MANAGEMENT TECHNOLOGIES FOR ARID RANGELANDS
Location: Range Management Research
Title: Badger (Taxidea taxus) disturbances increase soil heterogeneity in a degraded shrub-steppe ecosystem
| Eldridge, D - BOISE STATE UNIV |
| Whitford, W - JORNADA EXPT. RANGE |
Submitted to: Journal of Arid Environments
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 10, 2008
Publication Date: January 1, 2009
Citation: Eldridge, D.J., Whitford, W.G. 2009. Badger (Taxidea taxus) disturbances increase soil heterogeneity in a degraded shrub-steppe ecosystem. Journal of Arid Environments. 73:66-73.
Interpretive Summary: Deserts around the world, including those in western North America, include a number of native animals that modify their environment in significant ways. One common mammal in the western U.S. is the American badger which can be both a significant predator and a disturber of soils through excessive digging and burrowing. This study examined the effects of badger activities in altering soil nutrients within burrowed areas. These disturbed areas have been assumed to be sites for invasion or expansion of undesirable weed species, such as the cheatgrass, across the west. Results from the study indicated that badger activities contribute to altered nutrient ratios in disturbed soils that may actually increase opportunities for native plant species to germinate and survive. These native animals may be important to recovery of landscapes from prior disturbances.
In the western United States, overgrazing, weed invasion and wildfire have resulted in the conversion of shrub-steppe to annual grasslands, with substantial effects on ecosystem function. In these landscapes, badgers disturb large areas of soil while foraging for prey. Mounds created by badgers contained the lowest concentrations of total carbon, nitrogen and sulphur, mineral nitrogen and mineralizable nitrogen, inter-mound soils had the highest concentrations, and excavation pits had intermediate levels. Soil C:N ratio and pH were greater, and electrical conductivity and soluble Ca2, Mg2 and K were lower on mound soils compared with either pit or inter-mound soils. Larger pits generally trapped more litter, and increased litter mass equated with greater concentrations of active carbon, but only at the burned sites. Older mounds supported more vascular plants and cryptogamic crusts. Our results demonstrate reduced levels of nutrients and a higher C:N ratio on the mounds compared with either the pits or inter-mounds. Alteration to the homogeneous post-fire landscape by badgers contributes to patchiness in soils and vegetation, which is critical to the functioning of arid systems. Given their effect on soil C:N ratios, badger-created mounds may be important sites for recovery of indigenous shrub-steppe plant species.