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1.
Sci Total Environ ; 806(Pt 1): 150514, 2022 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-34844300

RESUMEN

Grassland soils store a substantial proportion of the global soil carbon (C) stock. The transformation of C in grassland soils with respect to chemical composition and persistence strongly regulate the predicted terrestrial-atmosphere C flux in global C biogeochemical cycling models. In addition, increasing atmospheric nitrogen (N) deposition alters C chemistry in grassland soils. However, there remains controversy about the importance of mineralogical versus biochemical preservation of soil C, as well as uncertainty regarding how grassland soil C chemistry responds to elevated N. This study used grassland soils with diverse soil organic matter (SOM) chemistries in an 8-month aerobic incubation experiment to evaluate whether the chemical composition of SOM converged across sites over time, and how SOM persistence responded to the N addition. This study demonstrates that over the course of incubation, the richness of labile compounds decreased in soils with less ferrihydrite content, whereas labile compounds were more persistent in ferrihydrite rich soils. In contrast, we found that the richness of more complex compounds increased over the incubation in most sites, independent of soil mineralogy. Moreover, we demonstrate the extent to which the diverse chemical composition of SOM converged among sites in response to microbial decomposition. N fertilization decreased soil respiration and inhibited the convergence of molecular composition across ecosystems by altering N demand for microbial metabolism and chemical interactions between minerals and organic molecules. This study provides original evidence that the decomposition and metabolism of labile organic molecules were largely regulated by soil mineralogy (physicochemical preservation), while the metabolism of more complex organic molecules was controlled by substrate complexity (biochemical preservation) independent to mineral-organic interactions. This study advanced our understanding of the dynamic biogeochemical cycling of C by unveiling that N addition dampened C respiration and diminished the convergence of SOM chemistry across diverse grassland ecosystems.


Asunto(s)
Nitrógeno , Suelo , Carbono , Ecosistema , Pradera , Microbiología del Suelo
2.
Sci Total Environ ; 806(Pt 1): 150557, 2022 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-34582865

RESUMEN

Plant and soil elemental ratios of carbon (C), nitrogen (N) and phosphorus (P) play a central role in shaping the composition and structure of microbial communities. However, the relationships between plant and soil elemental C:N:P ratios and microbial diversity are still poorly understood. Here, we evaluated the effects of C:N:P ratios in plant-soil systems on microbial diversity in a chronosequence of restored grasslands (1, 5, 10, 15, 25, and 30 years since restoration) on the Loess Plateau. We found that C and N concentrations, C:N and C:P ratios in leaf, root, soil and microbial biomass, bacterial and fungal diversity (Shannon-Wiener index) gradually increased with year since grassland restoration. Microbial C:N:P ratios ranged from 17.8:4.5:1 to 24.3:6.6:1, and C:P ratio increased from 17.8:1 at the 1-year site to 24.3:1 at the 30-year site, indicating the increasing P limitation for soil microorganisms during grassland development. Soil microbial diversity increased with root, soil, and microbial C and N concentrations, and decreased with P concentration (p < 0.05). Structural equation modeling indicated that soil and microbial C:N and N:P ratios had the greatest influences on soil bacterial and fungal diversity, and elemental C:N:P ratios had a greater effect on soil fungal than bacterial diversity. Our findings emphasize the importance of elemental C:N:P ratios on soil microbial diversity, which is critical for formulating policies for sustainable biodiversity conservation in terrestrial ecosystems.


Asunto(s)
Microbiota , Suelo , Carbono/análisis , China , Pradera , Nitrógeno/análisis , Plantas , Microbiología del Suelo
3.
J Environ Manage ; 301: 113864, 2022 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-34600424

RESUMEN

The savannas of northern Australia are amongst the most fire-prone landscapes in the world. However, over the last fifteen years, increasing effort has been put into reducing fire extent and severity using prescribed burning strategies early in the dry season. This study seeks to improve the application of strategic fire management by providing a more detailed understanding of the landscape features that impede fire spread in Australia's tropical savannas using long-term satellite-derived fire histories. Spatial analysis of fire edges in Kakadu National Park based on fine-scale (30 m) Landsat imagery found that most fires stopped along linear edges, which were primarily associated with known features (roads, rivers and cliffs). Further analysis found linear features with the highest stopping ability covered only 13% of the park but divided the whole park into smaller containment regions. The stopping power of each feature type was found to vary according to their width and to change during the fire season, results that could help plan strategic fuel reduction burns. Similar results were seen with the lower-resolution continental-scale MODIS satellite-derived edge data. The MODIS dataset provided a means for applying fire edge analysis to support planning in areas of northern Australia that lack fine scale fire history mapping.


