Background: Forest ecosystems are in the spotlight for their potential to mitigate anthropogenic carbon dioxide (CO2) emissions through net photosynthesis. However, this mitigation potential can be counteracted by respiratory losses, e.g., from soils and the forest floor. With global warming, soil respiration (SR) rates are expected to increase, unless acclimation occurs. Using manual and automated chambers as well as a below-canopy eddy-covariance system, we quantified SR and forest floor net CO2 exchange (NEEff) for 13 years throughout an 18-year study period (2006-2010, 2015-2016, 2018-2023) in a mixed deciduous forest ecosystem in Switzerland. We identified the contribution of environmental drivers for SR and NEEff using Extreme Gradient Boosting models and Shapley additive explanations (SHAP) analyses and assessed the long-term temperature sensitivity of SR and NEEff.
Results: Over the 18-year study period, soil temperature increased significantly and was the main driver of both SR and NEEff, explaining over 50% of their temporal variability. Differences in drivers and magnitudes of SR vs. NEEff were only found in early spring, when the forest floor vegetation showed net CO2 uptake. Finally, we found no evidence that SR or NEEff (at mean annual temperatures) had increased between 2006 and 2023. Similarly, no significant change in the temperature sensitivity of SR and NEEff was observed.
Conclusions: Combining multiple techniques to assess long-term responses of CO2 fluxes to environmental conditions with machine learning approaches enhanced our understanding of forest responses to climate change. Moreover, our findings suggest that soil and forest floor respiration already acclimated to warmer conditions, highly relevant for predicting future mitigation potentials of forest ecosystems.
{"title":"Soil and forest floor respiration already acclimated to increasing temperatures in a mixed deciduous forest.","authors":"Liliana Scapucci, Luana Krebs, Susanne Burri, Lukas Hörtnagl, Nina Buchmann","doi":"10.1186/s13717-025-00639-4","DOIUrl":"10.1186/s13717-025-00639-4","url":null,"abstract":"<p><strong>Background: </strong>Forest ecosystems are in the spotlight for their potential to mitigate anthropogenic carbon dioxide (CO<sub>2</sub>) emissions through net photosynthesis. However, this mitigation potential can be counteracted by respiratory losses, e.g., from soils and the forest floor. With global warming, soil respiration (SR) rates are expected to increase, unless acclimation occurs. Using manual and automated chambers as well as a below-canopy eddy-covariance system, we quantified SR and forest floor net CO<sub>2</sub> exchange (NEE<sub>ff</sub>) for 13 years throughout an 18-year study period (2006-2010, 2015-2016, 2018-2023) in a mixed deciduous forest ecosystem in Switzerland. We identified the contribution of environmental drivers for SR and NEE<sub>ff</sub> using Extreme Gradient Boosting models and Shapley additive explanations (SHAP) analyses and assessed the long-term temperature sensitivity of SR and NEE<sub>ff</sub>.</p><p><strong>Results: </strong>Over the 18-year study period, soil temperature increased significantly and was the main driver of both SR and NEE<sub>ff</sub>, explaining over 50% of their temporal variability. Differences in drivers and magnitudes of SR vs. NEE<sub>ff</sub> were only found in early spring, when the forest floor vegetation showed net CO<sub>2</sub> uptake. Finally, we found no evidence that SR or NEE<sub>ff</sub> (at mean annual temperatures) had increased between 2006 and 2023. Similarly, no significant change in the temperature sensitivity of SR and NEE<sub>ff</sub> was observed.</p><p><strong>Conclusions: </strong>Combining multiple techniques to assess long-term responses of CO<sub>2</sub> fluxes to environmental conditions with machine learning approaches enhanced our understanding of forest responses to climate change. Moreover, our findings suggest that soil and forest floor respiration already acclimated to warmer conditions, highly relevant for predicting future mitigation potentials of forest ecosystems.</p>","PeriodicalId":11419,"journal":{"name":"Ecological Processes","volume":"14 1","pages":"71"},"PeriodicalIF":3.9,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12399736/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144991700","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-01Epub Date: 2025-09-23DOI: 10.1186/s13717-025-00646-5
Liam Baron-Preston, James D Roth, John H Markham
Background: Soil nutrient availability is a limiting factor for tundra productivity. Therefore, consumer-driven alteration of nutrient availability can have a large effect on tundra communities. Previous work has demonstrated that Arctic foxes (Vulpes lagopus) act as ecosystem engineers in tundra heath communities by altering plant composition and increasing plant biomass on their dens, which then increases snow depth. To test the ability of increased nutrients and deeper snow to cause the ecosystem effects observed on fox dens, we set up a nutrient addition and snow fencing experiment on tundra heath in Wapusk National Park, Canada.
Results: Changes in experimental plots were mainly driven by fertilizer application, not snow depth. After 2 years, the fertilizer plots were invaded by a dune grass (Elymus mollis), which increased to 12% cover by the end of the experiment, which is typical of fox dens. After 4 years, total plant cover was 26% higher on the fertilizer plots than on the control plots. After 7 years of treatments, the plots receiving both fertilizer and snow fencing had the greatest shift in plant species composition, although they still lacked the tall willow shrubs typical of fox dens. Fertilized plots and dens had five times more arthropods than control plots. Most wildlife, except caribou (Rangifer tarandus), spent more time on fertilized plots in years when they were abundant, with Canada geese (Branta canadensis) being present 20 times longer in fertilizer plots. Collared lemmings (Dicrostonyx richardsoni) also preferred fertilized plots in the summer, but winter use was more pronounced on snow fenced and fertilized plots, where they produced 20 latrines per plot in a peak population year.
