May 2019 DOI 10.14302/issn.2637-6075.jpae-19-2803
Chibueze Izah SylvesterCorresponding author
Department of Biological Sciences, Bayelsa Medical University, Yenagoa, Bayelsa State, Nigeria.
This study evaluated the phytoplankton community of Taylor creek from Polaku to Agbia between November 2013 and July 2014. Sampling was carried out in 12 locations along the stretch of the creek following standard protocol. The phytoplankton enumeration was done and identified accordingly. In all the 12 locations, 100 species of phytoplankton belonging to 14 taxonomic groups including Bacillariophyta (31 species), Chlorophyta (25 species), Pyrrophyta (4 species), Cyanophyta (17 species), Spermatophyta (9 species), Euglenophyta (3 species), Phaeophyta (1 species), Heterokontophyta (2 species), Myxophyta (1 species), Xanthophyta (1 species), Chrysophyta (2 species), Lycopodiophyta (1 species), Cryptophyta (1 species), Dinophyta (2 species). Bacillariophyta, Chlorophyta, Cyanophyta and Spermatophyta with occurrence rate of 36%, 34%, 10% and 10%, respectively were the predominant phytoplankton in the study area occurring in all the locations across the period of the study. The various species have some distinct environmental condition that enable them thrive in their niche, and this determines the structure of the phytoplankton in the study area. The diversity indices provided information about the distribution and health condition of the creek. The study showed significant relationships between Shannon-Wiener, Menhinick, Margalef, equitability and Fisher-alpha indices. The ecosystem showed moderate to heavy pollution based on Shannon Wiener index. There is the need for improved method of waste disposal and other anthropogenic activities being carried in and/ or within the creek.
Dec 2025 DOI 10.14302/issn.2768-5209.ijen-25-5762
A. Abdellatif MahaCorresponding author
Sudan's ecological landscape is characterized by various zones, including deserts, semi-deserts, and savannas, which host a diverse array of forests, rangelands, and numerous plant and animal species. However, the sustainable management of these resources is becoming increasingly challenging due to human activities and the impacts of climate change. This article presents the results of a research project focused on monitoring and documenting biodiversity in Sudan's semi-arid regions, particularly emphasizing insect diversity. Insects are vital for maintaining ecosystem health through processes such as nutrient cycling, decomposition, pollination, and acting as natural predators to pests. Field surveys were conducted across three Sudanese states—North Kordofan, Gezira, and Khartoum—to assess the diversity of flora and fauna. Specifically, El Rawakeeb semi-arid land in Khartoum state was investigated, which comprised three sites with varying soil elevations: a hilly site at 420 meters above sea level, a flat site at 416 meters, and a valley site at 411 meters. Researchers utilized direct collection methods and butterfly nets to gather insect specimens, which were subsequently preserved and identified for further analysis. Diversity indices, including Simpson’s Diversity Index, Shannon-Wiener Index, and Margalef Richness Index, were computed to compare the biodiversity of these sites, along with metrics for evenness and species richness. Permanova analysis was carried out for insect variation between the study sites. A total of 1541 insect specimens were gathered from El Rawakeeb, encompassing 34 species distributed across 21 families and 9 orders. The order Lepidoptera exhibited the greatest number of species (35.29%), followed by Coleoptera (20.59%). The orders Neuroptera, Orthoptera and Thysanoptera recorded the fewest species (2.94% each). From the hilly site, 514 insect specimens were collected, representing 9 orders, among which Hymenoptera included 4 species, while Lepidoptera had 3 species, and Odonata, Orthoptera, and Thysanoptera each had 1 species. The highest individual counts were recorded for Copriniklobe (dung beetle), Dacus longistylus (fruit fly), Camponotussp. (carpenter ant), and Anax ephippiger (dragonfly). In a flat site, 484 insect specimens were collected, classified into 15 species, 12 families, and 7 orders. The highest individual counts were noted in four species: Onthophagusnuba (dung beetle), Dacus longistylus (fruit fly), Camponotussp. (carpenter ant), and Anax ephippiger (dragonfly). In a valley site, 543 insect specimens were collected, categorized into 17 species, 16 families, and 9 orders. Insect Diversity in three research sites. Simpson's Diversity Index revealed varying levels of insect diversity across the three sites. The valley site exhibited the highest diversity level with an index score of 0.857, followed by the flat site at 0.826, and the hilly site at 0.819. The Shannon diversity index of 2.22 indicated the highest diversity among the three sites, suggesting a relatively diverse insect community. The relative abundance of insects was greatest in the valley site at 35.24%, followed by the hilly site at 33.35%, and the flat site at 31.41%. The Margalef Richness Index indicated a moderate level of richness in the insects collected from the three locations. Certain insect species were found in some sites but were absent in others. The PERMANOVA revealed notable variations among the three study sites (F = 2.24, p-value = 0.035).