Plant Ecology

, Volume 191, Issue 1, pp 33–45 | Cite as

High solar radiation hinders tree regeneration above the alpine treeline in northern Ecuador

  • Maaike Y. Bader
  • Isabel van Geloof
  • Max Rietkerk
Original Paper


Many tropical alpine treelines lie below their climatic potential, because of natural or anthropogenic causes. Forest extension above the treeline depends on the ability of trees to establish in the alpine environment. This ability may be limited by different factors, such as low temperatures, excess solar radiation, competition, soil properties, dispersal ability, and fires. In this paper we address the following two questions: Do trees regenerate above the present treeline, and what are the inhibiting factors for tree establishment? To answer these questions we described the spatial pattern of recent tree establishment below and above the present treeline in northern Ecuador. Also, we experimentally transplanted seedlings into the alpine vegetation (páramo) and the forest, and investigated the effect of shade, neighboring plants, and substrate on their survival. The number of naturally occurring tree sprouts (seedlings, saplings and ramets) was highest just outside the forest, and decreased with distance to the forest edge. However, only two species that were radiation-tolerant made up these high numbers, while other species were rare or absent in the páramo. In the forest, the species diversity of sprouts was high and the abundance per species was relatively low. The transplanted seedlings survived least in experimental plots without artificial shade where neighboring plants were removed. Seedling survival was highest in artificially shaded plots and in the forest. This shade-dependence of most tree species can strongly slow down forest expansion toward the potential climatic treeline. Due to the presence of radiation-tolerant species, the complete lack of forest expansion probably needs to be ascribed to fire. However, our results show that natural processes can also explain both the low position and the abruptness of tropical treelines.


Cloud forest Cold-induced photoinhibition Fire Páramo Positive feedback switch Transplantation experiment 


