On 8 April 2011, a report on the state of conservation of the property was submitted by the State Party. From 22 to 27 January 2011, a joint World Heritage Centre/IUCN monitoring mission visited the property following its inscription on the List of World Heritage in Danger at the request of the State Party (Decision 34 COM 7B.29). The mission report is available online at the following web address: http:/whc.unesco.org/en/sessions/35COM.
a) Alterations to the Hydrological Regime (volume, distribution of inflows)
The State Party notes that water management changes in the upstream Everglades over the last century eliminated much of the natural sheetflow through the Everglades, which over time caused the peat soils to oxidize and the ridge and slough landscape to flatten, as open-water slough communities were replaced by dense sawgrass. The State Party also notes that these habitat changes resulted in a significant decline in the property’s aquatic productivity and a loss in overall biodiversity, causing a reduction in primary food sources, which led to a decline in wading bird populations of 70 to 90% compared to pre-drainage estimates. The State Party further notes that prolonged flooding in the marl prairies of Western Shark River Slough, and the associated habitat change towards wet prairie vegetation, has caused a marked decline in the nesting success of the ground-nesting, critically endangered Cape Sable Seaside Sparrow. According to information received by the mission, the population of this sparrow has declined by 90% in comparison to pre-drainage estimates.
The State Party notes that a number of the corrective measures adopted by the World Heritage Committee at its 30th session (Vilnius, 2006) address the issue of the altered hydrological regime, through raising and bridging the Tamiami Trail, adding new conveyance and seepage management features, and revising water management operations to increase water volumes and improve flow distributions to the property. These corrective measures are part of the Modified Water Deliveries and C-111 South Dade Projects. The State Party reports that progress in the implementation of both these projects has been slow, and that restoration efforts to date have yielded only minimal improvements in water volumes or flow distributions relative to what is needed to achieve the Desired state of conservation.
The mission concluded that the restoration of the property is dependent not only on the improved hydrological flows anticipated in the current Modified Water Deliveries and C-111 initiatives, but also on other projects (current and future) which make up Comprehensive Everglades Restoration Plan (CERP) and non-CERP activities and which focus on the need to integrate new scientific information and catchment-wide hydrological objectives. It is essential that the State Party further progresses the modifications on the Tamiami Trail to include extending the bridging to a further 5.5 miles, in line with the recommendation of the Final Feasibility Study and Environmental Impact Statement for the Tamiami Trail Next Steps Project, together with additional road raising and other associated infrastructure changes to reduce groundwater seepage losses from the property.
b) Adjacent Urban and Agricultural Growth (flood protection impact)
The State Party reports that the expansion of urban and agricultural development into the eastern marl prairies caused vegetation communities in the eastern marl prairies to slowly shift to more drought tolerant and terrestrial species, and resulted a major loss of productivity and biological diversity of aquatic animal communities. The State Party notes that this once important wading bird foraging area lost much of its ecological value, and the historic rookeries in the southern estuaries began to disappear.
The State Party notes that the completion of the seepage management features from the 8.5 Square-Mile Area to the C-111 south detention area to reduce groundwater losses around the eastern boundary of the property has been partially completed. It also notes that the C-111 northern detention area, which would allow excess flows from the 8.5 Square-Mile Area to pass southward, as well as fill the current gap in the seepage management features in the upper portion of Taylor Slough, is currently in development and expected to be completed by 2017. The State Party further notes that tests are underway to identify appropriate additional seepage management features to reduce groundwater losses from Northeast Shark River Slough.
The mission concluded that it is crucial to strengthen cooperation among all partners involved in the restoration projects through adoption of a common vision which includes conservation of the Outstanding Universal Value (OUV) of the property as a consistent high priority. The mission further concluded that it is essential to ensure that the importance of an entire catchment scale approach and water planning and management in South Florida is fully recognized across all relevant agencies and stakeholders and that decisions far upstream may have significant impacts within the property.
c) Increased nutrient pollution from upstream agricultural activities
The State Party notes that the Everglades have a distinct north-to-south gradient of nutrients and pollutants from the degraded upstream agricultural and urban areas to the relatively un-impacted park. The mission notes that the Central & Southern Florida (C&SF) Project’s canal system acts as a conduit for nutrient transport, and stormwater runoff from the Everglades Agricultural Area (EAA) has significantly increased phosphorus concentrations in the downstream Water Conservation Areas and the Park. The State Party reports that more than 16,200 hectares of Everglades wetlands, primarily north of the property, show signs of significant eutrophication, and these impacted areas are still increasing in size. It notes that the progressive eutrophic impacts include altered periphyton species composition and a complete loss of algal communities, substantially reduced water column dissolved oxygen, increased phosphorus content in the macrophytes and soil, conversion of the prairie, sawgrass, and slough mosaic to dense stands of cattail, reduced fish and invertebrate productivity, and a loss of wading bird foraging habitat.
