Altitudinal gradients of grassland carbon and nitrogen isotope composition are recorded in the hair of grazers

Aim The hair of grazers provides an isotopic record of environmental and nutritional signals. Here, we assess the effect of altitude on the carbon and nitrogen isotope composition of the hair of ruminant grazers and its relation to grassland vegetation, to evaluate the use of hair isotope data for ecosystem reconstruction, animal nutritional ecology and biogeochemical studies in montane environments. Location European Alps. Methods We sampled grassland vegetation (pure C 3 ) and the hair of ruminants along an altitudinal gradient (400-2500 m), and analysed their isotope composition (δ 13 C and δ 15 N). Results were compared with published effects of altitude on 13 C in C 3 plants at the species level and on 15 N at the community level. The study was complemented with a comparison of diet and hair isotope composition in ruminants held in confinement. Results δ 13 C of hair increased (c. 1.1‰ km -1 ) and δ 15 N decreased (c. 1.1‰ km -1 ) with altitude. The same changes occurred in local grassland vegetation, and in regional to global grassland data sets. Offsets between hair and vegetation 13 C or 15 N ('diet-hair shift') were independent of altitude. Sheep (Ovis aries) and cattle (Bos taurus) exhibited a 13 C shift near +3‰, but that of goats (Capra hircus) was larger (+4.2‰) in alpine environments and in confinement. The diet-hair shift for 15 N was more variable (+2.1 to +3.6‰). Main conclusions Grazer hair provides a faithful spatially and temporally integrated record of grassland isotope composition, useful for ecosystem and environment reconstruction. The effect of altitude on hair 15 N is important for studies of trophic relationships: an altitude shift of 2000 m produced the same effect in hair 15 N as would a shift from an animal tissue-based to a plant-based diet. The similarity of altitude effects on δ 13 C of individual plant species, vegetation and hair indicates that the effect of altitude on species-level 'intrinsic water use efficiency' scales up linearly to the community and landscape level.

[1]  D. Bowman,et al.  Kangaroo metabolism does not cause the relationship between bone collagen δ15N and water availability , 2006 .

[2]  S. Davanzo,et al.  Spatial and temporal variations in the 13C / 12C and 15N / 14N ratios of mammoth hairs: Palaeodiet and palaeoclimatic implications , 2006 .

[3]  K. Auerswald,et al.  Hair of grazing cattle provides an integrated measure of the effects of site conditions and interannual weather variability on δ13C of temperate humid grassland , 2006 .

[4]  Gabriel J Bowen,et al.  Stable isotopes as one of nature's ecological recorders. , 2006, Trends in ecology & evolution.

[5]  Marek Drewnik.  The effect of environmental conditions on the decomposition rate of cellulose in mountain soils , 2006 .

[6]  G. Wittemyer,et al.  Stable isotopes in elephant hair document migration patterns and diet changes. , 2006, Proceedings of the National Academy of Sciences of the United States of America.

[7]  C. Lécuyer,et al.  Box-modeling of 15N/14N in mammals , 2006, Oecologia.

[8]  K. Hobson,et al.  NUTRITION, PHYSIOLOGY, AND STABLE ISOTOPES: NEW INFORMATION FROM FASTING AND MOLTING PENGUINS , 2005 .

[9]  K. Auerswald,et al.  Carbon and nitrogen stable isotope composition of cattle hair: ecological fingerprints of production systems? , 2005 .

[10]  Yude Pan,et al.  Leaf area index and net primary productivity along subtropical to alpine gradients in the Tibetan Plateau , 2004 .

[11]  A. Lüscher,et al.  The relative contribution of symbiotic N2 fixation and other nitrogen sources to grassland ecosystems along an altitudinal gradient in the Alps , 2000, Plant and Soil.

[12]  M. F. W. D. Vries,et al.  Foraging strategy of cattle in patchy grassland , 1994, Oecologia.

[13]  C. Körner,et al.  Carbon isotope discrimination by plants follows latitudinal and altitudinal trends , 1991, Oecologia.

[14]  L. Tieszen,et al.  Fractionation and turnover of stable carbon isotopes in animal tissues: Implications for δ13C analysis of diet , 1983, Oecologia.

[15]  C. Körner,et al.  A global survey of carbon isotope discrimination in plants from high altitude , 2004, Oecologia.

