Derycke, S.; Van Vynckt, R.; Vanaverbeke, J.; Vincx, M.; Moens, T. (2007). Colonization patterns of Nematoda on decomposing algae in the estuarine environment: community assembly and genetic structure of the dominant species Pellioditis marina. Limnology and Oceanography. 52(3): 992-1001.
Derycke, S.; Van Vynckt, R.; Vanaverbeke, J.; Vincx, M.; Moens, T.
Colonization patterns of Nematoda on decomposing algae in the estuarine environment: community assembly and genetic structure of the dominant species Pellioditis marina
We performed a field experiment in the Westerschelde Estuary (The Netherlands) to characterize the
colonization dynamics of nematodes in relation to the proximity of a source population and to local
environmental conditions. The effects of colonization on the population genetic structure of the dominant species,
Pellioditis marina, were simultaneously investigated. Two contrasting sites, each containing four patches with
defaunated algae, were sampled seven times during 1 month. Site A was situated amidst Fucus stands, which
permanently harbor P. marina, while site B was approximately 100 m from any source population and
experienced more stressful environmental conditions. We hypothesized that (1) colonization in site A would
proceed faster than in site B and that (2) founder events and genetic bottlenecks would affect population genetic
structure and differentiation at site B more than at site A. We screened 992 individuals for variation in 426 base
pairs of the cytochrome oxidase c subunit 1 gene with the single-strand conformation polymorphism method. The
algal deposits at site A were indeed more rapidly colonized and reached fivefold higher densities of nematodes
than those in site B. Haplotype composition in site A was very similar to that of the source population, while rare
haplotypes were abundant and genetic diversity was lower in site B. We conclude that founder effects and genetic
bottlenecks structured the populations in site B. The genetic differences between patches in each site further
indicate that effective migration in P. marina is low and that priority effects influence the genetic structure of P.