Article © Mark Sabaj Pérez, uploaded February 17, 2015.
As we begin 2015, I would like to present an update on the iXingu Project to those who generously contributed to the PlanetXingu FundRazr in 2013 and 2014.
First, a little background. Knowing that the Belo Monte dam will have a profound impact on the lower rio Xingu, a collaborative proposal to inventory the river was submitted to the US National Science Foundation (NSF) in 2010. That proposal was declined for funding - as are most first submissions to NSF. But, some of the reviews were positive, so a revised proposal was submitted in 2011. The reviews improved, but the second attempt also was declined. Not discouraged, we revised the proposal once again and resubmitted it to NSF in 2012. The third time proved to be the charm, and NSF finally approved our project for funding in February 2013.
A major criticism of our first two proposals was that it is impossible for foreign scientists to legally export biological specimens from Brazil. Although it is not easy, it is certainly not impossible if teamed up with first-rate Brazilian collaborators and institutions. We proved this on a pilot expedition to the rio Xingu in 2012, funded by charitable donations from Julian Dignall and Shewell "Bud" Keim, benefactors of ichthyology at my museum, The Academy of Natural Sciences of Philadelphia (ANSP). Our successful pilot expedition, with Xingu fishes and tissue samples deposited at the Academy and the Instituto Nacional de Pesquisa da Amazônia (INPA) in Manaus, helped convince reviewers and NSF that our experienced team could complete the proposed study.
And so, in February 2013, the iXingu Project began with funding from the National Science Foundation, Division of Environmental Biology (NSF DEB 1257813). The primary investigators (Co-PIs) are John Lundberg and myself at the Academy of Natural Sciences and Kirk Winemiller at Texas A&M University. In Brazil, Lúcia Rapp Py-Daniel at INPA and Leandro Sousa at Universidade Federal do Pará, Altamira (UFPA) are the project's primary collaborators and sponsors.
In our proposal, we scheduled three major expeditions to the rio Xingu, in the dry water season while waters are falling (September 2013), in the wet season during high water (March 2014) and in the dry season while waters are rising (November 2014). Now completed, all three expeditions were met with tremendous success.
Expeditions I, II and III and the 2012 pilot expedition yielded an estimated total of 36,624 specimens of fishes now deposited in collections at ANSP, INPA and LIA (Laboratório de Ictiologia de Altamira, UFPA). Together, the specimens represent an estimated 400 species, or about 90% of the total fish diversity known for the Xingu. The expeditions yielded an estimated 4,400 tissue samples of fishes preserved for genetic analyses. The samples were taken in triplicate and are deposited at ANSP, INPA and LIA. Expeditions I-III also yielded 2,521 tissue samples preserved for isotopic analyses of food webs, including 2,158 individual fishes, 106 mollusks and 257 miscellaneous taxa (algae, seston, sponges, leaves, insects, crustaceans). This represents perhaps the largest and most comprehensive collection of isotopic samples taken for a Neotropical River system. To the fishes are added equally impressive collections of Xingu crustaceans and mollusks deposited at INPA, Universidade de São Paulo, and the Illinois Natural History Survey. All of those collections are essential to documenting the diversity and ecology of Xingu fishes, measuring their distinctiveness from fishes in other river systems, estimating their phylogenetic placement among related taxa, and benchmarking the Xingu fauna against the eventual impacts of the Belo Monte dam.
So, how did your contributions to PlanetXingu contribute to the success of the iXingu Project? In short, those contributions allowed us to purchase valuable field equipment and supplies that were not budgeted in the NSF proposal. NSF support is limited, and projects funded by NSF are typically required to reduce the proposed budget prior to final approval. Also, equipment and supplies purchased with NSF funds are subject to overhead costs, a sort of tax that goes to the institution(s) hosting the project. For example, a $1 item costs the grant $1.60, the 60 cents going towards operating expenses of the host institution. As a result, our reduced budget only included equipment and supplies essential to the main goals of the project.
PlanetXingu funds were used to purchase supplemental equipment and supplies that granted us the freedom to experiment a bit with new techniques. For example, Leandro Sousa hypothesizes that certain loricariids prefer certain water depths during the day. But, collecting good data on depth of capture is difficult. Our fishermen typically dive for 45 minutes, during which they may catch dozens of individuals at various depths. On our most recent expedition, each diver was equipped with a head-mounted GoPro camera and instructed to film his dive watch (which displays depth) upon the capture of each specimen. Such footage will enable Leandro to precisely quantify the depth of capture of various loricariids, and thereby test his hypothesis. This technique also is useful for documenting the microhabitats of loricariids. Furthermore, this new technique is likely to become a standard for investigating the habitat distribution of loricariids and other fishes in Neotropical rivers. Our development of this technique was made possible by GoPro cameras and equipment purchased with PlanetXingu funds.
