1
|
Avolio ML, Wilcox KR, Komatsu KJ, Lemoine N, Bowman WD, Collins SL, Knapp AK, Koerner SE, Smith MD, Baer SG, Gross KL, Isbell F, McLaren J, Reich PB, Suding KN, Suttle KB, Tilman D, Xu Z, Yu Q. Temporal variability in production is not consistently affected by global change drivers across herbaceous-dominated ecosystems. Oecologia 2020; 194:735-744. [PMID: 33130915 DOI: 10.1007/s00442-020-04787-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Accepted: 10/10/2020] [Indexed: 11/29/2022]
Abstract
Understanding how global change drivers (GCDs) affect aboveground net primary production (ANPP) through time is essential to predicting the reliability and maintenance of ecosystem function and services in the future. While GCDs, such as drought, warming and elevated nutrients, are known to affect mean ANPP, less is known about how they affect inter-annual variability in ANPP. We examined 27 global change experiments located in 11 different herbaceous ecosystems that varied in both abiotic and biotic conditions, to investigate changes in the mean and temporal variability of ANPP (measured as the coefficient of variation) in response to different GCD manipulations, including resource additions, warming, and irrigation. From this comprehensive data synthesis, we found that GCD treatments increased mean ANPP. However, GCD manipulations both increased and decreased temporal variability of ANPP (24% of comparisons), with no net effect overall. These inconsistent effects on temporal variation in ANPP can, in part, be attributed to site characteristics, such as mean annual precipitation and temperature as well as plant community evenness. For example, decreases in temporal variability in ANPP with the GCD treatments occurred in wetter and warmer sites with lower plant community evenness. Further, the addition of several nutrients simultaneously increased the sensitivity of ANPP to interannual variation in precipitation. Based on this analysis, we expect that GCDs will likely affect the magnitude more than the reliability over time of ecosystem production in the future.
Collapse
Affiliation(s)
- Meghan L Avolio
- Department of Earth and Planetary Sciences, Johns Hopkins University, 3400 N. Charles St., Baltimore, MD, 21218, USA.
| | - Kevin R Wilcox
- Department of Ecosystem Science and Management, University of Wyoming, Laramie, WY, 82071, USA
| | - Kimberly J Komatsu
- Smithsonian Environmental Research Center, 647 Contees Wharf Road, Edgewater, MD, 21037, USA
| | - Nathan Lemoine
- Department of Biological Sciences, Marquette University, Milwaukee, WI, 53233, USA.,Department of Zoology, Milwaukee Public Museum, Milwaukee, WI, 53233, USA
| | - William D Bowman
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, 80309, USA
| | - Scott L Collins
- Department of Biology, University of New Mexico, Albuquerque, NM, 87131, USA
| | - Alan K Knapp
- Department of Biology, Colorado State University, Fort Collins, CO, 80523, USA.,Graduate Degree Program in Ecology, Colorado State University, Fort Collins, CO, 80523, USA
| | - Sally E Koerner
- Department of Biology, University of North Carolina Greensboro, Greensboro, NC, 27402, USA
| | - Melinda D Smith
- Department of Biology, Colorado State University, Fort Collins, CO, 80523, USA.,Graduate Degree Program in Ecology, Colorado State University, Fort Collins, CO, 80523, USA
| | - Sara G Baer
- Kansas Biological Survey and Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, KS, 66045, USA
| | - Katherine L Gross
- WK Kellogg Biological Station and Graduate Program in Ecology, Evolutionary Biology and Behavior, Michigan State University, Hickory Corners, MI, 49060, USA
| | - Forest Isbell
- Department of Ecology, Evolution and Behavior, University of Minnesota, Saint Paul, MN, 55108, USA
| | - Jennie McLaren
- Department of Biological Sciences, University of Texas at El Paso, El Paso, Tx, 79968, USA
| | - Peter B Reich
- Department of Forest Resources, University of Minnesota, Saint Paul, MN, 55108, USA.,Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, Australia
| | - Katharine N Suding
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, 80309, USA
| | | | - David Tilman
- Department of Ecology, Evolution and Behavior, University of Minnesota, Saint Paul, MN, 55108, USA
| | - Zhuwen Xu
- Key Laboratory of Grassland Ecology, School of Ecology and Environment, Inner Mongolia University, Hohhot, 010021, China
| | - Qiang Yu
- National Hulunber Grassland Ecosystem Observation and Research Station, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
| |
Collapse
|
2
|
Clark CM, Simkin SM, Allen EB, Bowman WD, Belnap J, Brooks ML, Collins SL, Geiser LH, Gilliam FS, Jovan SE, Pardo LH, Schulz BK, Stevens CJ, Suding KN, Throop HL, Waller DM. Potential vulnerability of 348 herbaceous species to atmospheric deposition of nitrogen and sulfur in the United States. Nat Plants 2019; 5:697-705. [PMID: 31263243 PMCID: PMC10790282 DOI: 10.1038/s41477-019-0442-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Accepted: 05/09/2019] [Indexed: 06/09/2023]
Abstract
Atmospheric nitrogen and sulfur pollution increased over much of the United States during the twentieth century from fossil fuel combustion and industrial agriculture. Despite recent declines, nitrogen and sulfur deposition continue to affect many plant communities in the United States, although which species are at risk remains uncertain. We used species composition data from >14,000 survey sites across the contiguous United States to evaluate the association between nitrogen and sulfur deposition and the probability of occurrence for 348 herbaceous species. We found that the probability of occurrence for 70% of species was negatively associated with nitrogen or sulfur deposition somewhere in the contiguous United States (56% for N, 51% for S). Of the species, 15% and 51% potentially decreased at all nitrogen and sulfur deposition rates, respectively, suggesting thresholds below the minimum deposition they receive. Although more species potentially increased than decreased with nitrogen deposition, increasers tended to be introduced and decreasers tended to be higher-value native species. More vulnerable species tended to be shorter with lower tissue nitrogen and magnesium. These relationships constitute predictive equations to estimate critical loads. These results demonstrate that many herbaceous species may be at risk from atmospheric deposition and can inform improvements to air quality policies in the United States and globally.
Collapse
Affiliation(s)
- Christopher M Clark
- National Center for Environmental Assessment, U.S. Environmental Protection Agency, Washington, DC, USA.
| | - Samuel M Simkin
- Department of Ecology and Evolutionary Biology and INSTAAR, University of Colorado, Boulder, CO, USA
- National Ecological Observatory Network, Boulder, CO, USA
| | - Edith B Allen
- Department of Botany and Plant Sciences, University of California, Riverside, CA, USA
| | - William D Bowman
- Department of Ecology and Evolutionary Biology and INSTAAR, University of Colorado, Boulder, CO, USA
| | - Jayne Belnap
- Southwest Biological Science Center, US Geological Survey, Moab, UT, USA
| | - Matthew L Brooks
- Western Ecological Research Center, US Geological Survey, Oakhurst, CA, USA
| | - Scott L Collins
- Department of Biology, University of New Mexico, Albuquerque, NM, USA
| | - Linda H Geiser
- Washington Office-Water, Fish, Wildlife, Air & Rare Plants, USDA Forest Service, Washington, DC, USA
| | - Frank S Gilliam
- Department of Biology, University of West Florida, Pensacola, FL, USA
| | - Sarah E Jovan
- Forest Inventory and Analysis Program, USDA Forest Service, Portland, OR, USA
| | - Linda H Pardo
- Northern Research Station, USDA Forest Service, Burlington, VT, USA
| | - Bethany K Schulz
- Forest Inventory and Analysis Program, USDA Forest Service, Anchorage, AK, USA
| | - Carly J Stevens
- Lancaster Environment Centre, Lancaster University, Lancaster, UK
| | - Katharine N Suding
- Department of Ecology & Evolutionary Biology, University of Colorado, Boulder, USA
| | - Heather L Throop
- School of Earth and Space Exploration, Arizona State University, Tempe, AZ, USA
- School of Life Sciences, Arizona State University, Tempe, AZ, USA
| | - Donald M Waller
- Department of Botany, University of Wisconsin, Madison, WI, USA
| |
Collapse
|
3
|
Potter TS, Owens WM, Bowman WD. Do plant–microbe interactions and aluminum tolerance influence alpine sedge species’ responses to nitrogen deposition? Ecosphere 2019. [DOI: 10.1002/ecs2.2775] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Affiliation(s)
- Teal S. Potter
- Department of Ecology and Evolutionary Biology University of Colorado Boulder Colorado 80309‐0334 USA
| | - William M. Owens
- Department of Ecology and Evolutionary Biology University of Colorado Boulder Colorado 80309‐0334 USA
| | - William D. Bowman
- Department of Ecology and Evolutionary Biology University of Colorado Boulder Colorado 80309‐0334 USA
- Institute of Arctic and Alpine Research University of Colorado Boulder Colorado 80309‐0450 USA
- Mountain Research Station University of Colorado Nederland Colorado 80466 USA
| |
Collapse
|
4
|
Langley JA, Chapman SK, La Pierre KJ, Avolio M, Bowman WD, Johnson DS, Isbell F, Wilcox KR, Foster BL, Hovenden MJ, Knapp AK, Koerner SE, Lortie CJ, Megonigal JP, Newton PCD, Reich PB, Smith MD, Suttle KB, Tilman D. Ambient changes exceed treatment effects on plant species abundance in global change experiments. Glob Chang Biol 2018; 24:5668-5679. [PMID: 30369019 DOI: 10.1111/gcb.14442] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2018] [Accepted: 08/02/2018] [Indexed: 06/08/2023]
Abstract
The responses of species to environmental changes will determine future community composition and ecosystem function. Many syntheses of global change experiments examine the magnitude of treatment effect sizes, but we lack an understanding of how plant responses to treatments compare to ongoing changes in the unmanipulated (ambient or background) system. We used a database of long-term global change studies manipulating CO2 , nutrients, water, and temperature to answer three questions: (a) How do changes in plant species abundance in ambient plots relate to those in treated plots? (b) How does the magnitude of ambient change in species-level abundance over time relate to responsiveness to global change treatments? (c) Does the direction of species-level responses to global change treatments differ from the direction of ambient change? We estimated temporal trends in plant abundance for 791 plant species in ambient and treated plots across 16 long-term global change experiments yielding 2,116 experiment-species-treatment combinations. Surprisingly, for most species (57%) the magnitude of ambient change was greater than the magnitude of treatment effects. However, the direction of ambient change, whether a species was increasing or decreasing in abundance under ambient conditions, had no bearing on the direction of treatment effects. Although ambient communities are inherently dynamic, there is now widespread evidence that anthropogenic drivers are directionally altering plant communities in many ecosystems. Thus, global change treatment effects must be interpreted in the context of plant species trajectories that are likely driven by ongoing environmental changes.
Collapse
Affiliation(s)
- J Adam Langley
- Department of Biology, Villanova University, Villanova, Pennsylvania
| | | | | | - Meghan Avolio
- Department of Earth & Planetary Sciences, Johns Hopkins University, Baltimore, Maryland
| | - William D Bowman
- Department of Ecology and Evolutionary Biology and Mountain Research Station, University of Colorado, Boulder, Colorado
| | - David S Johnson
- Virginia Institute of Marine Science, Gloucester Point, Virginia
| | - Forest Isbell
- Department of Ecology, Evolution and Behavior, University of Minnesota, Saint Paul, Minnesota
| | - Kevin R Wilcox
- U.S. Department of Agriculture, Agriculture Research Service, Fort Collins, Colorado
| | - Bryan L Foster
- Ecology and Evolutionary Biology and Kansas Biological Survey, University of Kansas, Lawrence, Kansas
| | - Mark J Hovenden
- Biological Sciences, School of Natural Sciences, University of Tasmania, Hobart, Tasmania, Australia
| | - Alan K Knapp
- Department of Biology and Graduate Degree Program in Ecology, Fort Collins, Colorado
| | - Sally E Koerner
- Department of Biology, University of North Carolina Greensboro, Greensboro, North Carolina
| | - Christopher J Lortie
- The National Center for Ecological Analysis and Synthesis, UCSB, Santa Barbara, California
| | | | | | - Peter B Reich
- Department of Forest Resources, University of Minnesota, St. Paul, Minnesota
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, New South Wales, Australia
| | - Melinda D Smith
- Department of Biology and Graduate Degree Program in Ecology, Fort Collins, Colorado
| | - Kenwyn B Suttle
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, California
| | - David Tilman
- Department of Ecology, Evolution and Behavior, University of Minnesota, Saint Paul, Minnesota
| |
Collapse
|
5
|
Bowman WD, Ayyad A, Bueno de Mesquita CP, Fierer N, Potter TS, Sternagel S. Limited ecosystem recovery from simulated chronic nitrogen deposition. Ecol Appl 2018; 28:1762-1772. [PMID: 30179279 DOI: 10.1002/eap.1783] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 05/22/2018] [Accepted: 07/05/2018] [Indexed: 06/08/2023]
Abstract
The realization that anthropogenic nitrogen (N) deposition is causing significant environmental change in many ecosystems has led to lower emissions of reactive N and deposition rates in many regions. However, the impacts of N deposition on terrestrial ecosystems can be long lasting, with significant inertia in the return of the biota and biogeochemical processes to baseline levels. To better understand patterns of recovery and the factors that may contribute to slow or no responses following declines in N deposition, we followed plant species composition, microbial abundance, N cycling rates, soil pH, and pools of NO3- and extractable cations in an impacted alpine ecosystem following cessation of 12-yr experiment increasing N deposition rates by 0, 20, 40, and 60 kg N·ha-1 ·yr-1 . Simulated N deposition had resulted in a tripling in the cover of the nitrophilic species Carex rupestris, while the dominant sedge Kobresia myosuroides had decreased by more than half at the highest N input level. In addition, nitrification rates were elevated, soil extractable magnesium (Mg2+ ) and pH decreased, and aluminum (Al3+ ) and manganese (Mn2+ ) were elevated at the highest N treatment inputs. Over the nine years following cessation of N additions to the impacted plots, only the cover of the nitrophilic C. rupestris showed any recovery to prior levels. Abundances of both bacteria and fungi were lower with N addition in both treatment and recovery plots. Rates of nitrification and pools of NO3- remained elevated in the recovery plots, likely contributing to the lack of biotic response to the cessation of N inputs. In addition, nutrient base cations (Ca2+ and Mg2+ ) and soil pH remained depressed, and the toxic metal cations (Al3+ and Mn2+ ) remained elevated in recovery plots, also potentially influencing biotic recovery. These results emphasize the importance of considering long-term environmental impacts of N deposition associated with legacy effects, such as elevated N cycling and losses of base cations, in determining environmental standards such as the metrics used for critical loads.
Collapse
Affiliation(s)
- William D Bowman
- Department of Ecology and Evolutionary Biology and Institute of Arctic and Alpine Research, University of Colorado, Boulder, Colorado, 80309-0334, USA
| | - Asma Ayyad
- Department of Botany and Plant Sciences, University of California, Riverside, California, 92521, USA
| | - Clifton P Bueno de Mesquita
- Department of Ecology and Evolutionary Biology and Institute of Arctic and Alpine Research, University of Colorado, Boulder, Colorado, 80309-0334, USA
| | - Noah Fierer
- Department of Ecology and Evolutionary Biology and Institute of Arctic and Alpine Research, University of Colorado, Boulder, Colorado, 80309-0334, USA
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado, 80309-0216, USA
| | - Teal S Potter
- Department of Ecology and Evolutionary Biology and Institute of Arctic and Alpine Research, University of Colorado, Boulder, Colorado, 80309-0334, USA
| | - Stefanie Sternagel
- Department of Ecology and Evolutionary Biology and Institute of Arctic and Alpine Research, University of Colorado, Boulder, Colorado, 80309-0334, USA
| |
Collapse
|
6
|
Wilcox KR, Tredennick AT, Koerner SE, Grman E, Hallett LM, Avolio ML, La Pierre KJ, Houseman GR, Isbell F, Johnson DS, Alatalo JM, Baldwin AH, Bork EW, Boughton EH, Bowman WD, Britton AJ, Cahill JF, Collins SL, Du G, Eskelinen A, Gough L, Jentsch A, Kern C, Klanderud K, Knapp AK, Kreyling J, Luo Y, McLaren JR, Megonigal P, Onipchenko V, Prevéy J, Price JN, Robinson CH, Sala OE, Smith MD, Soudzilovskaia NA, Souza L, Tilman D, White SR, Xu Z, Yahdjian L, Yu Q, Zhang P, Zhang Y. Asynchrony among local communities stabilises ecosystem function of metacommunities. Ecol Lett 2017; 20:1534-1545. [PMID: 29067791 PMCID: PMC6849522 DOI: 10.1111/ele.12861] [Citation(s) in RCA: 83] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2017] [Revised: 08/01/2017] [Accepted: 09/06/2017] [Indexed: 11/30/2022]
Abstract
Temporal stability of ecosystem functioning increases the predictability and reliability of ecosystem services, and understanding the drivers of stability across spatial scales is important for land management and policy decisions. We used species‐level abundance data from 62 plant communities across five continents to assess mechanisms of temporal stability across spatial scales. We assessed how asynchrony (i.e. different units responding dissimilarly through time) of species and local communities stabilised metacommunity ecosystem function. Asynchrony of species increased stability of local communities, and asynchrony among local communities enhanced metacommunity stability by a wide range of magnitudes (1–315%); this range was positively correlated with the size of the metacommunity. Additionally, asynchronous responses among local communities were linked with species’ populations fluctuating asynchronously across space, perhaps stemming from physical and/or competitive differences among local communities. Accordingly, we suggest spatial heterogeneity should be a major focus for maintaining the stability of ecosystem services at larger spatial scales.
