The effects of acid rain and liming on select members of the Ericaceae family

Abstract

Acid rain, characterized by sulphuric acid deposition, poses threats to ecosystems, plants, and animals across Canada. Nova Scotia has a longstanding history of acid rain, influenced by both local sources from industry and air pollution, as well as atmospheric contributions from the northeastern United States. This situation is compounded by the natural acidity of the region's soils, primarily derived from the prevalence of granite bedrock. Greater Sudbury, Ontario is a historical mining town with a long history of acid rain deposition from metal mining that destroyed local flora. Lime, administered as calcium carbonate successfully brought back Lifetree cover to Sudbury, and offers restoration potential elsewhere by neutralizing soil acidity. Despite successful applications in many Canadian forests, Nova Scotia's liming applications are limited. To address this, I applied sulphuric acid and lime to forest plots and monitored chemical, morphological and physiological responses of understory shrubs over a single growing season. A case study was conducted in Sudbury and compared to the experimental results obtained in Nova Scotia. Responses to the treatments were species-specific, with a general reduction of functional traits for the acid treatments. Liming in the short-ter showed indicators of being a positive driver for both teaberries and sheep laurel. Comparative analysis with data from Sudbury, Ontario, plants subjected to long-term liming showed more favorable growth outcomes in limed sites. Here, liming in the long-term increased the leaf pH, calcium (Ca2+) content, and leaf dry matter content (LDMC). The long-term effects of liming were also evident in the lowbush blueberry, as shown in the increase in leaf pH and LDMC. This suggests the potential for positive lime effects on understory shrubs, possibly requiring extended periods for establishment. This study, though preliminary, provides valuable insights into using liming as a restoration strategy in regions impacted by acid rain in Nova Scotia.