Another exciting experiment involved the use of a camera-equipped quadcopter (DJI Phantom 2 Vision+) to document the rio Xingu from high above. Quadcopters are fast becoming important research tools, particularly for ecologists and geologists. Quadcopters provide a relatively inexpensive way to take aerial photographs and videos to map and study various landscapes. For example, quadcopter images may prove useful for ground-truthing satellite data used to map vegetation, making sure interpretations are consistent with what's actually on the ground. We successfully employed a quadcopter on our latest expedition and recorded some stunning views of several rapids in the Xingu and its tributary the Iriri. The footage archives the pristine nature of those rivers prior to the completion of Belo Monte, and helps us to appreciate the true complexity and grand scale of such habitats. Fortunately, the completion of Belo Monte has been delayed by at least one year. This will allow us to record more quadcopter footage of the rio Xingu on another trip scheduled for August 2015. Again, funds raised via PlanetXingu gave us the opportunity to purchase that equipment and record such valuable images.
PlanetXingu funds were also applied to the purchase of a gasoline-powered BAUER compressor to fill SCUBA tanks in the field. Much of Leandro's work in the Xingu involves SCUBA diving, and re-filling tanks is impossible in the field without a portable compressor. The new compressor will enable Leandro to spend more SCUBA time in remote field locations.
Finally, PlanetXingu funds were used to purchase a variety of cameras and related equipment that we routinely use in the field. Leandro and I are both avid photographers. We dedicate much of our field time to capturing high quality photographs of fishes and habitats for print publications and the Internet. We are continually testing new equipment and techniques for improving our photography, and PlanetXingu contributed significantly to those efforts.
We originally intended to apply PlanetXingu funds towards the purchase of a $6,000 flow meter to measure current velocities in habitats frequented by various loricariids. Before committing to such a large expense, we decided to field test the same model flow meter using one loaned to us by Kirk Winemiller at TAMU. On Expedition III, we soon realized that the structure of typical pleco habitat in the Xingu was too complex to be accurately and precisely surveyed by such a flow meter. The impeller was simply too large and awkward to be used precisely, or obstructed the natural flow through tight crevices and cavities, so as to give a dubious reading. As such, we had serious doubts about the quality of data we could gather concerning the flow rates of preferred pleco habitats. Nevertheless, using the TAMU flow meter, Michael Hardman conducted a small field study in a side channel containing the common Xingu plecos. Hardman measured and filmed mean flow rates and habitat complexity, respectively, to provide a snapshot of those parameters during the late-stage dry season. A summary of that study will be made available in due course. Suffice it to say, the flow meter we intended to buy with PlanetXingu funds did not perform as well as expected. So, we decided to apply the funds elsewhere.
In 2015, project collaborators will begin sorting through and analyzing the specimens and data collected in the first two years of the project. We have a lot of work to do, but an excellent team to accomplish our primary goals. Ultimately, we plan to publish complete inventories of the fishes, crustaceans and mollusks of the lowermost Xingu alongside keys to their identification and data on their distribution and ecology.
Your contributions to PlanetXingu have significantly enhanced our work. We are truly grateful to Julian Dignall for facilitating PlanetXingu. He did so in the spirit of bringing together communities of ichthyologists and aquarists with shared interests in the documentation of aquatic diversity. Towards that effort, we have disseminated the results of our work via personal communications, presentations, popular articles, and websites including the iXingu Project Facebook Group. We have much more to share, and will continue to do so! It has been our great pleasure to meet and interact with many of you, and we appreciate your positive feedback. I am honored by your interest in our work. Moreover, I am routinely impressed by the knowledge of Neotropical fishes among aquarists, and have learned much. Like Julian, we dearly hope PlanetXingu is the first of many successful initiatives that bridges gaps between aquarists and scientists, to the benefit of all.
From the iXingu Project collaborators, thanks to all for your generous support.
Mark Sabaj Pérez
Co-Principal Investigator, iXingu Project
12 February 2015
Back to General Articles index.