Cold tolerance of photosynthesis as a determinant of tree species regeneration patterns in an evergreen temperate forest
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Niche partitioning of light among seedling species is a key mechanism supporting coexistence in forests. Species sort along light gradients through direct responses to light and through indirect responses mediated by other environmental factors. Canopy gaps in temperate evergreen rainforests experience sub-zero temperatures and thus gap-dependent species are vulnerable to cold photoinhibition from exposure to high light at low temperatures. We used a shadehouse experiment to test two hypotheses: (1) that gap-dependent species are resistant to cold photoinhibition; and (2) that gap-dependence observed in the field may be driven by the interaction between high light and low temperatures. Specifically, we predicted that some species restricted to shade in the field are excluded from gaps because of low resistance to cold photoinhibition. Gap dependence of angiosperm and conifer seedlings was estimated from expert opinion, and from experimental growth and survival responses to light treatments representing a forest understorey and forest gap. Additional seedlings were used to evaluate resistance to cold photoinhibition (sub-zero temperatures at dawn). Gap-dependent species were resistant to cold photoinhibition. Our second hypothesis was supported by Beilschmiedia tawa (Lauraceae), which had low resistance to photoinhibition, a strong positive growth response to the light treatments, and is restricted to shade in the field. Seedling regeneration niches in temperate rainforest are shaped in part by the interaction between light and low temperatures, and this interaction will be crucial for determining seedling responses to climate warming.
KeywordsChlorophyll fluorescence Climate change New Zealand Plant functional trait Regeneration niche Shade tolerance
We thank Ellen Cieraad, Tahae Doherty, Chris Morse, Rowan Buxton and Gaye Rattray for assistance; Matt McGlone, Norm Mason and Duane Peltzer for reviews; and the NZ Ministry of Business, Innovation and Employment for funding.
- Dehlin H, Peltzer DA, Allison VJ, Yeates GW, Nilsson MC, Wardle DA (2008) Tree seedling performance and below-ground properties in stands of invasive and native tree species. NZ J Ecol 32:67–79Google Scholar
- Enright NJ, Ogden J (1995) The southern conifers: a synthesis. In: Enright NJ, Hill RS (eds) Ecology of the southern conifers. Melbourne University Press, Carlton, pp 271–287Google Scholar
- Kelly D (1987) Slow recovery of Beilschmiedia tawa after severe frosts in inland Taranaki, New Zealand. NZ J Ecol 10:137–140Google Scholar
- 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, Oxford, pp 331–348Google Scholar
- Lusk CH, Duncan RP, Bellingham PJ (2009) Light environments occupied by conifer and angiosperm seedlings in a New Zealand podocarp–broadleaved forest. NZ J Ecol 33:83–89Google Scholar
- McGlone MS, Richardson SJ, Jordan GJ (2010) Comparative biogeography of New Zealand trees: species richness, height, leaf traits and range sizes. NZ J Ecol 34:137–151Google Scholar
- MfE (2008) Climate change effects and impacts assessment: a guidance manual for local government in New Zealand. Ministry for the Environment, WellingtonGoogle Scholar
- Öquist G, Greer DH, Ögren E (1987) Light stress at low temperature. In: Kyle DJ, Osmond CB, Arntzen CJ (eds) Photoinhibition. Elsevier Science, Amsterdam, pp 67–87Google Scholar
- Peltzer DA, Allen RB, Rogers GM (2005) Dieback and recruitment of the forest dominants Nothofagus fusca and Libocedrus bidwillii, central North Island, New Zealand, vol 255. Department of Conservation, Science for Conservation, Wellington, p 33Google Scholar