Regional patterns of 15N natural abundance in forest ecosystems along a large transect in eastern China

Sheng, Wenping; Yu, Guirui; Fang, Huajun; Liu, Yingchun; Wang, Qiufeng; Chen, Zhi; Zhang, Li

doi:10.1038/srep04249

Cited by 26 publications

(17 citation statements)

References 42 publications

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“…The significant variation in leaf δ 15 N of up to 3% among understory and tree species in both control and N-plots (Figures 1a and 3a) confirmed our first and second hypotheses that leaf δ 15 N would significantly vary among the co-occurring plant species under both ambient and decadal N addition. The species variation in leaf δ 15 N observed at our study site is within the range (0-10% ) often observed among co-occurring plant species [57], and it is consistent with results reported from some forests in southeastern Asia [49,50,58]. Given that the range of variation in plant δ 15 N observed at a particular site increases with the number of plant species sampled [59], the narrow species variation observed for few plant species (dominant ones that are found in all replicate plots) at our site may not indicate a general pattern in tropical forests.…”

Section: Species Variation In δ 15 N and Its Response To N And 15 N Asupporting

confidence: 91%

Species Differences in Nitrogen Acquisition in Humid Subtropical Forest Inferred From 15N Natural Abundance and Its Response to Tracer Addition

Gurmesa

Gundersen

et al. 2019

Forests

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Differences in nitrogen (N) acquisition patterns between plant species are often reflected in the natural 15N isotope ratios (δ15N) of the plant tissues, however, such differences are poorly understood for co-occurring plants in tropical and subtropical forests. To evaluate species variation in N acquisition traits, we measured leaf N concentration (%N) and δ15N in tree and understory plant species under ambient N deposition (control) and after a decade of N addition at 50 kg N ha−1 yr−1 (N-plots) in an old-growth subtropical forest in southern China. We also measured changes in leaf δ15N after one-year of 15N addition in both the control and N-plots. The results show consistent significant species variation in leaf %N in both control and N-plots, but decadal N addition did not significantly affect leaf %N. Leaf δ15N values were also significantly different among the plant species both in tree and understory layers, and both in control and N-plots, suggesting differences in N acquisition strategies such as variation in N sources and dominant forms of N uptake and dependence on mycorrhizal associations among the co-occurring plant species. Significant differences between the plant species (in both control and N-plots) in changes in leaf δ15N after 15N addition were observed only in the understory plants, indicating difference in access (or use) of deposited N among the plants. Decadal N addition had species-dependent effects on leaf δ15N, suggesting the N acquisition patterns of these plant species are differently affected by N deposition. These results suggest that co-occurring plants in N-rich and subtropical forests vary in their N acquisition traits; these differences need to be accounted for when evaluating the impact of N deposition on N cycling in these ecosystems.

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Section: Species Variation In δ 15 N and Its Response To N And 15 N Asupporting

confidence: 91%

Species Differences in Nitrogen Acquisition in Humid Subtropical Forest Inferred From 15N Natural Abundance and Its Response to Tracer Addition

Gurmesa

Gundersen

et al. 2019

Forests

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“…), if considerable fractionation upon its uptake occurred as the reported δ 15 N values for wet NH 4 + and NO 3 − deposition in rural areas (−3·4‰) and forests (−0·8‰) (Hobbie, Macko & Shugart ; Sheng et al . ) are too 15 N‐enriched to explain the measured δ 15 N values otherwise. More studies are needed to resolve the potential fractionations that occur during the uptake of N by soil‐foraging wood‐decay fungi.…”

Section: Discussionmentioning

confidence: 90%

“…Although several other studies have reported horizontally and vertically extensive mycelial cord systems (Thompson 1984;Boddy & Watkinson 1995), the other potential soil compartments for N scavenging have such high d 15 N values (from À2Á67& of humus to 1Á59& of mineral soil) that substantial isotopic fractionation would be required to explain the measured trend in wood d 15 N. If major 15 N fractionation during creation of transfer compounds (Hobbie & Hogberg 2012) by wood-decay fungal species occurs, other sources of soil N would also be plausible. Such sources could also include anthropogenic N deposition (Bebber et al 2011), if considerable fractionation upon its uptake occurred as the reported d 15 N values for wet NH 4 + and NO 3 À deposition in rural areas (À3Á4&) and forests (À0Á8&) (Hobbie, Macko & Shugart 1999;Sheng et al 2014) are too 15 N-enriched to explain the measured d 15 N values otherwise. More studies are needed to resolve the potential fractionations that occur during the uptake of N by soil-foraging wood-decay fungi.…”

