1,721,072 research outputs found
Parasites through time. Museum collections as a tool for parasite conservation and ecosystem health monitoring.
No full textHow flatworm parasite communities changed in response to human-induced ecosystem perturbations in Lake Victoria
No full textGlobal change is causing distribution shifts and population declines of countless plants and free-living animals. How parasites are affected by global change is largely unknown, despite their ubiquity and importance for ecosystem functioning (e.g. regulation of host populations, increase of food web connectivity). Human-induced environmental changes are expected to alter parasite abundance and host-parasite interactions (e.g. spillover to novel host species), but the direction of such changes is unclear.
Lake Victoria, the youngest of the African Great Lakes, is a biodiversity hotspot that experienced simultaneous drastic anthropogenic changes: multiple invasions (e.g. Nile perch), eutrophication and overfishing. We use historical fish collections – harboring a hidden parasite collection – to test whether parasite abundance and host range changed in response to anthropogenic changes in Lake Victoria. We analysed ectoparasite infection in 13 cichlid fish species, representing 7 eco-morphological groups, sampled between 1973 and 2014.
Overall parasite abundance, but not parasite diversity, declined after impacts on Lake Victoria. Most ectoparasite species are declining, while few others are increasing in abundance, indicating that parasite species respond differently to ecosystem disturbances. The host range of most ectoparasitic flatworms changed, as they disappeared from some host species and colonized few new host species that they did not infect before ecosystem changes in Lake Victoria. This may suggest that ecosystem disturbances favor host switching.
Since changes that have occurred in Lake Victoria are also occurring in other ecosystems, our results suggest that we can use flatworm parasites as sentinel for ecosystem health, which might contribute to better strategies for linking conservation and ecosystem health.Swiss National Science Foundation (SNSF
Temporal changes in the flatworm parasite communities of Lake Victoria cichlid fishes in response to ecosystem changes
No full textSpecies interactions are particularly crucial for ecosystem health and for conservation in face of global change. Human-induced environmental changes may influence the host-parasite interactions and may lead parasites to expand their host range (i.e. spillover to novel host species). Although parasites contribute to maintain ecosystem health, it is often overlooked how parasite community structure changes in response to ecosystem changes. We investigate this in flatworms parasitizing cichlid fish in Lake Victoria.
Lake Victoria, the youngest of the African Great Lakes, is a biodiversity hotspot that experienced simultaneous drastic anthropogenic changes: multiple invasions (e.g. Nile perch), eutrophication and overfishing. We use recent and historical fish collections to assess whether the communities of parasitic flatworms changed after such ecosystem perturbations in Lake Victoria. We analysed flatworm parasite infection in 12 cichlid fish species, representing 7 eco-morphological groups, sampled between 1973 and 2014. We identified 6 species of monogeneans (1 Gyrodactylus and 6 Cichlidogyrus, which 4 are new to science) and 2 species of copepods.
An overall decrease in parasitic flatworm diversity was not observed. Instead, some flatworm parasite species are declining, while others are increasing in abundance, indicating that parasite species respond differently to ecosystem disturbances. Moreover, some flatworm species are becoming more generalists, infecting hosts species that they did not infect before ecosystem changes in Lake Victoria. This may suggest that ecosystem disturbances favor host switching.
Since changes that have occurred in Lake Victoria are also occurring in other ecosystems, we can use flatworm parasites as sentinel for ecosystem health, which might contribute to better strategies for linking conservation and ecosystem health.Swiss National Science Foundation (SNSF
How flatworm parasite communities changed in response to human-induced ecosystem perturbations in Lake Victoria
No full textGlobal change is causing distribution shifts and population declines of countless plants and free-living animals. How parasites are affected by global change is largely unknown, despite their ubiquity and importance for ecosystem functioning (e.g. regulation of host populations, increase of food web connectivity). Human-induced environmental changes are expected to alter parasite abundance and host-parasite interactions (e.g. spillover to novel host species), but the direction of such changes is unclear.
Lake Victoria, the youngest of the African Great Lakes, is a biodiversity hotspot that experienced simultaneous drastic anthropogenic changes: multiple invasions (e.g. Nile perch), eutrophication and overfishing. We use historical fish collections – harboring a hidden parasite collection – to test whether parasite abundance and host range changed in response to anthropogenic changes in Lake Victoria. We analysed ectoparasite infection in 13 cichlid fish species, representing 7 eco-morphological groups, sampled between 1973 and 2014.
Overall parasite abundance, but not parasite diversity, declined after impacts on Lake Victoria. Most ectoparasite species are declining, while few others are increasing in abundance, indicating that parasite species respond differently to ecosystem disturbances. The host range of most ectoparasitic flatworms changed, as they disappeared from some host species and colonized few new host species that they did not infect before ecosystem changes in Lake Victoria. This may suggest that ecosystem disturbances favor host switching.
Since changes that have occurred in Lake Victoria are also occurring in other ecosystems, our results suggest that we can use flatworm parasites as sentinel for ecosystem health, which might contribute to better strategies for linking conservation and ecosystem health.Swiss National Science Foundation (SNSF
Temporal changes in the flatworm parasite communities of Lake Victoria cichlid fishes in response to ecosystem changes
No full textSpecies interactions are particularly crucial for ecosystem health and for conservation in face of global change. Human-induced environmental changes may influence the host-parasite interactions and may lead parasites to expand their host range (i.e. spillover to novel host species). Although parasites contribute to maintain ecosystem health, it is often overlooked how parasite community structure changes in response to ecosystem changes. We investigate this in flatworms parasitizing cichlid fish in Lake Victoria.
