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Theoretical Ecology

, Volume 11, Issue 2, pp 161–173 | Cite as

Zooming in on coarse plant functional types—simulated response of savanna vegetation composition in response to aridity and grazing

  • Dirk Lohmann
  • Tong Guo
  • Britta Tietjen
ORIGINAL PAPER

Abstract

Precipitation and land use in terms of livestock grazing have been identified as two of the most important drivers structuring the vegetation composition of semi-arid and arid savannas. Savanna research on the impact of these drivers has widely applied the so-called plant functional type (PFT) approach, grouping the vegetation into two or three broad types (here called meta-PFTs): woody plants and grasses, which are sometimes divided into perennial and annual grasses. However, little is known about the response of functional traits within these coarse types towards water availability or livestock grazing. In this study, we extended an existing eco-hydrological savanna vegetation model to capture trait diversity within the three broad meta-PFTs to assess the effects of both grazing and mean annual precipitation (MAP) on trait composition along a gradient of both drivers. Our results show a complex pattern of trait responses to grazing and aridity. The response differs for the three meta-PFTs. From our findings, we derive that trait responses to grazing and aridity for perennial grasses are similar, as suggested by the convergence model for grazing and aridity. However, we also see that this only holds for simulations below a MAP of 500 mm. This combined with the finding that trait response differs between the three meta-PFTs leads to the conclusion that there is no single, universal trait or set of traits determining the response to grazing and aridity. We finally discuss how simulation models including trait variability within meta-PFTs are necessary to understand ecosystem responses to environmental drivers, both locally and globally and how this perspective will help to extend conceptual frameworks of other ecosystems to savanna research.

Keywords

Traits Dryland Degradation Shrub encroachment Simulation Eco-hydrological model EcoHyD 

Notes

Acknowledgements

This study was supported by the China Scholarship Council (CSC, TG) and by the BMBF in the framework of the OPTIMASS project (01LL1302A, DL and 01LL1302B BT). The authors thank the High-Performance Computing system at Freie Universität Berlin (http://www.zedat.fu-berlin.de/HPC). We further want to thank two anonymous reviewers for their constructive comments on our study.

