Linda H. Geiser

TL;DR: Nitrogen deposition in the western United States ranges from 1 to 4 kilograms (kg) per hectare (ha) per year over much of the region to as high as 30 to 90 kg per ha per year downwind of major urban and agricultural areas.

TL;DR: In this article, the authors synthesize current research relating atmospheric N deposition to effects on terrestrial and freshwater ecosystems in the United States, and to estimate associated empirical N critical loads, defined as the input of a pollutant below which no detrimental ecological effects occur over the long-term according to present knowledge.

TL;DR: Empirical critical loads for N deposition effects and maps showing areas projected to be in exceedance of the critical load (CL) are given for seven major vegetation types in California, showing decreases in N deposition are needed for long-term ecosystem protection and sustainability.

TL;DR: Because of their importance in ecosystems and their value in environmental assessment, there is a large and growing interest among natural historians, land managers, and foresters in these organisms.

TL;DR: In this paper, the authors evaluated the effects of probabilistic and non-probabilistic sample surveys on resultant classification tree models for predicting the presence of four lichen species in the Pacific Northwest, USA.