scholarly journals Are vegetation–soil systems drivers of ecosystem carbon contents along an elevational gradient in a highland temperate forest?

2019 ◽  
Vol 49 (3) ◽  
pp. 296-304 ◽  
Author(s):  
Isela Jasso-Flores ◽  
Leopoldo Galicia ◽  
Felipe García-Oliva ◽  
Angelina Martínez-Yrízar

Vegetation–soil systems differentially influence the ecosystem processes related to the carbon cycle, particularly when one tree species is dominant over wide geographic regions that are undergoing climate change. The objective of this study was to quantify the stocks of ecosystem carbon in three vegetation–soil systems along a highland elevational gradient in central Mexico. The vegetation–soil systems, from lower to higher elevation, were dominated by Alnus jorullensis Kunth, Abies religiosa (Kunth) Schltdl. & Cham., and Pinus hartwegii Lindl., respectively. Above- and below-ground tree biomass was determined in each system, along with the litter, coarse woody material, roots, and litterfall. The A. religiosa system had the greatest stock of aboveground biomass carbon (216 ± 31 Mg C·ha−1). The A. jorullensis system had the greatest production of litterfall (3.1 ± 0.08 Mg·ha−1·year−1); however, the carbon content of this litter layer (1.2 ± 0.32 Mg C·ha−1) was lower than that of P. hartwegii (10.1 ± 0.28 Mg C·ha−1). Thus, the litter layer in the A. jorullensis system had markedly the shortest residence time (8 years), suggesting high rates of litter decomposition. The soil carbon stock (at soil depth of 1 m) was greater in A. jorullensis (189 Mg C·ha−1) and P. hartwegii (137 Mg C·ha−1) than in A. religiosa (68 Mg C·ha−1). The A. religiosa and A. jorullensis systems had the highest and lowest total ecosystem C content (301 and 228 Mg C·ha−1, respectively). Upward migration of the A. religiosa system in response to global climate change, however, could cause losses by 2030 of 187 Mg C·ha−1 associated with aboveground biomass.

2021 ◽  
Author(s):  
Cyrill Zosso ◽  
Nicholas O.E. Ofiti ◽  
Jennifer L. Soong ◽  
Emily F. Solly ◽  
Margaret S. Torn ◽  
...  

<p>Soils will warm in near synchrony with the air over the whole profiles following global climate change. It is largely unknown how subsoil (below 30 cm) microbial communities will respond to this warming and how plant-derived soil organic carbon (SOC) will be affected. Predictions how climate change will affect the large subsoil carbon pool (>50 % of SOC is below 30 cm soil depth) remain uncertain.</p><p>At Blodgett forest (California, USA) a field warming experiment was set up in 2013 warming whole soil profiles to 100 cm soil depth by +4°C compared to control plots. We took samples in 2018, after 4.5 years of continuous warming and investigated how warming has affected the abundance and community structure of microoganisms (using phospholipid fatty acids, PLFAs), and plant litter (using cutin and suberin).</p><p>The warmed subsoil (below 30 cm) contained significantly less microbial biomass (28%) compared to control plots, whereas the topsoil remained unchanged. Additionally below 50 cm, the microbial community was different in warmed as compared to control plots. Actinobacteria were relatively more abundant and Gram+ bacteria adapted their cell-membrane structure to warming. The decrease in microbial abundance might be related to lower SOC concentrations in warmed compared to control subsoils. In contrast to smaller SOC concentrations and less fine root mass in the warmed plots, the concentrations of the plant polymers suberin and cutin did not change. Overall our results demonstrate that already four seasons of simulated whole-soil warming caused distinct depth-specific responses of soil biogeochemistry: warming altered the subsoil microbial community, but not concentrations of plant-derived soil organic carbon.</p>


Forests ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 816
Author(s):  
Jéssica Merecí-Guamán ◽  
Fernando Casanoves ◽  
Diego Delgado-Rodríguez ◽  
Pablo Ochoa ◽  
Miguel Cifuentes-Jara

Mangrove forests play an important role in mitigating climate change but are threatened by aquaculture expansion. The inclusion of mangroves in climate change mitigation strategies requires measuring of carbon stocks and the emissions caused by land use change over time. This study provides a synthesis of carbon stocks in mangrove and shrimp ponds in the Gulf of Guayaquil. In this study area, we identified 134,064 ha of mangrove forest and 153,950 ha of shrimp farms. Two mangrove strata were identified according to their height and basal area: medium-statured mangrove (lower height and basal area) and tall mangrove (greater height and basal area). These strata showed statistical differences in aboveground carbon stocks. In both strata, the most abundant mangrove species was Rhizophora mangle. For both strata, trees had a maximum height (>30 m), and their density was greater than 827 ha−1. Total ecosystem level carbon stocks (measured to 1 m soil depth) were 320.9 Mg C ha−1 in medium-statured mangroves and 419.4 Mg C ha−1 in tall mangroves. The differences are attributable to higher basal area, soil organic carbon concentrations and salinity, tidal range, origin of allochthonous material, and herbivory patterns. Mangrove soils represented >80% of the total ecosystem carbon. Ecosystem carbon stocks were lower (81.9 Mg C ha−1) in the shrimp farms, 50% less than in undisturbed mangroves. Our results highlight mangroves as tropical ecosystems with extremely high carbon storage; therefore, they play an important role in mitigating climate change. This research provides a better understanding of how carbon stocks in this gulf are found and can be used for design strategies to protect global natural carbon sinks.


