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C. Amoros  C. Jacquet 《Hydrobiologia》1987,145(1):333-341
Methodological investigations, using remains of Bosminidae and Chydoridae, were undertaken to study the development of ecosystems in former river channels. Four biotopes from two former channels of different ages were used in this work. The Copepoda and Cladocera populations characterized each of the 11 sampling stations in relation to ecological factors, which are linked to the development stage in each ecosystem. Analysis of only the Bosminidae and Chydoridae populations presented practically the same information as an analysis of the total populations of Copepoda and Cladocera. The distribution of Bosminidae and Chydoridae remains taken from the surficial sediments at the deepest point of each former channel strongly resembled the distribution of the living populations sampled at several stations during one full year. Therefore, Bosminidae and Chydoridae remains could provide us with pertinent information concerning each phase of ecological succession that occurs in abandoned river channels.  相似文献   
3.
Tremel  Birgitta  Frey  S.E.  Yan  Norman D.  Somers  Keith M.  Pawson  Trevor W. 《Hydrobiologia》2000,432(1-3):195-205
This study identified two scales of pattern in the assemblages of Chydoridae (Crustacea, Branchiopoda, Anomopoda) in the shallow (<2 m) littoral zone of Plastic Lake, Ontario, Canada in the autumn of 1987. Twenty chydorid species were collected in 15 over-night sets of funnel traps in each of four habitat types. Analysis of variance multivariate analysis of variance, and discriminant function analysis revealed that assemblages differed among the habitats. Alona intermedia, Alona quadrangularis and Chydorus bicornutus were particularly abundant in the most structurally diverse habitat type – muddy, rock-strewn areas with approximately 40% bottom cover by the pipewort, Eriocaulon septangulare. In contrast, Anchistropus cf. minor was caught most often on bare shelves of rock. A second set of analyses demonstrated that chydorid assemblages also differed at a smaller scale, i.e. with local patchiness in bottom cover by the dominant macrophyte (E. septangulare). The abundance of Alona affinis was positively correlated with cover by E. septangulare, whereas Anchistropus cf. minor was caught mainly in microhabitats without vegetation. Alona intermedia and A. quadrangularis were most abundant in microhabitats with intermediate amounts of vegetation, suggesting their abundance is influenced by habitat factors other than vegetation.  相似文献   
4.
A morphological comparison of specimens previously assigned to Alona eximia Kiser, 1948 from tropical Africa, Eastern Asia and the Americas shows that this species-group shares a number of morphological characters on the postabdomen, head pores, first antenna and second and fourth limb that separate them from Alona Baird, 1843 but unite them with Nicsmirnovius Chiambeng & Dumont, 1999. Alonella fitzpatricki Chien, 1970, formerly believed to be a junior synonym of A. eximia, is separated from the latter and assigned to the genus Nicsmirnovius. Two new taxa, from Africa and the Island of Socotra (Yemen) are added to the genus. The relationship between the specialised habitat of these chydorids and their morphology is discussed. The geographic range of all known populations is figured and a key to species is presented.  相似文献   
5.
Aim We provide the first in‐depth study of the Branchiopoda of the rain forests of Cameroon and also of the African continent. Location Surface water environments, Cameroon. Methods Qualitative plankton samples were collected in all types of surface water environments present, ranging from big lakes to water collected in rock crevices or fallen fruit cavities. A tow or hand‐held plankton net of mesh size 100 μm was used, and water volumes filtered were at least several m3 in large water bodies, or half to whole water volume in small water bodies. Results We recorded 61 species (53 first records for the country), based on 700+ samples collected between September 1998 and March 2002. Anomopoda (92%) was the dominant order, followed by Ctenopoda (6.5%) and Cyclestherida (1.5%). Chydoridae (67%) was the most speciose family followed by Macrothricidae (6.5%) and Daphniidae (5%). Alona (11%) was the dominant genus followed by Chydorus (10%) and Pleuroxus (8%). Several species of Chydorinae, especially of the genus Pleuroxus, are shared with continental Eurasia–North America, but are absent from the Mediterranean and desert–steppe–savanna zones of Africa (boreal–tropical disjunction). Daphnia was absent, as in most tropical lowlands. No single species was really abundant, and a majority were rare to very rare, and of restricted occurrence within the rain forest patches. Comparing Africa, South America and Southeast Asia, we found a current total of 196 species for the combined rain forest areas, out of a world total of 500+ species. Systematic trends in richness at three taxonomic levels were the same for all continents: Anomopoda–Ctenopoda–Cyclestherida at ordinal level, Chydoridae–Daphniidae–Macrothricidae–Sididae at family level and Alona–Chydorus–Macrothrix–Diaphanosoma at genus level. Southeast Asia was richest (111 species, 14 endemics) with South America a close second (110 species, 27 endemics). Africa was the most species‐poor (95 species, of which only 5 are endemics). Main conclusions We hypothesize that the post‐Miocene cooling and aridization of the world climate hit the freshwater biota of Africa particularly hard, with more extinction here than elsewhere, and little recolonization. Most extinction occurred in the savanna‐desert belt, and eight disjunct boreal species (four Pleuroxus, Picripleuroxus laevis, Kurzia latissima, Alonella exigua, and Monospilus dispar) survive morphologically unchanged since pre‐Pleistocene times in the Cameroon rain forest. Slow evolution thus appears typical of these cyclic parthenogenetic branchiopods in which sexual recombination occurs only at intervals. Illustrative of the same slow evolution is the fact that the two endemic cladocerans of Cameroon (Nicsmirnovius camerounensis and Bryospilus africanus) belong to tropicopolitan genera of Gondwanan age.  相似文献   
6.
