Fine-scale vegetation distribution in a cool temperate peatland

2006 ◽  
Vol 84 (6) ◽  
pp. 910-923 ◽  
Author(s):  
Jill L. Bubier ◽  
Tim R. Moore ◽  
Gareth Crosby

Carbon (C) modeling and carbon dioxide (CO2) flux measurements in peatlands are dependent on the distribution and productivity of vegetation in a system with a high degree of spatial variability, often linked to the position of the water table. We tested the hypothesis that at a fine-scale (tens of metres) water table position exerts a strong control on species abundance, plant biomass, particularly photosynthetically active tissues, leaf area index (LAI), and areal foliar N and chlorophyll at Mer Bleue, a cool temperate peatland in eastern Canada. Total aboveground biomass ranged from 147 to 1011 g·m–2, with shrubs contributing between 42% and 72% of the total in the transects. We found significant (P < 0.05) positive relationships between foliar and total vascular plant biomass and mean water table position, and significant decreases in the shrub foliar:woody biomass ratio and moss biomass with a lower water table. However, there was no significant relationship between water table position and photosynthetically active tissues (vascular plant leaves and moss capitulum), ranging from 114 to 672 g·m–2) and the areal mass of N in these tissues, ranging from 1.5 to 6.7 g·m–2. Multivariate analyses of vegetation and environmental data showed that species distribution could be explained by both water table and chemistry gradients and that unimodal rather than linear responses best described the species and water table relationships. LAI ranged from 0.1 to over 3 and was correlated with both water table position and with vascular foliar biomass. Percent cover of shrubs was correlated with foliar biomass and LAI. Our results suggest that the less labour-intensive estimates of percent cover can be used to predict the vascular plant foliar biomass and LAI measurements. The lack of relationship between photosynthetically active tissues, tissue N concentrations, and water table may also explain the surprising lack of spatial variability in peak growing season eddy flux net ecosystem CO2 exchange in three different areas of the peatland.

Botany ◽  
2012 ◽  
Vol 90 (1) ◽  
pp. 63-74 ◽  
Author(s):  
Anna M. Laine ◽  
Jill Bubier ◽  
Terhi Riutta ◽  
Mats B. Nilsson ◽  
Tim R. Moore ◽  
...  

We compared the amount and composition of different aboveground biomass (BM) fractions of four mires with their net ecosystem CO2exchange (NEE) measured by eddy covariance. We found clear differences in response of green biomass (GBM) of plant functional types (PFTs) to water table (WT), which resulted in larger spatial variation in GBM within a mire than variation between mires. GBM varied between mires from 126 ± 7 to 336 ± 16 g·m–2(mean ± SE), while within mire variation at largest was from 157 ± 17 to 488 ± 20 g·m–2(mean ± SE). GBM of dominant PFTs appeared to be better in explaining the peak growing season NEE than the total BM or GBM of a mire. The differences in photosynthetic capacity between PTFs had a major role, and thus a smaller GBM with different species composition could result in higher NEE than larger GBM. Vascular plant GBM, especially that of sedges, appeared to have a high impact on NEE. Eleven PFTs, defined here, appeared to capture well the internal variation within mires, and the differences in GBM between communities were explained by the water table response of PFTs. Our results suggest the use of photosynthesizing BM, separated into PFTs, in modelling ecosystem carbon exchange instead of using just total BM.


Botany ◽  
2009 ◽  
Vol 87 (9) ◽  
pp. 845-853 ◽  
Author(s):  
M. T. Murphy ◽  
A. McKinley ◽  
T. R. Moore

In wetland ecosystems, little is known about the relationships between above- and below-ground plant biomass and water table, a primary driver of their distribution in these systems. These relationships can provide a means for estimating belowground stocks over large areas with variable biomass and predicting vascular plant responses to changing water tables resulting from climate change. We measured above- and below-ground vascular plant biomass across species and microtopography (i.e., hummocks and lawns) in a bog in eastern Ontario. We examined the relationships between above- and below-ground vascular plant biomass their variation with water table and species richness. We took 56 cores during a growing season, separating above- and below-ground biomass by species and plant part (small and coarse root, leaf, stem). Hummocks had greater above- and below-ground biomass, and significantly greater aboveground:belowground ratios than lawns. Lawns had a more even distribution of biomass across species than hummocks aboveground, indicating that only a few species (e.g., Vaccinium myrtilloides Michx. and Chamaedaphne calyculata Moench) are able to thrive in the driest bog conditions. Additionally, fewer species contributed to root biomass at depth, suggesting possible resource partitioning among species. Lower water tables lead to greater belowground biomass. Total above- to below-ground plant biomass relationships were strongest when separated by plant species.


