Ecological Restoration of a Brackish Marsh at Parcel 11, Estate Carolina, St. John

Transcription

1 Ecological Restoration of a Brackish Marsh at Parcel 11, Estate Carolina, St. John Gary Ray, Ph.D. Virgin Forest Restorations For Coral Bay Community Council

2 Aerial of Parcel 11 Brackish Marsh Ecological Restoration Area and Environs

3 Ecological value of wetlands Flood control Groundwater replenishment Shoreline stabilisation & storm protection Sediment and nutrient protection Water purification Reservoirs of biodiversity Wetland products Cultural values Recreation and tourism Climate change mitigation and adaptation

4 Human alteration to the wetland Pre-human contact, the site may have been a landward extension of the fringe mangrove along the immediate coastline Broad scale cultivation (center of sugar production for St. John) during plantation era altered the hydrologic (water flow) conditions Recent road building and storm drainage modifications resulted in accumulation of terrestrial sediment along the perimeter

5 Ecological Restoration Defined The scientific study of renewing degraded, damaged, or destroyed ecosystems by active human intervention over short time scales ; it has a broad scope, and consists of the following strategies: Reintroduction of native species Removal of exotic species Erosion control Hydrologic repair Reforestation

6 Main Goals of Ecological Restoration To facilitate biological recovery of natural communities by focusing on re-introduction of a natural community s most important natural species components and basic physical attributes, thus recovering ecosystem services. Restoration ecology may use historical or prehuman conditions as a guidepost for setting compositional structure of an ecosystem.

7 Sedge community at center of brackish marsh, Parcel 11, Est. Carolina, St. John We define the flooded area as a Brackish Marsh Dominant plants: Cyperus ligularis, Cyperus elegans, & Cyperus planifolius.

8 Coconut grove at southern section of the restoration zone Coconuts are sandy shoreline trees from the Pacific. They tolerate salty soils wherever their root systems can penetrate deeply, but thrive in the best drained soils.

9 Exotic Grazers: large mammals can thoroughly alter natural wetland communities

10 Free-roaming livestock bring weed seeds from outside the site, and stress native species on-site

11 Mexican coral vine is a noxious weed of highly disturbed, open sites on St. John Exotic Plants: Coral vine (Antigonon leptopus)

12 Exotic Species: Rain tree (Samanea saman) This ornamental shade tree from India is prominent near the King s Hill Rd. margin of the property.

13 Coconut palms (Cocos nucifera) are of Pacific origin. It is not a wetland species. It would not be restored to any site on St. John as an ecological restoration focus. We leave the grove intact as a cultural element on the perimeter of the ecological restoration.

14 Exotic Species: Soursop (Annona muricata) was likely introduced from South America, but it is well adapted to local conditions, and a favorite edible fruit.

15 Native Species: Flatleaf flatsedge (Cyperus ligularis) This sedge is a co-dominant species in the wettest portion of the brackish marsh

16 Swamp flatsedge (Cyperus planifolius) Less abundant and somewhat shorter in height than flatleaf flatsedge, but more attractive as an ornamental species.

17 Cyperus elegans This sedge grows low to the ground in soils frequently flooded; it is abundant in the brackish marsh.

18 Fenceline along west boundary of the wetland restoration site. Land to the right will be managed by the VI Dept of Agriculture.

19 The natural sedge community is thriving. It will be enriched in areas denuded or compromised by grazing. The coconut grove on the site s SW corner will remain. Other native woodland components will be enhanced.

20 Aerial of Parcel 11 Brackish Marsh Ecological Restoration Area and Environs

21 Map of Parcel 11, Est. Carolina, St. John Existing Plant Communities

22 Map of Ecological Restoration Site Exotics Removal and Planting Zones

23 Project is heavy on exotics removal; light on native species enrichment

24 Overview of Project Implementation: Coral Bay Parcel 11 Wetland Restoration