Works concerning zooplankton of freshwaters of the western area of Algeria are only very fragmentary and remain at an embryonic state. Remediating to this situation, it led a study of the biodiversity and zooplanktoni...Works concerning zooplankton of freshwaters of the western area of Algeria are only very fragmentary and remain at an embryonic state. Remediating to this situation, it led a study of the biodiversity and zooplanktonic populations distribution in time and space in the Boughrara dam lake which remains subject to a strong pollution coming essentially from Morocco. The preliminary results of the faunistic analysis of the zooplanktonic populations enabled to highlight an important richness of zoological groups. The CFA （correspondences factorial analysis） and the AHC （ascending hierarchical classification） methods used both enabled to define the species distribution of both open waters and littoral ones, and also to perform existing affinities between them and the state of the used medium. Compared to other barrages, such as those of Bouhanifia and of Sarno, the zooplanktonic populations of both open waters and littoral populations appear to a great extent numerous in rain period. On the quantitative and qualitative level, the zooplanktonic populations strongly suffer from the pollution contamination coming from the Mouillah River especially in summer period. It is time to think about the protection of this fauna which is the second trophic chain link and this intending to preserve the ecosystems in an equilibrium state and to consider the exploitation of natural resources in the realization of an aquacultural farm.展开更多
With the aim of assessing the benthic macroinvertebrates’ diversity, a study was carried out in some tropical forest streams of the Nyong River catchment in Cameroon from February 2019 to February 2020. A total of 16...With the aim of assessing the benthic macroinvertebrates’ diversity, a study was carried out in some tropical forest streams of the Nyong River catchment in Cameroon from February 2019 to February 2020. A total of 167 samples were carried out from 13 stations during 13 months. Some environmental variables were measured. These parameters varied more or less from station to station but significantly at the temporal level. In this study, 13,690 benthic macroinvertebrates belonging to 4 phyla, 7 classes, 16 orders and 93 families were collected. The benthic macroinvertebrates were more abundant and more diversified in the stations whose waters are well oxygenated and present a moderate current compared to the stations with a very weak current. The diversity varied significantly from 1.33 ± 0.14 bits/ind to 2.00 ± 0.35 bits/ind and the high values were found in stations with multiple substrates and well-oxygenated waters. Temporally, the diversity varied significantly from 1.10 ± 0.16 bits/ind in NM sampling station in February 2020 to 1.87 ± 0.1 bits/ind in the OB sampling station in September. In addition, the settlement was more abundant during the short dry season, more precisely during the month of August (1471 individuals) but richer during the long dry season during the month of February (54 families). The distribution of the abundances of the benthic fauna in the different stations made it possible to identify five typological groups using the rarefaction curves, the ascending hierarchical classification and the principal component analyses. Each of these five groups is characterized by a specific taxonomic richness, composition and abundance.展开更多
The first synopsis of Mesozoic weevils （Curculionoidea： Coleoptera） is pre- sented. Changes of family, genera and species abundance during the Mesozoic revealed three distributional patterns. The Jurassic （Karatau...The first synopsis of Mesozoic weevils （Curculionoidea： Coleoptera） is pre- sented. Changes of family, genera and species abundance during the Mesozoic revealed three distributional patterns. The Jurassic （Karatau） fauna was dominated by the Nemony- chidae. During the Early Cretaceous （beginning at the Jurassic/Cretaceous border）, the Ithyceridae was the prevalent group with a significant role played by the Nemonychidae. In the Late Cretaceous （Cenomanian and Turonian）, the major groups were the Curculion- idae and Brentidae. Obviously, the change of weevil fauna during this period was due to the expansion of the angiosperms, which provided multiple niches in their vegetative and reproductive organs for weevil development.展开更多
文摘Works concerning zooplankton of freshwaters of the western area of Algeria are only very fragmentary and remain at an embryonic state. Remediating to this situation, it led a study of the biodiversity and zooplanktonic populations distribution in time and space in the Boughrara dam lake which remains subject to a strong pollution coming essentially from Morocco. The preliminary results of the faunistic analysis of the zooplanktonic populations enabled to highlight an important richness of zoological groups. The CFA （correspondences factorial analysis） and the AHC （ascending hierarchical classification） methods used both enabled to define the species distribution of both open waters and littoral ones, and also to perform existing affinities between them and the state of the used medium. Compared to other barrages, such as those of Bouhanifia and of Sarno, the zooplanktonic populations of both open waters and littoral populations appear to a great extent numerous in rain period. On the quantitative and qualitative level, the zooplanktonic populations strongly suffer from the pollution contamination coming from the Mouillah River especially in summer period. It is time to think about the protection of this fauna which is the second trophic chain link and this intending to preserve the ecosystems in an equilibrium state and to consider the exploitation of natural resources in the realization of an aquacultural farm.
文摘With the aim of assessing the benthic macroinvertebrates’ diversity, a study was carried out in some tropical forest streams of the Nyong River catchment in Cameroon from February 2019 to February 2020. A total of 167 samples were carried out from 13 stations during 13 months. Some environmental variables were measured. These parameters varied more or less from station to station but significantly at the temporal level. In this study, 13,690 benthic macroinvertebrates belonging to 4 phyla, 7 classes, 16 orders and 93 families were collected. The benthic macroinvertebrates were more abundant and more diversified in the stations whose waters are well oxygenated and present a moderate current compared to the stations with a very weak current. The diversity varied significantly from 1.33 ± 0.14 bits/ind to 2.00 ± 0.35 bits/ind and the high values were found in stations with multiple substrates and well-oxygenated waters. Temporally, the diversity varied significantly from 1.10 ± 0.16 bits/ind in NM sampling station in February 2020 to 1.87 ± 0.1 bits/ind in the OB sampling station in September. In addition, the settlement was more abundant during the short dry season, more precisely during the month of August (1471 individuals) but richer during the long dry season during the month of February (54 families). The distribution of the abundances of the benthic fauna in the different stations made it possible to identify five typological groups using the rarefaction curves, the ascending hierarchical classification and the principal component analyses. Each of these five groups is characterized by a specific taxonomic richness, composition and abundance.
文摘The first synopsis of Mesozoic weevils （Curculionoidea： Coleoptera） is pre- sented. Changes of family, genera and species abundance during the Mesozoic revealed three distributional patterns. The Jurassic （Karatau） fauna was dominated by the Nemony- chidae. During the Early Cretaceous （beginning at the Jurassic/Cretaceous border）, the Ithyceridae was the prevalent group with a significant role played by the Nemonychidae. In the Late Cretaceous （Cenomanian and Turonian）, the major groups were the Curculion- idae and Brentidae. Obviously, the change of weevil fauna during this period was due to the expansion of the angiosperms, which provided multiple niches in their vegetative and reproductive organs for weevil development.