1997 ◽  
Vol 40 (2) ◽  
pp. 371-375
Author(s):  
S. O. Prasher ◽  
M. Singh ◽  
A. K. Maheshwari ◽  
R. S. Clemente

2013 ◽  
Vol 38 (1) ◽  
pp. 79-96 ◽  
Author(s):  
Jean-Nicolas Pradervand ◽  
Anne Dubuis ◽  
Loïc Pellissier ◽  
Antoine Guisan ◽  
Christophe Randin

Recent advances in remote sensing technologies have facilitated the generation of very high resolution (VHR) environmental data. Exploratory studies suggested that, if used in species distribution models (SDMs), these data should enable modelling species’ micro-habitats and allow improving predictions for fine-scale biodiversity management. In the present study, we tested the influence, in SDMs, of predictors derived from a VHR digital elevation model (DEM) by comparing the predictive power of models for 239 plant species and their assemblages fitted at six different resolutions in the Swiss Alps. We also tested whether changes of the model quality for a species is related to its functional and ecological characteristics. Refining the resolution only contributed to slight improvement of the models for more than half of the examined species, with the best results obtained at 5 m, but no significant improvement was observed, on average, across all species. Contrary to our expectations, we could not consistently correlate the changes in model performance with species characteristics such as vegetation height. Temperature, the most important variable in the SDMs across the different resolutions, did not contribute any substantial improvement. Our results suggest that improving resolution of topographic data only is not sufficient to improve SDM predictions – and therefore local management – compared to previously used resolutions (here 25 and 100 m). More effort should be dedicated now to conduct finer-scale in-situ environmental measurements (e.g. for temperature, moisture, snow) to obtain improved environmental measurements for fine-scale species mapping and management.


2014 ◽  
Vol 11 (3) ◽  
pp. 807-820 ◽  
Author(s):  
T. M. Munir ◽  
B. Xu ◽  
M. Perkins ◽  
M. Strack

Abstract. Northern peatland ecosystems represent large carbon (C) stocks that are susceptible to changes such as accelerated mineralization due to water table lowering expected under a climate change scenario. During the growing seasons (1 May to 31 October) of 2011 and 2012 we monitored CO2 fluxes and plant biomass along a microtopographic gradient (hummocks-hollows) in an undisturbed dry continental boreal treed bog (control) and a nearby site that was drained (drained) in 2001. Ten years of drainage in the bog significantly increased coverage of shrubs at hummocks and lichens at hollows. Considering measured hummock coverage and including tree incremental growth, we estimate that the control site was a sink of −92 in 2011 and −70 g C m−2 in 2012, while the drained site was a source of 27 and 23 g C m−2 over the same years. We infer that, drainage-induced changes in vegetation growth led to increased biomass to counteract a portion of soil carbon losses. These results suggest that spatial variability (microtopography) and changes in vegetation community in boreal peatlands will affect how these ecosystems respond to lowered water table potentially induced by climate change.


1999 ◽  
Vol 29 (1) ◽  
pp. 53-61 ◽  
Author(s):  
U Silins ◽  
R L Rothwell

The spatial variability of soil aeration (aerobic limit depth and oxygen diffusion rate (ODR)) among different drainage ditch spacings and at various distances from drainage ditches was examined at two peatlands drained for forestry in north-central Alberta. Drainage lowered mean water table levels (p < 0.001) at both peatlands. Lower water table levels within drained areas were associated with greater aerobic limit depths (p < 0.001) and greater ODR (p < 0.001 at Saulteaux River; p < 0.027 at Wolf Creek) compared with undrained areas of both peatlands. Spatial patterns of aerobic limit depth and ODR indicated strong spatial variability of soil aeration in the immediate vicinity of drainage ditches. However, little sensitivity of soil aeration to different ditch spacings was evident. Potential effects of post-drainage subsidence on soil aeration was evident as increased distance of both the aerobic limit, and near-zero oxygen diffusion rates above the water table surface at both peatlands. One effect of post-drainage peatland subsidence may be to increase the thickness of the capillary zone above the water table. However, reduction of aeration within the rooting zone of peatland trees due to subsidence was not observed because of low water tables within the drained areas of both peatlands.


