PARENT SESSION
Poster Session # 14: Forest Ecology.
Wednesday, August 6 Presentation from 5:00 PM to 6:30 PM. SITCC Exhibit Hall B.
Climate variability and tree species recruitment, implications on species coexistence.
Ibáñez, Inés*,1, Clark, James1, LaDeau, Shannon1, 1 Duke University, Durham, North Carolina
ABSTRACT- Climate variability will affect natural plant communities, in part, through its impact on recruitment dynamics. In this study, we estimated the differential influence of climatic patterns on seedling establishment of several dominant tree species. Using ten years of data on climate, seed rain, and seedling censuses, we develop a hierarchical Bayes model to quantify establishment of dominant species at five stands of secondary temperate forest in the Southern Appalachians. Establishment (logistic regression) was estimated as a function of environmental variables (temperature and soil moisture) and adjusted for seed rain. Coefficients linked with each climatic variable are reported here. Years having the lowest minimum temperature during the germination season resulted in poor establishment of the two Betula species (coefficient mean±SD: -0.188±0.08), both of which occur primarily in the upper elevation stands. On the other hand, low spring temperatures enhanced recruitment of Acer rubrum (0.47±0.02) and Nyssa sylvatica (0.58±0.14), species that grow in warm, low-elevation stands. Quercus rubra establishment was also most successful in years with low temperatures (0.32±0.14). In addition to temperature, precipitation (measured as soil moisture content during the germination season) affected seedling establishment. Betula spp. (0.09±0.008), Liriodendron tulipifera (0.25±0.08), and Q. rubra (0.13±0.03) experienced enhanced establishment during years with relatively high precipitation. N. sylvatica, a species that occurs primarily on dry sites in our region, established more successfully during dry years (-0.18±0.03). Results from this study confirm the influence of climate variability on seedling establishment, and its distinct effect on particular species.
Key words: climate variability, species coexistence, seedling establishment, Bayes model