Supplementary material

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References

  1. Accatino F, De Michele C, Vezzoli R, Donzelli D, Scholes RJ (2010) Tree–grass co-existence in savanna: interactions of rain and fire. J Theor Biol 267(2):235–242.  https://doi.org/10.1016/j.jtbi.2010.08.012 CrossRefPubMedGoogle Scholar
  2. Adler PB, Milchunas DG, Lauenroth WK, Sala OE, Burke IC (2004) Functional traits of graminoids in semi-arid steppes: a test of grazing histories. J Appl Ecol 41(4):653–663.  https://doi.org/10.1111/j.0021-8901.2004.00934.x CrossRefGoogle Scholar
  3. Adler PB, Milchunas DG, Sala OE, Burke IC, Lauenroth WK (2005) Plant traits and ecosystem grazing effects: comparison of U.S. sagebrush steppe and patagonian steppe. Ecol Appl 15(2):774–792.  https://doi.org/10.1890/04-0231 CrossRefGoogle Scholar
  4. Archibald S, Scholes RJ (2007) Leaf green-up in a semi-arid African savanna –separating tree and grass responses to environmental cues. J Veg Sci 18(4):583–594.  https://doi.org/10.1111/j.1654-1103.2007.tb02572.x CrossRefGoogle Scholar
  5. Bestelmeyer BT, Ward JP, Havstad KM (2006) Soil-geomorphic heterogeneity governs patchy vegetation dynamics at an arid ecotone. Ecology 87(4):963–973.  https://doi.org/10.1890/0012-9658(2006)87[963:Shgpvd]2.0.Co;2 CrossRefPubMedGoogle Scholar
  6. Boer M, Stafford Smith DM (2003) A plant functional approach to the prediction of changes in Australian rangeland vegetation under grazing and fire. J Veg Sci 14(3):333–344.  https://doi.org/10.1111/j.1654-1103.2003.tb02159.x CrossRefGoogle Scholar
  7. Bond WJ, Midgley GF (2012) Carbon dioxide and the uneasy interactions of trees and savannah grasses. Philos Trans R Soc B Biol Sci 367(1588):601–612.  https://doi.org/10.1098/rstb.2011.0182 CrossRefGoogle Scholar
  8. Buitenwerf R, Swemmer AM, Peel MJS (2011) Long-term dynamics of herbaceous vegetation structure and composition in two African savanna reserves. J Appl Ecol 48(1):238–246.  https://doi.org/10.1111/j.1365-2664.2010.01895.x CrossRefGoogle Scholar
  9. D’Odorico P, Bhattachan A, Davis KF, Ravi S, Runyan CW (2013) Global desertification: drivers and feedbacks. Adv Water Resour 51:326–344.  https://doi.org/10.1016/j.advwatres.2012.01.013 CrossRefGoogle Scholar
  10. De Bello F, LepŠ JAN, SebastiÀ M-T (2005) Predictive value of plant traits to grazing along a climatic gradient in the Mediterranean. J Appl Ecol 42(5):824–833.  https://doi.org/10.1111/j.1365-2664.2005.01079.x CrossRefGoogle Scholar
  11. Díaz S, Noy-Meir I, Cabido M (2001) Can grazing response of herbaceous plants be predicted from simple vegetative traits? J Appl Ecol 38(3):497–508.  https://doi.org/10.1046/j.1365-2664.2001.00635.x CrossRefGoogle Scholar
  12. Diaz S, Lavorel S, De Bello F, Quetier F, Grigulis K, Robson TM (2007) Incorporating plant functional diversity effects in ecosystem service assessments. Proc Natl Acad Sci U S A 104(52):20684–20689.  https://doi.org/10.1073/pnas.0704716104 CrossRefPubMedPubMedCentralGoogle Scholar
  13. Díaz S et al (2007) Plant trait responses to grazing—a global synthesis. Glob Chang Biol 13(2):313–341.  https://doi.org/10.1111/j.1365-2486.2006.01288.x CrossRefGoogle Scholar
  14. D'Onofrio D, Baudena M, D'Andrea F, Rietkerk M, Provenzale A (2015) Tree-grass competition for soil water in arid and semiarid savannas: the role of rainfall intermittency. Water Resour Res 51(1):169–181.  https://doi.org/10.1002/2014wr015515 CrossRefGoogle Scholar
  15. Eldridge DJ, Bowker MA, Maestre FT, Roger E, Reynolds JF, Whitford WG (2011) Impacts of shrub encroachment on ecosystem structure and functioning: towards a global synthesis. Ecol Lett 14(7):709–722.  https://doi.org/10.1111/j.1461-0248.2011.01630.x CrossRefPubMedPubMedCentralGoogle Scholar