Asunto(s)
Incendios , Pradera , Australia , Ecosistema
4.
Sci Total Environ ; 805: 150342, 2022 Jan 20.
Artículo en Inglés | MEDLINE | ID: mdl-34818809

RESUMEN

It has been suggested that the sequestration of CO2 by agricultural soils offers a means to reduce atmospheric greenhouse gas (GHG) concentrations and in turn mitigate the impacts of climate change. Carbon sequestration by grassland soils, which account for more than 60% of agricultural land use in Ireland, could contribute to a successful net reduction of atmospheric GHG emissions in accordance with the COP21 Paris Agreement. However, current estimates of soil carbon sequestration are variable and it is likely that many permanent grasslands are close to saturation. A literature search shows that soil carbon sequestration is enhanced by a variety of different management strategies, although one option that has only been examined to date in New Zealand is full inversion tillage (FIT) during grassland renovation. FIT involves inverting topsoil, generally to depths of 30 cm, resulting in the movement of C-deficient subsoil to the surface and the burying of carbon-rich topsoil. In this review, we hypothesise that over the next ~30 years the new topsoil could incorporate large amounts of soil organic carbon (SOC) from the re-seeded sward vegetation and that the buried carbon will be retained. We assess the current capability of Irish grassland soils to sequester carbon and suggest a potential role of FIT during grassland renovation. An analysis of the distribution of grasslands in Ireland using the Land Parcel Identification System (LPIS) suggests that ~26% of Ireland's agricultural grasslands are suitable for FIT.


Asunto(s)
Secuestro de Carbono , Suelo , Agricultura , Carbono , Pradera
5.
Methods Mol Biol ; 2384: 139-152, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-34550573

RESUMEN

Social and prosocial behaviors, including communication, social bonding, and affiliation, parental behaviors, and empathy are key features of a highly social mammalian species. However, the neuronal mechanism in the brain underlying these behaviors remains unclear because of limited information on the social and prosocial behavioral levels in rodent models generally used in behavioral neuroscience studies.The rodent species, prairie vole (Microtus ochrogaster), is one of the nontraditional animal models with several advantages in experimental science over other rodent models, such as mice or rats. Additionally, it demonstrates characteristics advantageous in the study of social and prosocial behaviors, such as monogamous pair bonding behavior, biparental care, and consoling behavior toward partners stressed by aversive foot shock stimulus. Recent studies of prairie voles have highlighted the importance of oxytocin (OXT) and oxytocin receptor (OXTR)-mediated mechanisms in the regulation of these behaviors.Recently, we established assisted reproductive technologies for prairie voles, and successfully and efficiently generated an OXTR gene knockout (KO) prairie vole using Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/CRISPR-associated protein 9 (Cas9 ), a powerful genome editing tool with artificially developed single-strand guide RNAs (sgRNA) and Cas9 endonucleases.Herein, we describe the method for CRISPR /Cas9-mediated generation of OXTR KO prairie vole. This OXTR KO prairie vole can be a valuable tool to understand their unique social and prosocial behaviors and elucidate how the oxytocin system influences or modulates these behaviors in the brain.


Asunto(s)
Sistemas CRISPR-Cas , Animales , Arvicolinae/genética , Arvicolinae/metabolismo , Edición Génica , Pradera , Ratones , Oxitocina/genética , Ratas , Receptores de Oxitocina/genética , Técnicas Reproductivas Asistidas , Conducta Social
6.
Methods Mol Biol ; 2384: 257-269, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-34550580

RESUMEN

Ethological analyses of rodents are indispensable in current neuroscience research. Unlike traditional experimental rodents, prairie voles (Microtus ochrogaster) are monogamous, preferring to huddle with their sociosexual partner rather than stranger voles. Partner preference in prairie voles is assessed using three transparent chambers. The right and left chambers are connected with the central chamber via hollow tubes. An opposite-sex partner vole is tethered to the right or left chamber, while a stranger vole is tethered to the other one. A subject prairie vole is placed in the central chamber and allowed to roam freely in the three chambers for 3 h. Behaviors are recorded in a video recorder placed in front of the chambers. The duration to huddle with the partner and stranger voles is hand-scored in a blinded fashion. In this partner preference test, acrylic chambers and other materials are custom-made. Here, we describe detailed specification of these apparatuses. In addition, we mention protocols for cannula implantation and intracerebroventricular injection as well as a standard protocol of a passive avoidance test in prairie voles.


