Showing papers by "Daniel M. Alongi published in 2014"

Carbon Cycling and Storage in Mangrove Forests

Abstract: Mangroves are ecologically and economically important forests of the tropics. They are highly productive ecosystems with rates of primary production equal to those of tropical humid evergreen forests and coral reefs. Although mangroves occupy only 0.5% of the global coastal area, they contribute 10–15% (24 Tg C y−1) to coastal sediment carbon storage and export 10–11% of the particulate terrestrial carbon to the ocean. Their disproportionate contribution to carbon sequestration is now perceived as a means for conservation and restoration and a way to help ameliorate greenhouse gas emissions. Of immediate concern are potential carbon losses to deforestation (90–970 Tg C y−1) that are greater than these ecosystems' rates of carbon storage. Large reservoirs of dissolved inorganic carbon in deep soils, pumped via subsurface pathways to adjacent waterways, are a large loss of carbon, at a potential rate up to 40% of annual primary production. Patterns of carbon allocation and rates of carbon flux in mangrove f...

Mangrove community structure and regeneration potential on a rapidly expanding, river delta in Java

Abstract: Mangroves in rapidly expanding Southeast Asian river deltas form floristically simple zones dominated by a few highly regenerative species adaptable or tolerant to rapid sedimentation and extensive river flooding The size class distribution, community composition and spatial structure of five representative mangrove forests in the rapidly expanding Cimanuk river delta on Java were determined These deltaic forests are species-poor (eight true mangrove species) and spatially segregated into three distinct floristic zones: (1) a fringing, low intertidal zone co-dominated by Avicennia marina and A officinalis, with less abundant Bruguiera parviflora, Rhizophora apiculata, and R mucronata; (2) a zone transitional between the low and mid intertidal in which Avicennia and Rhizophora spp co-dominate; and (3) a mid intertidal zone dominated by R mucronata and R apiculata Numerically dominated by seedlings (52,500–73,500 seedlings ha−1) and saplings (5,268–5,660 saplings ha−1), all five forests are relatively young and actively regenerating Positive correlations of tree stem diameter and tree height with soil organic matter and P concentrations, salinity, the soil C/N ratio, pH, and silt/clay composition highlight the importance of soil factors in sustaining forest growth The low diversity and relative structural simplicity of these rapidly growing and regenerating forests may be attributed to adaptation or tolerance to flooding and the rapid sedimentation and seaward expansion of the delta

Mangrove Forests of Timor-Leste: Ecology, Degradation and Vulnerability to Climate Change

Abstract: Mangrove forests occupy a relatively small area (1,300 ha) of the coastal zone of Timor-Leste, being composed of fringing stands of relatively few species (a total of 19 true mangrove species) inhabiting sand-dominated deposits in small lagoons along the south coast and sheltered embayments along the north coast. Despite their small size and disjunct distribution these mangroves are heavily used as a source of food, and wood for housing and fuel, and have been used as burial sites during past episodes of violence during occupation. Links between mangroves and fisheries offshore are uncertain, but it is clear that net canopy production is low, equivalent to the mangrove forests in other dry tropical zones. Timorese mangroves face a very uncertain future in light of their small, fragmented distribution, heavy human encroachment, and forecasted rise in sea level.