  16. Eldridge DJ, Maestre FT, Maltez-Mouro S, Bowker MA (2012) A global database of shrub encroachment effects on ecosystem structure and functioning. Ecology 93(11):2499–2499.  https://doi.org/10.1890/12-0749.1 CrossRefGoogle Scholar
  17. Eldridge DJ, Beecham G, Grace JB (2015) Do shrubs reduce the adverse effects of grazing on soil properties? Ecohydrology 8(8):1503–1513.  https://doi.org/10.1002/eco.1600 CrossRefGoogle Scholar
  18. Eldridge DJ, Delgado-Baquerizo M, Travers SK, Val J, Oliver I (2016) Do grazing intensity and herbivore type affect soil health? Insights from a semi-arid productivity gradient. J Appl Ecol 54(3):1–10.  https://doi.org/10.1111/1365-2664.12834 CrossRefGoogle Scholar
  19. Evans SE, Byrne KM, Lauenroth WK, Burke IC (2011) Defining the limit to resistance in a drought-tolerant grassland: long-term severe drought significantly reduces the dominant species and increases ruderals. J Ecol 99(6):1500–1507.  https://doi.org/10.1111/j.1365-2745.2011.01864.x CrossRefGoogle Scholar
  20. Fensham RJ, Fairfax RJ, Archer SR (2005) Rainfall, land use and woody vegetation cover change in semi-arid Australian savanna. J Ecol 93(3):596–606.  https://doi.org/10.1111/j.1365-2745.2005.00998.x CrossRefGoogle Scholar
  21. Graz FP (2008) The woody weed encroachment puzzle: gathering pieces. Ecohydrology 1(4):340–348.  https://doi.org/10.1002/eco.28 CrossRefGoogle Scholar
  22. Grime JP (2001) Plant strategies, vegetation processes, and ecosystem properties, 2nd edn. Wiley, University of Sheffield, UKGoogle Scholar
  23. Guo T, Lohmann D, Ratzmann G, Tietjen B (2016) Response of semi-arid savanna vegetation composition towards grazing along a precipitation gradient—the effect of including plant heterogeneity into an ecohydrological savanna model. Ecol Model 325:47–56.  https://doi.org/10.1016/j.ecolmodel.2016.01.004 CrossRefGoogle Scholar
  24. Hanke W, Bohner J, Dreber N, Jurgens N, Schmiedel U, Wesuls D, Dengler J (2014) The impact of livestock grazing on plant diversity: an analysis across dryland ecosystems and scales in southern Africa. Ecol Appl 24(5):1188–1203.  https://doi.org/10.1890/13-0377.1 CrossRefPubMedGoogle Scholar
  25. Higgins SI, Kantelhardt J, Scheiter S, Boerner J (2007) Sustainable management of extensively managed savanna rangelands. Ecol Econ 62(1):102–114.  https://doi.org/10.1016/j.ecolecon.2006.05.019 CrossRefGoogle Scholar
  26. Higgins SI, Scheiter S, Sankaran M (2010) The stability of African savannas: insights from the indirect estimation of the parameters of a dynamic model. Ecology 91(6):1682–1692.  https://doi.org/10.1890/08-1368.1 CrossRefPubMedGoogle Scholar
  27. Jackson RB, Banner JL, Jobbagy EG, Pockman WT, Wall DH (2002) Ecosystem carbon loss with woody plant invasion of grasslands. Nature 418(6898):623–626.  https://doi.org/10.1038/nature00910 CrossRefPubMedGoogle Scholar
  28. Jeltsch F, Milton SJ, Dean WRJ, Van Rooyen N (1997) Analysing shrub encroachment in the southern Kalahari: a grid-based modelling approach. J Appl Ecol 34(6):1497–1508.  https://doi.org/10.2307/2405265 CrossRefGoogle Scholar
  29. Jeltsch F, Weber GE, Grimm V (2000) Ecological buffering mechanisms in savannas: a unifying theory of long-term tree-grass coexistence. Plant Ecol 150(1/2):161–171.  https://doi.org/10.1023/A:1026590806682 CrossRefGoogle Scholar
  30. Jeltsch F, Moloney KA, Schurr FM, Kochy M, Schwager M (2008) The state of plant population modelling in light of environmental change. Perspect Plant Ecol Evol Syst 9(3-4):171–189.  https://doi.org/10.1016/j.ppees.2007.11.004 CrossRefGoogle Scholar
  31. Joubert DF, Rothauge A, Smit GN (2008) A conceptual model of vegetation dynamics in the semiarid Highland savanna of Namibia, with particular reference to bush thickening by Acacia mellifera. J Arid Environ 72(12):2201–2210.  https://doi.org/10.1016/j.jaridenv.2008.07.004 CrossRefGoogle Scholar
