PARENT SESSION
Oral Session 8: Forest Ecology I: Dynamics and Succession.
Presiding: A Fiala and D Kashian
Monday, August 2, 8:00 AM to 11:30 AM, Meeting Room B 117.

Spatial patterns of forest regrowth in old fields: Ghosts of land use past.

Welch, David ^{*,1, 2}, Meretsky, Vicky ^{1, 2}, ¹ Indiana University, Bloomington, IN² Center for the Study of Institutions, Populations, and Environmental Change (CIPEC), Bloomington, IN

ABSTRACT- This study focuses on the impact of seed dispersal limitation and other factors related to distance from seed sources on forest tree diversity in old fields. I quantify differences in the composition and structure of forests based on patterns of establishing seedlings and saplings in old fields. I selected areas of forest with similar land use histories aged 20 to 25 years in southern Indiana. Tree seedlings and saplings were counted and identified on transects (10 m wide) beginning at mature forest edges and penetrating perpendicularly into old fields. Analysis based on the seed dispersal mode and sapling height has revealed spatial relationships with mature forests. Heavy-seeded species are limited in their dispersal based on distance from seed sources. Wind-dispersed species have the highest densities of small seedlings a moderate distance away from the forest edge (15-20m). Seedlings 1m to 3m tall have their highest densities at farther distances from seed sources. The tallest saplings (over 3.5m) have a similar pattern as the shortest wind-dispersed seedlings though the pattern is more subtle. Bird-dispersed species also show a more complicated pattern with distance to seed sources. Some bird-dispersed species show little relationship with distance to seed source while others have higher densities and taller individuals longer distances (50 m+) away from seed sources. This work begins to characterize persistent patterns related to dispersal limitation in forests regrowing from agriculture.

Key words: dispersal , succession, establishment