Conclusions: These results demonstrate that the nutrient limitation in tundra vegetation makes tundra ecosystems vulnerable to changes in nutrient availability, with changes in plant abundance and composition leading to increased animal activity, that has the potential to create a positive feedback in ecosystem productivity.
Supplementary information: The online version contains supplementary material available at 10.1186/s13717-025-00646-5.
{"title":"Ecosystem engineering of tundra heath by Arctic fox (<i>Vulpes lagopus</i>) is driven by nutrient additions.","authors":"Liam Baron-Preston, James D Roth, John H Markham","doi":"10.1186/s13717-025-00646-5","DOIUrl":"10.1186/s13717-025-00646-5","url":null,"abstract":"<p><strong>Background: </strong>Soil nutrient availability is a limiting factor for tundra productivity. Therefore, consumer-driven alteration of nutrient availability can have a large effect on tundra communities. Previous work has demonstrated that Arctic foxes (<i>Vulpes lagopus</i>) act as ecosystem engineers in tundra heath communities by altering plant composition and increasing plant biomass on their dens, which then increases snow depth. To test the ability of increased nutrients and deeper snow to cause the ecosystem effects observed on fox dens, we set up a nutrient addition and snow fencing experiment on tundra heath in Wapusk National Park, Canada.</p><p><strong>Results: </strong>Changes in experimental plots were mainly driven by fertilizer application, not snow depth. After 2 years, the fertilizer plots were invaded by a dune grass (<i>Elymus mollis</i>), which increased to 12% cover by the end of the experiment, which is typical of fox dens. After 4 years, total plant cover was 26% higher on the fertilizer plots than on the control plots. After 7 years of treatments, the plots receiving both fertilizer and snow fencing had the greatest shift in plant species composition, although they still lacked the tall willow shrubs typical of fox dens. Fertilized plots and dens had five times more arthropods than control plots. Most wildlife, except caribou (<i>Rangifer tarandus</i>), spent more time on fertilized plots in years when they were abundant, with Canada geese (<i>Branta canadensis</i>) being present 20 times longer in fertilizer plots. Collared lemmings (<i>Dicrostonyx richardsoni</i>) also preferred fertilized plots in the summer, but winter use was more pronounced on snow fenced and fertilized plots, where they produced 20 latrines per plot in a peak population year.</p><p><strong>Conclusions: </strong>These results demonstrate that the nutrient limitation in tundra vegetation makes tundra ecosystems vulnerable to changes in nutrient availability, with changes in plant abundance and composition leading to increased animal activity, that has the potential to create a positive feedback in ecosystem productivity.</p><p><strong>Supplementary information: </strong>The online version contains supplementary material available at 10.1186/s13717-025-00646-5.</p>","PeriodicalId":11419,"journal":{"name":"Ecological Processes","volume":"14 1","pages":"80"},"PeriodicalIF":3.9,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12457229/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145148427","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-01Epub Date: 2025-03-03DOI: 10.1186/s13717-025-00587-z
Swantje Gebhardt, Jerry van Dijk, Marjolein E Lof, Martin J Wassen, Martha Bakker
Background: The restoration of natural landscape elements is a frequently adopted pathway to improve wild pollinator abundance, diversity, and their pollination services in intensively used agricultural landscapes. However, pollinators in the intended refuges can become exposed to agrochemicals when foraging in surrounding agricultural fields. In order to effectively design pollinator conservation measures such as habitat restoration or pesticide reduction schemes, the effect of land use configuration on pesticide exposure and pollination service requires further investigation.
Methods: We developed a pollination model that extends existing approaches by simulating both pollination flights and concurrent pollinator exposure to toxic pesticides, enabling the estimation of pesticide impacts on pollination services. We calculated pollination service and pollinator health for a set of artificial landscapes, which varied in the percentage of pollinator habitat and agriculture, in the clustering of these land uses, as well as in the pollinator mortality hazard arising from the pesticides applied on agriculture.
Results: Our results show that in landscapes with less than 10% habitat and highly toxic pesticides, pollination services are mostly safeguarded by compact patches of habitat, as this configuration shelters more habitat from pesticide exposure. With increasing habitat amount or with pesticide applications causing less than 50% mortality in pollinators, more dispersed patches of habitat achieve a better pollination service for the landscape. We further tested the effect of pesticide application for different foraging ranges in a more realistic land use scenario. For pollinators with shorter foraging ranges, pesticide exposure from the immediate surroundings determines the achieved pollination. For species with longer foraging ranges, the availability of resources and the application of pesticides at landscape scale controls the pollination.
Conclusion: Our study highlights the importance of assessing spatial configuration effects on pesticide exposure for local pollinators. By applying these insights, land managers can devise land use arrangements to protect pollinator habitats and establish buffer zones to support pollinator activity in pesticide-intensive landscapes. As current guidelines largely lack spatially-explicit measures, we suggest to direct future research and policies towards the underlying spatial processes and their facilitation on parcel, farm, and landscape scale.
Supplementary information: The online version contains supplementary material available at 10.1186/s13717-025-00587-z.
