Pub Date : 2023-12-06DOI: 10.1186/s13717-023-00472-7
Daigard R. Ortega Rodriguez, Raúl Sánchez-Salguero, Andrea Hevia, Renata C. Bovi, Marciel J. Ferreira, James H. Speer, Fidel A. Roig, Mario Tomazello-Filho
The increase in the frequency and intensity of droughts is pointed out as one of the main factors altering biogeochemical cycles in the Amazon basin. An eco-nutritional approach using X-ray fluorescence micro-analysis (µXRF) is proposed to verify the long- and short-term effects of droughts on the growth and xylem nutrient concentrations of Cedrela fissilis Vell. Fourteen radii were selected from a tree-ring width chronology and X-rayed by Itrax Multiscanner. Profiles of ring width, wood density, and concentrations of aluminum (Al), phosphorus (P), sulfur (S), calcium (Ca), potassium (K), manganese (Mn), iron (Fe) and strontium (Sr) together with Al/Ca, Ca/Mn, K/Ca, Sr/Ca and Mn/S ratios were constructed and correlated with precipitation, temperature, the difference between precipitation and potential evapotranspiration (P-PET) and standardized precipitation–evapotranspiration index (SPEI). During dry years, C. fissilis showed narrower, less dense rings, lower Al, P, S and Ca, and higher K and Fe concentrations (the opposite was found in wet years). Ring width decreased (together with Al, P, S, K, Ca, Mn, Fe, Sr, Al/Ca, K/Ca and Sr/Ca) and wood density increased (together with Ca/Mn and Mn/S), which was associated with an increase in evapotranspiration and temperature over time, mainly since 1990. Cedrela fissilis showed a tendency to increase its capacity for resistance, and a recovery and resilience in growth over time associated with responses in Al, Ca, P and S. However, it showed a risk in the capacity for recovery of the pre-drought density values, associated with unsatisfactory responses in Al, Ca, K, Fe and P. This study is the first attempt to analyze tree-ring nutritional evidences of C. fissilis trees to climate sensitivity and resilience to drought, based on long-term data from seasonal moist tropical forests of the Amazon. Our data suggested that C. fissilis is undergoing alterations in the concentration, use and redistribution of nutrients associated with increasing wood density and decreasing growth over time, due to the increase of drought frequency in the southern Amazon.
{"title":"Does climate change alter the nutrient trends of Cedrela fissilis Vell. trees in the southern Brazilian Amazon?","authors":"Daigard R. Ortega Rodriguez, Raúl Sánchez-Salguero, Andrea Hevia, Renata C. Bovi, Marciel J. Ferreira, James H. Speer, Fidel A. Roig, Mario Tomazello-Filho","doi":"10.1186/s13717-023-00472-7","DOIUrl":"https://doi.org/10.1186/s13717-023-00472-7","url":null,"abstract":"The increase in the frequency and intensity of droughts is pointed out as one of the main factors altering biogeochemical cycles in the Amazon basin. An eco-nutritional approach using X-ray fluorescence micro-analysis (µXRF) is proposed to verify the long- and short-term effects of droughts on the growth and xylem nutrient concentrations of Cedrela fissilis Vell. Fourteen radii were selected from a tree-ring width chronology and X-rayed by Itrax Multiscanner. Profiles of ring width, wood density, and concentrations of aluminum (Al), phosphorus (P), sulfur (S), calcium (Ca), potassium (K), manganese (Mn), iron (Fe) and strontium (Sr) together with Al/Ca, Ca/Mn, K/Ca, Sr/Ca and Mn/S ratios were constructed and correlated with precipitation, temperature, the difference between precipitation and potential evapotranspiration (P-PET) and standardized precipitation–evapotranspiration index (SPEI). During dry years, C. fissilis showed narrower, less dense rings, lower Al, P, S and Ca, and higher K and Fe concentrations (the opposite was found in wet years). Ring width decreased (together with Al, P, S, K, Ca, Mn, Fe, Sr, Al/Ca, K/Ca and Sr/Ca) and wood density increased (together with Ca/Mn and Mn/S), which was associated with an increase in evapotranspiration and temperature over time, mainly since 1990. Cedrela fissilis showed a tendency to increase its capacity for resistance, and a recovery and resilience in growth over time associated with responses in Al, Ca, P and S. However, it showed a risk in the capacity for recovery of the pre-drought density values, associated with unsatisfactory responses in Al, Ca, K, Fe and P. This study is the first attempt to analyze tree-ring nutritional evidences of C. fissilis trees to climate sensitivity and resilience to drought, based on long-term data from seasonal moist tropical forests of the Amazon. Our data suggested that C. fissilis is undergoing alterations in the concentration, use and redistribution of nutrients associated with increasing wood density and decreasing growth over time, due to the increase of drought frequency in the southern Amazon.","PeriodicalId":11419,"journal":{"name":"Ecological Processes","volume":"8 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2023-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138538119","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-01DOI: 10.1186/s13717-023-00466-5
Wangchen Sonam, Yongqin Liu, Liangdong Guo
Microbial communities in different plant compartments are relatively independent entities. However, the influence of environmental factors on the microbial community in different compartments of periglacial plants remains unclear. In this study, we quantified the bacterial communities in the rhizosphere soil, as well as root and leaf endosphere compartments of a periglacial plant, Potentilla fruticosa var. albicans, using high-throughput DNA sequencing. Moreover, we evaluated the impacts of habitat types (glacier terminus zone, moraine ridge, and alpine meadow) on the bacterial community in different plant compartments of Potentilla fruticosa var. albicans. Our results showed that habitat type had a significant effect on the alpha diversity (Chao1 richness) of endophytic bacteria, but not on the rhizospheric bacteria. The community composition of rhizospheric and endophytic bacteria was significantly different across the three habitats, and habitat type had a greater effect on the endophytic bacteria than on rhizospheric bacteria. The contribution of rhizosphere soil to the root and leaf endophytes decreased with the transformation of habitats from glacier terminus zone to alpine meadow. In contrast, host selection pressure sequentially increased from the glacier terminus zone to the moraine ridge to the alpine meadow. Furthermore, we found that the bacterial co-occurrence network in the alpine meadow was more modular but had lower complexity and connectedness than that in the glacier terminus zone. The bacterial community was governed primarily by stochastic processes regardless of habitat type. This study reveals that the diversity and composition of endophytic bacteria associated with Potentilla fruticosa var. albicans are more affected by habitat types than that of rhizospheric bacteria. Our study also demonstrates that the assembly patterns and co-occurrence patterns of bacterial communities associated with Potentilla fruticosa var. albicans vary by habitat type. These results advance the current understanding of community assembly and ecological interactions of microbial communities associated with periglacial plants.