Asunto(s)
Arvicolinae , Pradera , Animales , Apareamiento , Conducta Social
7.
Sci Total Environ ; 803: 149948, 2022 Jan 10.
Artículo en Inglés | MEDLINE | ID: mdl-34482136

RESUMEN

The temperate steppe in northern China is important for sandstorm control and food/livestock production. Understanding the influence and regulatory control of cultivation on the water balance and water use efficiency (WUE) of this water-limited region would promote the sustainability of local ecosystem and food supply. This study combined eddy covariance system observational data and the Shuttleworth-Wallace model to investigate evapotranspiration (ET) and its composition in paired sites, including a free-grazing steppe site and an adjacent site reclaimed for spring wheat cultivation in Xilinhot, Inner Mongolia. Further, analysis of the WUE of both the ecosystem (WUEE) and the canopy (WUEC) under the two sites showed that the mean daily gross primary productivity (GPP) of the cultivation site was 3.84 gC·m-2·d-1, i.e., 15.7% higher than that of the free-grazing site (3.32 gC·m-2·d-1). Compared with the free-grazing site (1.76 kgH2O·m-2·d-1), the mean daily ET of the cultivation site (1.40 kgH2O·m-2·d-1) was reduced by 20.7%. The difference in ET was due mainly to suppression of evaporation at the cultivation site from increased shading associated with a higher leaf area index (LAI). The largely increased GPP of the cultivation site fundamentally contributed to the 54.7% higher WUEC (4.75 gC·kg-1H2O) in comparison with the free-grazing site (3.08 gC·kg-1H2O). The WUEE of the cultivation site was 57.9% higher than that of the free-grazing site. The variation of transpiration of the free-grazing site explained 64% of the change of WUEC. These results indicate that land use differences in the temperate steppe area changed vegetation productivity substantially. Moreover, ecosystem ET and its composition, as well as large-scale land use change, might influence the regional water use pattern and mass balance. Our findings help clarify the impact of typical land use change on regional WUE, and could promote development of visionary and effective strategies for the use of the limited resources in arid-semiarid regions.


Asunto(s)
Ecosistema , Triticum , China , Clima Desértico , Pradera , Estaciones del Año , Agua
8.
Sci Total Environ ; 803: 149700, 2022 Jan 10.
Artículo en Inglés | MEDLINE | ID: mdl-34487901

RESUMEN

The Eurasian steppe is the largest steppe region in the world and is an important part of the global grassland ecosystem. The eastern Eurasian steppe has favorable hydrothermal conditions and has the highest productivity and the richest biodiversity. Located in the arid and semi-arid region, the eastern Eurasian steppe has experienced large-scale grassland degradation due to dramatic climate change and intensive human activities during the past 20 years. Hence, accurate estimation of aboveground biomass (AGB, gC m-2) and belowground biomass (BGB, gC m-2) is necessary. In this study, plenty of AGB and BGB in-situ measurements were collected among dominated grassland types during summer in 2013 and 2016-2018 in the eastern Eurasian steppe. Vegetation indices from the Moderate Resolution Imaging Spectroradiometer (MODIS), Digital Elevation Model (DEM) and climate variables were chosen as independent variables to establish predictive models for AGB and BGB with random forest (RF). Both AGB (R2 = 0.47, MAE = 21.06 gC m-2, and RMSE = 27.52 gC m-2) and BGB (R2 = 0.44, MAE = 173.02 gC m-2, and RMSE = 244.20 gC m-2) models showed acceptable accuracy. Then the RF models were applied to generate spatially explicit AGB and BGB estimates for the study area over the last two decades (2000-2018). Both AGB and BGB showed higher values in the Greater Khingan Mountains and decreased gradually to the east and west sides. The mean values for AGB and BGB were 62.16 gC m-2 and 531.35 gC m-2, respectively. The climatic factors were much more important in controlling biomass than anthropogenic drivers, and shortage of water and raising temperature were the main limiting factor of AGB and BGB, respectively, in the peak growth season. These findings provide scientific data for the scientific management of animal husbandry and can contribute to the sustainable development of grassland ecology in the eastern Eurasian steppe.