{"title":"Understanding interactive effects between habitat configuration and pesticide use for pollination: towards better informed landscape management.","authors":"Swantje Gebhardt, Jerry van Dijk, Marjolein E Lof, Martin J Wassen, Martha Bakker","doi":"10.1186/s13717-025-00587-z","DOIUrl":"10.1186/s13717-025-00587-z","url":null,"abstract":"<p><strong>Background: </strong>The restoration of natural landscape elements is a frequently adopted pathway to improve wild pollinator abundance, diversity, and their pollination services in intensively used agricultural landscapes. However, pollinators in the intended refuges can become exposed to agrochemicals when foraging in surrounding agricultural fields. In order to effectively design pollinator conservation measures such as habitat restoration or pesticide reduction schemes, the effect of land use configuration on pesticide exposure and pollination service requires further investigation.</p><p><strong>Methods: </strong>We developed a pollination model that extends existing approaches by simulating both pollination flights and concurrent pollinator exposure to toxic pesticides, enabling the estimation of pesticide impacts on pollination services. We calculated pollination service and pollinator health for a set of artificial landscapes, which varied in the percentage of pollinator habitat and agriculture, in the clustering of these land uses, as well as in the pollinator mortality hazard arising from the pesticides applied on agriculture.</p><p><strong>Results: </strong>Our results show that in landscapes with less than 10% habitat and highly toxic pesticides, pollination services are mostly safeguarded by compact patches of habitat, as this configuration shelters more habitat from pesticide exposure. With increasing habitat amount or with pesticide applications causing less than 50% mortality in pollinators, more dispersed patches of habitat achieve a better pollination service for the landscape. We further tested the effect of pesticide application for different foraging ranges in a more realistic land use scenario. For pollinators with shorter foraging ranges, pesticide exposure from the immediate surroundings determines the achieved pollination. For species with longer foraging ranges, the availability of resources and the application of pesticides at landscape scale controls the pollination.</p><p><strong>Conclusion: </strong>Our study highlights the importance of assessing spatial configuration effects on pesticide exposure for local pollinators. By applying these insights, land managers can devise land use arrangements to protect pollinator habitats and establish buffer zones to support pollinator activity in pesticide-intensive landscapes. As current guidelines largely lack spatially-explicit measures, we suggest to direct future research and policies towards the underlying spatial processes and their facilitation on parcel, farm, and landscape scale.</p><p><strong>Supplementary information: </strong>The online version contains supplementary material available at 10.1186/s13717-025-00587-z.</p>","PeriodicalId":11419,"journal":{"name":"Ecological Processes","volume":"14 1","pages":"25"},"PeriodicalIF":4.6,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11876248/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143566346","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-19DOI: 10.1186/s13717-024-00542-4
Yang Yu, Xin Chen, Yin Yi, Chunwang Xiao
The potential effects of global warming on soil fungal communities and their functions remain uncertain. To address this issue, we investigated the effects of 3-year simulated field warming on the community and function of fungi in a temperate steppe of Inner Mongolia, northern China. The diversity and structure of the fungal community were measured by high-throughput sequencing. The functionality of fungal communities was identified by comparison with the ITS reference database. Our results showed that warming did not affect the diversity of fungi, but significantly increased the complexity of the fungal community, with fungal taxa more closely associating with each other. We observed that plant pathogens and arbuscular mycorrhizal fungi were the most abundant functional groups. Meanwhile, warming significantly decreased the relative abundance of animal pathogens. Warming significantly increased the complexity of the fungal community, with soil pH being the main factor affecting soil fungal function. Our findings emphasize that the response of the fungal community and its functional groups to warming has significant implications for ecosystem biogeochemical cycling.
全球变暖对土壤真菌群落及其功能的潜在影响仍不确定。为了解决这个问题，我们研究了 3 年模拟野外气候变暖对中国北方内蒙古温带大草原真菌群落及其功能的影响。通过高通量测序测量了真菌群落的多样性和结构。通过与 ITS 参考数据库进行比较，确定了真菌群落的功能。结果表明，气候变暖并不影响真菌的多样性，但显著增加了真菌群落的复杂性，真菌类群之间的联系更加紧密。我们观察到，植物病原菌和丛枝菌根真菌是最丰富的功能群。同时，气候变暖显著降低了动物病原体的相对丰度。气候变暖明显增加了真菌群落的复杂性，而土壤酸碱度是影响土壤真菌功能的主要因素。我们的研究结果表明，真菌群落及其功能群对气候变暖的反应对生态系统的生物地球化学循环具有重要影响。
{"title":"Effects of warming on soil fungal community and its function in a temperate steppe","authors":"Yang Yu, Xin Chen, Yin Yi, Chunwang Xiao","doi":"10.1186/s13717-024-00542-4","DOIUrl":"https://doi.org/10.1186/s13717-024-00542-4","url":null,"abstract":"The potential effects of global warming on soil fungal communities and their functions remain uncertain. To address this issue, we investigated the effects of 3-year simulated field warming on the community and function of fungi in a temperate steppe of Inner Mongolia, northern China. The diversity and structure of the fungal community were measured by high-throughput sequencing. The functionality of fungal communities was identified by comparison with the ITS reference database. Our results showed that warming did not affect the diversity of fungi, but significantly increased the complexity of the fungal community, with fungal taxa more closely associating with each other. We observed that plant pathogens and arbuscular mycorrhizal fungi were the most abundant functional groups. Meanwhile, warming significantly decreased the relative abundance of animal pathogens. Warming significantly increased the complexity of the fungal community, with soil pH being the main factor affecting soil fungal function. Our findings emphasize that the response of the fungal community and its functional groups to warming has significant implications for ecosystem biogeochemical cycling.","PeriodicalId":11419,"journal":{"name":"Ecological Processes","volume":"213 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142254908","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}
