scholarly journals Species-specific temporal variation in photosynthesis as a moderator of peatland carbon sequestration

2017 ◽  
Vol 14 (2) ◽  
pp. 257-269 ◽  
Author(s):  
Aino Korrensalo ◽  
Pavel Alekseychik ◽  
Tomáš Hájek ◽  
Janne Rinne ◽  
Timo Vesala ◽  
...  
Keyword(s):  
Leaf Area ◽  
Vascular Plants ◽  
Gross Primary Production ◽  
Light Response ◽  
Growing Season ◽  
Photosynthetic Parameters ◽  
Gross Photosynthesis ◽  
Ecosystem Level ◽  
Species Specific ◽  
Photosynthetic Properties

Abstract. In boreal bogs plant species are low in number, but they differ greatly in their growth forms and photosynthetic properties. We assessed how ecosystem carbon (C) sink dynamics were affected by seasonal variations in the photosynthetic rate and leaf area of different species. Photosynthetic properties (light response parameters), leaf area development and areal cover (abundance) of the species were used to quantify species-specific net and gross photosynthesis rates (PN and PG, respectively), which were summed to express ecosystem-level PN and PG. The ecosystem-level PG was compared with a gross primary production (GPP) estimate derived from eddy covariance (EC) measurements.Species areal cover, rather than differences in photosynthetic properties, determined the species with the highest PG of both vascular plants and Sphagna. Species-specific contributions to the ecosystem PG varied over the growing season, which, in turn, determined the seasonal variation in ecosystem PG. The upscaled growing season PG estimate, 230 g C m−2, agreed well with the GPP estimated by the EC (243 g C m−2).Sphagna were superior to vascular plants in ecosystem-level PG throughout the growing season but had a lower PN. PN results indicated that areal cover of the species, together with their differences in photosynthetic parameters, shape the ecosystem-level C balance. Species with low areal cover but high photosynthetic efficiency appear to be potentially important for the ecosystem C sink. Results imply that functional diversity, i.e., the presence of plant groups with different seasonal timing and efficiency of photosynthesis, may increase the stability of C sinks of boreal bogs.

scholarly journals Species-specific temporal variation in photosynthesis as a moderator of peatland carbon sequestration

2016 ◽  
Author(s):  
Aino Korrensalo ◽  
Tomáš Hájek ◽  
Pavel Alekseychik ◽  
Janne Rinne ◽  
Timo Vesala ◽  
...  
Keyword(s):  
Leaf Area ◽  
Vascular Plants ◽  
Gross Primary Production ◽  
Light Response ◽  
Growing Season ◽  
Photosynthetic Parameters ◽  
Gross Photosynthesis ◽  
Ecosystem Level ◽  
Species Specific ◽  
Photosynthetic Properties

Abstract. In boreal bogs plant species are low in number, but they differ greatly in their growth forms and photosynthetic properties. We assessed how ecosystem carbon (C) sink dynamics were affected by seasonal variations in photosynthetic rate and leaf area of different species. Photosynthetic properties (light-response parameters), leaf area development and areal cover (abundance) of the species were used to quantify species-specific net and gross photosynthesis rates (PN and PG, respectively), which were summed to express ecosystem-level PN and PG. The ecosystem-level PG was compared with a gross primary production (GPP) estimate derived from eddy covariance measurements (EC). Species areal cover rather than differences in photosynthetic properties determined the species with the highest PG of both vascular plants and Sphagna. Species-specific contributions to the ecosystem PG varied over the growing season, which in turn determined the seasonal variation in ecosystem PG. The upscaled growing-season PG estimate, 230 g C m−2, agreed well with the GPP estimated by the EC, 243 g C m−2. Sphagna were superior to vascular plants in ecosystem-level PG throughout the growing season but had a lower PN. PN results indicated that areal cover of the species together with their differences in photosynthetic parameters shape the ecosystem-level C balance. Species with low areal cover but high photosynthetic efficiency appear to be potentially important for the ecosystem C sink. Results imply that functional diversity may increase the stability of C sink of boreal bogs.

