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We conducted a manipulative experiment to quantify the impact of small mammal herbivores on the belowground biogeochemistry of the tundra at three sites near Toolik Lake, Alaska. At each site we set up grazing fences in July of 2018 to simulate different levels of small mammal herbivore (vole and lemming) activity. Each site had 3 treatment plots and a control plot: 1)Exclosure treatments (EX) were 8 meter (m) x 8m square mesh fences 2) control plots (CT) were 8m x 8m unfenced plots marked with pin flags at corners 3) press treatments (PR) were 20m x 20m square mesh fences stocked with 4 tundra voles (Microtus oeconomus) every summer except for 2024 and 4) pulse treatments (PU) where we stocked the fence with 4 voles in 2018 and then removed and excluded voles from 2019 onward. At each site we collected temperature measurements using iButton data loggers from the soil surface, the soil organic layer, and the soil mineral layer every 4 hours from 2018 - 2024. iButton loggers were removed and replaced after soil thaw every summer. 

We conducted a manipulative experiment to quantify the impact of small mammal herbivores on the belowground biogeochemistry of the tundra at three sites near Toolik Lake, Alaska. At each site we set up grazing fences in July of 2018 to simulate different levels of small mammal herbivore (vole and lemming) activity. Each site had 3 treatment plots and a control plot: 1)Exclosure treatments (EX) were 8 meter (m) x 8m square mesh fences 2) control plots (CT) were 8m x 8m unfenced plots marked with pin flags at corners 3) press treatments (PR) were 20m x 20m square mesh fences stocked with 4 tundra voles (Microtus oeconomus) every summer and 4) pulse treatments (PU) where we stocked the fence with 4 voles in 2018 and then removed and excluded voles from 2019-2022. At each site we collected 10 thaw depth measurements along a transect from each treatment. 

Soil and plant sampling analysis under small mammal-built structures and controls sites from near the Team Vole fences: Nome, Toolik, Utqiagvik, AK 2018-2020. 

Percent cover of tundra vole and brown lemming structures collected from within the Team Vole enclosure/exclosure fences near Nome, Toolik, Utqiagvik, AK 2019. 

This data describes above-ground and below-ground variables collected under small mammal-built structures and control sites from two tundra locations in polygonal tundra near Utqiagvik, Alaska, USA. Small mammal structures sampled included hay piles (winter nests), runways, latrines, and burrow entrances. Above-ground data collected include relative percent cover, litter depth, and Normalized Difference Vegetation Index. Below-ground data collected include inorganic soil nutrients, total extractable soil nutrients, microbial biomass nutrients, microbial exo-enzyme activities, soil pH, soil conductivity, soil temperature, and soil respiration. 

Abstract Understanding arctic ecosystem function is key to understanding future global carbon (C) and nutrient cycling processes. However, small mammal herbivores can have effects on ecosystems as structure builders and these effects have been underrepresented in the understanding of arctic systems.We examined the impact of small mammal structures (hay piles, runways, latrines) on soils and plants in three arctic tundra regions near Utqiaġvik, Toolik Lake, and Nome, Alaska. Our aims were to (1) examine how vole and lemming structures influence plant and soil nutrient pools and microbial processes, (2) determine if structure effects were similar across tundra system types, and (3) understand how changes in the abundance and cover of these structures during different phases of small mammal multi‐annual population cycles might influence biogeochemical cycling.In general, small mammal structures increased nitrogen (N) availability in soils, although effects varied by study region. Across study regions, hay piles were relatively uncommon (lowest % cover) but increased multiple soil N and P pools, C‐ and N‐acquiring enzyme activities, and leaf phosphorus (P) concentrations, with the specific nutrient variables and size of the effects varying by study region. Latrines had the second highest cover and influenced multiple C, N and P pools, but their effects were mainly observed within a single region. Lastly, runways had the highest % cover of all activity types but increased the fewest number of soil nutrient variables.We conclude that by influencing soil nutrient availability and biogeochemical cycling, small mammal structures can influence bottom‐up regulation of ecosystem function, particularly during the high phase of the small mammal population cycle. Future changes in these population cycles might alter the role of small mammals in the Arctic and have lasting effects on system processes. Read the freePlain Language Summaryfor this article on the Journal blog