  32. Kattge J et al (2011) TRY—a global database of plant traits. Glob Chang Biol 17(9):2905–2935.  https://doi.org/10.1111/j.1365-2486.2011.02451.x CrossRefPubMedCentralGoogle Scholar
  33. Klumpp K, Fontaine S, Attard E, Le Roux X, Gleixner G, Soussana J-F (2009) Grazing triggers soil carbon loss by altering plant roots and their control on soil microbial community. J Ecol 97(5):876–885.  https://doi.org/10.1111/j.1365-2745.2009.01549.x CrossRefGoogle Scholar
  34. Lauenroth WK, Sala OE (1992) Long-term forage production of North American shortgrass steppe. Ecol Appl 2(4):397–403.  https://doi.org/10.2307/1941874 CrossRefPubMedGoogle Scholar
  35. Liedloff AC, Cook GD (2007) Modelling the effects of rainfall variability and fire on tree populations in an Australian tropical savanna with the Flames simulation model. Ecol Model 201(3-4):269–282.  https://doi.org/10.1016/j.ecolmodel.2006.09.013 CrossRefGoogle Scholar
  36. Linstädter A, Schellberg J, Brüser K, Moreno García CA, Oomen RJ, du Preez CC, Ruppert JC, Ewert F (2014) Are there consistent gazing indicators in drylands? Testing plant functional types of various complexity in South Africa’s grassland and savanna biomes. PLoS One 9(8):e104672.  https://doi.org/10.1371/journal.pone.0104672 CrossRefPubMedPubMedCentralGoogle Scholar
  37. Lohmann D, Tietjen B, Blaum N, Joubert DF, Jeltsch F (2012) Shifting thresholds and changing degradation patterns: climate change effects on the simulated long-term response of a semi-arid savanna to grazing. J Appl Ecol 49(4):814–823.  https://doi.org/10.1111/j.1365-2664.2012.02157.x CrossRefGoogle Scholar
  38. Lohmann D, Tietjen B, Blaum N, Joubert DF, Jeltsch F (2014) Prescribed fire as a tool for managing shrub encroachment in semi-arid savanna rangelands. J Arid Environ 107:49–56.  https://doi.org/10.1016/j.jaridenv.2014.04.003 CrossRefGoogle Scholar
  39. Ludwig JA, Coughenour MB, Liedloff AC, Dyer R (2001) Modelling the resilience of Australian savanna systems to grazing impacts. Environ Int 27(2-3):167–172.  https://doi.org/10.1016/S0160-4120(01)00078-2 CrossRefPubMedGoogle Scholar
  40. Maestre FT, Quero JL, Gotelli NJ, Escudero A, Ochoa V, Delgado-Baquerizo M, Garcia-Gomez M, Bowker MA, Soliveres S, Escolar C, Garcia-Palacios P, Berdugo M, Valencia E, Gozalo B, Gallardo A, Aguilera L, Arredondo T, Blones J, Boeken B, Bran D, Conceicao AA, Cabrera O, Chaieb M, Derak M, Eldridge DJ, Espinosa CI, Florentino A, Gaitan J, Gatica MG, Ghiloufi W, Gomez-Gonzalez S, Gutierrez JR, Hernandez RM, Huang X, Huber-Sannwald E, Jankju M, Miriti M, Monerris J, Mau RL, Morici E, Naseri K, Ospina A, Polo V, Prina A, Pucheta E, Ramirez-Collantes DA, Romao R, Tighe M, Torres-Diaz C, Val J, Veiga JP, Wang D, Zaady E (2012) Plant species richness and ecosystem multifunctionality in global drylands. Science 335(6065):214–218.  https://doi.org/10.1126/science.1215442 CrossRefPubMedPubMedCentralGoogle Scholar
  41. May F, Giladi I, Ristow M, Ziv Y, Jeltsch F (2013) Plant functional traits and community assembly along interacting gradients of productivity and fragmentation. Perspect Plant Ecol Evol Syst 15(6):304–318.  https://doi.org/10.1016/j.ppees.2013.08.002 CrossRefGoogle Scholar
  42. Mayfield MM, Bonser SP, Morgan JW, Aubin I, McNamara S, Vesk PA (2010) What does species richness tell us about functional trait diversity? Predictions and evidence for responses of species and functional trait diversity to land-use change. Glob Ecol Biogeogr 19:423–431.  https://doi.org/10.1111/j.1466-8238.2010.00532.x CrossRefGoogle Scholar
  43. McIntyre S, Lavorel S (2001) Livestock grazing in subtropical pastures: steps in the analysis of attribute response and plant functional types. J Ecol 89(2):209–226.  https://doi.org/10.1046/j.1365-2745.2001.00535.x CrossRefGoogle Scholar