Asunto(s)
Cambio Climático , Ecosistema , Biomasa , Pradera , Humanos , Imágenes Satelitales , Temperatura
9.
Sci Total Environ ; 803: 149950, 2022 Jan 10.
Artículo en Inglés | MEDLINE | ID: mdl-34487904

RESUMEN

Understanding relationships between biodiversity and ecosystem functions (BEF) and the way in which ecosystem functions respond to changing climatic conditions or community composition is useful for predicting ecological consequences of global changes. However, how soil moisture condition, plant species richness interactively affect ecosystem functions in shrub-encroached grasslands is poorly understood. We conducted a soil moisture × species richness microcosm experiment using semi-arid grassland species with a N-fixing shrub Caragana microphylla Lam. as the dominant species to evaluate how soil moisture and plant species richness affected ecosystem functions directly or indirectly via regulating community functional structure, such as community-weighted mean values (CWM) and functional dispersion (FDis). Soil moisture and species richness interactively affected soil functions (soil C-, N-, P cycles and soil multifunctionality), with greater species richness buffering the adverse effects of soil drought. Soil moisture and species richness showed opposite effects on FDis but similar effects on CWM. FDis mediated the indirect effect of soil moisture and species richness on ecosystem functions, while CWM only mediated the indirect effect of soil moisture. More specifically, both soil moisture and plant species richness were negatively associated with soil P cycle, and the CWMPC1 contributed by traits related to resource-conservative strategy was positively associated with soil N cycle. Species richness showed a positive direct effect on total shoot biomass, which was mainly contributed by the complementarity effect of neighbor species richness. This study provides strong empirical support of how biomass and soil nutrient cycles respond to the changes of soil moisture and plant species richness in C. microphylla shrub-encroached grasslands, and insights on the mechanisms underlying the interactive effects of soil condition and community species composition on multiple ecosystem functions in N-fixing shrub encroached grasslands in semi-arid grassland regions.


Asunto(s)
Ecosistema , Suelo , Biodiversidad , Biomasa , Clima Desértico , Pradera
10.
Sci Total Environ ; 804: 150112, 2022 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-34520909

RESUMEN

High-elevation grasslands worldwide provide essential hydrological services including water provision, flow regulation, and erosion control. Despite their importance, hydrological research of grasslands in montane regions is usually scarce and disperse, limiting the capacity to improve water resource management. We present a systematic literature review of the hydrological function of high Andean grasslands under conserved, degraded, and restored conditions in ecosystems situated above the tree line in the tropical Andes (páramos, punas, and jalcas). Most hydrological research on these grasslands has been developed in páramos (92%), especially in Ecuador, while research in punas is scarce (6%) despite being the largest grassland extent in the region. For páramos, published literature highlights the importance of conserving grasslands to facilitate water infiltration to soils, which in turn reduces erosive processes. Water-vegetation relations for conserved páramos are well understood, indicating that about 50% of water inputs return to the atmosphere via evapotranspiration, but knowledge about hydrological functions of conserved punas and jalcas is virtually non-existent. Under changing land use, afforestation of grassland ecosystems with exotic tree species, especially pines, reduces soil water storage as well as water yield and flow regulation capacity. Impacts of grazing and agriculture on the hydrological function of páramo grasslands strongly depend on historical land management and current land use practices and are not generalizable. Short-term restoration studies indicate that more than two years are necessary to recover the hydrological function of degraded grasslands, therefore medium and long-term studies are required to determine efficient restoration periods. These knowledge gaps limit the ability to extrapolate and regionalize findings. Future directions aimed to fill them are proposed, and methods successfully used to investigate the hydrology of high Andean grasslands are highlighted. This research not only enlightens what is known about the hydrology of high Andean grasslands, but also seeks to guide future hydrological evaluations to fill identified geographical and topical knowledge gaps precluding improved management of water resources in the tropical Andes.


