|Tolerance differences and interspecific competition in three members of the amphipod genus Gammarus|
Dennert, H.G. (1974). Tolerance differences and interspecific competition in three members of the amphipod genus Gammarus. Hydrobiol. Bull. 8(1-2): 109
In: Hydrobiological Bulletin. Netherlands Hydrobiological Society: Amsterdam. ISSN 0165-1404, more
|Also published as |
- Dennert, H.G. (1974). Tolerance differences and interspecific competition in three members of the amphipod genus Gammarus, in: Proceedings of the International Symposium on Ecology and Physiology of the Brackish Environment, Amsterdam, September 4-7, 1973. Hydrobiological Bulletin, 8(1-2): pp. 109, more
Gammarus Fabricius, 1775 [WoRMS]; Marine; Brackish water
1) In a series of experiments with G. pulex, G. duebeni celticus and G.d. duebeni populations, pure or mixed, their tolerances for several temperature/salinity conditions have been determined. Tested were 100%, 10%, 1% and 0.1% seawater in combination with temps of 5, 10 or 15°C. In general all species tolerated the 5° C conditions better than those with higher temperatures, and the middle salinity range (1% for G. pulex, 1% and 10% for G.d. celticus and G.d. duebeni) better than the lower or higher salinities. (2) In nearly all situations tested G. pulex had a lower survival rate than G.d. celticus and G.d. duebeni. (3) Notwithstanding the sometimes unfavourable conditions for G. pulex, this species can compete successfully with G.d. celticus under most of the experimental conditions, but the interspecific relations between G. pulex and G.d. duebeni end in the competitive exclusion of the species. These results support 2 theories: (1) G. pulex is able to compete successfully with G.d. celticus and to expel the latter of its niche, and (2) G.d. duebeni is capable to invade freshwater and to establish inland populations. (4) The differences demonstrated between G.d. celticus and G.d. duebeni are an argument for a different development and different capabilities of both subspecies. (5) Sterile interspecific matings between these (sub) species are temperature dependent and do not play a major role in the interspecific relations connected with competition.