, Volume 99, Issue 4, pp 275–283 | Cite as

Assessing trophic position from nitrogen isotope ratios: effective calibration against spatially varying baselines

  • Paul Woodcock
  • David P. Edwards
  • Rob J. Newton
  • Felicity A. Edwards
  • Chey Vun Khen
  • Simon H. Bottrell
  • Keith C. Hamer
Original Paper


Nitrogen isotope signatures (δ15N) provide powerful measures of the trophic positions of individuals, populations and communities. Obtaining reliable consumer δ15N values depends upon controlling for spatial variation in plant δ15N values, which form the trophic ‘baseline’. However, recent studies make differing assumptions about the scale over which plant δ15N values vary, and approaches to baseline control differ markedly. We examined spatial variation in the δ15N values of plants and ants sampled from eight 150-m transects in both unlogged and logged rainforests. We then investigated whether ant δ15N values were related to variation in plant δ15N values following baseline correction of ant values at two spatial scales: (1) using ‘local’ means of plants collected from the same transect and (2) using ‘global’ means of plants collected from all transects within each forest type. Plant δ15N baselines varied by the equivalent of one trophic level within each forest type. Correcting ant δ15N values using global plant means resulted in consumer values that were strongly positively related to the transect baseline, whereas local corrections yielded reliable estimates of consumer trophic positions that were largely independent of transect baselines. These results were consistent at the community level and when three trophically distinct ant subfamilies and eight abundant ant species were considered separately. Our results suggest that assuming baselines do not vary can produce misleading estimates of consumer trophic positions. We therefore emphasise the importance of clearly defining and applying baseline corrections at a scale that accounts for spatial variation in plant δ15N values.


Stable isotope analysis Trophic structure Biogeochemistry Scale-dependence Nitrogen cycling Selective logging 



We thank staff at the Danum Valley Field Centre, especially Bernadus Bala Ola for the identification of plant samples; Adam, Dedy Mustapha and Anthony Karolus for the fieldwork assistance and Glen Reynolds and Apech Karolus for the logistical support and advice. Tom Fayle, Noel Tawatao and Sukarman Sukimin helped with ant identification, and Elly van der Linde assisted with sample preparation and isotope analysis. We thank Yayasan Sabah, the Danum Valley Management Committee, the State Secretary, Sabah Chief Minister’s Department and the Prime Minister’s Department (EPU) for the permission to conduct the research. This study is part of the Royal Society’s Southeast Asia Rainforest Research Programme (Project No. RS266). PW was supported by an Earth and Biosphere Institute studentship from the University of Leeds, and the work was supported by a grant from the Leverhulme Trust.

Supplementary material

114_2012_896_MOESM1_ESM.docx (69 kb)
ESM 1 (DOCX 69 kb)


  1. Anderson C, Cabana G (2007) Estimating the trophic position of aquatic consumers in river food webs using stable nitrogen isotopes. J N Am Benthol Soc 26:273–285CrossRefGoogle Scholar
  2. Anderson C, Cabana G (2009) Anthropogenic alterations of lotic food web structure: evidence from use of nitrogen isotopes. Oikos 118:1929–1939CrossRefGoogle Scholar
  3. Bai E, Boutton TW, Liu F, Ben Wu X, Archer SR, Hallmark T (2009) Spatial variation of the stable nitrogen isotope ratio of woody plants along a topoedaphic gradient in a subtropical savannah. Oecologia 159:493–503PubMedCrossRefGoogle Scholar
  4. Ballard TM (2000) Impacts of forest management on northern forest soils. Forest Ecology Manag 133:37–42CrossRefGoogle Scholar
  5. Bearhop S, Adams CE, Waldron S, Fuller RA, MacLeod H (2004) Determining trophic niche width: a novel approach using stable isotope analysis. J Anim Ecol 73:1007–1012CrossRefGoogle Scholar
  6. Bestelmeyer BT, Agosti D, Alonso LE, Brandão CRF, Brown WL Jr, Delabie JCH (2000) Field techniques for the study of ground-dwelling ants: an overview, description and evaluation. In: Agosti D, Maier JD, Alonso LE, Schultz TR (eds) Ants—standard methods for measuring and monitoring biodiversity. Biological diversity handbook series. Smithsonian Institution, Washington DC, pp 122–144Google Scholar
  7. Blüthgen N, Gebauer G, Fiedler K (2003) Disentangling a rainforest food web using stable isotopes: dietary diversity in a species-rich ant community. Oecologia 137:426–435PubMedCrossRefGoogle Scholar
  8. Brown WL Jr (2000) Diversity of ants. In: Agosti D, Maier JD, Alonso LE, Schultz TR (eds) Ants—standard methods for measuring and monitoring biodiversity. Biological diversity handbook series. Smithsonian Institution, Washington DC, pp 45–79Google Scholar
  9. Brühl CA (2001) Leaf litter ant communities in tropical lowland rain forests in Sabah, Malaysia: effects of forest disturbance and fragmentation. PhD Thesis, University of Würzberg, WürzburgGoogle Scholar
  10. Brühl CA, Eltz T, Linsenmair KE (2003) Size does matter—effects of tropical rainforest fragmentation on the leaf litter ant community in Sabah, Malaysia. Biodivers Conserv 12:1371–1389CrossRefGoogle Scholar
  11. Carroll CR, Janzen DH (1973) Ecology of foraging by ants. Ann Rev Ecol Syst 4:231–257CrossRefGoogle Scholar
  12. Cherel Y, Hobson KA, Bailleul F, Groscolas R (2005) Nutrition, physiology and stable isotopes: new information from fasting and molting penguins. Ecology 86:2881–2888CrossRefGoogle Scholar
  13. Coulson J, Bottrell SH, Lee J (2005) Recreating atmospheric sulphur deposition histories from peat stratigraphy: diagenetic conditions required for signal preservation and reconstruction of past sulphur deposition in the Derbyshire Peak District, UK. Chem Geol 218:223–248CrossRefGoogle Scholar
  14. Craine JM, Elmore AJ, Aidar MPM, Bustamante M, Dawson TE, Hobbie EA, Kahmen A, Macks MC, McLauchlan KK, Michelsen A, Nardoto GB, Pardo LH, Peñuelas J, Reich PB, Schuur EAG, Stock WD, Templer PH, Virginia RA, Welker JM, Wright IJ (2009) Global patterns of foliar nitrogen isotopes and their relationships with climate, mycorrhizal fungi, foliar nutrient concentrations, and nitrogen availability. New Phytol 183:980–992PubMedCrossRefGoogle Scholar
  15. Davidson DW, Cook SC, Snelling RR, Chua TH (2003) Explaining the abundance of ants in lowland tropical rainforest canopies. Science 300:969–972PubMedCrossRefGoogle Scholar
  16. Edwards DP, Larsen TH, Docherty TDS, Ansell FA, Hsu WW, Derhé MA, Hamer KC, Wilcove DS (2011) Degraded lands worth protecting: the biological importance of Southeast Asia’s repeatedly logged forests. P Roy Soc B-Biol Sci 278:89–90Google Scholar
  17. Evans RD (2001) Physiological mechanisms influencing plant nitrogen isotope composition. Trends Plant Sci 6:121–126PubMedCrossRefGoogle Scholar
  18. Feldhaar H, Gebauer G, Blüthgen N (2010) Stable isotopes: past and future in exposing secrets of ant nutrition (Hymenoptera: Formicidae). Myrmecol News 13:3–13Google Scholar