Asunto(s)
Ecosistema , Hidrología , Agricultura , Pradera , Suelo
11.
Plant Biol (Stuttg) ; 24(1): 134-144, 2022 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-34618397

RESUMEN

Floral nectar is considered the most important floral reward for attracting pollinators. It contains large amounts of carbohydrates besides variable concentrations of amino acids and thus represents an important food source for many pollinators. Its nutrient content and composition can, however, strongly vary within and between plant species. The factors driving this variation in nectar quality are still largely unclear. We investigated factors underlying interspecific variation in macronutrient composition of floral nectar in 34 different grassland plant species. Specifically, we tested for correlations between the phylogenetic relatedness and morphology of plants and the carbohydrate (C) and total amino acid (AA) composition and C:AA ratios of nectar. We found that compositions of carbohydrates and (essential) amino acids as well as C:AA ratios in nectar varied significantly within and between plant species. They showed no clear phylogenetic signal. Moreover, variation in carbohydrate composition was related to family-specific structural characteristics and combinations of morphological traits. Plants with nectar-exposing flowers, bowl- or parabolic-shaped flowers, as often found in the Apiaceae and Asteraceae, had nectar with higher proportions of hexoses, indicating a selective pressure to decelerate evaporation by increasing nectar osmolality. Our study suggests that variation in nectar nutrient composition is, among others, affected by family-specific combinations of morphological traits. However, even within species, variation in nectar quality is high. As nectar quality can strongly affect visitation patterns of pollinators and thus pollination success, this intra- and interspecific variation requires more studies to fully elucidate the underlying causes and the consequences for pollinator behaviour.


Asunto(s)
Pradera , Néctar de las Plantas , Flores , Filogenia , Polinización
12.
J Environ Manage ; 302(Pt A): 113938, 2022 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-34688049

RESUMEN

It is generally accepted that land use and land management practices impact climate change through sequestration of carbon in soils, but modulation of surface energy budget can also be important. Using Landsat data to characterize cropland albedos in Canada's three prairie soil zones, this study estimates the atmospheric carbon equivalent drawdown of albedo radiative forcing for three management practices: 1) moving from conventional tillage to no-till, 2) eliminating summer fallow in crop rotations, and 3) growing crops with higher albedos. In a 50-year time horizon, conversion from conventional tillage to no-till results in a total equivalent atmospheric CO2 (CO2-eq) drawdown of 1.0-1.5 kg m-2, and conversion from summer fallow to crops results in CO2-eq drawdown of 1.1-2.4 kg m-2. Conversion of summer fallow to crops results in different magnitudes of CO2-eq drawdown depending on specific crops. Lentils, peas, and canola have relatively higher albedo than that of spring wheat and flax; hence, a larger magnitude of CO2-eq drawdown results when they replace summer fallow in the rotation. For the management changes from 1990 to 2019 for the whole Canadian Prairies, albedo changes induced a CO2-eq drawdown of about 179.3 ± 20.9 Tg due to increased area of no-till, and 101.6 ± 9.5 Tg due to reduced area under fallow. The study shows that the magnitudes of CO2-eq drawdown due to albedo change are comparable to that due to soil carbon sequestration. Therefore, it is important to account for cropland albedo changes in assessing the potential of agricultural management practices to mitigate climate change.


Asunto(s)
Carbono , Pradera , Agricultura , Canadá , Carbono/análisis , Cambio Climático , Suelo
13.
Ecol Lett ; 25(1): 52-64, 2022 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-34708508

RESUMEN

Climate change is disproportionately impacting mountain ecosystems, leading to large reductions in winter snow cover, earlier spring snowmelt and widespread shrub expansion into alpine grasslands. Yet, the combined effects of shrub expansion and changing snow conditions on abiotic and biotic soil properties remains poorly understood. We used complementary field experiments to show that reduced snow cover and earlier snowmelt have effects on soil microbial communities and functioning that persist into summer. However, ericaceous shrub expansion modulates a number of these impacts and has stronger belowground effects than changing snow conditions. Ericaceous shrub expansion did not alter snow depth or snowmelt timing but did increase the abundance of ericoid mycorrhizal fungi and oligotrophic bacteria, which was linked to decreased soil respiration and nitrogen availability. Our findings suggest that changing winter snow conditions have cross-seasonal impacts on soil properties, but shifts in vegetation can modulate belowground effects of future alpine climate change.


