PARENT SESSION
Poster Session # 13: Biogeochemistry, Photosynthesis, and Respiration.
Tuesday, August 5 Presentation from 5:00 PM to 6:30 PM. SITCC Exhibit Hall B.
Carbon and macronutrient content of herb layer vegetation in an Indiana temperate deciduous forest.
Welch, Nicole*,1, Belmont, Jonathon2, Randolph, J.C.2, 1 Middle Tennessee State University, Murfreesboro, TN2 Indiana University, Bloomington, IN
ABSTRACT- While herb layer tissue nutrient content (mg/g) often decreases with CO2 enrichment, the increase in plant biomass under these conditions results in an overall increase in nutrient content of the herb layer (g nutrient/m2). Baseline herb layer nutrient and biomass data will be crucial for detecting if similar changes occur in the field with global climate change. This study assessed biomass and carbon and macronutrient concentrations of herb layer vegetation (forest vegetation <1 m in height) at the AmeriFlux Tower Site in the Morgan-Monroe State Forest, Indiana. Two hundred and fifteen 1-m2 plots were sampled for herb layer species composition and cover. Forty of these plots were harvested for above ground biomass determination and tissue nutrient analysis. Lindera benzoin, Boehmeria cylindrica, Viola sp., Parthenocissus quinquefolia, and Ploystichum acrostichoides were the most important herb layer species. Mean herb layer biomass was 38.50+8.08 g/m2. Forbs accounted for approximately 14.56 g/m2 of the herb layer vegetation followed by grasses (5.73 g/m2) and woody shrubs and seedlings (21.06 g/m2). Forbs, grasses, and woody shrubs and seedlings averaged 6.04, 2.32, and 9.54 g C/m2, respectively. In general, macronutrient concentrations for these herb layer components were N > K > Ca > Mg > P. Mean macronutrient concentrations were highest in forbs (0.35 g N/m2, 0.45 g K/m2, 0.15 g Ca/m2, 0.06 g Mg/m2, 0.26 g P/m2) followed decreasingly by woody shrubs and seedlings, and grasses. Predicted increases in CO2 with global climate change could alter these nutrient concentrations and, in turn, alter forest nutrient cycles and herbivore food quality.
Key words: nutrient cycles, herb layer, global climate change