Deriving the potential of natural puna vegetation

It has been an exciting 15 months in Latin America, filled with stories of challenging mountain ascents and new botanical discoveries. My PhD study is focused on trying to derive the potential natural vegetation of the Andean high altitude grasslands known as ‘puna’ which have been burnt and grazed consecutively over the past 10,000 years. This disturbance has yielded a largely man-made vegetation making it difficult to pinpoint what the puna would look like without this influence.

The study is innovative as, being both an aspiring botanist and an experienced mountaineer, I have mixed my climbing and botanical skills to access and study sites that have an untouched flora which would likely grow throughout the puna grasslands if not for annual fires and cattle grazing. All past studies looking at effects of burning and grazing on paramo and puna have failed to provide baseline data on what the vegetation would actually look like should there be no human influence. This makes the present study unprecedented in its field, and it is hoped the data will provide important information for conservation planning and management in the region.


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Basecamp and slope site 1 with Contorkayqu tower in background.

My fieldwork focuses on the Cordillera Vilcanota in Southern Peru. Numerous sites have been found which are perfect for the study with all being above 4000m above sea level (asl) and most requiring a 1-2 day walk-in. On an average trip myself, assistant and camp cook spend 2 weeks camping at the sites where we scale the cliffs daily in search of inaccessible ledges with zonal vegetation and a well developed soil. The vegetation is studied using quadrats, and soil samples are taken from the ledges whilst quadrats and soil samplesare also taken on the grazed, burnt slopes below.

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As predicted, stark differences have been observed between the vegetation on the inaccessible ledges and that found on the grazed slope sites. There is a higher diversity of flora on the grazed sites whilst both rarely collected and new species have been found on the ledge sites. At least five new species of grass have been found and there are many other specimens that need to be sent to experts to be sure that they are new discoveries. Excitingly, we are also close to confirming the discovery of the highest forests in the world. Whilst during fieldwork we regularly climbed to above 5000m asl and have identified forests of Polylepis subsericans at these altitudes. There are likely to be many more new discoveries during the next six months of fieldwork.

Steven Sylvester

Steven was awarded a Study Abroad Studentship in 2010.