Nitrogen and Fungi
A cornerstone of my research has been to use field experiments to investigate the impacts of elevated nitrogen on fungi, especially mycorrhizal fungi. In brief, my studies have shown that nitrogen addition decreases mycorrhizal fungal diversity and shifts community composition. How these changes impact their roles in ecosystems remains a key question as well as understanding recovery of fungal communities from nitrogen addition.
To address recovery questions, investigations at Bear Brook Watershed Experiment in Maine (BBWM) are in progress.
To date, I have investigated these questions using experimental nitrogen additions in field settings and across a range of terrestrial ecosystems including
Savannas
Avis, P.G., McLaughlin D.J., Dentinger B.C., and Reich P.B. 2003. Long-term increase in nitrogen supply alters above and below ground ectomycorrhizal communities and increases the dominance of Russula spp. in a temperate oak savanna. New Phytologist 160: 239-253.
Avis P.G. and I. D. Charvat. 2005. The response of ectomycorrhizal fungal inoculum to long-term increases in nitrogen supply. Mycologia 97(2): 329-337.
Norris M, Avis PG, Hobbie S, Reich P. 2013. Positive feed-backs between decomposition and soil nitrogen availability along soil N gradients. Plant and Soil. 367(1-2):347 – 361
Forests
Corbin J.C., Avis P.G., and Wilbur R. 2003. Effect of phosphorus addition on nitrogen cycling and arbuscular mycorrhizal inoculum potential in a nitrogen limited forest ecosystem. Environmental Air, Water and Soil Pollution 147:141-161.
Avis P.G., G.M. Mueller and J. Lussenhop. 2008. Ectomycorrhizal fungal communities in two North American oak forests respond to nitrogen addition. New Phytologist 179:472-483.
Parrent J., Peay K., Arnold A.E., Comas L., Avis P.G., Tuininga A. 2010. Moving from pattern to process in fungal symbioses: linking functional traits, community ecology and phylogenetics. New Phytologist 185: 882-886.
Andrew, C., Mueller, G.M., Avis, P.G. 2022. Do local-scale context dependencies shape how ectomycorrhizal fungal diversity structures with reduced or sustained experimental N addition? Pedobiologia, doi.org/10.1016/j.pedobi.2022.150791.