Collapse
Affiliation(s)
- Kevin R Wilcox
- Department of Microbiology and Plant Biology, University of Oklahoma, 770 Van Vleet Oval, Norman, OK, 73019, USA
| | - Andrew T Tredennick
- Department of Wildland Resources and the Ecology Center, Utah State University, 5230 Old Main Hill, Logan, UT, 84321, USA
| | - Sally E Koerner
- Department of Biology, University of North Carolina Greensboro, Greensboro, NC, 27412, USA
| | - Emily Grman
- Biology Department, Eastern Michigan University, 441 Mark Jefferson Science Complex, Ypsilanti, MI, 48197, USA
| | - Lauren M Hallett
- Environmental Studies Program and Department of Biology, University of Oregon, Eugene, OR, 97403, USA
| | - Meghan L Avolio
- Morton K. Blaustein Department of Earth and Planetary Sciences, Johns Hopkins University, 301 Olin Hall 3400 N. Charles Street, Baltimore, MD, 21218, USA
| | - Kimberly J La Pierre
- Smithsonian Environmental Research Center, 647 Contees Wharf Road, Edgewater, MD, 21037, USA
| | - Gregory R Houseman
- Department of Biological Sciences, Wichita State University, Wichita, KS, 67260, USA
| | - Forest Isbell
- Department of Ecology, Evolution and Behavior, University of Minnesota, Saint Paul, MN, 55108, USA
| | | | - Juha M Alatalo
- Department of Biological and Environmental Sciences, Qatar University, Doha, Qatar
| | - Andrew H Baldwin
- Department of Environmental Science and Technology, University of Maryland, College Park, MD, 20742, USA
| | - Edward W Bork
- Agriculture/Forestry Center, University of Alberta, Edmonton, Alberta, Canada, T6G 2P5
| | - Elizabeth H Boughton
- Archbold Biological Station, MacArthur Agroecology Research Center, 300 Buck Island Ranch Road, Lake Placid, FL, 33852, USA
| | - William D Bowman
- Department of Ecology and Evolutionary Biology and Mountain Research Station, University of Colorado, Boulder, CO, 80309, USA
| | - Andrea J Britton
- The James Hutton Institute, Craigiebuckler, Aberdeen, AB15 8QH, UK
| | - James F Cahill
- Department of Biological Sciences, University of Alberta, Edmonton, AB, T6G 2E9, Canada
| | - Scott L Collins
- Department of Biology, University of New Mexico, Albuquerque, NM, 87131, USA
| | - Guozhen Du
- School of Life Science, Lanzhou University, Lanzhou, Gansu, China
| | - Anu Eskelinen
- Department of Physiological Diversity, Helmholtz Center for Environmental Research - UFZ, Permoserstr. 15, D-04318, Leipzig, Germany.,German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena- Leipzig, Deutscher Platz 5e, D-04103, Leipzig, Germany.,Department of Ecology, University of Oulu, P.O. Box 3000, FI-90014, Oulu, Finland
| | - Laura Gough
- Department of Biological Sciences, Towson University, Towson, MD, 21252, USA
| | - Anke Jentsch
- Department of Disturbance Ecology, University of Bayreuth, D-95440, Bayreuth, Germany
| | - Christel Kern
- Northern Research Station, US Forest Service, 5985 Highway K, Rhinelander, WI, 54501, USA
| | - Kari Klanderud
- Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, P.O. Box 5003, NO-1432, Aas, Norway
| | - Alan K Knapp
- Department of Biology, Graduate Degree Program in Ecology, Colorado State University, Fort Collins, CO, 80523, USA
| | - Juergen Kreyling
- Institute of Botany and Landscape Ecology, Experimental Plant Ecology, Greifswald University, Soldmannstrasse 15, D-17487, Greifswald, Germany
| | - Yiqi Luo
- Department of Microbiology and Plant Biology, University of Oklahoma, 770 Van Vleet Oval, Norman, OK, 73019, USA.,Department of Biological Sciences, Center for Ecosystem Science and Society (Ecoss), Northern Arizona University, Flagstaff, AZ, 86011, USA.,Department for Earth System Science, Tsinghua University, Beijing, China
| | - Jennie R McLaren
- Department of Biological Sciences, University of Texas at El Paso, El Paso, TX, 79968, USA
| | - Patrick Megonigal
- Smithsonian Environmental Research Center, Edgewater, MD, 20754, USA
| | - Vladimir Onipchenko
- Department of Geobotany, Moscow State Lomonosov University, Leninskie gory 1-12, 119234, Moscow, Russia
| | - Janet Prevéy
- USFS Pacific Northwest Research Station, 3625 93rd Ave SW, Olympia, WA, 98512, USA
| | - Jodi N Price
- Institute of Land, Water and Society, Charles Sturt University, Albury, NSW, 2640, Australia
| | - Clare H Robinson
- School of Earth & Environmental Sciences, The University of Manchester, Williamson Building, Oxford Road, Manchester, M13 9PL, UK
| | - Osvaldo E Sala
- School of Life Sciences and School of Sustainability, Arizona State University, Tempe, AZ, 85287, USA
| | - Melinda D Smith
- Department of Biology, Graduate Degree Program in Ecology, Colorado State University, Fort Collins, CO, 80523, USA
| | - Nadejda A Soudzilovskaia
- Conservation Biology Department, Institute of Environmental Sciences, CML, Leiden University, Einsteinweg 2, 2333 CC, Leiden, The Netherlands
| | - Lara Souza
- Department of Microbiology and Plant Biology, University of Oklahoma, 770 Van Vleet Oval, Norman, OK, 73019, USA.,Oklahoma Biological Survey, University of Oklahoma, Norman, OK, 73019, USA
| | - David Tilman
- Department of Ecology, Evolution and Behavior, College of Biological Sciences, University of Minnesota, Saint Paul, MN, 55108, USA
| | - Shannon R White
- Environment and Parks, Government of Alberta, Edmonton, AB, T5K 2M4, Canada
| | - Zhuwen Xu
- Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, Liaoning, 110016, China
| | - Laura Yahdjian
- Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura (IFEVA), Facultad de Agronomía, Buenos Aires, Argentina
| | - Qiang Yu
- National Hulunber Grassland Ecosystem Observation and Research Station/Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
| | - Pengfei Zhang
- School of Life Science, Lanzhou University, Lanzhou, Gansu, China
| | - Yunhai Zhang
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China.,Department of Agroecology, Aarhus University, Blichers Allé 20, 8830, Tjele, Denmark
| |
Collapse
|
7
|
Simkin SM, Allen EB, Bowman WD, Clark CM, Belnap J, Brooks ML, Cade BS, Collins SL, Geiser LH, Gilliam FS, Jovan SE, Pardo LH, Schulz BK, Stevens CJ, Suding KN, Throop HL, Waller DM. Conditional vulnerability of plant diversity to atmospheric nitrogen deposition across the United States. Proc Natl Acad Sci U S A 2016; 113:4086-4091. [PMID: 27035943 DOI: 10.5061/dryad.7kn53] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/22/2023] Open
Abstract
Atmospheric nitrogen (N) deposition has been shown to decrease plant species richness along regional deposition gradients in Europe and in experimental manipulations. However, the general response of species richness to N deposition across different vegetation types, soil conditions, and climates remains largely unknown even though responses may be contingent on these environmental factors. We assessed the effect of N deposition on herbaceous richness for 15,136 forest, woodland, shrubland, and grassland sites across the continental United States, to address how edaphic and climatic conditions altered vulnerability to this stressor. In our dataset, with N deposition ranging from 1 to 19 kg N⋅ha(-1)⋅y(-1), we found a unimodal relationship; richness increased at low deposition levels and decreased above 8.7 and 13.4 kg N⋅ha(-1)⋅y(-1) in open and closed-canopy vegetation, respectively. N deposition exceeded critical loads for loss of plant species richness in 24% of 15,136 sites examined nationwide. There were negative relationships between species richness and N deposition in 36% of 44 community gradients. Vulnerability to N deposition was consistently higher in more acidic soils whereas the moderating roles of temperature and precipitation varied across scales. We demonstrate here that negative relationships between N deposition and species richness are common, albeit not universal, and that fine-scale processes can moderate vegetation responses to N deposition. Our results highlight the importance of contingent factors when estimating ecosystem vulnerability to N deposition and suggest that N deposition is affecting species richness in forested and nonforested systems across much of the continental United States.
