Forest restoration can increase the Rio Doce watershed resilience

Pires, A. P. F., et al., 2017. Perspectives in Ecology and Conservation

Original research (primary data)
View External Publication Link

Abstract

Rio Doce watershed has centuries of land degradation and it was the main victim of the worst environmental disaster in Brazil’s history. This process of deforestation and soil erosion could be significantly mitigated if compliance to the new Brazilian Native Vegetation Protection Law (NVPL) would be ensured. Here, we show how the percentage of forest kept in areas of permanent preservation (APP) required by the NVPL drives the overall resilience and resistance of the entire Rio Doce watershed and how it contributes to the national restoration commitments. We used water quality as a proxy for watershed resilience and resistance and we found that compliance to NVPL would require restoration of about 716 thousand hectares of riverine forest across the watershed. We found that increased forested areas improved watershed resistance and resilience during the rainy and dry seasons, respectively. Our estimates suggest that the implementation of the NVPL could improve water quality, in addition to removing 14 Gt CO2 yr?1 ha?1 from the atmosphere. At this scale, the forest restoration effort would represent 6% of Brazil’s restoration commitment. Financial feasibility of such a restoration enterprise is also achievable; at the highest possible estimate, it would compromise about 59% of the total fund proposed by the mining companies responsible for the accident. Given the low socioeconomic indicators of this basin, intervention should be designed so as to improve local livelihoods and, therefore, contribute to local adaptation and sustainable development.

Case studies

Basic information

  • Case ID: INT-082-1
  • Intervention type: Combination
  • Intervention description:

    Native Vegetation Protection Law (the so-called New Forest Code; NVPL hereafter) that establishes the proportion of land within rural properties that must be maintained under protection or should be restored with native vegetation NVLP establishes the full protection of riparian vegetation of rivers, springs and other water sources in rural properties as areas of permanent preservation, hereafter APPs. The NVLP is not yet fully implemented. They first looked at the % of vegetation cover and % of native vegetation in the APPs upstream each sampling point. They then also assessed the potential impacts (and costs) of implementing the NVLP (protection and restoration) over the entire watershed The increase in the watershed resilience and resistance were estimated based on the equation that describes the correlation between the WQI slope values and 1/CV values and the percentage native vegetation in APPs, respectively.

  • Landscape/sea scape ecosystem management: Yes
  • Climate change impacts Effect of Nbs on CCI Effect measures
    Reduced water quality  Positive the water quality index (WQI), as suggested by the US – National SanitationFoundation (ANA, 2015a). Water quality index integrates ninelimnologic variables (i.e. thermotolerant coliforms, dissolvedoxygen, turbidity, nitrates, total phosphorus, total suspendedsolids, biological oxygen demand, temperature variation and pH)to determine a single value for water qualityWe determined watershed resilienceand resistance by verifying the temporal behavior of WQI for eachsampling point (Box 1).Watershed resilience was defined as the ability of the systemto return the WQI value to a natural condition, where the hypothetical WQI value is maximum (100)Watershed resistance was defined asthe ability to keep the WQI close to its mean temporal behavior, determined as the coefficient of variation (CV).
  • Approach implemented in the field: Yes
  • Specific location:

    Rio Doce river runs 888 km and its basin area is about 84 000 km2, of which 86% are in the state of Minas Gerais and 14% in the state of Espírito Santo, in southeast Brazil.

  • Country: Brazil
  • Habitat/Biome type: Streams, rivers, riparian |
  • Issue specific term: Ecosystem-based adaptation

Evidence

  • Notes on intervention effectivness: study looks at how changes in the percentage native vegetation in the APPs drove changes in water quality magnitude (i.e. average WQI), resilience (i.e. slope value of the correlation between WQI and time), and resistance (i.e. WQI coefficient of variation) along the Rio Doce watershed. They then predicted watershedwide impact of fully implemented NVLP plan. However, the percentage of native riparian vegetation increased watershed resilience during the dry season.but not during wet season... areas with at least 50% of upstream native vegetation increased WQI than areas that didn’t with the effect magnified during the dry seasonative vegetation cover reduced variability in WQI (higher resistence) during rainy season if restoring entire watershed, would be effective to improve water qualityOur analysis demonstrated that increases in the percentage of riparian vegetation cover decreased the variability in water quality during the rainy season which will help deal with climate change (extreme rainfall events)During the rainy season, the surfacedrainage carries out several compounds to water bodies, making the riparian vegetation extremely important in buffering such effect (Klapprath and Johnston, 2000). On the other hand, duringthe dry season, restored riparian vegetation enhanced watershed resilience, as shown by the slight increase in water quality over the last decade (see positive slope values, Fig. 2).
  • Is the assessment original?: Yes
  • Broadtype of intervention considered: Not applicable
  • Compare effectivness?: No
  • Compared to the non-NBS approach: Not applicable
  • Report greenhouse gas mitigation?: Yes
  • Impacts on GHG: Positive
  • Assess outcomes of the intervention on natural ecosystems: No
  • Impacts for the ecosystem: Not reported
  • Ecosystem measures:
  • Assess outcomes of the intervention on people: No
  • Impacts for people: Not reported
  • People measures:
  • Considers economic costs: Yes
  • Economic appraisal conducted: No
  • Economic appraisal described:
  • Economic costs of alternative considered: No
  • Compared to an alternative: Not reported

Evaluation methodology

  • Type of data: Quantitative
  • Is it experimental: No
  • Experimental evalution done: Not applicable
  • Non-experimental evalution done: Empirical case study
  • Study is systematic: