Abstract
In this study I investigated the effects of the extreme, 1997/98 El Niño related drought on tree mortality and understorey light conditions of logged and unlogged tropical rain forest in the Indonesian province of East Kalimantan (Borneo). My objectives were to test (1) whether drought had a significant effect on tree mortality and understorey light conditions, (2) whether this effect was greater in logged than in undisturbed forest, (3) if the expected change in tree mortality and light conditions had an effect on Macaranga pioneer seedling and sapling densities, and (4) which (a)biotic factors influenced tree mortality during the drought. The 1997/1998 drought led to an additional tree mortality of 11.2, 18.1, and 22.7% in undisturbed, old logged and recently logged forest, respectively. Mortality was highest in logged forests, due to extremely high mortality of pioneer Macaranga trees (65.4%). Canopy openness was significantly higher during the drought than during the non-drought year (6.0, 8.6 and 10.4 vs 3.7, 3.8 and 3.7 in undisturbed, old logged and recently logged forest, respectively) and was positively correlated with the number of dead standing trees. The increase in light in the understorey was accompanied by a 30 to 300-fold increase in pioneer Macaranga seedling densities. Factors affecting tree mortality during drought were (1) tree species successional status, (2) tree size, and (3) tree location with respect to soil moisture. Tree density and basal area per surface unit had no influence on tree mortality during drought. The results of this study show that extreme droughts, such as those associated with El Niño events, can affect the tree species composition and diversity of tropical forests in two ways: (1) by disproportionate mortality of certain tree species groups and tree size classes, and (2) by changing the light environment in the forest understorey, thereby affecting the recruitment and growth conditions of small and immature trees.
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References
Asdak C, Jarvis PG, Gardingen P van (1998a) Evaporation of intercepted precipitation based on an energy balance in unlogged and logged forest areas of Central Kalimantan, Indonesia. Agric For Meteorol 92:173–180
Asdak C, Jarvis PG, Gardingen P van, Fraser A (1998b) Rainfall interception loss in unlogged and logged forest areas of Central Kalimantan, Indonesia. J Hydrol 206:237–244
Chappell NA, Bidin K, Tych W (2001) Modelling rainfall and canopy controls on net-precipitation beneath selectively-logged tropical forest. Plant Ecol 153:215–229
Curran LM, Caniago I, Paoli GD, Astianti D, Kusneti M, Leighton M, Nirarita CE, Haeruman H (1999) Impact of El Niño and logging on canopy tree recruitment in Borneo. Science 286:2184–2188
Daws MI, Mullins C, Burslem D, Paton R, Dalling J (2002) Topographic position affects the water regime in a semideciduous tropical forest in Panama. Plant Soil 238:79–90
Enfield DB (1992) Historical and prehistorical overview of El Niño/Southern Oscillation. In: Diaz HF, Margraf V (eds) El Niño: historical and paleoclimatic aspects of the Southern Oscillation. Cambridge University Press, Cambridge, pp 95–117
Gilbert GS, Harms KE, Hamill DN, Hubbell SP (2001) Effects of seedlings size, El Niño drought, seedling density, and distance to nearest conspecific adult on 6-year survival of Ocotea whitei seedlings in Panama. Oecologia 127:509–516
Hacke UG, Sperry JS, Pockman WT, Davis SD, McCulloh KA (2001) Trends in wood density and structure are linked to prevention of xylem implosion by negative pressure. Oecologia 126:457–461
Harger JRE (1995) Air-temperature variations and ENSO effects in Indonesia, The Philippines and El Salvador. ENSO patterns and changes from 1866–1993. Atmos Environ 29:1919–1942
Meinzer FC (2003) Functional convergence in plant responses to the environment. Oecologia 134:1–11
