Pub Date : 2024-06-25DOI: 10.1186/s13717-024-00512-w
Alejandro Brazeiro, Juan Olivera, Alejandra Betancourt, Ignacio Lado, David Romero, Federico Haretche, Alexandra Cravino
What factors, processes and mechanisms regulate invasive processes and their effects? This is one of the main questions addressed by the ecology of biological invasions. Ligustrum lucidum, a tree species native to East Asia, became an aggressive invader of subtropical and temperate forests around the world. We analyzed here the L. lucidum invasion in Uruguayan forests to determine the factors controlling two stages of the invasive process, the establishment, and the dominance. Establishment was assessed by the occurrence, measured in 1525, 1 × 1 km-cells, and dominance by remotely measuring the L. lucidum coverage at the forest canopy in 5554, 1 × 1 km-cells. The occurrence and dominance were modeled using Generalized Linear Models in function of independent environmental and geographic variables. Ligustrum lucidum has become established in 13.4% of the Uruguayan forests and has dominated the forest canopy in 1.2%. Our models explained 45% and 35% of the occurrence and dominance spatial variance respectively and detected in both cases strong diffusion patterns from the S-SW region to rest of Uruguay. Occurrence increased mainly in function of urban areas, and with the proximity to towns, probably because L. lucidum trees planted in gardens are seed sources, and near railways and highways, that could function as biological corridors. Occurrence also increased in loamy soils and near rivers, suggesting moisture conditions are favorable for establishment. Dominance increased with reduced forest area, in high productive soils and at higher altitudes. Moreover, dominance increased near urban areas, roads, and railways, as well as in highly afforested landscapes, and in loamy and low-rockiness soils. The invasion of Uruguayan forests by L. lucidum is in the spread and impact stages, currently in expansion from the invasion focus on the S-SW region, where the oldest urbanizations are settled, towards the rest of the country. The geographic proximity to the invasion focus is currently the main predictor of both L. lucidum establishment and dominance. Additionally, whereas establishment is manly facilitated by human infrastructures improving propagule pressure and dispersion, dominance is enhanced in small or fragmented forest patches, in rich-nutrient soils, and at higher altitudes, suggesting ecosystem resistance is also operating.
{"title":"Disentangling the invasion process of subtropical native forests of Uruguay by the exotic tree Ligustrum lucidum: establishment and dominance determinants","authors":"Alejandro Brazeiro, Juan Olivera, Alejandra Betancourt, Ignacio Lado, David Romero, Federico Haretche, Alexandra Cravino","doi":"10.1186/s13717-024-00512-w","DOIUrl":"https://doi.org/10.1186/s13717-024-00512-w","url":null,"abstract":"What factors, processes and mechanisms regulate invasive processes and their effects? This is one of the main questions addressed by the ecology of biological invasions. Ligustrum lucidum, a tree species native to East Asia, became an aggressive invader of subtropical and temperate forests around the world. We analyzed here the L. lucidum invasion in Uruguayan forests to determine the factors controlling two stages of the invasive process, the establishment, and the dominance. Establishment was assessed by the occurrence, measured in 1525, 1 × 1 km-cells, and dominance by remotely measuring the L. lucidum coverage at the forest canopy in 5554, 1 × 1 km-cells. The occurrence and dominance were modeled using Generalized Linear Models in function of independent environmental and geographic variables. Ligustrum lucidum has become established in 13.4% of the Uruguayan forests and has dominated the forest canopy in 1.2%. Our models explained 45% and 35% of the occurrence and dominance spatial variance respectively and detected in both cases strong diffusion patterns from the S-SW region to rest of Uruguay. Occurrence increased mainly in function of urban areas, and with the proximity to towns, probably because L. lucidum trees planted in gardens are seed sources, and near railways and highways, that could function as biological corridors. Occurrence also increased in loamy soils and near rivers, suggesting moisture conditions are favorable for establishment. Dominance increased with reduced forest area, in high productive soils and at higher altitudes. Moreover, dominance increased near urban areas, roads, and railways, as well as in highly afforested landscapes, and in loamy and low-rockiness soils. The invasion of Uruguayan forests by L. lucidum is in the spread and impact stages, currently in expansion from the invasion focus on the S-SW region, where the oldest urbanizations are settled, towards the rest of the country. The geographic proximity to the invasion focus is currently the main predictor of both L. lucidum establishment and dominance. Additionally, whereas establishment is manly facilitated by human infrastructures improving propagule pressure and dispersion, dominance is enhanced in small or fragmented forest patches, in rich-nutrient soils, and at higher altitudes, suggesting ecosystem resistance is also operating.","PeriodicalId":11419,"journal":{"name":"Ecological Processes","volume":"23 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141502502","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}
Globally increasing atmospheric nitrogen (N) deposition has altered soil phosphorus (P) transformations and availability, and thereby influenced structure and function of terrestrial ecosystems. Edaphic characteristics and chemical form of deposited N could be important factors determining impacts of N deposition on soil P transformations, yet the underlying mechanisms remain largely unknown. Objectives of this study were to examine how mineral-N and amino N differently affect P fractions, and identify key soil properties determining N addition impacts on soil P transformations. Considering that amino N is an important component of deposited N and forest soils vary greatly in different regions, the results of present study can guide the management of forests across different soils under ongoing N deposition scenarios. We conducted a 60-day laboratory experiment to investigate the effects of N addition (NH4NO3 and glycine) on soil P fractions and related biochemical properties in four representative forest soils (brown, yellow brown, aeolian sandy, and red soils) in China. Glycine and NH4NO3 were separately added at three rates (5, 10 and 20 g N m–2 yr–1). Firstly, the percent changes in organic P fractions with N addition were significantly greater than changes in inorganic P fractions across all soils. Secondly, the percent changes in P fractions with glycine and NH4NO3 additions were significantly correlated across all soils and treatments. However, glycine addition had significantly greater impacts on organic P fractions than NH4NO3 addition in the aeolian sandy and red soils with low organic carbon content. Thirdly, P fractions responded differently to N addition among the four soils. N-induced changes in microbial biomass and phosphatase activities, pH, exchangeable Ca2+ and Mg2+ contributed differently to the changes in P fractions with N addition in the four soils. The different responses of P fractions to N addition in the four soils were mainly generated by the differences in extent of microbial N limitation, acid buffering capacity, and cation exchange capacity among the soils. The different impacts of mineral and amino N on soil P fractions can be ascribed to their divergent effects on soil pH, microbial biomass and activities.