  44. McIntyre S, Lavorel S, Landsberg J, Forbes TDA (1999) Disturbance response in vegetation – towards a global perspective on functional traits. J Veg Sci 10(5):621–630.  https://doi.org/10.2307/3237077 CrossRefGoogle Scholar
  45. Metzger JC, Landschreiber L, Gröngröft A, Eschenbach A (2014) Soil evaporation under different types of land use in southern African savanna ecosystems. J Plant Nutr Soil Sci 177(3):468–475.  https://doi.org/10.1002/jpln.201300257 CrossRefGoogle Scholar
  46. Midgley JJ, Lawes MJ, Chamaillé-Jammes S (2010) Savanna woody plant dynamics: the role of fire and herbivory, separately and synergistically. Aust J Bot 58(1):1–11.  https://doi.org/10.1071/BT09034 CrossRefGoogle Scholar
  47. Milchunas DG, Lauenroth WK (1993) Quantitative effects of grazing on vegetation and soils over a global range of environments. Ecol Monogr 63(4):327–366.  https://doi.org/10.2307/2937150 CrossRefGoogle Scholar
  48. Milchunas DG, Sala OE, Lauenroth WK (1988) A generalized model of the effects of grazing by large herbivores on grassland community structure. Am Nat 132(1):87–106.  https://doi.org/10.1086/284839 CrossRefGoogle Scholar
  49. Moncrieff GR, Scheiter S, Slingsby JA, Higgins SI (2015) Understanding global change impacts on South African biomes using dynamic vegetation models. S Afr J Bot 101:16–23.  https://doi.org/10.1016/j.sajb.2015.02.004 CrossRefGoogle Scholar
  50. Orr DM, O’Reagain PJ (2011) Managing for rainfall variability: impacts of grazing strategies on perennial grass dynamics in a dry tropical savanna. Rangel J 33(2):209–220.  https://doi.org/10.1071/Rj11032 CrossRefGoogle Scholar
  51. Pachzelt A, Rammig A, Higgins S, Hickler T (2013) Coupling a physiological grazer population model with a generalized model for vegetation dynamics. Ecol Model 263:92–102.  https://doi.org/10.1016/j.ecolmodel.2013.04.025 CrossRefGoogle Scholar
  52. Porensky LM, Wittman SE, Riginos C, Young TP (2013) Herbivory and drought interact to enhance spatial patterning and diversity in a savanna understory. Oecologia 173(2):591–602.  https://doi.org/10.1007/s00442-013-2637-4 CrossRefPubMedGoogle Scholar
  53. Quaas MF, Baumgärtner S, Becker C, Frank K, Müller B (2007) Uncertainty and sustainability in the management of rangelands. Ecol Econ 62(2):251–266.  https://doi.org/10.1016/j.ecolecon.2006.03.028 CrossRefGoogle Scholar
  54. Quiroga RE, Golluscio RA, Blanco LJ, Fernández RJ (2010) Aridity and grazing as convergent selective forces: an experiment with an arid Chaco bunchgrass. Ecol Appl 20(7):1876–1889.  https://doi.org/10.1890/09-0641.1 CrossRefPubMedGoogle Scholar
  55. Ratzmann G, Gangkofner U, Tietjen B, Fensholt R (2016) Dryland vegetation functional response to altered rainfall amounts and variability derived from satellite time series data. Remote Sens Basel 8(12):1026.  https://doi.org/10.3390/rs8121026 CrossRefGoogle Scholar
  56. Reynolds JF, Maestre FT, Kemp PR, Stafford-Smith DM, Lambin E (2007) Natural and human dimensions of land degradation in drylands: causes and consequences. In: Canadell JG, Pataki DE, Pitelka LF (eds) Terrestrial ecosystems in a changing world. Springer Berlin Heidelberg, Berlin, Heidelberg, pp 247–257.  https://doi.org/10.1007/978-3-540-32730-1_20 CrossRefGoogle Scholar
  57. Riginos C (2009) Grass competition suppresses savanna tree growth across multiple demographic stages. Ecology 90(2):335–340.  https://doi.org/10.1890/08-0462.1 CrossRefPubMedGoogle Scholar
  58. Roques KG, O’Connor TG, Watkinson AR (2001) Dynamics of shrub encroachment in an African savanna: relative influences of fire, herbivory, rainfall and density dependence. J Appl Ecol 38(2):268–280.  https://doi.org/10.1046/j.1365-2664.2001.00567.x CrossRefGoogle Scholar