2020 ◽  
Vol 2020 ◽  
pp. 1-5
Author(s):  
Lilu Kumari Magar ◽  
Gandhiv Kafle ◽  
Pradeep Aryal

This paper reports the findings of a research study conducted in three tropical agroforestry systems in the Makawanpur district of Nepal, to quantify the spatial and vertical distribution of soil organic carbon in 30 cm soil profile depth in agrisilviculture, home garden, and silvopasture. The three agroforestry systems represent tropical agroforests of Nepal. It was found that the soil had 24.91 t/ha soil organic carbon in 30 cm soil profile in 2018, with 2.1% soil organic matter concentration in average. Bulk density was found increasing with an increase in soil depth. The soil organic carbon was not found significantly different across different agroforestry systems. Looking into the values of stocks of soil organic carbon, it is concluded that the tropical agroforests have played a role in global climate change mitigation by storing considerable amounts of soil organic carbon and the storage capacity can further be increased. Involvement of farmers in the management of tropical agroforests cannot be ignored in the process of climate change mitigation.


2019 ◽  
Vol 11 (23) ◽  
pp. 6760
Author(s):  
Zhang ◽  
Zhang ◽  
Li

As global climate change deeply affects terrestrial ecosystem carbon cycle, it is necessary to understand how grasslands respond to climate change. In this study, we examined the role of climate change on net primary productivity (NPP) from 1961 to 2010 in the Hulunbuir grasslands of China, using a calibrated process-based biogeochemistry model. The results indicated that: Temperature experienced a rise trend from 1961; summer and autumn precipitation showed a rise trend before the 1990s and decline trend after the 1990s. Winter and spring precipitation showed an ascending trend. Simulated NPP had a high inter-annual variability during the study period, ranging from 139 g Cm−2 to 348 g Cm−2. The annual mean NPP was significant and positive in correlation with the annual variation of precipitation, and the trend was first raised then fell with the turn point at the 1990s. Temperature had a 20–30 d lag in summer, but none in spring and autumn; precipitation had a 10–20 d lag in summer. The climate lag effect analysis confirmed that temperature had a positive effect on NPP in spring and a negative effect in summer.


2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Martina Alrutz ◽  
Jorge Antonio Gómez Díaz ◽  
Ulf Schneidewind ◽  
Thorsten Krömer ◽  
Holger Kreft

Background: Tropical montane forests are important reservoirs of carbon and biodiversity but are threatened by deforestation and climate change. It is important to understand how forest structure and aboveground biomass change along gradients of elevation and succession. Questions: What are the interactive effect of elevation and two stages of succession on forest structure parameters? Studied species: Tree communities. Study site and dates: Cofre de Perote, Veracruz, Mexico. August to December 2015. Methods: We studied four sites along an elevational gradient (500, 1,500, 2,500, and 3,500 m). At each elevation and each forest type, we established five 20 × 20 m plots (n = 40 plots). Within each plot, we measured stem density, mean diameter at breast height (dbh), and tree height and derived basal area and aboveground biomass (AGB). Results: AGB peaked at 2,500 m and was significantly related to elevation and succession, with higher values in old-growth forests than in secondary forests at higher altitudes. Lower values of mean dbh and basal area were found at higher elevations. At the lowest elevation, both successional stages had the same values of stem density and AGB. At both lower elevations, secondary forests had higher values of dbh and basal area. There were high biomass stocks in the old-growth forest at 2,500 and 3,500 m. Conclusions: Old-growth forests at higher elevations are threatened by deforestation, consequently these remaining fragments must be preserved because of their storage capacity for biomass and their ability to mitigate climate change.


Author(s):  
Monica L. Noon ◽  
Allie Goldstein ◽  
Juan Carlos Ledezma ◽  
Patrick R. Roehrdanz ◽  
Susan C. Cook-Patton ◽  
...  

AbstractAvoiding catastrophic climate change requires rapid decarbonization and improved ecosystem stewardship at a planetary scale. The carbon released through the burning of fossil fuels would take millennia to regenerate on Earth. Though the timeframe of carbon recovery for ecosystems such as peatlands, mangroves and old-growth forests is shorter (centuries), this timeframe still exceeds the time we have remaining to avoid the worst impacts of global warming. There are some natural places that we cannot afford to lose due to their irreplaceable carbon reserves. Here we map ‘irrecoverable carbon’ globally to identify ecosystem carbon that remains within human purview to manage and, if lost, could not be recovered by mid-century, by when we need to reach net-zero emissions to avoid the worst climate impacts. Since 2010, agriculture, logging and wildfire have caused emissions of at least 4.0 Gt of irrecoverable carbon. The world’s remaining 139.1 ± 443.6 Gt of irrecoverable carbon faces risks from land-use conversion and climate change. These risks can be reduced through proactive protection and adaptive management. Currently, 23.0% of irrecoverable carbon is within protected areas and 33.6% is managed by Indigenous peoples and local communities. Half of Earth’s irrecoverable carbon is concentrated on just 3.3% of its land, highlighting opportunities for targeted efforts to increase global climate security.


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