In the last 40 years, Paraguay has lost most of its natural forest area, becoming one of the countries with the highest rate of deforestation in the world. Rapid expansion of agricultural land, cattle ranching, and illegal logging have transformed the last remnants of forest into isolated patches, threatening their connectivity and the biodiversity within them. In response to these events, the Paraguayan government has implemented numerous environmental programs and regulations to repair the damage done in the past.
The Paraguayan Chaco covers the western part of the country and occupies 60 % of its territory. The area is characterized by a mosaic of vegetation types, composed of forests and dry woodlands, combined with riparian vegetation, savannas and grasslands. It is also one of the last wilderness areas in the tropics. The Paraguayan Chaco has become an important center of economic development in recent years. Cattle ranching has increased in this area and has become one of the economic backbones of the country. Artificial pastures have continued to displace natural vegetation, leading to increasing fragmentation of the forest. This development has come at the expense of natural resources and has severely impacted wildlife habitat in the region.
Visualization of 34 years of forest cover loss in the Paraguayan Chaco.
Deforestation in and near by protected areas and indigenous communities
The areal maps show that forest loss within the boundaries of protected areas represents only 1% (550 km2) of the total area deforested in the Paraguayan Chaco between 2000 and 2020. However, there are individual protected forest areas where up to 25% of the forest was cleared between 2000 and 2020. In addition, the loss of forest area in most protected areas is increasing dramatically outside the boundaries of the protected areas, with rates ranging from 8% to 60%. For example, in the Palmar Quemado, Yaguarete Pora, Cerro Chovoreca, and Defensores del Chaco protected areas, little forest is being cleared within their boundaries. However, forest loss increases dramatically in the 5 km buffer zone, where nearly 67% (166 km2), 9% (32 km2), 12% (55 km2), and 17% (605 km2) of the forest has been cleared, respectively.
Using a set of metrics for landscape analysis, namely core area, forest patch size, total edge, edge density, and proximity, forest fragmentation was assessed in 2000, 2010, and 2020. The above-mentioned forest loss is associated with a significant decrease in core area and a doubling in the number of forest patches (12,010 in 2000 to 23,228 in 2020). The average size of a forest plot decreased from 14 km2 in 2000 to 5 km2 in 2020, and the total core area decreased by more than 60%. While 64% of the total forest area was in the core zone in 2000, this percentage decreased to 37% in 2020. In addition, an increasing complexity of forest land form was observed. The total boundary of all forest land increased from 310,300 km in 2000 to 433,200 km in 2020, while the length of the boundary of an average forest patch decreased at the same time. In addition, a neighborhood assessment was conducted to identify forest patches in terms of their embeddedness in the fragmented forest area. Proximity between patches can be used to identify potential biological corridors that allow for species movement and dispersal. During the study period, this index also decreased. It is notable that there is a clear trend in all of the metrics. Today, only the northern part of the Paraguayan Chaco can be considered a contiguous forest. Nevertheless, even in the north, both proximity and the core area index have declined sharply. Patches with a large proportion of core area have disappeared over the 20 years of the study, leaving only one region with a large core area index in the north (72-80%), the Defensores del Chaco Nature Reserve. The surrounding areas have much lower percentages of core area, making the protected area an isolated island.
Information on vegetation structure is key information in determining wildlife habitat quality and terrestrial carbon storage. Thus, large-scale maps of tree canopy height and vegetation density are particularly important in an era of global climate change. Novel spaceborne LiDAR samples from the Global Ecosystem Dynamics Investigation (GEDI) sensor provide attributes of vegetation structure as footprint data for all temperate and tropical forests. Modeling of GEDI samples based on high-resolution mapping missions such as Sentinel-1 and -2 provides continuous vegetation structure information. We implemented a random forest regression model to extrapolate GEDI samples based on temporal-spectral features from Sentinel-1 and -2 to 10-m resolution data that include canopy height, total canopy cover, plant-area index, and foliage-height-diversity index.