Environmental context

A unique and threatened environment

The Upper Paranapanema Basin is a landscape of contrasts. 

It contains some of the largest remaining remnants of Brazil’s Atlantic Forest alongside highly degraded agricultural areas affected by erosion, water stress, and biodiversity loss.

Located at the edges of the Atlantic Forest and the Cerrado, the basin supports high biodiversity and plays a critical role in water regulation and landscape connectivity.

Over recent decades agricultural expansion and intensification, and expansion of irrigation have placed growing pressure on soils, rivers, ecosystems, and rural livelihoods.

These overlapping environmental and socio-economic pressures make the basin both high risk and high opportunity.

With targeted restoration and improved land-use management (particularly along waterways) the Upper Paranapanema has the potential to become a model for balancing agricultural production, water security, and nature recovery at a landscape scale.

Current situation

Research insights

Current situation

The total area of the Upper Paranapanema Basin is close to 2.3 million hectares, with a quarter covered by native vegetation.  Native vegetation cover varies between municipalities, ranging from close to 50% in Bom Sucesso de Itararé down to 8.5% in Arandu.

Data sources:

Relatório de Situação dos Recursos Hídricos da UGRHI-14 Alto Paranapanema – Ano base 2022



The Upper Paranapanema Basin is home to a wide range of Atlantic Forest plants and animals. This reflects its position within the Serra de Paranapiacaba forest landscape and the mix of habitats found across the basin, including large areas of forest, river corridors, and transition-zone environments.

Key species groups include:

Large and medium-sized mammals

The region supports forest-dependent mammals typically found in well-preserved Atlantic Forest landscapes. This includes wide-ranging and threatened species such as jaguars, pumas, South American tapirs, bush dogs, southern muriquis, and native deer. These animals rely on large areas of connected habitat and are strong indicators of overall ecosystem health.

Birds

Bird life in the basin is highly diverse, with species associated with intact forests, river edges, and transition habitats. Many Atlantic Forest bird species are sensitive to habitat condition, making them useful indicators of ecosystem health and the success of restoration efforts.

Amphibians and other water-dependent species

Streams, wetlands, and riparian forests support amphibians and other species that depend on clean, well-regulated water. The presence of rare and range-restricted amphibians highlights the importance of headwaters and streamside habitats for conservation.

Plants and vegetation

Native vegetation includes dense montane Atlantic Forest, bamboo-rich forest types, riparian forests along waterways, and smaller areas of high-altitude vegetation. This variety of plant communities creates a diverse set of habitats that supports high species richness across the basin.

Biodiversity in the Upper Paranapanema Basin underpins a set of high-value environmental attributes that are critical at both basin and state scales.

Key environmental values include:

Strategic water sources
The basin contains important headwaters and spring systems that contribute to regional water supply, making forest protection directly relevant to water security.

Landscape connectivity
Large forest blocks, riparian corridors, and remaining forest fragments collectively support ecological connectivity across the landscape, enabling species movement and genetic exchange.

Soil stability and catchment protection
Native vegetation plays a major role in stabilising soils, reducing erosion, and limiting sedimentation in rivers, particularly important in an agriculturally intensive basin.

Ecological resilience
The coexistence of multiple habitat types increases the basin’s ability to absorb and recover from environmental stressors such as drought, floods, and land-use change.

The species and environmental features of the Upper Paranapanema Basin provide a wide range of ecosystem services that support farming, communities, and downstream water users.  The following services have been classified using the Millennium Ecosystem Assessment framework for ecosystem services.

