Data from: Massive structural redundancies in species composition patterns of floodplain forest moths

Truxa, Christine, University of Vienna

Fiedler, Konrad, University of Vienna

Published Apr 27, 2015 on Dryad. https://doi.org/10.5061/dryad.fg8f6

Cite this dataset

Truxa, Christine; Fiedler, Konrad (2015). Data from: Massive structural redundancies in species composition patterns of floodplain forest moths [Dataset]. Dryad. https://doi.org/10.5061/dryad.fg8f6

Abstract

Terrestrial arthropod communities usually consist of very large species numbers. Data from experiments or long time-series would be required to ascertain the functional significance of individual species. Both are largely unavailable for species-rich natural communities. Recognising structural redundancies in species composition allows for an alternative approach to address how strong functional redundancy might be in natural assemblages, if structural and functional redundancies are related to each other. Determining structural redundancies is a regular topic in aquatic ecology, but has rarely been applied to terrestrial communities. We explored the extent of structural redundancy in species-rich terrestrial insect assemblages and whether structural redundancies are contingent to species abundances or functional group affiliations. We used the BVSTEP algorithm to determine structural redundancies in a large data set of moth species (32 181 individuals; 448 species) that had been sampled with light-traps in three different floodplain forests in eastern Austria. We partitioned the moth species into 12 functional types based on larval host-plant affiliations to test if moth species included in reduced subsets represent functional groups in the same proportions as they occur in the entire fauna. We observed far more massive structural redundancies in moth assemblages than previously found in aquatic communities. Subsets containing only 8–15 species (1.8–3.3% of all recorded species) were still highly representative for the overall data. Subsets selected by the BVSTEP procedure performed better than equally small subsets that were defined solely by species abundances or by functional group affiliations. Effective ‘surrogate’ subsets contained only 6–9 of the 12 functional moth types. High abundance only loosely corresponded with the frequency at which a moth species was included in the subsets. Thus, certain uncommon species contribute importantly to species composition patterns. Our results show unexpectedly extensive structural redundancies in complex floodplain forest moth communities, which may also indicate strong functional redundancies.

Usage notes

Classification of moth species into 12 functional groups according to larval feeding relationships.

Moths have been sampled in three floodplain forest regions in eastern Austria (along the rivers Danube, Morava and Leitha) which differ in flood regimes and forest vegetation. Each region contained two classes of forest habitats: ones that are regularly inundated once a year, and others that are not or only rarely flooded. In each forest habitat five light trap sites were selected at a distance of about 100 m from each other to avoid interference between traps. In the Leitha floodplain only four light traps were used because of the small size of remaining forest fragments. Automatic low-power light traps, each equipped with two 15 W lamps (Sylvania Blacklight-Blue, F15W/BLB-T8; and Philips TLD, 15W/05) and powered by a 12V car battery were placed about 1 m above ground under a closed forest canopy and run once a month during the vegetation period (March to November) at each of the 28 sites. Light traps within one habitat were operated simultaneously. At dusk the light was automatically switched on and run for about 6 hours. All 6 forest habitats were sampled on consecutive days, or as soon as possible if spells of unfavourable weather had to be avoided. Traps were never run during the 5 days before and after full moon to avoid any negative impact of moonlight on trap catches. Sampling did not take place during rainy weather, in which cases sampling was postponed until conditions improved, i.e. sampling was carried out on the next possible night with better weather conditions. Altogether, sampling was conducted over two complete annual cycles on 103 nights between 20.VIII.2006 and 24.VIII.2008. The sampling season ended with the first incidence of frost in autumn (last sampling dates: 26.XI.2006 and 08.XI.2007) and started again at spring time (first sampling dates: 26.III.2007 and 07.IV.2008). In all, data from 442 nightly trap samples were analysed. The number of moths caught during a single trap night ranged from 0 to 1092 (site MF5, 08.VIII.2007) individuals. Eighteen nightly trap samples did not contain any moths, likely due to cold temperatures and generally low moth activity in March, April, October and November. Three further samples did not contain moths due to equipment failure. Further information: Truxa, C. 2012. Community ecology of moths in floodplain forests of Eastern Austria. Doctoral dissertation, University of Vienna. URL: http://othes.univie.ac.at/25605/

Appendix_3.xlsx

Location

Gerhaus

Marchegg

River Morava

Königshof

flooded habitat: N 16°42'20"; E 48°00'19"

non-flooded habitat: N 16°41'24"

E 48°08'41"; flooded habitat: N 16°41'02"

E 48°17'96"

E 48°07'53"

Orth an der Donau

Eastern Austria

River Danube

non-flooded habitat: N 16°51'32"; E 48°03'28"

non-flooded habitat: 16°53'26"; E 48°17'00"; flooded habitat: N 16°53'22"

River Leitha