Southwestern Africa Rock Hyrax Midden Stable Isotope Data ----------------------------------------------------------------------- World Data Center for Paleoclimatology, Boulder and NOAA Paleoclimatology Program ----------------------------------------------------------------------- NOTE: PLEASE CITE ORIGINAL REFERENCE WHEN USING THIS DATA!!!!! NAME OF DATA SET: Southwestern Africa Rock Hyrax Midden Stable Isotope Data LAST UPDATE: 8/2009 (Original receipt by WDC Paleo) CONTRIBUTOR: Brian Chase, University of Oxford IGBP PAGES/WDCA CONTRIBUTION SERIES NUMBER: 2009-082 WDC PALEO CONTRIBUTION SERIES CITATION: Chase, B.M., et al. 2009. Southwestern Africa Rock Hyrax Midden Stable Isotope Data. IGBP PAGES/World Data Center for Paleoclimatology Data Contribution Series # 2009-082. NOAA/NCDC Paleoclimatology Program, Boulder CO, USA. ORIGINAL REFERENCE: Chase, B.M., M.E. Meadows, L. Scott, D.S.G. Thomas, E. Marais, J. Sealy, and P.J. Reimer. 2009. A record of rapid Holocene climate change preserved in hyrax middens from southwestern Africa. Geology, Vol. 37, No. 8, pp. 703-706, August 2009. doi: 10.1130/G30053A.1. ABSTRACT: The discovery of sensitive paleoenvironmental proxies contained within fossilized rock hyrax middens from the margin of the central Namib Desert, Africa, is providing unprecedented insight into the region's environmental history. High-resolution stable carbon and nitrogen isotope records spanning 0-11,700 cal (calibrated) yr B.P. indicate phases of relatively humid conditions from 8700-7500, 6900-6700, 5600-4900, and 4200-3500 cal yr B.P., with a period of marked aridity occurring from 3500 until ca. 300 cal yr B.P. Transitions between these phases appear to have occurred very rapidly, often within <200 years. Of particular importance are: (1) the observed relationship between regional aridification and the decline in Northern Hemisphere insolation across the Holocene, and (2) the significance of suborbital scale variations in climate that covary strongly with fluctuations in solar forcing. Together, these elements call for a fundamental reexamination of the role of orbital forcing on tropical African systems, and a reconsideration of what factors drive climate change in the region. The quality and resolution of these data far surpass any other evidence available from the region, and the continued development of this unique archive promises to revolutionize paleoenvironmental studies in southern Africa. ADDITIONAL REFERENCES: Ambrose, S.H., and M.J. DeNiro. 1986. The isotopic ecology of East African mammals. Oecologia 69, 395-406. Aranibar, J.N., L. Otter, S.A. Macko, C.J.W. Feral, H.E. Epstein, P.R. Dowty, F. Eckardt, H.H. Shugart, and R.J. Swap. 2004. Nitrogen cycling in the soil-plant system along a precipitation gradient in the Kalahari sands. Global Change Biology 10, 359-373. Codron, D., J. Codron, J. Lee-Thorp, M. Sponheimer, D. de Ruiter, and J. Brink. 