  19. Feldpausch TR, Coutoz EG, Rodriguez EG, Pauletto D, Johnson MS, Faheyk TJ, Lehmann J, Riha SJ (2010) Nitrogen aboveground turnover and soil stocks to 8 m depth in primary and selectively logged forest in southern Amazonia. Glob Change Biol 16:1793–1805CrossRefGoogle Scholar
  20. Fisher B, Edwards DP, Giam X, Wilcove DS (2011) The high costs of conserving Southeast Asia’s lowland rainforests. Front Ecol Environ 9:329–334CrossRefGoogle Scholar
  21. Gannes LZ, Martínez del Rio C, Koch P (1997) Natural abundance variation in stable isotopes and their use in animal physiological ecology. Comp Biochem Phys A 119:725–737Google Scholar
  22. Garten CT (1993) Variation in foliar δ15N abundance and the availability of soil nitrogen on Walker Branch watershed. Ecology 74:2098–2113CrossRefGoogle Scholar
  23. Hipfner JM, Charette MR, Blackburn GS (2007) Subcolony variation in breeding success in the tufted puffin (Fratercula cirrhata): association with foraging ecology and implications. Auk 124:1149–1157CrossRefGoogle Scholar
  24. Hobbie EA, Macko SA, Williams M (2000) Correlations between foliar δ15N and nitrogen concentrations may indicate plant-mycorrhizal interactions. Oecologia 122:273–283CrossRefGoogle Scholar
  25. Hogberg P (1997) 15N natural abundance in soil-plant systems. New Phytol 137:179–203CrossRefGoogle Scholar
  26. Lake JL, McKinney RA, Osterman FA, Pruell RJ, Kiddon J, Ryba SA, Libby AD (2001) Stable nitrogen isotopes as indicators of anthropogenic activities in small freshwater systems. Can J Fish Aquat Sci 58:870–878CrossRefGoogle Scholar
  27. Lavoie RA, Champoux L, Rail J-F, Lean DRS (2010) Organochlorines, brominated flame retardants and mercury levels in six seabird species from the Gulf of St. Lawrence (Canada): relationships with feeding ecology, migration and molt. Environ Pollut 158:2189–2199PubMedCrossRefGoogle Scholar
  28. Layman CA, Arrington DA, Montoya CG, Post DM (2007a) Can stable isotope ratios provide for community-wide measures of trophic structure? Ecology 88:42–48PubMedCrossRefGoogle Scholar
  29. Layman CA, Quattrochi JP, Peyer CM, Allgeier JE (2007b) Niche width collapse in a resilient top predator following ecosystem fragmentation. Ecol Lett 10:937–944PubMedCrossRefGoogle Scholar
  30. Lewis OT (2009) Biodiversity change and ecosystem function in tropical forests. Basic Appl Ecol 10:97–102CrossRefGoogle Scholar
  31. Louzao M, Igual JM, Genovart M, Forero MG, Hobson KA, Oro D (2008) Spatial variation in egg size of a top predator: interplay of body size and environmental factors? Acta Oecol 34:186–193CrossRefGoogle Scholar
  32. Marsh CW, Greer AG (1992) Forest land-use in Sabah, Malaysia: an introduction to Danum Valley. Phil Trans Roy Soc B 335:331–339CrossRefGoogle Scholar
  33. Martinez del Rio C, Sabat P, Anderson-Sprecher R, Gonzalez SP (2009) Dietary and isotopic specialisation: the isotopic niche of three Cinclodes ovenbirds. Oecologia 161:149–159CrossRefGoogle Scholar
  34. McCann KS (2007) Protecting biostructure. Nature 446:29PubMedCrossRefGoogle Scholar
  35. McHugh PA, McIntosh AR, Jellyman PG (2010) Dual influences of ecosystem size and food chain length in streams. Ecol Lett 13:881–890PubMedCrossRefGoogle Scholar
  36. Newsome SD, Martinez del Rio C, Bearhop S, Phillips DL (2007) A niche for isotopic ecology. Front Ecol Environ 5:429–436Google Scholar
  37. Nykvist N, Grip H, Sim BL, Malmer A, Wong FK (1994) Nutrient losses in forest plantations in Sabah, Malaysia. Ambio 23:210–215Google Scholar
  38. Phillips RA, Bearhop S, McGill RAR, Dawson DA (2009) Stable isotopes reveal individual variation in migration strategies and habitat preferences in a suite of seabirds during the nonbreeding season. Oecologia 160:795–806PubMedCrossRefGoogle Scholar
  39. Ponsard S, Arditi R (2000) What can δ15N and δ13C tell us about the food webs of soil macro-invertebrates? Ecology 81:852–864Google Scholar
  40. Posada JM, Schuur EAG (2011) Relationships among precipitation regime, nutrient availability and carbon turnover in tropical rain forests. Oecologia 165:783–795PubMedCrossRefGoogle Scholar
