ECOPHYSIOLOGY David Whitehead Æ Natalie T. Boelman Matthew H. Turnbull Æ Kevin L. Griffin David T. Tissue Æ Margaret M. Barbour John E. Hunt Æ Sarah J. Richardson Æ Duane A. Peltzer Photosynthesis and reflectance indices for rainforest species in ecosystems undergoing progression and retrogression along a soil fertility chronosequence in New Zealand Received: 3 June 2004 / Accepted: 22 February 2005 / Published online: 11 May 2005 Ó Springer-Verlag 2005 Abstract Measurements of photosynthesis at saturating irradiance and CO 2 partial pressure, A max , ‘‘adjusted’’ normalised difference vegetation index, R aNDVI , and photochemical reflectance index, R PRI , were made on trees sampled along a soil chronosequence to investigate the relationship between carbon uptake and ecosystem development in relation to nutrient availability. Mea- surements were made on the three most dominant spe- cies at six sites along the sequence in South Westland, New Zealand with soil age ranging from <6 to 120,000 years resulting from the retreat of the Franz Josef glacier. The decrease in soil phosphorus avail- ability with increasing soil age and high soil nitrogen availability at the two youngest sites, due to the presence of a nitrogen-fixing species, provided marked differences in nutrient availability. Mean A max was high at the two youngest sites, then decreased markedly with increasing site age. Analysis of the data for individual species within sites revealed separation of groups of species in the response of A max to N m and P m , suggesting complex interactions between the two nutrients. There were strong linear relationships for leaf-level R aNDVI and R PRI with A max , at high irradiance, showing that mea- surements of reflectance indices can be used to estimate A max for foliage with a range in morphology and nutrient concentrations. Notwithstanding the change in species composition from angiosperms to conifers with increasing site age, the presence of nitrogen-fixing spe- cies, the variability in foliage morphology from flat leaves to imbricate scales and a wide range in foliar nitrogen and phosphorus concentrations, there were strong positive linear relationships between site average A max and foliage nitrogen, N m , and phosphorus, P m , concentrations on a foliage mass basis. The results provide insights to interpret the regulation of photo- synthesis across natural ecosystems with marked gradi- ents in nitrogen and phosphorus availability. Keywords Leaf reflectance Æ Nitrogen Æ Phosphorus Æ Specific leaf area Æ Soil fertility Introduction Long-term development of species composition and community structure in natural ecosystems is closely related to soil nutrient availability (Vitousek et al. 1998; Walker and Moral 2003). Limited nutrient supply also results in communities consisting of species with lower foliage nutrient concentrations, lower specific leaf area (ratio of surface area to mass), lower rates of photo- synthesis and foliage that is longer-lived (Reich et al. 1997, 1999). In the early stages of forest succession fol- lowing major disturbance (progression phase), nitrogen supply is often low until nitrogen-fixing species become established, while phosphorus supply is less limiting. In the longer term (>500 years), leaching results in soils with extremely low phosphorus supply (Aerts and Communicated by Christian Koerner D. Whitehead (&) Æ M. M. Barbour Æ J. E. Hunt S. J. Richardson Æ D. A. Peltzer Landcare Research, P.O. Box 69, Lincoln, 8152, New Zealand E-mail: whiteheadD@landcareresearch.co.nz Fax: +64-3-3252418 M. H. Turnbull School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch, New Zealand N. T. Boelman Æ K. L. Griffin Department of Earth and Environmental Sciences, Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY 10964-8000, USA D. T. Tissue Department of Biology, Texas Tech University, Lubbock, TX 79409-3131, USA Oecologia (2005) 144: 233–244 DOI 10.1007/s00442-005-0068-6