Publication Date:
2021-07-16
Description:
Amphipod crustaceans were collected from 251 spots in aquatic habitats of Fars province during July 2000 and May 2002. Different means such as aquatic nets or strainers, with strong handles and rings, were used to collect amphipods among macrophytes, leaves, roots, sands, and detritus. All collections were in daytime. To perform a systematic work, a "type‟ habitat was selected in each of the 9 station points in 7 water basins and 2 sub-basins in the province, and their populations became subjected to morphological studies. Precise drawings were made from different parts of the body (e.g. head capsule, eyes, mouth parts, antennae, pleosomes, epimeral plates, first coxal plate, key moving appendages like seventh pereopod, third uropod, and telson). These drawings were used to compare with existing identification keys. Extensive studies on each of these populations showed that they all belong to the family GAMMARIDAE, genus Gammarus and are members of the Gammarus pulex-group, an artificial group. It was impossible to identify these populations using existing keys; hence more subtle studies are needed. Regarding the so much diversity among amphipod populations in Fars, it seems that a specific identification key for this region must be produced. Some of important environmental factors were measured monthly during April 2001 and March 2002 in each of the selected stations, while others measured once in this year. These factors include some chemical factors including dissolved oxygen, pH, electrical conductivity, calcium and magnesium hardness, total hardness, chlorine, potassium and sulfate concentrations, and some physical factors including water temperature, depth, water current velocity and distance from the source, width, and discharge. Mean body lengths and wet weights of the 9 population were also measured in each of the habitats. All resulted data were analyzed using ANOVA, LSD, and Duncan statistical tests. Results showed great differences in average of temperature, electrical conductivity, dissolved oxygen, and depth. Some other factors like pH, and current velocity did not show any significant differences among these habitats. Body lengths and wet weights of the 9 population also showed clear and statistically significant differences amongst the populations. Putting together these results and morphological and morphometrical studies can help identifying the taxonomic situation of these populations. Collections showed that these animals are distributed in nearly-all, if not in all, fresh water habitats including springs, brooks, streams, and rivers in Fars province, with the exception of ponds, pools, or lakes _salty or fresh water_ and salty springs and rivers with more than 5 percent of salt (sodium chloride). Thus, these animals are distributed mainly in northern lotic habitats of the province, being extended southward to mid-south, and became sparse in eastern, western, and south fresh water warm springs and rivers. It seems that the southward dispersal of amphipods in this parts of the Province is limited primarily by salinity rather than temperature, or perhaps by a combination of the two. They also decrease in occurrence and number from west to east (away from the mountain regions). Also no populations of amphipods in southeast regions of the Kor water basin, including springs and brooks of Bamoo National Park were found, while their existence was reported from the here before. This could be due to the sever change in their habitats, probably as a result of agricultural fertilizers and toxins‟ pollution
Keywords:
Biology
;
Ecology
;
Iran
;
Fars
;
Amphipod
;
Gammarus
;
Geographical distribution
;
Freshwater
;
Ecology
;
Taxonomy
Repository Name:
AquaDocs
Type:
monograph
Format:
application/pdf
Format:
application/pdf
Format:
147
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