Burrowing Through the Literature: The Impact of Soil-Disturbing Vertebrates on Physical and Chemical Properties of Soil.

Soil-disturbing vertebrates (SDV) are relatively low in biodiversity and biomass compared with the dominant soil fauna (microorganisms and invertebrates), but they can nevertheless have a great impact on the physical and chemical properties of soils. Our goal is to take an ichnological (organism-substrate interactions)-based approach to review the impacts of SDV on soils; these impacts result in three basic categories of physical structures (traces): subterranean excavations, constructed surficial mounds, and surficial excavations and depressions. We focus on direct rather than indirect effects and frame these in terms of soil additions, losses, translocations, and transformations. We look at publication trends in the SDV literature and graphically summarize examples of maximum reported construction heights, excavation depths, and volumes of soil displacement for various SDV . We then review SDV impacts on soil color, texture, horizonation, structure, bulk density, soil moisture, porosity and permeability, organic matter, pH, cation exchange capacity, and the nutrients Ca, Mg, N, K, P, S, and Si. Translocations are common sources of variation in these properties and may be especially important in creating nutrient-rich patches in otherwise limited landscapes. Common results of SDV activity include destruction of soil structure, decreases in bulk density, and increases in infiltration rates, porosity, and permeability. Additions of excrement and plant material are important sources of organic matter, N, and K. Direct soil losses may occur through geophagy and trampling and wallowing behaviors. Erosion is an important indirect impact often related to killing of surface vegetation from mounding and foraging behaviors. [ABSTRACT FROM AUTHOR]