Litter decomposition and nutrient turnover in three ecosystem types of the coastal western hemlock biogeoclimatic zone

Jennifer Barbara De Catanzaro
Rates of litter decomposition, nutrient release, and total forest floor turnover were measured on two replicates of three ecosystem types in the Coastal Western Hemlock Zone of British Columbia, in an attempt to establish whether or not ecosystem types could be differentiated on the basis of functional parameters. Litter bags of two mesh sizes and leaf tethering were used to compare weight losses and nutrient dynamics of specific litter components. The dry weight losses of conifer needles
more » ... nifer needles confined in 1 mm mesh bags ranged from 30 to 40 % after one year. There was no significant difference between sites, Weight loss of salal leaves on xeric sites ranged from 20 % after one year for samples confined in 1 mm mesh bags to 45 % for tethered leaf samples. Big-leaf maple weight loss ranged from 15% for samples confined in 1 mm mesh bags to 60 % for tethered samples. Twig samples lost 7 to 21 % of their weight on all sites after six months, with slightly higher values occurring on the hygric sites, Cellulose strips in 4 mm mesh bags lost an average of 23 % of their weight on the-xeric, 21 % on the mesic, and 40 % on the hygric sites. Nutrient mass and concentration changes over one year varied somewhat between different types of foliage litter. The total mass of K, Mg, and Ca decreased in all litter types on all sites, N and P mass changes were more variable, The relative mobility of nutrients released from decomposing conifer litter was Ca> Mg?P>K>N, and from broad-leaf litter was Ca>Mg>K>P>N. The low mobility of K was concluded to be due to leaching of this element from the litter prior to its collection for the study. Numbers of fauna in the forest floor were compared on one replicate of each of the ecosystem types at six week intervals throughout the year. Micro-fauna were more abundant on the xeric and mesic sites, while macro- and meso-fauna were more numerous on the hygric sites. Numbers were lowest on all sites when forest floor moisture was lowest in August. At other times of the year pop [...]
doi:10.14288/1.0100225 fatcat:iq3jmbxoqvag5knzfxhw47i2om