The value of wetlands for water quality improvement: an example from the St. Johns River watershed, Florida

Wetlands provide many valuable ecosystem functions such as sediment and nutrient retention, high biological productivity and biodiversity, flood control, and opportunities to recreate. Despite their importance, estimating the value of wetlands is difficult as the worth of these functions and services is not easily quantified. The overall objective of this study was to estimate the value of freshwater wetlands in the Saint Johns River (SJR) watershed, Florida based on their ability to remove nutrients, namely nitrogen (N) and phosphorus (P). We used a combination of literature review, geospatial analysis of land cover, and regression analysis to determine the total wetland area in the SJR watershed and the rates of nitrogen and phosphorus burial in the wetlands. We then estimated the economic value of these wetlands based on the replacement cost of nutrient removal by wastewater treatment plants. Nitrogen burial rates ranged from 27 g/m2/year to a background rate of 6.56 g/m2/year, and phosphorus burial rates range from 1.31 g/m2/year to a background of 0.11 g/m2/year. Using these rates, we calculate wetlands of the SJR catchment remove 79,873 MT of nitrogen annually just from burial in the soil, with a replacement cost of between $240 million to$150 billion per year. The amount of phosphorus buried yearly is more than 2400 MT with an annual replacement cost of $17 to$497 million. Though they are based on limited data and include a variety of watershed-scale research limitations, these findings highlight the significant potential value of conserving functional wetlands based solely on their nutrient retention functions. If we were to consider the benefits associated with other wetland functions such as flood control, biological productivity, and biodiversity in addition to their ability to retain nutrients, the value of the SJR wetlands would be even greater

Soil recovery across a chronosequence of restored wetlands in the Florida Everglades

The restoration project in the Hole-in-the-Donut of Everglades National Park in Florida, USA is to reestablish native wetlands by complete removal of the invasive plants and the associated soil. However, there is little information available about changes in properties of the newly formed Marl soils in restored wetlands. In this study, we measured soil physicochemical properties, soil enzymatic activities, and stable isotopes of carbon (δ(13)C) in plants and soil organic carbon (SOC) in an undisturbed natural wetland (UNW) and three wetlands restored respectively in 1989, 1996 and 1999 (WR89, WR96 and WR99). The older restored wetlands (WR89 and WR96) are characterized by greater SOC and mineral nitrogen. The values of soil dehydrogenase and phosphatase activities in the four wetlands follow the order: UNW > WR89 > WR96 > WR99, and are consistent with changes in vegetation coverage. The principal component analysis shows that dehydrogenase and phosphatase activities are the vital variables contributing to the soil of UNW. The similar δ(13)C values of SOC and plants in the restored wetlands suggest the formation of SOC during restoration is mainly derived from the associated plants. These results indicate that the newly restored soils develop toward the soil in the UNW with time since restoration

Value Creation in Teacher Learning Networks

Research shows that teacher professional learning is most effective when it is characterised by active engagement of teachers, a direct connection to their daily practice, and high levels of collaboration. Increasingly, networked professional learning is promoted to enable teachers to make better use of the potential of their social context and improve the quality of their learning. This chapter explores value creation in teacher learning networks and investigates how value creation is affected by contextual factors. The study was conducted in two projects that aimed to promote and facilitate teachers’ networked professional learning. The findings showed little difference in teachers’ networked learning activity itself, but substantial differences were found in leadership commitment, time, and opportunity for networked learning and voluntary network participation. Overall, the study shows how creating connections between teachers may lead them to redefine their idea of what learning could be like and reframe the value of their peers for learning. Interestingly, the combination of committed leadership and mandatory network involvement appeared to have helped teachers to have positive networked professional learning experiences