全球范围内不断增加的大气氮（N）沉积改变了土壤磷（P）的转化和供应，从而影响了陆地生态系统的结构和功能。土壤特性和沉积氮的化学形态可能是决定氮沉积对土壤磷转化影响的重要因素，但其潜在机制在很大程度上仍然未知。本研究的目的是考察矿物氮和氨基氮如何对磷组分产生不同影响，并确定决定氮添加对土壤磷转化影响的关键土壤特性。考虑到氨基氮是沉积氮的重要组成部分，而不同地区的森林土壤差异很大，本研究的结果可指导在持续氮沉积情况下不同土壤的森林管理。我们进行了一项为期 60 天的实验室实验，研究了氮添加（NH4NO3 和甘氨酸）对中国四种代表性森林土壤（棕壤、黄棕壤、风化沙土和红壤）中土壤磷组分及相关生化特性的影响。甘氨酸和 NH4NO3 的添加量分别为 5、10 和 20 g N m-2 yr-1。首先，在所有土壤中，添加氮后有机磷组分变化的百分比明显大于无机磷组分的变化。其次，在所有土壤和处理中，添加甘氨酸和 NH4NO3 时 P 分量变化的百分比明显相关。然而，在有机碳含量较低的风化沙土和红壤中，添加甘氨酸对有机磷组分的影响明显大于添加 NH4NO3。第三，四种土壤中的磷组分对氮添加的反应不同。氮引起的微生物生物量和磷酸酶活性、pH 值、可交换 Ca2+ 和 Mg2+ 的变化对四种土壤中添加氮后 P 组分的变化有不同的影响。四种土壤中 P 部分对氮添加的不同反应主要是由于微生物对氮的限制程度、酸缓冲能力和阳离子交换能力的不同造成的。矿物氮和氨基氮对土壤中磷组分的不同影响可归因于它们对土壤 pH 值、微生物生物量和活性的不同影响。
{"title":"Nitrogen addition has divergent effects on phosphorus fractions in four types of soils","authors":"Ping Zeng, Qiong Zhao, Jia-yu Hu, Xiang Zhang, Bing Mao, Qing-ye Sun, Wen-ge Wu","doi":"10.1186/s13717-024-00523-7","DOIUrl":"https://doi.org/10.1186/s13717-024-00523-7","url":null,"abstract":"Globally increasing atmospheric nitrogen (N) deposition has altered soil phosphorus (P) transformations and availability, and thereby influenced structure and function of terrestrial ecosystems. Edaphic characteristics and chemical form of deposited N could be important factors determining impacts of N deposition on soil P transformations, yet the underlying mechanisms remain largely unknown. Objectives of this study were to examine how mineral-N and amino N differently affect P fractions, and identify key soil properties determining N addition impacts on soil P transformations. Considering that amino N is an important component of deposited N and forest soils vary greatly in different regions, the results of present study can guide the management of forests across different soils under ongoing N deposition scenarios. We conducted a 60-day laboratory experiment to investigate the effects of N addition (NH4NO3 and glycine) on soil P fractions and related biochemical properties in four representative forest soils (brown, yellow brown, aeolian sandy, and red soils) in China. Glycine and NH4NO3 were separately added at three rates (5, 10 and 20 g N m–2 yr–1). Firstly, the percent changes in organic P fractions with N addition were significantly greater than changes in inorganic P fractions across all soils. Secondly, the percent changes in P fractions with glycine and NH4NO3 additions were significantly correlated across all soils and treatments. However, glycine addition had significantly greater impacts on organic P fractions than NH4NO3 addition in the aeolian sandy and red soils with low organic carbon content. Thirdly, P fractions responded differently to N addition among the four soils. N-induced changes in microbial biomass and phosphatase activities, pH, exchangeable Ca2+ and Mg2+ contributed differently to the changes in P fractions with N addition in the four soils. The different responses of P fractions to N addition in the four soils were mainly generated by the differences in extent of microbial N limitation, acid buffering capacity, and cation exchange capacity among the soils. The different impacts of mineral and amino N on soil P fractions can be ascribed to their divergent effects on soil pH, microbial biomass and activities.","PeriodicalId":11419,"journal":{"name":"Ecological Processes","volume":"135 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141259988","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 : 2024-05-14DOI: 10.1186/s13717-024-00520-w
Nur Hussain, Alemu Gonsamo, Shusen Wang, M. Altaf Arain
Deciduous forests in eastern North America experienced a widespread and intense spongy moth (Lymantria dispar) infestation in 2021. This study quantified the impact of this spongy moth infestation on carbon (C) cycle in forests across the Great Lakes region in Canada, utilizing high-resolution (10 × 10 m2) Sentinel-2 satellite remote sensing images and eddy covariance (EC) flux data. Study results showed a significant reduction in leaf area index (LAI) and gross primary productivity (GPP) values in deciduous and mixed forests in the region in 2021. Remote sensing derived, growing season mean LAI values of deciduous (mixed) forests were 3.66 (3.18), 2.74 (2.64), and 3.53 (2.94) m2 m−2 in 2020, 2021 and 2022, respectively, indicating about 24 (14)% reduction in LAI, as compared to pre- and post-infestation years. Similarly, growing season GPP values in deciduous (mixed) forests were 1338 (1208), 868 (932), and 1367 (1175) g C m−2, respectively in 2020, 2021 and 2022, showing about 35 (22)% reduction in GPP in 2021 as compared to pre- and post-infestation years. This infestation induced reduction in GPP of deciduous and mixed forests, when upscaled to whole study area (178,000 km2), resulted in 21.1 (21.4) Mt of C loss as compared to 2020 (2022), respectively. It shows the large scale of C losses caused by this infestation in Canadian Great Lakes region. The methods developed in this study offer valuable tools to assess and quantify natural disturbance impacts on the regional C balance of forest ecosystems by integrating field observations, high-resolution remote sensing data and models. Study results will also help in developing sustainable forest management practices to achieve net-zero C emission goals through nature-based climate change solutions.
