Alain Thiéry

Multispecies coexistence of branchiopods (Anostraca, Notostraca & Spinicaudata) in temporary ponds of Chaouia plain (western Morocco): sympatry or syntopy between usually allopatric species

The study of the structure of communities of Crustacean branchiopods Anostraca, Notostraca and Spinicaudata of temporary ponds in Morocco revealed the existence of a geographical area with a particularly diversified number of species. Over a few hectares, 11 species, among the 18 known in Morocco, are present. While most of them are usually allopatric and belong to distinct associations, indicative of particular ecological and climatic conditions, they can coexist in Chaouia plain, either in adjoining ponds (sympatric species) or in the same pond (syntopic species). In one pond we could find up to 10 phyllopods: 6 Anostraca, 2 Notostraca and 2 Spinicaudata.This faunistic diversity may result from abiotic features (the location of the ponds at the boundary of two climatic areas) and from a heterogeneous geological substratum, creating a patchwork of temporary ponds with various mesologic conditions.Secondarily, this diversity may result from different life history characteristics of each coexisting species. As all species hatch synchronically, coexistence is only possible if their growth rates and life span are different. This implies that horizontal and vertical distribution, and exploitation of food supplies in the habitat differ for each ecophase of the syntopic species (spatial and trophic exclusion).

The geographic distribution of the European Branchiopods (Anostraca, Notostraca, Spinicaudata, Laevicaudata)

The ‘Large Branchiopod’ fauna of Europe consists of 72 species and sub-species: 50 anostracans, 8 notostracans, 12 spinicaudatans, and 2 laevicaudatans. Their geographical distribution is mapped, and remarks on ecological requirements of species are given.

Odonata, Amphibia and Environmental Characteristics in Motorway Stormwater Retention Ponds (Southern France)

Water and its protection against pollution is an urgent priority for all countries around the world. In that context, France, through its Water Law in 1992 obliged the motorway companies to build stormwater retention ponds along roads in order to protect the water resource from transport pollution and to control water flow during rainstorms. We propose to evaluate how much these ponds can be attractive for aquatic species and then evaluate their role in regional biodiversity. Six retention ponds, localized in the Mediterranean region, were investigated during one year (March 2002–March 2003) for their chemical and biological characteristics such as bottom type, trace metal composition, water quality and phytocenose composition. These variables were recorded and correlated with species richness of amphibian and dragonfly communities. Stormwater retention ponds showed a high concentration of copper and zinc in top sediment layer and herbicides in water column. Dragonfly richness was higher in ponds with a natural bottom than ones with an artificial bottom (PEHD membrane) while amphibian richness was more sensitive to the structure of the surrounding landscape. These habitats appeared to be very attractive for Odonata species and tend to favorize uncommon species present in the survey region such as Ischnura pumilio and Erythromma viridulum. Amphibian were found to be representative of anthropophilous guild.

Resting eggs of Anostraca, Notostraca and Spinicaudata (Crustacea, Branchiopoda) occurring in France: identification and taxonomical value

The external egg morphology of the phyllopod species recorded in France is described by means of S.E.M. Differences in diameter and ornamentation of envelope are stressed. We propose a dichotomous key to allow the identification of species even when their biotope is dry. Results are compared with previous studies on Anostraca, Notostraca and Spinicaudata and their taxonomical value is discussed.

Crustacean assemblage and environmental characteristics of a man-made solar saltwork in southern France, with emphasis on anostracan (Branchiopoda) population dynamics

Physical and chemical variables, anostracan populations (Artemia parthenogenetica and Branchinella spinosa) and other biota were studied during 1996–1997 in a Camargue saltern (max. depth ∼1 m). The taxonomic composition and density of macroinvertebrates were investigated twice monthly, based on benthic substrate and water column samples. Fauna was composed of three groups in terms of numerical importance. The benthic macroinvertebrates were represented only by nematodes (< 50 ind. m−2 to > 500 ind. m−2 in November–December and May respectively). The zooplankton was dominated by crustaceans, one cladoceran, Moina salina (ranging from 670 to 2350 ind. m−2 in spring), two anostracans, Artemia parthenogenetica (< 50 ind. m−2 in autumn), and Branchinella spinosa (max. 190 ind. m−2 in December to absent in April), and two copepods, Cletocamptus retrogressus (max. density 2000 ind. m−2 in November), and Eurytemora velox (max. density 650 ind. m−2 in February–March). Insects (Chironomidae, Culicidae) were rare, with mean densities < 1 ind. m−2. The phenology of each crustacean population is discussed in relation to physical and chemical water variables. Salinity appeared to be of greatest importance regulating the population abundance.

