Diversity and trait composition of moths respond to land-use intensification in grasslands: Generalists replace specialists

Published source details Mangels J., Fiedler K., Schneider F.D. & Bluthgen N. (2017) Diversity and trait composition of moths respond to land-use intensification in grasslands: Generalists replace specialists. Biodiversity and Conservation, 26, 3385-3405.
Share Tweet Email

Actions

This study is summarised as evidence for the following.

	Action	Category
	Reduce cutting frequency on grassland Action Link
	Reduce fertilizer, pesticide or herbicide use generally Action Link
	Reduce management intensity on permanent grasslands (several interventions at once) Action Link
	Reduce grazing intensity on grassland by reducing stocking density Action Link
	Maintain species-rich, semi-natural grassland Action Link

Reduce cutting frequency on grassland

A replicated, site comparison study in 2014 in 26 grasslands in Germany (Mangels et al. 2017) reported that grasslands managed with reduced cutting frequency (sometimes also grazed) supported more moth species than more frequently mown grasslands. Results were not tested for statistical significance. Grasslands managed with less frequent cutting had more moth species (99 species) than grasslands managed with more frequent cutting (79 species). From 2006, across three regions, nine grasslands were managed by mowing (often with nitrogen fertilization) at low (0–1 cuts/year) or high frequency (2 cuts/year), nine were managed by grazing (by cattle, sheep or horses at 26–520 livestock units/ha/year), and eight were mown and grazed (1–2 cuts/year; 76–163 livestock units/ha/year). Moths were collected once/month from nine grasslands in each of two regions (May–August 2014), and from eight grasslands in one region (June–July 2014). Each night, a 12 V actinic and black-light trap were placed in the centre of each of three grasslands for 138–317 minutes/night.

(Summarised by: Andrew Bladon)
Reduce fertilizer, pesticide or herbicide use generally

A replicated, site comparison study in 2014 in 26 grasslands in Germany (Mangels et al. 2017) found that unfertilized grasslands had a similar abundance, species richness and diversity of moths to fertilized grasslands. Unfertilized grasslands had a similar abundance, species richness and diversity of moths to fertilized grasslands (data presented as model results). However, unfertilized grasslands did support more specialist moth species than fertilized grasslands (data presented as model results). Of 58 individual species monitored, seven preferred unfertilized or lightly fertilized grasslands, and 12 preferred more heavily fertilized grasslands (see paper for individual species data). From 2006, across three regions, eleven grasslands were fertilized with 1–138 kg nitrogen/ha, and 15 were unfertilized. Moths were collected once/month from nine grasslands in each of two regions (May–August 2014), and from eight grasslands in one region (June–July 2014). Each night, a 12 V actinic and black-light trap were placed in the centre of each of three grasslands for 138–317 minutes/night. Moths were classified as specialists based on the number of food plants eaten by their caterpillars.

(Summarised by: Andrew Bladon)
Reduce management intensity on permanent grasslands (several interventions at once)

A replicated, site comparison study in 2014 in 26 grasslands in Germany (Mangels et al. 2017) found that grasslands managed less intensively had a similar abundance, species richness and diversity of moths to more intensively managed grasslands. The abundance, species richness and diversity of moths on grasslands managed with lower grazing intensity, less frequent cutting and/or less fertilizer input was similar to more intensively managed grasslands (data presented as model results). However, less intensively managed grasslands did support more specialist moth species, and species of greater conservation concern, than more intensively managed grasslands (data presented as model results). Of 87 individual species monitored, 24 species preferred less intensively managed grasslands, and 12 preferred more intensively managed grasslands (see paper for individual species data). From 2006, across three regions, nine grasslands were managed by grazing (by cattle, sheep or horses at 26–520 livestock units/ha/year), nine by mowing (1–2 cuts/year, often with nitrogen fertilization), and eight were grazed and mown (76–163 livestock units/ha/year; 1–2 cuts/year). Eleven of the mown or mown and grazed grasslands were fertilized with 1–138 kg nitrogen/ha. Moths were collected once/month from nine grasslands in each of two regions (May–August 2014), and from eight grasslands in one region (June–July 2014). Each night, a 12 V actinic and black-light trap were placed in the centre of each of three grasslands for 138–317 minutes/night. Moths were classified as specialists based on the number of food plants eaten by their caterpillars.

(Summarised by: Andrew Bladon)
Reduce grazing intensity on grassland by reducing stocking density

A replicated, site comparison study in 2014 in 26 grasslands in Germany (Mangels et al. 2017) reported that grasslands managed with lower stocking density (sometimes also mown) supported more moth species than grasslands grazed at higher stocking density. Results were not tested for statistical significance. Grasslands managed with a lower stocking density had more moth species (143 species) than grasslands managed with a higher stocking density (35 species). From 2006, across three regions, nine grasslands were managed by grazing (by cattle, sheep or horses) at low (0–113 livestock units/ha/year) or high density (113–520 livestock units/ha/year), nine were managed by mowing (1–2 cuts/year, often with nitrogen fertilization), and eight were grazed and mown (76–163 livestock units/ha/year; 1–2 cuts/year). Moths were collected once/month from nine grasslands in each of two regions (May–August 2014), and from eight grasslands in one region (June–July 2014). Each night, a 12 V actinic and black-light trap were placed in the centre of each of three grasslands for 138–317 minutes/night.

(Summarised by: Andrew Bladon)
Maintain species-rich, semi-natural grassland

A replicated, site comparison study in 2014 in 26 grasslands in Germany (Mangels et al. 2017) found that grasslands managed by mowing (sometimes alongside grazing) had a lower abundance, species richness and diversity of moths than unmown, grazed grasslands, but grasslands managed by grazing (sometimes alongside mowing) had a similar abundance, species richness and diversity of moths to ungrazed, mown grasslands. Mown grasslands had a lower abundance, species richness and diversity of moths, and more generalist and widespread species, than unmown, grazed grasslands (data presented as model results). Grazed grasslands had a similar abundance, species richness and diversity of moths to ungrazed, mown grasslands (data presented as model results). In addition, grazed and mown grasslands were inhabited by different moth communities (see paper for details). Of 87 individual species monitored, 10 species preferred mown grasslands and 19 species avoided mown grasslands, while 12 species preferred grazed grasslands and 24 species avoided grazed grasslands (see paper for individual species data). From 2006, across three regions, nine grasslands were managed by grazing (by cattle, sheep or horses at 26–520 livestock units/ha/year), nine by mowing (1–2 cuts/year, often with nitrogen fertilization), and eight were grazed and mown (76–163 livestock units/ha/year; 1–2 cuts/year). Moths were collected once/month from nine grasslands in each of two regions (May–August 2014), and from eight grasslands in one region (June–July 2014). Each night, a 12 V actinic and black-light trap were placed in the centre of each of three grasslands for 138–317 minutes/night.

(Summarised by: Andrew Bladon)