BG2-2: Because key species and functional groups play a dominant role in biogeochemical processes and ecosystem response to disturbance, boreal forest C and N balances are vulnerable to changes in their growth characteristics and abundance.
Methods for Mosses
To better understand how changes in the abundance and productivity of mosses will affect ecosystem carbon and nutrient
dynamics, our goal is to develop predictive relationships between environmental
variation and moss biomass, production, and nutrient turnover. We will document % cover of mosses and other
cryptogams in all of the LTER permanent plots, in the newly established
extensive black spruce sites, and in the low level fertilization
experiments. Moss % cover will be estimated with a digital imaging system (J. W. Harden personal communication)
in permanent subplots located within each larger plot. Images will be taken every three years (in
years 2 and 5 of this funding cycle) to determine changes in % cover, which is
likely to change rapidly in disturbed and newly fertilized sites. In paired plots, we will measure N content
and apical growth (NPP) of the dominant species. Apical growth will be estimated with a fluorescent dye method
followed by a destructive harvest (Russell 1988), and N content will be measured on harvested
samples. We will combine % cover, NPP and N concentration estimates to calculate stocks and fluxes of C and N in
mosses. We will relate the latter to stand-level characteristics, including vascular species composition (% cover),
biomass and productivity, and physical environment (light, air and soil
temperatures, maximum depth of thaw, relative humidity, depth of water table
[floodplain only], and throughfall).
Literature cited:
Russell, S. 1988. Measurements of bryophyte growth 1. Biomass (harvest) techniques. In Glime, J. M.
(ed) Methods in Bryology. Proceedings of the Bryological Methods Workshop, Mainz.Pp. 249-257. Hattori Botanical
Labroatory, Nichinan.