不同植物室的微生物群落是相对独立的实体。然而，环境因子对冰缘植物不同区室微生物群落的影响尚不清楚。在这项研究中，我们使用高通量DNA测序技术定量了冰缘植物白白Potentilla fruticosa var. albicans根际土壤中的细菌群落，以及根和叶的内圈区室。此外，我们还评估了不同生境类型(冰川终端区、冰碛垄和高寒草甸)对白白蕨不同植物室细菌群落的影响。结果表明，生境类型对内生细菌的α多样性(Chao1丰富度)有显著影响，但对根际细菌没有显著影响。不同生境根际细菌和内生细菌的群落组成差异显著，生境类型对根际细菌的影响大于对根际细菌的影响。根际土壤对根和叶内生菌的贡献随着生境由冰川终端区向高寒草甸的转变而减小。从冰川终端区到冰碛垄再到高寒草甸，寄主选择压力依次增大。与冰川终端区相比，高寒草甸的细菌共生网络更模块化，但复杂性和连通性较低。与生境类型无关，细菌群落主要受随机过程控制。本研究表明，与白白翻陵草相关的内生细菌多样性和组成受生境类型的影响大于根际细菌的影响。我们的研究还表明，与白僵菌相关的细菌群落的聚集模式和共生模式因生境类型而异。这些结果促进了目前对冰缘植物微生物群落组成和生态相互作用的认识。
{"title":"Endophytic bacteria in the periglacial plant Potentilla fruticosa var. albicans are influenced by habitat type","authors":"Wangchen Sonam, Yongqin Liu, Liangdong Guo","doi":"10.1186/s13717-023-00466-5","DOIUrl":"https://doi.org/10.1186/s13717-023-00466-5","url":null,"abstract":"Microbial communities in different plant compartments are relatively independent entities. However, the influence of environmental factors on the microbial community in different compartments of periglacial plants remains unclear. In this study, we quantified the bacterial communities in the rhizosphere soil, as well as root and leaf endosphere compartments of a periglacial plant, Potentilla fruticosa var. albicans, using high-throughput DNA sequencing. Moreover, we evaluated the impacts of habitat types (glacier terminus zone, moraine ridge, and alpine meadow) on the bacterial community in different plant compartments of Potentilla fruticosa var. albicans. Our results showed that habitat type had a significant effect on the alpha diversity (Chao1 richness) of endophytic bacteria, but not on the rhizospheric bacteria. The community composition of rhizospheric and endophytic bacteria was significantly different across the three habitats, and habitat type had a greater effect on the endophytic bacteria than on rhizospheric bacteria. The contribution of rhizosphere soil to the root and leaf endophytes decreased with the transformation of habitats from glacier terminus zone to alpine meadow. In contrast, host selection pressure sequentially increased from the glacier terminus zone to the moraine ridge to the alpine meadow. Furthermore, we found that the bacterial co-occurrence network in the alpine meadow was more modular but had lower complexity and connectedness than that in the glacier terminus zone. The bacterial community was governed primarily by stochastic processes regardless of habitat type. This study reveals that the diversity and composition of endophytic bacteria associated with Potentilla fruticosa var. albicans are more affected by habitat types than that of rhizospheric bacteria. Our study also demonstrates that the assembly patterns and co-occurrence patterns of bacterial communities associated with Potentilla fruticosa var. albicans vary by habitat type. These results advance the current understanding of community assembly and ecological interactions of microbial communities associated with periglacial plants.","PeriodicalId":11419,"journal":{"name":"Ecological Processes","volume":"76 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138538099","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-30DOI: 10.1186/s13717-023-00470-9
Xinyu Wei, Fuzhong Wu, Koenraad Van Meerbeek, Ellen Desie, Xiangyin Ni, Kai Yue, Petr Heděnec, Jing Yang, Nannan An
Changes in soil greenhouse gas (GHG) fluxes caused by nitrogen (N) addition are considered as the key factors contributing to global climate change (global warming and altered precipitation regimes), which in turn alters the feedback between N addition and soil GHG fluxes. However, the effects of N addition on soil GHG emissions under climate change are highly variable and context-dependent, so that further syntheses are required. Here, a meta-analysis of the interactive effects of N addition and climate change (warming and altered precipitation) on the fluxes of three main soil GHGs [carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O)] was conducted by synthesizing 2103 observations retrieved from 57 peer-reviewed articles on multiple terrestrial ecosystems globally. The interactive effects of N addition and climate change on GHG fluxes were generally additive. The combination of N addition and warming or altered precipitation increased N2O emissions significantly while it had minimal effects on CO2 emissions and CH4 uptake, and the effects on CH4 emissions could not be evaluated. Moreover, the magnitude of the combined effects did not differ significantly from the effects of N addition alone. Apparently, the combined effects on CO2 and CH4 varied among ecosystem types due to differences in soil moisture, which was in contrast to the soil N2O emission responses. The soil GHG flux responses to combined N addition and climate change also varied among different climatic conditions and experimental methods. Overall, our findings indicate that the effects of N addition and climate change on soil GHG fluxes were relatively independent, i.e. combined effects of N addition and climate change were equal to or not significantly different from the sum of their respective individual effects. The effects of N addition on soil GHG fluxes influence the feedbacks between climate change and soil GHG fluxes.
