Pattern and vegetation–environment relationships in a boreal forested wetland in northeastern Ontario

Jeglum, John K.; He, Feng

doi:10.1139/b95-067

Cited by 45 publications

(41 citation statements)

References 7 publications

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“…Gower and Richards (1990) argued that larches do well in nutrient-poor peatlands because they have advantages in nitrogen retranslocation and mechanical effi ciency. But these advantages do not explain regular shifts in dominance from selman 1963, Glaser et al 1981, 1990, Wright et al 1992, Wisconsin (Montague and Givnish 1996), and Ontario (Vitt andBayley 1984, Jeglum andHe 1995) have shown that Larix laricina replaces Picea mariana in moving from extremely infertile, ombrotrophic bogs to more fertile, minerotrophic fens. Even more remarkably, in some extremely rich fens, dominance reverts to Picea or Thuja (Fig.…”

Section: Effects Of Climatic Seasonalitymentioning

confidence: 99%

Adaptive significance of evergreen vs. deciduous leaves: solving the triple paradox

2002

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Patterns in the dominance of evergreen vs. deciduous plants have long interested ecologists, biogeographers, and global modellers. But previous models to account for these patterns have signifi cant weaknesses. Bottom-up, mechanistic models -based on physiology, competition, and natural selection -have often been non-quantitative or restricted to a small range of habitats, and almost all have ignored belowground costs and whole-plant integration. Top-down, ecosystem-based models have succeeded in quantitatively reproducing several patterns, but rely partly on empirically derived constants and thresholds that lack a mechanistic explanation. It is generally recognized that seasonal drought can favor deciduous leaves, and that infertile soils can favor long-lived evergreen leaves. But no model has yet explained three great paradoxes, involving dominance by 1) evergreens in highly seasonal, boreal forests, 2) deciduous larch in many nutrient-poor peatlands, and 3) evergreen leaf-exchangers in nutrient-poor subtropical forests, even though they shed their leaves just as frequently as deciduous species. This paper outlines a generalized optimality model to account for these and other patterns in leaf longevity and phenology, based on maximizing whole-plant carbon gain or height growth, and building on recent advances in our understanding of the quantitative relationships of leaf photosynthesis, nitrogen content, and mass per unit area to leaf life-span. Only a whole-plant approach can explain evergreen dominance under realistic ecological conditions, or account for the boreal paradox, the larch paradox, the leaf-exchanger paradox, and expected shifts in shade tolerance associated with leaf phenology. Poor soils favor evergreens not merely by increasing the costs of nutrient acquisition, but also by depressing the maximum rate of photosynthesis and thus the seasonal contrast in photosynthetic return between leaves adapted to favorable vs. unfavorable conditions. The dominance of evergreens in western North America beyond the coastal zone of mild winters and winter rainfall appears related to the unusually long photosynthetic season for evergreen vs. deciduous plants there. Future models for optimal leaf phenology must incorporate differences between evergreen and deciduous plants in allocation to photosynthetic vs. non-photosynthetic tissue, rooting depth, stem allometry, xylem anatomy, and exposure to herbivores and leaching, and analyze how these differences interact with the photosynthetic rate, transpiration, and nutrient demands of leaves with different life-spans to affect rates of height growth in specifi c microsites.

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Section: Effects Of Climatic Seasonalitymentioning

confidence: 99%

Adaptive significance of evergreen vs. deciduous leaves: solving the triple paradox

2002

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“…Many mires show a clear zonation of Sphagnum species along environmental gradients (e.g., Andrus et al 1982, Clymo and Hayward 1982, Baaren et al 1988, Vitt and Chee 1990, Jeglum and He 1995. One of tile factors that determines the distribution of Sphagnum species within a mire is water availability in the habitat.…”

Section: Introductionmentioning

confidence: 99%

“…Recent studies by Vitt and Chee (1990) and Jeglum and He (1995) analyzed the relationship between mire vegetation components and chemical properties of water using detrended correspondence analysis or canonical correspondence analysis. Vitt and Chee (1990) clarified that the bryophyte component changes along a gradient from extreme-rich to poor fens, and the gradient correlates with pH, specific conductivity, and concentration of elements (calcium, magnesium, sodium, and potassium).…”

Section: Introductionmentioning

confidence: 99%

“…Vitt and Chee (1990) clarified that the bryophyte component changes along a gradient from extreme-rich to poor fens, and the gradient correlates with pH, specific conductivity, and concentration of elements (calcium, magnesium, sodium, and potassium). Jeglum and He (1995) showed that the pH-calcium gradient is one of the main factors that correlates with mire plant distribution, including Sphagnum spp.…”

Section: Introductionmentioning

confidence: 99%

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Effect of pH on photosynthesis of fiveSphagnum species in mires in Ochiishi, northern Japan

Haraguchi

1996

Wetlands

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In a laboratory experiment, the pH dependence of photosynthesis was investigated for five Sphagnum species: S. fuscum. S. magellanicum, S. girgensohnii, S squarrosum and S. falfax, that are common in mires in Ochiishi, northern Japan, The maximum photosynthetic rate of S. fuscum occurred at the lowest pH among the species. The photosynthetic rate of S. girgensohniL S. squarrosum and S. fallax varied little between pH 5.2 and pH 7.5, whereas the photosynthetic rate of S. fuscum and S, magellanicum tended to decline as pH increased. The results indicate that S, fuscum is most adapted to acidic conditions, while S. girgensohnii, S. squarrosum and 5'. fallax are adapted to a wide pH range of ambient waters.

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“…However, the ecological factors explaining this gradient are complex and vary from site to site [5,8]. Locally, secondary gradients such as peat thickness or shading may also be important, especially for bryophytes [9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Environmental factors explaining the vegetation patterns in a temperate peatland

Pellerin

Lagneau

Lavoie

et al. 2009

Comptes Rendus. Biologies

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Although ombrotrophic temperate peatlands are important ecosystems for maintaining biodiversity in eastern North America, the environmental factors influencing their flora are only partly understood. The relationships between plant species distribution and environmental factors were thus studied within the oldest temperate peatland of Québec. Plant assemblages were identified by cluster analysis while CCA was used to related vegetation gradients to

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Pattern and vegetation–environment relationships in a boreal forested wetland in northeastern Ontario

Cited by 45 publications

References 7 publications

Adaptive significance of evergreen vs. deciduous leaves: solving the triple paradox

Adaptive significance of evergreen vs. deciduous leaves: solving the triple paradox

Effect of pH on photosynthesis of fiveSphagnum species in mires in Ochiishi, northern Japan

Environmental factors explaining the vegetation patterns in a temperate peatland

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