Main content area

Differential seedling performance and environmental correlates in shrub canopy vs interspace microsites

Boyd, C. S., Davies, K. W.
Journal of arid environments 2012 v.87 pp. 50
Agropyron cristatum, Artemisia tridentata subsp. wyomingensis, Pseudoroegneria spicata, canopy, environmental factors, fire ecology, leaf area, microhabitats, plant communities, plant density, seedlings, seeds, semiarid zones, shrubs, soil color, soil temperature, wind erosion, Oregon
Shrubs in semi-arid ecosystems promote micro-environmental variation in a variety of soil properties. We compared post-fire seeding success and soil variables between shrub (“under-canopy”) and interspace locations for hand-seeded bluebunch wheatgrass (Pseudoroegneria spicata) and crested wheatgrass (Agropyron cristatum) in Wyoming big sagebrush (Artemisia tridentata) plant communities in southeast Oregon, U.S.A. We burned 5, 20 x 20 m sites in October, 2009 and established paired under-canopy and interspace micro-transects. Transects were seeded to bluebunch wheatgrass (193 seeds/m) or crested wheatgrass (177 seeds/m). We monitored seedling density in 2010, and measured soil-related environmental variables. Seedling density was 69% higher for crested wheatgrass and 75% higher for interspace locations. Decreased density in under-canopy was associated with wind erosion of seeds. Tiller and leaf area production were over twice as high (p < 0.05) in under-canopy locations. Six of 24 soil variables differed (p < 0.10) between locations. These six variables, particularly soil color and soil temperature, explained 19 - 32% of variation in seedling performance. Shrub effects on seeding success are complex and interact with abiotic disturbances, but patterns of increased seedling performance in under-canopy locations and their relationships to soil variables may suggest tactics for increasing success of restoration practices.