The chydorid species Chydorus reticulatus Daday, 1898 and Chydorus ventricosus Daday, 1898 are redescribed and literature records reevaluated on the basis of new material from India.Contribution 9 Department of Biology, Indiana University, Bloomington. This study was supported in part by NSF Grant DEB76-20237 to D. G. Frey.  相似文献   
7.
Yu. I. Sorokin 《Hydrobiologia》1992,242(2):105-114
Exchange of phosphate between components of the reef bottom and the water column were studied on reefs around Heron Island (Great Barrier Reef), both in aquaria and in in situ enclosures, using radioactive phosphorus (32P) as a tracer. Living corals, dead corals, coral rubble overgrown with periphyton, and soft sediments of coral sand were used in experiments. In all of these components of bottom reef biotopes, two opposite flows of inorganic phosphate were recorded and measured, i.e. the rate of PO4-P uptake from water (Ac), and its release (Ae). At ambient PO4-P concentrations in water of 0.1– 0.3 µmoll–1, both flows varied in living corals and coral rubble between 10 and 70 µg P kg–1 h–1, 3–10 mg P m–2 day–1, and in coral sand between 10 and 30 µg P kg–1 h–1, or 2–7 mg P m–2 day–1. Under the latter concentration range (which is typical for coral reef areas), the reciprocal PO4-P flows almost balanced each other, so that net uptake (At) was very low. Often it approached zero or was positive, showing that a net PO4-P release had taken place. The uptake flow (Ac) in living coral was much more dependent on the PO4-P content in overlying water than was the release flow (Ae). The influence of conditions of illumination upon the values of Ac and Ae was comparatively low. The data obtained are used to discuss problems of phosphorus balance and dynamics in coral reef ecosystems.  相似文献   
8.
The distribution of chydorid Cladocera in Canada   总被引:3,自引:3,他引:0  
R. Chengalath 《Hydrobiologia》1987,145(1):151-157
The distribution of chydorid Cladocera in Canada is given based on the examination of 584 samples collected from all the provinces and territories from 1978 through to 1984. Some species show regional distributions, while others are widely distributed. The preferences shown by some species to particular substrates are discussed. Further evidence is presented to show that some taxa previously claimed to be conspecific in Europe and North America may be different. In some instances the adult males tend to be more highly differentiated than the females, particularly in the structure of the postabdomen. The importance of taxonomic and distributional studies in understanding the biogeography of North American chydorids is discussed.  相似文献   
9.
Paleolimnological study of plant and animal microfossils is based on either relative abundances or net accumulation rates of various taxa. Interpretation of the latter is difficult because ecological factors that influence accumulation rates have been unknown. I use a novel method of 210Pb assay to estimate net accumulation rates of bosminids and chydorids at the sediment-water interface of 15 Florida (U.S.A.) lakes which represent a wide range of trophic state, water chemistry, and morphometry. Thirty-two species of Chydoridae, and two genera of Bosminidae were recovered from the lake sediments. Accumulation rates of 6 of the 11 more abundant chydorid species and both bosminid taxa were positively correlated with trophic state as measured by chlorophyll a concentration. Lake size was positively correlated with accumulation rates of 4 chydorid species and both bosminids. Weedbed area was positively correlated with accumulation rates of 2 chydorids, but neither bosminid. Lakewater pH was positively correlated with only one chydorid species accumulation rate. Multiple regression models explain statistically nearly all of the variance in each of the limnological variables, and can be used as transfer functions for paleolimnological inference.  相似文献   
10.
Morphological study of Alona protzi Hartwig, 1900, Alona phreatica Dumont, 1983 and Alona smirnovi Petkovski &; Flößner, 1972 reveals close affinities with Alona labrosa Vasiljeva &; Smirnov, 1969. We separate these four species from the polyphyletic Alona Baird, 1843 (Anomopoda: Chydoridae). United under Phreatalona gen. nov., these taxa share primitive features on the limbs, together with specializations to a rheic life mode. Phreatalona contains some of the only true hyporheic taxa within the Cladocera. Endemism in two ancient lakes (P. smirnovi and P. labrosa) and a preference for river sediments in Europe (P. phreatica and P. protzi) suggest a long isolation from typical littoral/benthic biotopes. We discuss close links with southern vicariant Nicsmirnovius, the position of these (hypo)rheic chydorids within the subfamily and their affinities with Acroperus. We remark an independent evolution of external (habitus, postabdomen) vs. internal (limb) morphology in the protzi-complex. Phreatalona is likely tertiary in origin, evolving from a littoral alonine adapting to rheic and finally hyporheic environments. Baikal endemic P. labrosa is likely the most primitive species of the genus. We discuss adaptations and evolution in the hyporheic and the effect on dispersal and biogeography of Phreatalona.  相似文献   
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