[16]  J. Ehleringer,et al.  Turnover of carbon isotopes in tail hair and breath CO2 of horses fed an isotopically varied diet , 2004, Oecologia.

[17]  K. Auerswald,et al.  Reconstruction of the isotopic history of animal diets by hair segmental analysis. , 2003, Rapid communications in mass spectrometry : RCM.

[18]  N. Wrage,et al.  Emission of gaseous nitrogen oxides from an extensively managed grassland in NE Bavaria, Germany , 2003 .

[19]  J. Ehleringer,et al.  An experimental study of carbon-isotope fractionation between diet, hair, and feces of mammalian herbivores , 2003 .

[20]  A. Austin,et al.  Global patterns of the isotopic composition of soil and plant nitrogen , 2003 .

[21]  J. Craine,et al.  Covariation in leaf and root traits for native and non-native grasses along an altitudinal gradient in New Zealand , 2003, Oecologia.

[22]  N. Wrage,et al.  Emission of gaseous nitrogen oxides from an extensively managed grassland in NE Bavaria, Germany. , 2003 .

[23]  J. Ehleringer,et al.  Nitrogen isotopes in mammalian herbivores: hair δ15N values from a controlled feeding study , 2003 .

[24]  L. Handley,et al.  Interspecific variation in potential water-use efficiency and its relation to plant species abundance in a water-limited grassland , 2001 .

[25]  P. Matson,et al.  Net primary productivity and nutrient cycling across a mesic to wet precipitation gradient in Hawaiian montane forest , 2001, Oecologia.

[26]  K. Hobson,et al.  Using stable carbon (δ13C) and nitrogen (δ15N) isotopes to infer trophic relationships among black and grizzly bears in the upper Columbia River basin, British Columbia , 2000 .

[27]  A. Lüscher,et al.  Symbiotic N2 fixation of various legume species along an altitudinal gradient in the Swiss Alps , 2000 .

[28]  J. Marshall,et al.  Altitude trends in conifer leaf morphology and stable carbon isotope composition , 2000, Oecologia.

[29]  K. Hobson.  Tracing origins and migration of wildlife using stable isotopes: a review , 1999, Oecologia.

[30]  T. Cerling,et al.  Carbon isotope fractionation between diet and bioapatite in ungulate mammals and implications for ecological and paleoecological studies , 1999, Oecologia.

[31]  B. MacFadden,et al.  Ancient latitudinal gradients of C3/C4 grasses interpreted from stable isotopes of New World Pleistocene horse (Equus) teeth , 1999 .

[32]  A. Austin,et al.  The 15N natural abundance (d15N) of ecosystem samples reflects measures of water availability , 1999 .

[33]  P. Vitousek,et al.  Nutrient dynamics on a precipitation gradient in Hawai'i , 1998, Oecologia.

[34]  P. Högberg,et al.  Tansley Review No. 95 15 N natural abundance in soil-plant systems. , 1997, The New phytologist.

[35]  Peter M. Vitousek,et al.  PRIMARY PRODUCTIVITY AND ECOSYSTEM DEVELOPMENT ALONG AN ELEVATIONAL GRADIENT ON MAUNA LOA, HAWAI‘I , 1997 .

[36]  F. Woodward,et al.  Experimental Investigations on the Environmental Determination of δ13C at Different Altitudes , 1990 .

[37]  F. Woodward,et al.  Field Measurements of Photosynthesis, Stomatal Conductance, Leaf Nitrogen and δ 13 C Along Altitudinal Gradients in Scotland , 1989 .

[38]  J. Ehleringer,et al.  Carbon Isotope Discrimination and Photosynthesis , 1989 .

[39]  T. Yoneyama,et al.  Variations of natural 15N abundances in the tissues and digesta of domestic animals. , 1987, Radioisotopes.

[40]  D. Schoeller,et al.  Geographical variations in the carbon isotope composition of the diet and hair in contemporary man. , 1982, Biomedical mass spectrometry.

[41]  A. Mariotti,et al.  The abundance of natural nitrogen 15 in the organic matter of soils along an altitudinal gradient (chablais, haute savoie, France) , 1980 .

[42]  M. J. Deniro,et al.  Influence of Diet On the Distribtion of Nitrogen Isotopes in Animals , 1978 .

[43]  D. J. Minson,et al.  Differences in natural carbon isotope ratios of milk and hair from cattle grazing tropical and temperate pastures , 1975, Nature.