Effects of the northern pocket gopher (Thomomys talpoides) on alpine soil characteristics, Niwot Ridge, CO

Effects of the northern pocket gopher (Thomomys talpoides) on surface soilcharacteristics were examined at the alpinesite of Niwot Ridge, CO. We measured erosionof soil from gopher mounds and compared thecharacteristics of gopher mound (disturbed) andundisturbed soils in two major plant communitytypes. Our measurements of erosion indicatelong-term susceptibility of gopher-disturbedsoils to redistribution by water and/or wind inthis ecosystem. Ecosystem heterogeneityintroduced by the gopher is reflected insignificantly lower SOM in gopher mounds thanin surrounding undisturbed soils, acharacteristic which appears to be causallyassociated with other effects of gopherdisturbance including changes in soil textureand significantly lower clays, total C, totalN, total P, and labile P. In contrast toplant-available P, NO₃^– was higherand steadily increased for the short term in both gopher mound soils and those beneath the mounds. These pools of NO₃^– thendecreased to pre-disturbance levels by thefollowing spring. Collectively our resultsindicate that, through the physicalmanipulation of soil and subsequent effects onsoil resources, the northern pocket gopherfunctions as an agent of increased ecosystemheterogeneity and soil mass and nutrientredistribution at Niwot Ridge.