{"title":"Warming and altered precipitation rarely alter N addition effects on soil greenhouse gas fluxes: a meta-analysis","authors":"Xinyu Wei, Fuzhong Wu, Koenraad Van Meerbeek, Ellen Desie, Xiangyin Ni, Kai Yue, Petr Heděnec, Jing Yang, Nannan An","doi":"10.1186/s13717-023-00470-9","DOIUrl":"https://doi.org/10.1186/s13717-023-00470-9","url":null,"abstract":"Changes in soil greenhouse gas (GHG) fluxes caused by nitrogen (N) addition are considered as the key factors contributing to global climate change (global warming and altered precipitation regimes), which in turn alters the feedback between N addition and soil GHG fluxes. However, the effects of N addition on soil GHG emissions under climate change are highly variable and context-dependent, so that further syntheses are required. Here, a meta-analysis of the interactive effects of N addition and climate change (warming and altered precipitation) on the fluxes of three main soil GHGs [carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O)] was conducted by synthesizing 2103 observations retrieved from 57 peer-reviewed articles on multiple terrestrial ecosystems globally. The interactive effects of N addition and climate change on GHG fluxes were generally additive. The combination of N addition and warming or altered precipitation increased N2O emissions significantly while it had minimal effects on CO2 emissions and CH4 uptake, and the effects on CH4 emissions could not be evaluated. Moreover, the magnitude of the combined effects did not differ significantly from the effects of N addition alone. Apparently, the combined effects on CO2 and CH4 varied among ecosystem types due to differences in soil moisture, which was in contrast to the soil N2O emission responses. The soil GHG flux responses to combined N addition and climate change also varied among different climatic conditions and experimental methods. Overall, our findings indicate that the effects of N addition and climate change on soil GHG fluxes were relatively independent, i.e. combined effects of N addition and climate change were equal to or not significantly different from the sum of their respective individual effects. The effects of N addition on soil GHG fluxes influence the feedbacks between climate change and soil GHG fluxes.","PeriodicalId":11419,"journal":{"name":"Ecological Processes","volume":"21 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2023-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138538120","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-28DOI: 10.1186/s13717-023-00467-4
Yan Li, Xi Qi, Jianpan Xin, Chu Zhao, Runan Tian
Eutrophication and acid rain are two threats that many water bodies must contend with. Eutrophication and climate change have accelerated widespread outbreaks of cyanobacterial blooms as both have become more severe. Pontederia cordata, a garden ornamental plant, can inhibit some algae growth and remove total nitrogen (TN) and total phosphorus (TP) from the water. In this study, we investigated how simulated acid rain and eutrophication co-pollution affected P. cordata's growth physiology and ability to inhibit algae growth. Under mild eutrophication (2 mg·L−1 TN, 0.4 mg·L−1 TP, and 15 mg·L−1 CODMn) or weak acid rain (pH = 5.0), P. cordata alleviated the degree of cell membrane lipid peroxidation by stabilizing superoxide dismutase (SOD) and catalase (CAT) activities in the leaves, allowing for normal plant growth. Under mild eutrophication and acid rain conditions, cultured P. cordata water samples maintained strong algae inhibition by reducing the Chl a content and SOD activity of Microcystis aeruginosa cells. Compound stress where acid rain was the primary inhibitory factor along with moderate or severe eutrophication inhibited P. cordata growth, which probably reduced the input of algae-inhibiting allelochemicals, thus reducing its ability to inhibit algae. In summary, P. cordata has application potential in mild eutrophic water and acid rain (pH ≥ 4). These findings provide guidance for further research on phytoremediation and algae control in scenarios of compound pollution.
{"title":"Physiological responses and algae inhibition of Pontederia cordata to simulated eutrophication and acid rain co-pollution","authors":"Yan Li, Xi Qi, Jianpan Xin, Chu Zhao, Runan Tian","doi":"10.1186/s13717-023-00467-4","DOIUrl":"https://doi.org/10.1186/s13717-023-00467-4","url":null,"abstract":"Eutrophication and acid rain are two threats that many water bodies must contend with. Eutrophication and climate change have accelerated widespread outbreaks of cyanobacterial blooms as both have become more severe. Pontederia cordata, a garden ornamental plant, can inhibit some algae growth and remove total nitrogen (TN) and total phosphorus (TP) from the water. In this study, we investigated how simulated acid rain and eutrophication co-pollution affected P. cordata's growth physiology and ability to inhibit algae growth. Under mild eutrophication (2 mg·L−1 TN, 0.4 mg·L−1 TP, and 15 mg·L−1 CODMn) or weak acid rain (pH = 5.0), P. cordata alleviated the degree of cell membrane lipid peroxidation by stabilizing superoxide dismutase (SOD) and catalase (CAT) activities in the leaves, allowing for normal plant growth. Under mild eutrophication and acid rain conditions, cultured P. cordata water samples maintained strong algae inhibition by reducing the Chl a content and SOD activity of Microcystis aeruginosa cells. Compound stress where acid rain was the primary inhibitory factor along with moderate or severe eutrophication inhibited P. cordata growth, which probably reduced the input of algae-inhibiting allelochemicals, thus reducing its ability to inhibit algae. In summary, P. cordata has application potential in mild eutrophic water and acid rain (pH ≥ 4). These findings provide guidance for further research on phytoremediation and algae control in scenarios of compound pollution.","PeriodicalId":11419,"journal":{"name":"Ecological Processes","volume":"16 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2023-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138538117","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-17DOI: 10.1186/s13717-023-00468-3
Haftay Hailu Gebremedhn, Ousmane Ndiaye, Sylvanus Mensah, Cofélas Fassinou, Simon Taugourdeau, Torbern Tagesson, Paulo Salgado
