, strongly determined by forest management practices. Herein, we compared nocturnal macrolepidoptera communities and herb layers in young and old sessile oak (Quercus petraea) dominated forest stands in the Sopron Mountains (Western Hungary). The investigation of Lepidoptera species was performed 15 times from the end of March to the end of October in 2011. Portable light traps were used, and a total of 257 species and 5503 individuals were identified. The Geometridae family was the most abundant, followed by Noctuidae and Notodontidae. To investigate vascular plant species in the herb layer, circular plots with a 10-m radius around the moth traps were used. In each plot, we estimated the abundance of plant species in 20 sub-plots with a 1-m radius from May to July of 2011. The abundance of macromoth species was higher in the old forest stand, which might be influenced by the trees’ higher foliar biomass. However, the mean abundance of herbs was lower in the old forest. Diversity of both the herb layer and the moth community were significantly higher in the young forest. However we found higher species richness of moths in the old forest. For additional analyses, moths feeding on plants in the herb layer were selected, but neither the difference in species number, neither mean abundance between the young and old forest were significant. Our results suggest that the herb layer is not a key factor for macrolepidoptera communities in Hungarian sessile oak forest stands.