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Shen H, Dong S, DiTommaso A, Westbrook AS, Li S, Zheng H, Zhi Y, Zuo H, Wang Q, Liu J. Physiological factors contribute to increased competitiveness of grass relative to sedge, forb and legume species under different N application levels. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 906:167466. [PMID: 37788779 DOI: 10.1016/j.scitotenv.2023.167466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 09/20/2023] [Accepted: 09/28/2023] [Indexed: 10/05/2023]
Abstract
In alpine grasslands, increased N deposition is increasing the dominance of grasses relative to other functional types according to our previous study Shen et al. (2022). However, the mechanisms that drive this compositional change are not fully understood. We measured the effects of 4-6 years' N addition to simulate N deposition at rates of 0 (CK), 8 (N1), 24 (N2), 40 (N3), 56 (N4), and 72 (N5) kg N ha-1 year-1 on dominant representatives of four functional types, Leymus secalinus (grass), Carex capillifolia (sedge), Potentilla multifidi (non-leguminous forb), and Medicago ruthenica (legume), in the alpine grassland on the Qinghai-Tibetan Plateau (QTP). In-situ experiment showed that N addition increased aboveground biomass in L. secalinus but had negative or neutral effects on aboveground biomass in the other species. Consistent with this finding, N addition increased net photosynthesis, chlorophyll content, and rubisco activity in L. secalinus with less positive effects on the other species. Nitrogen addition increased leaf N content in L. secalinus and C. capillifolia and reduced leaf non-structural carbohydrate content in all four species. In L. secalinus, the highest N addition rate (N5) reduced MDA content, a marker of oxidative stress, by enhancing antioxidant enzyme activity. Overall, our findings suggested that physiological factors can contribute to increased competitiveness of grass relative to sedge, forb and legume species under high N application levels. The rapid growth of this grass species reduces resource availability to non-grass species, increasing its dominance in the alpine meadow.
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Affiliation(s)
- Hao Shen
- School of Grassland Science, Beijing Forestry University, Beijing, 100083, China
| | - Shikui Dong
- School of Grassland Science, Beijing Forestry University, Beijing, 100083, China; School of Environment, State Key Joint Laboratory of Environmental Simulation and Pollution Control, Beijing Normal University, Beijing, 100875, China; Department of Natural Resources, Cornell University, Ithaca, NY 14853, United States.
| | - Antonio DiTommaso
- Soil and Crop Sciences, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853, United States
| | - Anna S Westbrook
- Soil and Crop Sciences, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853, United States
| | - Shuai Li
- College of Resource and Environment, Shanxi Agricultural University, Taigu 030801, China
| | - Hanzhong Zheng
- Department of Environmental Science, Radboud University, 6526 AJ Nijmegen, The Netherlands
| | - Yangliu Zhi
- School of Environment, State Key Joint Laboratory of Environmental Simulation and Pollution Control, Beijing Normal University, Beijing, 100875, China
| | - Hui Zuo
- School of Grassland Science, Beijing Forestry University, Beijing, 100083, China
| | - Qiyun Wang
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng 475004, China
| | - Junxiang Liu
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of the State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing 100091, China
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2
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Schmeller DS, Urbach D, Bates K, Catalan J, Cogălniceanu D, Fisher MC, Friesen J, Füreder L, Gaube V, Haver M, Jacobsen D, Le Roux G, Lin YP, Loyau A, Machate O, Mayer A, Palomo I, Plutzar C, Sentenac H, Sommaruga R, Tiberti R, Ripple WJ. Scientists' warning of threats to mountains. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 853:158611. [PMID: 36087665 DOI: 10.1016/j.scitotenv.2022.158611] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 09/04/2022] [Accepted: 09/04/2022] [Indexed: 06/15/2023]
Abstract
Mountains are an essential component of the global life-support system. They are characterized by a rugged, heterogenous landscape with rapidly changing environmental conditions providing myriad ecological niches over relatively small spatial scales. Although montane species are well adapted to life at extremes, they are highly vulnerable to human derived ecosystem threats. Here we build on the manifesto 'World Scientists' Warning to Humanity', issued by the Alliance of World Scientists, to outline the major threats to mountain ecosystems. We highlight climate change as the greatest threat to mountain ecosystems, which are more impacted than their lowland counterparts. We further discuss the cascade of "knock-on" effects of climate change such as increased UV radiation, altered hydrological cycles, and altered pollution profiles; highlighting the biological and socio-economic consequences. Finally, we present how intensified use of mountains leads to overexploitation and abstraction of water, driving changes in carbon stock, reducing biodiversity, and impacting ecosystem functioning. These perturbations can provide opportunities for invasive species, parasites and pathogens to colonize these fragile habitats, driving further changes and losses of micro- and macro-biodiversity, as well further impacting ecosystem services. Ultimately, imbalances in the normal functioning of mountain ecosystems will lead to changes in vital biological, biochemical, and chemical processes, critically reducing ecosystem health with widespread repercussions for animal and human wellbeing. Developing tools in species/habitat conservation and future restoration is therefore essential if we are to effectively mitigate against the declining health of mountains.
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Affiliation(s)
| | - Davnah Urbach
- Global Mountain Biodiversity Assessment, Institute of Plant Sciences, University of Bern, Bern, Switzerland.
| | - Kieran Bates
- Department of Zoology, University of Oxford, 11a Mansfield Road, Oxford OX1 3SZ, UK; MRC Centre for GlobaI Infectious Disease Analysis, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London W2 1PG, UK; Institute of Zoology, Zoological Society of London, Regent's Park, London NW1 4RY, UK.
| | - Jordi Catalan
- CREAF Campus UAB, Edifici C, Cerdanyola Del Valles, Spain; CSIC, Campus UAB, Cerdanyola Del Valles, Spain.
| | - Dan Cogălniceanu
- Ovidius University Constanţa, Faculty of Natural Sciences and Agricultural Sciences, Al. Universităţii 1, 900470 Constanţa, Romania
| | - Matthew C Fisher
- MRC Centre for GlobaI Infectious Disease Analysis, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London W2 1PG, UK.
| | - Jan Friesen
- Helmholtz Centre for Environmental Research - UFZ, Leipzig, Germany.
| | - Leopold Füreder
- Department of Ecology, University of Innsbruck, Technikerstr. 25, 6020 Innsbruck, Austria.
| | - Veronika Gaube
- University of Natural Resources and Life Sciences, Vienna, Department of Economics and Social Sciences, Institute of Social Ecology (SEC), Schottenfeldgasse 29, Austria.
| | - Marilen Haver
- LEFE, Université de Toulouse, INPT, UPS, Toulouse, France.
| | - Dean Jacobsen
- Freshwater Biological Section, Dept. Biology, University of Copenhagen, Denmark.
| | - Gael Le Roux
- LEFE, Université de Toulouse, INPT, UPS, Toulouse, France.
| | - Yu-Pin Lin
- Department of Bioenvironmental Systems Engineering, National Taiwan University, Taiwan.
| | - Adeline Loyau
- LEFE, Université de Toulouse, INPT, UPS, Toulouse, France.
| | - Oliver Machate
- Helmholtz Centre for Environmental Research - UFZ, Leipzig, Germany
| | - Andreas Mayer
- University of Natural Resources and Life Sciences, Vienna, Department of Economics and Social Sciences, Institute of Social Ecology (SEC), Schottenfeldgasse 29, Austria.
| | - Ignacio Palomo
- Univ. Grenoble-Alpes, IRD, CNRS, Grenoble INP*, IGE, 38000 Grenoble, France.
| | - Christoph Plutzar
- University of Natural Resources and Life Sciences, Vienna, Department of Economics and Social Sciences, Institute of Social Ecology (SEC), Schottenfeldgasse 29, Austria.
| | - Hugo Sentenac
- LEFE, Université de Toulouse, INPT, UPS, Toulouse, France.
| | - Ruben Sommaruga
- Department of Ecology, University of Innsbruck, Technikerstr. 25, 6020 Innsbruck, Austria.
| | - Rocco Tiberti
- Department of Earth and Environmental Sciences - DSTA, University of Pavia, Via Ferrata 9, 27100 Pavia, Italy.
| | - William J Ripple
- Department of Forest Ecosystems and Society, Oregon State University, Corvallis, OR, USA.
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3
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Shen H, Dong S, DiTommaso A, Xiao J, Lu W, Zhi Y. Nitrogen Deposition Shifts Grassland Communities Through Directly Increasing Dominance of Graminoids: A 3-Year Case Study From the Qinghai-Tibetan Plateau. FRONTIERS IN PLANT SCIENCE 2022; 13:811970. [PMID: 35317015 PMCID: PMC8934429 DOI: 10.3389/fpls.2022.811970] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Accepted: 01/18/2022] [Indexed: 05/25/2023]
Abstract
Nitrogen (N) deposition has been increasing for decades and has profoundly influenced the structure and function of grassland ecosystems in many regions of the world. However, the impact of N deposition on alpine grasslands is less well documented. We conducted a 3-year field experiment to determine the effects of N deposition on plant species richness, composition, and community productivity in an alpine meadow of the Qinghai-Tibetan Plateau of China. We found that 3 years of N deposition had a profound effect on these plant community parameters. Increasing N rates increased the dominance of graminoids and reduced the presence of non-graminoids. Species richness was inversely associated with aboveground biomass. The shift in plant species and functional group composition was largely responsible for the increase in productivity associated with N deposition. Climatic factors also interacted with N addition to influence productivity. Our findings suggest that short-term N deposition could increase the productivity of alpine meadows through shifts in composition toward a graminoid-dominated community. Longer-term studies are needed to determine if shifts in composition and increased productivity will be maintained. Future work must also evaluate whether decreasing plant diversity will impair the long-term stability and function of sensitive alpine grasslands.