Variation in photosynthetic properties among bog plants

Botany ◽  
2016 ◽  
Vol 94 (12) ◽  
pp. 1127-1139 ◽  
Author(s):  
Aino Korrensalo ◽  
Tomáš Hájek ◽  
Timo Vesala ◽  
Lauri Mehtätalo ◽  
Eeva-Stiina Tuittila
Keyword(s):  
Plant Species ◽  
Vascular Plants ◽  
Physiological State ◽  
Vascular Plant ◽  
Principal Component ◽  
Light Response ◽  
Gross Photosynthesis ◽  
Interspecific Differences ◽  
Photosynthetic Properties ◽  
Number Of Plant Species

Plant functional types (PFTs) are used to make generalizations in modeling how plants impact ecosystem functioning. In boreal bogs the number of plant species is small, but several PFTs are represented, namely sedges, deciduous and evergreen dwarf-shrubs, as well as hummock, lawn, and hollow Sphagna. Despite the use of PFTs in modeling, the value of PFTs to describe the photosynthetic properties of bog plants has not been systematically studied. We aim to quantify the photosynthetic properties of typical bog plant species and assess how well PFT divisions reflect differences among species. We measured photosynthetic light response and physiological state of photosystem II of 19 species, monthly, over a growing season. Differences were assessed using principal component analysis and mixed models. Photosynthetic properties separated Sphagna into traditional PFTs, of which hollow species had the highest gross photosynthesis. Sphagnum photosynthesis had large seasonal variation, as monthly differences exceeded those among PFTs or species. The photosynthetic properties of vascular plants differed widely among species but did not follow traditional PFTs. Vascular plant seasonal changes were of less importance than interspecific differences. The results justify using PFTs to describe the ability of bog Sphagna to bind carbon, but do not justify the same approach for vascular plants.

Estimating photosynthetic light-use efficiency using the photochemical reflectance index: variations among species

2004 ◽  
Vol 31 (3) ◽  
pp. 255 ◽  
Author(s):  
Jianmin Guo ◽  
Craig M. Trotter
Keyword(s):  
Light Response ◽  
Species Group ◽  
Photosynthetic Parameters ◽  
Co2 Uptake ◽  
Light Use Efficiency ◽  
Photochemical Reflectance Index ◽  
Response Data ◽  
Use Efficiency ◽  
Species Specific ◽  
The Relationship

Recent studies have shown that the photochemical reflectance index (PRI), derived from narrow waveband reflectance at 531 and 570 nm, can be used as a remote measure of photosynthetic light-use efficiency (LUE). However, uncertainty remains as to the consistency of the relationship between PRI and LUE across species. In this study we examined the relationship between the PRI and various photosynthetic parameters for a group of species with varying photosynthetic capacity. At constant irradiance, for the species group as a whole, the PRI was well correlated with LUE (r2=0.58) and with several other photosynthetic parameters, but best correlated with the ratio of carotenoids to chlorophylls contents (Caro / Chl). Despite the interspecific trends observed, determination of light response functions for the PRI in relation to photosynthetic parameters revealed that species-specific relationships were clearly stronger. For example, r2>0.90 for species-level PRI / LUE relationships. Also, the species-specific light-response data show that the magnitude of the PRI can be related to the magnitude of the saturated irradiance and the rate of CO2 uptake. As demonstrated here, a light response function provides a simple yet precise approach for characterising the relationship between the PRI and photosynthetic parameters, which should assist with improved evaluation of the usefulness of the PRI as a generalised measure of LUE.

scholarly journals A bottom-up quantification of foliar mercury uptake fluxes across Europe

2020 ◽  
Vol 17 (24) ◽  
pp. 6441-6456 ◽  
Author(s):  
Lena Wohlgemuth ◽  
Stefan Osterwalder ◽  
Carl Joseph ◽  
Ansgar Kahmen ◽  
Günter Hoch ◽  
...  
Keyword(s):  
Leaf Area ◽  
Tree Species ◽  
Growing Season ◽  
Deposition Flux ◽  
Foliar Uptake ◽  
Bottom Up ◽  
Needle Age ◽  
Uptake Rates ◽  
Mercury Uptake ◽  
Species Specific

