Plants sustain the terrestrial silicon cycle during ecosystem retrogression

The biogeochemical silicon cycle influences global primary productivity and carbon cycling, yet changes in silicon sources and cycling during long-term development of terrestrial ecosystems remain poorly understood. Here, we show that terrestrial silicon cycling shifts from pedological to biological control during long-term ecosystem development along 2-million-year soil chronosequences in Western Australia. Silicon availability is determined by pedogenic silicon in young soils and recycling of plant-derived silicon in old soils as pedogenic pools become depleted. Unlike concentrations of major nutrients, which decline markedly in strongly weathered soils, foliar silicon concentrations increase continuously as soils age. Our findings show that the retention of silicon by plants during ecosystem retrogression sustains its terrestrial cycling, suggesting important plant benefits associated with this element in nutrient-poor environments.

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Nitrogen and Phosphorus Limitation over Long-Term Ecosystem Development in Terrestrial Ecosystems

PLoS ONE ◽

10.1371/journal.pone.0042045 ◽

2012 ◽

Vol 7 (8) ◽

pp. e42045 ◽

Cited By ~ 72

Author(s):

Duncan N. L. Menge ◽

Lars O. Hedin ◽

Stephen W. Pacala

Keyword(s):

Terrestrial Ecosystems ◽

Phosphorus Limitation ◽

Ecosystem Development ◽

Nitrogen And Phosphorus

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Long-Term Spatiotemporal Variation of Net Primary Productivity and Its Correlation With the Urbanization: A Case Study in Hubei Province, China

Frontiers in Environmental Science ◽

10.3389/fenvs.2021.808401 ◽

2022 ◽

Vol 9 ◽

Author(s):

Ke Wu ◽

Chengfeng Zhou ◽

Yuxiang Zhang ◽

Ying Xu

Keyword(s):

Primary Productivity ◽

Urban Areas ◽

Net Primary Productivity ◽

Terrestrial Ecosystems ◽

Hubei Province ◽

Spatiotemporal Variation ◽

Anthropogenic Activity ◽

Rapid Urbanization

Net primary productivity (NPP) is a critical component in terrestrial ecosystem carbon cycles. Thus, quantitatively estimating and monitoring the dynamics of NPP have become key aspects for exploring the carbon cycle of terrestrial ecosystems. Anthropogenic activity, such as urbanization, has significant effects on NPP and increases pressure on the natural resources of a specific region. However, to date, although many studies have focused on the relationship between NPP variation and urbanization, they usually ignored any differences at a long-term spatiotemporal variation of urbanization factors, which led to the insufficient understanding of the urbanization-induced impacts on NPP. As a result, this study effectively explored the spatiotemporal variation of NPP from 2001 to 2012 and its corresponding relationship with urbanization, taking the Hubei Province in China as a case study area. To clarify the degree of urbanization, the spatial distribution and temporal variation of population and gross domestic product (GDP) were simulated based on the elevation-adjusted human settlement index and nighttime lights data. The major results showed that high NPP areas were located in those highlands with widespread woodland, in which the NPP value continued to grow during the period. The low NPP areas were mainly distributed in urban areas, and the NPP value had a continued and visible loss. The population and GDP both had a strong correlation with NPP. The significant negative correlation was concentrated in the center of Hubei, with a dense population and developed economy. In order to further realize their complex relationship, the correlation coefficients between the annual NPP and the two factors from 2001 to 2012 were calculated, and the changing trends were investigated. Overall, the findings of this study may provide a reference for studies on the interaction between ecological environment and socioeconomic processes under the background of global rapid urbanization.

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The Multiscale Monitoring of Peatland Ecosystem Carbon Cycling in the Middle Taiga Zone of Western Siberia: The Mukhrino Bog Case Study

Land ◽

10.3390/land10080824 ◽

2021 ◽

Vol 10 (8) ◽

pp. 824

Author(s):

Egor Dyukarev ◽

Evgeny Zarov ◽

Pavel Alekseychik ◽

Jelmer Nijp ◽

Nina Filippova ◽

...