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Affiliation(s)
- Hao Shen
- School of Grassland Science, Beijing Forestry University, Beijing, China
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Beijing Normal University, Beijing, China
- Soil and Crop Sciences, School of Integrative Plant Science, Cornell University, Ithaca, NY, United States
| | - Shikui Dong
- School of Grassland Science, Beijing Forestry University, Beijing, China
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Beijing Normal University, Beijing, China
- Department of Natural Resources, Cornell University, Ithaca, NY, United States
| | - Antonio DiTommaso
- Soil and Crop Sciences, School of Integrative Plant Science, Cornell University, Ithaca, NY, United States
| | - Jiannan Xiao
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Beijing Normal University, Beijing, China
| | - Wen Lu
- Ministry of Education Key Laboratory of Ecology and Resource Use of the Mongolia Plateau, Collaborative Innovation Center for Grassland Ecological Security, College of Ecology and Environment, Inner Mongolia University, Hohhot, China
| | - Yangliu Zhi
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Beijing Normal University, Beijing, China
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4
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Pollack IB, McCabe ME, Caulton DR, Fischer EV. Enhancements in Ammonia and Methane from Agricultural Sources in the Northeastern Colorado Front Range Using Observations from a Small Research Aircraft. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:2236-2247. [PMID: 35076215 DOI: 10.1021/acs.est.1c07382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Quantifying ammonia (NH3) to methane (CH4) enhancement ratios from agricultural sources is important for understanding air pollution and nitrogen deposition. The northeastern Colorado Front Range is home to concentrated animal feeding operations (CAFOs) that produce large emissions of NH3 and CH4. Isolating enhancements of NH3 and CH4 in this region due to agriculture is complicated because CAFOs are often located within regions of oil and natural gas (O&NG) extraction that are a major source of CH4 and other alkanes. Here, we utilize a small research aircraft to collect in situ 1 Hz measurements of gas-phase NH3, CH4, and ethane (C2H6) downwind of CAFOs during three flights conducted in November 2019. Enhancements in NH3 and CH4 are distinguishable up to 10 km downwind of CAFOs with the most concentrated portions of the plumes typically below 0.25 km AGL. We demonstrate that NH3 and C2H6 can be jointly used to separate near-source enhancements in CH4 from agriculture and O&NG. Molar enhancement ratios of NH3 to CH4 are quantified for individual CAFOs in this region, and they range from 0.8 to 2.7 ppbv ppbv-1. A multivariate regression model produces enhancement ratios and quantitative regional source contributions that are consistent with prior studies.
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Affiliation(s)
- Ilana B Pollack
- Department of Atmospheric Science, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Megan E McCabe
- Department of Atmospheric Science, University of Wyoming, Laramie, Wyoming 82071, United States
| | - Dana R Caulton
- Department of Atmospheric Science, University of Wyoming, Laramie, Wyoming 82071, United States
| | - Emily V Fischer
- Department of Atmospheric Science, Colorado State University, Fort Collins, Colorado 80523, United States
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5
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Lu P, Hao T, Li X, Wang H, Zhai X, Tian Q, Bai W, Stevens C, Zhang W. Ambient nitrogen deposition drives plant‐diversity decline by nitrogen accumulation in a closed grassland ecosystem. J Appl Ecol 2021. [DOI: 10.1111/1365-2664.13858] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Peng Lu
- State Key Laboratory of Vegetation and Environmental Change Institute of Botany Chinese Academy of Sciences Beijing China
| | - Tianxiang Hao
- College of Resources and Environmental Sciences Key Laboratory of Plant–Soil Interactions of the Ministry of Education China Agricultural University Beijing China
| | - Xin Li
- State Key Laboratory of Vegetation and Environmental Change Institute of Botany Chinese Academy of Sciences Beijing China
- College of Resource and Environment University of Chinese Academy of Sciences Beijing China
| | - Hong Wang
- Mountain Area Research Institute Agricultural University of Hebei Baoding China
| | - Xiufeng Zhai
- State Key Laboratory of Vegetation and Environmental Change Institute of Botany Chinese Academy of Sciences Beijing China
- College of Resource and Environment University of Chinese Academy of Sciences Beijing China
| | - Qiuying Tian
- State Key Laboratory of Vegetation and Environmental Change Institute of Botany Chinese Academy of Sciences Beijing China
| | - Wenming Bai
- State Key Laboratory of Vegetation and Environmental Change Institute of Botany Chinese Academy of Sciences Beijing China
| | - Carly Stevens
- Lancaster Environment Centre Lancaster University Lancaster UK
| | - Wen‐Hao Zhang
- State Key Laboratory of Vegetation and Environmental Change Institute of Botany Chinese Academy of Sciences Beijing China
- College of Resource and Environment University of Chinese Academy of Sciences Beijing China
- Inner Mongolia Research Center for Prataculture Chinese Academy of Sciences Beijing China
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6
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Pan D, Benedict KB, Golston LM, Wang R, Collett JL, Tao L, Sun K, Guo X, Ham J, Prenni AJ, Schichtel BA, Mikoviny T, Müller M, Wisthaler A, Zondlo MA. Ammonia Dry Deposition in an Alpine Ecosystem Traced to Agricultural Emission Hotpots. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:7776-7785. [PMID: 34061518 DOI: 10.1021/acs.est.0c05749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Elevated reactive nitrogen (Nr) deposition is a concern for alpine ecosystems, and dry NH3 deposition is a key contributor. Understanding how emission hotspots impact downwind ecosystems through dry NH3 deposition provides opportunities for effective mitigation. However, direct NH3 flux measurements with sufficient temporal resolution to quantify such events are rare. Here, we measured NH3 fluxes at Rocky Mountain National Park (RMNP) during two summers and analyzed transport events from upwind agricultural and urban sources in northeastern Colorado. We deployed open-path NH3 sensors on a mobile laboratory and an eddy covariance tower to measure NH3 concentrations and fluxes. Our spatial sampling illustrated an upslope event that transported NH3 emissions from the hotspot to RMNP. Observed NH3 deposition was significantly higher when backtrajectories passed through only the agricultural region (7.9 ng m-2 s-1) versus only the urban area (1.0 ng m-2 s-1) and both urban and agricultural areas (2.7 ng m-2 s-1). Cumulative NH3 fluxes were calculated using observed, bidirectional modeled, and gap-filled fluxes. More than 40% of the total dry NH3 deposition occurred when air masses were traced back to agricultural source regions. More generally, we identified that 10 (25) more national parks in the U.S. are within 100 (200) km of an NH3 hotspot, and more observations are needed to quantify the impacts of these hotspots on dry NH3 deposition in these regions.
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Affiliation(s)
- Da Pan
- Department of Civil and Environmental Engineering, Princeton University, Princeton 08544, New Jersey, United States
- Center for Mid-Infrared Technologies for Health and the Environmental, NSF-ERC, Princeton, New Jersey 08540, United States
| | - Katherine B Benedict
- Department of Atmospheric Science, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Levi M Golston
- Department of Civil and Environmental Engineering, Princeton University, Princeton 08544, New Jersey, United States
- Center for Mid-Infrared Technologies for Health and the Environmental, NSF-ERC, Princeton, New Jersey 08540, United States
| | - Rui Wang
- Department of Civil and Environmental Engineering, Princeton University, Princeton 08544, New Jersey, United States
- Center for Mid-Infrared Technologies for Health and the Environmental, NSF-ERC, Princeton, New Jersey 08540, United States
| | - Jeffrey L Collett
- Department of Atmospheric Science, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Lei Tao
- Department of Civil and Environmental Engineering, Princeton University, Princeton 08544, New Jersey, United States
- Center for Mid-Infrared Technologies for Health and the Environmental, NSF-ERC, Princeton, New Jersey 08540, United States
| | - Kang Sun
- Department of Civil, Structural and Environmental Engineering, University at Buffalo, Buffalo, New York 14260, United States
- Research and Education in Energy, Environment and Water (RENEW) Institute, University at Buffalo, Buffalo, New York 14260, United States
| | - Xuehui Guo
- Department of Civil and Environmental Engineering, Princeton University, Princeton 08544, New Jersey, United States
- Center for Mid-Infrared Technologies for Health and the Environmental, NSF-ERC, Princeton, New Jersey 08540, United States
| | - Jay Ham
- Department of Soil and Crop Sciences, Colorado State University, Fort Collins, Colorado 80521, United States
| | - Anthony J Prenni
- Air Resources Division, National Park Service, Lakewood, Colorado 80235, United States
| | - Bret A Schichtel
- Air Resources Division, National Park Service, Fort Collins, Colorado 80525, United States
| | - Tomas Mikoviny
- Chemistry and Dynamics Branch, Science Directorate, NASA Langley Research Center, Hampton, Virginia 23666, United States
- Oak Ridge Associated Universities, Oak Ridge, Tennessee 37830, United States
- Department of Chemistry, University of Oslo, Oslo 0315, Norway
| | - Markus Müller
- Institute for Ion Physics and Applied Physics, University of Innsbruck, Innsbruck 6020, Austria
| | - Armin Wisthaler
- Department of Chemistry, University of Oslo, Oslo 0315, Norway
- Institute for Ion Physics and Applied Physics, University of Innsbruck, Innsbruck 6020, Austria
| | - Mark A Zondlo
- Department of Civil and Environmental Engineering, Princeton University, Princeton 08544, New Jersey, United States
- Center for Mid-Infrared Technologies for Health and the Environmental, NSF-ERC, Princeton, New Jersey 08540, United States
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7
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Climate Change, Ecosystem Processes and Biological Diversity Responses in High Elevation Communities. CLIMATE 2021. [DOI: 10.3390/cli9050087] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The populations, species, and communities in high elevation mountainous regions at or above tree line are being impacted by the changing climate. Mountain systems have been recognized as both resilient and extremely threatened by climate change, requiring a more nuanced understanding of potential trajectories of the biotic communities. For high elevation systems in particular, we need to consider how the interactions among climate drivers and topography currently structure the diversity, species composition, and life-history strategies of these communities. Further, predicting biotic responses to changing climate requires knowledge of intra- and inter-specific climate associations within the context of topographically heterogenous landscapes. Changes in temperature, snow, and rain characteristics at regional scales are amplified or attenuated by slope, aspect, and wind patterns occurring at local scales that are often under a hectare or even a meter in extent. Community assemblages are structured by the soil moisture and growing season duration at these local sites, and directional climate change has the potential to alter these two drivers together, independently, or in opposition to one another due to local, intervening variables. Changes threaten species whose water and growing season duration requirements are locally extirpated or species who may be outcompeted by nearby faster-growing, warmer/drier adapted species. However, barring non-analogue climate conditions, species may also be able to more easily track required resource regimes in topographically heterogenous landscapes. New species arrivals composed of competitors, predators and pathogens can further mediate the direct impacts of the changing climate. Plants are moving uphill, demonstrating primary succession with the emergence of new habitats from snow and rock, but these shifts are constrained over the short term by soil limitations and microbes and ultimately by the lack of colonizable terrestrial surfaces. Meanwhile, both subalpine herbaceous and woody species pose threats to more cold-adapted species. Overall, the multiple interacting direct and indirect effects of the changing climate on high elevation systems may lead to multiple potential trajectories for these systems.