2007. Stable isotope characterization of mammalian predator-prey relationships in a South African savanna. European Journal of Wildlife Research, 53, 161-170. Heaton, T.H.E. 1987. The 15N/14N ratios of plants in South Africa and Namibia: relationship to climate and coastal/saline environments. Oecologia 74, 236-246. Heaton, T.H.E., J.C. Vogel, G. von la Chevallerie, and G. Collet. 1986. Climate influence on the isotopic composition of bone nitrogen. Nature 322, 822-823. Hoeck, H.N. 1975. Differential feeding behaviour of the sympatric hyrax: (Procavia johnstoni and Heterohyrax brucei). Oecologia 22, 15-47. Murphy, B.P., and D.M.J.S. Bowman. 2006. Kangaroo metabolism does not cause the relationship between bone collagen d15N and water availability. Functional Ecology 20, 1062-1069. Smith, B.N. and S. Epstein. 1971. Two categories of 13C/12C ratios for higher plants. Plant Physiology 47, 380-384. Swap, R.J., J.N. Aranibar, P.R. Dowty, W.P. Gilhooly, and S.A. Macko. 2004. Natural abundance of 13C and 15N in C3 and C4 vegetation of southern Africa: patterns and implications. Global Change Biology 10, 350-358. Walker, B.H., D. Ludwig, C.S. Holling, and R.M. Peterman. 1981. Stability of semi-arid savanna grazing systems. The Journal of Ecology 69, 473-498. GEOGRAPHIC REGION: Southwestern Africa PERIOD OF RECORD: 11,700 YrBP - present FUNDING SOURCE: Leverhulme Trust DESCRIPTION: Stable isotope data (d13C and d15N) from three Rock Hyrax middens on the south-facing flank of Klein Spitzkoppe, western-central Namibia, Southern Africa (21.8317°S, 15.1955°E). The d13C values vary between -23.4 per mil and -17.0 per mil (Figure 2). As a representation of hyrax diet, these variations primarily reflect the proportion of C3 plants (in this environment, generally trees and shrubs) versus C4 plants (generally grasses) with average d13C value of ~-26 per mil and ~-12per mil respectively (Codron et al., 2007; Smith and Epstein, 1971). Observations indicate that hyraxes consume an exceptionally wide range of plants (as many as 79 species of grass, shrubs, and trees), but prefer grasses to the leaves and bark of trees and shrubs (Hoeck, 1975). In xeric savannah regions such as at Spitzkoppe, however, the latter become an important part of their diet during dry periods when grass is scarce (Hoeck, 1975). Considering this, it is expected that during times of less or less regular rains d13C values would become relatively lower as hyraxes come to depend increasingly on the arboreal taxa that can access reserves of groundwater (Walker et al., 1981). Overall, the d13C records obtained from these middens suggest that marked seasonality has been a part of the region's rainfall regime throughout the Holocene, with C3 plants consistently constituting a significant part of the animals' diet. The d15N values vary from 13.4 to 7.4 per mil. The potential of nitrogen stable isotope compositions as a climatic