Aarhus Universitets segl

No. 658: Coastal dunes in Denmark - vegetation and soil chemistry

Damgaard, C., Nygaard, B. & Nielsen, K.E. 2008: Danske kystklitter – vegetation og jordbundskemi. Analyse af NOVANA-data 2004-2006. Danmarks Miljøundersøgelser, Aarhus Universitet, 66 P. – Faglig rapport fra DMU nr. 658.

 

Summary

After collecting data for three years in the Danish NOVANA monitoring program of terrestrial habitats is it now possible to give an outline of the types of analyses and models that will qualify our knowledge on the state and expected development of different natural habitats. The presented methods are expected to be further developed in the coming years.

 

In order to be specific, we have focused on the coastal dune systems, where we show that a floristic classification model with appropriate accuracy can partition fixed coastal dunes with herbaceous vegetation (2130), decalcified fixed dunes with Empetrum nigrum (2140) and humid dune slacks (2190), on the basis of plant cover data. However, it was not possible to partition coastal dunes with Juniperus spp. (2250) from the other dune systems on the species composition alone. The analyses further showed that it is not possible to select species that can serve as indicators of specific dune habitats, since these have a relative large common species pool. Field keys to characterize the different dune habitats must necessarily be hybrid keys where geomorphology and vegetation structure are important features together with species lists.

 

Analysis on the dependencies between the different types of dune vegetation and measured soil chemistry variables displayed a significant interaction between the abiotic and biotic factors of dune ecosystems. Furthermore, it was evident that it is necessary to measure and analyse both abiotic and biotic factors in the pursuit to understand the dynamics in the investigated dune habitats. However, important factors, such as accessibility to water, may be investigated in more details, since it is necessary to include all of the most important ecological factors in order to produce credible prognostic models of the development of dune ecosystems.

 

A time-series analysis of the measured indicators was briefly presented and exemplified by a preliminary calculation of the observed change in pH i coastal dunes.

 

Generally, the report has strengthened the scientific background knowledge, which is necessary to set or validate criteria for favourable conservation status for the different habitat types.

 

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