Área Natural de Manejo Integrado San Matías: A Continental Mosaic of Wetlands and Savannas

The idea to protect the San Matías territory first appeared in the 1995 Land Use Plan (PLUS) of the Santa Cruz Department, which identified the area as a Reserve of Immobilization because of its exceptional ecological features and its importance for safeguarding the Chiquitano dry forest, the Bolivian Pantanal, and the Cerrado. Following this designation, the Noel Kempff Mercado Natural History Museum, the Prefecture of Santa Cruz, and the National Directorate for Biodiversity Conservation, with the support of the World Wildlife Fund (WWF), conducted studies and developed the technical proposal that led to its formal establishment.

On July 31, 1997, the Área Natural de Manejo Integrado San Matías was officially created through Supreme Decree 24734 as part of Bolivia's National System of Protected Areas. The original objective was the protection of the Bolivian Pantanal, but the area was subsequently expanded to include significant portions of the Chiquitano dry forest and the Sunsas mountain range.

In 2001, San Matías received international recognition when it was declared a Wetland of International Importance under the Ramsar Convention. This designation highlighted the area's critical role in regional hydrology and its exceptional value as one of the most important tropical wetland complexes in South America.

The ecological identity of San Matías centers on the convergence of three major ecoregions: the dry Chiquitano forest, the Pantanal wetlands, and the Cerrado savannas. This convergence produces a remarkable habitat mosaic that includes seasonally flooded grasslands, permanent and temporary lagoons, gallery forests, cerrado woodlands, dry deciduous forests, and elevated rocky outcrops.

Strong seasonal contrast defines the ecological rhythms of the area. The rainy season, which extends roughly from November through March, swells waterways and floods vast stretches of lowland savanna, while the dry season, from May to September, reduces wetlands to fragmented pools and parches the open landscapes. This cyclical drought-flood dynamic shapes vegetation patterns, animal behavior, and reproductive cycles across the entire protected area.

Vegetation varies strikingly across habitats. The Chiquitano dry forest is dominated by legume-rich families such as Fabaceae, Bignoniaceae, and Mimosaceae, with characteristic species including morado, tajibo, curupaú, cuta, and alcornoque. The Cerrado portions of the area feature grasses, Vochysiaceae-dominated woodlands, and a notable presence of endemic cacti and bromeliads. Wetland margins host palm stands of carandá and aquatic species such as Victoria regia and tarope. The botanical diversity of the area has been recognized for its high levels of endemism, especially within the herbaceous and shrubby strata.

ANMI San Matías is home to one of the most diverse faunal assemblages in Bolivia, reflecting the overlap of three major biogeographic regions. Among the most emblematic mammals are the lowland tapir, the maned wolf, the jaguar, the giant armadillo, the giant otter, the marsh deer, the pampas deer, and the white-lipped peccary. The combination of floodplains, dry forests, and cerrado habitats allows species typical of very different ecosystems to coexist within the same protected area.

Birdlife is equally impressive. The area hosts dozens of conservation-relevant species, including the hyacinth macaw, the jabiru stork, and a wide variety of wetland and forest birds. Reptiles such as the spectacled caiman and Caiman yacare are common in the waterways, while amphibians thrive in both aquatic and terrestrial habitats. According to documented inventories, hundreds of bird species, nearly 500 mammal species, and more than 120 amphibian species are believed to inhabit the area, though ongoing research continues to refine these figures.

The presence of flagship and threatened species is one of the defining conservation values of the protected area. Species such as the giant otter, the marsh deer, the hyacinth macaw, the maned wolf, and the giant armadillo highlight the area's importance as a refuge for South American wildlife facing regional population declines.

The conservation significance of ANMI San Matías lies in its protection of three globally important ecoregions within a single contiguous area. As the largest protected area in Bolivia's lowlands after Kaa Iya, San Matías plays a strategic role in safeguarding the Bolivian share of the Pantanal, the world's largest tropical wetland system, while also protecting extensive tracts of Chiquitano dry forest and cerrado habitats. Its designation as a Ramsar site in 2001 gave the wetlands international recognition and enhanced protection status.