Asunto(s)
Ecosistema , Nieve , Cambio Climático , Pradera , Estaciones del Año , Suelo
14.
Sci Total Environ ; 806(Pt 3): 151224, 2022 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-34728201

RESUMEN

Precipitation is a primary climatic determinant of grassland productivity, with many global change experiments manipulating precipitation. Here we examine the impacts of precipitation addition and reduction treatment intensity and duration on grassland above- (ANPP) and below- (BNPP) ground net primary productivity in a large-scale meta-analysis. We tested, 1) the double asymmetry model of sensitivity, specifically whether the sensitivity of productivity decreases with treatment intensity under increased precipitation and increases with treatment intensity under decreased precipitation, 2) whether the sensitivity of productivity to precipitation change decreases with treatment length, and 3) how the sensitivity of productivity changes with climate conditions. ANPP showed higher sensitivity than BNPP under increased precipitation but similar sensitivity to BNPP under decreased precipitation. The sensitivity of ANPP and BNPP decreased with increasing treatment intensity (e.g., percentage change in precipitation, ΔPPT) and leveled off in the long-term. With increased precipitation, the sensitivity of productivity decreased with increasing treatment length (e.g., experimental duration) and leveled off in the long-term, whereas the sensitivity increased with increasing treatment length under reduced precipitation. Furthermore, the sensitivity of productivity to precipitation change decreased with increasing mean annual precipitation and temperature. Finally, our meta-analysis shows that above- and belowground net primary productivity have asymmetric responses to precipitation change. Together these results highlight the complex mechanisms underlying the impacts of precipitation change, particularly the intensity and duration of such changes, on grassland productivity.


Asunto(s)
Cambio Climático , Pradera , Ecosistema
15.
Glob Chang Biol ; 28(1): 128-139, 2022 01.
Artículo en Inglés | MEDLINE | ID: mdl-34587352

RESUMEN

The carbon stored in soil exceeds that of plant biomass and atmospheric carbon and its stability can impact global climate. Growth of decomposer microorganisms mediates both the accrual and loss of soil carbon. Growth is sensitive to temperature and given the vast biological diversity of soil microorganisms, the response of decomposer growth rates to warming may be strongly idiosyncratic, varying among taxa, making ecosystem predictions difficult. Here, we show that 15 years of warming by transplanting plant-soil mesocosms down in elevation, strongly reduced the growth rates of soil microorganisms, measured in the field using undisturbed soil. The magnitude of the response to warming varied among microbial taxa. However, the direction of the response-reduced growth-was universal and warming explained twofold more variation than did the sum of taxonomic identity and its interaction with warming. For this ecosystem, most of the growth responses to warming could be explained without taxon-specific information, suggesting that in some cases microbial responses measured in aggregate may be adequate for climate modeling. Long-term experimental warming also reduced soil carbon content, likely a consequence of a warming-induced increase in decomposition, as warming-induced changes in plant productivity were negligible. The loss of soil carbon and decreased microbial biomass with warming may explain the reduced growth of the microbial community, more than the direct effects of temperature on growth. These findings show that direct and indirect effects of long-term warming can reduce growth rates of soil microbes, which may have important feedbacks to global warming.


Asunto(s)
Microbiota , Suelo , Carbono , Cambio Climático , Ecosistema , Pradera , Microbiología del Suelo
16.
Biol Psychiatry ; 91(1): 141-151, 2022 01 01.
Artículo en Inglés | MEDLINE | ID: mdl-33549315