{"title":"Assessment of spongy moth infestation impacts on forest productivity and carbon loss using the Sentinel-2 satellite remote sensing and eddy covariance flux data","authors":"Nur Hussain, Alemu Gonsamo, Shusen Wang, M. Altaf Arain","doi":"10.1186/s13717-024-00520-w","DOIUrl":"https://doi.org/10.1186/s13717-024-00520-w","url":null,"abstract":"Deciduous forests in eastern North America experienced a widespread and intense spongy moth (Lymantria dispar) infestation in 2021. This study quantified the impact of this spongy moth infestation on carbon (C) cycle in forests across the Great Lakes region in Canada, utilizing high-resolution (10 × 10 m2) Sentinel-2 satellite remote sensing images and eddy covariance (EC) flux data. Study results showed a significant reduction in leaf area index (LAI) and gross primary productivity (GPP) values in deciduous and mixed forests in the region in 2021. Remote sensing derived, growing season mean LAI values of deciduous (mixed) forests were 3.66 (3.18), 2.74 (2.64), and 3.53 (2.94) m2 m−2 in 2020, 2021 and 2022, respectively, indicating about 24 (14)% reduction in LAI, as compared to pre- and post-infestation years. Similarly, growing season GPP values in deciduous (mixed) forests were 1338 (1208), 868 (932), and 1367 (1175) g C m−2, respectively in 2020, 2021 and 2022, showing about 35 (22)% reduction in GPP in 2021 as compared to pre- and post-infestation years. This infestation induced reduction in GPP of deciduous and mixed forests, when upscaled to whole study area (178,000 km2), resulted in 21.1 (21.4) Mt of C loss as compared to 2020 (2022), respectively. It shows the large scale of C losses caused by this infestation in Canadian Great Lakes region. The methods developed in this study offer valuable tools to assess and quantify natural disturbance impacts on the regional C balance of forest ecosystems by integrating field observations, high-resolution remote sensing data and models. Study results will also help in developing sustainable forest management practices to achieve net-zero C emission goals through nature-based climate change solutions.","PeriodicalId":11419,"journal":{"name":"Ecological Processes","volume":"61 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140931654","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 : 2024-05-11DOI: 10.1186/s13717-024-00518-4
Feng Jiang, Tao Pu, Zi-Jing Xue, Yan-Wei Ma, Xiao-Yi Shi, Fu-Xi Shi
Stable carbon isotope composition (δ13Cp) can be used to estimate the changes in intrinsic water use efficiency (iWUE) in plants, which helps us to better understand plants’ response strategies to climate change. This study focused on the variations in δ13Cp and iWUE for the different life-form plants (i.e., herbs, shrubs, and trees) along an altitudinal gradient (3300, 3600, 3900, 4100, 4300, and 4500 m) on the eastern slope of Yulong Snow Mountain, southeastern margin of the Qinghai-Tibet Plateau. The response mechanisms of δ13Cp and iWUE for different life-form plants to altitude were thoroughly analyzed in this mountain ecosystem. The δ13Cp values of plants on the eastern slopes of Yulong Snow Mountain ranged from − 30.4‰ to − 26.55‰, with a mean of − 28.02‰, indicating a dominance of C3 plants. The δ13Cp and iWUE values varied among different life-form plants in the order of herbs > shrubs > trees, particularly in 3600, 3900, and 4300 m. The δ13Cp and iWUE values for herbs and shrubs increased with altitude and were mainly controlled by air temperature. The two parameters for trees exhibited a trend of initial decrease followed by an increase with altitude. Below 3900 m, the δ13Cp and iWUE values decreased with altitude, influenced by soil moisture. However, above 3900 m, the two parameters increased with altitude, mainly regulated by air temperature. In addition, iWUE was positively correlated with leaf P content but negatively correlated with leaf N:P ratio, especially for herbs and trees, suggesting that P plays a key role in modulating iWUE in this region. The differentiated responses of water availability for different life-form plants to a higher altitudinal gradient are regulated by air temperature, soil moisture, and leaf P content in the Yulong Snow Mountain. These results provide valuable insights into understanding the water–carbon relationships in high-altitude ecosystems.
稳定碳同位素组成（δ13Cp）可用于估算植物内在水分利用效率（iWUE）的变化，从而帮助我们更好地了解植物对气候变化的应对策略。本研究重点研究了青藏高原东南缘玉龙雪山东坡不同生命形式植物（即草本、灌木和乔木）的δ13Cp和iWUE在海拔梯度（3300、3600、3900、4100、4300和4500米）上的变化。在该高山生态系统中，深入分析了不同生命形式植物的δ13Cp和iWUE对海拔高度的响应机制。玉龙雪山东坡植物的δ13Cp值在-30.4‰至-26.55‰之间，平均值为-28.02‰，表明C3植物占优势。不同生命形式植物的δ13Cp和iWUE值依次为草本植物>灌木>乔木，尤其是在海拔3600米、3900米和4300米的地区。乔木的这两个参数则呈现出先降低后随海拔升高而升高的趋势。在海拔 3900 米以下，受土壤湿度的影响，δ13Cp 和 iWUE 值随海拔升高而降低。然而，在海拔 3900 米以上，这两个参数随海拔升高而升高，主要受气温影响。此外，iWUE 与叶片 P 含量呈正相关，但与叶片 N:P 比率呈负相关，尤其是草本植物和乔木，这表明 P 在调节该地区 iWUE 方面起着关键作用。在玉龙雪山，气温、土壤水分和叶片钾含量对不同生命形式植物的水分供应对较高海拔梯度的差异响应具有调节作用。这些结果为理解高海拔生态系统的水碳关系提供了宝贵的见解。
{"title":"Stable carbon isotope composition and intrinsic water use efficiency in plants along an altitudinal gradient on the eastern slope of Yulong Snow Mountain, China","authors":"Feng Jiang, Tao Pu, Zi-Jing Xue, Yan-Wei Ma, Xiao-Yi Shi, Fu-Xi Shi","doi":"10.1186/s13717-024-00518-4","DOIUrl":"https://doi.org/10.1186/s13717-024-00518-4","url":null,"abstract":"Stable carbon isotope composition (δ13Cp) can be used to estimate the changes in intrinsic water use efficiency (iWUE) in plants, which helps us to better understand plants’ response strategies to climate change. This study focused on the variations in δ13Cp and iWUE for the different life-form plants (i.e., herbs, shrubs, and trees) along an altitudinal gradient (3300, 3600, 3900, 4100, 4300, and 4500 m) on the eastern slope of Yulong Snow Mountain, southeastern margin of the Qinghai-Tibet Plateau. The response mechanisms of δ13Cp and iWUE for different life-form plants to altitude were thoroughly analyzed in this mountain ecosystem. The δ13Cp values of plants on the eastern slopes of Yulong Snow Mountain ranged from − 30.4‰ to − 26.55‰, with a mean of − 28.02‰, indicating a dominance of C3 plants. The δ13Cp and iWUE values varied among different life-form plants in the order of herbs > shrubs > trees, particularly in 3600, 3900, and 4300 m. The δ13Cp and iWUE values for herbs and shrubs increased with altitude and were mainly controlled by air temperature. The two parameters for trees exhibited a trend of initial decrease followed by an increase with altitude. Below 3900 m, the δ13Cp and iWUE values decreased with altitude, influenced by soil moisture. However, above 3900 m, the two parameters increased with altitude, mainly regulated by air temperature. In addition, iWUE was positively correlated with leaf P content but negatively correlated with leaf N:P ratio, especially for herbs and trees, suggesting that P plays a key role in modulating iWUE in this region. The differentiated responses of water availability for different life-form plants to a higher altitudinal gradient are regulated by air temperature, soil moisture, and leaf P content in the Yulong Snow Mountain. These results provide valuable insights into understanding the water–carbon relationships in high-altitude ecosystems.","PeriodicalId":11419,"journal":{"name":"Ecological Processes","volume":"34 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140931789","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}
