Effects of feathermoss removal, thinning and fertilization on lodgepole pine growth, soil microclimate and stand nitrogen dynamics

Startsev, N. A.; Lieffers, Victor J.; McNabb, D. H.

doi:10.1016/j.foreco.2006.12.010

Cited by 30 publications

(30 citation statements)

References 30 publications

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“…This corresponds well with our Wnding that the cover of P. schreberi decreased both in the snow removal treatment and in the increased insulation treatment. P. schreberi dominates the moss layer in many boreal forests and not only in our study (Startsev et al 2007). An experimental removal of insulation provided by this species results in increased summer soil temperature and a prolonged snow-free period, yet leading to a decreased minimum winter temperature of the soil, especially when accompanied by shallow snow cover (Startsev et al 2007).…”

Section: Discussionsupporting

confidence: 64%

Absence of snow cover reduces understory plant cover and alters plant community composition in boreal forests

2011

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Snow regimes affect biogeochemistry of boreal ecosystems and are altered by climate change. The effects on plant communities, however, are largely unexplored despite their influence on relevant processes. Here, the impact of snow cover on understory community composition and below-ground production in a boreal Picea abies forest was investigated using a long-term (8-year) snow cover manipulation experiment consisting of the treatments: snow removal, increased insulation (styrofoam pellets), and control. The snow removal treatment caused longer (118 vs. 57 days) and deeper soil frost (mean minimum temperature -5.5 vs. -2.2°C) at 10 cm soil depth in comparison to control. Understory species composition was strongly altered by the snow cover manipulations; vegetation cover declined by more than 50% in the snow removal treatment. In particular, the dominant dwarf shrub Vaccinium myrtillus (-82%) and the most abundant mosses Pleurozium schreberi (-74%) and Dicranum scoparium (-60%) declined strongly. The C:N ratio in V. myrtillus leaves and plant available N in the soil indicated no altered nitrogen nutrition. Fine-root biomass in summer, however, was negatively affected by the reduced snow cover (-50%). Observed effects are attributed to direct frost damage of roots and/ or shoots. Besides the obvious relevance of winter processes on plant ecology and distribution, we propose that shifts in the vegetation caused by frost damage may be an important driver of the reported alterations in biogeochemistry in response to altered snow cover. Understory plant performance clearly needs to be considered in the biogeochemistry of boreal systems in the face of climate change.

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Section: Discussionsupporting

confidence: 64%

Absence of snow cover reduces understory plant cover and alters plant community composition in boreal forests

2011

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“…Vascular plants may beneWt mosses by generating a favourable microclimate, as has been suggested for both grassland and woodland (Ingerpuu et al 2005;Startsev et al 2007). More frequent, however, are accounts of negative relationships between vascular plant and moss biomass, reXecting suppressed moss growth through leaf litter deposition and shading, despite mosses having a generally low light compensation point (Bergamini et al 2001;Malmer et al 2003, Van der Wal et al 2005Startsev et al 2008).…”

Section: Introductionmentioning

confidence: 85%

“…Mosses may also ameliorate autumn and winter severity by providing an insulating layer which can buVer soil against low temperatures and protect vascular plants from frost damage (Gornall et al 2007;Startsev et al 2007). Maintaining warmer soils in winter may aVect over-winter nutrient dynamics, which, in turn, can have an impact upon growing season productivity (Chapin et al 2002).…”

Section: Positive Impacts Of Mossesmentioning

confidence: 99%

“…Conversely, mosses provide a habitat for N-Wxing cyanobacteria that play a critical role in the N cycle of arctic environments (Solheim et al 1996). Mosses may prevent frost damage to roots (Sohlberg and Bliss 1987;Olofsson et al 2001;Startsev et al 2007) and also provide shelter, a factor often cited as the mechanism behind positive plant interactions (Callaghan and Emanuelsson 1985;Carlsson and Callaghan 1991). Their growth form both aids moisture retention and enhances boundary layer resistance (Sveinbjornsson and Oechel 1992), reducing the desiccating impacts of strong arctic winds.…”