Caloric value is an important indicator of grassland ecosystem function, but the response of caloric value to nitrogen (N) addition and mowing is still unclear. We explored the adaptive changes of plant caloric value and energy standing crop along a N addition gradient after six-year NH4NO3 addition and mowing treatments in an Inner Mongolian temperate meadow steppe in northern China. We found that the response of plant caloric value to N addition at different organizational levels was diverse. The caloric value of legumes increased linearly with N addition rates. The caloric value of grasses exhibited a non-linear response trend, initially increasing followed by saturation or decrease, with a N response threshold present. Due to the dominance of grass species, the caloric value at the community level followed a similar pattern to that of the grasses along the N addition gradient. Under mowing, the caloric value of plants at each organizational level increased and usually mowing enhanced the N response threshold. Amongst these, the N response threshold of Leymus chinensis increased from 3.302 to 5.443 g N m−2 yr−1, grasses increased from 4.414 to 5.746 g N m−2 yr−1, and community increased from 5.373 to 9.216 g N m−2 yr−1. Under non-mowing treatment, the N response thresholds of the most dominant species, Leymus chinensis, and community energy standing crop were 10.001 and 15.119 g N m−2 yr−1, respectively. Under mowing, the energy standing crops showed a linear increasing trend. N response thresholds of plant caloric value and energy standing crop vary at different organizational levels (community > functional group > species). The results reveal varying regulatory capabilities of plants on the ecological environment at different organizational levels. These findings enhance our understanding of plant-environment interactions in grassland ecosystems under N deposition from an energy perspective, which is of great significance to clarify the response mechanism of grassland ecosystem structure and function to N deposition.
热量值是衡量草原生态系统功能的重要指标，但热量值对氮素添加和刈割的响应尚不清楚。我们探讨了在中国北方内蒙古温带草甸草原上，经过六年的NH4NO3添加和刈割处理后，植物热量值和常温作物能量在氮添加梯度上的适应性变化。我们发现，植物热值对不同组织水平氮添加量的响应是多样的。豆科植物的热值随着氮添加量的增加而线性增加。禾本科植物的热量值呈现非线性响应趋势，最初增加，随后饱和或减少，存在氮响应阈值。由于禾本科物种占优势，群落层面的热量值与禾本科物种的热量值在氮添加梯度上的模式相似。在刈割的情况下，每个组织水平的植物热量值都会增加，通常刈割会提高氮反应阈值。其中，禾本科植物的氮响应阈值从 3.302 g N m-2 yr-1 提高到 5.443 g N m-2 yr-1，禾本科植物从 4.414 g N m-2 yr-1 提高到 5.746 g N m-2 yr-1，群落从 5.373 g N m-2 yr-1 提高到 9.216 g N m-2 yr-1。在非刈割处理下，最优势物种禾本科植物和群落常绿能源作物的氮响应阈值分别为 10.001 和 15.119 g N m-2 yr-1。在刈割条件下，立地能源作物的氮响应阈值呈线性上升趋势。在不同的组织水平（群落 > 功能群 > 物种）上，植物热量值和常温作物能量的氮响应阈值各不相同。这些结果揭示了植物在不同组织水平上对生态环境的不同调控能力。这些发现从能量角度加深了我们对氮沉降条件下草地生态系统中植物与环境相互作用的理解，对阐明草地生态系统结构和功能对氮沉降的响应机制具有重要意义。
{"title":"Non-linear response of plant caloric value to N addition and mowing treatments in a meadow steppe","authors":"Jiaqi Ye, Shuai Wu, Yu Mo, Siqi Yang, Yu Zhao, Jing Zhang, Xiaotao Lü, Guojiao Yang, Xingguo Han, Cunzhu Liang, Zhenghai Li, Yajing Bao","doi":"10.1186/s13717-024-00544-2","DOIUrl":"https://doi.org/10.1186/s13717-024-00544-2","url":null,"abstract":"Caloric value is an important indicator of grassland ecosystem function, but the response of caloric value to nitrogen (N) addition and mowing is still unclear. We explored the adaptive changes of plant caloric value and energy standing crop along a N addition gradient after six-year NH4NO3 addition and mowing treatments in an Inner Mongolian temperate meadow steppe in northern China. We found that the response of plant caloric value to N addition at different organizational levels was diverse. The caloric value of legumes increased linearly with N addition rates. The caloric value of grasses exhibited a non-linear response trend, initially increasing followed by saturation or decrease, with a N response threshold present. Due to the dominance of grass species, the caloric value at the community level followed a similar pattern to that of the grasses along the N addition gradient. Under mowing, the caloric value of plants at each organizational level increased and usually mowing enhanced the N response threshold. Amongst these, the N response threshold of Leymus chinensis increased from 3.302 to 5.443 g N m−2 yr−1, grasses increased from 4.414 to 5.746 g N m−2 yr−1, and community increased from 5.373 to 9.216 g N m−2 yr−1. Under non-mowing treatment, the N response thresholds of the most dominant species, Leymus chinensis, and community energy standing crop were 10.001 and 15.119 g N m−2 yr−1, respectively. Under mowing, the energy standing crops showed a linear increasing trend. N response thresholds of plant caloric value and energy standing crop vary at different organizational levels (community > functional group > species). The results reveal varying regulatory capabilities of plants on the ecological environment at different organizational levels. These findings enhance our understanding of plant-environment interactions in grassland ecosystems under N deposition from an energy perspective, which is of great significance to clarify the response mechanism of grassland ecosystem structure and function to N deposition.","PeriodicalId":11419,"journal":{"name":"Ecological Processes","volume":"14 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142254907","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}
Extreme rainfall and flooding events are projected to increase in frequency and disturb biogeochemical cycles such as the nitrogen (N) cycle. By combining trees and grasses, silvopastoral agroforestry is expected to increase the stability of this cycle in response to flooding. However, little is known about the response of nitrification to flooding in silvopastoral systems. Aim of this study was to assess nitrification stability in response to flooding and identify the main causal relations that drive it in temperate silvopastures. The nitrification stability (i.e., resistance and resilience) was assessed in two silvopastoral systems (i.e., hedgerows and alley cropping) at three positions relative to the trees. The resistance and resilience of nitrification potential were measured in the laboratory after four weeks of flooding stress and four weeks after the end of the stress, respectively. For the first time, we used multigroup latent structural equation modeling (ML-SEM) to explore the spatial structure of causal relations between nitrification stability and soil properties across all positions of the two silvopastoral systems. Tree rows of both systems