Disturbance differentially affects alpha and beta diversity of ants in tallgrass prairies

Abstract

Biodiversity conservation requires understanding how disturbance influences biodiversity patterns at multiple spatial scales. Because the total diversity of species within a given region (c diversity) is influenced by both local diversity (a diversity) and dissimilarity in community composition (b diversity), understanding disturbance effects on both components of diversity is essential, especially if disturbance impacts a and b diversities differently. In this three-year study, we examined how a disturbance (annual harvesting of grasslands) and environmental gradients in the proportion of sand locally, habitat size, and landscape diversity influenced the abundance and a and b diversities of ants within tallgrass prairie habitat in Wisconsin. We used a null-model approach to examine how harvest and environmental factors influence b diversity. Following three years of treatments, we found that ant abundance was greater in harvested sites compared to control sites and ant abundance was positively correlated with soil sandiness. We also found that a diversity was lower in harvested sites compared to control sites and none of the measured environmental gradients influenced a diversity. The effects of harvest on a-diversity patterns may have been mediated through the competitive interactions of the two dominant ant species (Formica montana and Lasius neoniger). In contrast, b diversity (after adjusting for random effects and changes to a diversity) was higher in harvest sites compared to control sites, and variability in community composition was largely driven by the occurrence of rare species. The proportion of sand in the local habitat and habitat size positively influenced b diversity suggesting that community dissimilarity was due in part to environmental filtering and the size of species pools. Because biomass harvest had contrasting effects on ant a and b diversities, trade-offs in maintaining a vs. b diversity might need to be considered in land management and conservation efforts.

Grassland harvesting alters ant community trophic structure: An isotopic study in tallgrass prairies

“…Furthermore, understanding how disturbance affects both the consumer and resource isotopic signatures can offer insight into the mechanisms by which disturbances affect communities and important ecological functions including seed dispersal and predation, aphid tending, top-down control of insect herbivores, and decomposition and nutrient cycling (Agosti, Majer, Alonso, & Schultz, 2000;Blomqvist, Olff, Blaauw, Bongers, & Putten, 2000;Culver & Beattie, 1980;Dostál, 2005). In our previous work in tallgrass prairies, we document changes in both plant and ant diversity following biomass removal (Kim, Bartel, Wills, Landis, & Gratton, 2018;Kim et al, 2017;Spiesman, Bennett, Isaacs, & Gratton, 2017), in part to due to greater openness and changes in the competitive interactions of ants following the disturbance (Andersen, 2019). These changes in habitat structure and resource availability could also affect the feeding behavior of ants within these grasslands (Kaspari, Donoso, Lucas, Zumbusch, & Kay, 2012).…”

“…Data from this study were a part of a larger study examining the effects of biomass harvest on predatory arthropod communities and biocontrol services (Kim et al, 2018(Kim et al, , 2017. Data from this study were a part of a larger study examining the effects of biomass harvest on predatory arthropod communities and biocontrol services (Kim et al, 2018(Kim et al, , 2017.…”

“…This study was conducted in tallgrass prairies in southern Wisconsin in 2013-2016. Data from this study were a part of a larger study examining the effects of biomass harvest on predatory arthropod communities and biocontrol services (Kim et al, 2018(Kim et al, , 2017. These sites were managed by the United States Fish and Wildlife Service (N = 13) and Wisconsin Department of Natural Resources (N = 7) and were at least 2 km away from one another.…”

“…We focus on ants as consumer species because they have diverse diets including plant-derived material such as seeds, nectar, and honeydew from sucking insects, and animal-derived materials including herbivores, predators, and microarthropods such as collembola and springtails. In our previous work in tallgrass prairies, we document changes in both plant and ant diversity following biomass removal (Kim, Bartel, Wills, Landis, & Gratton, 2018;Kim et al, 2017;Spiesman, Bennett, Isaacs, & Gratton, 2017), in part to due to greater openness and changes in the competitive interactions of ants following the disturbance (Andersen, 2019). While there are a few studies that have tested whether disturbance affects trophic structure of ants (e.g., Penick, Savage, & Dunn, 2015;Resasco et al, 2012;Woodcock et al, 2013), these studies did not control for site-level differences in isotopic signatures of baseline resources (i.e., plants) which could also vary with disturbance.…”

Ants of the Palouse Prairie: diversity and species composition in an endangered grassland

“…We found two studies on Tropical & Subtropical Moist Broadleaf Forests ( Lawes et al 2017 , Klunk et al 2018 ), one study on Tropical & Subtropical Coniferous Forests ( Cuautle et al 2016 ), three studies on Temperate Broadleaf & Mixed Forests ( Braschler and Baur 2016 , Helms et al 2020 , Heuss et al 2019 ), one study on Montaine Grasslands & Shrublands ( Jamison et al 2016 ), three studies on Mediterranean Forests, Woodlands & Scrub ( Adams et al 2018 , Catarinue et al 2018 , Flores et al 2018 ) and one study on Deserts & Xeric Shrublands ( Álvarez and Ojeda 2019 ). In the last five years, only two citations have included information on ants in Temperate Grasslands, Savannahs and Grassland biomes ( Ramos et al 2018 , Kim et al 2018 ), the biome that encompasses Palouse Prairie (Fig. 5 ).…”