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Full-Text Articles in Forest Sciences
Terrestrial Gastropod Responses To An Ecosystem-Level Calcium Manipulation In A Northern Hardwood Forest, Monica A. Skeldon, Matthew A. Vadeboncoeur, Steven P. Hamburg, Joel D. Blum
Terrestrial Gastropod Responses To An Ecosystem-Level Calcium Manipulation In A Northern Hardwood Forest, Monica A. Skeldon, Matthew A. Vadeboncoeur, Steven P. Hamburg, Joel D. Blum
Earth Systems Research Center
The effects of acid deposition on soil calcium (Ca), and in turn on land snail populations, have been of heightened concern for several decades. We compiled a 10 year record (1997–2006) of gastropod abundance on two small watersheds at the Hubbard Brook Experimental Forest, one of which was treated with a Ca addition in 1999. In years 3–7 post Ca addition, snail abundance in the treated watershed was 73% higher than in the reference area (p < 0.001); there was no significant difference in the 3 years prior to treatment, and no significant difference in slug abundance in any year. We analyzed relationships between snail density and microsite spatial variation in leaf-litter Ca concentration, litter-layer thickness, tree species composition, slope, dead wood, and forest-floor light level. We found that snail abundance was significantly correlated with litter Ca concentration (p < 0.001) and negatively correlated with the importance value of American beech (p = 0.05). Isotopic-tracer analysis indicated that, on average, 76% of Ca in snail shells 5 years post treatment was derived from the added Ca. However, interannual variation in snail numbers indicates that other factors beyond available Ca have a strong influence on snail abundance.
Validation And Refinement Of Allometric Equations For Roots Of Northern Hardwoods, Matthew A. Vadeboncoeur, Steven P. Hamburg, Ruth D. Yanai
Validation And Refinement Of Allometric Equations For Roots Of Northern Hardwoods, Matthew A. Vadeboncoeur, Steven P. Hamburg, Ruth D. Yanai
Earth Systems Research Center
The allometric equations developed by Whittaker et al. (1974. Ecol. Monogr. 44: 233–252), at the Hubbard Brook Experimental Forest have been used to estimate biomass and productivity in northern hardwood forest systems for over three decades. Few other species-specific allometric estimates of belowground biomass are available because of the difficulty in collecting the data, and such equations are rarely validated. Using previously unpublished data from Whittaker’s sampling effort, we extended the equations to predict the root crown and lateral root components for the three dominant species of the northern hardwood forest: American beech (Fagus grandifolia Ehrh.), yellow birch (Betula alleghaniensis …