favored nitrification resistance, while the mean nitrification potential under flooded conditions was on average 27% and 35% higher as compared to non-stressed soils at the two positions assessed in the grass alleys. ML-SEM revealed that the causal relations that explained these results differed between the two systems. The ML-SEM models tested were unable to explain the causal relations in the hedgerow system. However, the model that considered a covariance between soil physical properties and soil resources availability (model A) was able to explain them in the alley-cropping system. It revealed that causal relations explaining nitrification stability varied according to the position relative to the trees: in the tree rows nitrification stability was associated with higher soil organic carbon concentration and earthworm abundance; in the grass alleys it was associated with higher soil organic carbon concentration and soil bulk density. This study indicates that silvopastoral systems help regulate the N cycle near the trees. The results further imply that improvements in soil organic carbon concentration and soil bulk density favor the regulation of N-related processes in grasslands.
{"title":"Spatial patterns of causality in temperate silvopastoral systems: a perspective on nitrification stability in response to flooding","authors":"Romane Mettauer, Mathieu Emily, Zita Bednar-Konski, Anaïs Widmer, Olivier Godinot, Lukas Beule, Edith Le Cadre","doi":"10.1186/s13717-024-00538-0","DOIUrl":"https://doi.org/10.1186/s13717-024-00538-0","url":null,"abstract":"Extreme rainfall and flooding events are projected to increase in frequency and disturb biogeochemical cycles such as the nitrogen (N) cycle. By combining trees and grasses, silvopastoral agroforestry is expected to increase the stability of this cycle in response to flooding. However, little is known about the response of nitrification to flooding in silvopastoral systems. Aim of this study was to assess nitrification stability in response to flooding and identify the main causal relations that drive it in temperate silvopastures. The nitrification stability (i.e., resistance and resilience) was assessed in two silvopastoral systems (i.e., hedgerows and alley cropping) at three positions relative to the trees. The resistance and resilience of nitrification potential were measured in the laboratory after four weeks of flooding stress and four weeks after the end of the stress, respectively. For the first time, we used multigroup latent structural equation modeling (ML-SEM) to explore the spatial structure of causal relations between nitrification stability and soil properties across all positions of the two silvopastoral systems. Tree rows of both systems favored nitrification resistance, while the mean nitrification potential under flooded conditions was on average 27% and 35% higher as compared to non-stressed soils at the two positions assessed in the grass alleys. ML-SEM revealed that the causal relations that explained these results differed between the two systems. The ML-SEM models tested were unable to explain the causal relations in the hedgerow system. However, the model that considered a covariance between soil physical properties and soil resources availability (model A) was able to explain them in the alley-cropping system. It revealed that causal relations explaining nitrification stability varied according to the position relative to the trees: in the tree rows nitrification stability was associated with higher soil organic carbon concentration and earthworm abundance; in the grass alleys it was associated with higher soil organic carbon concentration and soil bulk density. This study indicates that silvopastoral systems help regulate the N cycle near the trees. The results further imply that improvements in soil organic carbon concentration and soil bulk density favor the regulation of N-related processes in grasslands.","PeriodicalId":11419,"journal":{"name":"Ecological Processes","volume":"42 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142254912","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 : 2024-09-11DOI: 10.1186/s13717-024-00547-z
Yiming Hu, Zhifeng Ding, Huijian Hu, Luke Gibson, Dan Liang, Zhixin Zhou, Jianchao Liang, Brett R. Scheffers
Mountain ecosystems are critical hotspots of global biodiversity, yet the dynamics of community assembly along their elevational gradients are not well understood. This gap is primarily due to the complexity of environmental and biotic interactions that influence species distribution and community structure. Although extensive research has been conducted on certain taxa, such as small mammals and bats, comprehensive studies encompassing entire mammal assemblages are lacking. Our research aims to bridge this gap by examining the taxonomic, phylogenetic, and functional diversity, as well as the assemblage structures of mammal communities across elevational gradients in the Central and East Himalayas, exploring how diverse ecological and evolutionary processes impact community assembly. We analyzed mammal elevational diversity patterns using species richness, functional diversity (FD), and phylogenetic diversity (PD). We compared the observed values of community structure, such as mean pairwise phylogenetic distance (MPD) and mean pairwise functional distance (MFD), with null-model corrected effect sizes to identify patterns and processes of community assembly. Using structural equation modeling and hierarchical partitioning, we investigated the relationships between climate, productivity, and various facets of diversity, describing the organization of each component across different elevations. Taxonomic, functional, and phylogenetic diversity generally decreased with elevation but showed varied patterns such as mid-elevation peaks, low-elevation plateaus, or monotonic declines across different regions. Richness-controlled functional diversity increased towards mid-low elevations and decreased at higher elevations in both regions, whereas richness-controlled phylogenetic diversity lacked consistent patterns. Phylogenetic structures tended to cluster from mid to high elevations, indicating closer relationships than those observed in random communities, likely due to significant environmental turnover near tree lines. Functional structure showed greater clustering at high elevations and increased over-dispersion at lower elevations, suggesting that species are more functionally similar than expected at higher elevations and more diverse at lower elevations. Our results revealed that environmental factors, evolutionary histories, and trait-driven ecological processes collectively shape species richness along these gradients. Our results showed incongruent community structures across phylogenetic and functional diversity. Generally, functional traits are closely linked to environmental conditions, reducing the chance of observing traits that are misaligned with their surroundings. Species with similar ecological roles or distinct evolutionary lineages often show convergent adaptations to highland environments. Additionally, our findings emphasize that community assembly varies with the biogeography and diversification history of individual mountain ran