Lake Victoria, the youngest of the African Great Lakes, is a biodiversity hotspot that experienced simultaneous drastic anthropogenic changes: multiple invasions (e.g. Nile perch), eutrophication and overfishing. We use recent and historical fish collections to assess whether the communities of parasitic flatworms changed after such ecosystem perturbations in Lake Victoria. We analysed flatworm parasite infection in 12 cichlid fish species, representing 7 eco-morphological groups, sampled between 1973 and 2014. We identified 6 species of monogeneans (1 Gyrodactylus and 6 Cichlidogyrus, which 4 are new to science) and 2 species of copepods.
An overall decrease in parasitic flatworm diversity was not observed. Instead, some flatworm parasite species are declining, while others are increasing in abundance, indicating that parasite species respond differently to ecosystem disturbances. Moreover, some flatworm species are becoming more generalists, infecting hosts species that they did not infect before ecosystem changes in Lake Victoria. This may suggest that ecosystem disturbances favor host switching.
Since changes that have occurred in Lake Victoria are also occurring in other ecosystems, we can use flatworm parasites as sentinel for ecosystem health, which might contribute to better strategies for linking conservation and ecosystem health.Swiss National Science Foundation (SNSF
Parasites through time. Museum collections as a tool for parasite conservation and ecosystem health monitoring.
No full textChanges in parasite community structure may elucidate causes for ecosystem decline in Lake Victoria
No full textHuman-induced environmental changes may influence the host-parasite interactions and may lead parasites to expand their host range (i.e. spillover to novel host species). Lake Victoria, the youngest of the African Great Lakes, is a biodiversity hotspot that experienced drastic anthropogenic changes since the 1950s: multiple invasions (e.g. Nile perch), eutrophication, overfishing. Such ecosystem perturbations occurred simultaneously and led to a rapid decline of biodiversity (halving haplochromine species in few decades) and to an overall reduction in complexity, with consequences also on human health (e.g. emerging infectious diseases).
Although parasites contribute to maintain ecosystem health, it is often overlooked how parasite community structure changes in response to ecosystem changes. We expect that low host specificity and host switches are favoured in disturbed ecosystems (we already found indications for this pattern in cichlid fish of Lake Victoria). We aim to understand if recent changes in host specificity of monogenean parasites in Lake Victoria resulted from a natural state of the lake or if it has been recently induced by human disturbances. We use historical collections to detect recent changes in the structure of fish parasites in Lake Victoria. To disentangle which perturbation (eutrophication, Nile perchpredator invasion) mainly caused such changes, we use a space-for-time approach in which we model parasite shifts across lakes that share parasite species as well as closely related cichlids but that differ in disturbance.
Since perturbations that have occurred in Lake Victoria are also occurring in other ecosystems, we can use the changes in host ranges of parasites as sentinel, to better monitor and hence conserve ecosystem health elsewhere.Swiss National Science Foundation (SNSF
Worms of change: anthropogenic disturbance changes the ectoparasite community structure of Lake Victoria cichlids
No full textHost-parasite interactions increase the complexity, and thus robustness and resilience, of an ecosystem. This role is particularly relevant in global change times. Environmental changes cause biodiversity loss and shifts in community compositions of free-living organisms, but how these changes affect parasite communities is still unclear. We tested how parasites respond to anthropogenic perturbations, using the Lake Victoria case (East Africa), after 40 years of their onset. Lake Victoria experienced multiple human-induced invasions (e.g. Nile perch), eutrophication, which heavily affected haplochromine cichlid fishes (whose species richness decreased from 500 to 250 species in a decade). We compared gill macroparasite communities of 13 haplochromine species before and after perturbations, using historical and recent fish collections. The host-parasite network rearranged in a way that buffers the impact of perturbations, indicating resilience. However, the host range of parasites, which is linked to resilience ability, decreased and thus we expect a decreased resilience ability in the future. We also found a decrease in infection parameters, co-infection occurrence, and biodiversity indices highlighting the urgent need of a conservation plan for wildlife parasites, to preserve their ecosystem services in face of global change. This study serves as a proof-of-concept of how often overlooked aspects of host-parasite interactions provide a tool to monitor the health status of an ecosystem
A failure to diversify on a surface of exchange: the case of Dolicirroplectanum lacustre, the monogenean parasite infecting African latids
No full textIntraspecific diversification and mitonuclear discordance in the monogenean parasite Dolicirroplectanum lacustre, co-introduced with the invasive Nile perch
No full textParasites typically speciate faster, and become more species-rich than their hosts. This especially holds in large and long-lived hosts. Most African lates perches (Latidae), some of the largest freshwater fishes, host only a single monogenean flatworm: Dolicirroplectanum lacustre. This parasite has 'failed to diverge', but displays high morphological variability, with two morphotypes identified.
The Nile perch (Lates niloticus) is a notorious invasive species. The introductions of Nile perch from lakes Albert and Turkana into lakes and rivers in the Lake Victoria region led to the impoverishment of the trophic food webs, particularly well documented in Lake Victoria. Along with the introductions of the Nile perch, its parasites were co-introduced.
To investigate the pattern of parasite co-introduction, we studied the intraspecific diversity of D. lacustre from Nile perch in Lake Albert and Lake Victoria by assessing morphological and genetic differentiation. A single morphotype is suggested to be co-introduced in Lake Victoria. Based on our results, we reported reduced genetic and morphological diversity in Lake Victoria, resulting from a founder effect. The diversification in the COI mitochondrial gene portion was directly linked with the morphotypes, while the nuclear gene portions indicated conspecificity. Mitonuclear discordance within the morphotypes of D. lacustre indicates an incomplete reproductive barrier between the morphotypes
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