The State Party notes that approximately 4,900 ha of new Stormwater Treatment Areas (STA) are currently under construction and expected to be operational by 2013. It also notes that other STAs will be expanded and 12,950 ha worth of flow equalization basins constructed by 2014 to 2018. It expects that the expansion of the Stormwater Treatment Area 1 West (STA-1W) could bring approximately 8,712 million cubic feet (mcft) of new water into the Water Conservation Areas and the property.
The mission concludes that it is necessary to resolve uncertainties upstream of the property arising from the legal actions linked in particular to water quality. It considers that it is further essential to address the delays in the implementation of the Modified Water Deliveries (MWD), C-111 and CERP projects, and related water quality initiatives which will result in continued degradation of the property and likely reduce the resilience of the Everglades ecosystem in the face of climate change.
d) Protection and management of Florida Bay
The State Party reports that reduced fresh water inflows to Florida Bay have resulted in increased salinity, especially upstream of the nearshore embayments of central Florida Bay and downstream of the Taylor Slough wetlands. It notes that overall estuarine productivity that is needed for successful reproduction of both estuarine fish communities and their associated wading bird and marine shorebird communities has been significantly reduced, and that the high salinities have contributed to seagrass die-off, recurring algal blooms and increased turbidity. The State Party notes that the ongoing implementation of the C-111 South Dade project and the C-111 Spreader Canal Phase 1 project is expected to create a nearly continuous groundwater ridge along the eastern border of Taylor Slough, to retain water within this watershed and redirect freshwater flows into central Florida Bay. It also notes that plans for substantially increasing flows into Northeast Shark River Slough will ultimately be needed to restore freshwater flows into Florida Bay and reduce bay-wide salinity.
The mission was informed that Florida Bay Florida Keys Feasibility Study (FBFKFS) has not made significant progress since its authorization. The South Florida Natural Resources Center (SFNRC), which contributed significantly to the FBFKFS, continues to develop the physical and ecological models that address the issue of how inflows affect the salinity regime of Florida Bay and the potential biological responses. The results of this work are intended to provide tools for assessment of proposed changes in water management as well as establish specific targets for restoration of inflows that will significantly benefit the Bay ecosystem. This work is conducted in coordination with the multidisciplinary and multi-agency efforts toward the common goal of providing science-based recommendations on Everglades restoration. A report is anticipated end 2011.
e) Effects from climate change and sea level rise
The mission notes that successful restoration of historic fresh water flows through Shark River and Taylor Sloughs is likely to improve ecosystem resilience and enhance capacity to adapt to climate change and sea level rise. It also notes that improved fresh water flows would help hold back salt water intrusion and avoid the very rapid environmental change which reduces the ability of species to move or adapt. The World Heritage Centre and IUCN note that movement of certain habitats such as mangroves may be inevitable but this does not in itself necessarily threaten OUV. The mission considers that there is currently insufficient evidence that climate change and sea level rise will pose an immediate or equivalent degree of threat as those associated with the alterations in freshwater quantity and quality entering the property.
f) Invasive species
The mission found evidence of significant increases in invasive species of both flora and fauna and considers that these increases could well be a threat to the property’s OUV. The mission concludes that it is necessary to undertake an assessment of the effects of invasive species (plants and animals) on the OUV of the property.
g) Desired state of conservation for removal of the property from the List of World Heritage in Danger
As requested by Decision 34 COM 7B.29, the mission assisted the State Party with the development of a Desired state of conservation for removal of the property from the List of World Heritage in Danger. Fourteen different indicators are proposed to monitor the integrity and ecological rehabilitation, as well as management effectiveness. Proposed integrity indicators include the magnitude and direction of sheetflow, timing and distribution of surface water depths (hydro-pattern) and the concentration of total phosphorus in freshwater Everglades. Proposed ecological indicators include concentrations and distribution of nutrients and salinity in Southern Coastal ecosystems, species abundance and distribution of periphyton and freshwater faunal assemblages, abundance and distribution of wading birds; American Alligator; American Crocodile, submerged aquatic vegetation in Southern coastal ecosystems (notably seagrasses) as well as the nearshore faunal community (notably spotted seatrout and pink shrimp). Proposed management effectiveness indicators include catchment-wide support of a common vision for the conservation of the property’s OUV, and delivery of necessary financial resources. A detailed description is available in the mission report. The report submitted by the State Party further refines these indicators and provides measurable targets for the integrity indicators. No measurable target or quantification is provided for the ecological indicators. The World Heritage Centre and IUCN consider that measurable targets or quantification should be developed for all indicators that make up the Desired state of conservation for removal of the property from the List of World Heritage in Danger.