{"title":"Functional and phylogenetic structure of mammals along elevational gradients in the Central and East Himalayas","authors":"Yiming Hu, Zhifeng Ding, Huijian Hu, Luke Gibson, Dan Liang, Zhixin Zhou, Jianchao Liang, Brett R. Scheffers","doi":"10.1186/s13717-024-00547-z","DOIUrl":"https://doi.org/10.1186/s13717-024-00547-z","url":null,"abstract":"Mountain ecosystems are critical hotspots of global biodiversity, yet the dynamics of community assembly along their elevational gradients are not well understood. This gap is primarily due to the complexity of environmental and biotic interactions that influence species distribution and community structure. Although extensive research has been conducted on certain taxa, such as small mammals and bats, comprehensive studies encompassing entire mammal assemblages are lacking. Our research aims to bridge this gap by examining the taxonomic, phylogenetic, and functional diversity, as well as the assemblage structures of mammal communities across elevational gradients in the Central and East Himalayas, exploring how diverse ecological and evolutionary processes impact community assembly. We analyzed mammal elevational diversity patterns using species richness, functional diversity (FD), and phylogenetic diversity (PD). We compared the observed values of community structure, such as mean pairwise phylogenetic distance (MPD) and mean pairwise functional distance (MFD), with null-model corrected effect sizes to identify patterns and processes of community assembly. Using structural equation modeling and hierarchical partitioning, we investigated the relationships between climate, productivity, and various facets of diversity, describing the organization of each component across different elevations. Taxonomic, functional, and phylogenetic diversity generally decreased with elevation but showed varied patterns such as mid-elevation peaks, low-elevation plateaus, or monotonic declines across different regions. Richness-controlled functional diversity increased towards mid-low elevations and decreased at higher elevations in both regions, whereas richness-controlled phylogenetic diversity lacked consistent patterns. Phylogenetic structures tended to cluster from mid to high elevations, indicating closer relationships than those observed in random communities, likely due to significant environmental turnover near tree lines. Functional structure showed greater clustering at high elevations and increased over-dispersion at lower elevations, suggesting that species are more functionally similar than expected at higher elevations and more diverse at lower elevations. Our results revealed that environmental factors, evolutionary histories, and trait-driven ecological processes collectively shape species richness along these gradients. Our results showed incongruent community structures across phylogenetic and functional diversity. Generally, functional traits are closely linked to environmental conditions, reducing the chance of observing traits that are misaligned with their surroundings. Species with similar ecological roles or distinct evolutionary lineages often show convergent adaptations to highland environments. Additionally, our findings emphasize that community assembly varies with the biogeography and diversification history of individual mountain ran","PeriodicalId":11419,"journal":{"name":"Ecological Processes","volume":"746 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142227436","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 : 2024-09-10DOI: 10.1186/s13717-024-00546-0
J. Silverio Avila-Sanchez, Humberto L. Perotto-Baldivieso, Lori D. Massey, J. Alfonso Ortega-S, Leonard A. Brennan, Fidel Hernández
Monitoring forage in livestock operations is critical to sustainable rangeland management of soil and ecological processes that provide both livestock and wildlife habitat. Traditional ground-based sampling methods have been widely used and provide valuable information; however, they are time-consuming, labor-intensive, and limited in their ability to capture larger extents of the spatial and temporal dynamics of rangeland ecosystems. Drones provide a solution to collect data to larger extents than field-based methods and with higher-resolution than traditional remote sensing platforms. Our objectives were to (1) assess the accuracy of vegetation cover height in grasses using drones, (2) quantify the spatial distribution of vegetation cover height in grazed and non-grazed pastures during the dormant (fall–winter) and growing seasons (spring–summer), and (3) evaluate the spatial distribution of vegetation cover height as a proxy for northern bobwhite (Colinus virginianus) habitat in South Texas. We achieved this by very fine scale drone-derived imagery and using class level landscape metrics to assess vegetation cover height configuration. Estimated heights from drone imagery had a significant relationship with the field height measurements in September (r2 = 0.83; growing season) and February (r2 = 0.77; dormant season). Growing season pasture maintained residual landscape habitat configuration adequate for bobwhites throughout the fall and winter of 2022–2023 following grazing. Dormant season pasture had an increase in bare ground cover, and a shift from many large patches of tall herbaceous cover (40–120 cm) to few large patches of low herbaceous cover (5–30 cm) (p < 0.05). Drones provided high-resolution imagery that allowed us to assess the spatial and temporal changes of vertical herbaceous vegetation structure in a semi-arid rangeland subject to grazing. This study shows how drone imagery can be beneficial for wildlife conservation and management by providing insights into changes in fine-scale vegetation spatial and temporal heterogeneity from livestock grazing.