Section: Introductionmentioning

confidence: 99%

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Balancing positive and negative plant interactions: how mosses structure vascular plant communities

et al. 2011

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Our understanding of positive and negative plant interactions is primarily based on vascular plants, as is the prediction that facilitative effects dominate in harsh environments. It remains unclear whether this understanding is also applicable to moss-vascular plant interactions, which are likely to be influential in low-temperature environments with extensive moss ground cover such as boreal forest and arctic tundra. In a field experiment in high-arctic tundra, we investigated positive and negative impacts of the moss layer on vascular plants. Ramets of the shrub Salix polaris, herb Bistorta vivipara, grass Alopecurus borealis and rush Luzula confusa were transplanted into plots manipulated to contain bare soil, shallow moss (3 cm) and deep moss (6 cm) and harvested after three growing seasons. The moss layer had both positive and negative impacts upon vascular plant growth, the relative extent of which varied among vascular plant species. Deep moss cover reduced soil temperature and nitrogen availability, and this was reflected in reduced graminoid productivity. Shrub and herb biomass were greatest in shallow moss, where soil moisture also appeared to be highest. The relative importance of the mechanisms by which moss may influence vascular plants, through effects on soil temperature, moisture and nitrogen availability, was investigated in a phytotron growth experiment. Soil temperature, and not nutrient availability, determined Alopecurus growth, whereas Salix only responded to increased temperature if soil nitrogen was also increased. We propose a conceptual model showing the relative importance of positive and negative influences of the moss mat on vascular plants along a gradient of moss depth and illustrate species-specific outcomes. Our findings suggest that, through their strong influence on the soil environment, mat-forming mosses structure the composition of vascular plant communities. Thus, for plant interaction theory to be widely applicable to extreme environments such as the Arctic, growth forms other than vascular plants should be considered.

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“…Downregulation of their N 2 -fixation activity has the potential to off-set atmospheric N r inputs, and thereby 'buffer' the supply of N to primary production [5,6]. Additionally, bryophytes thermally insulate underlying soils [7] and produce litter that is highly recalcitrant [8], which collectively diminish soil C and N mineralization rates [4]. Changes in bryophyte biomass in response to N r deposition therefore have the potential to cause soil C losses, while inversely coupling above-ground responses by influencing N mineralization and availability to vascular plants [4].…”

Section: Introductionmentioning

confidence: 99%

The impact of simulated chronic nitrogen deposition on the biomass and N ₂ -fixation activity of two boreal feather moss–cyanobacteria associations

2013

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Bryophytes achieve substantial biomass and play several key functional roles in boreal forests that can influence how carbon (C) and nitrogen (N) cycling respond to atmospheric deposition of reactive nitrogen (N r ). They associate with cyanobacteria that fix atmospheric N 2 , and downregulation of this process may offset anthropogenic N r inputs to boreal systems. Bryophytes also promote soil C accumulation by thermally insulating soils, and changes in their biomass influence soil C dynamics. Using a unique large-scale (0.1 ha forested plots), long-term experiment (16 years) in northern Sweden where we simulated anthropogenic N r deposition, we measured the biomass and N 2 -fixation response of two bryophyte species, the feather mosses Hylocomium splendens and Pleurozium schreberi. Our data show that the biomass declined for both species; however, N 2 -fixation rates per unit mass and per unit area declined only for H. splendens. The low and high treatments resulted in a 29% and 54% reduction in total feather moss biomass, and a 58% and 97% reduction in total N 2 -fixation rate per unit area, respectively. These results help to quantify the sensitivity of feather moss biomass and N 2 fixation to chronic N r deposition, which is relevant for modelling ecosystem C and N balances in boreal ecosystems.

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Effects of feathermoss removal, thinning and fertilization on lodgepole pine growth, soil microclimate and stand nitrogen dynamics

Cited by 30 publications

References 30 publications

Absence of snow cover reduces understory plant cover and alters plant community composition in boreal forests

Absence of snow cover reduces understory plant cover and alters plant community composition in boreal forests

Balancing positive and negative plant interactions: how mosses structure vascular plant communities

The impact of simulated chronic nitrogen deposition on the biomass and N ₂ -fixation activity of two boreal feather moss–cyanobacteria associations

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Effects of feathermoss removal, thinning and fertilization on lodgepole pine growth, soil microclimate and stand nitrogen dynamics

Cited by 30 publications

References 30 publications

Absence of snow cover reduces understory plant cover and alters plant community composition in boreal forests

Absence of snow cover reduces understory plant cover and alters plant community composition in boreal forests

Balancing positive and negative plant interactions: how mosses structure vascular plant communities

The impact of simulated chronic nitrogen deposition on the biomass and N 2 -fixation activity of two boreal feather moss–cyanobacteria associations

Contact Info

Product

Resources

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The impact of simulated chronic nitrogen deposition on the biomass and N ₂ -fixation activity of two boreal feather moss–cyanobacteria associations