RESUMEN

BACKGROUND: The ability to form enduring social bonds is characteristic of human nature, and impairments in social affiliation are central features of severe neuropsychiatric disorders including autism spectrum disorder and schizophrenia. Owing to its ability to form long-term pair-bonds, the socially monogamous prairie vole has emerged as an excellent model to study the neurobiology of social attachment. Despite the enduring nature of the bond, however, surprisingly few genes have been implicated in the pair-bonding process in either sex. METHODS: Male and female prairie voles (Microtus ochrogaster) were cohabitated with an opposite-sex partner for 24 hours or 3 weeks, and transcriptomic regulations in the nucleus accumbens were measured by RNA sequencing. RESULTS: We found sex-specific response patterns despite similar behavioral indicators of pair-bond establishment. Indeed, 24 hours of cohabitation with an opposite-sex partner induced widespread transcriptomic changes that remained sustained to some extent in females after 3 weeks but returned to baseline before a second set of regulations in males. This led to a highly sexually biased nucleus accumbens transcriptome at 3 weeks related to processes such as neurotransmission, protein turnover, and DNA transcription. In particular, we found sex-specific alterations of mitochondrial dynamics following cohabitation, with a shift toward fission in males. CONCLUSIONS: In addition to identifying the genes, networks, and pathways involved in the pair-bonding process in the nucleus accumbens, our work illustrates the vast extent of sex differences in the molecular mechanisms underlying pair-bonding in prairie voles and paves the way to further our understanding of the complex social bonding process.


Asunto(s)
Trastorno del Espectro Autista , Transcriptoma , Animales , Arvicolinae , Femenino , Pradera , Humanos , Masculino , Apareamiento , Conducta Sexual Animal , Conducta Social
17.
Sci Total Environ ; 804: 150032, 2022 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-34798716

RESUMEN

Mountainous alpine ecosystems are sensitive to global change, where soil nutrient content would potentially vary under current climate change background, and thus possibly influence the activity of nitrifiers and denitrifiers, as well as N2O emissions. However, within mountainous alpine ecosystems, the potential variation of soil nutrients under current global change and the consequence to N2O emission from nitrification and denitrification are still unclarified, hampering a comprehensive understanding of the feedback mechanisms between the nitrogen cycle and climate change. In order to fill this knowledge gap, we selected alpine grasslands at three different elevations and investigated the distribution and environmental drivers of nitrifiers and denitrifiers. The results showed that the lowest elevation site tended to have higher total phosphorus (TP) accumulation within the topsoil. The abundance of functional groups, emission of CO2 and N2O, and the N2O/CO2 ratio showed a decreasing trend along elevation. TP was the greatest influence on denitrifier composition (nosZ/narG and nirS/nirK ratios) and considerably influenced nitrifier composition (AOA/AOB ratio), and was significantly correlated to the N2O/CO2 ratio. In microcosms of soils from the highest elevation site, TP addition decreased the ratios of nosZ/narG, nirS/nirK, and AOA/AOB, and increased N2O/CO2 ratio and N2O emission, thus contributing to positive climate change feedback. This study indicates the potential for change within the nitrifier and denitrifier communities under current climate change, and highlights the role TP plays in governing nitrification and denitrification in mountainous alpine ecosystems.


Asunto(s)
Fósforo , Suelo , Cambio Climático , Desnitrificación , Ecosistema , Retroalimentación , Pradera , Óxido Nitroso/análisis , Microbiología del Suelo
18.
Sci Total Environ ; 806(Pt 3): 151324, 2022 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-34749967

RESUMEN

Due to the influence of climate change and extensive grazing, a large proportion of steppe grassland has been degraded worldwide. The Chinese government initiated a series of grassland restoration programs to reverse the degradation. However, the limiting factors and the restoration potential remain unknown. Here we present a process-based model to assess the restoration gap (RG) defined as maximum biomass differences between non-degraded and degraded grasslands with different degrees of soil and vegetation degradation. The process-based model Agricultural Production Systems Simulator (APSIM) was evaluated utilizing observation data from both typical and meadow steppes under natural conditions in terms of phenology, dynamics of above-ground biomass and soil water content. Scenario analysis and sensitivity analysis were subsequently performed to address the RG and controlling factors during 1969-2018. The results showed that the calibrated model performed well with r > 0.75 and model efficiency factor EF > 0.5 for all the simulation components. According to our model results, the RG was larger in typical steppe compared to that of meadow steppe and it increased with increasing soil and/or vegetation degradation, to ~60% under extremely degraded scenarios. Both soil and vegetation degradation led to reduced water use efficiency, with an elevated proportion of soil evaporation to evapotranspiration (Es/ET), however, the limiting factor for RG varied. The degradation of soil water holding capacity contributed more to RG regardless of climate conditions for typical steppe in all years and for meadow steppe in dry years. In wet years the importance of vegetation coverage reduction increased for RG in meadow steppe, where the relative importance of vegetation coverage (valued at 62.8%) was 25.6% higher than that of soil degradation. Our results demonstrated the importance of considering climate variations when developing protection and restoration programs for grassland ecosystems.