Understanding of the ratio of photosynthetic photon flux density (Qp) to global solar radiation (Rs) (Qp/Rs) is crucial for applying Rs to ecology-related studies. Previous studies reported Qp/Rs and its variations based on measurements from a single observatory tower, instead of multi-site-based measurements over complex terrains. This may neglect spatial heterogeneity in the terrain, creating a gap in an understanding of how terrain affects Qp/Rs and how this effect interacts with meteorological factors. Here the Qingyuan Ker Towers (three towers in a valley with different terrains: T1, T2, and T3) were utilized to measure Qp and Rs over mountainous forests of Northeast China. An airborne LiDAR system was used to generate a digital elevation model, and sky view factor of sectors (SVFs) divided from the field of view of tower’s pyranometer was calculated as a topographic factor to explain the variations of Qp/Rs. The results identified significant differences in Qp/Rs of the three towers at both daily and half-hour scales, with larger differences on clear days than on overcast days. Qp/Rs was positively correlated with SVFs of T1 and T3, while this correlation was negative with that of T2. The effect of SVFs on Qp/Rs interacted with clearness index, water vapor pressure and solar zenith angle. Random forest-based importance assessment demonstrated that explanation (R2) on Qp/Rs was improved when SVFs was included in the predictor variable set, indicating that incorporating terrain effects enhances the prediction accuracy of Qp/Rs. The improvement in the R2 values was more pronounced on clear days than on overcast days, suggesting that the effect of terrain on Qp/Rs depended on sky conditions. All findings suggested that Qp/Rs is affected by terrain, and integrating terrain information into existing Qp/Rs models is a feasible solution to improve Qp/Rs estimates in mountainous areas.
{"title":"Ratio of photosynthetically active radiation to global solar radiation above forest canopy in complex terrain: measurements and analyses based on Qingyuan Ker Towers","authors":"Shuangtian Li, Qiaoling Yan, Tian Gao, Xingchang Wang, Qingwei Wang, Fengyuan Yu, Deliang Lu, Huaqi Liu, Jinxin Zhang, Jiaojun Zhu","doi":"10.1186/s13717-024-00514-8","DOIUrl":"https://doi.org/10.1186/s13717-024-00514-8","url":null,"abstract":"Understanding of the ratio of photosynthetic photon flux density (Qp) to global solar radiation (Rs) (Qp/Rs) is crucial for applying Rs to ecology-related studies. Previous studies reported Qp/Rs and its variations based on measurements from a single observatory tower, instead of multi-site-based measurements over complex terrains. This may neglect spatial heterogeneity in the terrain, creating a gap in an understanding of how terrain affects Qp/Rs and how this effect interacts with meteorological factors. Here the Qingyuan Ker Towers (three towers in a valley with different terrains: T1, T2, and T3) were utilized to measure Qp and Rs over mountainous forests of Northeast China. An airborne LiDAR system was used to generate a digital elevation model, and sky view factor of sectors (SVFs) divided from the field of view of tower’s pyranometer was calculated as a topographic factor to explain the variations of Qp/Rs. The results identified significant differences in Qp/Rs of the three towers at both daily and half-hour scales, with larger differences on clear days than on overcast days. Qp/Rs was positively correlated with SVFs of T1 and T3, while this correlation was negative with that of T2. The effect of SVFs on Qp/Rs interacted with clearness index, water vapor pressure and solar zenith angle. Random forest-based importance assessment demonstrated that explanation (R2) on Qp/Rs was improved when SVFs was included in the predictor variable set, indicating that incorporating terrain effects enhances the prediction accuracy of Qp/Rs. The improvement in the R2 values was more pronounced on clear days than on overcast days, suggesting that the effect of terrain on Qp/Rs depended on sky conditions. All findings suggested that Qp/Rs is affected by terrain, and integrating terrain information into existing Qp/Rs models is a feasible solution to improve Qp/Rs estimates in mountainous areas.","PeriodicalId":11419,"journal":{"name":"Ecological Processes","volume":"117 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140931629","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 : 2024-05-06DOI: 10.1186/s13717-024-00496-7
Rita Maria Lopez Laphitz, María Verónica Arana, Santiago Agustín Varela, Leandro Aníbal Becker, Carolina Soliani, María Marta Azpilicueta, Paula Marchelli, Nicolás Bellora
Deciphering the genetic architecture of drought tolerance could allow the candidate genes identification responding to water stress. In the Andean Patagonian forest, the genus Nothofagus represents an ecologically relevant species to be included in different genomic studies. These studies are scarce in South American ecosystems however represent an important source of genomic data in order to interpret future climate-change environment scenarios of these emblematic forests. Here, we achieved the assemblage of the transcriptome of N. alpina while searching for key genes of activated or suppressed metabolic pathways in response to drought stress. De novo transcriptome assembly resulted in 104,030 transcripts. Following confirmation of drought conditions, based on reduction of leaf water potential and stomatal conductance, a differential gene expression analysis resulted in 2720 significantly expressed genes (1601 up-regulated and 1119 down-regulated). Enrichment analysis (over-representation analysis and gene set enrichment analysis) resulted in more than one hundred stress-responsive term ontologies (i.e. biological processes) and pathways. Terms such as response to abscisic acid and pathways such as plant hormone signal transduction or starch and sucrose metabolism were over-represented. Protein–protein interaction assessment resulted in networks with significantly expressed top common hub gene clusters (e.g. plant-type cell wall biogenesis among down-regulated or ABA-signalling among up-regulated). These networks evidenced important regulators at gene expression such as transcriptional factors. Responses of N. alpina seedlings to drought stress were evidenced by the activation of several genes linked to GO biological processes and KEGG pathways, which were mainly based on over-expression of specific protein kinases, phosphatases, synthases and transcription factors. This suggests an up-regulation of signalling pathways, triggered through plant hormones such as abscisic acid or auxin, which could counteract the osmotic stress created as a probable immediate response to drought. On the other hand, groups of carbon fixation genes related to the galactose metabolism, photosynthesis, secondary wall biogenesis, and fatty acid biosynthesis degradation were down-regulated under drought. Overall, our results provide new genomic data for understanding how non-model long-lived trees of Patagonian forests would acclimate to environmental changes.
