Amazon Rainforest Expedition: Pampas del Heath – Islands of Grass
A 21-day research expedition to the Pampas del Heath, Peru’s version of the Pantanal, situated at the eastern edge of the Bahuaja Sonene National Park. This unique ecosystem for Peru, consisting of two small islands of tropical grassland, peppered with termite hills, embedded in thick lowland Amazon rainforest lies near the Heath River – which doubles as the principal access route. The Pampas are home to habitat-restricted endemics and endangered species such as Maned wolf (Chrysocyon brachyurus), Marsh deer (Blastocerus dichotomus), White woodpecker (Melanerpes candidus), Red-shouldered macaw (Diopsittaca nobilis), to name but a few. Large specimens of Anaconda and Tapir have also been observed at close range on past trips to the area. Associated oxbow lakes close to the Heath River are home to noisy families of Giant river otter (Pteronura brasiliensis), although some of these lakes are now infested with another giant, the Paiche (Arapaima gigas) – a large predatory fish introduced to Lake Sandoval, near Puerto Maldonado, in the 1960s. The expeditionary team’s aim on this occasion is to collect further evidence of the population size of the community of endemic and endangered species that inhabit the Pampas, with an emphasis on previously unstudied locations in both of the grass islands (Juliaca and Picoplancha). Data will also be collected on the presence and abundance of Giant otters and Paiche fish on at least five lakes, to determine whether they continue to be essential habitat for the former and whether or not the latter have reached an abundance that merits population control measures.
Colonel Percy Fawcett, a British geographer and explorer, was one of the first to describe the Pampas grasslands along the Heath River during his work to locate the source of the river and to map the official border line between Peru and Bolivia back in 1910, at the height of the rubber boom in Amazonia. At that time the border was not well defined. As a consequence, bands of rubber boom tycoons and their private armies, allied to either Peru or Bolivia, would fight each other periodically for control of the best tracts of rubber-tree dominated forest, most which lay in and around Tambopata. On his trip up the Heath River, Fawcett encountered bands of Ese’eja tribes’ people, whom he befriended with the aid of live musical presentations on the beach. Shortly afterwards the Ese’eja of the Heath River were slowly encouraged to move out of the forest and into more permanent settlements around Dominican missionary stations near the mouth of the river. These subsequently morphed into what are now the Sonene and Palma Real native communities, which together have a population of 300 people. The Ese’eja are the reason the two Pampas del Heath grasslands, the northern one of which is called Picoplancha and the southern one Juliaca, are still flourishing.
Explaining the continued persistence of the Pampas del Heath, where strong evidence exists that they should have been swallowed up by encroaching forest long ago, is important from a Peruvian biodiversity conservation point of view, as it has long-term repercussions for how these grasslands must be managed as well as periodic negative consequences on wildlife and people. A large number of species, registered as nationally-endangered, are only to be found in the Pampas del Heath, so their conservation is a national priority. These flag-ship species include the Maned wolf (Chrysocyon brachyurus), Marsh deer (Blastocerus dichotomus), White woodpecker (Melanerpes candidus), Red-shouldered macaw (Diopsittaca nobilis), Toco toucan (Ramphastos toco), and White-winged shrike-tanager (Lanio versicolor), to name but a few. The Pampas, riverine, and oxbow-lake habitats of the Heath River are also home to large specimens of Anaconda (Eunectes murinus) and Tapir (Tapirus terrestris), observations of which will be recorded and filmed as they are also two of Tambopata’s conservation priority species.
What’s so special about the Pampas del Heath?
The secret to the success of the Pampas turns out to be fire. Be it sparked by random lightning or more commonly a premeditated flint strike (or nowadays a lighted match) in the hands of a native Ese’eja, it is fire that has given life and shape to the Pampas del Heath as we know it. Without the periodic elimination of tree seedlings and seeds embedded in the turf, the grass would quickly become shaded out from the edges, and a stunted community of trees, giant pineapple-like bromeliads, tree ferns, banana-like Phenakospermum plants, and Aguaje (Mauritia flexuosa) palms would begin to dominate. In time, even this community would give way to a more normal assemblage of forest tree species, if there is such a word as normal with over 1,000 tree species in Tambopata.
Over the last twenty years or so, the northern Picoplancha Pampa has been partially burned on only a few occasions, whilst the southern Juliaca Pampa has been much more heavily managed, with burning on average every two years. The last major burn of the latter occurred in mid 2010, when about ¾ of the grassland was burnt by a run-away fire that lasted several days. The fire management regime of Picoplancha and Juliaca is still relatively haphazard, and it is still uncertain what the optimal regime should be for each in order to maintain their underlying ecology, biodiversity, and persistence of flag-ship endangered species. With too little burning, as might be the case with Picoplancha, the forest will begin to overtake the grass. With too frequent burning, especially if done over large areas, some populations could be wiped out making it much harder for them to re-establish afterwards based solely on immigration from other areas. Therefore, monitoring wildlife populations before and after burning episodes is important, in order to gauge the relative benefits and impacts of each burning regime on each Pampas. Pampas burning also generates huge amounts of smoke and air pollution. Prevailing winds bring this smoke and pollution over Tambopata and other areas of south-western Amazonia, significantly reducing visibility levels and affecting people’s health through increased incidence of respiratory problems, such as asthma. The information to be collected on this expedition, when married to that of previous expeditions and future ones to come, will go a long way towards identifying the optimal burning regime – with the added benefits that this will have on reducing smoke and air pollution to a minimum.
One of the research questions that the bird team on the expedition will endeavour to answer is how much movement there is between the Picoplancha and Juliaca Pampas with regards to certain keystone bird species. This will be accomplished by catching, banding, and recapture of birds. Numerous individuals were banded on a previous expedition to the Juliaca Pampa in 2011.
As part of ongoing efforts to monitor Giant otter populations across south-eastern Peru, that began in the 1980s and subsequently led by the Frankfurt Zoological Society, and also the spread of the introduced Paiche fish, the team will also comb five oxbow lakes using inflatable paddle canoes taking notes on signs and direct observations of these two species. During this process, close encounters with Anaconda, Black caiman (Melanosuchus niger), Hoatzin (Opisthocomus hoazin), Boat-billed herons (Cochlearius cochlearius), and if you’re especially quiet a Sunbittern (Eurypyga helias) or two are very possible.