Biology/ecology : Biology/ecology Found from 0-2100 m (6888 ft)
“Facultative phreatophyte”: can draw water from underground resources but once established it can survive without access to groundwater.
Ground water 1.5-6 m below soil surface: forms dense thickets,
Groundwater > 6 m: forms open shrublands.
Flowers insect pollinated, wind dispersed seeds
Adult trees can produce 250 million seeds per year!
Seeds can germinate within 24 hrs after contact with water
No seed dormancy requirements, no seed bank
Biology/ecology : Biology/ecology Can produce roots from buried or submerged stem fragments (“vegetative reproduction”)
“Halophyte”: High tolerance for alkaline or saline soils
Especially higher than natives
36,000 ppm vs. 1500 ppm
Has salt glands in leaves
Salts 5-15% of dry weight of leaves
Tamarisk seedlings grow more slowly than native riparian plants.
Mature plants are susceptible to shading.
Why is it so successful? : Why is it so successful? Good competitor: highly fecund, long lived, tolerant of flooding, drought, and nutrient stress
Alteration of natural flow in rivers due to dams
Cottonwoods and willows need spring floods for their seeds to germinate
Tamarisk has not become established in rivers that experience large floods and where spring flooding predominates
Increased salinity of rivers
Irrigation return and evaporation from reservoirs
Resprouts after flooding and fire
How does Tamarix change the functioning of riparian zones? : How does Tamarix change the functioning of riparian zones? Replaces native vegetation
Consumes a lot of water
35% more rapidly than native vegetation, denser stands
Reaches deeper into groundwater farther from river channel
Increases soil salinity
Takes up salt from soil and then deposits it above ground from salt glands in leaves or from shedding leaves (salt conc in leaves 5-15%)
Traps sediments sedimentation
Colonizes the islands that it creates
Leads to more narrow, more shallow river channels, increasing risk of overbank floods
Increases fire frequency
Heavier fuel loads, more flammable leaves, sprouts back after fire
Poor habitat for native species
Lower bird density and diversity