破译耐旱性的基因结构可以识别响应水胁迫的候选基因。在安第斯巴塔哥尼亚森林中，Nothofagus 属是与生态相关的物种，应纳入不同的基因组研究。这些研究在南美生态系统中很少见，但却是解读这些标志性森林未来气候变化环境情景的重要基因组数据来源。在这里，我们完成了阿尔卑斯山红豆杉（N. alpina）转录组的组装，同时寻找干旱胁迫下激活或抑制代谢途径的关键基因。从头开始的转录本组组装产生了 104,030 个转录本。根据叶片水势和气孔导度的降低确认干旱条件后，差异基因表达分析得出了 2720 个显著表达的基因（1601 个上调，1119 个下调）。富集分析（过度呈现分析和基因组富集分析）得出了一百多个胁迫响应术语本体（即生物过程）和通路。对脱落酸的反应等术语和植物激素信号转导或淀粉和蔗糖代谢等途径的代表性过高。蛋白质-蛋白质相互作用评估产生了具有显著表达的顶级共同中心基因簇网络（例如，下调的植物类型细胞壁生物发生或上调的 ABA 信号转导）。这些网络证明了基因表达的重要调节因子，如转录因子。N. alpina幼苗对干旱胁迫的反应表现为与 GO 生物过程和 KEGG 通路相关的多个基因被激活，这些基因主要基于特定蛋白激酶、磷酸酶、合成酶和转录因子的过度表达。这表明，通过脱落酸或辅酶等植物激素触发的信号通路上调，可以抵消可能对干旱做出直接反应而产生的渗透胁迫。另一方面，与半乳糖代谢、光合作用、次生壁生物生成和脂肪酸生物合成降解有关的碳固定基因组在干旱条件下下调。总之，我们的研究结果为了解巴塔哥尼亚森林中的非模式长寿树如何适应环境变化提供了新的基因组数据。
{"title":"Transcriptomic responses to drought stress in the Patagonian southern beech Nothofagus alpina","authors":"Rita Maria Lopez Laphitz, María Verónica Arana, Santiago Agustín Varela, Leandro Aníbal Becker, Carolina Soliani, María Marta Azpilicueta, Paula Marchelli, Nicolás Bellora","doi":"10.1186/s13717-024-00496-7","DOIUrl":"https://doi.org/10.1186/s13717-024-00496-7","url":null,"abstract":"Deciphering the genetic architecture of drought tolerance could allow the candidate genes identification responding to water stress. In the Andean Patagonian forest, the genus Nothofagus represents an ecologically relevant species to be included in different genomic studies. These studies are scarce in South American ecosystems however represent an important source of genomic data in order to interpret future climate-change environment scenarios of these emblematic forests. Here, we achieved the assemblage of the transcriptome of N. alpina while searching for key genes of activated or suppressed metabolic pathways in response to drought stress. De novo transcriptome assembly resulted in 104,030 transcripts. Following confirmation of drought conditions, based on reduction of leaf water potential and stomatal conductance, a differential gene expression analysis resulted in 2720 significantly expressed genes (1601 up-regulated and 1119 down-regulated). Enrichment analysis (over-representation analysis and gene set enrichment analysis) resulted in more than one hundred stress-responsive term ontologies (i.e. biological processes) and pathways. Terms such as response to abscisic acid and pathways such as plant hormone signal transduction or starch and sucrose metabolism were over-represented. Protein–protein interaction assessment resulted in networks with significantly expressed top common hub gene clusters (e.g. plant-type cell wall biogenesis among down-regulated or ABA-signalling among up-regulated). These networks evidenced important regulators at gene expression such as transcriptional factors. Responses of N. alpina seedlings to drought stress were evidenced by the activation of several genes linked to GO biological processes and KEGG pathways, which were mainly based on over-expression of specific protein kinases, phosphatases, synthases and transcription factors. This suggests an up-regulation of signalling pathways, triggered through plant hormones such as abscisic acid or auxin, which could counteract the osmotic stress created as a probable immediate response to drought. On the other hand, groups of carbon fixation genes related to the galactose metabolism, photosynthesis, secondary wall biogenesis, and fatty acid biosynthesis degradation were down-regulated under drought. Overall, our results provide new genomic data for understanding how non-model long-lived trees of Patagonian forests would acclimate to environmental changes.","PeriodicalId":11419,"journal":{"name":"Ecological Processes","volume":"114 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140888919","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 : 2024-05-01DOI: 10.1186/s13717-024-00515-7
Junjie Lei, Changli Zeng, Lv Zhang, Xiaogang Wang, Chanhua Ma, Tao Zhou, Benjamin Laffitte, Ke Luo, Zhihan Yang, Xiaolu Tang
Soil organic carbon (SOC) is a critical component of the global carbon cycle, and an accurate estimate of regional SOC stock (SOCS) would significantly improve our understanding of SOC sequestration and cycles. Zoige Plateau, locating in the northeastern Qinghai-Tibet Plateau, has the largest alpine marsh wetland worldwide and exhibits a high sensitivity to climate fluctuations. Despite an increasing use of optical remote sensing in predicting regional SOCS, optical remote sensing has obvious limitations in the Zoige Plateau due to highly cloudy weather, and knowledge of on the spatial patterns of SOCS is limited. Therefore, in the current study, the spatial distributions of SOCS within 100 cm were predicted using an XGBoost model—a machine learning approach, by integrating Sentinel-1, Sentinel-2 and field observations in the Zoige Plateau. The results showed that SOC content exhibited vertical distribution patterns within 100 cm, with the highest SOC content in topsoil. The tenfold cross-validation approach showed that XGBoost model satisfactorily predicted the spatial patterns of SOCS with a model efficiency of 0.59 and a root mean standard error of 95.2 Mg ha−1. Predicted SOCS showed a distinct spatial heterogeneity in the Zoige Plateau, with an average of 355.7 ± 123.1 Mg ha−1 within 100 cm and totaled 0.27 × 109 Mg carbon. High SOC content in topsoil highlights the high risks of significant carbon loss from topsoil due to human activities in the Zoige Plateau. Combining Sentinel-1 and Sentinel-2 satisfactorily predicted SOCS using the XGBoost model, which demonstrates the importance of selecting modeling approaches and satellite images to improve efficiency in predicting SOCS distribution at a fine spatial resolution of 10 m. Furthermore, the study emphasizes the potential of radar (Sentinel-1) in developing SOCS mapping, with the newly developed fine-resolution mapping having important applications in land management, ecological restoration, and protection efforts in the Zoige Plateau.