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8
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Wilcots ME, Harpole WS, Seabloom EW, Borer ET. Community change can buffer chronic nitrogen impacts, but multiple nutrients tip the scale. Ecology 2021; 102:e03355. [PMID: 33797757 DOI: 10.1002/ecy.3355] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 12/22/2020] [Accepted: 02/05/2021] [Indexed: 11/08/2022]
Abstract
Anthropogenic nitrogen (N) inputs are causing large changes in ecosystems worldwide. Many previous studies have examined the impact of N on terrestrial ecosystems; however, most have added N at rates that are much higher than predicted future deposition rates. Here, we present the results from a gradient of experimental N addition (0-10 g·N·m-2 ) in a temperate grassland. After a decade of N addition, we found that all levels of N addition changed plant functional group composition, likely indicating altered function for plant communities exposed to 10 yr of N inputs. However, N addition only had weak impacts on species composition and this functional group shift was not driven by any particular species, suggesting high levels of functional redundancy among grasslands species. Adding other nutrients (P, K, and micronutrients) in combination with N caused substantially greater changes in the relative abundance of species and functional groups. Together, these results suggest that compositional change within functional groups may buffer grasslands from impacts of N deposition, but concurrent eutrophication with other elements will likely lead to substantial changes in plant composition and biomass.
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Affiliation(s)
- Megan E Wilcots
- Department of Ecology, Evolution, and Behavior, University of Minnesota, 1987 Upper Buford Circle, St. Paul, Minnesota, 55108, USA
| | - W Stanley Harpole
- Department of Physiological Diversity, Helmholtz Center for Environmental Research - UFZ, Permoserstrasse 15, Leipzig, 04318, Germany.,German Centre for Integrative Biodiversity Research (iDiv), Puschstrasse 4, Leipzig, 04103, Germany.,Martin Luther University Halle-Wittenberg, am Kirchtor 1, Halle (Saale), 06108, Germany
| | - Eric W Seabloom
- Department of Ecology, Evolution, and Behavior, University of Minnesota, 1987 Upper Buford Circle, St. Paul, Minnesota, 55108, USA
| | - Elizabeth T Borer
- Department of Ecology, Evolution, and Behavior, University of Minnesota, 1987 Upper Buford Circle, St. Paul, Minnesota, 55108, USA
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9
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Chen Q, Yuan Y, Hu Y, Wang J, Si G, Xu R, Zhou J, Xi C, Hu A, Zhang G. Excessive nitrogen addition accelerates N assimilation and P utilization by enhancing organic carbon decomposition in a Tibetan alpine steppe. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 764:142848. [PMID: 33268263 DOI: 10.1016/j.scitotenv.2020.142848] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Revised: 09/23/2020] [Accepted: 10/03/2020] [Indexed: 05/23/2023]
Abstract
High amounts of deposited nitrogen (N) dramatically influence the stability and functions of alpine ecosystems by changing soil microbial community functions, but the mechanism is still unclear. To investigate the impacts of increased N deposition on microbial community functions, a 2-year multilevel N addition (0, 10, 20, 40, 80 and 160 kg N ha-1 year-1) field experiment was set up in an alpine steppe on the Tibetan Plateau. Soil microbial functional genes (GeoChip 4.6), together with soil enzyme activity, soil organic compounds and environmental variables, were used to explore the response of microbial community functions to N additions. The results showed that the N addition rate of 40 kg N ha-1 year-1 was the critical value for soil microbial functional genes in this alpine steppe. A small amount of added N (≤40 kg N ha-1 year-1) had no significant effects on the abundance of microbial functional genes, while high amounts of added N (>40 kg N ha-1 year-1) significantly increased the abundance of soil organic carbon degradation genes. Additionally, the abundance of microbial functional genes associated with NH4+, including ammonification, N fixation and assimilatory nitrate reduction pathways, was significantly increased under high N additions. Further, high N additions also increased soil organic phosphorus utilization, which was indicated by the increase in the abundance of phytase genes and alkaline phosphatase activity. Plant richness, soil NO2-/NH4+ and WSOC/WSON were significantly correlated with the abundance of microbial functional genes, which drove the changes in microbial community functions under N additions. These findings help us to predict that increased N deposition in the future may alter soil microbial functional structure, which will lead to changes in microbially-mediated biogeochemical dynamics in alpine steppes on the Tibetan Plateau and will have extraordinary impacts on microbial C, N and P cycles.
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Affiliation(s)
- Qiuyu Chen
- CAS Key Laboratory of Alpine Ecology, Institute of Tibetan Plateau Research, Chinese Academy of Sciences (CAS), Beijing 100101, China
| | - Yanli Yuan
- CAS Key Laboratory of Alpine Ecology, Institute of Tibetan Plateau Research, Chinese Academy of Sciences (CAS), Beijing 100101, China
| | - Yilun Hu
- CAS Key Laboratory of Alpine Ecology, Institute of Tibetan Plateau Research, Chinese Academy of Sciences (CAS), Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100101, China
| | - Jian Wang
- Land and Resources College, China West Normal University, Nanchong 637009, Sichuan, China
| | - Guicai Si
- Lanzhou Center for Oil and Gas Resources, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China
| | - Ri Xu
- CAS Key Laboratory of Alpine Ecology, Institute of Tibetan Plateau Research, Chinese Academy of Sciences (CAS), Beijing 100101, China
| | - Jizhong Zhou
- Institute for Environmental Genomics and Department of Microbiology and Plant Biology, University Oklahoma, Norman, OK 73019, USA; State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Chuanwu Xi
- Department of Environmental Health Sciences, School of Public Health, University of Michigan, Ann Arbor, MI 48109, USA
| | - Ang Hu
- College of Resources and Environment, Hunan Agricultural University, Changsha 410128, China
| | - Gengxin Zhang
- CAS Key Laboratory of Alpine Ecology, Institute of Tibetan Plateau Research, Chinese Academy of Sciences (CAS), Beijing 100101, China; CAS Center for Excellence in Tibetan Plateau Earth Sciences, Chinese Academy of Sciences, Beijing 100101, China.
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10
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Walker JT, Bell MD, Schwede D, Cole A, Beachley G, Lear G, Wu Z. Aspects of uncertainty in total reactive nitrogen deposition estimates for North American critical load applications. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 690:1005-1018. [PMID: 31302534 PMCID: PMC7724635 DOI: 10.1016/j.scitotenv.2019.06.337] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 06/20/2019] [Accepted: 06/21/2019] [Indexed: 06/07/2023]
Abstract
Determination of the amount of reactive nitrogen (Nr) deposition in excess of the ecosystem critical load (CL) requires an estimate of total deposition. Because the CL exceedance is used to inform policy decisions, uncertainty in both the CL and the exceedance itself must be understood. In this paper we review the state of the science with respect to the sources of uncertainty in total Nr deposition budgets used for CL assessments in North America and put forth recommendations for research and monitoring to improve deposition measurements and models. In the absence of methods to rigorously quantify uncertainty in total Nr deposition, a simple weighted deposition uncertainty metric (WDUM) is introduced as a tool for scientists and decision makers to use in assessing CL exceedances. Maps of the WDUM applied to National Atmospheric Deposition Program (NADP) Total Deposition (TDep) estimates show greater uncertainty in areas of the U.S. where dry deposition makes a larger contribution to the deposition budget, particularly ammonia (NH3) in agricultural areas and oxidized nitrogen (NOx) in urban areas. Organic N deposition is an important source of uncertainty over much of the U.S. Our analysis illustrates how the WDUM can be used to assess spatial patterns of deposition uncertainty and inform actions to improve deposition budgets for CL assessments at the local scale.
