scholarly journals Leaf and Soil δ15N Patterns Along Elevational Gradients at Both Treelines and Shrublines in Three Different Climate Zones

Forests ◽  
2019 ◽  
Vol 10 (7) ◽  
pp. 557 ◽  
Author(s):  
Xue Wang ◽  
Yong Jiang ◽  
Haiyan Ren ◽  
Fei-Hai Yu ◽  
Mai-He Li
Keyword(s):  
Temperate Forests ◽  
N Cycling ◽  
Biogeochemical Process ◽  
Subtropical Region ◽  
Elevational Gradients ◽  
Climate Zones ◽  
Upper Limits ◽  
Environmental Variations ◽  
Trees And Shrubs ◽  
Soil Δ15n

The natural abundance of stable nitrogen (N) isotope (δ15N) in plants and soils can reflect N cycling processes in ecosystems. However, we still do not fully understand patterns of plant and soil δ15N at alpine treelines and shrublines in different climate zones. We measured δ15N and N concentration in leaves of trees and shrubs and also in soils along elevational gradients from lower altitudes to the upper limits of treelines and shrublines in subtropical, dry- and wet-temperate regions in China. The patterns of leaf δ15N in trees and shrubs in response to altitude changes were consistent, with lower values occurring at higher altitude in all three climate zones, but such patterns did not exist for leaf Δδ15N and soil δ15N. Average δ15N values of leaves (−1.2‰) and soils (5.6‰) in the subtropical region were significantly higher than those in the two temperate regions (−3.4‰ and 3.2‰, respectively). Significant higher δ15N values in subtro4pical forest compared with temperate forests prove that N cycles are more open in warm regions. The different responses of leaf and soil δ15N to altitude indicate complex mechanisms of soil biogeochemical process and N sources uptake with environmental variations.

scholarly journals Soil properties determine the elevational patterns of base cations and micronutrients in plant-soil system up to the upper limits of trees and shrubs

2017 ◽  
Author(s):  
Ruzhen Wang ◽  
Xue Wang ◽  
Yong Jiang ◽  
Artemi Cerdà ◽  
Jinfei Yin ◽  
...  
Keyword(s):  
Soil Ph ◽  
Inorganic Nitrogen ◽  
Base Cations ◽  
Base Cation ◽  
Plant Tissues ◽  
Soil System ◽  
Plant Soil ◽  
Total Soil ◽  
Upper Limits ◽  
Trees And Shrubs

Abstract. To understand whether base cations and micronutrients in the plant-soil system change with elevation, we investigated the patterns of base cations and micronutrients in both soils and plant tissues along three elevational gradients and three different climate zones in China. Base cations of Ca, Mg and K and micronutrients of Fe, Mn and Zn were determined in soils, trees and shrubs growing at lower and middle elevations as well as at their upper limits on Balang (subtropical, SW China), Qilian (dry-temperate, NW China) and Changbai (wet-temperate, NE China) mountains. No consistent elevational patterns were found for base cation and micronutrient concentrations in both soils and plant tissues (leaves, roots, shoots and stem sapwood). Rather, soil pH, total soil nitrogen (TN), the soil organic carbon (SOC) to TN ratio (C:N), and total soil inorganic nitrogen (TIN) determined the elevational patterns of soil exchangeable Ca and Mg. Furthermore, multiple regression models showed that soil pH and C:N were pivotal factors affecting soil Fe, Mn and Zn availabilities. In return, soil base cation and micronutrient availabilities played fundamental roles in determining the base cation and micronutrient concentrations in plant tissues. Our results highlight the importance of soil physicochemical properties (mainly SOC, C:N and pH) rather than elevation (i.e., canopy cover and environmental factors, especially temperature), in determining base cation and micronutrient availabilities in soils and subsequently their concentrations in plant tissues.

scholarly journals Spatial relationship between δ<sup>15</sup>N and elevation in agricultural landscapes

2008 ◽  
Vol 15 (3) ◽  
pp. 397-407 ◽  
Author(s):  
A. Biswas ◽  
B. C. Si ◽  
F. L. Walley
Keyword(s):  
Spatial Variability ◽  
Negative Relationship ◽  
Spatial Relationship ◽  
Agricultural Landscapes ◽  
N Cycling ◽  
Phase Correlation ◽  
Coefficient Of Determination ◽  
Important Indicator ◽  
Wavelet Coherency ◽  
Soil Δ15n