{"title":"Prediction of soil organic carbon stock combining Sentinel-1 and Sentinel-2 images in the Zoige Plateau, the northeastern Qinghai-Tibet Plateau","authors":"Junjie Lei, Changli Zeng, Lv Zhang, Xiaogang Wang, Chanhua Ma, Tao Zhou, Benjamin Laffitte, Ke Luo, Zhihan Yang, Xiaolu Tang","doi":"10.1186/s13717-024-00515-7","DOIUrl":"https://doi.org/10.1186/s13717-024-00515-7","url":null,"abstract":"Soil organic carbon (SOC) is a critical component of the global carbon cycle, and an accurate estimate of regional SOC stock (SOCS) would significantly improve our understanding of SOC sequestration and cycles. Zoige Plateau, locating in the northeastern Qinghai-Tibet Plateau, has the largest alpine marsh wetland worldwide and exhibits a high sensitivity to climate fluctuations. Despite an increasing use of optical remote sensing in predicting regional SOCS, optical remote sensing has obvious limitations in the Zoige Plateau due to highly cloudy weather, and knowledge of on the spatial patterns of SOCS is limited. Therefore, in the current study, the spatial distributions of SOCS within 100 cm were predicted using an XGBoost model—a machine learning approach, by integrating Sentinel-1, Sentinel-2 and field observations in the Zoige Plateau. The results showed that SOC content exhibited vertical distribution patterns within 100 cm, with the highest SOC content in topsoil. The tenfold cross-validation approach showed that XGBoost model satisfactorily predicted the spatial patterns of SOCS with a model efficiency of 0.59 and a root mean standard error of 95.2 Mg ha−1. Predicted SOCS showed a distinct spatial heterogeneity in the Zoige Plateau, with an average of 355.7 ± 123.1 Mg ha−1 within 100 cm and totaled 0.27 × 109 Mg carbon. High SOC content in topsoil highlights the high risks of significant carbon loss from topsoil due to human activities in the Zoige Plateau. Combining Sentinel-1 and Sentinel-2 satisfactorily predicted SOCS using the XGBoost model, which demonstrates the importance of selecting modeling approaches and satellite images to improve efficiency in predicting SOCS distribution at a fine spatial resolution of 10 m. Furthermore, the study emphasizes the potential of radar (Sentinel-1) in developing SOCS mapping, with the newly developed fine-resolution mapping having important applications in land management, ecological restoration, and protection efforts in the Zoige Plateau.","PeriodicalId":11419,"journal":{"name":"Ecological Processes","volume":"147 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140834139","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 : 2024-05-01DOI: 10.1186/s13717-024-00516-6
Xiaotong Wu, Qixing Zhou, Hui Zeng, Xiangang Hu
Microbial communities are crucial for ecosystems. A central goal of microbial ecological research is to simplify the biodiversity in natural environments and quantify the functional roles to explore how the ecosystems respond under different environmental conditions. However, the research on the stability and dynamics of lake microbes in response to repeated warming stress is limited. To exclude confounding environmental factors, we conducted a 20-day repeated warming simulation experiment to examine the composition and function dynamics of lake microbial communities. Experimental warming significantly altered the community structure of bacteria instead of fungi. Microbial community structure, together with microbial biomass, jointly regulated the function of microbial communities. The plummeting of aerobic denitrifiers Pseudomonadaceae decreased by 99% (P < 0.001) after high temperature, leading to reduced microbial nitrogen metabolism on nitrogen respiration and nitrate respiration. Under warming conditions, the microbial community with higher adaptability showed more positive correlations and less competitive relationships in co-occurrence networks to acclimate to warming. Microbiome composition controlled carbon and nitrogen metabolism, thus determining lake microbial communities’ adaptability to heat stress. This study extended our insights on the lake microbial community response and adaptability under warming drivers.
