Productivity and diversity of annually harvested reconstructed prairie communities

Climate vs Energy Security: Quantifying the Trade-offs of BECCS Deployment and Overcoming Opportunity Costs on Set-Aside Land

Bioenergy with carbon capture and storage (BECCS) sits at the nexus of the climate and energy security. We evaluated trade-offs between scenarios that support climate stabilization (negative emissions and net climate benefit) or energy security (ethanol production). Our spatially explicit model indicates that the foregone climate benefit from abandoned cropland (opportunity cost) increased carbon emissions per unit of energy produced by 14-36%, making geologic carbon capture and storage necessary to achieve negative emissions from any given energy crop. The toll of opportunity costs on the climate benefit of BECCS from set-aside land was offset through the spatial allocation of crops based on their individual biophysical constraints. Dedicated energy crops consistently outperformed mixed grasslands. We estimate that BECCS allocation to land enrolled in the Conservation Reserve Program (CRP) could capture up to 9 Tg C year-1 from the atmosphere, deliver up to 16 Tg CE year-1 in emissions savings, and meet up to 10% of the US energy statutory targets, but contributions varied substantially as the priority shifted from climate stabilization to energy provision. Our results indicate a significant potential to integrate energy security targets into sustainable pathways to climate stabilization but underpin the trade-offs of divergent policy-driven agendas.

Functional roles of ants in a temperate grassland

Ants in temperate grasslands are consumers and ecosystem engineers, influencing biodiversity and potentially grassland productivity. However, the effects of ant exclusion or suppression on resource removal and the biological community in temperate grasslands have yet to be fully explored. We conducted ant-suppression experiments and evaluated the effects of ants on ground-dwelling arthropod communities in the field by using pitfall and bait traps. In the laboratory, we evaluated the effects of ants on the ant-attended aphid Aphis rumicis, which is a honeydew resource for ants, and the slug (Deroceras laeve), an aphid predator. Aboveground arthropod communities were not affected by the ant-suppression treatment. However, slugs (D. laeve and Ambigolimax valentianus) visited bait resources more frequently in the ant-suppression treatment area. In the ant-absence condition in the laboratory experiment, there were fewer aphids on the plants compared to the ant-presence condition owing to predation by D. laeve. Our results suggest that ant abundance in temperate grasslands influences the predation activity of slugs toward honeydew sources such as aphids.

Helianthus maximiliani and species fine-scale spatial pattern affect diversity interactions in reconstructed tallgrass prairies

Biodiversity and Ecosystem Function analyses aim to explain how individual species and their interactions affect ecosystem function. With this study, we asked in what ways do species interact, are these interactions affected by species planting pattern, and are initial (planted) proportions or previous year (realized) proportions a better reference point for characterizing grassland diversity effects?We addressed these questions with experimental communities compiled from a pool of 16 tallgrass prairie species. We planted all species in monocultures and mixtures that varied in their species richness, evenness, and spatial pattern. We recorded species-specific biomass production over three growing seasons and fitted Diversity-Interactions (DI) models to annual plot biomass yields.In the establishment season, all species interacted equally to form the diversity effect. In years 2 and 3, each species contributed a unique additive coefficient to its interaction with every other species to form the diversity effect. These interactions were affected by Helianthus maximiliani and the species planting pattern. Models based on species planted proportions better-fit annual plot yield than models based on species previous contributions to plot biomass.Outcomes suggest that efforts to plant tallgrass prairies to maximize diversity effects should focus on the specific species present and in what arrangement they are planted. Furthermore, for particularly diverse grasslands, the effort of collecting annual species biomass data may not be necessary when quantifying diversity effects with DI models.