The beginning of October sees me in my final week of my stay at Cocha Cashu biological station, in the Manu National Park in South-East Peru. The tropical paradise was opened to researchers in the 70s by John Terborgh and has seen an unimaginably high number of important ecological research and brilliant minds disseminated into the scientific world. My arrival, with collaborator Harald Beck, mammologist from Towson University, botanical assistant Adrian Torres Paucar, and a boat engine that took 3 days to splutter and grumble its way up river, was heralded with the beautiful neo-tropical scenery of the Madre de Dios river complete with macaws, skimmers, jabirus, monkeys, caimen and even a tapir! BUT being a new and enthusiastic PhD student there was no time for loitering about to admire the (excessively distracting) scenery, so day 1 saw us marching out into the field to begin stage one of operation seedlings.
My research is based around tropical plant community assembly, I am aiming to find out how trophic interactions influence the seedling community, i.e. How seedling herbivores affect the change from seedling to adult community structures, and the relative importance of different herbivores in the maintenance of biodiversity. This information will then tell us how the loss of mammals (ie from hunting) and the change in herbivore communities due to anthropogenic impacts will impact the plant community diversity, and how this will affect the future of the neo-tropics and the people that rely on this system. To do this we have put great effort into excluding semi-factorially mammal, insect and pathogenic herbivores from seedling communities, in order to monitor the changes in seedling communities.
To start with we had to locate 384 seedling plots, set up by Timothy Paine 10 years previously, and last monitored 4 years previously. The plots were marked with a small iron rebar poking out of the leaf litter and potentially some ant gnawed/lichen covered flagging, needless to say when we were presented, by Lisa Davenport, with a metal detector our lives became simultaneously easier and more entertaining. Treefalls and hungry ants couldn’t stop senior metalico (otherwise known as Adrian) from ensuring a speedy and successful stage one of operation seedlings.
Stage two of operation seedling involved tagging and measuring hundreds of seedlings, it did not take me long to learn that most seedlings are not only generically small and green, but bear small resemblance to their adult counterparts. So we may not have a name for all of them yet but we can rest assured they all have decorative orange necklaces and my full care and attention for the foreseeable future!
Meanwhile life at Cocha Cashu goes on as usual; an after work canoe in the small oxbow lake by the station, containing numerous grumbling caimen, giant otters, piranhas, a cacophony of birdlife including daily kingfishers and the beautiful agami heron, and a tranquil reminder that I am in fact in one of the most beautiful places in the world, floating on a tropical lake surrounded by sights and sounds that should never be underappreciated; A chat with a young and enthusiastic, or a not-so-young-but-still-enthusiastic scientist, ready to share their stories over dinner; A free afternoon to watch birds and monkeys on the trails, or climb Cocha Cashu’s first (and second) canopy tower (courtesy of photo journalists Christian Ziegler and Joris van Alphen) embracing a fruiting Ficus.
Excluding mammals was the most time consuming and sweat, blood and tear producing. Starting out with dragging 80 9m iron rebars from the river to the station left us all exhausted and wondering what exactly we had gotten ourselves into. Following this up with cutting them all into pieces with a hack saw confirmed our worst suspicions in this regard (that is…more sweat, blood and tears to be produced). The 64 exclosures consist of 8 iron rebars holding out wire mesh strong enough to bounce a peccary (depending on the level of enthusiasm on the peccaries part), surrounding the seedling plots. One exclosure per transect had small agouti doors cut into it, so that small mammals (agouti sized and smaller) could enter but the larger, peccary sized mammals were kept out. These exclosures simulate a hunted forest where mammals such as peccaries maybe removed, but rodents would not. Operation seedling stage 3 complete.
The fourth and final stage of operations seedling 2014 saw the emergence of goggles, rubber gloves and chemical masks, ready for the application of pesticides. Insecticide, fungicide and water applied to all treatment plots to exclude insect herbivores and fungal pathogens. Nothing feels worse than killing things in the rainforest but there has been the odd occasion where it feels a bit like revenge for wasp stings, ticks, a healthy layer of blood sucking fly bites and the odd bullet ant sting (or 3 at once for the unfortunate Harald), I hope only that science will benefit from the loss of some of our 6+ legged friends, and that some fortunate seedlings appreciate their luck! I thank Noeme and Adrian for continuing to thrash about in the field with chemical masks so that my project may continue, and hope that no more karmic retributions from bullet ants come their way!