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Importance of nurse logs as a substrate for the regeneration of pioneer tree species on Barro Colorado Island, Panama

  • Evelyn Sanchez (a1), Rachel Gallery (a2) and James W. Dalling (a1) (a2) (a3)

Fallen tree trunks (‘nurse logs’) are important recruitment sites for trees in temperate forest, however nurse log use is seldom reported in tropical forests. We predicted that logs should be important for the regeneration of small-seeded tropical pioneer species because surface leaf litter and competition with established vegetation reduces the establishment success of these species from soil seed banks. In a survey on Barro Colorado Island, Panama, we found that pioneer seedlings were present on logs in 40 of 95 recent treefall gaps. In gaps where seedlings were present on logs, seedling density was not significantly different from adjacent areas of soil. However, species composition was significantly different; logs were disproportionately colonized by smaller-seeded and wind-dispersed species. In growing-house experiments using 12 species, we found that wood substrate had little effect on seed germination. In contrast, seedling growth was 50% lower on decayed wood than soil. Furthermore, species growth rates on wood were not significantly correlated with growth rates in soil (df = 10, r = 0.48). If establishment on logs eventually leads to recruitment to the forest canopy, then logs may promote the maintenance of diversity by favouring a different group of species from those that recruit in soil.

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ANDERSON, L. J. & WINTERTON, A. J. 1996. Germination as a determinant of seedling distributions among natural substrates in Picea engelmannii (Pinaceae) and Abies lasiocarpa (Pinaceae). American Journal of Botany 83:112117.
BROKAW, N. V. L. 1982. The definition of treefall gaps and its effect on measures of forest dynamics. Biotropica 14:158160.
BROKAW, N. V. L. 1985. Gap-phase regeneration in a tropical forest. Ecology 66:682687.
BROKAW, N. V. L. 1987. Gap phase regeneration of three pioneer tree species in a tropical forest. Journal of Ecology 75:919.
BRUNDRETT, M., BOUGHER, N., DELL, B., GROVE, T. & MALAJCZUK, N. 1996. Working with mycorrhizas in forestry and agriculture. ACIAR Monograph 32. Australian Centre for International Agricultural Research, Canberra. 374 pp.
CHRISTIE, D. A. & ARMESTO, J. J. 2003. Regeneration microsites and tree species coexistence in temperate rain forests of Chiloé Island, Chile. Journal of Ecology 91:776784.
CHRISTY, E. J. & MACK, R. N. 1984. Variation in demography of juvenile Tsuga heterophylla across the substratum mosaic. Journal of Ecology 72:7591.
COLWELL, R. K., MAO, C. X. & CHANG, J. 2004. Interpolating, extrapolating, and comparing incidence-based species accumulation curves. Ecology 85:27172727.
COOMES, D. A., ALLEN, R. B., BENTLEY, W. A., BURROWS, L. E., CANHAM, C. D., FAGAN, L., FORSYTH, D. M., GAXIOLA-ALCANTAR, A., PARFITT, R. L., RUSCOE, W. A., WARDLE, D. A., WILSON, D. J. & WRIGHT, E. F. 2005. The hare, the tortoise and the crocodile: the ecology of angiosperm dominance, conifer persistence and fern filtering. Journal of Ecology 93:918935.
CROAT, T. R. 1978. Flora of Barro Colorado Island. Stanford University Press, Stanford. 943 pp.
DALLING, J. W. & HUBBELL, S. P. 2002. Seed size, growth rate and gap microsite conditions as determinants of recruitment success for pioneer species. Journal of Ecology 90:557568.
DALLING, J. W., SWAINE, M. D. & GARWOOD, N. C. 1997. Soil seed bank community dynamics in seasonally moist lowland tropical forest, Panama. Journal of Tropical Ecology 13: 659680.
DALLING, J. W., HUBBELL, S. P. & SILVERA, K. 1998. Seed dispersal, seedling emergence and gap partitioning in gap-dependent tropical tree species. Journal of Ecology 86:674689.
