Introduction to: Air Pollution Effects on Forests: A Guide to Species Ecology, Ecosystem Services, and Responses to Nitrogen and Sulfur Deposition. Herbs (Volume 2)

This report assesses the risks from N and S deposition on 198 herbaceous plant species of the continental United States. Information for each species has been compiled from several peer-reviewed Federal and non-Federal sources. Seventy-one species are featured in detail. For each featured species, we provide information on seven topics: the (1) distribution and conservation status, (2) species characteristics and habitat, (3) wildlife and livestock uses, (4) other ecosystem services, (5) traditional ecological knowledge, (6) responses to N and S deposition, climate, soil pH, including interactions, (7) critical loads (CLs; deposition rates below which harm does not occur), confidence in the CLs, and geographic areas where CLs exceeded modeled deposition estimates for 2019–2021. The remaining 127 species did not have easily accessible ecological and ecosystem services information. For each of these species, we provide maps for topics (1) and (7) in the appendix. This report is part of a three-volume series covering the N and S deposition responses of trees (vol. 1), herbs (this vol. 2), and lichens (vol. 3).

Impact/Purpose

This is the introduction to a USFS General Technical Report (GTR), on the vulnerability of species to N and S deposition. All the material is from already published material (vol. 1, trees = Horn et al. 2018; vol. 2 (this one), herbs = Clark et al. 2019; vol. 3, lichen = Geiser et al. 2020/21).  This research determines which areas and species are most at risk from atmospheric deposition of N and S, and is relevant for air quality managers and land managers (e.g., at EPA, US Forest Service, National Park Service, and States).

Citation

Clark, Christopher M., M. Bell, F. Gilliam, K. Dillman, L. Geiser, L. Pardo, A. Eagleton, AND H. Mesraty. Introduction to: Air Pollution Effects on Forests: A Guide to Species Ecology, Ecosystem Services, and Responses to Nitrogen and Sulfur Deposition. Herbs (Volume 2). U.S. Environmental Protection Agency, Washington, D.C., 2026. [DOI: 10.2737/FS-1256]

• https://research.fs.usda.gov/treesearch/80439

DOI: Introduction to: Air Pollution Effects on Forests: A Guide to Species Ecology, Ecosystem Services, and Responses to Nitrogen and Sulfur Deposition. Herbs (Volume 2)