Occurrence and effect of trematode metacercariae in two endangered killifishes from Greece.

We report digeneans (Diplostomidae, Crassiphialinae) in the endangered freshwater fishes Valencia letourneuxi and Valencia robertae, endemics of Western Greece. Digenean metacercariae occurred in two forms in the abdominal cavity, excysted and encysted, the latter attached to the gonads, liver and alimentary tract. Parasites were, using morphological and molecular techniques, identified as two representatives of Crassiphialinae, specifically part of the Posthodiplostomum-Ornithodiplostomum clade. The spatial, seasonal, and age class variation in parasite prevalence was examined. Autumn parasite prevalence varied between the six populations sampled (18.2 to 100%). Seasonal prevalence at the two sites sampled quadannually peaked in autumn and reached its lowest value in spring; prevalence increased with size to 100% in young adult fish. We did not find a correlation between prevalence and host sex. Overall parasites' weight averaged 0.64% of the host's, while parasite weight increased with host weight. A comparison of relative condition and hepatosomatic and gonadosomatic indices of infected and metacercariae-free specimens showed that infection did not have a significant effect on host body condition and reproduction. Regarding the parasite's life cycle, planorbid gastropods are proposed as potential first intermediate hosts in view of the host's diet and occurrence data of molluscs in the ecosystem. This is the first record of a diplostomid digenean in valenciid fishes and of representatives of the Posthodiplostomum-Ornithodiplostomum clade in a native Greek freshwater fish. Our findings are discussed in conjunction to fish conservation interventions, since parasites may contribute to the decline of endangered species.

Assessing environmental degradation of montane riparian zones in Greece.

A survey of 218 woody vegetation plots at 109 streamside sites was undertaken to describe anthropogenic degradation of riparian zone woodlands in the mountains of mainland Greece. Two assessment indices and specific anthropogenic pressure variables were employed and they showed good correlations at both the site and river segment scales. It was demonstrated through the Spanish Riparian Forest Quality Index (Qualitat de Bosc de Riber: QBR) that most riparian zones were in moderate or good condition, although extremely few sites were of high ecological status. Most riparian sites were affected by several anthropogenic pressures, some pressures produce notable degradation beyond the site-scale (i.e. at the river segment scale). This work provides a summary of the first wide-ranging vegetation-based assessment of montane riparian zones in Greece; the results support the use of site-based rapid assessment protocols along-side aquatic ecological status surveys.