Nakagawa M, Tanaka K, Nakashizuka T, Ohkubo T, Kato T, Maeda T, Sato K, Migughi H, Nagamasu H, Ogino K, Teo S, Hamid AA, Seng LH (2000) Impact of severe drought associated with the 1997–1998 El Niño in a tropical forest in Sarawak. J Trop Ecol 16:355–367
Nepstad DC, Decarvalho CR, Davidson EA, Jipp PH, Lefebre PA, Negreiros GH, Dasilva ED, Stone TA, Trumbore SE, Vieira S (1994) The role of deep roots in the hydrological and carbon cycles of Amazonian forests and pastures. Nature 372:666–669
Nieuwstadt MGL van (2002) Trail by fire: postfire development of a tropical dipterocarp forest. PhD thesis, Utrecht University
Potts MD (2003) Drought in a Bornean everwet rain forest. J Ecol 91:467–474
RePPProT (Regional Physical Planning Programme for Transmigration) (1987) Review of phase I. results East and South Kalimantan. vol 2, Annexes 3–6. Departemen Transmigrasi, Jakarta
Salafsky N (1994) Drought in the rain forest: effects of the 1991 El Niño-Southern oscillation event on a rural economy in West Kalimantan, Indonesia. Climatic Change 27:373–396
Slik JWF, Priyono, Welzen PC van (2000) Key to the Macaranga Thou. and Mallotus Lour. species (Euphorbiaceae) of East Kalimantan, Indonesia. Gardens Bull Singapore 52:11–87
Slik JWF, Verburg RW, Keßler PJA (2002) Effects of fire and logging on the tree species composition of lowland dipterocarp forest in East Kalimantan, Indonesia. Biodivers Conserv 11:85–98
Slik JWF, Keßler PJA, Welzen van PC (2003a) Macaranga and Mallotus species (Euphorbiaceae) as indicators for disturbance in the mixed lowland dipterocarp forest of East Kalimantan (Indonesia). Ecol Indic 2:311–324
Slik JWF, Poulsen AD, Ashton PS, Cannon CH, Eichhorn KAO, Kartawinata K, Lanniari I, Nagamasu H, Nakagawa M, Nieuwstadt MGL van, Payne J, Purwaningsih, Saridan A, Sidiyasa K, Verburg RW, Webb CO, Wilkie P (2003b) A floristic analysis of the lowland dipterocarp forests of Borneo. J Biogeogr 30:1517–1531
Sokal RR, Rohlf FJ (1995) Biometry. The principles and practice of statistics in biological research. 3rd edn. Freeman, New York
Steege H ter (1996) Winphot 5: a programme to analyse vegetation indices, light and light quality for hemispherical photographs. Tropenbos Guyana Programme, Georgetown
Tudhope AW, Chilcott CP, McCulloch MT, Cook ER, Chappell J, Ellam RM, Lea DW, Lough JM, Shimmield GB (2001) Variability in the El Niño-Southern oscillation through a glacial-interglacial cycle. Science 291:1511–1517
Verburg R, Eijk-Bos C van (2003) Effects of selective logging on tree diversity, composition and plant functional type patterns in a Bornean rain forest. J Veg Sci 14:99–110
Walsh RPD (1996) Drought frequency changes in Sabah and adjacent parts of northern Borneo since the late nineteenth century and possible implications for tropical rain forest dynamics. J Trop Ecol 12:385–407
Wich SA, van Schaik CP (2000) The impact of El Niño on mast fruiting in Sumatra and elsewhere in Malesia. J Trop Ecol 16:563–577
Williamson GB, Laurance WF, Oliveira AA, Delamonica P, Gascon C, Lovejoy TE, Pohl L (2000) Amazonian tree mortality during the 1997 El Niño drought. Conserv Biol 14:1538–1542
Acknowledgements
I would like to thank the MOFEC-Tropenbos Kalimantan Project, the Forest Research Institute Samarinda, the PT-ITCI-logging concession, and the Indonesian Academy of Sciences (LIPI) for making this project possible. I am especially grateful for the help offered by Kade Sidiyasa, Tinus de Kam, Zainal Arifin, Adriansyah, Bas van Helvoort, Arbainsyah, Ambriansyah, Nyah and Paul Keßler. I thank Pieter Baas and Karl Eichhorn for critically reviewing earlier versions of this paper. This project was financed by the Dutch Foundation for the Advancement of Tropical Research (WOTRO) grant 895.100.026.
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Slik, J.W.F. El Niño droughts and their effects on tree species composition and diversity in tropical rain forests. Oecologia 141, 114–120 (2004). https://doi.org/10.1007/s00442-004-1635-y
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DOI: https://doi.org/10.1007/s00442-004-1635-y