Collapse
Affiliation(s)
- Samuel M Simkin
- Institute of Arctic and Alpine Research and Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO 80309;
| | - Edith B Allen
- Department of Botany and Plant Sciences, University of California, Riverside, CA 92521; Center for Conservation Biology, University of California, Riverside, CA 92521
| | - William D Bowman
- Institute of Arctic and Alpine Research and Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO 80309
| | - Christopher M Clark
- National Center for Environmental Assessment, United States Environmental Protection Agency, Washington, DC 20460
| | - Jayne Belnap
- Southwest Biological Science Center, United States Geological Survey, Moab, UT 84532
| | - Matthew L Brooks
- Western Ecological Research Center, United States Geological Survey, Oakhurst, CA 93644
| | - Brian S Cade
- Fort Collins Science Center, United States Geological Survey, Fort Collins, CO 80226
| | - Scott L Collins
- Department of Biology, University of New Mexico, Albuquerque, NM 87131
| | - Linda H Geiser
- Pacific Northwest Region Air Resource Management Program, United States Department of Agriculture Forest Service, Corvallis, OR 97339
| | - Frank S Gilliam
- Department of Biological Sciences, Marshall University, Huntington, WV 25755
| | - Sarah E Jovan
- Forest Inventory and Analysis Program, United States Department of Agriculture Forest Service, Portland, OR 97339
| | - Linda H Pardo
- Northern Research Station, United States Department of Agriculture Forest Service, Burlington, VT 05405
| | - Bethany K Schulz
- Forest Inventory and Analysis Program, United States Department of Agriculture Forest Service, Anchorage, AK 99501
| | - Carly J Stevens
- Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, United Kingdom
| | - Katharine N Suding
- Institute of Arctic and Alpine Research and Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO 80309
| | - Heather L Throop
- School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287; School of Life Sciences, Arizona State University, Tempe, AZ 85287
| | - Donald M Waller
- Department of Botany, University of Wisconsin, Madison, WI 53706
| |
Collapse
|
8
|
Simkin SM, Allen EB, Bowman WD, Clark CM, Belnap J, Brooks ML, Cade BS, Collins SL, Geiser LH, Gilliam FS, Jovan SE, Pardo LH, Schulz BK, Stevens CJ, Suding KN, Throop HL, Waller DM. Conditional vulnerability of plant diversity to atmospheric nitrogen deposition across the United States. Proc Natl Acad Sci U S A 2016; 113:4086-91. [PMID: 27035943 PMCID: PMC4839424 DOI: 10.1073/pnas.1515241113] [Citation(s) in RCA: 145] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Atmospheric nitrogen (N) deposition has been shown to decrease plant species richness along regional deposition gradients in Europe and in experimental manipulations. However, the general response of species richness to N deposition across different vegetation types, soil conditions, and climates remains largely unknown even though responses may be contingent on these environmental factors. We assessed the effect of N deposition on herbaceous richness for 15,136 forest, woodland, shrubland, and grassland sites across the continental United States, to address how edaphic and climatic conditions altered vulnerability to this stressor. In our dataset, with N deposition ranging from 1 to 19 kg N⋅ha(-1)⋅y(-1), we found a unimodal relationship; richness increased at low deposition levels and decreased above 8.7 and 13.4 kg N⋅ha(-1)⋅y(-1) in open and closed-canopy vegetation, respectively. N deposition exceeded critical loads for loss of plant species richness in 24% of 15,136 sites examined nationwide. There were negative relationships between species richness and N deposition in 36% of 44 community gradients. Vulnerability to N deposition was consistently higher in more acidic soils whereas the moderating roles of temperature and precipitation varied across scales. We demonstrate here that negative relationships between N deposition and species richness are common, albeit not universal, and that fine-scale processes can moderate vegetation responses to N deposition. Our results highlight the importance of contingent factors when estimating ecosystem vulnerability to N deposition and suggest that N deposition is affecting species richness in forested and nonforested systems across much of the continental United States.
Collapse
Affiliation(s)
- Samuel M Simkin
- Institute of Arctic and Alpine Research and Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO 80309;
| | - Edith B Allen
- Department of Botany and Plant Sciences, University of California, Riverside, CA 92521; Center for Conservation Biology, University of California, Riverside, CA 92521
| | - William D Bowman
- Institute of Arctic and Alpine Research and Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO 80309
| | - Christopher M Clark
- National Center for Environmental Assessment, United States Environmental Protection Agency, Washington, DC 20460
| | - Jayne Belnap
- Southwest Biological Science Center, United States Geological Survey, Moab, UT 84532
| | - Matthew L Brooks
- Western Ecological Research Center, United States Geological Survey, Oakhurst, CA 93644
| | - Brian S Cade
- Fort Collins Science Center, United States Geological Survey, Fort Collins, CO 80226
| | - Scott L Collins
- Department of Biology, University of New Mexico, Albuquerque, NM 87131
| | - Linda H Geiser
- Pacific Northwest Region Air Resource Management Program, United States Department of Agriculture Forest Service, Corvallis, OR 97339
| | - Frank S Gilliam
- Department of Biological Sciences, Marshall University, Huntington, WV 25755
| | - Sarah E Jovan
- Forest Inventory and Analysis Program, United States Department of Agriculture Forest Service, Portland, OR 97339
| | - Linda H Pardo
- Northern Research Station, United States Department of Agriculture Forest Service, Burlington, VT 05405
| | - Bethany K Schulz
- Forest Inventory and Analysis Program, United States Department of Agriculture Forest Service, Anchorage, AK 99501
| | - Carly J Stevens
- Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, United Kingdom
| | - Katharine N Suding
- Institute of Arctic and Alpine Research and Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO 80309
| | - Heather L Throop
- School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287; School of Life Sciences, Arizona State University, Tempe, AZ 85287
| | - Donald M Waller
- Department of Botany, University of Wisconsin, Madison, WI 53706
| |
Collapse
|
9
|
Hinckley ELS, Anderson SP, Baron JS, Blanken PD, Bonan GB, Bowman WD, Elmendorf SC, Fierer N, Fox AM, Goodman KJ, Jones KD, Lombardozzi DL, Lunch CK, Neff JC, SanClements MD, Suding KN, Wieder WR. Optimizing Available Network Resources to Address Questions in Environmental Biogeochemistry. Bioscience 2016. [DOI: 10.1093/biosci/biw005] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
10
|
Ferrenberg S, Knelman JE, Jones JM, Beals SC, Bowman WD, Nemergut DR. Soil bacterial community structure remains stable over a 5-year chronosequence of insect-induced tree mortality. Front Microbiol 2014; 5:681. [PMID: 25566204 PMCID: PMC4267275 DOI: 10.3389/fmicb.2014.00681] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Accepted: 11/20/2014] [Indexed: 12/20/2022] Open
Abstract
Extensive tree mortality from insect epidemics has raised concern over possible effects on soil biogeochemical processes. Yet despite the importance of microbes in nutrient cycling, how soil bacterial communities respond to insect-induced tree mortality is largely unknown. We examined soil bacterial community structure (via 16S rRNA gene pyrosequencing) and community assembly processes (via null deviation analysis) along a 5-year chronosequence (substituting space for time) of bark beetle-induced tree mortality in the southern Rocky Mountains, USA. We also measured microbial biomass and soil chemistry, and used in situ experiments to assess inorganic nitrogen mineralization rates. We found that bacterial community structure and assembly-which was strongly influenced by stochastic processes-were largely unaffected by tree mortality despite increased soil ammonium ([Formula: see text]) pools and reductions in soil nitrate ([Formula: see text]) pools and net nitrogen mineralization rates after tree mortality. Linear models suggested that microbial biomass and bacterial phylogenetic diversity are significantly correlated with nitrogen mineralization rates of this forested ecosystem. However, given the overall resistance of the bacterial community to disturbance from tree mortality, soil nitrogen processes likely remained relatively stable following tree mortality when considered at larger spatial and longer temporal scales-a supposition supported by the majority of available studies regarding biogeochemical effects of bark beetle infestations in this region. Our results suggest that soil bacterial community resistance to disturbance helps to explain the relatively weak effects of insect-induced tree mortality on soil N and C pools reported across the Rocky Mountains, USA.
