Pagamentos por serviços ecossistêmicos visando à manutenção dos recursos hídricos
Abstract
Changes in land use-land cover by human activities affect hydrological processes and the
supply of water ecosystem services. Forests are positively associated with water quality and
Brazilian legislation through the Native Vegetation Protection Law (NVPL) (Law no
.
12.651/2012) established command and control instruments, such as Permanent Preservation
Areas (PPA) and Legal Reserve (LR) to avoid deforestation. However, the areas established by
the NVPL are insufficient to avoid diffuse pollution and the deterioration of water bodies. In
this context, Payments for Ecosystem Services (PES), an economic incentive instrument, can
be an alternative tool for protecting water resources. Therefore, our main objective is to
understand how PES programs can be an instrument to enhance the supply of water
environmental services in agricultural watersheds. The study was developed in the Sarapuí river
basin, SP, using 2019 orbital images from the Sentinel-2ª satellite, with a spatial resolution of
10m, to identify soil use and cover. We carried out water collections every two months in 6
watersheds during 2022 and compared the water quality parameters with collections in 2013/14.
We use statistical tests to identify the relationship between land use-land cover with parameters
at the scale of the watersheds and PPAs and changes in land use-land cover. We compared the
protection of priority areas for conservation to maintain water resources with areas legally
protected by the LPVN. In addition to the legal protection scenario (30m PPA), a 100m PPA
scenario was simulated to compare the protection of priority areas by the legal scenario and a
more conservative scenario. Finally, we used data available from the “Biota-Fapesp Florestal
Code” project to identify the deficit of native vegetation on rural properties and also to
characterize properties according to size. We identified that all anthropogenic uses in
watersheds negatively impact water quality (pasture, agriculture, and urban) and that forest
cover is the most positively associated with water quality. Most of the variation in water quality
was explained at the watershed scale, which emphasizes the importance of adopting
conservation strategies in the watershed as a whole and not only in PPAs. Furthermore, almost
70% of the highest priority areas for PES are outside the limits of PPAs, and there are few
deficits in LR and PPAs, which demonstrates that there are no additional conservation
incentives on the part of the NPVL. A 100m PPA would increase the protection of these areas
by 150%. Therefore, PPAs can be an instrument to finance the conservation and forest
restoration of priority areas, especially those not included in the LPVN, to expand the adoption
of better agricultural practices and basic sanitation to minimize the impacts of anthropogenic
uses on water quality.
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