Reforest or perish: ecosystem services provided by riparian vegetation to improve water quality in an urban reservoir (São Paulo, Brazil)

We estimated the economic value of ecosystem services provided by the legally protected vegetation in riparian zones (RPA- riparian protected areas) of watercourses of the Guarapiranga Reservoir watershed (São Paulo, Brazil), considering two scenarios: (i) the value of ecosystem services provided if the RPA recovery complies with the applicable environmental legislation; and (ii) the year 2030, maintaining the urbanization rate and the loss of vegetation cover in the watershed observed between 1986 and 2010. Accomplishing the first scenario demands reforesting 5,917.5 ha of the RPA, which may reduce the annual expenses with chemicals for water treatment and save USD 181.774 per 1000 m3 of treated water. For 2030, we estimated a loss of 6,220 ha of vegetation cover in the RPA (1986 as the initial reference). The loss of ecosystem services provided by RPA would result in an accumulated increase of about USD 318 million in water treatment costs between 2011 and 2030.

Conflitos decorrentes da ocupação do solo nas margens da represa Guarapiranga, no município de Embu Guaçu, em consonância com a legislação ambiental vigente

<p>The Forest Code (Federal Law 12.651/12) defined limits for the occupation and use of soil, creating the Permanent Preservation Areas (PPA), because the occupation and human activities, exercised on the banks of the great water-supply reservoirs, increases constantly, impairing the quality of water, the flora and fauna, phenomenon known as anthropic activity. The Guarapiranga Reservoir is located in the southwest of the Metropolitan Region of São Paulo; covering part of the Cotia, Embu, Itapecerica da Serra, Juquitiba, São Lourenço da Serra, Embu Guaçu and São Paulo municiçpalities. The objective of this study is to observe the situation of the area covered by surroundings of the Guarapiranga Reservoir and its tributary basin, in particular in the Embu Guaçu municipality, as regards the use of water and soil occupation, in line with the Brazilian Forest Code and relevant legislation. They were used geo-processing techniques to define the use of the banks of the reservoir within the Area of Permanent Protection (with 100 meters in rural areas and 30 meters in urban). This delimitation was carried out on Google Earth a program QGIS. This application of geoprocessing technique was accompanied by field work through which it was possible, to analyze the occupation and soil use in the study area. As final result, it was observed that, except special cases, the law determining the use of soil within the Permanent Preservation Areas, is being respected in the municipality of Embu Guaçu.</p>

Composition and distribution of diatom assemblages from core and surface sediments of a water supply reservoir in Southeastern Brazil

Fresh water biodiversity is an increasing concern due to growing human impact. Herein, we report a long-term survey (ca. 90 years) of sedimentary diatoms and the modern flora from surface sediments and their biodiversity changes along a eutrophication gradient. Study was carried out in one of the most important water supply reservoirs (Guarapiranga Reservoir) of São Paulo Metropolitan Region, Brazil. Results are based on 75 core subsamples (subfossil assemblages from core) previously dated by 210Pb and 14 samples from surface sediments (modern assemblages). Overall, 84 taxa were reported, belonging to 30 genera, 71 species and eight non-typical varieties, besides five probable new taxa. Results expanded two new additions for the Brazilian diatom flora (Chamaepinnularia submuscicula and Stauroneis acidoclinata) and 30 infrageneric taxa for the state of São Paulo. 47.6% of total taxa inventoried were accounted exclusively for the subfossil assemblages indicating a significant biodiversity change over time. Access to past oligotrophic conditions and to contemporary mesotrophic regions of the Guarapiranga Reservoir accounted for these new additions representing 25% of the total diatom flora. Decline in the total species number along the trophic state gradient occurred for subfossil and modern assemblages. This pattern was even clearer when considering the changes in species richness over time.Eunotia with 21 taxa was the far most represented genera particularly in the oligotrophic phase. During the transitional period (1947-1974), richness gradually declined. With the onset (in the 1970s) and the major eutrophication period (since ca. 1990) occurred a drastic reduction in richness and the replacement of oligotrophic to eutrophic species. Human management also caused abrupt changes in richness. Marked decline occurred (1933) assotiated with hydrological impacts (water discharge increase) with the initial use of the reservoir as a public water supply. Unlike, sudden increase occurred probably associated with the application of algaecide to control cyanobacterial blooms. Present findings highlight the need for surveying the diatom assemblages in protected environments or in less degraded conditions for biodiversity assessment. Furthermore, reinforce the use of paleolimnological approach as in many cases the only tool to assess biodiversity changes encompassing time scales relevant to human-induced degradation and pre-anthropogenic impacts.

Water quality in four reservoirs of the metropolitan region of São Paulo, Brazil

Aim: This paper describes some limnological variables of four reservoirs with different trophic status (Billings, Guarapiranga, Jundiaí and Paiva Castro) of the Metropolitan Region of São Paulo, Brazil, aiming to characterize the water quality in these reservoirs. Methods Water sampling occurred between October 2011 and September 2012, on subsurface, at the pelagic compartment. Physical and chemical characteristics of water were evaluated, and the Trophic State Index (TSI) was calculated. Multivariate Principal Components Analysis (PCA) was used to ordinate sampling sites and periods in relation to environmental data. Results Two reservoirs were classified as eutrophic (Billings and Guarapiranga), one as mesotrophic (Jundiaí) and one as oligotrophic (Paiva Castro). The highest concentrations of total phosphorus, nitrogen and chlorophyll a were recorded in the eutrophic reservoirs. The lowest values of dissolved oxygen concentration were registered at Guarapiranga reservoir. Residence time in Paiva Castro reservoir was very low (one day); on the other hand, the highest value was recorded in Billings reservoir: 428 days.