indicator has long been recognised, but studies of modern ecosystems have produced complex data sets, that have proved difficult to interpret (e.g. Heaton, 1987; Heaton et al., 1986). Among herbivores, 15N abundance in animal tissues is strongly influenced by climate, diet and/or physiology (Ambrose and DeNiro, 1986; Heaton et al., 1986). While early studies focused on the possible effects that animal metabolism would have on the signal (Ambrose and DeNiro, 1986), subsequent studies of d15N values in plants across aridity gradients have indicated that it may not be necessary to look towards herbivore metabolism for the link between d15N values and rainfall, as clear correlations are identified between higher d15N values and decreased rainfall in both C3 and C4 plants (Heaton, 1987; Murphy and Bowman, 2006; Swap et al., 2004) and soils (Aranibar et al., 2004). Murphy and Bowman's (2006) spatially-extensive studies of d15N values in both grass and kangaroo bone from across Australia reveal a remarkably consistent relationship between plant and bone d15N signals, suggesting that water availability, through its influence on the isotopic signature of plants/diet, is the primary control on animal d15N with metabolism having no clear effect. DATA: Column 1: Sample Column 2: d15N/14N, per mil Column 3: d13/12C, per mil Column 4: Age, Calendar years before present Sample d15N/14N d13/12C CalYrBP SPZ 2-1 9.02 -20.23 -27 SPZ 2-3 9.69 -20.51 17 SPZ 2-4 9.13 -21.22 44 SPZ 2-5 9.47 -20.53 66 SPZ 2-6 10.84 -20.50 92 SPZ 2-7 11.15 -17.82 119 SPZ 2-8 11.27 -18.83 146 SPZ 2-9 10.45 -19.22 168 SPZ 2-11 10.68 -18.32 212 SPZ 2-13 9.95 -19.61 258 SPZ 2-14 11.59 -19.53 321 SPZ 2-16 12.33 -19.78 372 SPZ 2-17 12.41 -18.77 399 SPZ 2-18 12.20 -20.32 435 SPZ 2-19 11.97 -20.25 472 SPZ 2-20 11.73 -20.21 507 SPZ 2-21 11.81 -20.19 538 SPZ 2-22 11.42 -20.19 566 SPZ 2-23 11.36 -20.22 597 SPZ 2-24 11.97 -21.66 622 SPZ 2-25 11.82 -21.95 638 SPZ 2-26 11.94 -23.38 675 SPZ 2-27 11.16 -22.92 712 SPZ 2-28 12.04 -19.94 753 SPZ 2-29 12.69 -20.83 762 SPZ 2-30 11.89 -20.42 815 SPZ 2-31 11.06 -19.15 856 SPZ 2-32 10.89 -19.53 889 SPZ 2-33 11.53 -20.95 923 SPZ 2-34 12.01 -19.70 951 SPZ 2-35 10.60 -19.92 988 SPZ 2-36 11.73 -19.39 1024 SPZ 2-37 12.49 -19.60 1066 SPZ 2-38 12.28 -18.91 1093 SPZ 2-39 12.37 -18.62 1126 SPZ 2-40 12.08 -20.04 1162 SPZ 2-41 12.44 -19.47 1193 SPZ 2-42 12.11 -20.12 1226 SPZ 2-43 12.15 -20.41 1252 SPZ 2-44 13.03 -19.30 1293 SPZ 2-45 12.28 -20.05 1347 SPZ 2-46 10.96 -19.40 1408 SPZ 2-47 12.38 -19.61 1464 SPZ 2-48 11.73 -20.42 1512 SPZ 2-49 11.81 -20.41 1566 SPZ 2-50 12.42 -22.25 1620 SPZ 2-51 11.94 -20.29 1676 SPZ 2-52 11.40 -20.64 1726 SPZ 2-53 10.91 -21.20 1771 SPZ 2-54 11.97 -21.72 1805 SPZ 2-55 12.19 -21.17 1843 SPZ 2-56 11.46 -21.58 1875 SPZ 2-57 12.01 -22.72 1922 SPZ 2-58 12.24 -20.27 1959 SPZ 2-59 11.95 -19.67 1997 SPZ 2-62 11.84 -21.29 2117 SPZ 2-63 11.44 -21.65 2144 SPZ 2-64 11.75 -21.10 