The area also serves as a critical refuge for endangered and vulnerable species. The presence of healthy populations of jaguars, giant otters, hyacinth macaws, marsh deer, and giant armadillos gives it outsize importance for South American biodiversity conservation, especially as surrounding landscapes face increasing human pressure. Its watersheds contribute to regional hydrological balance, supporting downstream ecosystems in both Bolivia and Brazil.

Conservation in San Matías is complicated by multiple overlapping pressures. Poaching, illegal logging, unregulated commercial fishing, mining concessions, wildfires, and extensive cattle ranching all threaten the integrity of the area. Additionally, expanding road infrastructure, including the controversial Transpantanera route, risks opening previously remote habitats to settlement, extractive activities, and further deforestation. Effective management therefore depends not only on ecological strategies but also on addressing governance, Indigenous rights, and regional development pressures.

San Matías is not only an ecological landscape but also a deeply human one. The area and its surrounding zone of influence are home to 26 Indigenous communities, of which 22 are Chiquitano communities established through regional migrations over generations. Santo Corazón, founded in 1760, stands out as one of the oldest and most historically significant Chiquitano settlements in the region. Four Ayoreo communities, consolidated in 1999 as the Guayé Indigenous Territory (TIOC Guayé), represent a more recent but deeply rooted Indigenous presence.

Land tenure in many of these communities follows communal ownership patterns, and social organization blends the modern Territorial Base Organization (OTB) system with traditional Indigenous structures led by a cacique. Chiquitano communities are represented through organizations such as CIRPAS, CICHGB, and the broader Chiquitano Indigenous Organization (OICH), while Ayoreo communities belong to CANOB.

In addition to Indigenous communities, the area has historically hosted mestizo populations, Jesuit and Franciscan mission settlements, and a notable presence of Brazilian nationals linked to ranching and missionary activity. Traditional cattle ranching, with estancias occupying large portions of the landscape, remains a defining cultural and economic feature of the Chiquitania and the Pantanal borderlands. This blending of Indigenous heritage, missionary legacy, and rural frontier culture gives San Matías a complex human identity shaped by centuries of interaction between people and a demanding but ecologically rich environment.

ANMI San Matías stands out for its combination of vast scale and ecological complexity. Few protected areas in South America span the transition between tropical wetlands, dry forests, and savannas in such a seamless continuum. The Ramsar-recognized wetlands, including Laguna Mandioré and Laguna Cáceres, are among the most pristine freshwater ecosystems in the Bolivian lowlands.

The area also holds exceptional wildlife value, particularly for flagship species such as the jaguar, the giant otter, the hyacinth macaw, the marsh deer, and the maned wolf. The presence of endemic plants, especially cacti and bromeliads of the Cerrado, adds a botanical dimension of global significance. Together with the cultural presence of Chiquitano and Ayoreo communities, San Matías offers an unusually complete portrait of lowland South America's natural and human heritage.

The experience of visiting San Matías varies dramatically with the seasons, which is one of its defining characteristics. The rainy season, from November to March, transforms the landscape: rivers swell, lagoons expand, and vast stretches of savanna become flooded wetlands. This is generally the best period for observing waterbirds and aquatic wildlife, though many dirt roads may become difficult to access.

The dry season, from May to September, produces a very different atmosphere. Wetlands shrink, wildlife concentrates around remaining water sources, and mammals such as jaguars, deer, and peccaries become easier to observe. Forest trails are more accessible, and cooler temperatures make travel more comfortable, though daytime heat can remain intense, especially in the eastern portion of the protected area. July is typically the driest month. Travelers interested in the full ecological rhythm of the Pantanal often consider splitting their visit between seasons to experience both extremes of the landscape.