The dynamics of intestinal helminth communities in eels Anguilla anguilla in a small stream: long-term changes in richness and structure

Abstract

SummaryThe prediction that species richness and diversity of intestinal helminth communities in eels would change over time in response to habitat changes was tested over a period of 13 years in a small stream subjected to extensive human management. Nearly all measures of helminth community structure adopted indicated a decline in richness and diversity over the first 6 years followed by a recovery over the last few years to levels unexpectedly close to those at the start of the investigation. Changes in total number of species suggested that the component community was far richer (from 3–9 species) at the end of the period. By contrast, changes in diversity and dominance measures revealed less variation than expected and suggested that there was an underlying stability of community structure characterized by high dominance by a single species, although the identity of this changed, low diversity and a large proportion of the eel population harbouring 0 or only 1 species. A similar pattern of changes was recorded in the infra-communities, where values of species richness and diversity were very similar at the commencement and termination of the study. It appeared that those helminths that colonized in the recovery period contributed to community richness but had little impact on community structure. The helminth communities clearly did change in response to habitat changes, and the evidence for a fixed number of niches and an underlying constancy in helminth community structure in eels is evaluated.

Community ecology of the metazoan parasites of freshwater fishes of Kerala

“…It is to be noted in this context that the compound community of parasites (= local parasite fauna) is influenced by several factors and there could be even temporal differences in the nature of the compound communities (Holmes 1990). Further, there is evidence to show that the parasite communities of freshwater fishes are basically stochastic assemblages determined by events like chance introduction, colonization and extinction of parasites in a given region (Esch et al 1988;Hartvigsen and Kennedy 1993;Kennedy 1993). Carnivorous forms such as Channa spp., M. cupanus, Mystus spp.…”

Salinity dependence of parasite infestation in the European eel Anguilla anguilla in northern Germany

“…Conneely and McCarthy, 1986;Køie, 1988a;Kennedy, 1993Kennedy, , 1997Schabuss et al, 1997;Kennedy et al, 1998;Sures et al, 1999;Di Cave et al, 2001;Aguilar et al, 2005;Kristmundsson and Helgason, 2007). Investigations on the parasite fauna of European eels in marine habitats (Outeiral et al, 2001(Outeiral et al, , 2002Kristmundsson and Helgason, 2007) are scarce.…”

Ecologia da comunidade de metazoários parasitos do acará <em>Geophagus brasiliensis</em> (Quoy e Gaimard, 1824) (Perciformes: Cichlidae) do rio Guandu, Estado do Rio de Janeiro, Brasil

“…Em um trabalho realizado por Silva-Souza e Eiras (2002) Segundo Kennedy (1990), o número de espécies presentes nas infracomunidades parasitárias pode ser resultante de dois diferentes processos: (a) o número de espécies presentes em uma localidade particular e (b) as oportunidades de transmissão e de infecção dentro da localidade. Kennedy (1993) citou que comunidades parasitárias de hospedeiros sujeitos à influência de freqüentes alterações ambientais podem sofrer variações substanciais na sua riqueza e estrutura. Zuben (1997) mencionou que a diversidade de espécies nas comunidades parasitárias é resultado, entre outros fatores, de interações entre a história evolutiva e a ecologia dos hospedeiros e também está associada à diversidade de hospedeiros intermediários e definitivos.…”