Identifying opportunities for local assisted expansion of coastal upland vegetation in an urban estuary

Abstract

Resilience planning requires an understanding of the potential impact of accelerated sea level rise on the narrow coastal habitats between the sea and the built environment in urban estuaries. Preliminary work suggests that facilitating expansion of coastal upland vegetation (grasslands and maritime shrubland/successional maritime forest) may improve resilience. We created a GIS model for Jamaica Bay, New York to identify areas of inland salt marsh migration induced by sea level rise and map potential locations for expansion of coastal upland vegetation through plantings of local provenance given land use, soil type, and adjacency to predicted future salt marshes. We predicted that regularly flooded salt marshes (low marsh) will comprise the large majority of salt marsh area (89% up from 68% currently) in the coming century due to daily tides covering areas currently categorized as irregularly flooded salt marsh (high marsh), brackish marsh and coastal upland vegetation. Considering land use, 16% of the area suitable for coastal upland vegetation within the coastal buffer zone could be considered possible sites for local assisted coastal upland vegetation expansion with about a fifth of those areas adjacent to predicted new sea level rise induced inland salt marsh areas. Parks and recreational facilities (43%) and open space (32%) were the dominant land uses available for local assisted coastal upland vegetation expansion adjacent to predicted new sea level rise induced inland salt marsh areas. Potential sites for local assisted coastal upland vegetation expansion were considerably more numerous on sandy soils than on loamy sand soils. Maintained lawn and shrubs and the borders of roads and railroads provided available space in areas disjunct from the predicted new salt marsh areas. Our study of opportunities for local assisted expansion of coastal upland vegetation fills a gap within existing models and informs land managers of predicted future inland salt marsh migration locations, regions of existing vegetation to support, and areas where restoration plantings may help sustain coastal upland vegetative communities and their many ecological services.