Spatial pattern formation of coastal vegetation in response to external gradients and positive feedbacks affecting soil porewater salinity: a model study

• Published in: Landscape ecology Vol. 27; no. 1; pp. 109 - 119
• Main Authors: Jiang, Jiang, DeAngelis, Donald L., Smith, Thomas J., Teh, Su Yean, Koh, Hock-Lye
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 2012; Springer; Springer Nature B.V
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Applied ecology; Biological and medical sciences; Biomedical and Life Sciences; Boundaries; Brackish water ecosystems; Coasts; Dry season; Ecological adaptation; Ecology; Ecotones; Environmental factors; Environmental gradient; Environmental Management; Feedback; Freshwater ecology; Freshwater environments; Fundamental and applied biological sciences. Psychology; General aspects; Habitat; Hardwoods; Hydrology; Landscape; Landscape Ecology; Landscape/Regional and Urban Planning; Life Sciences; Mangroves; Marshes; Nature Conservation; Numerical simulations; Pattern formation; Plant ecology; Pore water; Positive feedback; Precipitation; Research Article; Salinity; Salinity effects; Soil hydrology; Soils; Sustainable Development; Synecology; Topography; Vadose water; Vadose waters; Vegetation; Vegetation type; ASW, USA, Florida; Mangrove vegetation; Ecotone; Positive feedback; Environmental gradient; Vegetation aggregation; Individual-based model; Individual based model; Spatial variation; Salinity; Aggregation; Soils; Spatial distribution; Feedback; Mangrove; Vegetation
• ISSN: 0921-2973; 1572-9761
• DOI: 10.1007/s10980-011-9689-9

Coastal vegetation of South Florida typically comprises salinity-tolerant mangroves bordering salinity-intolerant hardwood hammocks and fresh water marshes. Two primary ecological factors appear to influence the maintenance of mangrove/hammock ecotones against changes that might occur due to disturbances. One of these is a gradient in one or more environmental factors. The other is the action of positive feedback mechanisms, in which each vegetation community influences its local environment to favor itself, reinforcing the boundary between communities. The relative contributions of these two factors, however, can be hard to discern. A spatially explicit individual-based model of vegetation, coupled with a model of soil hydrology and salinity dynamics is presented here to simulate mangrove/hammock ecotones in the coastal margin habitats of South Florida. The model simulation results indicate that an environmental gradient of salinity, caused by tidal flux, is the key factor separating vegetation communities, while positive feedback involving the different interaction of each vegetation type with the vadose zone salinity increases the sharpness of boundaries, and maintains the ecological resilience of mangrove/hammock ecotones against small disturbances. Investigation of effects of precipitation on positive feedback indicates that the dry season, with its low precipitation, is the period of strongest positive feedback.