Keyword(s):

Carbon Cycling ◽

Western Siberia ◽

Carbon Accumulation ◽

Middle Taiga ◽

Taiga Zone ◽

Field Station ◽

Moss Species ◽

Chamber Method ◽

The Impact

The peatlands of the West Siberian Lowlands, comprising the largest pristine peatland area of the world, have not previously been covered by continuous measurement and monitoring programs. The response of peatlands to climate change occurs over several decades. This paper summarizes the results of peatland carbon balance studies collected over ten years at the Mukhrino field station (Mukhrino FS, MFS) operating in the Middle Taiga Zone of Western Siberia. A multiscale approach was applied for the investigations of peatland carbon cycling. Carbon dioxide fluxes at the local scale studied using the chamber method showed net accumulation with rates from 110, to 57.8 gC m−2 at the Sphagnum hollow site. Net CO2 fluxes at the pine-dwarf shrubs-Sphagnum ridge varied from negative (−32.1 gC m−2 in 2019) to positive (13.4 gC m−2 in 2017). The cumulative May-August net ecosystem exchange (NEE) from eddy-covariance (EC) measurements at the ecosystem scale was −202 gC m−2 in 2015, due to the impact of photosynthesis of pine trees which was not registered by the chamber method. The net annual accumulation of carbon in the live part of mosses was estimated at 24–190 gC m−2 depending on the Sphagnum moss species. Long-term carbon accumulation rates obtained by radiocarbon analysis ranged from 28.5 to 57.2 gC m−2 yr−1, with local extremes of up to 176.2 gC m−2 yr−1. The obtained estimates of various carbon fluxes using EC and chamber methods, the accounting for Sphagnum growth and decomposition, and long-term peat accumulation provided information about the functioning of the peatland ecosystems at different spatial and temporal scales. Multiscale carbon flux monitoring reveals useful new information for forecasting the response of northern peatland carbon cycles to climatic changes.

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Rearing Trissolcus japonicus and Trissolcus mitsukurii for Biological Control of Halyomorpha halys

Insects ◽

10.3390/insects11110787 ◽

2020 ◽

Vol 11 (11) ◽

pp. 787

Author(s):

Giuseppino Sabbatini-Peverieri ◽

Christine Dieckhoff ◽

Lucrezia Giovannini ◽

Leonardo Marianelli ◽

Pio Federico Roversi ◽

...

Keyword(s):

Biological Control ◽

Control Method ◽

Egg Parasitoids ◽

Halyomorpha Halys ◽

Progeny Production ◽

Asian Origin ◽

Frequent Use ◽

Trissolcus Japonicus ◽

Cumulative Curves

Halyomorpha halys is a severe agricultural pest of Asian origin that has invaded many countries throughout the world. Pesticides are currently the favored control methods, but as a consequence of their frequent use, often disrupt Integrated Pest Management. Biological control with egg parasitoids is seen as the most promising control method over the long-term. Knowledge of the reproductive biology under laboratory conditions of the most effective candidates (Trissolcus japonicus and Trissolcus mitsukurii) for optimizing production for field releases is strongly needed. Rearing of these egg parasitoids was tested by offering three different host supply regimes using new emerged females and aged, host-deprived females in different combinations. Results showed a mean progeny per female ranging from 80 to 85 specimens for T. japonicus and from 63 to 83 for T. mitsukurii. Sex ratios were strongly female biased in all combinations and emergence rates exceeded 94% overall. Cumulative curves showed that longer parasitization periods beyond 10–14 days (under the adopted rearing regimes) will not lead to a significantly increase in progeny production. However, ageing females accumulate eggs in their ovaries that can be quickly laid if a sufficient number of host eggs are supplied, thus optimizing host resources. Our data showed that offering H. halys egg masses to host-deprived female Trissolcus once a week for three weeks allowed its eggs to accumulate in the ovary, providing the greatest number of offspring within a three week span.

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Biological Control and Mitigation of Aflatoxin Contamination in Commodities

Toxins ◽

10.3390/toxins13020104 ◽

2021 ◽

Vol 13 (2) ◽

pp. 104

Author(s):

Ferenc Peles ◽

Péter Sipos ◽

Szilvia Kovács ◽

Zoltán Győri ◽

István Pócsi ◽

...

Keyword(s):

Biological Control ◽

Secondary Metabolites ◽

Competitive Exclusion ◽

Aflatoxin Contamination ◽

Post Harvest ◽

Physical Chemical ◽

Synthetic Chemicals ◽

Ruminal Degradation

Aflatoxins (AFs) are toxic secondary metabolites produced mostly by Aspergillus species. AF contamination entering the feed and food chain has been a crucial long-term issue for veterinarians, medicals, agroindustry experts, and researchers working in this field. Although different (physical, chemical, and biological) technologies have been developed, tested, and employed to mitigate the detrimental effects of mycotoxins, including AFs, universal methods are still not available to reduce AF levels in feed and food in the last decades. Possible biological control by bacteria, yeasts, and fungi, their excretes, the role of the ruminal degradation, pre-harvest biocontrol by competitive exclusion or biofungicides, and post-harvest technologies and practices based on biological agents currently used to alleviate the toxic effects of AFs are collected in this review. Pre-harvest biocontrol technologies can give us the greatest opportunity to reduce AF production on the spot. Together with post-harvest applications of bacteria or fungal cultures, these technologies can help us strictly reduce AF contamination without synthetic chemicals.