The savannah ecosystems of Sahel have experienced continuous and heavy grazing of livestock for centuries but still, their vegetation response to grazing pressure remains poorly understood. In this study, we analysed the herbaceous plant dynamics, measured by species diversity, composition, cover, and biomass in response to grazing pressure in the savannah ecosystems of Sahel. In Senegal, we selected four savannah sites represented with high, moderate, light and no grazing intensity levels. Transect survey methods were used for sampling the vegetation data within each of the sites. Species richness and composition were analysed using species accumulation curve and multivariate analyses. Furthermore, we used General Linear Models and a piecewise Structural Equation Model (pSEM) to examine the relationships between grazing intensity, vegetation cover, diversity and biomass. The herbaceous species diversity and composition varied significantly among the different grazing intensity levels (p <0.001). The plant species composition shifted from the dominance of grass cover to the dominance of forb cover with increasing grazing pressure. Moreover, the attributes of species diversity, herbaceous biomass, and ground cover were higher on sites with low grazing than sites with high and moderate grazing intensity. Across all sites, species diversity was positively related to total biomass. The pSEM explained 37% of the variance in total biomass and revealed that grazing intensity negatively influenced total biomass both directly and indirectly through its negative influence on species diversity. Managing grazing intensity may lead to higher plant production and higher mixed forage establishment in the dryland savannah ecosystems. This information can be used to support land management strategies and promote sustainable grazing practices that balance the needs of livestock with the conservation of ecosystem health and biodiversity.
几个世纪以来，萨赫勒草原生态系统经历了持续和大量的牲畜放牧，但其植被对放牧压力的反应仍然知之甚少。在本研究中，我们分析了萨赫勒草原生态系统中草本植物对放牧压力的响应，包括物种多样性、组成、覆盖和生物量。在塞内加尔，我们选择了四个草原遗址，分别代表高、中等、轻度和无放牧强度水平。采用样带调查方法对每个站点内的植被数据进行采样。利用物种积累曲线和多变量分析对物种丰富度和组成进行了分析。利用一般线性模型(General Linear Models)和分段结构方程模型(piecwise Structural Equation Model, pSEM)分析了放牧强度、植被覆盖度、多样性和生物量之间的关系。不同放牧强度下草本物种多样性和组成差异显著(p <0.001)。随着放牧压力的增加，植物种类组成由草被为主向草被为主转变。低放牧区的物种多样性、草本生物量和地被盖度均高于高放牧区和中等放牧区。所有样地的物种多样性均与总生物量呈正相关。该模型解释了总生物量变化的37%，揭示了放牧强度通过对物种多样性的负向影响直接和间接地对总生物量产生负向影响。管理放牧强度可以提高旱地草原生态系统的植物产量和混合饲料的建立。这些信息可用于支持土地管理战略和促进可持续放牧做法，以平衡牲畜的需求与保护生态系统健康和生物多样性。
{"title":"Grazing effects on vegetation dynamics in the savannah ecosystems of the Sahel","authors":"Haftay Hailu Gebremedhn, Ousmane Ndiaye, Sylvanus Mensah, Cofélas Fassinou, Simon Taugourdeau, Torbern Tagesson, Paulo Salgado","doi":"10.1186/s13717-023-00468-3","DOIUrl":"https://doi.org/10.1186/s13717-023-00468-3","url":null,"abstract":"The savannah ecosystems of Sahel have experienced continuous and heavy grazing of livestock for centuries but still, their vegetation response to grazing pressure remains poorly understood. In this study, we analysed the herbaceous plant dynamics, measured by species diversity, composition, cover, and biomass in response to grazing pressure in the savannah ecosystems of Sahel. In Senegal, we selected four savannah sites represented with high, moderate, light and no grazing intensity levels. Transect survey methods were used for sampling the vegetation data within each of the sites. Species richness and composition were analysed using species accumulation curve and multivariate analyses. Furthermore, we used General Linear Models and a piecewise Structural Equation Model (pSEM) to examine the relationships between grazing intensity, vegetation cover, diversity and biomass. The herbaceous species diversity and composition varied significantly among the different grazing intensity levels (p <0.001). The plant species composition shifted from the dominance of grass cover to the dominance of forb cover with increasing grazing pressure. Moreover, the attributes of species diversity, herbaceous biomass, and ground cover were higher on sites with low grazing than sites with high and moderate grazing intensity. Across all sites, species diversity was positively related to total biomass. The pSEM explained 37% of the variance in total biomass and revealed that grazing intensity negatively influenced total biomass both directly and indirectly through its negative influence on species diversity. Managing grazing intensity may lead to higher plant production and higher mixed forage establishment in the dryland savannah ecosystems. This information can be used to support land management strategies and promote sustainable grazing practices that balance the needs of livestock with the conservation of ecosystem health and biodiversity.","PeriodicalId":11419,"journal":{"name":"Ecological Processes","volume":"293 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2023-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138538106","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Background In the Indo-Gangetic Plain, rice–wheat is the most extensively practiced crop rotation. The escalating issue of crop residue burning, particularly rice straw, and the necessity to lower the exorbitant expenses associated with fertilizer inputs stand out as significant challenges for farmers in the region. A well-suited integrated nutrient management (INM) strategy that focuses on recycling crop residues can serve as a solution to address these issues. Such a strategy not only mitigates air pollution resulting from residue burning but also helps combat water pollution due to nitrate losses from agroecosystems. Field experiments were used to evaluate the suitability of eight INM-modules that included various combinations of inorganic fertilizer rates (50%, 100%, 150% of recommended dose), crop residues (wheat and rice stubble retention at 30 cm standing stubble equivalent to 1/3 the straw yield), rice straw compost (RSC), farmyard manure (FYM), and green manuring (GM), compared to 100% recommended dose of fertilizers (F) and no fertilizer application. Results There was a considerable improvement in nitrogen mineralization, grain yields, and nitrogen use efficiency under GM + RSC-F50 and GM + FYM-F50. These INM modules would permit a 50% reduction in the use of chemical fertilizers. There was a little yield penalty with in situ rice residue incorporation at 100% F; however, this could be overcome with 150% F fertilizer application. In situ retention of wheat straw with a full application of fertilizer resulted in steadily rising crop yields over time. Changes in the redox potential, soil pH, and soil organic carbon best accounted for the observed trajectories in nitrogen use efficiency. Conclusion The most promising INM modules for adoption by farmers in the Indo-Gangetic Plain to judiciously use crop residues and curtail chemical fertilizer inputs are green manuring with Sesbania aculeata + rice straw compost at 5 t ha −1 + only 50% of recommended dose of fertilizers (GM + RSC-F50), and green manuring with Sesbania aculeata + farmyard manure at 5 t ha −1 + only 50% of recommended dose of fertilizers (GM + FYM-F50). Sole incorporation of crop residues without nitrogen augmentation from other sources might not help curtail chemical fertilizer use. Composting rice straw, which otherwise is widely burnt, proved a useful nitrogen source and a vital component of INM. Waste rice straw composting at the community scale and its application as a nutrient source can help achieve sustainable nitrogen management in the agroecosystems of Indo-Gangetic Plain.
