Biogeochemical cycling in forest soils of the eastern Sierra Nevada Mountains, USA

Johnson, Dale W.; Miller, W. W.; Susfalk, R. B.; Murphy, James D.; Dahlgren, Randy A.; Glass, Dallas W.

doi:10.1016/j.foreco.2009.01.018

Cited by 30 publications

(29 citation statements)

References 67 publications

(99 reference statements)

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“…same sampling plots, replications, etc.) as were used in previous studies for biomass, C, and N stock quantification (Johnson et al, 1997(Johnson et al, , 2001(Johnson et al, , 2005Murphy et al, 2006) to be able to scale up Hg concentrations to ecosystem-level pools (see below). Samples were taken in 4 replicate plots in each site (with the exception of 3 replicate plots in the Little Valley intact site), and 3 random locations within each replicate plot were sampled for one pooled sample per plot; i.e.…”

Section: Sample Collection For Measurement Of Hg C and N Mass Ratiomentioning

confidence: 99%

Mercury concentrations and pools in four Sierra Nevada forest sites, and relationships to organic carbon and nitrogen

2009

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Abstract. This study presents data on mercury (Hg) concentrations, stochiometric relations to carbon (C) and nitrogen (N), and Hg pool sizes in four Sierra Nevada forest sites of similar exposure and precipitation regimes, and hence similar atmospheric deposition, to evaluate how ecosystem parameters control Hg retention in ecosystems. In all four sites, the largest amounts of Hg reside in soils which account for 94-98% of ecosystem pools. Hg concentrations and Hg/C ratios increase in the following order: Green Needles/Leaves

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Section: Sample Collection For Measurement Of Hg C and N Mass Ratiomentioning

confidence: 99%

Mercury concentrations and pools in four Sierra Nevada forest sites, and relationships to organic carbon and nitrogen

2009

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“…Current conditions tend to sequester nutrients into the organic biomass, both living and dead, leading to the buildup of large nutrient pools of N and P in the vegetation and forest floor. At the same time large forest floor N and P pools may also contribute to increases in inorganic N and P pools in the summer dry O horizon [38][39][40][41]. Accumulating water soluble nutrients may leach into the soil or discharge from the area of by way of overland flow surface runoff and/or litter interflow [21,37].…”

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A Synthesis of Sierran Forest Biomass Management Studies and Potential Effects on Water Quality

Miller

Johnson

Karam

et al. 2010

Forests

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Abstract:The Lake Tahoe basin, located along the California and Nevada border between the Carson and Sierra Nevada mountain ranges, represents a complex forested ecosystem consisting of numerous sub-watersheds and tributaries that discharge directly to Lake Tahoe. This synthesis focuses on historical and current nutrient pools and the effects of biomass management in watersheds of the basin relative to their potential impacts on nutrient (N, P) related discharge water quality. An accumulating forest floor as a result of fire suppression has resulted in the build-up of large nutrient pools that now provide a -natural‖ source of long term nutrient availability to surface waters. As a consequence, stand and forest floor replacing wildfire may cause a large magnitude nutrient mobilization impact on runoff water quality. Hence, mechanical harvest and controlled burning have become popular management strategies. The most ecologically significant long-term effects of controlled fire appear to be the loss of C and N from the forest floor. Although the application of controlled fire may have some initial impact on overland/litter interflow nutrient loading, controlled burning in conjunction with mechanical harvest has the potential to improve runoff water quality by reducing N and P discharge and improving the overall health of forest ecosystems without the danger of a high intensity wildfire.

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“…In particular, populations can have a “memory” of antecedent climatic events such that the effect can be retained for several years, or effects may compound across years and amplify (Schwinning et al 2004). Changes in the magnitude and duration of the snowpack are also likely to have important effects on soil nutrient dynamics due to altered rates of transformation and/or release (Groffman et al 2001; Johnson et al 2009). During the 2 years of detailed demography, we performed limited soil nutrient analyses (Griffith 2010).…”

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confidence: 99%

Effects of climate and snow depth on Bromus tectorum population dynamics at high elevation

Griffith

Loik

2010

Oecologia

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Invasive plants are thought to be especially capable of range shifts or expansion in response to climate change due to high dispersal and colonization abilities. Although highly invasive throughout the Intermountain West, the presence and impact of the grass Bromus tectorum has been limited at higher elevations in the eastern Sierra Nevada, potentially due to extreme wintertime conditions. However, climate models project an upward elevational shift of climate regimes in the Sierra Nevada that could favor B. tectorum expansion. This research specifically examined the effects of experimental snow depth manipulations and interannual climate variability over 5 years on B. tectorum populations at high elevation (2,175 m). Experimentally-increased snow depth had an effect on phenology and biomass, but no effect on individual fecundity. Instead an experimentally-increased snowpack inhibited population growth in 1 year by reducing seedling emergence and early survival. A similar negative effect of increased snow was observed 2 years later. However, a strong negative effect on B. tectorum was also associated with a naturally low-snow winter, when seedling emergence was reduced by 86%. Across 5 years, winters with greater snow cover and a slower accumulation of degree-days coincided with higher B. tectorum seedling density and population growth. Thus, we observed negative effects associated with both experimentally-increased and naturally-decreased snowpacks. It is likely that the effect of snow at high elevation is nonlinear and differs from lower elevations where wintertime germination can be favorable. Additionally, we observed a doubling of population size in 1 year, which is alarming at this elevation.Electronic supplementary materialThe online version of this article (doi:10.1007/s00442-010-1749-3) contains supplementary material, which is available to authorized users.

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Biogeochemical cycling in forest soils of the eastern Sierra Nevada Mountains, USA

Cited by 30 publications

References 67 publications

Mercury concentrations and pools in four Sierra Nevada forest sites, and relationships to organic carbon and nitrogen

Mercury concentrations and pools in four Sierra Nevada forest sites, and relationships to organic carbon and nitrogen

A Synthesis of Sierran Forest Biomass Management Studies and Potential Effects on Water Quality

Effects of climate and snow depth on Bromus tectorum population dynamics at high elevation

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