Epiphytic macrolichens in relation to forest management and topography in a western Oregon watershed

This dissertation describes patterns in epiphytic macrolichen community composition, diversity, and biomass across various stand types in the Blue River watershed of western Oregon. It first examines the relative importance of ecological factors such as stand age, remnant tree retention, and topography to lichen communities in the landscape. It then develops models for estimating epiphytic macrolichen biomass and uses these models to assess potential impacts of forest management strategies on future lichen biomass in the watershed. Epiphytic macrolichen communities were sampled in 117 coniferous stands in uplands and riparian areas. Stands were typed by stand age (young, 200 yrs) and by the degree of remnant tree retention (older trees that survived the most recent disturbance). Lichen biomass (oven-dried, kg/ha) was estimated for three functional groups: nitrogen-fixing cyanolichens, forage lichens, and matrix lichens in 63 of the 117 stands. Elevation was the leading factor related to differences in macrolichen communities and biomass. Cyanolichens (dominated by Lobaria oregana) were largely limited to lower elevations and were most abundant in old growth (median 1,377 kg/ha). Lichen community composition changed with stand age. Remnant presence was related only to lichen community differences in young stands. Lichen biomass increased with stand age and with remnant retention. Stands along perennial streams were cyanolichen hotspots compared to uplands. Lichen biomass was unrelated to uplands and riparian areas. Regression models estimating lichen biomass by functional group were developed from topography, stand structure, and lichen communities. The model for cyanolichen biomass had the strongest predictive power (R²= 0.85), whereas models for forage and matrix lichen biomass were less powerful (R² = 0.55 and R² = 0.58, respectively). We estimated cyanolichen and forage lichen biomass in the present watershed and forecasted lichen biomass in 200 yrs for two different management scenarios: the Landscape Plan (LP) and the Northwest Forest Plan (NWFP). Under both scenarios, lichen biomass was predicted to increase substantially from current levels due to increased remnant tree retention and the elimination of clear-cutting. The LP scenario yielded 12% higher forage lichen biomass and 8% higher cyanolichen biomass than the NWFP

Trends in spatial patterns of heavy metal deposition on national park service lands along the Red Dog Mine haul road, Alaska, 2001–2006

<div><p>Spatial patterns of Zn, Pb and Cd deposition in Cape Krusenstern National Monument (CAKR), Alaska, adjacent to the Red Dog Mine haul road, were characterized in 2001 and 2006 using <i>Hylocomium</i> moss tissue as a biomonitor. Elevated concentrations of Cd, Pb, and Zn in moss tissue decreased logarithmically away from the haul road and the marine port. The metals concentrations in the two years were compared using Bayesian posterior predictions on a new sampling grid to which both data sets were fit. Posterior predictions were simulated 200 times both on a coarse grid of 2,357 points and by distance-based strata including subsets of these points. Compared to 2001, Zn and Pb concentrations in 2006 were 31 to 54% lower in the 3 sampling strata closest to the haul road (0–100, 100–2000 and 2000–4000 m). Pb decreased by 40% in the stratum 4,000–5,000 m from the haul road. Cd decreased significantly by 38% immediately adjacent to the road (0–100m), had an 89% probability of a small decrease 100–2000 m from the road, and showed moderate probabilities (56–71%) for increase at greater distances. There was no significant change over time (with probabilities all ≤ 85%) for any of the 3 elements in more distant reference areas (40–60 km). As in 2001, elemental concentrations in 2006 were higher on the north side of the road. Reductions in deposition have followed a large investment in infrastructure to control fugitive dust escapement at the mine and port sites, operational controls, and road dust mitigation. Fugitive dust escapement, while much reduced, is still resulting in elevated concentrations of Zn, Pb and Cd out to 5,000 m from the haul road. Zn and Pb levels were slightly above arctic baseline values in southern CAKR reference areas.</p></div

Modeled 2006 Zn moss tissue concentrations along the DMTS.

<p>The 2.5^th and 97.5^th percentiles (lower and upper bound of the 95% interval) of the modeled concentrations are shown at right. Dots on the main graph are sized proportionally in four classes by the quartile distributions of the reciprocal of the CV.</p

Stratified sampling design for Bayesian posterior predictions prediction grid.

<p>Stratified sampling design for Bayesian posterior predictions prediction grid.</p

Percent change in Pb concentrations, 2001–2006.

<p>Percent change between 2001 and 2006 Pb moss tissue concentrations along the DMTS. The 2.5^th and 97.5^th percentiles (lower and upper bound of the 95% interval) of the modeled concentrations are shown at right. Dots on the main graph are sized proportionally in four classes by the quartile distributions of the reciprocal of the CV.</p

Prediction grid used to model the contaminant concentrations from sample points shown in Fig 2.

<p>Upper right panel shows an example of a close up view of the DMTS haul road with portions of strata 1, 2 and 3.</p

Probability of Cd decrease, 2001–2006.

<p>Probability of decrease between 2001 and 2006 Cd moss tissue concentrations based on the percentage of negative values of change among the 200 iterations at each prediction point.</p

Number of plots by distance from the DMTS haul road in 2006 sampling.

<p>Number of plots by distance from the DMTS haul road in 2006 sampling.</p

Probability of Pb decrease, 2001–2006.

<p>Probability of decrease between 2001 and 2006 Pb moss tissue concentrations based on the percentage of negative values of change among the 200 iterations at each prediction point.</p

Modeled concentrations (mg/kg dry weight) of Cd in <i>Hylocomium splendens</i> moss tissue in 2001 and 2006, average change, percent change, and probability of decrease for 5 strata.

<p>Modeled concentrations (mg/kg dry weight) of Cd in <i>Hylocomium splendens</i> moss tissue in 2001 and 2006, average change, percent change, and probability of decrease for 5 strata.</p