Provisioning services

Provisioning services are tangible products or resources that people can obtain directly from nature including:

• Freshwater supply for households, irrigation, and industry, drawn from rivers, springs, and aquifers maintained by forests and headwaters
• Food production including crops and livestock supported by fertile soils and favorable climate
• Fish and aquatic resources from rivers and reservoirs throughout the basin
• Timber and fuelwood from both native Atlantic Forest remnants and planted forests
• Medicinal plants and genetic resources from the region's rich biodiversity
• Fiber and fodder for livestock and various agricultural uses

Regulating services

Regulating services deliver benefits obtained from the regulation of ecosystem processes:

• Water purification through natural filtration, nutrient uptake by vegetation, and buffering of pollutants before they reach waterways
• Water flow regulation including groundwater recharge, maintenance of river flows during dry periods, and buffering of seasonal variability
• Flood regulation through water retention in forests, wetlands, and soils, reducing peak flows and protecting downstream communities
• Erosion control and sediment retention by vegetation and root systems, reducing damage to rivers, reservoirs, and infrastructure
• Pollination by native insects and other animals, supporting both wild plant reproduction and agricultural productivity
• Pest and disease regulation through natural predators and ecosystem balance, reducing agricultural losses
• Climate regulation at local and regional scales, moderating temperature and moisture extremes
• Carbon sequestration and storage, especially in mature Atlantic Forest vegetation and soils

Cultural and indirect services

Cultural services provide non-material benefits that contribute to human wellbeing and quality of life:

• Recreation and ecotourism opportunities in forests, rivers, and reservoirs, supporting local economies
• Aesthetic and spiritual values derived from natural landscapes, waterfalls, and forest environments
• Scientific research and environmental education, improving understanding and management of natural systems
• Cultural heritage and regional identity linked to forests, rivers, and traditional land use practices
• Sense of place connecting communities to their landscape and history

Supporting services

Supporting services are foundational ecological processes that underpin all other ecosystem services:

• Nutrient cycling through decomposition and biological processes, which underpin long-term land productivity
• Soil formation and maintenance through weathering, organic matter accumulation, and biological activity
• Primary production by plants, converting solar energy into biomass that supports all food webs
• Habitat provision for native species and pollinators, supporting biodiversity and ecosystem balance
• Landscape connectivity allowing species to move and ecosystems to function over time
  

Research insights

Native vegetation in the basin ranges from large, continuous forest areas, such as the Serra de Paranapiacaba ecological continuum, the largest remaining Atlantic Forest block in Brazil, to highly fragmented landscapes dominated by small forest patches. 

Despite their size and isolation, these fragments retain a significant proportion of the region’s original biodiversity, demonstrating their continued ecological value.

Land use, ecosystem condition, and environmental pressures vary markedly across the region, creating a mosaic of conserved and degraded areas with different risks and restoration needs.

This reflects long-term land use change and uneven conservation outcomes across municipalities, resulting in extremes of preservation and degradation within the same basin.

Methods, data and assumptions

Reference publications

Ribeiro, M.C., Metzger, J.P., Martensen, A.C., Ponzoni, F.J., & Hirota, M.M. (2009).
The Brazilian Atlantic Forest: How much is left, and how is the remaining forest distributed?
Biological Conservation

Ribeiro, M.C., Martensen, A.C., Metzger, J.P., Scarano, F.R., & Fortin, M.J. (2011).
The Brazilian Atlantic Forest: A shrinking biodiversity hotspot.
Biodiversity Hotspots: Distribution and Protection of Conservation Priority Areas. Springer

Martensen, A.C., Ribeiro, M.C., Banks-Leite, C., Prado, P.I., & Metzger, J.P. (2012).
Associations of forest cover, fragment area, and connectivity with Neotropical understory bird species richness and abundance
Conservation Biology

The Upper Paranapanema lies at the interface between the Atlantic Forest and the Cerrado, creating a mosaic of landscapes shaped by climate, soils, and hydrology.  This transition zone supports species from multiple biomes which increases biodiversity, but also heightens species sensitivity to habitat loss and fragmentation.

Research shows that species respond differently to habitat loss depending on their position within geographic ranges.  This indicates that conservation and restoration in transition regions can be particularly important for maintaining populations at range edges.