背景在印度恒河平原，水稻-小麦是最广泛实行的作物轮作。农作物秸秆焚烧问题日益严重，尤其是秸秆焚烧问题，以及降低化肥投入相关费用的必要性，都是该地区农民面临的重大挑战。一个非常适合的综合营养管理(INM)战略，侧重于作物残留物的循环利用，可以作为解决这些问题的解决方案。这一战略不仅减轻了燃烧残渣造成的空气污染，而且还有助于防治农业生态系统中硝酸盐损失造成的水污染。通过田间试验，对8个inm模块的适宜性进行了评价，这些模块包括不同组合的无机肥料用量(推荐用量的50%、100%和150%)、作物残茬(小麦和水稻留茬30 cm相当于秸秆产量的1/3)、秸秆堆肥(RSC)、农家粪肥(FYM)和绿色施肥(GM)，与100%推荐用量的肥料(F)和不施肥相比。结果GM + RSC-F50和GM + fys - f50处理在氮素矿化、产量和氮素利用效率方面均有显著提高。这些INM模块将使化学肥料的使用减少50%。在100% F条件下，稻渣就地掺入对产量影响不大;然而，这可以通过150%的F肥施用来克服。随着时间的推移，小麦秸秆的原位保留和充分施用化肥导致作物产量稳步上升。氧化还原电位、土壤pH和土壤有机碳的变化最能解释氮利用效率的变化轨迹。结论印度河-恒河平原农民为合理利用作物秸秆和减少化肥投入而采用的最有希望的INM模式是田菁+水稻秸秆堆肥5 t / h - 1 +仅为化肥推荐用量的50% (GM + RSC-F50)和田菁+农家肥5 t / h - 1 +仅为化肥推荐用量的50% (GM + fsm - f50)的绿色施肥。在没有从其他来源补充氮肥的情况下，单独掺入作物秸秆可能无助于减少化肥的使用。秸秆堆肥被证明是一种有用的氮源，也是INM的重要组成部分。群落尺度的废稻草堆肥及其作为营养源的应用有助于印度恒河平原农业生态系统实现可持续的氮素管理。
{"title":"Residue recycling options and their implications for sustainable nitrogen management in rice–wheat agroecosystems","authors":"Ajay Kumar Bhardwaj, Kapil Malik, Manu Rani, Uttam Kumar Mandal, Nirmalendu Basak, Awtar Singh, Rajender Kumar Yadav, Suresh Kumar Chaudhari, Dinesh Kumar Sharma","doi":"10.1186/s13717-023-00464-7","DOIUrl":"https://doi.org/10.1186/s13717-023-00464-7","url":null,"abstract":"Abstract Background In the Indo-Gangetic Plain, rice–wheat is the most extensively practiced crop rotation. The escalating issue of crop residue burning, particularly rice straw, and the necessity to lower the exorbitant expenses associated with fertilizer inputs stand out as significant challenges for farmers in the region. A well-suited integrated nutrient management (INM) strategy that focuses on recycling crop residues can serve as a solution to address these issues. Such a strategy not only mitigates air pollution resulting from residue burning but also helps combat water pollution due to nitrate losses from agroecosystems. Field experiments were used to evaluate the suitability of eight INM-modules that included various combinations of inorganic fertilizer rates (50%, 100%, 150% of recommended dose), crop residues (wheat and rice stubble retention at 30 cm standing stubble equivalent to 1/3 the straw yield), rice straw compost (RSC), farmyard manure (FYM), and green manuring (GM), compared to 100% recommended dose of fertilizers (F) and no fertilizer application. Results There was a considerable improvement in nitrogen mineralization, grain yields, and nitrogen use efficiency under GM + RSC-F50 and GM + FYM-F50. These INM modules would permit a 50% reduction in the use of chemical fertilizers. There was a little yield penalty with in situ rice residue incorporation at 100% F; however, this could be overcome with 150% F fertilizer application. In situ retention of wheat straw with a full application of fertilizer resulted in steadily rising crop yields over time. Changes in the redox potential, soil pH, and soil organic carbon best accounted for the observed trajectories in nitrogen use efficiency. Conclusion The most promising INM modules for adoption by farmers in the Indo-Gangetic Plain to judiciously use crop residues and curtail chemical fertilizer inputs are green manuring with Sesbania aculeata + rice straw compost at 5 t ha −1 + only 50% of recommended dose of fertilizers (GM + RSC-F50), and green manuring with Sesbania aculeata + farmyard manure at 5 t ha −1 + only 50% of recommended dose of fertilizers (GM + FYM-F50). Sole incorporation of crop residues without nitrogen augmentation from other sources might not help curtail chemical fertilizer use. Composting rice straw, which otherwise is widely burnt, proved a useful nitrogen source and a vital component of INM. Waste rice straw composting at the community scale and its application as a nutrient source can help achieve sustainable nitrogen management in the agroecosystems of Indo-Gangetic Plain.","PeriodicalId":11419,"journal":{"name":"Ecological Processes","volume":"106 24","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135137685","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-06DOI: 10.1186/s13717-023-00463-8
Isabel Cantera, Céline Jézéquel, Tony Dejean, Jérôme Murienne, Régis Vigouroux, Alice Valentini, Sébastien Brosse
Abstract Background Deforestation is a widespread disturbance for neotropical freshwater ecosystems. While biodiversity declines have been associated with deforestation, its functional consequences for stream and river fish faunas remain poorly understood. In this study, we explored how deforestation affects the different facets of the functional structure of fish communities inventoried using environmental DNA metabarcoding in 64 river and 35 stream sites of French Guiana. Specifically, we investigated how functional richness, divergence, evenness and identity of fish faunas are affected by deforestation. Results We showed that anthropogenic disturbances in French Guiana are modifying the functional diversity of freshwater fish communities. These disturbances not only affected the amount of functional traits held by the communities but also the identity of the traits and the internal structure of the functional space. Consequently, different facets of the functional diversity supported by fish assemblages were altered. In streams, deforestation did not affect the overall diversity of traits but reduced functional redundancy, underlined by a shift in functional identity towards assemblages dominated by pelagic detritivores. In contrast, river fish faunas experienced a decline in functional richness, paired with shifts in functional identity and a loss of fish species with extreme functions. Conclusions The response to deforestation differed between streams and rivers, but it supports the hypothesis that deforestation is linked to functional changes in fish assemblages. By diminishing the range of the functions in rivers or by jeopardizing the redundancy of functions in streams, deforestation could severely hamper the functioning and stability of neotropical freshwater ecosystems.