2014 ◽  
Vol 11 (19) ◽  
pp. 5521-5537 ◽  
Author(s):  
B. Magnússon ◽  
S. H. Magnússon ◽  
E. Ólafsson ◽  
B. D. Sigurdsson

Abstract. Plant colonization and succession on the volcanic island of Surtsey, formed in 1963, have been closely followed. In 2013, a total of 69 vascular plant species had been discovered on the island; of these, 59 were present and 39 had established viable populations. Surtsey had more than twice the species of any of the comparable neighbouring islands, and all of their common species had established on Surtsey. The first colonizers were dispersed by sea, but, after 1985, bird dispersal became the principal pathway with the formation of a seagull colony on the island and consequent site amelioration. This allowed wind-dispersed species to establish after 1990. Since 2007, there has been a net loss of species on the island. A study of plant succession, soil formation and invertebrate communities in permanent plots on Surtsey and on two older neighbouring islands (plants and soil) has revealed that seabirds, through their transfer of nutrients from sea to land, are major drivers of development of these ecosystems. In the area impacted by seagulls, dense grassland swards have developed and plant cover, species richness, diversity, plant biomass and soil carbon become significantly higher than in low-impact areas, which remained relatively barren. A similar difference was found for the invertebrate fauna. After 2000, the vegetation of the oldest part of the seagull colony became increasingly dominated by long-lived, rhizomatous grasses (Festuca, Poa, Leymus) with a decline in species richness and diversity. Old grasslands of the neighbouring islands Elliđaey (puffin colony, high nutrient input) and Heimaey (no seabirds, low nutrient input) contrasted sharply. The puffin grassland of Elliđaey was very dense and species-poor. It was dominated by Festuca and Poa, and very similar to the seagull grassland developing on Surtsey. The Heimaey grassland was significantly higher in species richness and diversity, and had a more even cover of dominants (Festuca/Agrostis/Ranunculus). We forecast that, with continued erosion of Surtsey, loss of habitats and increasing impact from seabirds a lush, species-poor grassland will develop and persist, as on the old neighbouring islands.


2016 ◽  
Vol 13 (9) ◽  
pp. 2637-2651 ◽  
Author(s):  
Järvi Järveoja ◽  
Matthias Peichl ◽  
Martin Maddison ◽  
Kaido Soosaar ◽  
Kai Vellak ◽  
...  

Abstract. Peatland restoration may provide a potential after-use option to mitigate the negative climate impact of abandoned peat extraction areas; currently, however, knowledge about restoration effects on the annual balances of carbon (C) and greenhouse gas (GHG) exchanges is still limited. The aim of this study was to investigate the impact of contrasting mean water table levels (WTLs) on the annual C and GHG balances of restoration treatments with high (ResH) and low (ResL) WTL relative to an unrestored bare peat (BP) site. Measurements of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) fluxes were conducted over a full year using the closed chamber method and complemented by measurements of abiotic controls and vegetation cover. Three years following restoration, the difference in the mean WTL resulted in higher bryophyte and lower vascular plant cover in ResH relative to ResL. Consequently, greater gross primary production and autotrophic respiration associated with greater vascular plant cover were observed in ResL compared to ResH. However, the means of the measured net ecosystem CO2 exchanges (NEE) were not significantly different between ResH and ResL. Similarly, no significant differences were observed in the respective means of CH4 and N2O exchanges. In comparison to the two restored sites, greater net CO2, similar CH4 and greater N2O emissions occurred in BP. On the annual scale, ResH, ResL and BP were C sources of 111, 103 and 268 g C m−2 yr−1 and had positive GHG balances of 4.1, 3.8 and 10.2 t CO2 eq ha−1 yr−1, respectively. Thus, the different WTLs had a limited impact on the C and GHG balances in the two restored treatments 3 years following restoration. However, the C and GHG balances in ResH and ResL were considerably lower than in BP due to the large reduction in CO2 emissions. This study therefore suggests that restoration may serve as an effective method to mitigate the negative climate impacts of abandoned peat extraction areas.


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