  59. Rutherford MC, Powrie LW (2013) Impacts of heavy grazing on plant species richness: a comparison across rangeland biomes of South Africa. S Afr J Bot 87:146–156.  https://doi.org/10.1016/j.sajb.2013.03.020 CrossRefGoogle Scholar
  60. Sakschewski B, von Bloh W, Boit A, Rammig A, Kattge J, Poorter L, Peñuelas J, Thonicke K (2015) Leaf and stem economics spectra drive diversity of functional plant traits in a dynamic global vegetation model. Glob Chang Biol 21(7):2711–2725.  https://doi.org/10.1111/gcb.12870 CrossRefPubMedGoogle Scholar
  61. Sakschewski B, von Bloh W, Boit A, Poorter L, Peña-Claros M, Heinke J, Joshi J, Thonicke K (2016) Resilience of Amazon forests emerges from plant trait diversity. Nat Clim Chang 6(11):1032–1036.  https://doi.org/10.1038/nclimate3109 CrossRefGoogle Scholar
  62. Sankaran M, Ratnam J, Hanan NP (2004) Tree-grass coexistence in savannas revisited - insights from an examination of assumptions and mechanisms invoked in existing models. Ecol Lett 7(6):480–490.  https://doi.org/10.1111/j.1461-0248.2004.00596.x CrossRefGoogle Scholar
  63. Sankaran M, Hanan NP, Scholes RJ, Ratnam J, Augustine DJ, Cade BS, Gignoux J, Higgins SI, le Roux X, Ludwig F, Ardo J, Banyikwa F, Bronn A, Bucini G, Caylor KK, Coughenour MB, Diouf A, Ekaya W, Feral CJ, February EC, Frost PGH, Hiernaux P, Hrabar H, Metzger KL, Prins HHT, Ringrose S, Sea W, Tews J, Worden J, Zambatis N (2005) Determinants of woody cover in African savannas. Nature 438(7069):846–849.  https://doi.org/10.1038/nature04070 CrossRefPubMedGoogle Scholar
  64. Scheiter S, Higgins SI (2007) Partitioning of root and shoot competition and the stability of savannas. Am Nat 170(4):587–601.  https://doi.org/10.1086/521317 CrossRefPubMedGoogle Scholar
  65. Scheiter S, Langan L, Higgins SI (2013) Next-generation dynamic global vegetation models: learning from community ecology. New Phytol 198(3):957–969.  https://doi.org/10.1111/nph.12210 CrossRefPubMedGoogle Scholar
  66. Scholes RJ, Archer SR (1997) Tree-grass interactions in savannas. Annu Rev Ecol Syst 28(1):517–544.  https://doi.org/10.1146/annurev.ecolsys.28.1.517 CrossRefGoogle Scholar
  67. Snell RS, Cowling SA, Smith B (2013) Simulating regional vegetation-climate dynamics for middle America: tropical versus temperate applications. Biotropica 45(5):567–577.  https://doi.org/10.1111/btp.12054 CrossRefGoogle Scholar
  68. Soliveres S, Eldridge DJ (2014) Do changes in grazing pressure and the degree of shrub encroachment alter the effects of individual shrubs on understorey plant communities and soil function? Funct Ecol 28(2):530–537.  https://doi.org/10.1111/1365-2435.12196 CrossRefPubMedPubMedCentralGoogle Scholar
  69. Soliveres S, Maestre FT, Eldridge DJ, Delgado-Baquerizo M, Quero JL, Bowker MA, Gallardo A (2014) Plant diversity and ecosystem multifunctionality peak at intermediate levels of woody cover in global drylands. Glob Ecol Biogeogr 23(12):1408–1416.  https://doi.org/10.1111/geb.12215 CrossRefPubMedPubMedCentralGoogle Scholar
  70. Stevens N, Erasmus BFN, Archibald S, Bond WJ (2016) Woody encroachment over 70 years in South African savannahs: overgrazing, global change or extinction aftershock? Philos Trans R Soc Lond B Biol Sci 371(1703):20150437.  https://doi.org/10.1098/rstb.2015.0437 CrossRefPubMedPubMedCentralGoogle Scholar
  71. Synodinos AD, Tietjen B, Jeltsch F (2015) Facilitation in drylands: modeling a neglected driver of savanna dynamics. Ecol Model 304:11–21.  https://doi.org/10.1016/j.ecolmodel.2015.02.015 CrossRefGoogle Scholar
  72. Tainton N (1999) Veld management in South Africa. University of Natal Press, PietermaritzburgGoogle Scholar
  73. Tietjen B (2016) Same rainfall amount different vegetation—how environmental conditions and their interactions influence savanna dynamics. Ecol Model 326:13–22.  https://doi.org/10.1016/j.ecolmodel.2015.06.013 CrossRefGoogle Scholar