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Affiliation(s)
- John T Walker
- U.S. EPA, Office of Research and Development, Durham, NC, United States of America.
| | - Michael D Bell
- National Park Service, Air Resources Division, Lakewood, CO, United States of America
| | - Donna Schwede
- U.S. EPA, Office of Research and Development, Durham, NC, United States of America
| | - Amanda Cole
- Environment and Climate Change Canada, Air Quality Research Division, Toronto, ON, Canada
| | - Greg Beachley
- U.S. EPA, Office of Air Programs, Washington, DC, United States of America
| | - Gary Lear
- U.S. EPA, Office of Air Programs, Washington, DC, United States of America
| | - Zhiyong Wu
- U.S. EPA, Office of Research and Development, Durham, NC, United States of America
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Piña AJ, Schumacher RS, Denning AS, Faulkner WB, Baron JS, Ham J, Ojima DS, Collett JL. Reducing Wet Ammonium Deposition in Rocky Mountain National Park: the Development and Evaluation of A Pilot Early Warning System for Agricultural Operations in Eastern Colorado. ENVIRONMENTAL MANAGEMENT 2019; 64:626-639. [PMID: 31583444 DOI: 10.1007/s00267-019-01209-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Accepted: 09/05/2019] [Indexed: 06/10/2023]
Abstract
Agricultural emissions are the primary source of ammonia (NH3) deposition in Rocky Mountain National Park (RMNP), a Class I area, that is granted special air quality protections under the Clean Air Act. Between 2014 and 2016, the pilot phase of the Colorado agricultural nitrogen early warning system (CANEWS) was developed for agricultural producers to voluntarily and temporarily minimize emissions of NH3 during periods of upslope winds. The CANEWS was created using trajectory analyses driven by outputs from an ensemble of numerical weather forecasts together with the climatological expertize of human forecasters. Here, we discuss the methods for the CANEWS and offer preliminary analyses of 33 months of the CANEWS based on atmospheric deposition data from two sites in RMNP as well as responses from agricultural producers after warnings were issued. Results showed that the CANEWS accurately predicted 6 of 9 high N deposition weeks at a lower-elevation observation site, but only 4 of 11 high N deposition weeks at a higher-elevation site. Sixty agricultural producers from 39 of Colorado's agricultural operations volunteered for the CANEWS, and a two-way line of communication between agricultural producers and scientists was formed. For each warning issued, an average of 23 producers responded to a postwarning survey. Over 75% of responding CANEWS participants altered their practices after an alert. While the current effort was insufficient to reduce atmospheric deposition, we were encouraged by the collaborative spirit between agricultural, scientific, and resource management communities. Solving a broad and complex social-ecological problem requires both a technological approach, such as the CANEWS, and collaboration and trust from all participants, including agricultural producers, land managers, university researchers, and environmental agencies.
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Affiliation(s)
- Aaron J Piña
- Earth Science Division, NASA Headquarters, Washington, DC, USA.
| | - Russ S Schumacher
- Department of Atmospheric Science, Colorado State University, Fort Collins, CO, USA
| | - A Scott Denning
- Department of Atmospheric Science, Colorado State University, Fort Collins, CO, USA
| | - William B Faulkner
- Department of Biological and Agricultural Engineering, Texas A&M University, College Station, TX, USA
| | - Jill S Baron
- US Geological Survey, Fort Collins Science Center, Fort Collins, CO, USA
| | - Jay Ham
- Department of Soil & Crop Sciences, Colorado State University, Fort Collins, CO, USA
| | - Dennis S Ojima
- Department of Ecosystem Science and Sustainability, Colorado State University, Fort Collins, CO, USA
| | - Jeffrey L Collett
- Department of Atmospheric Science, Colorado State University, Fort Collins, CO, USA
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Zong N, Zhao G, Shi P. Different sensitivity and threshold in response to nitrogen addition in four alpine grasslands along a precipitation transect on the Northern Tibetan Plateau. Ecol Evol 2019; 9:9782-9793. [PMID: 31534693 PMCID: PMC6745826 DOI: 10.1002/ece3.5514] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 07/10/2019] [Accepted: 07/10/2019] [Indexed: 11/29/2022] Open
Abstract
The increase in atmospheric nitrogen (N) deposition has resulted in some terrestrial ecological changes. In order to identify the response of sensitive indicators to N input and estimate the sensitivity and saturation thresholds in alpine grasslands, we set up a series of multilevel N addition experiments in four types of alpine grasslands (alpine meadow [AM], alpine meadow-steppe [AMS], alpine steppe [AS], and alpine desert-steppe [ADS]) along with a decreasing precipitation gradient from east to west on the Northern Tibetan Plateau. N addition only had significant effects on species diversity in AMS, while had no effects on the other three alpine grasslands. Aboveground biomass of grasses and overall community in ADS were enhanced with increasing N addition, but such effects did not occur in AS. Legume biomass in ADS and AS showed similar unimodal patterns and exhibited a decreasing tend in AM. Regression fitting showed that the most sensitive functional groups were grasses, and the N saturation thresholds were 103, 115, 136, and 156 kg N hm-2 year-1 in AM, AMS, AS, and ADS, respectively. This suggests that alpine grasslands become more and more insensitive to N input with precipitation decrease. N saturation thresholds also negatively correlated with soil N availability. N sensitivity differences caused by precipitation and nutrient availability suggest that alpine grasslands along the precipitation gradient will respond differently to atmospheric N deposition in the future global change scenario. This different sensitivity should also be taken into consideration when using N fertilization to restore degraded grasslands.
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Affiliation(s)
- Ning Zong
- Lhasa National Ecological Research Station, Key Laboratory of Ecosystem Network Observation and Modelling, Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijingChina
| | - Guangshuai Zhao
- Lhasa National Ecological Research Station, Key Laboratory of Ecosystem Network Observation and Modelling, Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijingChina
- China National Forestry Economics and Development Research CenterBeijingChina
| | - Peili Shi
- Lhasa National Ecological Research Station, Key Laboratory of Ecosystem Network Observation and Modelling, Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijingChina
- University of Chinese Academy of SciencesBeijingChina
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13
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Symstad AJ, Smith AT, Newton WE, Knapp AK. Experimentally derived nitrogen critical loads for northern Great Plains vegetation. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2019; 29:e01915. [PMID: 31056839 DOI: 10.1002/eap.1915] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 03/07/2019] [Accepted: 04/16/2019] [Indexed: 06/09/2023]
Abstract
The critical load concept facilitates communication between scientists and policy makers and land managers by translating the complex effects of air pollution on ecosystems into unambiguous numbers that can be used to inform air quality targets. Anthropogenic atmospheric nitrogen (N) deposition adversely affects a variety of ecosystems, but the information used to derive critical loads for North American ecosystems is sparse and often based on experiments investigating N loads substantially higher than current or expected atmospheric deposition. In a 4-yr field experiment in the northern Great Plains (NGP) of North America, where current N deposition levels range from ~3 to 9 kg N·ha-1 ·yr-1 , we added 12 levels of N, from 2.5 to 100 kg N·ha-1 ·yr-1 , to three sites spanning a range of soil fertility and productivity. Our results suggest a conservative critical load of 4-6 kg N·ha-1 ·yr-1 for the most sensitive vegetation type we investigated, badlands sparse vegetation, a community that supports plant species adapted to low fertility conditions, where N addition at this rate increased productivity and litter load. In contrast, for the two more productive vegetation types characteristic of most NGP grasslands, a critical load of 6-10 kg N·ha-1 ·yr-1 was identified. Here, N addition at this level altered plant tissue chemistry and increased nonnative species. These critical loads are below the currently suggested range of 10-25 kg N·ha-1 ·yr-1 for NGP vegetation and within the range of current or near-future deposition, suggesting that N deposition may already be inducing fundamental changes in NGP ecosystems.
