Promoting the Values of the Llanos de Moxos Biocultural Landscape, Bolivia: Part 4

By Rob Wallace | January 19, 2025

By eight in the morning the heat in the pampas is already almost intolerable and birds like this red-capped cardinal (Paroaria gularis) are seen panting during rest. Photo credit: Rob Wallace ©️WCS.

Last year, there was a devastating and unprecedented heat wave and drought that afflicted large parts of the Amazon basin. The Llanos de Moxos did not escape this event, and on the third scientific expedition to the Llanos de Moxos, temperatures exceeded 40°C/104°F most of the time, which visibly affected wildlife from sunrise onwards.

Songbirds panted in the heat at eight in the morning. Reptiles struggled in the mud. All wildlife desperately sought water as the searing, relentless heat settled into the tropical savannas. A smoky and hazy atmosphere suffused the landscape due to widespread fires elsewhere in the Amazon, as well as a few local ones nearby.

The northern portion of the Llanos de Moxos in the Beni Departments is characterized by Cerrado vegetation — a mix of grasslands, shrub vegetation and drier tropical rainforests. Photo credit: Rob Wallace ©️WCS.

This trip focused on an area around the Benicito, Biata and Yata rivers in the Santa Rosa del Yacuma municipality. Broadly speaking, the Yata River divides the somewhat more humid and lower-lying classic Llanos de Moxos grasslands and wetlands to the south, and the drier more fire-resistant Cerrado vegetation to the north.

“Perhaps the most important threat to this ecosystem is the growing use of intense and extensive fires by landholders to improve pasture quality.”

Within the national protected area system, this Cerrado vegetation is very poorly represented, highlighting the huge importance of subnational protected areas for the future of this ecosystem in Bolivia. Perhaps the most important threat to this ecosystem is the growing use of intense and extensive fires by landholders to improve pasture quality in an area dedicated to cattle ranching.

As waters receded or dried up, animals such as this caiman concentrated around diminishing water holes. Photo credit: Rob Wallace ©️WCS.

Thankfully, at the first study site along the Benicito River we were able to observe a healthy population of cock-tailed flycatcher (Alectrurus tricolor), as well as several individuals of the streamer-tailed flycatcher (Gubernetes yetapa), both of which are considered indicator species for the health of the natural grasslands. Frequent sightings of giant anteater (Myrmecophaga tridactyla) and pampas deer (Ozotoceros bezoarticus) also suggest that despite the local fires, these grasslands and the surrounding forests hold significant conservation value.

In the riverine forests that connect with large swathes of Amazonian forests, our ornithologist, Victor Hugo Garcia, was excited to register several species that had not previously been recorded this far south in Bolivia, including the pied puffbird (Notharchus tectus) and the Peruvian recurvebill (Syndactyla ucayalae).

Some larger animals can adapt to the heat by adjusting their activity periods to the coolest times of the day. This giant anteater (Myrmecophaga tridactyla) bumped into a tent in one of the camps before six in the morning. Photo credit: Rob Wallace ©️WCS.

We prioritized this area for an expedition for a few reasons. Firstly, it is an area of the Llanos de Moxos with very little biological data. On this trip alone, ichthyologists Takayuki Yunoki, Reinaldo Cholima, and Aldo Echeverria from the Aquatic Resources Research Center (CIRA) of the Autonomous Beni University, along with WCS staff, were able to register seven new fish species for Bolivia, including a couple of especially small catfish that live in submerged logs and branches in the river and streams of the region.

“Visiting this area, generating more robust data, and publishing a summary document will hopefully further encourage local actors to take formal steps toward protecting it.”

Meanwhile, herpetologist Gabriel Callapa grew excited upon spotting a chunky lava lizard living in association with termite mounds on the grasslands. Could it be a new species for science, he wondered. Indeed, it was. Though Brazilian colleagues beat Gabriel to publication of news of a new lizard species — Tropidurus madeiramamore — roughly a month after we returned from the expedition, it was nonetheless a new record for Bolivia.

The Llanos de Moxos is home to hundreds of shallow lakes which reduce in size during the dry season. This was especially evident in the 2023 drought. Photo credit: Rob Wallace ©️WCS.

Another reason for choosing this location was its lack of sufficient archaeological investigation. While Geraldine Fernandez from the University of Bonn did not find any major earthwork structures as in many other areas of the Llanos de Moxos, she did identify a series of locations holding ceramics of a similar style to one of the sites from the Grandes Lagos Tectonicos de Exaltacion further east — suggesting a historical connection between people in these places.

Finally, several municipal authorities and ranchers had expressed an interest in either the extension of the Pampas del Yacuma Municipal Protected Area to cover this area, or the creation of a neighboring protected area. Visiting this area, generating more robust data, and publishing a summary document will hopefully further encourage local actors to take formal steps toward protecting it and strengthening its resilience to drought and fire long into the future.

Rob Wallace is Director of the Llanos de Moxos Biocultural Landscape and the Greater Madidi-Tambopata Landscape Conservation Programs of WCS in Bolivia.