PARENT SESSION
Poster Session #16: Fire Ecology.
Tuesday, August 7, 2001. Presentation from 3:30 PM to 5:00 PM. Exhibition Hall

Within-site genetic variation is negatively correlated with average stem diameter in post-fire Yellowstone aspen seedlings .

Stevens, Michael¹, Turner, Monica¹, Tuskan, Gerald², Romme, William³, Gunter, Lee², Waller, Donald¹, ^{1 2 3}

ABSTRACT- Aspen (Populus tremuloides Michx.), which primarily reproduces clonally via root sprouts in western North America, regenerated by seeds after extensive fires in Yellowstone National Park (YNP), Wyoming, USA, in 1988. To determine how genetic diversity relates to site environmental characteristics and plant size, we sampled 410 aspen seedlings from 23 local populations distributed widely across YNP in 1997. We used randomly amplified polymorphic DNA (RAPD) markers from six primers to characterize genetic variation within sites. Mean within-site genetic distance was negatively correlated with average aspen stem diameter (P = 0.02, R² = 0.21). In 1998 and 2000, we resampled the aspen study sites and found that genetic variation and stem diameter remained negatively correlated (1998: P = 0.005, R² = 0.34; 2000: P = 0.004, R² = 0.34). These results provide additional evidence that as post-fire aspen seedlings grow, genetic diversity within sites may decline, approaching that of monoclonal mature stands.

KEY WORDS: genetic variation, Populus tremuloides, RAPD, regeneration