Agriculture land-use change seasonally rewires stream food webs: A case study from headwater streams in the Lake Erie watershed

Human impacts, like agricultural land-use change, alter natural patterns of resource availability and consumer response through space and time threatening the stability of ecosystems. In streams, removal of riparian zones and nutrient loading through agriculture may alter seasonal asynchronous resource fluxes and lead to food web rewiring and stability loss. Here, we seasonally sampled three streams across an agricultural gradient to determine how agricultural land-use change rewires seasonal stream food web structures. We show that agricultural land-use change seasonally rewired trophic interactions through reduced terrestrial energy use and trophic position. Additionally, agricultural land-use change drove steeper biomass size spectrum slopes and shifted fish communities to high abundances of small individuals. Collectively, our results suggest agricultural land-use change may be homogenizing stream food webs towards productive, single-energy channel dominated webs with faster turnove..., , , # Agriculture land-use change seasonally rewires stream food webs: A case study from headwater streams in the Lake Erie watershed

[https://doi.org/10.5061/dryad.sj3tx96fp](https://doi.org/10.5061/dryad.sj3tx96fp)

## Description of the data and file structure

The study was conducted in three headwater streams (stream order </= 3) along the north shore of Lake Erie, Ontario, a region with high cover of agricultural land. We collected seasonal stable isotope, stomach contents, fish community composition and supporting stream characteristic data from three streams spanning a gradient from low to high agricultural impact. For each stream, wetted width (cm), water depth (cm), and hydraulic head (estimate of relative flow velocity, cm) were measured twice a week from the beginning of May to the beginning of November 2018 (May 3, 2018 – November 5, 2018). Total nitrogen (N), total phosphorous (P) and % algal cover was measured at each of the streams monthly from June – August 2018.  Sampling...