Avicennia Marina around Qatar: Tree, Seedling and Pneumatophore Densities in Natural and Planted Mangroves using Remote Sensing

Based on satellite images from all study sites along the east coast of Qatar, natural mangroves cover an area of 797.6 ha while planted stands cover 182.9 ha. On the west coast planted mangroves cover a small area of about 1 ha only, probably due to high salinity of seawater and contaminated sediments. The density of Avicennia marina trees in natural mangroves, at the upper tidal level is about 2800/ha, and slightly higher at the middle mangroves (about 3050/ha). In general after several replanting works over the past 23 years, planted mangroves also showed robust stands, with tree density ranging from 1,100/ha to 2,100/ha. However on the west coast tree density of planted mangroves is very low at 200/ha and restricted only to the middle tidal zone. In natural mangroves tree height ranges from 1 to 6m while in planted stands, from 1 to 3m only. On the west coast, the mangroves are stunted, with maximum tree height of 1m, probably due to high seawater salinity especially in summer where it can reach 59.1. Seedling density is also high (ranging from about 933/ha to 1,466/ha) in natural and planted mangroves on the east coast, but absent in planted stand on the west coast. On the east coast natural mangroves produced abundant pneumatophores, with density ranging from 86/ m2 to 516/ m2 while in planted mangroves the density is lower, and ranges from 88/m2 to 308/ m2. Planted mangroves performed poorly on the west coast with low pneumatophore density (30/m2). In general pneumatophore density is higher in the middle mangroves than in the upper mangroves to facilitate efficient gaseous exchange during low tide.