{"title":"Functional responses to deforestation in fish communities inhabiting neotropical streams and rivers","authors":"Isabel Cantera, Céline Jézéquel, Tony Dejean, Jérôme Murienne, Régis Vigouroux, Alice Valentini, Sébastien Brosse","doi":"10.1186/s13717-023-00463-8","DOIUrl":"https://doi.org/10.1186/s13717-023-00463-8","url":null,"abstract":"Abstract Background Deforestation is a widespread disturbance for neotropical freshwater ecosystems. While biodiversity declines have been associated with deforestation, its functional consequences for stream and river fish faunas remain poorly understood. In this study, we explored how deforestation affects the different facets of the functional structure of fish communities inventoried using environmental DNA metabarcoding in 64 river and 35 stream sites of French Guiana. Specifically, we investigated how functional richness, divergence, evenness and identity of fish faunas are affected by deforestation. Results We showed that anthropogenic disturbances in French Guiana are modifying the functional diversity of freshwater fish communities. These disturbances not only affected the amount of functional traits held by the communities but also the identity of the traits and the internal structure of the functional space. Consequently, different facets of the functional diversity supported by fish assemblages were altered. In streams, deforestation did not affect the overall diversity of traits but reduced functional redundancy, underlined by a shift in functional identity towards assemblages dominated by pelagic detritivores. In contrast, river fish faunas experienced a decline in functional richness, paired with shifts in functional identity and a loss of fish species with extreme functions. Conclusions The response to deforestation differed between streams and rivers, but it supports the hypothesis that deforestation is linked to functional changes in fish assemblages. By diminishing the range of the functions in rivers or by jeopardizing the redundancy of functions in streams, deforestation could severely hamper the functioning and stability of neotropical freshwater ecosystems.","PeriodicalId":11419,"journal":{"name":"Ecological Processes","volume":"2022 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135634816","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-30DOI: 10.1186/s13717-023-00465-6
Fei Liu, Zixin Wang, Zhijun Xia, Jianwei Wang, Huanzhang Liu
Abstract Background To rehabilitate the depleted fish resources of the Yangtze River Basin, China, a 10-year fishing ban has been implemented. This national initiative has attracted worldwide attention. The present study aimed to explore the ecological process and recovery effectiveness of this complete fishing ban in the Chishui River, the first river where the fishing ban was enacted in the Yangtze River Basin. Changes in fish resources were analyzed based on investigations conducted 5 years before (2012–2016) and 5 years after (2017–2021) the implementation of the fishing ban in four reaches along the longitudinal gradient. Results A total of 140 fish species, including 127 native and 13 exotic species, were collected during the study period. The number of fish species as well as the diversity indices showed no significant temporal changes. However, 11 native species that had disappeared for many years appeared again after the fishing ban. The occurrence rates of some key protected species, Procypris rabaudi , Acipenser dabryanus , Euchiloglanis davidi and Myxocyprinus asiaticus , increased after the fishing ban, while Coreius guichenoti , Percocypris pingi , Onychostoma angustistomata and Leptobotia rubrilabris showed no obvious recovery. The fish assemblage structure in nearly all reaches (except the headwater) showed significant temporal changes with an increase in the relative abundance of larger body-sized species. The population structure of most dominant species improved greatly with the mean standard length and the mean body weight as well as the proportion of larger-sized individuals clearly increasing. In addition, the density of fishes changed dramatically with the catch per unit effort (CPUE) increasing by 140–210% for different study reaches. Conclusions The present study confirmed that the complete fishing closure is an effective measure to facilitate fish resources recovery. These results provide valuable references for evaluating the effectiveness of the 10-year fishing ban policy in the entire Yangtze River.
