Original paper

Plant communities and solitary Desert Locust abundance in the Algerian Sahara, compared to other African countries

Mahdjoubi, Djillali; Guendouz-Benrima, Atika; Petit, Daniel

Phytocoenologia Band 47 Heft 2 (2017), p. 125 - 137

33 references

published: Jul 20, 2017
published online: May 15, 2017
manuscript accepted: Jan 30, 2017
manuscript revision received: Jan 26, 2017
manuscript revision requested: Apr 18, 2016
manuscript received: Mar 9, 2016

DOI: 10.1127/phyto/2017/0124

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ArtNo. ESP024004702002, Price: 29.00 €

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Abstract

Abstract 
Aims: The Desert Locust (Schistocerca gregaria) occupies vast territories in the Saharan part of Africa. Its habitats have been described separately in several localities, yet a synthetic view is lacking. Previous researchers have provided lists of plants for each study site but rarely the corresponding information about their phytosociological context. The aim of this work was to give insights into the classes and alliances hosting the Desert Locust throughout the Saharo-Sindian and Saharo-Sahelian area. Location: We investigated four regions in the center and in the southern parts of Algerian Sahara, with altitudes ranging from 300 to 1050 m a.s.l. We also considered six localities taken from literature, of which two and four were selected in the Saharo-Sindian and Saharo-Sahelian regions respectively. Methods: We sampled 466 relevés between 2007 and 2013 to record the abundance-dominance of plants, and the density of Desert Locust. Sampling dates were adjusted to insect presence. The plant assemblages were defined by Ward’s clustering method to obtain a balanced number of samples. The fidelity (phi coefficient) of plant species in the assemblages found was calculated. The link between Desert Locust density and different environmental parameters, including vegetation alliance proportions, was estimated through correlation analysis. Results: Hierarchical classification revealed 16 plant assemblages that do not clearly fit into the phytosociological system. Each assemblage contains species belonging to several alliances, highlighting the difficulty in defining plant associations in desert ecosystems. Desert Locust abundance was positively linked to the percentages of Saharo-Sindian plants and of the Antirrhino-Pithurantion scopariae alliance, but negatively so to plants associated with saline-gypsum soils. As with the Acacio-Panicion, the Antirrhino-Pithurantion scopariae is a desert steppe developed on oued edges (temporary river) but with a slightly higher annual rainfall. There is a set of stations, particularly near Bordj-Badji-Mokhtar, where the density of Desert Locust is not linked to preferred plants, suggesting that they constitute only survival biotopes. We also provide a wider view on the requirements of the Desert Locust to enter a gregarious phase, by including several literature stations of tropical Africa, in order to compare the different vegetation types. Even where the dominant vegetation remains the Acacio-Panicion, the flora is mainly Saharo-Sahelian and Sahelo-Sudanian, and not Mediterraneo-Saharo-Sindian. Conclusions: The habitat of Desert Locust is clearly defined by plant assemblages linked to the Acacio-Panicion alliance. There are significant differences between the vegetation associated with solitary and gregarious individuals. Nomenclature: For vascular plants taxa the tela-botanica database (www.tela-botanica.org/accessed 15 September 2016); for higher syntaxa of Saharan vegetation Barry et al. (1981, 1985, 1986, 1987, 1988), Kaabeche (2000), and for those relative to crops and post-cultural vegetation, Mucina et al. (2016).

Keywords

Acacio-PanicionAntirrhino-Pithurantion scopariaeDesert LocustphytosociologySaharaSchistocerca gregariavegetation