Abstract. The exchange of gaseous elemental mercury, Hg(0), between the atmosphere and terrestrial surfaces remains poorly understood mainly due to difficulties in measuring net Hg(0) fluxes on the ecosystem scale. Emerging evidence suggests foliar uptake of atmospheric Hg(0) to be a major deposition pathway to terrestrial surfaces. Here, we present a bottom-up approach to calculate Hg(0) uptake fluxes to aboveground foliage by combining foliar Hg uptake rates normalized to leaf area with species-specific leaf area indices. This bottom-up approach incorporates systematic variations in crown height and needle age. We analyzed Hg content in 583 foliage samples from six tree species at 10 European forested research sites along a latitudinal gradient from Switzerland to northern Finland over the course of the 2018 growing season. Foliar Hg concentrations increased over time in all six tree species at all sites. We found that foliar Hg uptake rates normalized to leaf area were highest at the top of the tree crown. Foliar Hg uptake rates decreased with needle age of multiyear-old conifers (spruce and pine). Average species-specific foliar Hg uptake fluxes during the 2018 growing season were 18 ± 3 µg Hg m−2 for beech, 26 ± 5 µg Hg m−2 for oak, 4 ± 1 µg Hg m−2 for pine and 11 ± 1 µg Hg m−2 for spruce. For comparison, the average Hg(II) wet deposition flux measured at 5 of the 10 research sites during the same period was 2.3 ± 0.3 µg Hg m−2, which was 4 times lower than the site-averaged foliar uptake flux of 10 ± 3 µg Hg m−2. Scaling up site-specific foliar uptake rates to the forested area of Europe resulted in a total foliar Hg uptake flux of approximately 20 ± 3 Mg during the 2018 growing season. Considering that the same flux applies to the global land area of temperate forests, we estimate a foliar Hg uptake flux of 108 ± 18 Mg. Our data indicate that foliar Hg uptake is a major deposition pathway to terrestrial surfaces in Europe. The bottom-up approach provides a promising method to quantify foliar Hg uptake fluxes on an ecosystem scale.

A bottom up approach to quantify foliar uptake of gaseous elemental mercury by European forests during the 2018 growing season

2020 ◽  
Author(s):  
Lena Wohlgemuth ◽  
Stefan Osterwalder ◽  
Günter Hoch ◽  
Christine Alewell ◽  
Martin Jiskra
Keyword(s):  
Leaf Area ◽  
Tree Species ◽  
Elemental Mercury ◽  
Growing Season ◽  
Accumulation Rates ◽  
Bottom Up ◽  
Deposition Fluxes ◽  
Gaseous Elemental Mercury ◽  
Species Specific ◽  
Hg Accumulation

<p>The deposition of gaseous elemental mercury, Hg(0), from the atmosphere to terrestrial surfaces remains poorly understood mainly due to difficulties in measuring net Hg(0) fluxes on the ecosystem scale. However, there is emerging evidence that vegetation uptake of atmospheric Hg(0) represents a major deposition pathway to terrestrial surfaces. We will present a novel bottom up approach to calculate Hg(0) deposition fluxes to aboveground foliage by combining foliar Hg accumulation rates on the basis of leaf area with species-specific leaf area indices. We analyzed Hg content in 583 foliage samples from major tree species at 10 European forested research sites along a latitudinal gradient from Switzerland to Northern Finland over the course of the 2018 growing season. Foliar Hg concentrations increased over time in all tree species at all sites. We found that foliar Hg accumulation rates normalized to leaf area increased with crown height and decreased with the age of multi-year old needles. We did not detect a clear latitudinal gradient in foliar Hg accumulation rates.</p><p>On an ecosystem scale we developed a simple bottom up approach for foliar Hg(0) uptake considering the systematic variations in crown height, needle age and tree species. We calculated species-specific average foliar Hg(0) dry deposition rates for the 2018 growing season of 22 ± 4 µg Hg m<sup>-2</sup> for beech, 16 ± 8 µg Hg m<sup>-2</sup> for oak, 3 ± 0.4 µg Hg m<sup>-2</sup> for birch, 18 ± 10 µg Hg m<sup>-2</sup> for spruce and 8 ± 4 µg Hg m<sup>-2</sup> for pine. For comparison, the average Hg wet deposition flux measured at 4 of our 10 research sites during the same time period was 2.5 ± 0.2 µg Hg m<sup>-2</sup>.</p><p>Scaling up site-specific deposition rates to the forested area of Europe (EU28) resulted in a total aboveground Hg(0) deposition to foliage of approximately 20 Mg during the 2018 growing season. Our results confirm that vegetation uptake of atmospheric Hg(0) represents a major deposition pathway to terrestrial surfaces. The bottom up approach we used is a promising method to quantify Hg(0) deposition fluxes based on easy-to-do Hg concentration measurements in foliage.</p>

scholarly journals A bottom-up quantification of foliar mercury uptake fluxes across Europe