  1. Armand AD (1992) Sharp and gradual mountain timberlines as a result of species interaction. In: Hansen AJ, Castri FD (eds) Landscape boundaries : consequences for biotic diversity and ecological flows. Springer, New YorkGoogle Scholar
  2. Bader MY, Rietkerk M, Bregt AK in review. Vegetation structure and temperature regimes of tropical alpine treelinesGoogle Scholar
  3. Ball MC, Hodges VS, Laughlin GP (1991) Cold-induced photoinhibition limits regeneration of snow gum at tree-line. Funct Ecol 5:663–668CrossRefGoogle Scholar
  4. Barber J, Andersson B (1992) Too much of a good thing: light can be bad for photosynthesis. Trends Biochem Sci 17:61–66Google Scholar
  5. Beck E, Scheibe R, Schulze ED (1986) Recovery from fire: observations in the alpine vegetation of western Mt. Kilimanjaro (Tanzania). Phytocoenologia 14:55–77Google Scholar
  6. Beyer C (1993) Vergleichende morphologische und anatomische Untersuchungen zur Ontogonie der terrestrischen Loranthaceae. Biologie. Philipps-Universität Marburg, p. 232Google Scholar
  7. Bond WJ, Keeley JE (2005) Fire as a global ’herbivore’: the ecology and evolution of flammable ecosystems. Trends Ecol Evol 20:387–394PubMedCrossRefGoogle Scholar
  8. Callaway RM (1995) Positive interactions among plants. Bot Rev 61:306–349Google Scholar
  9. Callaway RM, Brooker RW, Choler P, Kikvidze Z, Lortie CJ, Michalet R, Paolini L, Pugnaire FL, Newingham B, Aschehoug ET, Armas C, Kikodze D, Cook BJ (2002) Positive interactions among alpine plants increase with stress. Nature 417:844–848PubMedCrossRefGoogle Scholar
  10. Camarero JJ, Gutiérrez E (2004) Pace and pattern of recent treeline dynamics: Response of ecotones to climatic variability in the Spanish Pyrenees. Clim Change 63:181–200CrossRefGoogle Scholar
  11. Choler P, Michalet R, Callaway RM (2001) Facilitation and competition on gradients in alpine plant communities. Ecology 82:3295–3308Google Scholar
  12. Close DC, Beadle CL, Brown PH, Holz GK (2000) Cold-induced photoinhibition affects establishment of Eucalyptus nitens (deane and maiden) maiden and Eucalyptus globulus labill. Trees—Struct Funct 15(1):32–41Google Scholar
  13. Cuevas JG (2000) Tree recruitment at the Nothofagus pumilio alpine timberline in Tierra del Fuego, Chile. J Ecol 88:840–855CrossRefGoogle Scholar
  14. Di Pasquale G, Marziano M, Impagliazzo S, Lubritto C, De Natale A, Bader MY accepted. The Holocene treeline in the northern Andes (Ecuador): first evidence from soil charcoal. Palaeogeogr Palaeoclimatol PalaeoecolGoogle Scholar
  15. Ellenberg H (1996) Paramos und Punas der Hochanden suedamerikas, heute grossenteils als potentielle Waelder anerkannt. Verhandlungen der Gesellschaft für Oekologie 25:17–24Google Scholar
  16. Germino MJ, Smith WK (1999) Sky exposure, crown architecture, and low-temperature photoinhibition in conifer seedlings at alpine treeline. Plant Cell Environ 22:407–415CrossRefGoogle Scholar
  17. Germino MJ, Smith WK, Resor AC (2002) Conifer seedling distribution and survival in an alpine-treeline ecotone. Plant Ecol 162:157–168CrossRefGoogle Scholar
  18. Hamilton LS, Juvik JO, Scatena FN (1995) Tropical montane cloud forests. Springer Verlag, New YorkGoogle Scholar
  19. Hemp A, Beck E (2001) Erica excelsa as a fire-tolerating component of Mt. Kilimanjaro’s forests. Phytocoenologia 31:449–475Google Scholar
  20. Hofstede R, Segarra P, Mena Vásconez P (eds) (2003) Los páramos del Mundo. Proyecto Atlas Mundial de los Páramos. Global Peatland Initiative/NC-IUCN/EcoCienciaGoogle Scholar
  21. Hofstede RGM, Chilito EJ, Sandovals EM (1995) Vegetative structure, microclimate, and leaf growth of a paramo tussock grass species, in undisturbed, burned and grazed conditions. Vegetatio 119:53–65Google Scholar
  22. Holtmeier FK (1994) Ecological aspects of climatically-caused timberline fluctuations, review and outlook. In: Beniston M (ed) Mountain environments in changing climates. Routledge, London; New York, pp 220–233Google Scholar
  23. Huner NPA, Öquist G, Sarhan F (1998) Energy balance and acclimation to light and cold. Trends Plant Sci 3:224–230Google Scholar
  24. Kessler M (1995) Present and potential distribution of Polylepis (Rosaceae) forests in Bolivia. In: Churchill SP, Balslev H, Forero E, Luteyn JL (eds) Biodiversity and conservation of Neotropical montane forests, Proceedings of the neotropical montane forest biodiversity and conservation symposium. New York Botanical Garden, pp. 281–294Google Scholar
  25. Kessler M (2000) Observations on a human-induced fire event at a humid timberline in the Bolivian Andes. Ecotropica 6:89–93Google Scholar
  26. Kessler M (2002) The “Polylepis problem”: where do we stand?. Ecotropica 8:97–110Google Scholar