Abstract. Understanding of the nitrogen (N) cycle and its spatial variability is important for managing ecosystems. Soil δ15N, as an important indicator of different soil nitrogen cycling processes, may provide critical information about the spatial variability in soil N cycling. The objective of this study was to examine the dominant landscape scale variability of δ15N, the location of the variability and its spatial relationship with elevation. Soil δ15N and elevation were measured along two transects (Davidson and Elstow, Saskatchewan, Canada). Each transect had 128 points with 3 m sampling intervals. Higher δ15N values typically occurred in topographic depressions as compared to knolls. The coefficient of determination revealed a significant linear relationship between δ15N and elevation (r2=0.27) at Davidson whereas no relationship (r2=0.00) was detected for the Elstow transect. However, wavelet spectra, cross wavelet, and squared wavelet coherency analysis revealed spatial relationships between δ15N and elevation at both sites. A strong coherency between δ15N and elevation at large scales (96 m or more) was detected for both transects. The Davidson transect showed an out of phase coherency at a topographically elevated area at the beginning and the end of the transect. The Elstow transect had a strong out of phase correlation (negative relationship) at the middle of the transect (corresponding to a depressions) indicating a location dependent relationship between δ15N and elevation. The relationship between δ15N and elevation reflects the effects of hydrology and soil water content over the landscape on N cycling processes.

scholarly journals Acute Myocardial Infarction Hospitalizations between Cold and Hot Seasons in an Island across Tropical and Subtropical Climate Zones—A Population-Based Study

2019 ◽  
Vol 16 (15) ◽  
pp. 2769
Author(s):  
Min-Liang Chu ◽  
Chiao-Yu Shih ◽  
Tsung-Cheng Hsieh ◽  
Han-Lin Chen ◽  
Chih-Wei Lee ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Acute Myocardial Infarction ◽  
Hospital Admissions ◽  
Cold Season ◽  
Population Based ◽  
Tropical Region ◽  
Subtropical Climate ◽  
Subtropical Region ◽  
Climate Zones ◽  
Climatic Regions

We investigated the effects of cold and hot seasons on hospital admissions for acute myocardial infarction (AMI) at the junction of tropical and subtropical climate zones. The hospitalization data of 6897 AMI patients from January 1997 to December 2011 were obtained from the database of the National Health Insurance, including date of admission, gender, age, and comorbidities of hypertension, diabetes mellitus (DM), and dyslipidemia. A comparison of AMI prevalence between seasons and the association of season-related AMI occurrences with individual variables were assessed. AMI hospitalizations in the cold season (cold-season-AMIs) were significantly greater than those in the hot season (OR 1.15; 95% CI 1.10–1.21). In the subtropical region, cold-season-AMIs were strongly and significantly associated with the ≥65 years group (OR1.28; 95% CI 1.11 to 1.48). In the tropical region, cold-season-AMIs, in association with dyslipidemia relative to non-dyslipidemia, were significantly strong in the non-DM group (OR 1.45; 95% CI 1.01 to 2.09) but weak in the DM group (OR 0.74; 95% CI 0.55 to 0.99). The cold season shows increased risks for AMI, markedly among the ≥65 years cohort in the subtropical region, and among the patients diagnosed with either DM or dyslipidemia but not both in the tropical region. Age and comorbidity of metabolic dysfunction influence the season-related incidences of AMI in different climatic regions.

Soil δ15N patterns in old-growth forests of southern Chile as integrator for N-cycling

2005 ◽  
Vol 41 (3) ◽  
pp. 249-259 ◽  
Author(s):  
Pascal Boeckx ◽  
Leandro Paulino ◽  
Carlos Oyarzún ◽  
Oswald van Cleemput ◽  
Roberto Godoy
Keyword(s):  
N Cycling ◽  
Southern Chile ◽  
Old Growth ◽  
Old Growth Forests ◽  
Soil Δ15n

scholarly journals NEW INSIGHTS CONCERNING IDENTIFICATION, MANAGEMENT AND CONSERVATION OF INDIGENOUS TREES AND SHRUBS IN THE NETHERLANDS