2020 ◽  
Author(s):  
Lena Wohlgemuth ◽  
Stefan Osterwalder ◽  
Carl Joseph ◽  
Ansgar Kahmen ◽  
Günter Hoch ◽  
...  
Keyword(s):  
Leaf Area ◽  
Tree Species ◽  
Growing Season ◽  
Deposition Flux ◽  
Foliar Uptake ◽  
Bottom Up ◽  
Needle Age ◽  
Uptake Rates ◽  
Mercury Uptake ◽  
Species Specific

Abstract. The exchange of gaseous elemental mercury, Hg(0), between the atmosphere and terrestrial surfaces remains poorly understood mainly due to difficulties in measuring net Hg(0) fluxes on the ecosystem scale. Emerging evidence suggests foliar uptake of atmospheric Hg(0) to be a major deposition pathway to terrestrial surfaces. Here, we present a bottom-up approach to calculate Hg(0) uptake fluxes to aboveground foliage by combining foliar Hg uptake rates normalized to leaf area with species-specific leaf area indices. This bottom-up approach incorporates systematic variations in crown height and needle age. We analyzed Hg content in 583 foliage samples from six tree species at 10 European forested research sites along a latitudinal gradient from Switzerland to Northern Finland over the course of the 2018 growing season. Foliar Hg concentrations increased over time in all six tree species at all sites. We found that foliar Hg uptake rates normalized to leaf area were highest at the top of the tree crown. Foliar Hg uptake rates decreased with needle age of multi-year old conifers (spruce and pine). Average species-specific foliar Hg uptake fluxes during the 2018 growing season were 18 ± 3 µg Hg m−2 for beech, 26 ± 5 µg Hg m−2 for oak, 4 ± 1 µg Hg m−2 for pine and 11 ± 1 µg Hg m−2 for spruce. For comparison, the average Hg(II) wet deposition flux measured at 5 of the 10 research sites during the same period was 2.3 ± 0.3 µg Hg m−2, which was four times lower than the site-averaged foliar uptake flux of 10 ± 3 µg Hg m−2. Scaling up site-specific foliar uptake rates to the forested area of Europe resulted in a total foliar Hg uptake flux of approximately 20 ± 3 Mg during the 2018 growing season. Considering that the same flux applies to the global land area of temperate forests, we estimate a foliar Hg uptake flux of 108 ± 18 Mg. Our data indicate that foliar Hg uptake is a major deposition pathway to terrestrial surfaces in Europe. The bottom up approach provides a promising method to quantify foliar Hg uptake fluxes on an ecosystem scale.

scholarly journals Analogy-Based Crop Yield Forecasts Based on Temporal Similarity of Leaf Area Index

2021 ◽  
Vol 13 (16) ◽  
pp. 3069
Author(s):  
Yadong Liu ◽  
Junhwan Kim ◽  
David H. Fleisher ◽  
Kwang Soo Kim
Keyword(s):  
Time Series ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Crop Yield ◽  
Satellite Data ◽  
Growing Season ◽  
Environmental Data ◽  
Area Index ◽  
Current Season ◽  
Wide Range

Seasonal forecasts of crop yield are important components for agricultural policy decisions and farmer planning. A wide range of input data are often needed to forecast crop yield in a region where sophisticated approaches such as machine learning and process-based models are used. This requires considerable effort for data preparation in addition to identifying data sources. Here, we propose a simpler approach called the Analogy Based Crop-yield (ABC) forecast scheme to make timely and accurate prediction of regional crop yield using a minimum set of inputs. In the ABC method, a growing season from a prior long-term period, e.g., 10 years, is first identified as analogous to the current season by the use of a similarity index based on the time series leaf area index (LAI) patterns. Crop yield in the given growing season is then forecasted using the weighted yield average reported in the analogous seasons for the area of interest. The ABC approach was used to predict corn and soybean yields in the Midwestern U.S. at the county level for the period of 2017–2019. The MOD15A2H, which is a satellite data product for LAI, was used to compile inputs. The mean absolute percentage error (MAPE) of crop yield forecasts was <10% for corn and soybean in each growing season when the time series of LAI from the day of year 89 to 209 was used as inputs to the ABC approach. The prediction error for the ABC approach was comparable to results from a deep neural network model that relied on soil and weather data as well as satellite data in a previous study. These results indicate that the ABC approach allowed for crop yield forecast with a lead-time of at least two months before harvest. In particular, the ABC scheme would be useful for regions where crop yield forecasts are limited by availability of reliable environmental data.

scholarly journals Can vegetation index track the interannual variation in gross primary production of temperate deciduous forests?

