04 February 2006

Papers read this week

Musical accompaniment: Ravi Shankar & Philip Glass: Passages.

Note: To see the Turkish characters properly please set the encoding of your browser to UTF-8. (Instructions are here.)

UĞUR KAYA, İ. ETHEM ÇEVİK, UĞUR C. ERİŞMİŞ. 2005. Population status of the Taurus Frog, Rana holtzi Werner (1898), in its terra typica: is there a decline? Turkish Journal of Zoology 29:317-319. pdf
The Taurus frog (Rana holtzi) , included in the IUCN Red List of Threatened Species, is known from only one location, Maden Lake in the Taurus Mountains, Turkey. The authors did a mark-recapture study of the frogs in 2003 and estimated the population size of the Taurus frog in Maden Lake as 725 to 1432. The species is believed to have been more abundant in the 1960s, although no quantitative data are available from that period. The authors speculate that the introduction of the common carp (Cyprinus carpio) may have been responsible for the population decline of the frogs.

JORDI FIGUEROLA, ANDY J. GREEN and LUIS SANTAMARÍA. 2003. Passive internal transport of aquatic organisms by waterfowl in Doñana, south-west Spain Global Ecology & Biogeography 12:427–436. pdf
Transport of invertebrates, especially snails, by birds has become a recurring theme on this blog (previous posts on this subject are here, here and here). In this paper, the authors recovered intact plant seeds and aquatic invertebrate eggs from 386 faecal samples of 11 species of migratory waterfowl in southwest Spain. Seeds were of at least 7 genera of plants and invertebrate eggs were of crustaceans, bryozoans and Corixidae (aquatic bugs, Heteroptera). The authors conclude that "waterfowl play an important role in the dispersal of organisms in aquatic environments by internal transport." I have one serious objection to the interpretation of their results: they did not check to see if the recovered seeds and eggs were viable! Their conclusion is weakened by their own disclaimer: "We provide data on the presence of apparently viable propagules in the droppings rather than the results of germination assays, thus our data overestimate true viability."

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