{"title":"Lake microbiome composition determines community adaptability to warming perturbations","authors":"Xiaotong Wu, Qixing Zhou, Hui Zeng, Xiangang Hu","doi":"10.1186/s13717-024-00516-6","DOIUrl":"https://doi.org/10.1186/s13717-024-00516-6","url":null,"abstract":"Microbial communities are crucial for ecosystems. A central goal of microbial ecological research is to simplify the biodiversity in natural environments and quantify the functional roles to explore how the ecosystems respond under different environmental conditions. However, the research on the stability and dynamics of lake microbes in response to repeated warming stress is limited. To exclude confounding environmental factors, we conducted a 20-day repeated warming simulation experiment to examine the composition and function dynamics of lake microbial communities. Experimental warming significantly altered the community structure of bacteria instead of fungi. Microbial community structure, together with microbial biomass, jointly regulated the function of microbial communities. The plummeting of aerobic denitrifiers Pseudomonadaceae decreased by 99% (P < 0.001) after high temperature, leading to reduced microbial nitrogen metabolism on nitrogen respiration and nitrate respiration. Under warming conditions, the microbial community with higher adaptability showed more positive correlations and less competitive relationships in co-occurrence networks to acclimate to warming. Microbiome composition controlled carbon and nitrogen metabolism, thus determining lake microbial communities’ adaptability to heat stress. This study extended our insights on the lake microbial community response and adaptability under warming drivers.","PeriodicalId":11419,"journal":{"name":"Ecological Processes","volume":"60 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140833991","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 : 2024-04-10DOI: 10.1186/s13717-024-00504-w
Kanhaiya Shah, Gyan Prakash Sharma, R. Sagar
Hyptis suaveolens (L.) Poit., native to the American tropics, is a pantropical annual plant and a major invasive species throughout India. It was anticipated that the availability of sunlight, coupled with its superior reproductive potential, persistent propagule bank, and dispersal ability, could lead to an increase in the growth and spread of this invader, thus potentially impeding herbaceous growth and diversity in non-native areas. Clarifying its ecological fitness and competitive performance will be useful to manage the spread of H. suaveolens in natural ecosystems that are facing a wide range of anthropogenic pressures. The present study is a three-tier experiment. In the first tier, a field study was conducted to assess the patterns of H. suaveolens abundance and herbaceous species diversity in response to light availability (sun, 842–1072 µmol m–2 s−1 and shade 253–341 µmol m–2 s−1) in the tropical dry deciduous ecosystems in the Vindhyan highlands, India. Furthermore, the impact of H. suaveolens abundance on the resident native and non-native species abundance and diversity was also studied. In the second tier, a randomized common garden experiment was conducted to understand the trait fitness of H. suaveolens in sun (940 µmol m–2 s−1) and shade (300 µmol m–2 s−1) conditions. In the third tier, a plant growth chamber experiment with high-light (940 µmol m–2 s−1) and low-light (300 µmol m–2 s−1) treatments was done to learn how H. suaveolens partitions its biomass between aboveground and belowground plant parts. The field study indicated that the sunlit areas had a higher abundance of H. suaveolens and a lower diversity of resident herbaceous species than the shaded areas. The common garden experiment showed that sun-dwelling H. suaveolens individuals performed better in germinative, vegetative, eco-physiological, and reproductive traits than the shade-dwelling individuals. The growth chamber experiment exhibited that plants grown in high-light environment had greater seed germination, seedling recruitment, and aboveground biomass than those grown in low-light environment, whereas plants grown in low-light environment exhibited a higher root mass ratio than the high-light individuals. These results suggest that H. suaveolens individuals mask the understory vegetation owing to higher seedling recruitment, relative growth rate, photosynthetic performance, resource acquisition-allocation, and reproductive output in response to high-light conditions. The study concludes that light significantly controls the invasive population dynamics of H. suaveolens in dry deciduous forests. In high-light areas, H. suaveolens populations dominate the forest understory with suboptimal shade tolerance. In shade environment, H. suaveolens maintains a persistent soil seed bank along with ‘Oskar individuals’ that become active in response to high-light availability. The modus operandi is a ‘sit and wait’ strategy. The current study provides insights on prioriti
Hyptis suaveolens (L.) Poit.原产于美洲热带地区，是泛热带一年生植物，也是印度的主要入侵物种。预计充足的阳光，加上其优越的繁殖潜力、持久的繁殖体库和传播能力，会导致这种入侵者的生长和传播速度加快，从而有可能阻碍非本地地区草本植物的生长和多样性。明确其生态适应性和竞争表现将有助于管理 H. suaveolens 在面临各种人为压力的自然生态系统中的传播。本研究是一项三层实验。第一层是实地研究，目的是评估印度温迪亚高原热带干燥落叶生态系统中 H. suaveolens 丰度和草本物种多样性对光照（阳光，842-1072 µmol m-2 s-1 和阴凉处 253-341 µmol m-2 s-1）的响应模式。此外，还研究了 H. suaveolens 的丰度对本地和非本地常驻物种丰度和多样性的影响。第二层是随机普通花园实验，以了解 H. suaveolens 在阳光（940 µmol m-2 s-1）和阴凉（300 µmol m-2 s-1）条件下的性状适应性。第三层是植物生长室实验，采用高光（940 µmol m-2 s-1）和低光（300 µmol m-2 s-1）处理，以了解 H. suaveolens 如何在地上部分和地下部分之间分配生物量。实地研究表明，与阴暗区域相比，阳光照射区域的 H. suaveolens 数量较多，而常住草本物种的多样性较低。普通花园实验表明，在发芽、无性繁殖、生态生理和繁殖特性方面，在阳光下生活的 H. suaveolens 个体都优于在阴凉处生活的个体。生长室实验表明，在高光环境下生长的植株在种子萌发率、幼苗移栽率和地上生物量方面均高于在低光环境下生长的植株，而在低光环境下生长的植株在根系质量比方面高于高光环境下的植株。这些结果表明，H. suaveolens个体由于在高光照条件下具有较高的幼苗新陈代谢、相对生长率、光合作用表现、资源获取-分配和生殖输出能力，从而掩盖了林下植被。研究得出结论，光照能显著控制 H. suaveolens 在干燥落叶林中的入侵种群动态。在高光照地区，H. suaveolens种群以次优的耐荫性在林下占据主导地位。在荫蔽环境中，H. suaveolens与 "奥斯卡个体 "一起维持着一个持久的土壤种子库，这些个体会在高光照条件下变得活跃起来。其工作方式是 "坐等 "策略。目前的研究为确定 H. suaveolens 管理区域的优先次序提供了见解，这将有可能降低生物入侵对热带地区本地物种多样性造成的风险。
