Abstract
Small scale distribution of insect root herbivores may promote plant species diversity by creating patches of different herbivore pressure. However, determinants of small scale distribution of insect root herbivores, and impact of land use intensity on their small scale distribution are largely unknown. We sampled insect root herbivores and measured vegetation parameters and soil water content along transects in grasslands of different management intensity in three regions in Germany. We calculated community-weighted mean plant traits to test whether the functional plant community composition determines the small scale distribution of insect root herbivores. To analyze spatial patterns in plant species and trait composition and insect root herbivore abundance we computed Mantel correlograms. Insect root herbivores mainly comprised click beetle (Coleoptera, Elateridae) larvae (43%) in the investigated grasslands. Total insect root herbivore numbers were positively related to community-weighted mean traits indicating high plant growth rates and biomass (specific leaf area, reproductive- and vegetative plant height), and negatively related to plant traits indicating poor tissue quality (leaf C/N ratio). Generalist Elaterid larvae, when analyzed independently, were also positively related to high plant growth rates and furthermore to root dry mass, but were not related to tissue quality. Insect root herbivore numbers were not related to plant cover, plant species richness and soil water content. Plant species composition and to a lesser extent plant trait composition displayed spatial autocorrelation, which was not influenced by land use intensity. Insect root herbivore abundance was not spatially autocorrelated. We conclude that in semi-natural grasslands with a high share of generalist insect root herbivores, insect root herbivores affiliate with large, fast growing plants, presumably because of availability of high quantities of food. Affiliation of insect root herbivores with large, fast growing plants may counteract dominance of those species, thus promoting plant diversity.
Highlights
Insect root herbivores can alter plant community structure by affecting the competitive ability of individual plants [1]
generalized linear mixed effect models (GLMM) analysis revealed that total insect root herbivore numbers in individual soil samples were positively related to community-weighted mean traits indicating high plant growth rates and biomass (Table 3), namely to specific leaf area and reproductive- and vegetative plant height
The presented study aimed at (i) identifying factors that determine the small scale distribution of insect root herbivores in grasslands and (ii) analyzing effects of land use intensity on the Affiliation of insect root herbivores with plants of high biomass, growth rate and tissue quality supports our hypothesis that they are found in spots of high food availability
Summary
Insect root herbivores can alter plant community structure by affecting the competitive ability of individual plants [1]. Patches of different herbivore pressure in a site may add to the heterogeneity of growth conditions for plants and thereby to spatial structuring in vegetation composition at a local scale [3], promoting plant species diversity [4, 5] Despite their potential impact on plant community structure, determinants of the small scale distribution of insect root herbivores are largely unknown [6]. Small scale distribution of insect root herbivores has mostly been investigated for individual pest genera or species in monoculture crop fields It can vary considerably between fields, and has been found to correlate with spatial variation of soil characteristics, soil moisture or host plant abundance [9, 12, 13]. Studying the determinants of insect root herbivores in diverse plant communities may contribute to our understanding of stabilizing mechanisms for plant species diversity (sensu [16])
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