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Affiliation(s)
- Amy J Symstad
- U.S. Geological Survey, Northern Prairie Wildlife Research Center, 26611 U.S. Highway 385, Hot Springs, South Dakota, 57747, USA
| | - Anine T Smith
- Department of Biology and Graduate Degree Program in Ecology, Colorado State University, Fort Collins, Colorado, 80523, USA
| | - Wesley E Newton
- U.S. Geological Survey, Northern Prairie Wildlife Research Center, Jamestown, North Dakota, 58401, USA
| | - Alan K Knapp
- Department of Biology and Graduate Degree Program in Ecology, Colorado State University, Fort Collins, Colorado, 80523, USA
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Wilkening JL, Cole EJ, Beever EA. Evaluating mechanisms of plant‐mediated effects on herbivore persistence and occupancy across an ecoregion. Ecosphere 2019. [DOI: 10.1002/ecs2.2764] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Affiliation(s)
- Jennifer L. Wilkening
- Southern Nevada Fish and Wildlife Office U. S. Fish and Wildlife Service 4701 N. Torrey Pines Drive Las Vegas Nevada 89130 USA
| | - Evan J. Cole
- Department of Environmental Science University of San Francisco 1843A Powell Street San Francisco California 94133 USA
| | - Erik A. Beever
- Northern Rocky Mountain Science Center U.S. Geological Survey 2327 University Avenue, Suite 2 Bozeman Montana 59715 USA
- Department of Ecology Montana State University Bozeman Montana 59717 USA
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15
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Peng Y, Wang G, Li F, Yang G, Fang K, Liu L, Qin S, Zhang D, Zhou G, Fang H, Liu X, Liu C, Yang Y. Unimodal Response of Soil Methane Consumption to Increasing Nitrogen Additions. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:4150-4160. [PMID: 30892031 DOI: 10.1021/acs.est.8b04561] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Nitrogen (N) status has a great impact on methane (CH4) consumption by soils. Modeling studies predicting soil CH4 consumption assume a linear relationship between CH4 uptake and N addition rate. Here, we present evidence that a nonlinear relationship may better characterize changes in soil CH4 uptake with increasing N additions. By conducting a field experiment with eight N-input levels in a Tibetan alpine steppe, we observed a unimodal relationship; CH4 uptake increased at low to medium N levels but declined at high N levels. Environmental and microbial properties jointly determined this response pattern. The generality of the unimodal trend was further validated by two independent analyses: (i) we examined soil CH4 uptake across at least five N-input levels in upland ecosystems across China. A unimodal CH4 uptake-N addition rate relationship was observed in 3 out of 4 cases; and (ii) we performed a meta-analysis to explore the N-induced changes in soil CH4 uptake with increasing N additions across global upland ecosystems. Results showed that the changes in CH4 uptake exhibited a quadratic correlation with N addition rate. Overall, we suggest that the unimodal relationship should be considered in biogeochemistry models for accurately predicting soil CH4 consumption under global N enrichment.
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Affiliation(s)
- Yunfeng Peng
- State Key Laboratory of Vegetation and Environmental Change , Institute of Botany, Chinese Academy of Sciences , Beijing 100093 , P. R. China
| | - Guanqin Wang
- State Key Laboratory of Vegetation and Environmental Change , Institute of Botany, Chinese Academy of Sciences , Beijing 100093 , P. R. China
- University of Chinese Academy of Sciences , Beijing 100049 , P. R. China
| | - Fei Li
- State Key Laboratory of Vegetation and Environmental Change , Institute of Botany, Chinese Academy of Sciences , Beijing 100093 , P. R. China
- University of Chinese Academy of Sciences , Beijing 100049 , P. R. China
| | - Guibiao Yang
- State Key Laboratory of Vegetation and Environmental Change , Institute of Botany, Chinese Academy of Sciences , Beijing 100093 , P. R. China
- University of Chinese Academy of Sciences , Beijing 100049 , P. R. China
| | - Kai Fang
- State Key Laboratory of Vegetation and Environmental Change , Institute of Botany, Chinese Academy of Sciences , Beijing 100093 , P. R. China
- University of Chinese Academy of Sciences , Beijing 100049 , P. R. China
| | - Li Liu
- State Key Laboratory of Vegetation and Environmental Change , Institute of Botany, Chinese Academy of Sciences , Beijing 100093 , P. R. China
- University of Chinese Academy of Sciences , Beijing 100049 , P. R. China
| | - Shuqi Qin
- State Key Laboratory of Vegetation and Environmental Change , Institute of Botany, Chinese Academy of Sciences , Beijing 100093 , P. R. China
- University of Chinese Academy of Sciences , Beijing 100049 , P. R. China
| | - Dianye Zhang
- State Key Laboratory of Vegetation and Environmental Change , Institute of Botany, Chinese Academy of Sciences , Beijing 100093 , P. R. China
- University of Chinese Academy of Sciences , Beijing 100049 , P. R. China
| | - Guoying Zhou
- Northwest Institute of Plateau Biology , Chinese Academy of Sciences , Xining 810008 , P. R. China
- Key Laboratory of Tibetan Medicine Research , Chinese Academy of Sciences , Xining 810008 , P. R. China
| | - Huajun Fang
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research , Chinese Academy of Sciences , Beijing 100101 , P. R. China
| | - Xuejun Liu
- College of Resources and Environmental Sciences , China Agricultural University , Beijing 100193 , P. R. China
| | - Chunyan Liu
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics , Chinese Academy of Sciences , Beijing 100029 , P. R. China
| | - Yuanhe Yang
- State Key Laboratory of Vegetation and Environmental Change , Institute of Botany, Chinese Academy of Sciences , Beijing 100093 , P. R. China
- University of Chinese Academy of Sciences , Beijing 100049 , P. R. China
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16
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Wentz KF, Neff JC, Suding KN. Leaf temperatures mediate alpine plant communities' response to a simulated extended summer. Ecol Evol 2019; 9:1227-1243. [PMID: 30805155 PMCID: PMC6374730 DOI: 10.1002/ece3.4816] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 09/26/2018] [Accepted: 11/20/2018] [Indexed: 11/10/2022] Open
Abstract
We use a quantitative model of photosynthesis to explore leaf-level limitations to plant growth in an alpine tundra ecosystem that is expected to have longer, warmer, and drier growing seasons. The model is parameterized with abiotic and leaf trait data that is characteristic of two dominant plant communities in the alpine tundra and specifically at the Niwot Ridge Long Term Ecological Research Site: the dry and wet meadows. Model results produce realistic estimates of photosynthesis, nitrogen-use efficiency, water-use efficiency, and other gas exchange processes in the alpine tundra. Model simulations suggest that dry and wet meadow plant species do not significantly respond to changes in the volumetric soil moisture content but are sensitive to variation in foliar nitrogen content. In addition, model simulations indicate that dry and wet meadow species have different maximum rates of assimilation (normalized for leaf nitrogen content) because of differences in leaf temperature. These differences arise from the interaction of plant height and the abiotic environment characteristic of each plant community. The leaf temperature of dry meadow species is higher than wet meadow species and close to the optimal temperature for photosynthesis under current conditions. As a result, 2°C higher air temperatures in the future will likely lead to declines in dry meadow species' carbon assimilation. On the other hand, a longer and warmer growing season could increase nitrogen availability and assimilation rates in both plant communities. Nonetheless, a temperature increase of 4°C may lower rates of assimilation in both dry and wet meadow plant communities because of higher, and suboptimal, leaf temperatures.
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Affiliation(s)
| | - Jason C. Neff
- Environmental Studies DepartmentUniversity of ColoradoBoulderColorado
| | - Katharine N. Suding
- Institute of Arctic & Alpine Research, Ecology & Evolutionary Biology DepartmentUniversity of ColoradoBoulderColorado
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17
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Hall LE, Chalfoun AD. Behavioural plasticity modulates temperature-related constraints on foraging time for a montane mammal. J Anim Ecol 2018; 88:363-375. [PMID: 30449046 DOI: 10.1111/1365-2656.12925] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Accepted: 09/10/2018] [Indexed: 11/29/2022]
Abstract
Contemporary climate change is altering temperature profiles across the globe. Increasing temperatures can reduce the amount of time during which conditions are suitable for animals to engage in essential activities, such as securing food. Behavioural plasticity, the ability to alter behaviour in response to the environment, may provide animals with a tool to adjust to changes in the availability of suitable thermal conditions. The extent to which individuals can alter fitness-enhancing behaviours, such as food collection, to proximately buffer variation in temperature, however, remains unclear. Even less well understood are the potential performance advantages of flexible strategies among endotherms. We examined the degree to which individuals altered rates of food collection in response to temperature, and two potential benefits, using the American pika (Ochotona princeps), a temperature-sensitive, food-hoarding mammal, as a model. From July-September 2013-2015, we used motion-activated cameras and in situ temperature loggers to examine pika food-caching activity for 72 individuals across 10 sites in the central Rocky Mountains, USA. We quantified % nitrogen by cache volume as a metric of cache quality, and the number of events during which pikas were active in temperatures ≥25°C as a measure of potential thermoregulatory stress. We found a strong negative effect of temperature on the rate at which pikas cached food. Individual responses to temperature varied substantially in both the level of food-collecting activity and in the degree to which individuals shifted activity with warming temperature. After accounting for available foraging time, individuals that exhibited greater plasticity collected a comparable amount of nitrogen, while simultaneously experiencing fewer occasions in which temperatures eclipsed estimated thermal tolerances. By varying food-collection norms of reaction, individuals were able to plastically respond to temperature-driven reductions in foraging time. Through this increased flexibility, individuals amassed food caches of comparable quality, while minimizing exposure to potentially stressful thermal conditions. Our results suggest that, given sufficient resource quality and availability, plasticity in foraging activity may help temperature-limited endotherms adjust to climate-related constraints on foraging time.
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Affiliation(s)
- L Embere Hall
- Wyoming Cooperative Fish and Wildlife Research Unit, Department of Zoology and Physiology and Program in Ecology, University of Wyoming, Laramie, Wyoming
| | - Anna D Chalfoun
- U.S. Geological Survey, Wyoming Cooperative Fish and Wildlife Research Unit, Department of Zoology and Physiology and Program in Ecology, University of Wyoming, Laramie, Wyoming
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19
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Stratton JJ, Ham J, Borch T. Ammonia Emissions from Subalpine Forest and Mountain Grassland Soils in Rocky Mountain National Park. JOURNAL OF ENVIRONMENTAL QUALITY 2018; 47:778-785. [PMID: 30025059 DOI: 10.2134/jeq2018.01.0023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Atmospheric deposition of NH and NH contributes to eutrophication within sensitive subalpine ecosystems of Rocky Mountain National Park (RMNP) in the United States. However, little is known about the local contribution of NH from soils within the park. Thus, the goal of this study was to quantify and compare NH emissions from intact soil cores sampled from a subalpine grassland and forest within RMNP. Cores were collected at 2-wk intervals from 20 June 2011 to 12 Sept. 2011 and transferred to a laboratory chamber system for NH flux measurements. Additionally, N wet deposition was monitored at the sampling location to investigate possible impacts on NH soil emissions. The average quantifiable NH emissions (with SDs) from intact soil cores analyzed in the laboratory (23°C) were 0.42 ± 0.30 mg NH-N m d for grassland soil and 0.21 ± 0.03 mg NH-N m d for forest soil ( < 0.001). A mechanistic model was developed to estimate the impact of temperature on soil emissions using the chamber data and field-site air temperatures. Average estimated NH emissions from the field site over the study period were 0.21 and 0.082 mg NH-N m d for grasslands and forests, respectively. Ammonium wet deposition was not correlated to short term reemission of NH based on N isotope analysis. This work provides new information on the magnitude of NH emissions from native subalpine soils, indicating that natural emissions are not likely major sources of NH in the RMNP airshed.