Collapse
Affiliation(s)
- Scott Ferrenberg
- Department of Ecology and Evolutionary Biology, University of ColoradoBoulder, CO, USA
| | - Joseph E. Knelman
- Department of Ecology and Evolutionary Biology, University of ColoradoBoulder, CO, USA
- Institute of Arctic and Alpine Research, University of ColoradoBoulder, CO, USA
| | | | - Stower C. Beals
- Department of Ecology and Evolutionary Biology, University of ColoradoBoulder, CO, USA
- Institute of Arctic and Alpine Research, University of ColoradoBoulder, CO, USA
| | - William D. Bowman
- Department of Ecology and Evolutionary Biology, University of ColoradoBoulder, CO, USA
- Institute of Arctic and Alpine Research, University of ColoradoBoulder, CO, USA
| | - Diana R. Nemergut
- Institute of Arctic and Alpine Research, University of ColoradoBoulder, CO, USA
- Department of Biology, Duke UniversityDurham, NC, USA
| |
Collapse
|
11
|
McDonnell TC, Belyazid S, Sullivan TJ, Sverdrup H, Bowman WD, Porter EM. Modeled subalpine plant community response to climate change and atmospheric nitrogen deposition in Rocky Mountain National Park, USA. Environ Pollut 2014; 187:55-64. [PMID: 24448482 DOI: 10.1016/j.envpol.2013.12.021] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Revised: 12/20/2013] [Accepted: 12/22/2013] [Indexed: 05/20/2023]
Abstract
To evaluate potential long-term effects of climate change and atmospheric nitrogen (N) deposition on subalpine ecosystems, the coupled biogeochemical and vegetation community competition model ForSAFE-Veg was applied to a site at the Loch Vale watershed of Rocky Mountain National Park, Colorado. Changes in climate and N deposition since 1900 resulted in pronounced changes in simulated plant species cover as compared with ambient and estimated future community composition. The estimated critical load (CL) of N deposition to protect against an average future (2010-2100) change in biodiversity of 10% was between 1.9 and 3.5 kg N ha(-1) yr(-1). Results suggest that the CL has been exceeded and vegetation at the study site has already undergone a change of more than 10% as a result of N deposition. Future increases in air temperature are forecast to cause further changes in plant community composition, exacerbating changes in response to N deposition alone.
Collapse
Affiliation(s)
- T C McDonnell
- E&S Environmental Chemistry Inc., P.O. Box 609, Corvallis, OR 97339, USA.
| | - S Belyazid
- Belyazid Consulting & Communication AB, Stationsvägen 13, 517 34 Bollebygd, Sweden.
| | - T J Sullivan
- E&S Environmental Chemistry Inc., P.O. Box 609, Corvallis, OR 97339, USA.
| | - H Sverdrup
- Biogeochemistry and Systems Analysis, Chemical Engineering, Lund University, SE-221 00 Lund, Sweden.
| | - W D Bowman
- Ecology and Evolutionary Biology, University of Colorado, Boulder, CO 80309, USA.
| | - E M Porter
- National Park Service, Air Resources Division, Denver, CO 80225, USA.
| |
Collapse
|
12
|
Spasojevic MJ, Bowman WD, Humphries HC, Seastedt TR, Suding KN. Changes in alpine vegetation over 21 years: Are patterns across a heterogeneous landscape consistent with predictions? Ecosphere 2013. [DOI: 10.1890/es13-00133.1] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
|
13
|
Bowman WD, Murgel J, Blett T, Porter E. Nitrogen critical loads for alpine vegetation and soils in Rocky Mountain National Park. J Environ Manage 2012; 103:165-171. [PMID: 22516810 DOI: 10.1016/j.jenvman.2012.03.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2011] [Revised: 12/27/2011] [Accepted: 03/02/2012] [Indexed: 05/31/2023]
Abstract
We evaluated the ecological thresholds associated with vegetation and soil responses to nitrogen (N) deposition, by adding NH(4)NO(3) in solution at rates of 5, 10 and 30 kg N ha(-1) yr(-1) to plots in a species rich dry meadow alpine community in Rocky Mountain National Park receiving ambient N deposition of 4 kg N ha(-1) yr(-1). To determine the levels of N input that elicited changes, we measured plant species composition annually, and performed one-time measurements of aboveground biomass and N concentrations, soil solution and resin bag inorganic N, soil pH, and soil extractable cations after 3 years of N additions. Our goal was to use these dose-response relationships to provide N critical loads for vegetation and soils for the alpine in Rocky Mountain National Park. Species richness and diversity did not change in response to the treatments, but one indicator species, Carex rupestris increased in cover from 34 to 125% in response to the treatments. Using the rate of change in cover for C. rupestris in the treatment and the ambient plots, and assuming the change in cover was due solely to N deposition, we estimated a N critical load for vegetation at 3 kg N ha(-1) yr(-1). Inorganic N concentrations in soil solution increased above ambient levels at input rates between 9 kg N ha(-1) yr(-1) (resin bags) and 14 kg N ha(-1) yr(-1) (lysimeters), indicating biotic and abiotic sinks for N deposition are exhausted at these levels. No changes in soil pH or extractable cations occurred in the treatment plots, indicating acidification had not occurred after 3 years. We conclude that N critical loads under 10 kg ha(-1) yr(-1) are needed to prevent future acidification of soils and surface waters, and recommend N critical loads for vegetation at 3 kg N ha(-1) yr(-1) as important for protecting natural plant communities and ecosystem services in Rocky Mountain National Park.
Collapse
Affiliation(s)
- William D Bowman
- Mountain Research Station, Institute of Arctic and Alpine Research, University of Colorado, Boulder, CO 80309, USA.
| | | | | | | |
Collapse
|
14
|
Ashton IW, Miller AE, Bowman WD, Suding KN. Niche complementarity due to plasticity in resource use: plant partitioning of chemical N forms. Ecology 2010; 91:3252-60. [DOI: 10.1890/09-1849.1] [Citation(s) in RCA: 253] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
|
15
|
Nemergut DR, Townsend AR, Sattin SR, Freeman KR, Fierer N, Neff JC, Bowman WD, Schadt CW, Weintraub MN, Schmidt SK. The effects of chronic nitrogen fertilization on alpine tundra soil microbial communities: implications for carbon and nitrogen cycling. Environ Microbiol 2008; 10:3093-105. [PMID: 18764871 DOI: 10.1111/j.1462-2920.2008.01735.x] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Diana R Nemergut
- Institute of Arctic and Alpine Research, Environmental Studies Program, University of Colorado, Boulder, Colorado, USA.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
16
|
Meier CL, Bowman WD. Phenolic-rich leaf carbon fractions differentially influence microbial respiration and plant growth. Oecologia 2008; 158:95-107. [PMID: 18704503 DOI: 10.1007/s00442-008-1124-9] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2007] [Accepted: 07/24/2008] [Indexed: 11/24/2022]
Abstract
Phenolics can reduce soil nutrient availability, either indirectly by stimulating microbial nitrogen (N) immobilization or directly by enhancing physical protection within soil. Phenolic-rich plants may therefore negatively affect neighboring plant growth by restricting the N supply. We used a slow-growing, phenolic-rich alpine forb, Acomastylis rossii, to test the hypothesis that phenolic-rich carbon (C) fractions stimulate microbial population growth and reduce plant growth. We generated low-molecular-weight (LMW) fractions, tannin fractions, and total soluble C fractions from A. rossii and measured their effects on soil respiration and growth of Deschampsia caespitosa, a fast-growing, co-dominant grass. Fraction effects fell into two distinct categories: (1) fractions did not increase soil respiration and killed D. caespitosa plants, or (2) fractions stimulated soil respiration and reduced plant growth and plant N concentration while simultaneously inhibiting root growth. The LMW phenolic-rich fractions increased soil respiration and reduced plant growth more than tannins. These results suggest that phenolic compounds can inhibit root growth directly as well as indirectly affect growth by reducing pools of plant available N by stimulating soil microbes. Both mechanisms illustrate how below-ground phenolic effects may influence the growth of neighboring plants. We also examined patterns of foliar phenolic concentrations among populations of A. rossii across a natural productivity gradient (productivity was used as a proxy for competition intensity). Concentrations of some LMW phenolics increased significantly in more productive sites where A. rossii is a competitive equal with the faster growing D. caespitosa. Taken together, our results contribute important information to the growing body of evidence indicating that the quality of C moving from plants to soils can have significant effects on neighboring plant performance, potentially associated with phytoxic effects, and indirect effects on soil biogeochemistry.
