The effect of nutrient enrichment on growth, photosynthesis and hydraulic conductance of dwarf mangroves in Panamá

Abstract

Summary1. Dwarf stands of the mangrove Rhizophora mangle L. are extensive in the Caribbean. We fertilized dwarf trees in Almirante Bay, Bocas del Toro Province, north-eastern Panamá with nitrogen (N) and phosphorus (P) to determine (1) if growth limitations are due to nutrient deficiency; and (2) what morphological and/or physiological factors underlie nutrient limitations to growth. 2. Shoot growth was 10-fold when fertilized with P and twofold with N fertilization, indicating that stunted growth of these mangroves is partially due to nutrient deficiency. 3. Growth enhancements caused by N or P enrichment could not be attributed to increases in photosynthesis on a leaf area basis, although photosynthetic nutrient-use efficiency was improved. The most dramatic effect was on stem hydraulic conductance, which was increased sixfold by P and 2·5-fold with N enrichment. Fertilization with P enhanced leaf and stem P concentrations and reduced C : N ratio, but did not alter leaf damage by herbivores. 4. Our findings indicate that addition of N and P significantly alter tree growth and internal nutrient dynamics of mangroves at Bocas del Toro, but also that the magnitude, pattern and mechanisms of change will be differentially affected by each nutrient.

Nutrient Limitation in Central Red Sea Mangroves

“…We assessed the nutrient status of mangrove stands in the Red Sea by examining the concentrations of nitrogen, phosphorous and iron, the nutrients most often reported to limit mangrove growth (Feller, 1995;Koch and Snedaker, 1997;Feller et al, 2003a,b;Lovelock et al, 2004Lovelock et al, , 2006Naidoo, 2009;Alongi, 2011). We analyzed nutrient concentrations in mature leaves as well as the stoichiometric ratios of the nutrients to carbon.…”

“…Indeed, low availability of nitrogen, phosphorus, and iron has been suggested as the cause for the absence of mangroves along shorelines that are otherwise suitable for mangrove growth (Sato et al, 2011). Mangrove fertilization experiments have demonstrated site-specific nutrient limitation of nitrogen and phosphorous (Feller, 1995;Koch and Snedaker, 1997;Feller et al, 2003a,b;Lovelock et al, 2004Lovelock et al, , 2006Naidoo, 2009;Alongi, 2011), whereas an experimental study conducted on mangroves in north Queensland, Australia, demonstrated iron deficiency (Alongi, 2010). Previous work has not considered these three nutrients together, which is the focus of this work.…”

“…Mangroves often grow in river mouths and deltaic areas, where they receive abundant nutrient supply from riverine discharge, but they also grow in areas devoid of riverine inputs, such as carbonate shores in the Caribbean and islands in South East Asia and the Red Sea, where they are often nutrient limited and, as a result, have a dwarf stature (Feller, 1995;Duarte et al, 1998;Lovelock et al, 2004). In particular, nitrogen, phosphorus, or iron is often reported to limit mangrove growth, while other essential nutrients are abundant in seawater, making them available to mangroves (Alongi, 2011).…”

Concentrations and Fractionation of Carbon, Iron, Sulfur, Nitrogen and Phosphorus in Mangrove Sediments Along an Intertidal Gradient (Semi-Arid Climate, New Caledonia)

“…N and P limitations may be directly linked to soil elevation and nutrients inputs frequencies by tides or river along the existing zonation [49][50][51]. Mangrove trees on river banks and on the shoreline can form a strong and dense fringing stand, while mangroves developing at higher elevations usually form dwarf stands [52] as it is the case in New Caledonia.…”

Proceedings of the Smithsonian Marine Science Symposium

“…At Bocas, fringe and scrub sites were located on three islands (San Cristobal, Solarte, Isla Popa) in Almirante Bay and the Chiriqui Lagoon in a vast network of mangrove islands and mainland peninsulas covering approximately 2,885 km 2 (De Croz, 1993;Guzman and Guevara, 1998;Guzman et al, 2005;Lovelock et al, 2004Lovelock et al, , 2005. Here, mangroves occurred adjacent to tropical rainforests and grew on peat approximately 5 m deep atop ancient coral reef limestone (Phillips and Bustin, 1996;Phillips et al, 1997).…”