{"title":"Fine spatial scale assessment of structure and configuration of vegetation cover for northern bobwhites in grazed pastures","authors":"J. Silverio Avila-Sanchez, Humberto L. Perotto-Baldivieso, Lori D. Massey, J. Alfonso Ortega-S, Leonard A. Brennan, Fidel Hernández","doi":"10.1186/s13717-024-00546-0","DOIUrl":"https://doi.org/10.1186/s13717-024-00546-0","url":null,"abstract":"Monitoring forage in livestock operations is critical to sustainable rangeland management of soil and ecological processes that provide both livestock and wildlife habitat. Traditional ground-based sampling methods have been widely used and provide valuable information; however, they are time-consuming, labor-intensive, and limited in their ability to capture larger extents of the spatial and temporal dynamics of rangeland ecosystems. Drones provide a solution to collect data to larger extents than field-based methods and with higher-resolution than traditional remote sensing platforms. Our objectives were to (1) assess the accuracy of vegetation cover height in grasses using drones, (2) quantify the spatial distribution of vegetation cover height in grazed and non-grazed pastures during the dormant (fall–winter) and growing seasons (spring–summer), and (3) evaluate the spatial distribution of vegetation cover height as a proxy for northern bobwhite (Colinus virginianus) habitat in South Texas. We achieved this by very fine scale drone-derived imagery and using class level landscape metrics to assess vegetation cover height configuration. Estimated heights from drone imagery had a significant relationship with the field height measurements in September (r2 = 0.83; growing season) and February (r2 = 0.77; dormant season). Growing season pasture maintained residual landscape habitat configuration adequate for bobwhites throughout the fall and winter of 2022–2023 following grazing. Dormant season pasture had an increase in bare ground cover, and a shift from many large patches of tall herbaceous cover (40–120 cm) to few large patches of low herbaceous cover (5–30 cm) (p < 0.05). Drones provided high-resolution imagery that allowed us to assess the spatial and temporal changes of vertical herbaceous vegetation structure in a semi-arid rangeland subject to grazing. This study shows how drone imagery can be beneficial for wildlife conservation and management by providing insights into changes in fine-scale vegetation spatial and temporal heterogeneity from livestock grazing.","PeriodicalId":11419,"journal":{"name":"Ecological Processes","volume":"1 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142219422","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 : 2024-09-03DOI: 10.1186/s13717-024-00545-1
Xiuying Li, Yan Lv, Yuanzhi Wang, Zhipeng Zhang, Jingjing Wang, Huijuan Jin, Tongyue Zhou, Yiru Cui, Yi Yang, Jun Yan
Chlorophenoxy compounds represent a group of selective herbicides widely used around the world. Chlorophenoxy herbicides are toxic, chemically stable, and can migrate into groundwater through soil leaching, posing a significant threat to drinking water safety and human health. Chlorophenoxy herbicides in groundwater aquifers are subject to anaerobic processes; however, the pathway and microbiology involved in the attenuation of chlorophenoxy herbicides under anaerobic condition are largely unknown. Here, the anaerobic degradation process of 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), a typical chlorophenoxy herbicide, was investigated. The initial 52.5 ± 2.3 μM 2,4,5-T was completely degraded by a sediment-derived microbial consortium, with 3,4-dichlorophenol, 2,5-dichlorophenol, 3-chlorophenol (3-CP) and phenol being identified as the intermediate products. Reductive dechlorination of 3-CP to phenol and the subsequent elimination of phenol were the key transformation steps in the overall degradation process of 2,4,5-T. Amplicon sequencing suggested that Dehalobacter, Sulfuricurvum, Bacteroides, Acetobacterium, and Clostridium sensu stricto 7 might contribute to the transformation of 2,4,5-T to phenol, and Smithella, Syntrophorhabdus, Methanofollis and Methanosaeta likely cooperated to accomplish the complete mineralization of phenol. This study reported the anaerobic degradation of 2,4,5-T via reductive dechlorination and the subsequent syntrophic metabolization of phenol, an intermediate product transformed from 2,4,5-T. Dehalobacter was identified as the organohalide-respiring population catalyzing the reductive dechlorination reaction. Syntrophorhabdus and methanogenic populations were likely involved in anaerobic phenol oxidation and facilitated the complete mineralization of 2,4,5-T.