{"title":"Changes in fish resources 5 years after implementation of the 10-year fishing ban in the Chishui River, the first river with a complete fishing ban in the Yangtze River Basin","authors":"Fei Liu, Zixin Wang, Zhijun Xia, Jianwei Wang, Huanzhang Liu","doi":"10.1186/s13717-023-00465-6","DOIUrl":"https://doi.org/10.1186/s13717-023-00465-6","url":null,"abstract":"Abstract Background To rehabilitate the depleted fish resources of the Yangtze River Basin, China, a 10-year fishing ban has been implemented. This national initiative has attracted worldwide attention. The present study aimed to explore the ecological process and recovery effectiveness of this complete fishing ban in the Chishui River, the first river where the fishing ban was enacted in the Yangtze River Basin. Changes in fish resources were analyzed based on investigations conducted 5 years before (2012–2016) and 5 years after (2017–2021) the implementation of the fishing ban in four reaches along the longitudinal gradient. Results A total of 140 fish species, including 127 native and 13 exotic species, were collected during the study period. The number of fish species as well as the diversity indices showed no significant temporal changes. However, 11 native species that had disappeared for many years appeared again after the fishing ban. The occurrence rates of some key protected species, Procypris rabaudi , Acipenser dabryanus , Euchiloglanis davidi and Myxocyprinus asiaticus , increased after the fishing ban, while Coreius guichenoti , Percocypris pingi , Onychostoma angustistomata and Leptobotia rubrilabris showed no obvious recovery. The fish assemblage structure in nearly all reaches (except the headwater) showed significant temporal changes with an increase in the relative abundance of larger body-sized species. The population structure of most dominant species improved greatly with the mean standard length and the mean body weight as well as the proportion of larger-sized individuals clearly increasing. In addition, the density of fishes changed dramatically with the catch per unit effort (CPUE) increasing by 140–210% for different study reaches. Conclusions The present study confirmed that the complete fishing closure is an effective measure to facilitate fish resources recovery. These results provide valuable references for evaluating the effectiveness of the 10-year fishing ban policy in the entire Yangtze River.","PeriodicalId":11419,"journal":{"name":"Ecological Processes","volume":"308 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136102500","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-09DOI: 10.1186/s13717-023-00462-9
Bruno Walter Pietzsch, Aaron Schmidt, Jürgen Groeneveld, Dominik Bahlburg, Bettina Meyer, Uta Berger
Abstract Background Krill ( Euphausia superba ) and salps ( Salpa thompsoni ) are key macrozooplankton grazers in the Southern Ocean ecosystem. However, due to differing habitat requirements, both species previously exhibited little spatial overlap. With ongoing climate change-induced seawater temperature increase and regional sea ice loss, salps can now extend their spatial distribution into historically krill-dominated areas and increase rapidly due to asexual reproduction when environmental conditions are favorable. Understanding the potential effects on krill is crucial, since krill is a species of exceptional trophic significance in the Southern Ocean food web. Negative impacts on krill could trigger cascading effects on its predators and prey. To address this question, we combined two individual-based models on salps and krill, which describe the whole life cycle of salp individuals and the dynamic energy budget of individual krill. The resulting new model PEKRIS ( PErformance of KRIll vs. Salps ) simulates a krill population for 100 years under varying chlorophyll-a concentrations in the presence or absence of salps. Results All of the investigated krill population properties (abundance, mean length, and yearly egg production) were significantly impacted by the presence of salps. On the other hand, salp density was not impacted if krill were present. The medians of krill population properties deviated during variable maximum chlorophyll-a density per year when salps were introduced by − 99.9% (− 234 individuals per 1000 m 3 ) for krill density, − 100% (− 22,062 eggs per 1000 m 3 ) for krill eggs and − 0.9% (− 0.3 mm) for mean length of krill. Conclusions If both species compete for the same food resource in a closed space, salps seem to inhibit krill populations. Further simulation studies should investigate whether this effect prevails if different phytoplankton sizes and consumption preferences of krill are implemented. Furthermore, direct predation of the two species or consumption of krill fecal pellets by salps could change the impact size of the food competition.