  74. Tietjen B, Zehe E, Jeltsch F (2009) Simulating plant water availability in dry lands under climate change: a generic model of two soil layers. Water Resour Res 45(1):1–14.  https://doi.org/10.1029/2007wr006589 CrossRefGoogle Scholar
  75. Tietjen B, Jeltsch F, Zehe E, Classen N, Groengroeft A, Schiffers K, Oldeland J (2010) Effects of climate change on the coupled dynamics of water and vegetation in drylands. Ecohydrology 3:226–237.  https://doi.org/10.1002/eco.70 CrossRefGoogle Scholar
  76. United Nations Environment Programme (1992) World atlas of desertification. Edward Arnold, LondonGoogle Scholar
  77. Ustin SL, Gamon JA (2010) Remote sensing of plant functional types. New Phytol 186(4):795–816.  https://doi.org/10.1111/j.1469-8137.2010.03284.x CrossRefPubMedGoogle Scholar
  78. Van Auken OW (2000) Shrub invasions of North American semiarid grasslands. Annu Rev Ecol Syst 31(1):197–215.  https://doi.org/10.1146/annurev.ecolsys.31.1.197 CrossRefGoogle Scholar
  79. Vesk PA, Leishman MR, Westoby M (2004) Simple traits do not predict grazing response in Australian dry shrublands and woodlands. J Appl Ecol 41(1):22–31.  https://doi.org/10.1111/j.1365-2664.2004.00857.x CrossRefGoogle Scholar
  80. Walter H (1954) Die Verbuschung, eine Erscheinung der subtropischen savannengebiete, und ihre ökologischen ursachen. Vegetatio 5(1):6–10.  https://doi.org/10.1007/BF00299544 CrossRefGoogle Scholar
  81. Weiss L, Jeltsch F (2015) The response of simulated grassland communities to the cessation of grazing. Ecol Model 303:1–11.  https://doi.org/10.1016/j.ecolmodel.2015.02.002 CrossRefGoogle Scholar
  82. Weiss L, Pfestorf H, May F, Körner K, Boch S, Fischer M, Müller J, Prati D, Socher SA, Jeltsch F (2014) Grazing response patterns indicate isolation of semi-natural European grasslands. Oikos 123(5):599–612.  https://doi.org/10.1111/j.1600-0706.2013.00957.x CrossRefGoogle Scholar
  83. Westoby M, Walker B, Noy-Meir I (1989) Opportunistic management for rangelands not at equilibrium. J Range Manag 42(4):266–274.  https://doi.org/10.2307/3899492 CrossRefGoogle Scholar
  84. Wesuls D, Oldeland J, Dray S (2012) Disentangling plant trait responses to livestock grazing from spatio-temporal variation: the partial RLQ approach. J Veg Sci 23(1):98–113.  https://doi.org/10.1111/j.1654-1103.2011.01342.x CrossRefGoogle Scholar
  85. Wesuls D, Pellowski M, Suchrow S, Oldeland J, Jansen F, Dengler J (2013) The grazing fingerprint: modelling species responses and trait patterns along grazing gradients in semi-arid Namibian rangelands. Ecol Indic 27:61–70.  https://doi.org/10.1016/j.ecolind.2012.11.008 CrossRefGoogle Scholar
  86. Wiegand K, Saltz D, Ward D (2006) A patch-dynamics approach to savanna dynamics and woody plant encroachment—insights from an arid savanna. Perspect Plant Ecol Evol Syst 7(4):229–242.  https://doi.org/10.1016/j.ppees.2005.10.001 CrossRefGoogle Scholar
  87. Williams RJ, Duff GA, Bowman DMJS, Cook GD (1996) Variation in the composition and structure of tropical savannas as a function of rainfall and soil texture along a large-scale climatic gradient in the Northern Territory, Australia. J Biogeogr 23(6):747–756.  https://doi.org/10.1111/j.1365-2699.1996.tb00036.x CrossRefGoogle Scholar

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Authors and Affiliations

  1. 1.Plant Ecology and Nature ConservationUniversity of PotsdamPotsdamGermany
  2. 2.Biodiversity and Ecological Modelling, Institute of BiologyFreie Universität BerlinBerlinGermany
  3. 3.Dahlem Center of Plant Sciences (DCPS)Freie Universität BerlinBerlinGermany
  4. 4.Berlin-Brandenburg Institute of Advanced Biodiversity Research (BBIB)BerlinGermany

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