An Integrative Approach To Assess the Interaction Between Water Relations of Vegetation and Hydrodynamics of Coastal Sandy BeachesEPA Grant Number: U916095
Title: An Integrative Approach To Assess the Interaction Between Water Relations of Vegetation and Hydrodynamics of Coastal Sandy Beaches
Investigators: Greaver, Tara L.
Institution: University of Miami
EPA Project Officer: Michaud, Jayne
Project Period: January 1, 2002 through December 31, 2002
Project Amount: $141,816
RFA: Minority Academic Institutions (MAI) Fellowships for Graduate Environmental Study (2002) RFA Text | Recipients Lists
Research Category: Academic Fellowships , Fellowship - Natural and Life Sciences , Biology/Life Sciences
Global climate change should cause an increase in the rates of sea-level rise (IPCC 2001); therefore, ocean water will intrude farther inland, affecting soil hydrology as it proceeds and consequently altering vegetation dynamics. Coastal dunes will be among the first habitats affected by sea-level rise. The objective of this research project is to provide an understanding of how dune species uptake ocean water under current conditions to: (1) aid predictions of how they will respond to increased ocean-water input to soil waters; and (2) help develop our understanding of how species may be used as indicators to evaluate the effects of sea-level rise.
Distribution of plant species in many coastal communities is linked to the salinity of soil water because of species-specific physiological tolerance. In sand-dune communities, the distribution of vegetation has been studied in relation to gradients of above-ground environmental factors that occur from the sea to the inland such as salt water spray, sand abrasion, and sand cover. Salt deposition onto surface soils by ocean spray is considered the dominant variable governing plant distribution. However, the relationship between the soil hydrology of the dune system, plant distribution, and plant physiology has not been investigated extensively. Ocean water may have a more extensive role in determining plant distribution than by salt spray alone. Ocean water may enter deep vadose soils by two mechanisms: ocean-water intrusion and tidal pumping. The combination of these mechanisms in addition to salt spray makes it likely that ocean water enters the dune soils and mixes with ground- and rainwater. Ocean water entry to dune soils is likely greatest proximal to the source where it strongly would affect vegetation.
I will investigate the interactions between plant distribution, plant physiology, and vadose hydrology (from water table to soil surface) in the coastal dune ecosystem by comparing areas that are proximal and distal to the ocean. Stable isotopes are used as water tracers to identify spatially and temporally driven patterns of ocean-water distribution in the soil and uptake by vegetation in situ. In conjunction with stable isotopes, a suite of techniques, including gas exchange and water-potential measurements, determine how the spatial and temporal variation of hydrologic conditions affect the physiological status of the vegetation. This research project will determine how water-harvesting strategies and physiological characteristics respond to different and fluctuating levels of ocean water; thus, the results will provide a basis from which to assess the impact of sea-level rise on coastal dune communities.