Collapse
Affiliation(s)
- Courtney L Meier
- Department of Ecology and Evolutionary Biology and Mountain Research Station, Institute of Arctic and Alpine Research, University of Colorado at Boulder, Boulder, CO, 80309-0334, USA.
| | | |
Collapse
|
17
|
Suding KN, Ashton IW, Bechtold H, Bowman WD, Mobley ML, Winkleman R. PLANT AND MICROBE CONTRIBUTION TO COMMUNITY RESILIENCE IN A DIRECTIONALLY CHANGING ENVIRONMENT. ECOL MONOGR 2008. [DOI: 10.1890/07-1092.1] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
|
18
|
Cleland EE, Clark CM, Collins SL, Fargione JE, Gough L, Gross KL, Milchunas DG, Pennings SC, Bowman WD, Burke IC, Lauenroth WK, Robertson GP, Simpson JC, Tilman D, Suding KN. SPECIES RESPONSES TO NITROGEN FERTILIZATION IN HERBACEOUS PLANT COMMUNITIES, AND ASSOCIATED SPECIES TRAITSEcological ArchivesE089-070. Ecology 2008. [DOI: 10.1890/07-1104.1] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
|
19
|
Ashton IW, Miller AE, Bowman WD, Suding KN. Nitrogen preferences and plant-soil feedbacks as influenced by neighbors in the alpine tundra. Oecologia 2008; 156:625-36. [PMID: 18347816 DOI: 10.1007/s00442-008-1006-1] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2006] [Accepted: 02/11/2008] [Indexed: 11/28/2022]
Abstract
Plant resource partitioning of chemical forms of nitrogen (N) may be an important factor promoting species coexistence in N-limited ecosystems. Since the microbial community regulates N-form transformations, plant partitioning of N may be related to plant-soil feedbacks. We conducted a (15)N tracer addition experiment to study the ability of two alpine plant species, Acomastylis rossii and Deschampsia caespitosa, to partition organic and inorganic forms of N. The species are codominant and associated with strong plant-soil feedbacks that affect N cycling. We manipulated interspecific interactions by removing Acomastylis or Deschampsia from areas where the species were codominant to test if N uptake patterns varied in the presence of the other species. We found that Deschampsia acquired organic and inorganic N more rapidly than Acomastylis, regardless of neighbor treatment. Plant N uptake-specifically ammonium uptake-increased with plant density and the presence of an interspecific neighbor. Interestingly, this change in N uptake was not in the expected direction to reduce niche overlap and instead suggested facilitation of ammonium use. To test if N acquisition patterns were consistent with plant-soil feedbacks, we also compared microbial rhizosphere extracellular enzyme activity in patches dominated by one or the other species and in areas where they grew together. The presence of both species was generally associated with increased rhizosphere extracellular enzyme activity (five of ten enzymes) and a trend towards increased foliar N concentrations. Taken together, these results suggest that feedbacks through the microbial community, either in response to increased plant density or specific plant neighbors, could facilitate coexistence. However, coexistence is promoted via enhanced resource uptake rather than reduced niche overlap. The importance of resource partitioning to reduce the intensity of competitive interactions might vary across systems, particularly as a function of plant-soil feedbacks.
Collapse
Affiliation(s)
- I W Ashton
- Department of Ecology and Evolutionary Biology, University of California, Irvine, Irvine, CA 92697-2525, USA.
| | | | | | | |
Collapse
|
20
|
Abstract
The importance of interspecific competition as a cause of resource partitioning among species has been widely assumed but rarely tested. Using neighbor removals in combination with 15N tracer additions in the field, we examined variation among three alpine species in the uptake of 15N-NH4+, 15N-NO3-, and 15N-13C-[2]-glycine in intact neighborhoods, when paired with a specific neighbor, and when all neighbors were removed. Species varied in the capacity to take up 15N-labeled NH4+, NO3-, and glycine in intact neighborhoods and in interspecific pairs. When interspecific neighbor pairs were compared with no neighbor controls, neighbors reduced 15N uptake in target species by as much as 50%, indicating competition for N. Furthermore, neighbor identity influenced the capacity of species to take up different forms of N. Thus, competition within interspecific neighbor pairs often caused reduced uptake of a particular form of N, as well as shifts to uptake of an alternative form of N. Such shifts in resource use as a result of competition are an implicit assumption in studies of resource partitioning but have rarely been documented. Our study suggests that plasticity in the uptake of different forms of N may be a mechanism by which cooccurring plants reduce competition for N.
Collapse
Affiliation(s)
- Amy E Miller
- Mountain Research Station, Institute of Arctic and Alpine Research, and Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, Colorado 80309, USA.
| | | | | |
Collapse
|
21
|
Abstract
Increases in the deposition of anthropogenic nitrogen (N) have been linked to several terrestrial ecological changes, including soil biogeochemistry, plant stress susceptibility, and community diversity. Recognizing the need to identify sensitive indicators of biotic response to N deposition, we empirically estimated the N critical load for changes in alpine plant community composition and compared this with the estimated critical load for soil indicators of ecological change. We also measured the degree to which alpine vegetation may serve as a sink for anthropogenic N and how much plant sequestration is related to changes in species composition. We addressed these research goals by adding 20, 40, or 60 kg N x ha(-1) x yr(-1), along with an ambient control (6 kg N x ha(-1) x yr(-1) total deposition), to a species-rich alpine dry meadow for an eight-year period. Change in plant species composition associated with the treatments occurred within three years of the initiation of the experiment and were significant at all levels of N addition. Using individual species abundance changes and ordination scores, we estimated the N critical loads (total deposition) for (1) change in individual species to be 4 kg N x ha(-1) yr(-1) and (2) for overall community change to be 10 kg N x ha(-1) x yr(-1). In contrast, increases in NO3- leaching, soil solution inorganic NO3-, and net N nitrification occurred at levels above 20 kg N x ha(-1) x yr(-1). Increases in total aboveground biomass were modest and transient, occurring in only one of the three years measured. Vegetative uptake of N increased significantly, primarily as a result of increasing tissue N concentrations and biomass increases in subdominant species. Aboveground vegetative uptake of N accounted for <40% of the N added. The results of this experiment indicate that changes in vegetation composition will precede detectable changes in more traditionally used soil indicators of ecosystem responses to N deposition and that changes in species composition are probably ongoing in alpine dry meadows of the Front Range of the Colorado Rocky Mountains. Feedbacks to soil N cycling associated with changes in litter quality and species composition may result in only short-term increases in vegetation N pools.
Collapse
Affiliation(s)
- William D Bowman
- Mountain Research Station, Institute of Arctic and Alpine Research, and Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, Colorado 80309-0334, USA.
| | | | | | | |
Collapse
|
22
|
Suding KN, Miller AE, Bechtold H, Bowman WD. The consequence of species loss on ecosystem nitrogen cycling depends on community compensation. Oecologia 2006; 149:141-9. [PMID: 16609872 DOI: 10.1007/s00442-006-0421-4] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2005] [Accepted: 03/17/2006] [Indexed: 11/28/2022]
Abstract
Repercussions of species loss on ecosystem processes depend on the effects of the lost species as well as the compensatory responses of the remaining species in the community. We experimentally removed two co-dominant plant species and added a 15N tracer in alpine tundra to compare how species' functional differences influence community structure and N cycling. For both of the species, production compensated for the biomass removed by the second year. However, the responses of the remaining species depended on which species was removed. These differences in compensation influenced how species loss impacted ecosystem processes. After the removal of one of the co-dominant species, Acomastylis rossii, there were few changes in the relative abundance of the remaining species, and differences in functioning could be predicted based on effects associated with the removed species. In contrast, the removal of the other co-dominant, Deschampsia caespitosa, was associated with subsequent changes in community structure (species relative abundances and diversity) and impacts on ecosystem properties (microbial biomass N, dissolved organic N, and N uptake of subordinate species). Variation in compensation may contribute to the resulting effects on ecosystem functioning, with the potential to buffer or accelerate the effects of species loss.
Collapse
Affiliation(s)
- Katharine Nash Suding
- Department of Ecology and Evolutionary Biology, University of California, Irvine, CA 92697-2525, USA.
| | | | | | | |
Collapse
|
23
|
Bardgett RD, Bowman WD, Kaufmann R, Schmidt SK. A temporal approach to linking aboveground and belowground ecology. Trends Ecol Evol 2005; 20:634-41. [PMID: 16701447 DOI: 10.1016/j.tree.2005.08.005] [Citation(s) in RCA: 256] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2005] [Revised: 07/27/2005] [Accepted: 08/12/2005] [Indexed: 10/25/2022]
Abstract
Ecologists are becoming increasingly aware of the role of aboveground-belowground relationships in controlling ecosystem processes and properties. Here, we review recent studies that show that relationships between aboveground and belowground communities operate over a hierarchy of temporal scales, ranging from days to seasons, to millennia, with differing consequences for ecosystem structure and function. We propose that a temporal framework is crucial to our understanding of the nature and ecological significance of relationships between aboveground and belowground communities.
