Hotspots of Epiphytic Lichen Diversity in Two Young Managed Forests

Abstract

Understanding within‐stand variation in diversity of epiphytes will provide an improved basis for producing timber while conserving biological diversity. Two 80‐ha, 50–year–old managed stands of conifers were surveyed to locate 0.4 ha putative “diversity” plots, the areas appearing most diverse in lichen epiphytes. These plots were generally located in areas made heterogeneous by canopy gaps, wolf trees (trees with large‐diameter lower branches), and old‐growth remnant trees. “Matrix” plots, in contrast, were chosen at random from the remaining, more homogenous forest. Diversity plots hosted from 25% to 40% more epiphytic lichen species than matrix plots in both stands. The strongest within‐stand gradients in species composition were correlated with percentage of plot occupied by gaps and wolf trees. Percentage of the plot in gaps was correlated with species richness (r = 0.79). In the more structurally diverse stand, diversity and abundance of nitrogen‐fixing “cyanolichens” were correlated with percentage of the plot occupied by gaps (0.5 < r < 0.9), and alectorioid lichens were correlated with percentage of the plot occupied by old‐growth remnant trees (0.5 < r < 0.6). In the stand with more homogenous structure, percentage of the plot under gaps was correlated with regionally common species that were otherwise absent or sparse in the matrix. Protecting gaps, hardwoods, wolf trees, and old‐growth remnant trees during thinning or other partial cutting is likely to promote the majority of epiphytic macrolichens in young conifer forests. Because these features are easily recognized on aerial photos and on the ground by land managers, it is practical to manage for forest structures that would promote lichen diversity.

Relative growth rates of two epiphytic lichens, Lobaria pulmonaria and Hypogymnia occidentalis, transplanted within and outside of Populus dripzones

“…These gradients create a range of lichendominated species-rich epiphytic communities in boreal and temperate forests. Such epiphytic vegetation types constitute a highly diverse and potentially vulnerable part of the biota of vast forest regions (Lesica et al 1991;Goward 1994;Neitlich & McCune 1996). One declining species-rich epiphytic vegetation type is the Lobarion community dominated by large and spectacular cephalodial and cyanobacterial foliose lichens (Rose 1988).…”

Riparian alder ecosystems as epiphytic lichen refugia in sub-boreal spruce forests of British Columbia

“…We know from previous studies that old-growth coniferous forest stands in these landscapes can support rich canopy lichen communities (Campbell and Fredeen 2004;Radies and Coxson 2004). Little information is known about the development of canopy lichen communities within riparian forests in these landscapes, although previous studies in the northwestern United States have shown that hardwoods can support diverse epiphyte communities (Neitlich and McCune 1997;Peterson and McCune 2003), particularly in areas adjacent to streams and rivers (McCune et al 2002).…”

The importance of host tree age, size and growth rate as determinants of epiphytic lichen diversity in boreal spruce forests

“…from the landscape scale and upwards, it has recently been shown that lichen diversity is correlated with climate, pollution and geographically related variables such as latitude and elevation (Will-Wolf et al 2006). On finer spatial scales, forest stand variables such as stand age and tree species composition become more important (Holien 1998;Hyvärinen et al 1992;Will-Wolf et al 2006;Neitlich and McCune 1997). On the scale of the single tree, variables like tree species, branch quality, bark texture, tree size and tree age have been shown to significantly explain variation in epiphytic species composition and diversity (Holien 1997;Kuusinen 1996;Gauslaa et al 1998;Löbel et al 2006;Fritz et al 2009).…”