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Fan Liu ◽  
Chuankuan Wang ◽  
Xingchang Wang
Keyword(s):  
Primary Production ◽  
Vegetation Index ◽  
Near Infrared ◽  
Deciduous Forest ◽  
Gross Primary Production ◽  
Growing Season ◽  
Temperate Deciduous Forest ◽  
Near Infrared Reflectance ◽  
Modis Ndvi ◽  
Temperate Deciduous

Abstract Background Vegetation indices (VIs) by remote sensing are widely used as simple proxies of the gross primary production (GPP) of vegetation, but their performances in capturing the inter-annual variation (IAV) in GPP remain uncertain. Methods We evaluated the performances of various VIs in tracking the IAV in GPP estimated by eddy covariance in a temperate deciduous forest of Northeast China. The VIs assessed included the normalized difference vegetation index (NDVI), the enhanced vegetation index (EVI), and the near-infrared reflectance of vegetation (NIRv) obtained from tower-radiometers (broadband) and the Moderate Resolution Imaging Spectroradiometer (MODIS), respectively. Results We found that 25%–35% amplitude of the broadband EVI tracked the start of growing season derived by GPP (R2: 0.56–0.60, bias < 4 d), while 45% (or 50%) amplitudes of broadband (or MODIS) NDVI represented the end of growing season estimated by GPP (R2: 0.58–0.67, bias < 3 d). However, all the VIs failed to characterize the summer peaks of GPP. The growing-season integrals but not averaged values of the broadband NDVI, MODIS NIRv and EVI were robust surrogates of the IAV in GPP (R2: 0.40–0.67). Conclusion These findings illustrate that specific VIs are effective only to capture the GPP phenology but not the GPP peak, while the integral VIs have the potential to mirror the IAV in GPP.

Response of wildlife to forest herbicide applications in northern coniferous ecosystems

1993 ◽  
Vol 23 (10) ◽  
pp. 2286-2299 ◽  
Author(s):  
R.A. Lautenschlager
Keyword(s):  
Small Mammal ◽  
Growing Season ◽  
Sampling Techniques ◽  
Mammal Species ◽  
Growing Seasons ◽  
Disturbed Areas ◽  
Herbicide Treatments ◽  
Species Specific ◽  
Small Mammal Species ◽  
Coniferous Ecosystems

Reviewed studies of the effects of forest herbicide applications on wildlife often lacked replication, pretreatment information, and (or) were conducted for only one or two growing seasons after treatment. Because of these problems, as well as the use of dissimilar sampling techniques, study conclusions have sometimes been contradictory. A review of eight studies of the effects of herbicide treatments on northern songbird populations in regenerating clearcuts indicates that total songbird populations are seldom reduced during the growing season after treatment. Densities of species that use early successional brushy, deciduous cover are sometimes reduced, while densities of species which commonly use more open areas, sometimes increase. A review of 14 studies of the effects of herbicide treatments on small mammals indicates that like songbirds, small mammal responses are species specific. Some species are unaffected, while some select and others avoid herbicide-treated areas. Only studies that use kill or removal trapping to study small mammal responses show density reductions associated with herbicide treatment. It seems that some small mammal species may be reluctant to venture into disturbed areas, although residents in those areas are apparently not affected by the disturbance. Fourteen relevant studies examined the effects of conifer release treatments on moose and deer foods and habitat use. Conifer release treatments reduce the availability of moose browse for as long as four growing seasons after treatment. The degree of reduction during the growing season after treatment varies with the herbicide and rate used. Deer use of treated areas remains unchanged or increases during the first growing season after treatment. Eight years after treating a naturally regenerated spruce–fir stand browse was three to seven times more abundant on treated than on control plots (depending on the chemical and rate used). Forage quality (nitrogen, ash, and moisture) of crop trees increased one growing season after the soil-active herbicide simazine was applied to control competition around outplanted 3-year-old balsam fir seedlings.

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