DALLING, J. W., MULLER-LANDAU, H. C., WRIGHT, S. J. & HUBBELL, S. P. 2002. Role of dispersal in the recruitment limitation of neotropical pioneer trees. Journal of Ecology 90:714727.
DAWS, M. I., CRABTREE, L. M., DALLING, J. W., MULLINS, C. E. & BURSLEM, D. F. R. P. 2008. Germination responses to water potential in neotropical pioneers suggest larger seeded species take more risks. Annals of Botany 108:945951.
ENGELBRECHT, B. M. J., DALLING, J. W., PEARSON, T. R. H., WOLF, R. L., GALVEZ, D. A., KOEHLER, T., TYREE, M. T. & KURSAR, T. A. 2006. Short dry spells in the wet season increase mortality of tropical pioneer seedlings. Oecologia 148:258269.
ERIKSSON, O. & EHRLÉN, J. 1992. Seed and microsite limitation of recruitment in plant populations. Oecologia 91:360364.
GRAY, A. N. & SPIES, T. A. 1997. Microsite controls on tree seedling establishment in conifer forest canopy gaps. Ecology 78:24582473.
HARMON, M. E. 1989. Retention of needles and seeds on logs in Picea sitchensis–Tsuga heterophylla forests of coastal Oregon and Washington. Canadian Journal of Botany 67:18331837.
HARMON, M. E. & FRANKLIN, J. F. 1989. Tree seedlings on logs in Picea–Tsuga forests of Oregon and Washington. Ecology 70:4859.
HARTSHORN, G. S. 1980. Neotropical forest dynamics. Biotropica 12 (Supplement):2330.
HOFGAARD, A. 1993. Structure and regeneration patterns in a virgin Picea abies forest in northern Sweden. Journal of Vegetation Science 4:601608.
HUBBELL, S. P., FOSTER, R. B., O'BRIEN, S. T., HARMS, K. E., CONDIT, R. & WECHSLER, B. 1999. Light-gap disturbances, recruitment limitation, and tree diversity in a neotropical forest. Science 283:554557.
JOHNSON, D. W., WALKER, R. F. & BALL, J. T. 1995. Lessons from lysimeters: soil N release from disturbance compromises controlled environment study. Ecological Applications 5:395400.
KENNEDY, D. N. & SWAINE, M. D. 1992. Germination and growth of colonizing species in artificial gaps of different sizes in dipterocarp rain forest. Philosophical Transactions of the Royal Society, Series B Biological Sciences 335:357367.
KNECHTEL, A. 1903. Natural reproduction in the Adirondack forests. Journal of Forestry 1:5055.
LACK, A. J. 1991. Dead logs as a substrate for rain forest trees in Dominica. Journal of Tropical Ecology 7:401405.
LAMAN, T. G. 1995. Ficus stupenda germination and establishment in a Bornean rain forest canopy. Ecology 76:26172626.
LAWTON, R. O. & PUTZ, F. E. 1988. Natural disturbance and gap-phase regeneration in a wind-exposed tropical cloud forest. Ecology 69:764777.
LUSK, C. H. 1995. Seed size, establishment sites and species coexistence in a Chilean rainforest. Journal of Vegetation Science 6:249256.
LUSK, C. H. & OGDEN, J. 1992. Age structure and dynamics of podocarp-broadleaf forest in Tongariro National Park, New Zealand. Journal of Ecology 80:379393.
MARX, L. & WALTERS, M. B. 2006 . Effects of N supply and wood species on Tsuga canadensis and Betula alleghaniensis seedling growth on decaying wood. Canadian Journal of Forest Research 36:28732884.
McCULLOUGH, H. A. 1948. Plant succession of decaying logs in a virgin spruce-fur forest. Ecology 29:508513.
MOLOFSKY, J. & AUGSPURGER, C. K. 1992. The effect of leaf litter on early seedling establishment in a tropical forest. Ecology 73:6877.
