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TEMPORAL AND SPATIAL DYNAMICS OF PARASITE RICHNESS IN A DAPHNIA METAPOPULATION
Author(s) -
Ebert Dieter,
Hottinger Jürgen W.,
Pajunen V. Ilmari
Publication year - 2001
Publication title -
ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.144
H-Index - 294
eISSN - 1939-9170
pISSN - 0012-9658
DOI - 10.1890/0012-9658(2001)082[3417:tasdop]2.0.co;2
Subject(s) - species richness , epibiont , ecology , metapopulation , biology , body size and species richness , population , biological dispersal , spatial heterogeneity , host (biology) , intraspecific competition , interspecific competition , crustacean , demography , sociology
Several models have been suggested to explain variation in parasite richness among populations. Most of these models are based on epidemiological factors (population size, number of host species), biological factors (patch quality, interspecific competition) and the spatial and temporal structure of the host metapopulation. We studied the parasites of 137 rock pool populations of the planktonic crustacean Daphnia magna to determine the factors that account for total parasite richness, richness of endoparasites and epibionts, and the presence/absence patterns of individual parasite species. The rock pools of 86 of these populations have been studied since 1982, and it is known how long these pools have been continuously inhabited by Daphnia. By far the best predictor of total parasite richness was host population age, which explained ∼50% of the variance. While endoparasite richness increased linearly with age over 16 yr, epibiont richness saturated ∼3 yr after pool colonization, which may be explained by the higher dispersal rate of epibionts. After we corrected for host population age, endoparasite richness was positively correlated with the water volume of the rock pool (an estimator for host population size), and epibiont richness was correlated with water conductivity. Pools with lower water conductivity (less influenced by the brackish water of the Baltic Sea) had more epibiont species. The local network size of the host metapopulation (local pool density and number of pools per island) hardly influenced parasite richness. There was also no strong indication of spatial effects (isolation by distance and island effects) on the parasite community. The factors that were correlated with species richness were, however, not the same as those related to the presence of single parasite species. At least for certain epibionts, it appears that presence/absence patterns were influenced by interspecific competition. In conclusion, our analysis shows that predictions derived from epidemiological and temporal models, but not from spatial models, can explain parasite richness patterns, despite apparent conflicting patterns found for individual parasite species. Our analysis extends the scope of these models, which were previously supported mainly with helminths, to bacteria and protozoa.