Relationship between sediment conditions and mangrove Rhizophora apiculata seedling growth and nutrient status

Abstract

The growth rate and nutritional status of Rhizophora apiculata seedlings were analyzed across mangrove stands with different sediment composition in The Ph~lippines and Southern Thailand. Plant growth differed 10-fold and the production of new leaves, roots and branches varied between 50-and 100-fold across sites. Most (>60%) of the variance in mangrove growth rate across systems could be accounted for by differences in the nutrient concentration of the leaves, which was in turn related to the interstitial nutrient concentration and the silt plus clay content of the sediments. Nutrient-poor coarse sediments were characteristic of mangroves located in the mouths of rivers draining small watersheds, while sediments at the mouths of large rivers had high silt, clay, and nutrient contents, thus allowing the development of nutrient-sufficient. fast-growing R. apiculata seedlings. The growth of R. apiculata seedlings increased significantly when the plants grew adjacent to rivers draining areas > l 0 km2 The results provide evidence that growth of R. apiculata seedlings at the edge of the progressing mangrove forests is often nutrient limited, and that the extent of nutrient limitation depends on the delivery of silt and nutrients from the rivers The coastal zones adlacent to small ( < l 0 km2) drainage areas seem unsuitable to support adequate growth of R. apiculata seedlings, and afforestation programmes should, therefore, target mud flats adjacent to large rivers instead.

Nutrient Limitation in Central Red Sea Mangroves

“…We analyzed nutrient concentrations in mature leaves as well as the stoichiometric ratios of the nutrients to carbon. Whereas examination of leaf nutrient concentration alone does not suffice to establish nutrient budgets (Lü et al, 2012), leaf nutrient concentration robustly indicates the nutrient status of plants (Duarte, 1990(Duarte, , 1992, including mangroves (Duarte et al, 1998;Feller et al, 2003b). Moreover, leaf nutrient concentration is an important ecosystem property because it affects the decomposition rates of leaf litter (Enriquez et al, 1993).…”

“…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).…”

Differences in regeneration between hurricane damaged and clear-cut mangrove stands 25 years after clearing

“…Factors such as fruit dispersal (Clarke & Allaway, 1992;Sengupta & Middleton, 2005), predation by crab (Osborne & Smith Iii, 1990;McGuinness, 1997a) and soil properties (Ball, 1987;Duarte et al, 1998) influence the initial stage of colonisation. Although Clarke & Allaway (1992) gives a main dispersal range of a few hundred meters for Avicennia marina, according to Blanchard & Prado (1995), the main settlement of propagules of the Rhizophora mangle takes place within a few meters from the adult tree, and McGuinness (1997a) reported a main dispersal range of 3 m for Ceriops tagal in mangroves around Darwin.…”

Benthic decomposition rates and pathways in plantations of the mangrove Rhizophora apiculata in the Mekong delta, Vietnam

“…Recent studies on other mangrove forests indicate a positive relationship between rates of benthic remineralization and mangrove productivity (Alongi 2000) and differences in the specific pathways of organic matter decon~position with forest age ). These plant-microbial links are reflected in clear evidence that highly productive mangrove forests serve as sinks for many species of dissolved nutrients (Boto 1992, Kristensen et al 1995, Rivera-Monroy & Twilley 1996, Duarte et al 1998). Mangrove-microbenutrient interrelationships are complex (Boto 1992, Nedwell et al 1994) and need to be more fully understood in order to assist managers in maximizing mangrove yields.…”