Methods, data and assumptions

Reference publications

Hasui, E. et al. (2024).
Populations across bird species distribution ranges respond differently to habitat loss and fragmentation.
Perspectives in Ecology and Conservation

Permanent Preservation Areas (PPAs) are a central mechanism in Brazilian environmental law for protecting water resources, soils, biodiversity, and ecological connectivity on private land. In Southwestern São Paulo, a large share of these areas—especially along rivers and streams—are currently degraded and out of legal compliance, creating significant environmental liabilities for rural properties.

Approximately 155,000 hectares of riparian PPAs exist in the region, and nearly half are degraded. Large rural properties dominate the landscape and therefore hold most of the total area of PPAs requiring restoration. However, smaller properties show a higher proportion of degradation, meaning they are often less compliant despite having less land overall. This imbalance has important implications for policy design, as compliance costs fall unevenly across landholders.



Restoring PPAs is critical not only for legal compliance but for water security and landscape connectivity. Riparian PPAs link small forest fragments to major forest blocks, including the Serra de Paranapiacaba ecological continuum, and play a key role in maintaining water quality and regulating flows in a highly farmed landscape. Yet restoration costs are substantial, estimated at USD 76–100 million across the study area. Without financial incentives, payments for ecosystem services, or lower-cost restoration approaches (such as agroforestry and natural regeneration), many landholders (particularly smallholders) are unlikely to be able to meet their legal obligations.

Methods, data and assumptions

Reference publications

Ferrari, V. M., Melo, S. R., Oliveira, M. A., & Martensen, A. C. (2021).
Passivo ambiental das Áreas de Proteção Permanentes (APPs) ripárias do Sudoeste Paulista.
Estudos Geográficos

Despite its ecological importance, biodiversity in the basin remains incompletely documented. The rediscovery of the rare amphibian Phrynomedusa appendiculata in Capão Bonito after more than 40 years highlights substantial gaps in species inventories and long-term monitoring.

This finding enabled new ecological, acoustic, morphological, and phylogenetic data to be collected.  It also suggests that additional species of conservation concern may remain undocumented.

UFSCAR has a range of initiatives to document species richness in the region including installing recording devices at various locations and using machine learning to rapidly identify species.

Image source

Methods, data and assumptions

Reference publications

Moraes, L.J.C.L. et al. (2022).
Rediscovery of the rare Phrynomedusa appendiculata.
Zootaxa, 5087

Scientific evidence indicates that climate change is altering rainfall patterns in the Alto Paranapanema Basin, with implications for water resources, agriculture, ecosystems, and infrastructure. Observed and modelled changes include shifts in the timing and amount of rainfall.

These climatic shifts matter because water availability and variability are central to the basin’s socio-ecological systems, influencing crop water demand, erosion risk, species habitats, and hydrological function.

Analysis focused on the Alto Paranapanema Basin finds temporal shifts in rainfall patterns, including a reduction in rainfall during the wet season of up to 40% compared to historical averages. These changes point to a more variable and potentially less predictable rainfall regime, with implications for water storage, agricultural timing, and ecosystem water balance.

Methods, data and assumptions

Reference publications

Hucke, A. T. S., et al. (2024). 

Assessment of climate change impacts on rainfall and streamflow in the Alto Paranapanema Basin, Brazil. 

Journal of Water and Climate Change

Changes in land use and land cover in the Upper Paranapanema Basin, particularly the expansion and intensification of agriculture, have led to a sharp increase in soil erosion, sediment production, and sediment export to water bodies.

Between 1987 and 2017, sediment production more than doubled and sediment export increased substantially, reflecting the conversion of pasturelands to more intensive agricultural systems and the expansion of farming into areas with higher erosion susceptibility.

Modelling results indicate that restoring riparian Permanent Preservation Areas (PPAs) and adopting conservation practices such as terracing and no-tillage can significantly reduce both sediment production and sediment export, especially when these strategies are combined.

Methods, data and assumptions

Reference publications

UFSCAR research