PARENT SESSION
Poster Session # 14: Forest Ecology.

Wednesday, August 6 Presentation from 5:00 PM to 6:30 PM. SITCC Exhibit Hall B.

Biological diversity associated with bigtooth aspen (Populus grandidentata) clones in a mixed-oak landscape.

Larrimer, Audrey^*,1, McCarthy, Brian¹, ¹ Ohio University, Athens, Ohio

ABSTRACT- Environmental heterogeneity is a commonly proposed mechanism for the maintenance of species diversity. Biotic factors, including forest overstory composition, may contribute to variability in resource availability and environmental conditions, thereby leading to increased understory species richness. The objective of this study was to examine the ability of the clonal species Populus grandidentata to alter resource availability and environmental conditions beneath its canopy, thereby increasing the environmental heterogeneity of the forest landscape as a whole. Twenty P. grandidentata clones were located in southeastern Ohio, and adjacent control sites delineated. Resource availability and environmental factors were quantified in each clone and compared to control sites. Soil pH was found to be significantly greater in P. grandidentata clones than in adjacent control sites (P < 0.05). Percent soil organic matter was significantly less in P. grandidentata clones than in control sites (P < 0.01). No differences in soil nitrate, phosphorus, moisture, or light were detected between treatment and control plots. The results suggest that P. grandidentata alters certain environmental conditions beneath its canopy, possibly through differences in leaf chemistry. A vegetation survey currently underway will evaluate the relevance of microevironmental variation to the composition and structure of understory communities inside and outside of P. grandidentata clones. Observations suggest that P. grandidentata clones may increase forest beta diversity by increasing environmental heterogeneity.

Key words: clonal trees, Populus grandidentata, community ecology, overstory-understory interactions