Time-Of-Flight monitoring reveals higher sediment redistribution rates related to burrowing animals than previously assumed

Abstract

Abstract. Burrowing animals influence surface microtopography and hillslope sediment redistribution, but changes often remain undetected due to a lack of autonomous high resolution field monitoring techniques. In this study we present a new approach to quantify microtopographic variations and surface changes caused by burrowing animals and rainfall-driven erosional processes applied to remote field plots in arid and mediterranean Chile. We compared the mass balance of redistributed sediment within plot areas affected and not affected by burrowing animals, quantified the cumulative sediment redistribution caused by animals and rainfall, and upscaled the results to the hillslope scale. The new instrument showed a very good detection accuracy. The cumulative sediment redistribution within areas affected by burrowing animals was higher (−10.44 cm3 cm−2 year−1) in the mediterranean than the arid climate zone ( −1.41 cm3 cm−2 year−1). Daily sediment redistribution during rainfall within areas affected by burrowing animals were up to 350 % / 40 % higher in the mediterranean / arid zone compared to the unaffected areas, and much higher than previously reported in studies not based on continuous microtopographic monitoring. Furthermore, 38 % of the sediment eroding from the burrows accumulated within the burrow entrance while 62 % was incorporated into overall hillslope sediment flux. The cumulative sediment excavation by the animals was 14.62 cm3 cm−2 year−1 in the mediterranean and 16.41 cm3 cm−2 year−1 in the arid climate zone. Our findings can be implemented into long-term soil erosion models that rely on soil processes but do not yet include animal-induced surface processes on microtopographical scales in their algorithms.

Vegetation and vertebrate abundance as drivers of bioturbation patterns along a climate gradient

“…In a further study, we will therefore compare physical and chemical soil properties in areas with soil affected and unaffected by bioturbation along the same climatic gradient. Additionally, our findings support the importance of examining impacts of bioturbation on ecosystem processes on a broader climatic scale and thereby encourage similar further studies like the assessment of sediment redistribution rates caused by bioturbation [71].…”