|ELDRIDGE, D - University Of New South Wales|
|WHITFORD, WALT - New Mexico State University|
Submitted to: Journal of Arid Environments
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/2/2009
Publication Date: 7/1/2009
Citation: Eldridge, D.J., Whitford, W. 2009. Soil disturbance by native animals along grazing gradients in an arid grassland. Journal of Arid Environments. 73:1144-1148.
Interpretive Summary: The study was conducted to identify the type of animal that commonly disturbs the surface of desert soils. Soil surface disturbance in desert environments can lead to excessive amounts of dust and increased amount so water erosion. The study was conducted in a desert area grazed by cattle. However, over 90% of soil disturbances were created by native animals. The main types of disturbances were pits created by rodents, mounds created by spiders, rodents or ants, and termite galleries. Livestock grazing in the study area is properly managed, and the primary cause of soil movement in this area was caused by native animals.
Technical Abstract: Domestic grazing animals that congregate around watering points in arid rangelands create clearly defined trampling-induced grazing gradients. Grazing and trampling alter soil and vegetation condition, often leading to substantial reductions in ecological function. We measured foraging pits and mounds created by native soil foraging animals over 12 months at three watering points in a Chihuahuan Desert grassland, and hypothesized that the density and cover of their disturbances would increase with increasing distance from water. We recorded an average of 3756 disturbances ha_1 and cover of 34.18 m2 ha_1 across the grazing gradients, which comprised mainly pits (43%) and mounds (25%) of heteromyid rodents, ants and spiders. Soil turnover was estimated at 1.43 m3 ha_1. We detected no differences in density, cover, soil volume or composition of disturbances in relation to distance from water, but there were significant, though ill-defined, differences across the five sampling periods, with generally more activity in the warm–wet months. Small animal-created mounds and pits are important sources of soil and sinks for litter within grazing gradients, and may represent the only sites where plants can establish given a relaxation in grazing pressure.