Horizontal distribution and abundance of cysts of several large branchiopods in temporary pool and ditch sediments

Cysts of three species of anostracans (Branchipus schaefferi, Chirocephalus diaphanus,and Tanymastigites perrieri), two species of Notostracans (Triops numidicus and Lepidurus apus) and one species of Spinicaudata (Leptestheria mayeti) were collected from the upper 2 cm of dry sediments at intervals along transects from a temporary pool in an arid zone of Morocco and from two ditches in France. The horizontal distribution of viable cysts was patchy and is discussed in relation to several ecological parameters prevailing during the aquatic phase. These include vegetation distribution, depth and morphometry of the pond, dominant wind pattern, and granularity of the sediments.

OCCURRENCE OF TETRAHEDRAL EGGS IN THE STREPTOCEPHALIDAE DADAY (BRANCHIOPODA: ANOSTRACA) WITH DESCRIPTIONS OF A NEW SUBGENUS, PARASTREPTOCEPHALUS, AND A NEW SPECIES, STREPTOCEPHALUS ( PARASTREPTOCEPHALUS ) ZULUENSIS BRENDONCK AND HAMER

ABSTRACT Streptocephalus (Parastreptocephalus), new subgenus, comprises *Streptocephalus (Parastreptocephalus) sudanicus, S. (P.) lamellifer. S. (P.) kaokoensis, and S. (P.) zuluensis, new species, Brendonck and Hamer. These species all produce tetrahedral eggs, a unique feature within the family Streptocephalidae, and share a similar male antennal morphology, which differs from that in all other streptocephalids. The designated type species, S. (P.) sudanicus, is extensively redescribed. In addition, the differentiating characters for S. (P.) zuluensis are presented. Both species can be distinguished using features of the morphology of their resting eggs and of the male antennae. A key to the species is also provided. Egg morphology and male antennal morphology appear to be consistent taxonomic criteria for the proposed subgenus. The presence of taxon-related differences in egg morphology raises the question whether or not differently shaped eggs confer any selective advantage. We suggest that selective pressure on the amount of energy allocated to reproduction has resulted in the fact that eggs share a combination of characteristics (hatching response, dispersal ability, drought, and mechanical resistance), which allows them to endure a specific set of environmental conditions.

LONG-TERM DYNAMICS OF A MEDITERRANEAN ALKALINE VERNAL POOL (RHONE DELTA, SOUTHERN FRANCE)

Mediterranean vernal pools are threatened habitats that support a number of endangered/ rare plant and invertebrate species. Conservation management of these important habitats is limited by a lack of knowledge, especially concerning their past and present ecological dynamics. A multidisciplinary palaeoecological investigation was conducted on one of the last alkaline vernal pools of the Rhone delta (southern France). Results highlighted the value of a multidisciplinary approach based on several complementary methods, and provide direction for subsequent palaeoecological studies in temporary wetlands. Despite some degradation, fossil assemblages provide an accurate reconstruction of the past ecological dynamics of the vernal pool studied. The pool originated c. 1100 years ago from the infilling of an abandoned palaeochannel and its subsequent fragmentation. It may thus be considered as a legacy of past natural fluvial activity, which ended with the complete channelization and confinement of the River Rhone in 1869 AD. With natural processes disrupted, new pools may need to be artificially constructed in order to preserve the biological communities of alkaline vernal pools of the Rhone delta.

Molecular characterization of the invasive Asian tiger mosquito, Aedes (Stegomyia) albopictus (Diptera: Culicidae) in Corsica.

The Asian tiger mosquito Aedes albopictus, vector of various human viruses and parasites, has recently spread and established in many temperate regions including European countries. In the present study, we developed a simple PCR-based assay (the amplification of the internal transcribed spacer ITS2 within nuclear ribosomal rDNA) for molecular identification of A. albopictus and confirmed its presence in Corsica island. This assay may (i) facilitate future large scale studies and avoid misidentifications, especially because of the presence of co-occurring close species in this island and (ii) contribute to the monitoring of A. albopictus populations required for targeted control programs.

Epizootic algae and Protozoa on fresh water branchiopods (Anostraca, Notostraca and Spinicaudata) in Moroccan temporary ponds

Epizootic algae and Protozoa occur on the exoskeleton of fresh water branchiopods in temporary ponds in Morocco. Algal colonization seemed linked with turbid waters and access by the epibionts to the nutritive and oxygenated flows created by the rhythmical beat of the thoracic legs of the branchiopods. It also seemed linked to the mode of life (planktonic or benthic) of the host, and to their exposition to light. Appendages of anostracans, which swim ventral side up, bear a rich community of Chlorophytes, while in conchostracans, where body and appendages are protected by a bivalve carapace, and which swim ventral side down, epibionts colonize the valves, particularly near the hinge and umbo. The lack of algae on notostracans may result from their habit of living in the deeper part of ponds. Protozoans fixed on notostracan shields and on conchostracan valves or appendages, seem to benefit principally from the flow of nutrient- and oxygen-rich water created by the host.