摘要:

SUMMARY1. The abundance of blackfly species along the length (140 km) of the multiply impounded Buffalo River, eastern Cape, South Africa, was studied between 1986 and 1988.2. Twenty‐three species of blackflies were recorded, most of which (95%) were usually found 5–10 km from the source.3. Impoundments favoured five lower‐reach (pest) blackfly species at the expense of two upper‐reach (non‐pest) species. Impoundments have therefore shifted the distribution of blackfly species ‘upstream’, and have increased the distribution of pest blackflies.4. The smallest impoundment, situated in the Upper Foothill Stony Run Zone, had the greatest effect on blackfly distribution.5. There was no typical filter‐feeding guild below impoundments. Possible reasons for this included the discharge of toxic algae from impoundments, the lack of compensatory releases, the sudden drying of impoundment tailwaters and the paucity of natural lakes in southern Africa which precludes a pre‐adapt

ISSN:0046-5070    

DOI:10.1111/j.1365-2427.1995.tb00391.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

SUMMARY1. The amphipodGammarus pulex(L.) is increasingly used in toxicity assessments and is usually obtained from wild populations. Interpopulation variability in response to toxicants may be due to genetic or phenotypic differences and could be large in wild‐caught organisms exposed to different environmental conditions. This paper describes an investigation designed to assess the extent of lethal and sublethal variability between four different G.pulexpopulations when exposed to zinc, and to determine whether differences observed in the parental generation were also apparent in offspring bred in the laboratory.2. The mortality of G.pulexfrom one of the four field‐caught populations (Crags Stream) was significantly lower than for animals from the other three populations for the first 2 days of exposure. After 6 days’ exposure the LC50values for all four populations did not differ significantly, and were approximately 1.0 mg Zn 1‐−1. Sublethal effects on feeding rate after 6 days’ exposure were also similar for all four populations (feeding rate EC50approximately 0.5 mg Zn 1‐−1).3. Lethal effects on the F1generation were similar among the four populations, in contrast to the short‐term differences observed in the parental generation. These results suggest that interpopulation differences in zinc tolerance in G.pulexare short‐lived, and phenotypically rather tha

ISSN:0046-5070    

DOI:10.1111/j.1365-2427.1995.tb00392.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

SUMMARY1. The relationships between levels of metals (Zn, Cu) in the environment (water, sediment) and in the tissues of three species of amphipod crustaceans were investigated in superficial and interstitial ecosystems of the Rivers Rhone and Ain, France.2. Epigean and hypogean amphipods differed in their ability to accumulate Zn and Cu. At all sites,Gammarus fossarum(epigean) showed lower Zn or Cu body concentrations thanNiphargusof,rhenorhodanensisorNiphargopsis casparyi(hypogean). Differences were also observed between the two interstitial taxa.3. A significant difference among sites was observed for metal concentrations in sediment. In contrast, no significant inter‐site differences were found for metal concentrations in organisms.4. No significant correlation was found between metal concentrations in the three taxa and quantities of metals in the water. A positive correlation was observed between Zn and Cu body content inGammarus fossarumand metal level in the sediment. No relationships were found between interstitial amphipods and metal concentrations in the sediment.5. Differences in accumulation rates among the three amphipod species suggest their potential use as biological indicators for monitoring metal pollutio

ISSN:0046-5070    

DOI:10.1111/j.1365-2427.1995.tb00393.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

Books review in this article:Limnology of Mountain Lakes. EditedByJ. Fott (1994)Colpodea (Ciliophora). Protozoenfauna Vol. 4/1. EditedByD. Matthes. W. Foissner(1993)Taxonomische und Okologische Revision der Ciliaten des Saprobiensystems (Band HI: Hymenostomata, Prostomatida, Nassulida). W. Foissner, H. Berger, F. Kohmann(1994)

ISSN:0046-5070    

DOI:10.1111/j.1365-2427.1995.tb00394.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

ISSN:0046-5070    

DOI:10.1111/j.1365-2427.1995.tb00395.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY