Mineral Cycling and Epiphytic Lichens: Implications at the Ecosystem Level

Abstract

The nutrient contribution of lichens as litterfall in forests is discussed for a number of different ecosystems and it is hypothesized that lichens are important in capturing nutrients from wet deposition, occult precipitation, sedimentation, impaction and gaseous uptake. Most nutrients captured by these processes represent new nutrient inputs that would otherwise not be intercepted by the ecosystem. Part of these nutrients will be incorporated into lichen biomass and only become available upon death and decomposition, but a portion will be leached by precipitation and become deposited on the soil surface. Although quantifying nutrient sources, fluxes and pool sizes is a potentially complex task, we describe a simplified approach for determining whether lichens significantly affect the mineral cycling of a forest. Preliminary results for an oak woodland in California document that epiphytic lichens may reduce throughfall and alter throughfall chemistry.

Effects of nitrogen deposition and empirical nitrogen critical loads for ecoregions of the United States

“…Dominant regional oligotrophs (e.g., Alectoria, Bryoria, Lobaria, Ramalina, Usnea) comprise the bulk of lichen biomass in old-growth forests, contribute to nutrient cycling through N 2 fixation, and are used for nesting material, essential winter forage for rodents and ungulates, and invertebrate habitat (McCune and Geiser 2009). Storage of water and atmospheric nutrients by these lichen genera and epiphytic bryophytes moderates humidity and provides a slow-release system of essential plant nutrients to the soil (Boonpragob et al 1989, Knops et al 1991, Pypker 2004, Cornelissen et al 2007). In the tundra, lichens and bryophytes represent a significant portion of the biomass, and reindeer lichens are a vital link in the short arctic food chain (Kyto¨viita and Crittenden 2007).…”

Assessment of Nitrogen deposition effects and empirical critical loads of Nitrogen for ecoregions of the United States

“…Dominant regional oligotrophs (e.g., Alectoria, Bryoria, Lobaria, Ramalina, Usnea) comprise the bulk of lichen biomass in old-growth forests, contribute to nutrient cycling through N 2 fi xation, and are used for nesting material, essential winter forage for rodents and ungulates, and invertebrate habitat (McCune and Geiser 2009). Storage of water and atmospheric nutrients by these lichen genera and epiphytic bryophytes moderates humidity and provides a slow release system of essential plant nutrients to the soil (Boonpragob et al 1989, Cornelissen et al 2007, Knops et al 1991, Pypker 2004). In the tundra, lichens and bryophytes represent a signifi cant portion of the biomass, and reindeer lichens are a vital link in the short arctic food chain (Kytöviita and Crittenden 2007).…”

From a tree to a stand in Finnish boreal forests: Biomass estimation and comparison of methods

“…For instance, epiphytic lichens are important as a winter food source for reindeer and caribou (Andreev 1954, Ahti 1959, Edwards et al 1960, Scotter 1963, Scotter 1964) and as food and shelter for some small animals (Ahti 1977, Gerson & Seaward 1977. Epiphytic lichens also influence nutrient cycling (Knops et al 1991(Knops et al , 1996 as they absorb nutrients from the substrata and intercept dry and wet deposits from the air. They also modify the quantity and quality of throughfall and stem flow.…”