Collapse
Affiliation(s)
- Richard D Bardgett
- Institute of Environmental and Natural Sciences, Soil and Ecosystem Ecology Laboratory, Lancaster University, Lancaster, UK, LA1 4YQ.
| | | | | | | |
Collapse
|
24
|
Bowman WD, Steltzer H, Rosenstiel TN, Cleveland CC, Meier CL. Litter effects of two co-occurring alpine species on plant growth, microbial activity and immobilization of nitrogen. OIKOS 2004. [DOI: 10.1111/j.0030-1299.2004.12721.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
25
|
|
26
|
Neff JC, Townsend AR, Gleixner G, Lehman SJ, Turnbull J, Bowman WD. Variable effects of nitrogen additions on the stability and turnover of soil carbon. Nature 2002; 419:915-7. [PMID: 12410307 DOI: 10.1038/nature01136] [Citation(s) in RCA: 586] [Impact Index Per Article: 26.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2002] [Accepted: 09/12/2002] [Indexed: 11/09/2022]
Abstract
Soils contain the largest near-surface reservoir of terrestrial carbon and so knowledge of the factors controlling soil carbon storage and turnover is essential for understanding the changing global carbon cycle. The influence of climate on decomposition of soil carbon has been well documented, but there remains considerable uncertainty in the potential response of soil carbon dynamics to the rapid global increase in reactive nitrogen (coming largely from agricultural fertilizers and fossil fuel combustion). Here, using 14C, 13C and compound-specific analyses of soil carbon from long-term nitrogen fertilization plots, we show that nitrogen additions significantly accelerate decomposition of light soil carbon fractions (with decadal turnover times) while further stabilizing soil carbon compounds in heavier, mineral-associated fractions (with multidecadal to century lifetimes). Despite these changes in the dynamics of different soil pools, we observed no significant changes in bulk soil carbon, highlighting a limitation inherent to the still widely used single-pool approach to investigating soil carbon responses to changing environmental conditions. It remains to be seen if the effects observed here-caused by relatively high, short-term fertilizer additions-are similar to those arising from lower, long-term additions of nitrogen to natural ecosystems from atmospheric deposition, but our results suggest nonetheless that current models of terrestrial carbon cycling do not contain the mechanisms needed to capture the complex relationship between nitrogen availability and soil carbon storage.
Collapse
Affiliation(s)
- Jason C Neff
- Earth Surface Processes Team, Geologic Division, US Geological Survey, MS 980, Denver Federal Center, Denver, Colorado 80225, USA.
| | | | | | | | | | | |
Collapse
|
27
|
|
28
|
|
29
|
Steltzer H, Bowman WD. Original Articles: Differential Influence of Plant Species on Soil Nitrogen Transformations Within Moist Meadow Alpine Tundra. Ecosystems 1998. [DOI: 10.1007/s100219900042] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
30
|
Reich PB, Walters MB, Ellsworth DS, Vose JM, Volin JC, Gresham C, Bowman WD. Relationships of leaf dark respiration to leaf nitrogen, specific leaf area and leaf life-span: a test across biomes and functional groups. Oecologia 1998; 114:471-482. [PMID: 28307896 DOI: 10.1007/s004420050471] [Citation(s) in RCA: 186] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Based on prior evidence of coordinated multiple leaf trait scaling, we hypothesized that variation among species in leaf dark respiration rate (R d) should scale with variation in traits such as leaf nitrogen (N), leaf life-span, specific leaf area (SLA), and net photosynthetic capacity (A max). However, it is not known whether such scaling, if it exists, is similar among disparate biomes and plant functional types. We tested this idea by examining the interspecific relationships between R d measured at a standard temperature and leaf life-span, N, SLA and A max for 69 species from four functional groups (forbs, broad-leafed trees and shrubs, and needle-leafed conifers) in six biomes traversing the Americas: alpine tundra/subalpine forest, Colorado; cold temperate forest/grassland, Wisconsin; cool temperate forest, North Carolina; desert/shrubland, New Mexico; subtropical forest, South Carolina; and tropical rain forest, Amazonas, Venezuela. Area-based R d was positively related to area-based leaf N within functional groups and for all species pooled, but not when comparing among species within any site. At all sites, mass-based R d (R d-mass) decreased sharply with increasing leaf life-span and was positively related to SLA and mass-based A max and leaf N (leaf N mass). These intra-biome relationships were similar in shape and slope among sites, where in each case we compared species belonging to different plant functional groups. Significant R d-mass-N mass relationships were observed in all functional groups (pooled across sites), but the relationships differed, with higher R d at any given leaf N in functional groups (such as forbs) with higher SLA and shorter leaf life-span. Regardless of biome or functional group, R d-mass was well predicted by all combinations of leaf life-span, N mass and/or SLA (r 2≥ 0.79, P < 0.0001). At any given SLA, R d-mass rises with increasing N mass and/or decreasing leaf life-span; and at any level of N mass, R d-mass rises with increasing SLA and/or decreasing leaf life-span. The relationships between R d and leaf traits observed in this study support the idea of a global set of predictable interrelationships between key leaf morphological, chemical and metabolic traits.
Collapse
Affiliation(s)
- Peter B Reich
- Department of Forest Resources, University of Minnesota, St. Paul, MN 55108, USA Fax 612-625-5212; e-mail: , , , , , , US
| | - Michael B Walters
- Faculty of Natural Resources and Environmental Studies, University of Northern British Columbia, Prince George, BC, Canada V2N 4Z9, , , , , , CA
| | - David S Ellsworth
- Department of Applied Science, Brookhaven National Laboratory, Upton, NY 11973, USA, , , , , , US
| | - James M Vose
- U.S. Forest Service, Coweeta Hydrological Lab., Otto, NC 28763, USA, , , , , , US
| | - John C Volin
- Division of Science, Florida Atlantic University, Davie, FL 33314, USA, , , , , , US
| | - Charles Gresham
- Baruch Forest Institute, Clemson University, Georgetown, SC 29442, USA, , , , , , US
| | - William D Bowman
- Mountain Research Station, Institute of Arctic and Alpine Research, and Department of EPO Biology, University of Colorado, Boulder, CO 80309, USA, , , , , , US
| |
Collapse
|
31
|
|
32
|
|
33
|
Bowman WD, Knight DH. Mountains and Plains: The Ecology of Wyoming Landscapes. Ecology 1997. [DOI: 10.2307/2266157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
34
|
Theodose TA, Bowman WD. The Influence of Interspecific Competition on the Distribution of an Alpine Graminoid: Evidence for the Importance of Plant Competition in an Extreme Environment. OIKOS 1997. [DOI: 10.2307/3546095] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
35
|
Bowman WD, Schardt JC, Schmidt SK. Symbiotic N 2-fixation in alpine tundra: ecosystem input and variation in fixation rates among communities. Oecologia 1996. [PMID: 28307848 DOI: 10.1007/bf003x34660] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Annual inputs of symbiotic N2-fixation associated with 3 species of alpine Trifolium were estimated in four alpine communities differing in resource supplies. We hypothesized that fixation rates would vary according to the degree of N, P, and water limitation of production, with the higher rates of fixation in N limited communities (dry meadow, moist meadow) and lower rates in P and water limited communities (wet meadow, fellfield). To estimate N2-fixation rates, natural abundance of N isotopes (δ15N) were measured in field collected Trifolium and reference plants and in Trifolium plants grown in N-free medium in a growth chamber. All three Trifolium species relied on a large proportion of atmospherically-fixed N2 to meet their N requirements, ranging from 70 to 100%. There were no apparent differences in the proportion of plant N derived from fixation among the communities, but differences in the contribution of the Trifolium species to community cover resulted in a wide range of annual N inputs from fixation, from 127 mg m-2 year-1 in wet meadows to 810 mg m-2 year-1 in fellfields. Annual spatially integrated input of symbiotic N2-fixation to Niwot Ridge, Colorado was estimated at 490 mg m-2 year-1 (5 kg ha-1 year-1), which is relatively high in the context of estimates of net N mineralization and N deposition.
Collapse
Affiliation(s)
- William D Bowman
- Mountain Research Station Institute of Arctic and Alpine Research, University of Colorado, 80309-0334, CO, Boulder, USA
- Department of Environmental Population, and Organismic Biology, University of Colorado, 80309-0334, Boulder, CO, USA
| | - James C Schardt
- Department of Environmental Population, and Organismic Biology, University of Colorado, 80309-0334, Boulder, CO, USA
| | - Steven K Schmidt
- Department of Environmental Population, and Organismic Biology, University of Colorado, 80309-0334, Boulder, CO, USA
| |
Collapse
|
36
|
|
37
|
Theodose TA, Jaeger CH, Bowman WD, Schardt JC. Uptake and Allocation of 15 N in Alpine Plants: Implications for the Importance of Competitive Ability in Predicting Community Structure in a Stressful Environment. OIKOS 1996. [DOI: 10.2307/3546321] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
38
|
Wefel JS, Jensen ME, Triolo PT, Faller RV, Hogan MM, Bowman WD. De/remineralization from sodium fluoride dentifrices. Am J Dent 1995; 8:217-20. [PMID: 7576392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
PURPOSE To test the demineralization/remineralization effects of sodium fluoride dentifrices using an in situ single-section crown model system. MATERIALS AND METHODS A fluoride dose response was evaluated using 0, 1100 and 2800 ppm F-, along with the effects of an enhanced fluoride delivery system (polyampholyte-NaF). The single-section crown model was employed with supervised toothbrushing twice a day. At the end of each 1-month study leg, sections were removed and replaced with new sections for the next leg. Both before and after the double-blind, crossover portion of the study, sections were evaluated by polarized light microscopy and microradiography. The change in mineral content of the enamel and root lesions was analyzed by ANOVA with a Waller-Duncan K-Ratio Test post hoc. RESULTS The placebo dentifrice group showed a loss of mineral and was statistically different from all groups. The fluoride dentifrices showed increasing amounts of enamel mineral gain, with increasing fluoride concentration. The polyampholyte-NaF delivery system with 1100 ppm F- was equivalent to the 2800 ppm F- dentifrice. Root lesions gave similar rank-order results although all treatments showed demineralization or mineral loss.