Asunto(s)
Ecosistema , Pradera , Biomasa , China , Cambio Climático , Suelo
19.
J Environ Manage ; 302(Pt B): 114073, 2022 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-34763189

RESUMEN

Existing methods for spatial quantification of grassland utilization intensity cannot meet the demand for accurate detection of the spatial distribution of grassland utilization intensity in the Qinghai-Tibetan Plateau with high spatial resolution. In this paper, a method based on remote-sensing observations and simulations of grassland growth dynamics is proposed. The grassland enhanced vegetation index (EVI) time-series curve during the growing season characterizes the growth of grassland in the corresponding pixel; The deviation between the observed and potential EVI curves indicates the disturbance on grassland growth imposed by human activities, and it can characterize the grassland utilization intensity during the growing season. Based on the main idea described above, absolute and relative disturbances are calculated and used as quantitative indicators of grassland utilization intensity defined from different perspectives. Livestock amount at the pixel scale is obtained by pixel-by-pixel calculations based on the function relationship at the township scale between absolute disturbance and livestock density, which is specific quantitative indicator that considers the mode of grassland utilization. In simulating the potential EVI of grassland, the lag and accumulation effects of meteorological factors are investigated at the daily scale using a multi-objective genetic algorithm. Further, the nonlinear functions between multiple environmental factors (e.g., grassland type, topography, soil, meteorology) and the grassland EVI are established using an error back-propagation feedforward artificial neural network (ANN-BP) with parameter optimization. Finally, the potential EVIs of all grassland pixels are simulated on the basis of this model. The method is applied to the Selinco basin on the Qinghai-Tibetan Plateau and validated by examining the spatial consistency of the results with township-scale livestock density and grazing pressure. The final results indicate that the proposed method can accurately detect the spatial distribution of grassland utilization intensity which is appliable in the similar regions.


Asunto(s)
Ecosistema , Pradera , Actividades Humanas , Humanos , Suelo , Tibet
20.
Sci Total Environ ; 810: 152227, 2022 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-34896142

RESUMEN

While the organic carbon stored in soil is a sizeable proportion of the total carbon stored in terrestrial ecosystems, it is also a considerable source of greenhouse gas emissions. In this study, we examined how the carbon pool had changed in an area of temperate grassland in Inner Mongolia, China, over a period of 14 years. A field experiment was set up in 2003 and was treated with 6 nitrogen (N) treatments:0, 2, 4, 8, 16, and 32 g·N·m-2·yr-1 as dry urea (CO(NH2)2). We collected soil samples in 2017, and divided them into three size aggregates: silt-clay fraction, microaggregate, and small macroaggregate. We determined various soil extracellular enzyme activities of these three categories, namely ß-glucosidase (BG), N-acetyl-ß-D-glucosaminidase (NAG), acid phosphatase (AP), peroxidase (PER), and phenol oxidase (POX). We found that the soil enzyme activities increased under N additions. In addition, the BG activity was higher, but the PER activity was lower, in the small macroaggregates than the silt-clay fraction. Furthermore, we found that the soil extracellular enzyme activities and soil physico-chemical properties in the small macroaggregates were not correlated. Rather, we found that some of the soil extracellular enzyme activities were negatively correlated with the pH value, microbial biomass carbon (MBC), total organic carbon (TOC), and positively correlated with the inorganic nitrogen content (IN), in the microaggregates and the silt-clay fraction. A key discovery was that the N additions had no effect on the 0-10 cm soil layer (fractions <2000 um) organic carbon pool or the distribution of different-sized aggregates, probably because they were regulated through the changes of plant, soil, and microbial interactions. The results will contribute to improve our understanding of how N additions affect TOC and different aggregate size classes in soil, and will support better predictions of how N deposition might contribute to future climate change.


Asunto(s)
Carbono , Suelo , Carbono/análisis , China , Ecosistema , Pradera , Nitrógeno/análisis , Microbiología del Suelo
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