摘要背景磷虾(Euphausia superba)和海鞘(Salpa thompsoni)是南大洋生态系统中重要的大型浮游动物。然而，由于不同的栖息地需求，这两个物种以前表现出很少的空间重叠。随着气候变化引起的海水温度升高和区域海冰的减少，海鞘现在可以将其空间分布扩展到历史上磷虾为主的地区，并在环境条件有利的情况下通过无性繁殖迅速增加。了解对磷虾的潜在影响至关重要，因为磷虾是南大洋食物网中具有特殊营养意义的物种。对磷虾的负面影响可能会引发对其捕食者和猎物的连锁反应。为了解决这个问题，我们将两个基于个体的模型结合起来，描述了salp个体的整个生命周期和磷虾个体的动态能量收支。由此产生的新模型PEKRIS(磷虾对海带的性能)模拟了在存在或不存在海带的不同叶绿素-a浓度下磷虾种群100年的变化。结果海带的存在显著影响了磷虾种群的丰度、平均体长和年产蛋量。另一方面，如果磷虾存在，海参密度不受影响。在每年最大叶绿素a密度变化期间，磷虾种群特性的中位数偏差为:磷虾密度为- 99.9%(- 234只/ 1000 m 3)，磷虾卵为- 100%(- 22,062个卵/ 1000 m 3)，磷虾平均长度为- 0.9% (- 0.3 mm)。结论如果两种物种在封闭空间内竞争相同的食物资源，海带似乎会抑制磷虾的数量。进一步的模拟研究应该调查，如果不同的浮游植物大小和磷虾的消费偏好，这种效应是否普遍存在。此外，海带直接捕食磷虾或吞食磷虾粪丸可能会改变食物竞争的影响程度。
{"title":"The impact of salps (Salpa thompsoni) on the Antarctic krill population (Euphausia superba): an individual-based modelling study","authors":"Bruno Walter Pietzsch, Aaron Schmidt, Jürgen Groeneveld, Dominik Bahlburg, Bettina Meyer, Uta Berger","doi":"10.1186/s13717-023-00462-9","DOIUrl":"https://doi.org/10.1186/s13717-023-00462-9","url":null,"abstract":"Abstract Background Krill ( Euphausia superba ) and salps ( Salpa thompsoni ) are key macrozooplankton grazers in the Southern Ocean ecosystem. However, due to differing habitat requirements, both species previously exhibited little spatial overlap. With ongoing climate change-induced seawater temperature increase and regional sea ice loss, salps can now extend their spatial distribution into historically krill-dominated areas and increase rapidly due to asexual reproduction when environmental conditions are favorable. Understanding the potential effects on krill is crucial, since krill is a species of exceptional trophic significance in the Southern Ocean food web. Negative impacts on krill could trigger cascading effects on its predators and prey. To address this question, we combined two individual-based models on salps and krill, which describe the whole life cycle of salp individuals and the dynamic energy budget of individual krill. The resulting new model PEKRIS ( PErformance of KRIll vs. Salps ) simulates a krill population for 100 years under varying chlorophyll-a concentrations in the presence or absence of salps. Results All of the investigated krill population properties (abundance, mean length, and yearly egg production) were significantly impacted by the presence of salps. On the other hand, salp density was not impacted if krill were present. The medians of krill population properties deviated during variable maximum chlorophyll-a density per year when salps were introduced by − 99.9% (− 234 individuals per 1000 m 3 ) for krill density, − 100% (− 22,062 eggs per 1000 m 3 ) for krill eggs and − 0.9% (− 0.3 mm) for mean length of krill. Conclusions If both species compete for the same food resource in a closed space, salps seem to inhibit krill populations. Further simulation studies should investigate whether this effect prevails if different phytoplankton sizes and consumption preferences of krill are implemented. Furthermore, direct predation of the two species or consumption of krill fecal pellets by salps could change the impact size of the food competition.","PeriodicalId":11419,"journal":{"name":"Ecological Processes","volume":"96 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135095059","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Background Mara River Basin is an ecologically fragile area in East Africa, with a pattern of alternating wet and dry seasons shaped by periodic precipitation. Considering the regional biological traits and climatic change, the vegetation's response to seasonal variation is complicated and frequently characterized by time lags. This study analyzed the variation of the Normalized Difference Vegetation Index (NDVI) and investigated its time lag to precipitation at the monthly scale. NDVI characteristic peaks were proposed from the perspective of seasonal mechanisms and were quantified to assess the lag effect. Results The results showed that the Anomaly Vegetation Index could identify low precipitation in 2006, 2009, and 2017. The NDVI showed an increasing trend in 75% of areas of the basin, while showed a decreased significance in 3.5% of areas, mainly in savannas. As to the time lag, the 1-month lag effect dominated most months, and the spatiotemporal disparities were noticeable. Another method considering the alternations of wet and dry seasons found that the time lag was approximately 30 days. Based on the time distribution of NDVI characteristic peaks, the average time lag was 35.5 days and increased with the range of seasons. Conclusions The findings confirmed an increasing trend of NDVI in most regions from 2001 to 2020, while the trends were most obvious in the downstream related to human activities. The results could reflect the time lag of NDVI response to precipitation, and the 1-month lag effect dominated in most months with spatial heterogeneity. Four NDVI characteristic peaks were found to be efficient indicators to assess the seasonal characteristics and had a great potential to quantify vegetation variation.
{"title":"Time lag effect of vegetation response to seasonal precipitation in the Mara River Basin","authors":"Shouming Feng, Zhenke Zhang, Shuhe Zhao, Xinya Guo, Wanyi Zhu, Priyanko Das","doi":"10.1186/s13717-023-00461-w","DOIUrl":"https://doi.org/10.1186/s13717-023-00461-w","url":null,"abstract":"Abstract Background Mara River Basin is an ecologically fragile area in East Africa, with a pattern of alternating wet and dry seasons shaped by periodic precipitation. Considering the regional biological traits and climatic change, the vegetation's response to seasonal variation is complicated and frequently characterized by time lags. This study analyzed the variation of the Normalized Difference Vegetation Index (NDVI) and investigated its time lag to precipitation at the monthly scale. NDVI characteristic peaks were proposed from the perspective of seasonal mechanisms and were quantified to assess the lag effect. Results The results showed that the Anomaly Vegetation Index could identify low precipitation in 2006, 2009, and 2017. The NDVI showed an increasing trend in 75% of areas of the basin, while showed a decreased significance in 3.5% of areas, mainly in savannas. As to the time lag, the 1-month lag effect dominated most months, and the spatiotemporal disparities were noticeable. Another method considering the alternations of wet and dry seasons found that the time lag was approximately 30 days. Based on the time distribution of NDVI characteristic peaks, the average time lag was 35.5 days and increased with the range of seasons. Conclusions The findings confirmed an increasing trend of NDVI in most regions from 2001 to 2020, while the trends were most obvious in the downstream related to human activities. The results could reflect the time lag of NDVI response to precipitation, and the 1-month lag effect dominated in most months with spatial heterogeneity. Four NDVI characteristic peaks were found to be efficient indicators to assess the seasonal characteristics and had a great potential to quantify vegetation variation.","PeriodicalId":11419,"journal":{"name":"Ecological Processes","volume":"111 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135591617","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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