{"title":"An arrow in the quiver: evaluating the performance of Hyptis suaveolens (L.) Poit. in different light levels","authors":"Kanhaiya Shah, Gyan Prakash Sharma, R. Sagar","doi":"10.1186/s13717-024-00504-w","DOIUrl":"https://doi.org/10.1186/s13717-024-00504-w","url":null,"abstract":"Hyptis suaveolens (L.) Poit., native to the American tropics, is a pantropical annual plant and a major invasive species throughout India. It was anticipated that the availability of sunlight, coupled with its superior reproductive potential, persistent propagule bank, and dispersal ability, could lead to an increase in the growth and spread of this invader, thus potentially impeding herbaceous growth and diversity in non-native areas. Clarifying its ecological fitness and competitive performance will be useful to manage the spread of H. suaveolens in natural ecosystems that are facing a wide range of anthropogenic pressures. The present study is a three-tier experiment. In the first tier, a field study was conducted to assess the patterns of H. suaveolens abundance and herbaceous species diversity in response to light availability (sun, 842–1072 µmol m–2 s−1 and shade 253–341 µmol m–2 s−1) in the tropical dry deciduous ecosystems in the Vindhyan highlands, India. Furthermore, the impact of H. suaveolens abundance on the resident native and non-native species abundance and diversity was also studied. In the second tier, a randomized common garden experiment was conducted to understand the trait fitness of H. suaveolens in sun (940 µmol m–2 s−1) and shade (300 µmol m–2 s−1) conditions. In the third tier, a plant growth chamber experiment with high-light (940 µmol m–2 s−1) and low-light (300 µmol m–2 s−1) treatments was done to learn how H. suaveolens partitions its biomass between aboveground and belowground plant parts. The field study indicated that the sunlit areas had a higher abundance of H. suaveolens and a lower diversity of resident herbaceous species than the shaded areas. The common garden experiment showed that sun-dwelling H. suaveolens individuals performed better in germinative, vegetative, eco-physiological, and reproductive traits than the shade-dwelling individuals. The growth chamber experiment exhibited that plants grown in high-light environment had greater seed germination, seedling recruitment, and aboveground biomass than those grown in low-light environment, whereas plants grown in low-light environment exhibited a higher root mass ratio than the high-light individuals. These results suggest that H. suaveolens individuals mask the understory vegetation owing to higher seedling recruitment, relative growth rate, photosynthetic performance, resource acquisition-allocation, and reproductive output in response to high-light conditions. The study concludes that light significantly controls the invasive population dynamics of H. suaveolens in dry deciduous forests. In high-light areas, H. suaveolens populations dominate the forest understory with suboptimal shade tolerance. In shade environment, H. suaveolens maintains a persistent soil seed bank along with ‘Oskar individuals’ that become active in response to high-light availability. The modus operandi is a ‘sit and wait’ strategy. The current study provides insights on prioriti","PeriodicalId":11419,"journal":{"name":"Ecological Processes","volume":"89 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140579978","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 : 2024-03-29DOI: 10.1186/s13717-024-00507-7
Jawad Ali Shah, Wenfei Liu, Saif Ullah, Honglang Duan, Fangfang Shen, Yingchun Liao, Guomin Huang, Jianping Wu
The prevalence of understory removal and anthropogenic nitrogen (N) deposition has significantly altered the ecological processes of forest ecosystems at both regional and global scales. However, it remains a pressing challenge to understand how N deposition and understory removal affect leaf nutrient dynamics, nutrient resorption, litter decomposition, and their linkages for better managing forest ecosystems under nutrient imbalances induced by N enrichment. To address this research gap, a field manipulation experiment was carried out in a subtropical Cunninghamia lanceolata plantation with four treatments including: control (CK), canopy N addition (CN), understory removal (UR), and canopy N addition plus understory removal (CN × UR). Green and senesced leaf N and phosphorus (P) concentrations, N and P resorption efficiencies, litter decomposition, and their correlations were measured. The results revealed that the average N concentrations of green early and late leaves in UR were increased by 6.61 and 18.89% compared to CK. UR had the highest whereas CN had the lowest P concentrations in green leaves across the two sampling seasons. Following this, UR, leaf type, season, and their interactions significantly affected leaf N, P, and N:P (P < 0.05). The highest leaf N resorption (32.68%) and P resorption efficiencies (63.96%) were recorded in UR. Litter decomposition was significantly retarded in UR (P < 0.01) relative to CN. The regression analysis demonstrated that leaf nutrient status was significantly interconnected with leaf nutrient resorption efficiencies. In addition, leaf nutrient dynamics were strongly correlated with litter nutrients, indicating that both were coupled. These findings can deepen our knowledge of biogeochemical cycling and reveal contrasting nutrient-acquisition strategies on N and P limitation in response to UR and CN. Considering the P limitation, it is important to note that P was resorbed more efficiently, illustrating a remarkable nutrient preservation approach for nutrient-limitations. Resorption may be a crucial mechanism for keeping nutrients in these forests, so better understory management practices are required to prevent reliance on external nutrient pools. Overall, this study sheds meaningful insights into the ability of forest adaptation in response to global climatic change.
林下植物移除和人为氮（N）沉积的普遍存在极大地改变了区域和全球范围内森林生态系统的生态过程。然而，如何理解氮沉积和林下植物移除如何影响叶片养分动态、养分吸收、枯落物分解以及它们之间的联系，以便在氮富集导致养分失衡的情况下更好地管理森林生态系统，仍然是一项紧迫的挑战。针对这一研究空白，我们在亚热带杉木人工林中开展了一项田间操作实验，共设四个处理，包括对照（CK）、冠层氮添加（CN）、林下植物移除（UR）和冠层氮添加加林下植物移除（CN × UR）。对绿叶和衰老叶片的氮和磷浓度、氮和磷的重吸收效率、枯落物分解及其相关性进行了测定。结果表明，与 CK 相比，UR 早期和晚期绿叶的平均氮浓度分别增加了 6.61% 和 18.89%。在两个采样季中，UR 的绿叶中 P 浓度最高，而 CN 的 P 浓度最低。随后，UR、叶片类型、季节及其交互作用对叶片氮、磷和 N:P 有显著影响（P < 0.05）。UR 的叶片氮吸收率（32.68%）和磷吸收率（63.96%）最高。相对于 CN，UR 的腐叶分解速度明显较慢（P < 0.01）。回归分析表明，叶片养分状况与叶片养分重吸收效率密切相关。此外，叶片养分动态与枯落物养分密切相关，表明二者是耦合的。这些发现加深了我们对生物地球化学循环的认识，并揭示了UR和CN对氮和磷限制的不同养分获取策略。考虑到钾的限制，重要的是要注意到钾被更有效地吸收，这说明了在养分限制中一种显著的养分保存方法。吸收可能是这些森林保持养分的关键机制，因此需要更好的林下管理方法，以防止对外部养分池的依赖。总之，这项研究对森林适应全球气候变化的能力提出了有意义的见解。
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