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20
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Zhang Z, Goldstein HL, Reynolds RL, Hu Y, Wang X, Zhu M. Phosphorus Speciation and Solubility in Aeolian Dust Deposited in the Interior American West. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:2658-2667. [PMID: 29421873 DOI: 10.1021/acs.est.7b04729] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Aeolian dust is a significant source of phosphorus (P) to alpine oligotrophic lakes, but P speciation in dust and source sediments and its release kinetics to lake water remain unknown. Phosphorus K-edge XANES spectroscopy shows that calcium-bound P (Ca-P) is dominant in 10 of 12 dust samples (41-74%) deposited on snow in the central Rocky Mountains and all 42 source sediment samples (the fine fraction) (68-80%), with a lower proportion in dust probably because acidic snowmelt dissolves some Ca-P in dust before collection. Iron-bound P (Fe-P, ∼54%) dominates in the remaining two dust samples. Chemical extractions (SEDEX) on these samples provide inaccurate results because of unselective extraction of targeted species and artifacts introduced by the extractions. Dust releases increasingly more P in synthetic lake water within 6-72 h thanks to dissolution of Ca-P, but dust release of P declines afterward due to back adsorption of P onto Fe oxides present in the dust. The back sorption is stronger for the dust with a lower degree of P saturation determined by oxalate extraction. This work suggests that P speciation, poorly crystalline minerals in the dust, and lake acidification all affect the availability and fate of dust-borne P in lakes.
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Affiliation(s)
- Zhuojun Zhang
- Department of Ecosystem Science and Management , University of Wyoming , Laramie , Wyoming 82071 , United States
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry , Chinese Academy of Sciences , Guiyang 550081 , China
- University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Harland L Goldstein
- Geosciences and Environmental Change Science Center , U.S. Geological Survey , Denver , Colorado 80225 , United States
| | - Richard L Reynolds
- Geosciences and Environmental Change Science Center , U.S. Geological Survey , Denver , Colorado 80225 , United States
| | - Yongfeng Hu
- Canadian Light Source Incorporated , University of Saskatchewan , Saskatoon , Saskatchewan S7N 2V3 , Canada
| | - Xiaoming Wang
- Department of Ecosystem Science and Management , University of Wyoming , Laramie , Wyoming 82071 , United States
| | - Mengqiang Zhu
- Department of Ecosystem Science and Management , University of Wyoming , Laramie , Wyoming 82071 , United States
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21
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Hall LE, Chalfoun AD. What to eat in a warming world: do increased temperatures necessitate hazardous duty pay? Oecologia 2017; 186:73-84. [DOI: 10.1007/s00442-017-3993-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Accepted: 10/24/2017] [Indexed: 10/18/2022]
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22
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Jakopak RP, Hall LE, Chalfoun AD. Organizing the pantry: cache management improves quality of overwinter food stores in a montane mammal. J Mammal 2017. [DOI: 10.1093/jmammal/gyx124] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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24
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Clark CM, Bell MD, Boyd JW, Compton JE, Davidson EA, Davis C, Fenn ME, Geiser L, Jones L, Blett TF. Nitrogen‐induced terrestrial eutrophication: cascading effects and impacts on ecosystem services. Ecosphere 2017. [DOI: 10.1002/ecs2.1877] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Christopher M. Clark
- National Center for Environmental Assessment Office of Research and Development U.S. EPA Washington D.C. 20460 USA
| | - Michael D. Bell
- Air Resources Division National Park Service Lakewood Colorado 80225 USA
| | | | - Jana E. Compton
- Western Ecology Division Office of Research and Development U.S. EPA Corvallis Oregon 97333 USA
| | - Eric A. Davidson
- Appalachian Laboratory University of Maryland Center for Environmental Science Frostburg Maryland 21532 USA
| | - Christine Davis
- Office of Air and Radiation, Office of Air Quality Planning and Standards U.S. EPA Research Triangle Park North Carolina 27709 USA
| | - Mark E. Fenn
- Pacific Southwest Research Station USDA Forest Service Riverside California 92607 USA
| | - Linda Geiser
- Washington Office‐Water Wildlife Fish Air and Rare Plants USDA Forest Service Washington D.C. 20250 USA
| | - Laurence Jones
- Environment Centre Wales Centre for Ecology and Hydrology Deiniol Road Bangor LL57 2UW United Kingdom
| | - Tamara F. Blett
- Air Resources Division National Park Service Lakewood Colorado 80225 USA
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25
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Xiao L, Liu G, Li P, Xue S. Elevated CO 2 and nitrogen addition have minimal influence on the rhizospheric effects of Bothriochloa ischaemum. Sci Rep 2017; 7:6527. [PMID: 28747784 PMCID: PMC5529374 DOI: 10.1038/s41598-017-06994-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Accepted: 06/21/2017] [Indexed: 11/15/2022] Open
Abstract
The influence of elevated CO2 and nitrogen (N) addition on soil microbial communities and the rhizospheric effects of Bothriochloa ischaemum were investigated. A pot-cultivation experiment was conducted in climate-controlled chambers under two levels of CO2 (400 and 800 μmol mol−1) and three levels of N addition (0, 2.5, and 5 g N m−2 y−1). Soil samples (rhizospheric and bulk soil) were collected for the assessment of soil organic carbon (SOC), total N (TN), total phosphorus (TP), basal respiration (BR), and phospholipid fatty acids (PLFAs) 106 days after treatments were conducted. Elevated CO2 significantly increased total and fungal PLFAs in the rhizosphere when combined with N addition, and N addition significantly increased BR in the rhizosphere and total, bacterial, fungal, Gram-positive (G+), and Gram-negative (G−) PLFAs in both rhizospheric and bulk soil. BR and total, bacterial, G+, and G+/G− PLFAs were significantly higher in rhizospheric than bulk soil, but neither elevated CO2 nor N addition affected the positive rhizospheric effects on bacterial, G+, or G+/G− PLFAs. N addition had a greater effect on soil microbial communities than elevated CO2, and elevated CO2 and N addition had minor contributions to the changes in the magnitude of the rhizospheric effects in B. ischaemum.
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Affiliation(s)
- Lie Xiao
- State Key Laboratory Base of Eco-hydraulic Engineering in Arid Area, Xi'an University of Technology, Xi'an, 710048, China.,State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling, 712100, China
| | - Guobin Liu
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling, 712100, China
| | - Peng Li
- State Key Laboratory Base of Eco-hydraulic Engineering in Arid Area, Xi'an University of Technology, Xi'an, 710048, China
| | - Sha Xue
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling, 712100, China.
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Matteodo M, Ammann K, Verrecchia EP, Vittoz P. Snowbeds are more affected than other subalpine-alpine plant communities by climate change in the Swiss Alps. Ecol Evol 2016; 6:6969-6982. [PMID: 28725374 PMCID: PMC5513224 DOI: 10.1002/ece3.2354] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Revised: 06/23/2016] [Accepted: 06/30/2016] [Indexed: 11/27/2022] Open
Abstract
While the upward shift of plant species has been observed on many alpine and nival summits, the reaction of the subalpine and lower alpine plant communities to the current warming and lower snow precipitation has been little investigated so far. To this aim, 63 old, exhaustive plant inventories, distributed along a subalpine–alpine elevation gradient of the Swiss Alps and covering different plant community types (acidic and calcareous grasslands; windy ridges; snowbeds), were revisited after 25–50 years. Old and recent inventories were compared in terms of species diversity with Simpson diversity and Bray–Curtis dissimilarity indices, and in terms of community composition with principal component analysis. Changes in ecological conditions were inferred from the ecological indicator values. The alpha‐diversity increased in every plant community, likely because of the arrival of new species. As observed on mountain summits, the new species led to a homogenization of community compositions. The grasslands were quite stable in terms of species composition, whatever the bedrock type. Indeed, the newly arrived species were part of the typical species pool of the colonized community. In contrast, snowbed communities showed pronounced vegetation changes and a clear shift toward dryer conditions and shorter snow cover, evidenced by their colonization by species from surrounding grasslands. Longer growing seasons allow alpine grassland species, which are taller and hence more competitive, to colonize the snowbeds. This study showed that subalpine–alpine plant communities reacted differently to the ongoing climate changes. Lower snow/rain ratio and longer growing seasons seem to have a higher impact than warming, at least on plant communities dependent on long snow cover. Consequently, they are the most vulnerable to climate change and their persistence in the near future is seriously threatened. Subalpine and alpine grasslands are more stable, and, until now, they do not seem to be affected by a warmer climate.