  41. Post DM (2002) Using stable isotopes to estimate trophic position: models, methods and assumption. Ecology 83:703–718CrossRefGoogle Scholar
  42. R Development Core Team (2010) R: a language and environment for statistical computing. R Foundation for Statistical Computing, Vienna.
  43. Quevedo M, Svanbäck R, Eklöv P (2009) Intrapopulation niche partitioning in a generalist predator limits food web connectivity. Ecology 90:2263–2274PubMedCrossRefGoogle Scholar
  44. Reich KJ, Bjorndal KA, Martinez del Rio C (2008) Effects of growth and tissue type on the kinetics of 13C and 15N incorporation in a rapidly growing ectotherm. Oecologia 155:651–663PubMedCrossRefGoogle Scholar
  45. Sears J, Hatch SA, O’Brien DM (2009) Disentangling effects of growth and nutritional status on seabird stable isotope ratios. Oecologia 159:42–48CrossRefGoogle Scholar
  46. Takimoto G, Spiller DA, Post DM (2008) Ecosystem size, but not disturbance, determines food chain length on islands of the Bahamas. Ecology 89:3001–3007CrossRefGoogle Scholar
  47. Tewfik A, Rasmussen JB, McCann KS (2005) Anthropogenic enrichment alters a marine benthic food web. Ecology 86:2716–2736CrossRefGoogle Scholar
  48. Thompson A, Bottrell SH (1998) Sulphur isotopic investigation of a polluted raised bog and the uptake of pollutant sulphur by Sphagnum. Environ Pollut 101:201–207PubMedCrossRefGoogle Scholar
  49. Tillberg CV (2004) Friend or foe? A behavioural and stable isotopic investigation of an ant–plant symbiosis. Oecologia 140:506–515PubMedCrossRefGoogle Scholar
  50. Tillberg CV, McCarthy DP, Dolezal AG, Suarez AV (2006) Measuring the trophic ecology of ants using stable isotopes. Insect Soc 53:65–69CrossRefGoogle Scholar
  51. Vanderklift MA, Ponsard S (2003) Sources of variation in consumer-diet δ15N enrichment: a meta-analysis. Oecologia 136:169–182PubMedCrossRefGoogle Scholar
  52. Vander Zanden MJ, Rasmussen JB (1999) Primary consumer δ13C and δ15N and the trophic position of aquatic consumers. Ecology 80:1395–1404CrossRefGoogle Scholar
  53. Votier SC, Bearhop S, Witt MJ, Inger R, Thompson D, Newton J (2010) Individual responses of seabirds to commercial fisheries revealed using GPS tracking, stable isotopes and vessel monitoring systems. J Appl Ecol 47:487–497CrossRefGoogle Scholar
  54. Walters AW, Post DM (2008) An experimental disturbance alters fish size structure but not food chain length in streams. Ecology 89:3261–3267PubMedCrossRefGoogle Scholar
  55. Walsh RPD, Newberry DM (1999) The ecoclimatology of Danum, Sabah, in the context of the world’s rainforest regions, with particular reference to dry periods and their impact. Phil Trans Roy Soc B 354:1869–1883CrossRefGoogle Scholar
  56. Wang L, D’Odorico D, Ries L, Macko SA (2010) Patterns and implications of plant-soil δ13C and δ15N values in African savanna ecosystems. Quaternary Res 73:77–83CrossRefGoogle Scholar
  57. West JB, Bowen GJ, Cerling TE, Ehleringer JR (2006) Stable isotopes as one of nature’s ecological recorders. Trends Ecol and Evol 21:409–414CrossRefGoogle Scholar
  58. Wilson EO, Hölldobler B (2005) The rise of the ants: a phylogenetic and ecological explanation. P Natl Acad Sci USA 102:7411–7414CrossRefGoogle Scholar
  59. Woodcock P, Edwards DP, Fayle TM, Newton RJ, Chey V-K, Bottrell SH, Hamer KC (2011) The conservation value of Southeast Asia’s highly degraded forests: evidence from leaf-litter ants. Phil Trans Roy Soc B 366:3256–3264CrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2012

Authors and Affiliations

  • Paul Woodcock
    • 1
  • David P. Edwards
    • 1
    • 4
  • Rob J. Newton
    • 2
  • Felicity A. Edwards
    • 1
  • Chey Vun Khen
    • 3
  • Simon H. Bottrell
    • 2
  • Keith C. Hamer
    • 1
  1. 1.Institute of Integrative and Comparative BiologyUniversity of LeedsLeedsUK
  2. 2.School of Earth and EnvironmentUniversity of LeedsLeedsUK
  3. 3.Sepilok Forest Research CentreSandakanMalaysia
  4. 4.School of Marine and Tropical BiologyJames Cook UniversityCairnsAustralia

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