Diversity of grasshoppers (Caelifera) recorded on the banks of a Ramsar listed temporary salt lake in Algeria

Sarah Mahloul,Daniel Petit,Abboud Harrat

doi:10.14411/eje.2016.020

Abstract

The chotts in Algeria are temporary salt lakes recognized as important wintering sites of water birds but neglected in terms of the diversity of the insects living on their banks. Around a chott in the wetland complex in the high plains near Constantine (eastern Algeria), more than half of the species of plants are annuals that dry out in summer, a situation that prompted us to sample the vegetation in spring over a period of two years. Three zones were identified based on an analysis of the vegetation and measurements of the salt content of the soils. Surveys carried out at monthly intervals over the course of a year revealed temporal and spatial variations in biodiversity and abundance of grasshoppers. The inner zone is colonized by halophilic plants and only one grasshopper species (Dericorys millierei) occurs there throughout the year. Two polyphagous species of Calliptamus, which can feed on halophilic plants migrate from adjacent areas into the inner zone in August to feed on the plants growing there. The other species of grasshoppers remain in outer zones as they are unable to feed on halophilic plants. The greatest abundance of grasshoppers from August to winter was recorded in the inner zone and in spring and early summer in the outer zones. The dependence of D. millierei on bushes of Amaranthaceae and its moderate flight ability, features of the family Dericorytidae, limit this species ability to colonize neighbouring chotts.

Highlights

Wetlands in the Mediterranean basin are rare and their estimated total surface area is 21,000 km2, of which 4,700 km2 are coastal lagoons, 2,800 km2 freshwater lakes and marshes and 11,600 km2 temporary salt lakes, the last of which occur mainly in North Africa (Britton & Crivelli, 1993).In dry parts of North Africa, sebkhas and chotts are continental depressions occupied by salty temporary lakes, which are the result of a combination of torrential rain storms and rapid runoff in quasi-desert landscapes
To understand the temporal changes in distribution we focused our studies on two species, Dericorys millierei a characteristic of the inner zone and Calliptamus barbarus, which moves from the middle zone to the inner zone at the end of summer
Our analyses show a marked difference between the inner and the two outer zones, in terms of their plant associations and grasshopper assemblages

Summary

Introduction

In dry parts of North Africa, sebkhas and chotts are continental depressions occupied by salty temporary lakes, which are the result of a combination of torrential rain storms and rapid runoff in quasi-desert landscapes. These areas are breeding and over wintering sites for birds and feeding and resting sites for numerous species of birds that annually migrate between Africa, northern Europe and Asia (Houhamdi et al, 2009). Among the North African wetlands of international importance, the chott complex on the Constantine plateau in eastern Algeria is located between the wilayas of Oum-El-

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