South American Pampas loses one fifth of its grassland vegetation between 1985 and 2021
Native vegetation now covers less than half of the biome
The analysis of satellite images taken between 1985 and 2021 by a collaborative network of experts from Argentina, Brazil and Uruguay, under the coordination of MapBiomas, shows that the South American Pampas lost 20% of its grassland vegetation in the period, including 8.7 million hectares of native grasslands and 260 thousand hectares of forests. The data on the transformations of this biome, which covers more than one million square kilometers between Brazil, Argentina and Uruguay, occupying 6.1% of South America, was released today (12/14) by the researchers. The new collection of annual land cover and land use maps is the most complete ever prepared for the biome. The previous collection, released last year, was limited to the 2000-2019 period.
Native vegetation now covers less than half of the Pampa (48.4%). Most of it corresponds to grassland vegetation (32%), traditionally used for cattle raising. This is a unique case in which livestock production and biodiversity conservation generally integrate productive systems with notable environmental sustainability. Despite this, almost half (47.2%) of the region has been replaced by agriculture, planted pastures or forest. The areas of agriculture and forestry increased 15.3% in the period, which means about 6.8 million hectares. In area, the advance of forestry was smaller: 2.2 million hectares. But this represented an increase of 363%. The native grassland vegetation, which is the natural vocation of the biome, fell from 44 million hectares in 1985 to 35.3 million hectares in 2021.
"Several scientific studies indicate that the South American Pampas is one of the least protected and most threatened biomes on the continent, precisely because of the high rates of transformation in land cover and use and the low levels of conservation of its natural ecosystems," explains Eduardo Vélez, MapBiomas Pampa team. Although in 1985, when the mapping period begins, at least half of it was already occupied by human activities, such as agriculture, livestock, forestry and urban areas, since we are talking about a densely occupied region that is home to large cities such as Buenos Aires and Montevideo, the transformations in the last 37 years have drastically changed the landscape. The consequences of this are bad for biodiversity and ecosystem services, in addition to compromising the regional potential to produce meat in a sustainable way, at scale, from the typical grassland vegetation of the biome.
Brazil, greatest proportional loss
The country that had the greatest proportional loss of grassland vegetation was Brazil, with 3.2 million hectares - equivalent to 65 times the area of the municipality of Porto Alegre (RS). This is a loss of 34% of the area existing in 1985 in just 37 years. The main vector of this change is the expansion of agricultural areas for soybean planting. The agricultural use of the soil increased 2.6 million hectares between 1985 and 2021. Forestry, in turn, expanded its territory by more than 700,000 hectares in this period - an increase of 1,640%. In 1985, the total area occupied by fields was 9.4 million hectares, and rose to 62.2 million hectares in 2021.
Argentina, largest absolute loss
In absolute terms, however, the greatest loss of grassland vegetation was in Argentina: 3.5 million hectares - the same as 173 times the city of Buenos Aires. This was a loss of 16% of the area in 37 years. In 1985, there were 22.6 million hectares; in 2021, 19.1 million. Just as in Brazil, the main vector was the expansion of agricultural areas and pastures with exotic species. Agricultural land use increased by 1 million hectares. Forestry, in turn, increased more than 340,000 hectares between 1985 and 2021.
Uruguay, forestry advance
In Uruguay, the loss of fields was also considerable: 2 million hectares, or 38 times the department of Montevideo. This was a 17% drop from the total area in 1985, a combined effect of the advance of agriculture and forestry. Agricultural land use alone increased by 30% between 1985 and 2021, from 3.3 million hectares to 4.3 million hectares. But the big change, in percentage terms, was in forestry, which expanded its area by 625%, from 180,000 hectares in 1985 to 1.3 million hectares in 2021.
- The South American Pampas occupies 6.1% (108.9 million hectares) of South America;
- 66% of the mapped area is in Argentina (71.7 million hectares), 18% in Brazil (19.4 million hectares), and 16% in Uruguay (17.8 million hectares);
- The net loss of grassland vegetation between 1985 and 2021 was 8.8 million hectares;
- The combined area of agriculture and planted pasture grew by 10.6%, from 44 million hectares to 48.6 million hectares; and
- The area of forestry (the planting of exotic trees) increased from 600,000 hectares to 2.8 million hectares (363% increase)
About the Pampa
The South American Pampas encompass the southern half of Rio Grande do Sul, all of Uruguay, and part of Argentina, south of the La Plata River. It is a region with very old human occupation and is home to three large metropolises (Buenos Aires, Montevideo and Porto Alegre).
The biodiversity of the Pampas is characterized by the predominance of native herbaceous vegetation, called campestre vegetation, and forests, although present, naturally occupy a smaller proportion. The region's climate varies from subtropical to temperate, with pronounced thermal seasonality (cold winters and hot summers) and no dry season (rain occurs every month of the year).
Because of the natural supply of forage resources from the abundant grassland vegetation, beef cattle production was the characteristic economic activity of the region in the first centuries of European colonization, with a strong influence on the customs and regional culture. However, since the 20th century, the biome has undergone profound transformations in land use, especially due to the advance of grain agriculture and, more recently, forestry. As a result, its ecosystems are among the least protected and most threatened on the continent.
About MapBiomas Pampa Sul-Americano Collection 2
With a resolution of 30 by 30 meters and 8 classes in the legend, Collection 2 of MapBiomas Pampa Sul-Americano (1985-2021) covers 108.9 million hectares of the biome that occupies 6.1% of South America. The platform can be accessed at pampa.mapbiomas.org. The MapBiomas collections are under continuous development and improvement. The researchers of the South American Pampa, who recently finished the new expanded and updated collection, are already working on improvements and new features for new versions.
About MapBiomas Pampa Trinacional
MapBiomas Pampa Trinacional https://pampa.mapbiomas.org/ is an initiative involving a collaborative network of experts from Argentina (Instituto Nacional de Tecnología Agropecuaria-INTA, Universidad Nacional de San Luis, Universidad de Buenos Aires, and the NGO Fundación Vida Silvestre Argentina), Brazil (Federal University of Rio Grande do Sul and GeoKarten) and Uruguay (Faculty of Agronomy and Faculty of Sciences of the Universidad de la República, Instituto Nacional de Investigación Agropecuaria-INIA, and Ministry of Environment). The project uses Landsat satellite images (30 x 30 meters resolution) and cloud computing through the Google Earth Engine (GEE) platform to produce annual land cover and land use maps with high technology and low cost. The initiative is part of the MapBiomas Network, started in 2015 with MapBiomas Brasil (mapbiomas.org).