Regional Gradients in Lichen Communities of the Southeast United States

Analyzing lichen indicator data in the Forest Inventory and Analysis Program

“…For example, similar numbers of macrolichen species and vascular plant species are found in Abies grandis forests in western Montana (Lesica et al 1991). In a typical southeastern forest, 20 to 60 lichen species are recorded in a single FIA plot sample (McCune et al 1997b). Lichens play numerous functional roles in temperate forest ecosystems (Nash 2008), including significant N-fixation and nutrient cycling (Pike 1978) and serving as forage for mammals and arthropods (Dawson et al 1987;Maser et al 1985Maser et al , 1986Rominger and Oldemeyer 1989;Servheen and Lyon 1989;Sharnoff and Rosentreter 2008).…”

“…This field protocol was developed specifically for large-scale forest monitoring in the United States (McCune 2000, McCune et al 1997b. Tradeoffs in design of sample protocols for lichens must be accepted to achieve project goals efficiently (McCune 2000;McCune and Grace 2002;Will-Wolf 1988;Will-Wolf et al 2002b, 2004.…”

“…Each lichen response gradient defined for a model must be statistically independent of all other lichen response gradients defined for that particular model. Developers demonstrate that response indexes for lichen gradients are independent of local factors such as stand age, total tree basal area, and percentage of basal area in conifers or hardwoods (Geiser and Neitlich 2007;McCune 2005, 2006;McCune et al 1997b). Each model includes procedures for estimating goodness-of-fit of a plot to a model.…”

“…The FIA lichen indicator protocol enables tracking of response to air pollution and other major environmental factors across regions in a scientifically valid and cost-effective manner (McCune et al 1997a(McCune et al , 1997bWillWolf et al 2006). This comes at the expense of obtaining data too coarse for assessing response to within-plot variables such as lichen substrate or microhabitat and tree species composition (Dietrich and Scheidegger 1997, McCune 2000, WillWolf et al 2004 veloping a lichen gradient model are presented in detail in Will-Wolf and Neitlich (2010), and are summarized here.…”

Red Maple, <em>Acer rubrum</em>, Wetland Composition and Structure in Nova Scotia

“…Differences (or similarities) between communities are calculated and then plotted in such a way that the distances between sites are maximally correlated with ecological distances. NMDS is one of the most robust methods of multivariate analysis (McCune et al 1997;McCune et al 1998;Neitlich et al 2003). Barbour et al (1999) compared four ordination techniques using tree species composition with a priori known differences.…”