2205 SPZ 2-65 11.75 -21.30 2252 SPZ 2-66 11.34 -21.01 2250 SPZ 2-67 11.43 -20.52 2290 SPZ 2-68 11.71 -21.05 2340 SPZ 2-69 11.60 -21.01 2381 SPZ 2-70 11.25 -20.87 2431 SPZ 2-71 11.38 -20.70 2493 SPZ 2-72 11.10 -20.92 2533 SPZ 2-73 12.29 -22.01 2586 SPZ 2-74 10.84 -20.64 2657 SPZ 2-75 11.69 -19.79 2698 SPZ 2-76 13.37 -20.11 2762 SPZ 2-77 12.72 -20.57 2808 SPZ 2-78 11.60 -18.83 2832 SPZ 5-7 11.76 -20.12 2845 SPZ 5-8 11.13 -20.81 2922 SPZ 5-9 11.72 -20.43 2982 SPZ 5-10 11.32 -20.64 3094 SPZ 5-11 12.25 -21.81 3145 SPZ 5-12 11.86 -21.48 3208 SPZ 5-13 12.09 -21.69 3283 SPZ 5-14 11.90 -20.56 3345 SPZ 5-15 10.40 -21.05 3409 SPZ 5-16 10.03 -19.26 3459 SPZ 5-17 9.90 -20.19 3497 SPZ 5-18 9.08 -20.62 3535 SPZ 5-19 10.55 -20.65 3581 SPZ 5-20 11.38 -20.72 3622 SPZ 5-21 11.09 -21.14 3652 SPZ 5-22 10.97 -19.90 3689 SPZ 5-23 11.62 -20.47 3727 SPZ 5-24 11.79 -20.31 3763 SPZ 5-25 11.56 -20.43 3798 SPZ 5-26 9.58 -19.76 3825 SPZ 5-27 11.03 -19.75 3863 SPZ 5-28 8.87 -19.22 3898 SPZ 5-29 9.78 -18.81 3935 SPZ 5-30 10.68 -19.23 4005 SPZ 5-31 8.51 -17.17 4067 SPZ 5-32 9.27 -17.04 4129 SPZ 5-33 10.12 -17.62 4223 SPZ 5-34 11.04 -20.60 4296 SPZ 5-35 11.00 -20.08 4374 SPZ 5-36 11.29 -19.39 4457 SPZ 5-37 10.50 -17.92 4511 SPZ 5-38 10.06 -18.37 4584 SPZ 5-39 11.11 -18.49 4640 SPZ 5-40 10.36 -17.64 4724 SPZ 5-41 10.99 -19.70 4769 SPZ 5-42 12.13 -19.03 4818 SPZ 5-43 9.54 -17.59 4915 SPZ 5-44 10.31 -18.77 5004 SPZ 5-45 10.57 -18.83 5103 SPZ 5-46 9.73 -18.59 5195 SPZ 5-47 10.19 -19.22 5286 SPZ 5-48 8.93 -18.68 5335 SPZ 5-49 9.14 -19.09 5428 SPZ 5-50 8.90 -18.50 5488 SPZ 5-51 9.43 -19.00 5550 SPZ 5-52 10.07 -18.46 5609 SPZ 5-53 10.19 -19.30 5661 SPZ 5-54 9.97 -19.56 5742 SPZ 5-55 10.44 -18.91 5804 SPZ 5-56 9.99 -18.70 5877 SPZ 5-57 10.59 -19.20 5931 SPZ-5-58 10.29 -19.31 5991 SPZ-5-59 10.94 -20.25 6071 SPZ-5-60 10.07 -19.51 6136 SPZ-5-61 10.84 -19.52 6190 SPZ 5-62 10.31 -18.82 6255 SPZ 3-41 10.82 -19.39 6301 SPZ 3-40 10.26 -19.69 6431 SPZ 3-39 10.11 -19.65 6552 SPZ 3-38 9.68 -19.19 6697 SPZ 3-37 9.59 -19.81 6849 SPZ 3-36 10.32 -19.82 6986 SPZ 3-35 10.02 -18.77 7191 SPZ 3-34 10.43 -18.96 7316 SPZ 3-33 10.20 -18.75 7410 SPZ 3-32 10.12 -18.94 7480 SPZ 3-31 9.02 -18.54 7559 SPZ 3-30 8.95 -19.10 7616 SPZ 3-29 7.44 -18.94 7706 SPZ 3-28 9.08 -19.13 7742 SPZ 3-27 8.55 -19.48 7779 SPZ 3-26 8.94 -19.67 7808 SPZ 3-25 8.55 -19.79 7844 SPZ 3-24 10.13 -19.46 7867 SPZ 3-23 9.25 -19.09 7896 SPZ 3-22 8.12 -18.29 7983 SPZ 3-21 7.87 -18.38 8114 SPZ 3-20 7.51 -18.99 8220 SPZ 3-19 8.03 -19.20 8514 SPZ 3-18 8.49 -19.54 8637 SPZ 3-17 9.56 -19.65 8743 SPZ 3-16 9.57 -19.65 8907 SPZ 3-15 8.43 -18.96 9103 SPZ 3-14 9.45 -19.56 9250 SPZ 3-13 9.50 -19.25 9422 SPZ 3-12 9.33 -19.11 9569 SPZ 3-11 9.92 -19.31 9782 SPZ 3-10 8.79 -19.01 9987 SPZ 3-9 8.95 -19.28 10175 SPZ 3-8 8.65 -19.10 10422 SPZ 3-6 8.80 -19.56 10718 SPZ 3-5 9.35 -19.80 11006 SPZ 3-4 9.51 -19.35 11194 SPZ 3-3 9.69 -19.68 11329 SPZ 3-2 9.96 -19.54 11509 SPZ 3-1 10.13 -18.80 11724