- Beier, Colin
SUNY College of Environmental Science and Forestry, Adirondack Ecological Center
Acid rain has been a chronic and pervasive problem across much of the Northern Forest for decades. Acid rain causes the leaching and loss of calcium (Ca), a critical nutrient for all organisms, from forest soils. However, the impact of Ca depletion on forest organisms and ecological communities is not well understood in the Northern Forest region. In some forests, the presence of Ca-rich bedrock provides a buffering capacity that resists acidification and helps to maintain the availability of Ca in the food web.
We studied the potential importance of these Ca-rich forest patches by sampling snail, salamander, arthropod and plant communities in the Adirondack Mountains of northern New York. We selected twelve sites representing the full range of soil Ca in the Adirondacks to determine whether differences in biodiversity and productivity were related to the availability of Ca. We also sampled the diets of woodland salamanders to understand how Ca influences the forest floor food web.
We found that snail and salamander communities were strongly influenced by soil Ca, while the effect of Ca on plant and insect communities was less clear. Snail abundance and diversity was positively related to soil Ca. Red-back salamanders – a keystone species in northern hardwood forests – increased in abundance with increasing soil Ca. Several snail and plant species were found only at the 2-3 highest Ca sites, indicating that these forests may act as refuges for highly Ca-dependent organisms.
Overall, this study provided evidence of the importance of Ca for many different forest species and communities, which will support future research, conservation and regulatory efforts to mitigate acid rain impacts in the Northern Forest region.