Tracing herbivore effects on litter decomposition in the Yukon-Kuskokwim River Delta 06/17/2022 - 06/16/2023

Herbivores alter abiotic characteristics in their habitats as well as litter quality, both characteristics which are known to change litter decomposition rates. In the Yukon-Kuskokwim (Y-K) River Delta, geese act as ecosystem engineers, altering vegetation and carbon cycling, but it is unknown how or if they affect litter decomposition rates. To determine potential impacts of herbivores on litter decomposition, we performed a field litter bag study in which we collected two different qualities of litter representing grazed and ungrazed conditions, and incubated them in grazed ‘grazing lawn’ and ungrazed ‘Carex meadow’ habitats in the Yukon Delta National Wildlife Refuge, a subarctic wetland ecosystem (Coordinates: 61.313439, -165.54306). We collected bags at 3, 6, 9, and 52 weeks (from 6/17/2022 - 6/16/2022), and measured the biomass loss. Abiotic conditions were monitored in each habitat to quantify potential environmental conditions affecting litter decomposition dynamics. We also measured carbon, nitrogen, and lignin concentrations at each timepoint to determine degradation of labile and recalcitrant materials.