Planted grasslands have equivalent or higher arthropod biomass than native grassland important to nesting Sprague's Pipits ( Anthus spragueii ) early in the breeding season
David Anthony Kirk, Juan Andrés Martínez‐Lanfranco, Kimberly M. Dohms, R. Mark Brigham, Stephen K. DavisAbstract
Introduction
Grassland species are declining globally. Sprague's Pipit ( Anthus spragueii ), a native grassland‐obligate, nests in planted grasslands in some regions. How food resources in planted grassland compare with those in native grassland is important to determine the relative benefits of creating new grassland by seeding cropland with non‐native vegetation.
Objective
We assessed whether arthropod biomass and diversity within plots where pipits nested and paired random plots differed between native and planted grassland, controlling for date, year, and sampling method and according to early season temporal variability.
Methods
Using pitfall traps and sweep nets, we sampled arthropods near 14 nests (7 native, 7 planted) paired with random plots within two native and three planted grasslands.
Results
No difference was found in biomass between nest versus random plots, so we combined data for analysis. For pitfall traps, effects were significant for grassland type; in both years, Acari biomass was higher in native grassland; Diptera, Hymenoptera, and Orthoptera had higher biomass in planted grassland. For sweep nets, there was no effect of grassland type, but the effects of year, date, and grassland type × year were significant. In 2007, higher biomass was found in planted grassland. In both years, Acari and Orthoptera had higher biomass in native grassland; Hemiptera had higher biomass in planted grassland. Grassland type had a significant effect on arthropod diversity for both trapping techniques.
Conclusions
Our results indicate that planted grassland in our region has similar or higher biomass of potential prey for pipits versus native grassland early in the nesting season.