You are here:
Assessing ecological risks from atmospheric deposition of nitrogen and sulfur to US Forests using epiphytic macrolichens
Citation:
Geiser, L., P. Nelson, S. Jovan, H. Root, AND C. Clark. Assessing ecological risks from atmospheric deposition of nitrogen and sulfur to US Forests using epiphytic macrolichens. Diversity. MDPI, Basel, Switzerland, 11(6):87, (2019). https://doi.org/10.3390/d11060087
Impact/Purpose:
The purpose of this paper is to establish updated critical loads for the effects from nitrogen and sulfur deposition on lichens across the U.S. It was led by USFS researchers and will be considered by OAQPS in their review of the secondary standards of NOx and SOx.
Description:
Critical loads of atmospheric deposition help decision-makers identify harmful levels of air pollution. But when critical loads are exceeded, how can the accompanying environmental risk be quantified? We use epiphytic macrolichens to assess risks from nitrogen and sulfur-containing air pollutants. Specifically, we use 90% quantile regression to model relationships between deposition and manager concerns: species richness, abundance of functional groups with integral ecological roles, and rare species occurrences. We tabulate 20, 50, and 80% declines in these biological responses to represent low, moderate, and high ecological risk cut-offs. Data utilized national-scale lichen surveys, sensitivity ratings, and modeled deposition and climate data for US forests. Critical loads (low risk) for total species richness, sensitive species richness, forage lichen abundance and cyanolichen abundance, respectively, were 3.5, 3.1, 2.0, and 1.3 kg N and 6.0, 2.5, 2.6, and 2.3 kg S ha-1 yr-1. The high environmental risk cut-offs (80% decline), excluding total species richness, were 14.8, 10, and 6.6 kg N and 14.1, 13, and 11 kg S ha-1 yr-1. These risks were further characterized in relation to effect timeframes, climate, number of species impacted, uncertainties, and effects on interdependent biota, nutrient cycling, and ecosystem services.
URLs/Downloads:
DOI: Assessing ecological risks from atmospheric deposition of nitrogen and sulfur to US Forests using epiphytic macrolichens