2021 ◽  
Vol 56 ◽  
pp. 149-167
Author(s):  
Norbertus Cornelis Maria MAES ◽  
Keyword(s):  
The Netherlands ◽  
Woody Species ◽  
Natura 2000 ◽  
Landscape Elements ◽  
Climate Zones ◽  
Indigenous Trees ◽  
Ancient Woodlands ◽  
Trees And Shrubs ◽  
Management And Conservation ◽  
Lower Rhine

In densely populated European countries like the Netherlands, old landscape elements such as ancient woodlands and ancient hedges are today rare. Owing to the introduction of exotic species and indigenous trees and shrubs imported from other climate zones, recognition of truly wild, i.e. autochthonous, individuals and populations is now problematical, posing challenges for forest management agencies, particularly at Natura 2000 sites. The author has developed a method for recognising genetically pure wild woody species, based on characteristics of the plant itself and those of the growing site. With this method, explained here, around 70% of the Netherlands has been surveyed, along with much of Flanders and part of the lower Rhine region of Germany. The results are illustrated with reference to two Dutch ancient woodlands, where new insights were obtained in terms of native status of the woody species and the ‘authenticity’ of the tree and shrub layer.

scholarly journals Stable isotope signatures of soil nitrogen on an environmental-geomorphic gradient within the Congo Basin

2020 ◽  
Author(s):  
Simon Baumgartner ◽  
Marijn Bauters ◽  
Matti Barthel ◽  
Travis William Drake ◽  
Landry Cizungu Ntaboba ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Montane Forest ◽  
Local Scale ◽  
N Cycling ◽  
Congo Basin ◽  
N Availability ◽  
Miombo Woodland ◽  
Lowland Forest ◽  
Stable Isotope Signatures ◽  
Soil Δ15n

Abstract. Nitrogen (N) availability can be highly variable in tropical forests on a regional and on a local scale. While environmental gradients influence N cycling on a regional scale, topography is known to affect N availability on a local scale. We compared stable isotope signatures (δ15N) of soil profiles in tropical lowland forest, tropical montane forest, and subtropical Miombo woodland within the Congo Basin as a proxy to assess ecosystem-level differences in N cycling. Furthermore, we examined the effect of surface slope angles on δ15N in the same forests to quantify local differences induced by topography. Soil δ15N profiles indicated that the N cycling in in the montane forest is more closed and dominated by organic N turnover, whereas the lowland forest and Miombo woodland experienced a more open N cycle dominated by inorganic N. Furthermore, our results show that slope angles only affects the soil δ15N signature in the Miombo forest, which is prone to erosion due to the lower vegetation cover and intense rainfalls at the onset of the wet season. Lowland forest, on the other hand, with a flat topography and protective vegetation cover, showed no influence of topography on soil N cycling. Values from the montane forest showed high variability in stable isotope signatures, but they were not constrained by topography. A pan-tropical analysis of soil δ15N values (i.e. from our study and the literature) reveals that soil δ15N is best explained by factors controlling erosion, namely mean annual precipitation, leaf area index, and slope angles. The erosive forces vary immensely between different tropical forest ecosystems and our results highlight the need of more spatial coverage of N-cycling studies in tropical forests, to further elucidate the local impact of topography on N cycling in this biome.

scholarly journals Nitrogen isotopic composition of plants and soil in an arid mountainous terrain: sunny slope versus shady slope

2017 ◽  
Author(s):  
Chongjuan Chen ◽  
Yufu Jia ◽  
Yuzhen Chen ◽  
Imran Mehmood ◽  
Yunting Fang ◽  
...  
Keyword(s):  
Environmental Effects ◽  
Regional Scale ◽  
Local Environment ◽  
Global Scale ◽  
Influential Factors ◽  
N Cycling ◽  
N Availability ◽  
Soil N ◽  
The Difference ◽  
Soil Δ15n

