Spatial patterns and floristic composition of plant communities in uninhabited islets: the case of Kaboudia (Chebba, Eastern Tunisia)

The aim of this survey was to study soil and terrestrial plants in the three Kaboudia islets (eastern Tunisia). Sampling was conducted during March 2017. Texture, salinity, pH and water content of soil were also measured. A total of 180 releves of plants were conducted according to Braun-Blanquet methods. Statistical ordination methods (Agglomerative Hierarchical Clustering, Canonical Correspondence Analysis and SIMPER procedure) were used to identify plant associations. Results showed that the soil is sandy except in the north-eastern part of the large islet where the soil is sandy-loamy. High botanical diversity is found in sampling sites (44 species, 22 families). They are mainly halophytic, psammophilous or nitrophilous plants. This study allowed us to distinguish three plant associations: Halimiono portulacoidis-Suaedetum verae in a limited zone (northeast of Gattaya), Salsolo-Cakiletum maritimae in east side of sandy coasts of Gattaya and Djebel and the dominant Arthrocnemo macrostachyi-Halocnemetum cruciati in about 80% of islets. Our results show that soil composition, salinity, water content, pH, the action of the sea and seabirds influence the diversity and distribution of plant communities in these islets.

Automated summary

The study revealed that the three Kaboudia islets in eastern Tunisia have high botanical diversity, with mainly halophytic, psammophilous or nitrophilous plants. Three plant associations were identified based on the results of the survey, each located in different geographical areas. The diversity and distribution of plant communities in these islets are influenced by soil composition, salinity, water content, pH, the action of the sea and seabirds.