  27. Kitzberger T, Steinaker DF, Veblen TT (2000) Effects of climatic variability on facilitation of tree establishment in northern Patagonia. Ecology 81:1914–1924CrossRefGoogle Scholar
  28. Körner C, Paulsen J (2004) A world-wide study of high altitude treeline temperatures. J Biogeogr 31:713–732Google Scholar
  29. Krause GH (1994) Photoinhibition induced by low temperatures. In: Baker NR, Bowyer JR (eds) Photoinhibition of photosynthesis—from molecular mechanisms to the field. BIOS Scientific Publishers, Oxford, pp 331–348Google Scholar
  30. Kuijt J (1963) On the ecology and parasitism of the Costa Rican tree mistletoe, Gaiadendron punctatum (Ruiz & Pavon) G Don. Can J Bot 41:927–936Google Scholar
  31. Kullman L (2001) 20th century climate warming and tree-limit rise in the Southern Scandes of Sweden. Ambio 30:72–80PubMedCrossRefGoogle Scholar
  32. Kupfer JA, Cairns DM (1996) The suitability of montane ecotones as indicators of global climatic change. Prog Phys Geog 20:253–272Google Scholar
  33. Laegaard S (1992) Influence of fire in the grass páramo vegetation of Ecuador. In: Balslev H, Luteyn JL (eds) Páramo. An Andean ecosystem under human influence. Academic Press, London, pp 151–170Google Scholar
  34. Long SP, Humphries S, Falkowski PG (1994) Photoinhibition of photosynthesis in nature. Annu Rev Plant Physiol Plant Mol Biol 45:633–662Google Scholar
  35. Lundmark T, Hällgren JE (1987) Effects of frost on shaded and exposed spruce and pine seedlings planted in the field. Can J For Res 17:1197–1201Google Scholar
  36. Maher EL, Germino MJ, Hasselquist NJ (2005) Interactive effects of tree and herb cover on survivorship, physiology, and microclimate of conifer seedlings at the alpine tree-line ecotone. Can J For Res 35:567–574CrossRefGoogle Scholar
  37. Miehe G, Miehe S (1994) Zur oberen Waldgrenze in tropischen Gebirge. Phytocoenologia 24:53–110Google Scholar
  38. Pugnaire FI, Haase P, Puigdefabregas J (1996) Facilitation between higher plant species in a semiarid environment. Ecology 77:1420–1426CrossRefGoogle Scholar
  39. Pugnaire FI, Luque MT (2001) Changes in plant interactions along a gradient of environmental stress. Oikos 93:42–49CrossRefGoogle Scholar
  40. Slayter RO, Noble IR (1992) Dynamics of montane treelines. In: Hansen AJ, di Castri F (eds) Landscape boundaries: consequences for biotic diversity and ecological flows. Springer, New York, pp. 346–359Google Scholar
  41. Smith WK, Germino MJ, Hancock TE, Johnson DM (2003) Another perspective on altitudinal limits of alpine timberlines. Tree Physiol 23:1101–1112PubMedGoogle Scholar
  42. Tranquillini W (1979) Physiological ecology of the Alpine timberline : tree existence at high altitudes with special reference to the European Alps. Springer, BerlinGoogle Scholar
  43. Valladares F, Pearcy RW (1997) Interactions between water stress, sun-shade acclimation, heat tolerance and photoinhibition in the sclerophyll Heteromeles arbutifolia. Plant Cell Environ 20:25–36Google Scholar
  44. van Langevelde F, van de Vijver C, Kumar L, van de Koppel J, de Ridder N, van Andel J, Skidmore AK, Hearne JW, Stroosnijder L, Bond WJ, Prins HHT, Rietkerk M (2003) Effects of fire and herbivory on the stability of savanna ecosystems. Ecology 84:337–350CrossRefGoogle Scholar
  45. Vilà M, Lloret F, Ogheri E, Terradas J (2001) Positive fire-grass feedback in Mediterranean Basin woodlands. For Ecol Manage 147:3–14CrossRefGoogle Scholar
  46. Wardle P (1985) New Zealand timberlines. 1. Growth and survival of native and introduced tree species in the Craigieburn Range, Canterbury. N Z J Bot 23:219–234Google Scholar
  47. Wardle P, Coleman MC (1992) Evidence for rising upper limits of four native New Zealand forest trees. N Z J Bot 30:303–314Google Scholar
  48. Weltzin JF, McPherson GR (1999) Facilitation of conspecific seedling recruitment and shifts in temperate savanna ecotones. Ecol Monogr 69:513–534Google Scholar
  49. Wesche K, Miehe G, Kaeppeli M (2000) The significance of fire for afroalpine ericaceous vegetation. Mt Res Dev 20:340–347CrossRefGoogle Scholar
  50. Wille M, Hooghiemstra H, Hofstede R, Fehse J, Sevink J (2002) Upper forest line reconstruction in a deforested area in northern Ecuador based on pollen and vegetation analysis. J Trop Ecol 18:409–440Google Scholar
  51. Wilson JB, Agnew ADQ (1992) Positive-feedback switches in plant communities. Adv Ecol Res 23:263–336CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media, Inc. 2006

Authors and Affiliations

  • Maaike Y. Bader
    • 1
  • Isabel van Geloof
    • 1
  • Max Rietkerk
    • 2
  1. 1.Centre for Geo-InformationWageningen UniversityWageningenThe Netherlands
  2. 2.Department Environmental Sciences, Copernicus InstituteUtrecht UniversityUtrechtThe Netherlands

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