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Affiliation(s)
- Magalì Matteodo
- Institute of Earth Surface Dynamics (IDYST) University of Lausanne Géopolis Building 1015 Lausanne Switzerland
| | - Klaus Ammann
- Prof. Emeritus University of Bern Monruz 202000 Neuchâtel Switzerland
| | - Eric Pascal Verrecchia
- Institute of Earth Surface Dynamics (IDYST) University of Lausanne Géopolis Building 1015 Lausanne Switzerland
| | - Pascal Vittoz
- Institute of Earth Surface Dynamics (IDYST) University of Lausanne Géopolis Building 1015 Lausanne Switzerland
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Yuan X, Knelman JE, Gasarch E, Wang D, Nemergut DR, Seastedt TR. Plant community and soil chemistry responses to long-term nitrogen inputs drive changes in alpine bacterial communities. Ecology 2016; 97:1543-54. [PMID: 27459784 DOI: 10.1890/15-1160.1] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Bacterial community composition and diversity was studied in alpine tundra soils across a plant species and moisture gradient in 20 y-old experimental plots with four nutrient addition regimes (control, nitrogen (N), phosphorus (P) or both nutrients). Different bacterial communities inhabited different alpine meadows, reflecting differences in moisture, nutrients and plant species. Bacterial community alpha-diversity metrics were strongly correlated with plant richness and the production of forbs. After meadow type, N addition proved the strongest determinant of bacterial community structure. Structural Equation Modeling demonstrated that tundra bacterial community responses to N addition occur via changes in plant community composition and soil pH resulting from N inputs, thus disentangling the influence of direct (resource availability) vs. indirect (changes in plant community structure and soil pH) N effects that have remained unexplored in past work examining bacterial responses to long-term N inputs in these vulnerable environments. Across meadow types, the relative influence of these indirect N effects on bacterial community structure varied. In explicitly evaluating the relative importance of direct and indirect effects of long-term N addition on bacterial communities, this study provides new mechanistic understandings of the interaction between plant and microbial community responses to N inputs amidst environmental change.
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28
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Imposing antecedent global change conditions rapidly alters plant community composition in a mixed-grass prairie. Oecologia 2016; 182:899-911. [DOI: 10.1007/s00442-016-3684-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Accepted: 06/15/2016] [Indexed: 10/21/2022]
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Zong N, Shi P, Song M, Zhang X, Jiang J, Chai X. Nitrogen Critical Loads for an Alpine Meadow Ecosystem on the Tibetan Plateau. ENVIRONMENTAL MANAGEMENT 2016; 57:531-42. [PMID: 26475686 DOI: 10.1007/s00267-015-0626-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2015] [Accepted: 09/29/2015] [Indexed: 05/23/2023]
Abstract
Increasing atmospheric nitrogen (N) deposition has the potential to alter plant diversity and thus the function and stability of terrestrial ecosystems. N-limited alpine ecosystems are expected to be particularly susceptible to increasing N deposition. However, little is known about the critical loads and saturation thresholds of ecosystem responses to increasing N deposition on the Tibetan Plateau, despite its importance to ecosystem management. To evaluate the N critical loads and N saturation thresholds in an alpine ecosystem, in 2010, we treated an alpine meadow with five levels of N addition (0, 10, 20, 40, and 80 kg N ha(-1) year(-1)) and characterized plant and soil responses. The results showed that plant species richness and diversity index did not statistically vary with N addition treatments, but they both changed with years. N addition affected plant cover and aboveground productivity, especially for grasses, and soil chemical features. The N critical loads and saturation thresholds, in terms of plant cover and biomass change at the community level, were 8.8-12.7 and 50 kg N ha(-1) year(-1) (including the ambient N deposition rate), respectively. However, pronounced changes in soil inorganic N and net N mineralization occurred under the 20 and 40 kg N ha(-1) year(-1) treatments. Our results indicate that plant community cover and biomass are more sensitive than soil to increasing N inputs. The plant community composition in alpine ecosystems on the Qinghai-Tibetan Plateau may change under increasing N deposition in the future.
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Affiliation(s)
- Ning Zong
- Lhasa National Ecological Research Station, Key Laboratory of Ecosystem Network Observation and Modelling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, 11A, Datun Road, Chaoyang District, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Peili Shi
- Lhasa National Ecological Research Station, Key Laboratory of Ecosystem Network Observation and Modelling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, 11A, Datun Road, Chaoyang District, Beijing, 100101, China.
| | - Minghua Song
- Key Laboratory of Ecosystem Network Observation and Modelling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China
| | - Xianzhou Zhang
- Lhasa National Ecological Research Station, Key Laboratory of Ecosystem Network Observation and Modelling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, 11A, Datun Road, Chaoyang District, Beijing, 100101, China
| | - Jing Jiang
- Nanjing Agricultural Institute of Jiangsu Hilly Region, Nanjing, 210046, Jiangsu, China
| | - Xi Chai
- Lhasa National Ecological Research Station, Key Laboratory of Ecosystem Network Observation and Modelling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, 11A, Datun Road, Chaoyang District, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
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Humbert JY, Dwyer JM, Andrey A, Arlettaz R. Impacts of nitrogen addition on plant biodiversity in mountain grasslands depend on dose, application duration and climate: a systematic review. GLOBAL CHANGE BIOLOGY 2016; 22:110-120. [PMID: 26010833 DOI: 10.1111/gcb.12986] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Revised: 04/15/2015] [Accepted: 05/17/2015] [Indexed: 05/28/2023]
Abstract
Although the influence of nitrogen (N) addition on grassland plant communities has been widely studied, it is still unclear whether observed patterns and underlying mechanisms are constant across biomes. In this systematic review, we use meta-analysis and metaregression to investigate the influence of N addition (here referring mostly to fertilization) upon the biodiversity of temperate mountain grasslands (including montane, subalpine and alpine zones). Forty-two studies met our criteria of inclusion, resulting in 134 measures of effect size. The main general responses of mountain grasslands to N addition were increases in phytomass and reductions in plant species richness, as observed in lowland grasslands. More specifically, the analysis reveals that negative effects on species richness were exacerbated by dose (ha(-1) year(-1) ) and duration of N application (years) in an additive manner. Thus, sustained application of low to moderate levels of N over time had effects similar to short-term application of high N doses. The climatic context also played an important role: the overall effects of N addition on plant species richness and diversity (Shannon index) were less pronounced in mountain grasslands experiencing cool rather than warm summers. Furthermore, the relative negative effect of N addition on species richness was more pronounced in managed communities and was strongly negatively related to N-induced increases in phytomass, that is the greater the phytomass response to N addition, the greater the decline in richness. Altogether, this review not only establishes that plant biodiversity of mountain grasslands is negatively affected by N addition, but also demonstrates that several local management and abiotic factors interact with N addition to drive plant community changes. This synthesis yields essential information for a more sustainable management of mountain grasslands, emphasizing the importance of preserving and restoring grasslands with both low agricultural N application and limited exposure to N atmospheric deposition.
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Affiliation(s)
- Jean-Yves Humbert
- Division of Conservation Biology, Institute of Ecology and Evolution, University of Bern, Baltzerstrasse 6, 3012, Bern, Switzerland
- School of Biological Sciences, The University of Queensland, St Lucia, Qld, 4072, Australia
| | - John M Dwyer
- Division of Conservation Biology, Institute of Ecology and Evolution, University of Bern, Baltzerstrasse 6, 3012, Bern, Switzerland
- School of Biological Sciences, The University of Queensland, St Lucia, Qld, 4072, Australia
- CSIRO Land and Water Flagship, EcoSciences Precinct, Dutton Park, Qld, 4102, Australia
| | - Aline Andrey
- Division of Conservation Biology, Institute of Ecology and Evolution, University of Bern, Baltzerstrasse 6, 3012, Bern, Switzerland
| | - Raphaël Arlettaz
- Division of Conservation Biology, Institute of Ecology and Evolution, University of Bern, Baltzerstrasse 6, 3012, Bern, Switzerland
- Swiss Ornithological Institute, Valais Field Station, Rue du Rhône 11, 1950, Sion, Switzerland
- Instituto Argentino de Investigaciones de las Zonas Áridas, CONICET, CC 507, 5500, Mendoza, Argentina
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Otero XL, Tejada O, Martín-Pastor M, De La Peña S, Ferreira TO, Pérez-Alberti A. Phosphorus in seagull colonies and the effect on the habitats. The case of yellow-legged gulls (Larus michahellis) in the Atlantic Islands National Park (Galicia-NW Spain). THE SCIENCE OF THE TOTAL ENVIRONMENT 2015; 532:383-397. [PMID: 26081740 DOI: 10.1016/j.scitotenv.2015.06.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2015] [Revised: 06/02/2015] [Accepted: 06/03/2015] [Indexed: 06/04/2023]
Abstract
During the period 1980-2000, the yellow-legged gull population underwent exponential growth due to an increase in the availability of anthropogenic food resources. The aim of this study was to highlight the effect of the gull colonies on the P soil cycle and the associated effects on coastal ecosystems. Samples of soil, water and faecal material were collected in a colony of yellow-legged gulls (Cíes Islands) and in a control area. Four sampling plots were installed in the study areas, and samples were collected in summer and winter in 1997 and 2011. Sample analysis included soil characterization and determination of the total P content (TP), bioavailable-P and fractionated-P forms in the soils and faecal material. The (31)P NMR technique was also used to determine organic P forms. Clear differences between the gull colony soils and the control soil were observed. The TP was 3 times higher in the gull colony soil, and the bioavailable P was 30 times higher than in the control soil. The P forms present at highest concentrations in the faecal material (P-apatite, P-residual and P-humic acid) were also present at high concentrations in the colony soil. The absence of any seasonal or annual differences in P concentration indicates that the P has remained stable in the soil over time, regardless of the changes in the gull population density. The degree of P saturation indicated that soils are saturated with P due to the low concentration of Fe/Al-hydroxides, which is consistent with a high P concentration in the run-off from the colonies. The P output from the colony soils to coastal waters may cause eutrophication of a nearby lagoon and the disappearance of a Zostera marina seagrass meadow. Similarly, the enrichment of P concentration in dune system of Muxieiro may induce irreversible changes in the plant communities.