{"title":"Insights into the biodegradation process of 2,4,5-trichlorophenoxyacetic acid under anaerobic condition","authors":"Xiuying Li, Yan Lv, Yuanzhi Wang, Zhipeng Zhang, Jingjing Wang, Huijuan Jin, Tongyue Zhou, Yiru Cui, Yi Yang, Jun Yan","doi":"10.1186/s13717-024-00545-1","DOIUrl":"https://doi.org/10.1186/s13717-024-00545-1","url":null,"abstract":"Chlorophenoxy compounds represent a group of selective herbicides widely used around the world. Chlorophenoxy herbicides are toxic, chemically stable, and can migrate into groundwater through soil leaching, posing a significant threat to drinking water safety and human health. Chlorophenoxy herbicides in groundwater aquifers are subject to anaerobic processes; however, the pathway and microbiology involved in the attenuation of chlorophenoxy herbicides under anaerobic condition are largely unknown. Here, the anaerobic degradation process of 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), a typical chlorophenoxy herbicide, was investigated. The initial 52.5 ± 2.3 μM 2,4,5-T was completely degraded by a sediment-derived microbial consortium, with 3,4-dichlorophenol, 2,5-dichlorophenol, 3-chlorophenol (3-CP) and phenol being identified as the intermediate products. Reductive dechlorination of 3-CP to phenol and the subsequent elimination of phenol were the key transformation steps in the overall degradation process of 2,4,5-T. Amplicon sequencing suggested that Dehalobacter, Sulfuricurvum, Bacteroides, Acetobacterium, and Clostridium sensu stricto 7 might contribute to the transformation of 2,4,5-T to phenol, and Smithella, Syntrophorhabdus, Methanofollis and Methanosaeta likely cooperated to accomplish the complete mineralization of phenol. This study reported the anaerobic degradation of 2,4,5-T via reductive dechlorination and the subsequent syntrophic metabolization of phenol, an intermediate product transformed from 2,4,5-T. Dehalobacter was identified as the organohalide-respiring population catalyzing the reductive dechlorination reaction. Syntrophorhabdus and methanogenic populations were likely involved in anaerobic phenol oxidation and facilitated the complete mineralization of 2,4,5-T.","PeriodicalId":11419,"journal":{"name":"Ecological Processes","volume":"2 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142227437","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 : 2024-08-30DOI: 10.1186/s13717-024-00543-3
Nazim Hassan, Zhengwen Wang
Numerous previous studies have investigated the effects of grazing or mowing on plant community diversity and productivity in grasslands; however, few have deliberately made sound comparison between the effects of paralleled grazing and mowing in terms of biomass removal on plant community diversity and productivity in semi-arid grasslands. Using a 4-year field manipulative experiment, we investigated how moderate intensity of domestic cattle (Bos taurus) grazing and mowing can affect plant community diversity and productivity in the semi-arid grassland in northeastern China, with the attempt to find a better management practice. Our results showed that grazing significantly increased plant species richness by 9% but did not change plant biomass, whereas mowing did not alter plant species richness but significantly reduced total plant biomass and root biomass by 18% and 12%, respectively, and significantly altered plant community composition, reflected by 32% increase of grass to forb biomass ratio. Cattle grazing exerted a neutral effect on plant biomass and a positive effect on plant species richness, suggesting that cattle grazing is a better management practice compared to the paralleled mowing, but longer-term experiments are needed to explore the lasting influences of grazing vs. mowing on grassland productivity, plant diversity and the sustainability.
{"title":"Paralleled grazing and mowing differentially affected plant community diversity and productivity in a semi-arid grassland","authors":"Nazim Hassan, Zhengwen Wang","doi":"10.1186/s13717-024-00543-3","DOIUrl":"https://doi.org/10.1186/s13717-024-00543-3","url":null,"abstract":"Numerous previous studies have investigated the effects of grazing or mowing on plant community diversity and productivity in grasslands; however, few have deliberately made sound comparison between the effects of paralleled grazing and mowing in terms of biomass removal on plant community diversity and productivity in semi-arid grasslands. Using a 4-year field manipulative experiment, we investigated how moderate intensity of domestic cattle (Bos taurus) grazing and mowing can affect plant community diversity and productivity in the semi-arid grassland in northeastern China, with the attempt to find a better management practice. Our results showed that grazing significantly increased plant species richness by 9% but did not change plant biomass, whereas mowing did not alter plant species richness but significantly reduced total plant biomass and root biomass by 18% and 12%, respectively, and significantly altered plant community composition, reflected by 32% increase of grass to forb biomass ratio. Cattle grazing exerted a neutral effect on plant biomass and a positive effect on plant species richness, suggesting that cattle grazing is a better management practice compared to the paralleled mowing, but longer-term experiments are needed to explore the lasting influences of grazing vs. mowing on grassland productivity, plant diversity and the sustainability.","PeriodicalId":11419,"journal":{"name":"Ecological Processes","volume":"7 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142227438","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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