MURRAY, K. G. & GARCIA, J. M. 2002. Contributions of seed dispersal and demography to recruitment limitation in a Costa Rica cloud forest. Pp. 323338 in Levey, D. J., Silva, W. R. & Galetti, M. (eds). Seed dispersal and frugivory: ecology, evolution and conservation. CAB International, Wallingford.
O'HANLON-MANNERS, D. & KOTANEN, P. 2004. Logs as refuges from fungal pathogens for seeds of eastern hemlock (Tsuga canadensis). Ecology 85:284289.
PETERSON, C. J. & HAINES, B. L. 2000. Early successional patterns and potential facilitation of woody plant colonization by rotting logs in premontane Costa Rican pastures. Restoration Ecology 8:361369.
PUTZ, F. E. 1983. Treefall pits and mounds, buried seeds, and the importance of soil disturbance to pioneer trees on Barro Colorado Island, Panama. Ecology 64:1169–1074.
PUTZ, F. E. & APPANAH, S. 1987. Buried seeds, newly dispersed seeds, and the dynamics of a lowland forest in Malaysia. Biotropica 19:326339.
RAND, A. S. & RAND, W. M. 1982. Variation in rainfall on Barro Colorado Island. Pp. 4766 in Leigh, E., Rand, A. & Windsor, D. (eds). The ecology of a tropical forest. Smithsonian Institution Press, Washington, DC.
SANTIAGO, L. S. 2000. Use of coarse woody debris by the plant community of a Hawaiian montane cloud forest. Biotropica 32:633641.
SCHNITZER, S. A., DALLING, J. W. & CARSON, W. P. 2000. The impact of lianas on tree regeneration in tropical forest canopy gaps: evidence for an alternative pathway of gap-phase regeneration. Ecology 82:913919.
SHAM, P. C. & CURTIS, D. 1995. Monte Carlo tests for associations between disease and alleles at highly polymorphic loci. Annals of Human Genetics 59:97105.
SLOCUM, M. G. 2000. Logs and fern patches as recruitment sites in a tropical pasture. Restoration Ecology 8:408413.
SWAINE, M. D. & HALL, J. B. 1983. Early succession on cleared forest land in Ghana. Journal of Ecology 71:601627.
TAKAHASHI, M., SAKAI, Y., OOTOMO, R. & SHIOZAKI, M. 2000. Establishment of tree seedlings and water-soluble nutrients in coarse woody debris in an old-growth Picea-Abies forest in Hokkaido, northern Japan. Canadian Journal of Forest Research 30:11481155.
TAYLOR, R. F. 1935. Available nitrogen as a factor influencing the occurrences of Sitka spruce and western hemlock seedlings in the forests of southeastern Alaska. Ecology 16:580642.
TRAN, T. S. & SIMARD, R. R. 1993. Mehlich III extractable elements. Pp. 4350 in Carter, M. R. (ed.). Soil sampling and methods of analysis. Lewis, Boca Raton.
VAN DER MEER, P. J., STERCK, F. J. & BONGERS, F. 1998. Tree seedling performance in canopy gaps in a tropical rain forest at Nourages, French Guiana. Journal of Tropical Ecology 14:119137.
WANG, G. G. & KEMBELL, K. J. 2005. Balsam fir and white spruce seedling recruitment in response to understory release, seedbed type, and litter exclusion in trembling aspen stands. Canadian Journal of Forest Research 35:667673.
ZHONG, J. & VAN DER KAMP, B. J. 1999. Pathology of conifer seed and timing of germination in high elevation subalpine fir and Engelmann spruce forests in the southern interior of British Columbia. Canadian Journal of Forest Research 29:187193.
ZIELONKA, T. & PIATEK, G. 2001. Norway spruce regeneration on decaying logs in subalpine forests in the Tatra National Park. Polish Botanical Journal 46:251260.
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