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Multiple Evidence for Climate Patterns Influencing Ecosystem Productivity across Spatial Gradients in the Venice Lagoon

Journal of Marine Science and Engineering ◽

10.3390/jmse9040363 ◽

2021 ◽

Vol 9 (4) ◽

pp. 363

Author(s):

Camilla Bertolini ◽

Edouard Royer ◽

Roberto Pastres

Keyword(s):

Time Series ◽

Primary Productivity ◽

Clustering Analysis ◽

Venice Lagoon ◽

Spatial Effects ◽

Spatial Gradients ◽

Climate Forecasting ◽

Oxygen Production Rate ◽

Temporal And Spatial

Effects of climatic changes in transitional ecosystems are often not linear, with some areas likely experiencing faster or more intense responses, which something important to consider in the perspective of climate forecasting. In this study of the Venice lagoon, time series of the past decade were used, and primary productivity was estimated from hourly oxygen data using a published model. Temporal and spatial patterns of water temperature, salinity and productivity time series were identified by applying clustering analysis. Phytoplankton and nutrient data from long-term surveys were correlated to primary productivity model outputs. pmax, the maximum oxygen production rate in a given day, was found to positively correlate with plankton variables measured in surveys. Clustering analysis showed the occurrence of summer heatwaves in 2008, 2013, 2015 and 2018 and three warm prolonged summers (2012, 2017, 2019) coincided with lower summer pmax values. Spatial effects in terms of temperature were found with segregation between confined and open areas, although the patterns varied from year to year. Production and respiration differences showed that the lagoon, despite seasonality, was overall heterotrophic, with internal water bodies having greater values of heterotrophy. Warm, dry years with high salinity had lower degrees of summer autotrophy.

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Long-term dynamics of a predator used for biological control and decoupling from mosquito prey in a subtropical treehole ecosystem

Oecologia ◽

10.1007/s004420050225 ◽

1997 ◽

Vol 111 (2) ◽

pp. 189-200 ◽

Cited By ~ 22

Author(s):

L. P. Lounibos ◽

R. L. Escher ◽

N. Nishimura ◽

S. A. Juliano

Keyword(s):

Biological Control

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Contrasting research approaches to managing mistletoes in commercial forests and wooded pasturesThis minireview is one of a collection of papers based on a presentation from the Stem and Shoot Fungal Pathogens and Parasitic Plants: the Values of Biological Diversity session of the XXII International Union of Forestry Research Organization World Congress meeting held in Brisbane, Queensland, Australia, in 2005.

Botany ◽

10.1139/b08-109 ◽

2009 ◽

Vol 87 (1) ◽

pp. 1-9 ◽

Cited By ~ 7

Author(s):

Nick Reid ◽

Simon F. Shamoun

Keyword(s):

Biological Control ◽

Fungal Pathogens ◽

Biological Diversity ◽

Management Strategies ◽

Biodiversity Loss ◽

Classical Biological Control ◽

Dwarf Mistletoe ◽

Silvicultural Treatments ◽

Inundative Biological Control

Many mistletoe species are pests in agricultural and forest ecosystems throughout the world. Mistletoes are unusual “weeds” as they are generally endemic to areas where they achieve pest status and, therefore, classical biological control and broad-scale herbicidal control are usually impractical. In North American coniferous forests, dwarf mistletoe ( Arceuthobium spp.) infection results in major commercial losses and poses a public liability in recreation settings. Hyperparasitic fungi have potential as biological control agents of dwarf mistletoe, including species which attack shoots, berries, and the endophytic systems of dwarf mistletoe. Development of an inundative biological control strategy will be useful in situations where traditional silvicultural control is impractical or undesirable. In southern Australia, farm eucalypts are often attacked and killed by mistletoes ( Amyema spp.) in grazed landscapes where tree decline and biodiversity loss are major forms of land degradation. Although long-term strategies to achieve a balance between mistletoe and host abundance are promoted, many graziers want short-term options to treat severely infected trees. Recent research has revisited the efficiency and efficacy of silvicultural treatments and selective herbicides in appropriate situations. The results of recent research on these diverse management strategies in North America and Australia are summarized.

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