In addition to surveys and call recordings, this year we are also filtering stream water to screen for the presence of species that have gone missing since the mid 2000's following the outbreak of chytridiomycosis in the region. There are at least 19 species that have not been seen in over 10 years, especially in the cloud forest at mid-elevations (in the Andes that means around 1500-2000 m). Among them the harlequin toad Atelopus erythropus and the glassfrog Nymphargus truebae illustrated below. The majority of missing species are stream-breeding amphibians.
The idea is to extract DNA from the filtered water and amplify gene sequences to detect and quantify the presence of DNA from target species through real time PCR. This technique will complement our visual and auditory surveys -- which so far have failed to confirm the presence of our target species in recent years. This week we have been collecting water samples from several creeks and filtering these samples either at the collecting site or in the lab. Of course what seems a very straightforward thing to do can generate its own complications in the field. In addition to the rain that can fall at any time during the day and turn bucolic streamlets into raging (and turbid --quickly clogging the filter) torrents, our fantastic pumping equipment (a manual vacuum pump) failed spectacularly after the fourth or fifth stream.
Without a pump it is impossible to filter the water, and after a short period of despair for the loss of our manual pump, Alex who by now knows quite a bit about Shigella (see previous post) proposed to use the old gas pump from the rugged car (I carry several replacement parts in the car). The new setup works better and faster that the manual pump, although we are still working on getting a reliable and durable source of power for the pump (taking the battery of out the car every time would just be annoying) -- we are using flash batteries for now. We hope to find some of those missing species -- stay tuned for preliminary results once we analyze the samples.
News from the lab