Collapse
Affiliation(s)
- J S Wefel
- Dows Institute for Dental Research, College of Dentistry, University of Iowa, Iowa City 52242, USA
| | | | | | | | | | | |
Collapse
|
39
|
Bowman WD, Theodose TA, Fisk MC. Physiological and production responses of plant growth forms to increases in limiting resources in alpine tundra: implications for differential community response to environmental change. Oecologia 1995; 101:217-227. [DOI: 10.1007/bf00317287] [Citation(s) in RCA: 87] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/1994] [Accepted: 09/13/1994] [Indexed: 11/28/2022]
|
40
|
|
41
|
|
42
|
|
43
|
Abstract
Methods used for the analysis of tooth de- and remineralization include techniques with various degrees of sophistication and quantitative capabilities, ranging from direct measures of mineral gain/loss (e.g., microradiography) to indirect measures (e.g., iodide permeability) of changes in tooth mineral properties. In all instances, the capabilities of methods for accurate determination of changes in tooth mineral properties are affected by procedures used in the preparation of specimens for analysis, the magnitude of change taking place in the test (vs. the detection limits of the techniques), and protocols for specimen analysis. In specific instances, such as in the case of dentin, unique specimen-handling and analysis procedures must be used to prevent artifacts. The choice of techniques for the assessment of de- and remineralization depends strongly upon study protocols and laboratory capabilities; however, 'quantitative' measures of mineral gain and loss are possible only if direct chemical or radiographic techniques are used. Either radiographic, cross-sectioned microhardness or polarized light can be used for the determination of lesion depth. Porosity, light-scattering, and surface microhardness are indirect techniques which complement direct measures of mineral gain and loss. Whatever methods are used in the analysis of de- and remineralization, researchers must take care to differentiate accurately among the quantitative capabilities of techniques used in analysis.
Collapse
Affiliation(s)
- D J White
- Procter & Gamble Company, Sharon Woods Technical Center, Cincinnati, Ohio 45241
| | | | | |
Collapse
|
44
|
Abstract
Isoprene (2-methyl-1,3-butadiene) is one of the major volatile hydrocarbons emitted by plants, but its biosynthetic pathway and role in plant metabolism are unknown. Mucuna sp. (velvet bean) is an isoprene emitter, and leaf isoprene emission rate increased as much as 125-fold as leaves developed, and declined in older leaves. Net CO(2) assimilation and stomatal conductance, under different growth and environmental conditions, increased 3 to 5 days prior to an increase in isoprene emission rate, indicating that photosynthetic competence develops before significant isoprene emission occurs.
Collapse
Affiliation(s)
- J Grinspoon
- Department of Chemistry and Biochemistry, Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado 80309-0215
| | | | | |
Collapse
|
45
|
Bowman WD, Hubick KT, von Caemmerer S, Farquhar GD. Short-term changes in leaf carbon isotope discrimination in salt- and water-stressed c(4) grasses. Plant Physiol 1989; 90:162-6. [PMID: 16666728 PMCID: PMC1061692 DOI: 10.1104/pp.90.1.162] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Online carbon isotope discrimination (Delta) and leaf gas exchange measurements were made with control and salt-stressed Zea mays and Andropogon glomeratus, two NADP-ME type C(4) grasses. Linear relationships between Delta and p(i)/p(a) (the ratio of intercellular to atmospheric CO(2) partial pressure) were found for control plants which agreed well with theoretical models describing carbon isotope discrimination in C(4) plants. These data provided estimates of phi, the proportion of CO(2) fixed by phosphoenolpyruvate carboxylase which leaks out of the bundle sheath and the component of fractionation due to diffusion in air. Salt-stressed plants had wider variation in Delta for the same or less range in p(i)/p(a). Additional work indicated Delta changed independently of p(i)/p(a) in both water- and salt-stressed plants, suggesting a possible diurnal change in phi as plant water status changed linked to a decrease in the activity of the C(3) photosynthetic pathway relative to C(4) pathway activity. The possible effect of stress-induced changes in phi on organic matter delta(13) C of C(4) plants is apt to be most apparent in chronically stressed environments.
Collapse
Affiliation(s)
- W D Bowman
- Plant Environmental Biology Group, Research School of Biological Sciences, The Australian National University, Canberra City A.C.T. 2601, Australia
| | | | | | | |
Collapse
|
46
|
White DJ, Bowman WD, Faller RV, Mobley MJ, Wolfgang RA, Yesinowski JP. 19F MAS-NMR and solution chemical characterization of the reactions of fluoride with hydroxyapatite and powdered enamel. Acta Odontol Scand 1988; 46:375-89. [PMID: 3213446 DOI: 10.3109/00016358809004791] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Solution chemical and 19F magic angle spinning-nuclear magnetic resonance (MAS-NMR) methods have been utilized to study the effects of fluoride dose, fluoridating pH, and mineral surface area on the dynamics of fluoride reactivity with hydroxyapatite and powdered human dental enamel in vitro. Both solution chemical fluoride uptake and NMR measurements demonstrated that the reaction products of ionic fluoride with apatite include mixtures of FAP, FHAP, and CaF2, with increased amounts of CaF2 promoted by increased F concentration or decreased pH. NMR analysis showed FAP or FHAP as a reaction product of fluoride uptake under all conditions, regardless of whether CaF2 was formed, unambiguously demonstrating fluorite as an additive rather than substitute form of F reactivity. pH stat measurements demonstrated the release of OH- during F reactivity with apatites corresponding to ion exchange formation of FAP/FHAP or dissolution/reprecipitation formation of CaF2. Phosphate release into solution accompanied fluoride uptake under all conditions, including regions where ion exchange predominated. Whereas powdered dental enamel demonstrated fluoride uptake behavior similar to that of synthetic apatite, the resulting reaction products differed as analyzed by 19F MAS-NMR.
Collapse
Affiliation(s)
- D J White
- Sharon Woods Technical Center, Procter & Gamble Company, Cincinnati, Ohio 45241
| | | | | | | | | | | |
Collapse
|
47
|
Bowman WD, Wietfeldt JR, Faller RV, Agricola FO, Schemehorn BR, Stookey GK, White DJ. In situ fluoride uptake from NaF dentifrices: dose response and effects of a novel enhanced delivery system. Am J Dent 1988; 1:105-11. [PMID: 3214557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
|
48
|
Bowman WD, Evans MD, Wietfeldt JR, Faller RV, Agricola FO, Schemehorn BR, Stookey GK, Dunipace AJ, White DJ. In situ fluoride uptake from 0.05% neutral NaF mouthrinses: effects of a novel enhanced delivery system. Am J Dent 1988; 1:113-7. [PMID: 3214558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
|
49
|
Bowman WD, Strain BR. Response to long- and short-term salinity in populations of the C4 nonhalophyte Andropogon glomeratus Walter B.S.P. Oecologia 1988; 75:73-77. [DOI: 10.1007/bf00378816] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/1987] [Indexed: 11/29/2022]
|
50
|
Abstract
Andropogon glomeratus is a C4 nonhalophytic grass which exhibits population differentiation for tolerance to short-term salinity exposure. To investigate possible physiological mechanisms whch enable salt-tolerant individuals to survive short-term inundation, gas exchange and water relations parameters were measured before and during a 5-day watering treatment of half-strength synthetic seawater in plants from a tolerant and a non-tolerant population. Photosynthetic recovery was followed for 10 days after the salinity treatment. Photosynthetic CO2 uptake was substantially inhibited in both populations. Stomatal conductances decreased and intercellular CO2 concentrations increased, indicating non-stomatal factors were primarily responsible for the decrease in CO2 uptake. After termination of the salinity treatment photosynthetic capacity increased more rapidly in the tolerant population and reached the pretreatment level after 6 days, whereas the nontolerant population did not recover fully after 10 days. A-Ci curves measured before and after the salinity treatment indicated a decrease in the carboxylation efficiency, and suggested a proportionately greater metabolic inhibition relative to the increase in the stomatal limitation. Osmotic adjustment occurred in a 2-day period in the tolerant population, but there was no change in the osmotic potentials or the water potential at the point of turgor loss in the nontolerant population. Thus short-term salt tolerance in the marsh population is associated with rapid osmotic adjustment and recovcry of photosynthetic capacity shortly after the end of the salinity exposure, rather than maintenance of greater photosynthesis during the salinity treatment.
Collapse
Affiliation(s)
| | - Boyd R Strain
- Department of Botany, Duke University, 27706, Durham, NC, USA
| |
Collapse
|