Development of microtopography in a semi-arid grassland: effects of disturbance size and soil texture

• Published in: Plant and soil Vol. 191; no. 2; pp. 163 - 171
• Main Authors: Martinez-Turanzas, G.A. (Colorado State Univ., Fort Collins, CO (USA). Rangeland Ecosystem Science Dept.), Coffin, D.P, Burke, I.C
• Format: Journal Article
• Language: English
• Published: Dordrecht Kluwer Academic Publishers 01-04-1997; Springer; Springer Nature B.V
• Subjects: Aerial parts; Agricultural soils; Agronomy. Soil science and plant productions; ARID SOILS; Biological and medical sciences; BOUTELOUA; Bouteloua gracilis; Clay loam; Coffins; COMMUNAUTE VEGETALE; COMUNIDADES VEGETALES; COUVERTURE VEGETALE; CUBIERTA VEGETAL; Disturbance; Dominant species; ECOLOGICAL SUCCESSION; Fundamental and applied biological sciences. Psychology; GRASSLAND SOILS; Grasslands; PLANT COMMUNITIES; PLANT COVER; PLANT SOIL RELATIONS; Plants; RELACIONES PLANTA SUELO; RELATION PLANTE SOL; Sandy loam; Semiarid grasslands; Soil disturbance; Soil erosion; Soil erosion, conservation, land management and development; Soil science; Soil texture; Soils; SOL D'HERBAGES; SOL DE ZONE ARIDE; Steppe soils; Steppes; SUCCESSION ECOLOGIQUE; SUCESION ECOLOGICA; SUELO ARIDO; SUELO DE PRADERAS; United States; North America; Colorado; America; USA, Colorado; Grassland; Monocotyledones; Soil erosion; Small scale; Perennial plant; Property of soil; Bouteloua gracilis; Perturbation; Texture; Clay loam soil; Microrelief; Gramineae; Semi arid zone; Topography; Angiospermae; Spermatophyta; Plant cover; Fodder crop; Population density; Sandy loam soil
• ISSN: 0032-079X; 1573-5036
• DOI: 10.1023/A:1004286605052

Our objective was to evaluate effects of disturbance size and soil texture on the development of microtopography for a shortgrass plant community in north central Colorado USA. Disturbances, defined as the death of individual plants, were created in 1984 and 1985 to evaluate development through time of the small-scale pattern of perennial bunchgrasses and bare soil openings that characterize this semiarid grassland. Disturbed plots of three sizes (50, 100, 150 cm-diameter) comparable in size to naturally-occurring disturbances were produced by killing plants at two sites differing in soil texture (sandy loam, clay loam). Disturbed plots were not manipulated after being created. In 1993, a laser surveying instrument was used to measure heights of crowns of individual plants of the dominant species, the perennial bunchgrass Bouteloua gracilis ([H.B.K.] Lag. ex Griffiths), and bare soil openings between plants for two locations: within each disturbance and in the surrounding undisturbed landscape. Differences between crown heights of plants and bare soil openings were comparable for both the undisturbed landscape and inside disturbances indicating that small-scale microtopography had recovered within nine years after disturbance occurred. However, complete recovery to the undisturbed state had not occurred since crown heights of plants relative to bare soil openings were significantly less on disturbed than undisturbed locations. Differences in height between plant crowns and bare soil openings on disturbed plots increased as disturbance size increased, indicating greater soil redistribution with increasing plot size. Larger differences in height were also found on plots on the fine-than the coarse-textured soil, indicating the importance of soil particle size and plant cover type to the development of microtopography. Differences in height between microsites on disturbed plots were positively related to total plant cover and negatively related to cover of B. gracilis indicating the importance of this species to reducing erosion on disturbed areas. In this semiarid grassland, patterns in microtopography were heterogeneous, likely as a result of the small-scale redistribution of soil between bare soil openings and B. gracilis plants through time. Our results indicate that this redistribution of soil is affected by disturbance size, soil texture, and patchy plant cover. The major effect of small-scale disturbances on patterns in microtopography of the shortgrass steppe are causing plant death and exposing soil to erosional and depositional processes.