YOUARESHITp!-B6*KNY<ȥkĘtdIf:MNWN>CZVkVgF>VgHTF~CB(C;ZVV/"Bڷ oFo'WϞvqJVLRĊVVPlate 22

Recording measurements of photosynthetically active radiation (PAR) from two MACAMTM SD101Q-Cos 2 PAR detectors connected to a MACAMTM Q102 radiometer. Eighty pairs of simultaneous readings of Ic (light flux density beneath the canopy) and Io (light flux density outside the canopy) were taken at each site to determine leaf area index (LAI). [Photograph: P. Mumby] Where the mangroves were too dense or low to enter then the Ic detector (measuring light flux density beneath the canopy) was attached to a 5.4 m extendible pole and inserted into the mangrove stand. A spirit level was attached to the end of the pole to ensure the detector was always vertical. All recordings of Ic were taken at waist height, approximately 0.8 m above the substrate. [Photograph: P. Mumby]

Percentage canopy cover was measured by estimating the proportion of the mirror area covered by the reflection of leaves and stems using a hand held semi-hemispherical mirror (a spherical densiometer) with a grid graticule engraved on its surface. Eighty readings were taken at each site and averaged. The spirit level was used to ensure the mirror was horizontal. [Photograph: P. Mumby ] Using a differential global positioning system (DGPS) with its aerial mounted in a backpack during accuracy assessment surveys of mangrove habitats. [Photograph: P. Mumby]

   

Two-man kayak set up for mangrove surveys where very shallow water prevented access by powered boats. On board are a differential global positioning system (DGPS), two PAR detectors connected to a radiometer for measuring LAI, laminated hard copy of a geometrically corrected SPOT XS image for the area and printed sheets for recording LAI. [Photograph: C. Clark] Climbing into the mangrove canopy to get a DGPS fix and place the Io detector (on the end of a 40 m waterproof cable) outside the canopy. [Photograph: P. Mumby]