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Data for: Carbon flow to generalist predators shifts between plant- and fungal-derived resources in highly seasonal ecosystems

Sagi, Nevo1; Manlick, Philip2; Martinez, Anejelique3; Potts White, Leslie4; Newsome, Seth3; Koltz, Amanda1

Research facility: Toolik Field Station
Published Sep 16, 2026 on Dryad. https://doi.org/10.5061/dryad.g1jwstr84

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Sep 16, 2026 version files 58.83 KB

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Abstract

Animals influence biogeochemical processes by consuming other organisms, transferring energy from basal resources up the food chain. Energy is routed through plant, fungal and bacterial channels, and the relative importance of these pathways can shift across space and time. Variation in these pathways may be particularly pronounced in highly seasonal environments where resource availability fluctuates throughout the year. Spatiotemporal variation in the transfer of plant- versus microbial-derived energy to higher trophic levels is poorly understood but can affect bottom-up and top-down processes. For example, seasonal shifts in herbivore versus microbivore availability (bottom-up) may alter prey choice by generalist-feeding predators and lead to changes in top-down predator control on primary production and decomposition. We tested how spatiotemporal variation in primary production influences the use of different energy channels by a widely distributed generalist invertebrate predator in the Arctic tundra. We sampled wolf spiders across four sites spanning a productivity gradient in the Alaskan Arctic during peak summer and on a weekly basis at one focal site throughout the growing season. Using essential amino acid (EAA) carbon isotope (δ¹³C) fingerprinting, we traced the flow of plant-, bacterial- and fungal-derived EAAs to spiders, and quantified the use of plant- versus microbe-based energy channels between sites and across summer. Wolf spiders were associated with more plant- and less fungal-derived carbon assimilation when larger or collected from sites with higher normalized difference vegetation index (NDVI). Across the growing season, spiders shifted from primarily assimilating fungal-based resources in early summer to plant-derived resources in late summer, aligning with seasonal increases in NDVI. These patterns demonstrate spatiotemporal variation in carbon flow through different energy channels and suggest subsequent top-down predator effects may also vary with basal resource availability. Our findings also suggest wolf spider body size may predict whether predation indirectly influences primary production or decomposition. As climate change alters seasonality, resource dynamics, and invertebrate body sizes, these insights provide a basis for predicting spatiotemporal variation in predator impacts on ecosystem processes. Finally, our work demonstrates the utility of compound-specific stable isotope analysis for integrating ecological and biogeochemical theory through the conceptual lens of zoogeochemistry.