Adema, E. (1997) Kunnen pionierssoorten in natte duinvalleien primaire successie vertragen? Master's Thesis / Essay, Biology.
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Abstract
To study the mechanism of primary succession in dune slacks we developed a relatively simple model and tested this model with an experiment in mesocosms. We assumed that the fraction of nitrogen lost by leaching will decrease with an increasing organic matter content and that species capable of Radial Oxygen Loss (ROL) can delay succession by stimulating the degradation of organic matter. Our model simulates the succession in wet calcareous dune slacks and describes the fluxes of nutrients between soil, plant and organic matter. The model revealed that Schoenus nigricans, capable of ROL, can delay succession towards Calamagrostis epigejos dominated stands. The experiment consisted of a factorial block design with four species and four treatments. The four dune slack species included two species from early successional stages (Schoenus nigricans and Samolus valerandi), capable of ROL and two species from a later successional stage (Calamagrostis epigejos and Carex nigra). The four treatments were bare soil, only plants, only organic matter and finally both plants and organic matter. The plants grew in mesocosms with a constant flow of artificial ground water. During the experiment we measured nitrate and ammonium (using an auto analyser), and oxygen, redox potential and sulphide (using needle electrodes). Furthermore we counted sulphate reducing and colourless sulphur bacteria (most probable number) at the end of the experiment in the Calarnagrostis epigejos treatments. The experiments started in July and ended in beginning of October. An equilibrium state was not reached within this period. It is, therefore, not possible to estimate adequately the fraction of leached nitrogen predicted by the model, And for that reason our hypotheses could not be tested. An experiment of several years in larger mesocosm will be needed to reach an equilibrium state. Nevertheless the used experimental design is very useful to investigate more concrete processes such as the effects of microbial mats on plant growth in early succession. From the bacterial counts and the fact that much nitrogen is lost, probably due to denitrification, it seems that micro-organisms play an important role in early succession of wet dune slacks.
| Item Type: | Thesis (Master's Thesis / Essay) |
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| Degree programme: | Biology |
| Thesis type: | Master's Thesis / Essay |
| Language: | Dutch |
| Date Deposited: | 15 Feb 2018 07:48 |
| Last Modified: | 15 Feb 2018 07:48 |
| URI: | https://fse.studenttheses.ub.rug.nl/id/eprint/10131 |
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