Abstract. Nitrogen cycling is tightly associated with environment. Sunny slope of a given mountain could significantly differ from shady slope in environment. Thus, N cycling should also be different between the two slopes. Since leaf δ15N, soil δ15N and △δ15Nleaf-soil (△δ15Nleaf-soil = leaf δ15N − soil δ15N) could reflect the N cycling characteristics, we put forward a hypothesis that leaf δ15N, soil δ15N and △δ15Nleaf-soil should differ across the two slopes. However, such a comparative study between two slopes has never been conducted yet. In addition, environmental effects on leaf and soil δ15N derived from studies at global scale were often found to be different from that at regional scale. This led to our argument that environmental effects on leaf and soil δ15N could depend on local environment. To confirm our hypothesis and argument, we measured leaf and soil δ15N on the sunny and shady slopes of Mount Tianshan. Remarkable environment differences between the two slopes provided an ideal opportunity for our test. The study showed that leaf δ15N, soil δ15N and △δ15Nleaf-soil on the sunny slope were greater than that on the shady slope although the difference in soil δ15N was not significant. The result confirmed our hypothesis and suggested that the sunny slope has higher soil N transformation rates and soil N availability than the shady slope. Besides, this study observed that the significant influential factors of leaf δ15N were temperature, precipitation, leaf N, leaf C / N and silt / clay ratio on the shady slope, whereas on the sunny slope only leaf C / N was related to leaf δ15N. The significant influential factors of soil δ15N were temperature, precipitation and silt / clay ratio on the shady slope, whereas on the sunny slope MAP and soil moisture exerted significant effects. Precipitation exerted contrary effects on soil δ15N between the two slopes. Thus, this study supported our argument that the relationships between leaf and soil δ15N and environmental factors are local-dependent.

scholarly journals Soil properties determine the elevational patterns of base cations and micronutrients in the plant–soil system up to the upper limits of trees and shrubs

2018 ◽  
Vol 15 (6) ◽  
pp. 1763-1774 ◽  
Author(s):  
Ruzhen Wang ◽  
Xue Wang ◽  
Yong Jiang ◽  
Artemi Cerdà ◽  
Jinfei Yin ◽  
...  
Keyword(s):  
Soil Ph ◽  
Canopy Cover ◽  
Base Cations ◽  
Base Cation ◽  
Plant Tissues ◽  
Soil Base ◽  
Soil System ◽  
Plant Soil ◽  
Upper Limits ◽  
Trees And Shrubs

Abstract. To understand whether base cations and micronutrients in the plant–soil system change with elevation, we investigated the patterns of base cations and micronutrients in both soils and plant tissues along three elevational gradients in three climate zones in China. Base cations (Ca, Mg, and K) and micronutrients (Fe, Mn, and Zn) were determined in soils, trees, and shrubs growing at lower and middle elevations as well as at their upper limits on Balang (subtropical, SW China), Qilian (dry temperate, NW China), and Changbai (wet temperate, NE China) mountains. No consistent elevational patterns were found for base cation and micronutrient concentrations in both soils and plant tissues (leaves, roots, shoots, and stem sapwood). Soil pH, soil organic carbon (SOC), total soil nitrogen (TN), the SOC to TN ratio (C : N), and soil extractable nitrogen (NO3− and NH4+) determined the elevational patterns of soil exchangeable Ca and Mg and available Fe, Mn, and Zn. However, the controlling role of soil pH and SOC was not universal as revealed by their weak correlations with soil base cations under tree canopies at the wet temperate mountain and with micronutrients under both tree and shrub canopies at the dry temperate mountain. In most cases, soil base cation and micronutrient availabilities played fundamental roles in determining the base cation and micronutrient concentrations in plant tissues. An exception existed for the decoupling of leaf K and Fe with their availabilities in the soil. Our results highlight the importance of soil physicochemical properties (mainly SOC, C : N, and pH) rather than elevation (i.e., canopy cover and environmental factors, especially temperature), in determining base cation and micronutrient availabilities in soils and subsequently their concentrations in plant tissues.

scholarly journals Stable isotope signatures of soil nitrogen on an environmental–geomorphic gradient within the Congo Basin

SOIL ◽  
2021 ◽  
Vol 7 (1) ◽  
pp. 83-94
Author(s):  
Simon Baumgartner ◽  
Marijn Bauters ◽  
Matti Barthel ◽  
Travis W. Drake ◽  
Landry C. Ntaboba ◽  
...  
Keyword(s):  
Tropical Forests ◽  
Montane Forest ◽  
N Cycling ◽  
Congo Basin ◽  
N Availability ◽  
Slope Gradient ◽  
Miombo Woodland ◽  
Lowland Forest ◽  
Stable Isotope Signatures ◽  
Soil Δ15n