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Affiliation(s)
- X L Otero
- Departamento de Edafoloxía e Química Agrícola, Facultade de Bioloxía, Universidade de Santiago de Compostela, Spain; Departamento de Tecnología de Ciencia de los Alimentos y Biotecnología. Universidad Politécnica Nacional, Quito, Ecuador.
| | - O Tejada
- Departamento de Edafoloxía e Química Agrícola, Facultade de Bioloxía, Universidade de Santiago de Compostela, Spain
| | - M Martín-Pastor
- Rede de Infraestruturas de Apoio á Investigación e ao Desenvolvemento Tecnolóxico (RIAIDT), Edificio Cactus, Universidad de Santiago de Compostela, Spain
| | - S De La Peña
- Departamento de Edafoloxía e Química Agrícola, Facultade de Bioloxía, Universidade de Santiago de Compostela, Spain
| | - T O Ferreira
- Departamento de Ciência do Solo, Universidade de São Paulo, 13418-900 Piracicaba, SP, Brazil
| | - A Pérez-Alberti
- Departamento de Xeografía, Facultade de Xeografía e Historia, Universidade de Santiago de Compostela, Spain
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Concilio AL, Prevéy JS, Omasta P, O'Connor J, Nippert JB, Seastedt TR. Response of a mixed grass prairie to an extreme precipitation event. Ecosphere 2015. [DOI: 10.1890/es15-00073.1] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Puchalski MA, Rogers CM, Baumgardner R, Mishoe KP, Price G, Smith MJ, Watkins N, Lehmann CM. A statistical comparison of active and passive ammonia measurements collected at Clean Air Status and Trends Network (CASTNET) sites. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2015; 17:358-69. [PMID: 25574663 DOI: 10.1039/c4em00531g] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Atmospheric concentrations of ammonia (NH3) are not well characterized in the United States due to the sparse number of monitors, the relatively short lifetime of NH3 in the atmosphere, and the difficulty in measuring non-point source emissions such as fertilized agricultural land. In this study, we compare measured weekly concentrations of NH3 collected by two denuder systems with a bi-weekly passive NH3 sampler used by the National Atmospheric Deposition Program's (NADP) Ammonia Monitoring Network (AMoN). The purpose of the study was to verify the passive samplers used by AMoN and characterize any uncertainties introduced when using a bi-weekly versus weekly sampling time period. The study was conducted for 1 year at five remote Clean Air Status and Trends Network (CASTNET) sites. Measured ambient NH3 concentrations ranged from 0.03 μg NH3 m(-3) to 4.64 μg NH3 m(-3) in upstate New York and northwest Texas, respectively, while dry deposition estimates ranged from 0.003 kg N ha(-1) wk(-1) to 0.47 kg N ha(-1) wk(-1). Results showed that the bi-weekly passive samplers performed well compared to annular denuder systems (ADS) deployed at each of the five CASTNET sites, while the MetOne Super SASS Mini-Parallel Plate Denuder System (MPPD) was biased low when compared to the ADS. The mean relative percent difference (MRPD) between the ADS and MPPD and the ADS and AMoN sampler was -38% and -9%, respectively. Precision of the ADS and MPPD was 5% and 13%, respectively, while the precision of the passive samplers was 5%. The results of this study demonstrate that the NH3 concentrations measured by AMoN are comparable to the ADS and may be used to supplement the high-time resolution measurements to gain information on spatial gradients of NH3, long-term trends and seasonal variations in NH3 concentrations.
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Affiliation(s)
- Melissa A Puchalski
- U.S. EPA Office of Air Programs, 1200 Pennsylvania Ave NW, Washington D.C. 20460, USA.
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Hu Z, Anderson NJ, Yang X, McGowan S. Catchment-mediated atmospheric nitrogen deposition drives ecological change in two alpine lakes in SE Tibet. GLOBAL CHANGE BIOLOGY 2014; 20:1614-28. [PMID: 24132882 DOI: 10.1111/gcb.12435] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Accepted: 09/04/2013] [Indexed: 05/20/2023]
Abstract
The south-east margin of Tibet is highly sensitive to global environmental change pressures, in particular, high contemporary reactive nitrogen (Nr) deposition rates (ca. 40 kg ha(-1) yr(-1) ), but the extent and timescale of recent ecological change is not well prescribed. Multiproxy analyses (diatoms, pigments and geochemistry) of (210) Pb-dated sediment cores from two alpine lakes in Sichuan were used to assess whether they have undergone ecological change comparable to those in Europe and North America over the last two centuries. The study lakes have contrasting catchment-to-lake ratios and vegetation cover: Shade Co has a relatively larger catchment and denser alpine shrub than Moon Lake. Both lakes exhibited unambiguous increasing production since the late 19th to early 20th. Principle component analysis was used to summarize the trends of diatom and pigment data after the little ice age (LIA). There was strong linear change in biological proxies at both lakes, which were not consistent with regional temperature, suggesting that climate is not the primary driver of ecological change. The multiproxy analysis indicated an indirect ecological response to Nr deposition at Shade Co mediated through catchment processes since ca. 1930, while ecological change at Moon Lake started earlier (ca. 1880) and was more directly related to Nr deposition (depleted δ(15) N). The only pronounced climate effect was evidenced by changes during the LIA when photoautotrophic groups shifted dramatically at Shade Co (a 4-fold increase in lutein concentration) and planktonic diatom abundance declined at both sites because of longer ice cover. The substantial increases in aquatic production over the last ca. 100 years required a substantial nutrient subsidy and the geochemical data point to a major role for Nr deposition although dust cannot be excluded. The study also highlights the importance of lake and catchment morphology for determining the response of alpine lakes to recent global environmental forcing.
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Affiliation(s)
- Zhujun Hu
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China; University of Chinese Academy of Sciences, Beijing, 100049, China
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Sullivan TJ, Jenkins J. The science and policy of critical loads of pollutant deposition to protect ecosystems in New York. Ann N Y Acad Sci 2014; 1313:57-68. [DOI: 10.1111/nyas.12407] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | - Jerry Jenkins
- Wildlife Conservation Society; Saranac Lake New York
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Benedict KB, Carrico CM, Kreidenweis SM, Schichtel B, Malm WC, Collett JL. A seasonal nitrogen deposition budget for Rocky Mountain National Park. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2013; 23:1156-1169. [PMID: 23967583 DOI: 10.1890/12-1624.1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Nitrogen deposition is a concern in many protected ecosystems around the world, yet few studies have quantified a complete reactive nitrogen deposition budget including all dry and wet, inorganic and organic compounds. Critical loads that identify the level at which nitrogen deposition negatively affects an ecosystem are often defined using incomplete reactive nitrogen budgets. Frequently only wet deposition of ammonium and nitrate are considered, despite the importance of other nitrogen deposition pathways. Recently, dry deposition pathways including particulate ammonium and nitrate and gas phase nitric acid have been added to nitrogen deposition budgets. However, other nitrogen deposition pathways, including dry deposition of ammonia and wet deposition of organic nitrogen, still are rarely included. In this study, a more complete seasonal nitrogen deposition budget was constructed based on observations during a year-long study period from November 2008 to November 2009 at a location on the east side of Rocky Mountain National Park (RMNP), Colorado, USA. Measurements included wet deposition of ammonium, nitrate, and organic nitrogen, PM2.5 (particulate matter with an aerodynamic diameter less than 2.5 microm, nitrate, and ammonium) concentrations of ammonium, nitrate, and organic nitrogen, and atmospheric gas phase concentrations of ammonia, nitric acid, and NO2. Dry deposition fluxes were determined from measured ambient concentrations and modeled deposition velocities. Total reactive nitrogen deposition by all included pathways was found to be 3.65 kg N x ha(-1) yr(-1). Monthly deposition fluxes ranged from 0.06 to 0.54 kg N x ha(-1)yr(-1), with peak deposition in the month of July and the least deposition in December. Wet deposition of ammonium and nitrate were the two largest deposition pathways, together contributing 1.97 kg N x ha(-1)yr(-1) or 54% of the total nitrogen deposition budget for this region. The next two largest deposition pathways were wet deposition of organic nitrogen and dry deposition of ammonia; combined they contributed 1.37 kg N x ha(-1)yr(-1) or 37% of the total nitrogen deposition budget. To better understand the nitrogen cycle and key interactions between the atmosphere and biosphere we need to include as many sources and types of nitrogen as possible and understand their variability throughout the year. Here we examine the components of the nitrogen deposition budget to better understand the factors that influence the different deposition pathways and their seasonal variations.
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Affiliation(s)
- K B Benedict
- Department of Atmospheric Science, Colorado State University, Fort Collins, Colorado 80523, USA.
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