Jansen, E.J. (2008) Using remote sensing to predict macrobenthos abundance in the Banc d'Arguin, Mauritania. Master's Thesis / Essay, Biology.
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Abstract
The tidal zone of the Banc d'Arguin, Mauritania is famous for its large number of birds, in particular wintering waders. The ecosystem is characterized by diverse tidal flats ranging from bare, dry and sandy flats to very silt and moist seagrass covered mudflats. These physical and biological differences have great influence on the local macrobenthic communities, which in their turn affect the density of foraging birds. The goal of this research is to investigate the relations between remotely sensed variables and parameters such as seagrass cover and moist content and to link those with macrobenthos occurrence and abundance. We took 111 samples on 56 different stations over the extent of the whole ecosystem. On each station we quantified seagrass cover, moist content, penetrability and detritus content. From each sample we determined the species composition and estimated the Ash-Free Dry Mass (AFDM). 4289 benthic specimens were found on a total surface area of 2.014 m2. The average AFDM of the total macrobenthos found was 28.6 g per m2. 70 Different species were identified, with bivalves being most abundant in numbers (1535 per m2), and Mass (25.2 g AFDM per m2). The large bloody cockle Anadara senhlis accounted for 20.3 g AFDM per m2. Polychaetes and gastropods were most diverse in terms of species numbers: in both taxa 19 species groups were identified. Different layers of Landsat7 satellite images were used to calculate NDVI and proxies for inundation time and temperature. Groundtruthing was performed by comparing this remotely sensed data to the groundparameters collected in the field. Most significant positive correlations were found between NDVI and seagrass and between temperature and moist content. The total AFDM of bivalves was positively correlated with seagrass and temperature derived from satellite images. Detritus content of the sediment was positively correlated with gastropod abundance. Regression analyses show that for some species, in particular L. lacteus large amount of the variation in the abundance can be accounted for by the remotely sensed data (McFadden R2 = 0.74). Based on these statistical models and the bands from the satellite image covering the whole area it was possible to accurately predict the abundance of L. lacteus in each location. L. lacteus makes up 69 percent of the total amount of harvestable food in the Banc d'Arguin for the red knot. Hence, a red knot (C. canutus) resource map could confidently be constructed.
| Item Type: | Thesis (Master's Thesis / Essay) |
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| Degree programme: | Biology |
| Thesis type: | Master's Thesis / Essay |
| Language: | English |
| Date Deposited: | 15 Feb 2018 07:31 |
| Last Modified: | 15 Feb 2018 07:31 |
| URI: | https://fse.studenttheses.ub.rug.nl/id/eprint/9105 |
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