Abstract. Nitrogen (N) availability can be highly variable in tropical forests on regional and local scales. While environmental gradients influence N cycling on a regional scale, topography is known to affect N availability on a local scale. We compared natural abundance of 15N isotopes of soil profiles in tropical lowland forest, tropical montane forest, and subtropical Miombo woodland within the Congo Basin as a proxy to assess ecosystem-level differences in N cycling. Soil δ15N profiles indicated that N cycling in the montane forest is relatively more closed and dominated by organic N turnover, whereas the lowland forest and Miombo woodland experienced a more open N cycle dominated by inorganic N. Furthermore, we examined the effect of slope gradient on soil δ15N within forest types to quantify local differences induced by topography. Our results show that slope gradient only affects the soil δ15N in the Miombo forest, which is prone to erosion due to a lower vegetation cover and intense rainfall at the onset of the wet season. Lowland forest, on the other hand, with a flat topography and protective vegetation cover, showed no influence of topography on soil δ15N in our study site. Despite the steep topography, slope angles do not affect soil δ15N in the montane forest, although stable isotope signatures exhibited higher variability within this ecosystem. A pan-tropical analysis of soil δ15N values (i.e., from our study and literature) reveals that soil δ15N in tropical forests is best explained by factors controlling erosion, namely mean annual precipitation, leaf area index, and slope gradient. Erosive forces vary immensely between different tropical forest ecosystems, and our results highlight the need for more spatial coverage of N cycling studies in tropical forests, to further elucidate the local impact of topography on N cycling in this biome.

scholarly journals Nitrogen input <sup>15</sup>N signatures are reflected in plant <sup>15</sup>N natural abundances in subtropical forests in China

2017 ◽  
Vol 14 (9) ◽  
pp. 2359-2370 ◽  
Author(s):  
Geshere Abdisa Gurmesa ◽  
Xiankai Lu ◽  
Per Gundersen ◽  
Yunting Fang ◽  
Qinggong Mao ◽  
...  
Keyword(s):  
Southern China ◽  
N Deposition ◽  
Pine Forest ◽  
N Cycling ◽  
N Addition ◽  
Inorganic N ◽  
Subtropical Forests ◽  
Broad Leaved Forest ◽  
Soil Δ15n ◽  
Leaved Forest

Abstract. Natural abundance of 15N (δ15N) in plants and soils can provide time-integrated information related to nitrogen (N) cycling within ecosystems, but it has not been well tested in warm and humid subtropical forests. In this study, we used ecosystem δ15N to assess effects of increased N deposition on N cycling in an old-growth broad-leaved forest and a secondary pine forest in a high-N-deposition area in southern China. We measured δ15N of inorganic N in input and output fluxes under ambient N deposition, and we measured N concentration (%N) and δ15N of major ecosystem compartments under ambient deposition and after decadal N addition at 50 kg N ha−1yr−1, which has a δ15N of −0.7 ‰. Our results showed that the total inorganic N in deposition was 15N-depleted (−10 ‰) mainly due to high input of strongly 15N-depleted NH4+-N. Plant leaves in both forests were also 15N-depleted (−4 to −6 ‰). The broad-leaved forest had higher plant and soil %N and was more 15N-enriched in most ecosystem compartments relative to the pine forest. Nitrogen addition did not significantly affect %N in the broad-leaved forest, indicating that the ecosystem pools are already N-rich. However, %N was marginally increased in pine leaves and significantly increased in understory vegetation in the pine forest. Soil δ15N was not changed significantly by the N addition in either forest. However, the N addition significantly increased the δ15N of plants toward the 15N signature of the added N, indicating incorporation of added N into plants. Thus, plant δ15N was more sensitive to ecosystem N input manipulation than %N in these subtropical forests. We interpret the depleted δ15N of plants as an imprint from the high and 15N-depleted N deposition that may dominate the effects of fractionation that are observed in most warm and humid forests. Fractionation during the steps of N cycling could explain the difference between negative δ15N in plants and positive δ15N in soils, and the increase in soil δ15N with depths. Nevertheless, interpretation of ecosystem δ15N from high-N-deposition regions needs to include data on the deposition 15N signal.

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