Plant-moth community relationships at the degraded urban peat-bog in Central Europe

Abstract

Peatlands have their own, specific insect fauna. They are a habitat not only for ubiquistic but also stenotopic moths that feed on plants limited to wet, acid and oligotrophic habitats. In the past, raised bogs and fens were widely distributed in Europe. This has changed since 20th c. Due to irrigation, modern forestry, and increasing human settlement, peatlands have become isolated islands in an agricultural and urban landscape. Here, we analyze the flora in a degraded bog situated in a large Lodz city agglomeration in Poland in relation to the diversity and composition of moth fauna. Over the last 40 years since the bog has become protected as a nature reserve, birch, willow, and alder shrubs replaced the typical raised bog plant communities due to the decreased water level. The analysis of moth communities sampled in 2012 and 2013 indicates dominance of ubiquistic taxa associated with deciduous wetland forests and rushes. Tyrphobiotic and tyrphophile moth taxa were not recorded. We conclude that the absence of moths typical of bog habitats and the dominance of common, woodland species are associated with hydrological changes, the expansion of trees and brushes over typical bog plant communities, and light pollution.

Keywords: moths; nature protection; peatlands; plant communities; plant–moth interaction.

FIGURE 1

Vegetation of the “Torfowisko Rąbień” reserve and its surroundings in the 1980s (by Mamiński, 1987). 1—water; 2—drainage ditches; 3—roads; 4a —complex of communities: Eriophorum vaginatum‐Sphagnum fallax community, Eriophoro angustifolii‐Sphagnetum recurvi, Phragmition; 4b ‐ Vaccinio uliginosi‐Pinetum; 5—meadow community of Molinio‐Arrhenatheretea class; 6—Sphagno squarrosi‐Alnetum, Querco roboris‐Pinetum ; 7 ‐Spergulo vernalis‐Corynephoretum and young pine forest; 8— plant communities of fields, orchards and gardens; 9—areas with building.

FIGURE 2

Vegetation of the “Torfowisko Rąbień” reserve in 2000. 1—water; 2—drainage ditch; 3—Vaccinio uliginosi‐Pinetum ; 4a—complex of communities: Eriophorum vaginatum‐Sphagnum fallax community, Eriophoro angustifolii‐Sphagnetum recurvi, Phragmition; 4b—complex of communities: Eriophorum vaginatum‐Sphagnum fallax community, Eriophoro angustifolii‐Sphagnetum recurvi, Phragmition with Phragmites australis; 5—brushwood of trees and shurbs‐; 6a—Querco roboris‐Pinetum ; 6b—Salicetum pentandro‐cinereae.

FIGURE 3

Vegetation of the “Torfowisko Rąbień” reserve in 2018. 1 ‐ water; 2 ‐ drainage ditches; 3 ‐ Vaccinio uliginosi‐Pinetum; 4a ‐ mosaic of communities of Oxycocco‐Sphagnetea and Scheuchzerio‐Caricetea fuscae; 4b ‐ mosaic of communities of Oxycocco‐Sphagnetea and Scheuchzerio‐Caricetea fuscae with Phragmites australi s; 5 ‐ brushwood of trees and shurbs; 6a ‐ mosaic of forest communities, mainly Querco roboris‐Pinetum; 6b ‐ Salicetum pentandro‐cinereae.

FIGURE 4

Plot illustrating NMDS analysis. Similarity of caterpillar host plant preferences of moth species collected only at Różana site (R), only at Torfowa site (T), at both sites (R/T). Groups A, B, and O are marked.

FIGURE 5

Results of PCA. (a) Plot illustrating PC1 and PC2, (b) plot illustrating PC3 and PC4. Red lines and axes illustrate host plants correlated at plot (a)—with PC1, plot (b)—with PC3; blue lines and axes illustrate host plants correlated at plot (a)—with PC2, plot (b)—with PC4. Colors of moth names illustrate: green—taxa in group A associated with deciduous trees, violet—taxa in group B associated with herbs, orange—taxa in group O associated with other host plants, including coniferous trees. Plot (a) only includes color‐coded names of those correlated with PC1 and PC2, plot (b) includes only those correlated with PC3 and PC4. Taxa not corrected with PC1 and PC2, nor not correlated with PC3 and PC4 are not illustrated.