Section: N 2 F I X a T I O Nmentioning

confidence: 99%

Accumulation rates and sources of external nitrogen in decaying wood in a Norway spruce dominated forest

Rinne

Rajala²,

Peltoniemi

et al. 2016

Functional Ecology

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Summary Microbial respiration in dead wood contributes substantially to the long‐lived forest carbon (C) pool and has a significant role in the forest nitrogen (N) cycle. Wood N content has been found to increase during the decay process; however, temporal dynamics and the sources of this external N remain unclear. To examine N dynamics at various stages of decomposition, we combined high variety of analytical methods on Norway spruce logs, including wood δ15N, N%, 14C‐dating, fungal composition and N2 fixation rate. For N2 fixation rate, we also determined its dependency on ambient temperature and decay class, when estimating annual N2 fixation rates for our study site. N2 fixation was observed to have a major role in increasing wood N content during decay. For the most decayed wood, it accounted for 60% of the total N accumulation. Compared to other reports, where the annual temperature was similar to our site, the calculated annual fixation rate of 85 g N ha−1 year−1 is a low estimate. However, previous studies have not taken appropriately into account the dependency of N2 fixation rate on ambient temperature and decay class. Our δ15N model describing the sources of external N, statistical analysis and the fungal DNA composition of decayed wood suggest that other sources of external N accumulating in wood were soil‐foraging wood‐decay fungi and mycorrhizal fungi. Our study improves knowledge of the temporal dynamics of N accumulation in wood with advancing wood decay, the potential sources of external N and their relative significance. All of these factors are important for nitrogen as well as carbon models dealing with ecosystem responses to climate change.

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“…Most of the published works consistently suggested that leaf δ 15 N increased with increasing mean annual temperature (MAT) and decreasing mean annual precipitation (MAP) at large regional or global scales (Austin and Sala, 1999;Amundson et al, 2003;Craine et al, 2009). However, in contrast to the commonly reported patterns, leaf δ 15 N was found to be negatively related to MAT in some Asian regions, e.g., in Inner Mongolian (Cheng et al, 2009) and eastern China (Sheng et al, 2014). Relative to plant δ 15 N, soil δ 15 N has been little addressed.…”

Section: Introductionmentioning

confidence: 82%

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

Chen¹,

Jia²,

Chen³

et al. 2017

Preprint

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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 &#948;15N, soil &#948;15N and &#9651;&#948;15Nleaf-soil (&#9651;&#948;15Nleaf-soil&#8201;=&#8201;leaf &#948;15N&#8201;&#8722;&#8201;soil &#948;15N) could reflect the N cycling characteristics, we put forward a hypothesis that leaf &#948;15N, soil &#948;15N and &#9651;&#948;15Nleaf-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 &#948;15N 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 &#948;15N could depend on local environment. To confirm our hypothesis and argument, we measured leaf and soil &#948;15N 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 &#948;15N, soil &#948;15N and &#9651;&#948;15Nleaf-soil on the sunny slope were greater than that on the shady slope although the difference in soil &#948;15N 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 &#948;15N were temperature, precipitation, leaf N, leaf C&#8201;/&#8201;N and silt&#8201;/&#8201;clay ratio on the shady slope, whereas on the sunny slope only leaf C&#8201;/&#8201;N was related to leaf &#948;15N. The significant influential factors of soil &#948;15N were temperature, precipitation and silt&#8201;/&#8201;clay ratio on the shady slope, whereas on the sunny slope MAP and soil moisture exerted significant effects. Precipitation exerted contrary effects on soil &#948;15N between the two slopes. Thus, this study supported our argument that the relationships between leaf and soil &#948;15N and environmental factors are local-dependent.

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Regional patterns of 15N natural abundance in forest ecosystems along a large transect in eastern China

Cited by 26 publications

References 42 publications

Species Differences in Nitrogen Acquisition in Humid Subtropical Forest Inferred From 15N Natural Abundance and Its Response to Tracer Addition

Species Differences in Nitrogen Acquisition in Humid Subtropical Forest Inferred From 15N Natural Abundance and Its Response to Tracer Addition

Accumulation rates and sources of external nitrogen in decaying wood in a Norway spruce dominated forest

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

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