Survival of Plant Species as a Function of Salinity and Slope Position

Abstract

An experiment was conducted during 1995-1997 at Truscott Brine Lake, Truscott, TX to determine whether any of 38 salt tolerant plant species could survive salt conditions at Truscott Brine Lake and tolerate the summer heat and winter cold of northwest Texas.  Little is known regarding survival and growth of species native to salt marsh conditions of southern United States coastal regions with respect to climate which is more xeric and having a wider range of temperature extremes than coastal areas.  The objective of this study was to examine the effect of pond salinity and shoreline position (proximity to pond edge) on survival of salt tolerant species and to determine which species may have potential to survive in this environment.  Species selection was based on salt tolerance in Gulf and Atlantic coastal areas and in arid western U.S.  Species were planted in and around 1-acre circular research ponds, 3 filled with high saline water (termed ‘salt water’) and 3 filled with less saline water (termed ‘fresh water’).  Species were planted in spoke arrangements beginning near the center of each pond and radiating outward.  Each pond contained a spoke for each species, spokes were spaced uniformly, and species were assigned randomly to spokes within a pond.  Three slope positions were designated on each pond spoke to correspond to 3 levels of plant submergence.  These levels were position 1: never submerged; position  2: periodically submerged; and position 3: continuously submerged.  Water was pumped periodically into each pond to maintain predetermined water levels.  Species survival was affected by species genetics, slope position, pond x slope, species x slope, and pond x species x slope interaction.  Species survival decreased as the level of submergence increased.  In the summer of 1995 there was little effect of slope on species survival, but by the fall of 1997 slope positions 1, 2, and 3 had only 48%, 29%, and 9% survival, respectively.  Survival rate decreased by 20% with each slope increment. Based on percentage survival sand cordgrass, saltmeadow cordgrass selection 9067788, and common reed are viable species for use on all slopes in fresh water.  Saltmeadow cordgrass var. ‘Sharp’, ‘selection 9067788', and ‘Flageo’ along with common reed and sand cordgrass are viable species in salt water.