Notes: The Trouble with Thypha (Cattail)

Introduction
The following are some of my notes from a lecture I attended at the headquarters to a national park in Indiana on wetland restoration and cattail invasion.  Wetlands are any area of land that is soaked with water for most of the year (but is not just open water such as in a lake).  Normally, wetlands have a diverse array of aquatic plants such as various grasses, sedges, waterlilies, etc.  Within the last few centuries, however, many wetlands - both natural and man-made - are quickly giving way to a monoculture of cattail (Thypha spp.), a reed that frequently grows in shallow water (see Figure 1).  This lecture I attended discusses how and why cattail has become an invasive species, what people can do to monitor the situation, and how to control the invasion of cattail reeds.

Figure 1:  Cattail reeds in a marsh.  Photo by Joy Marburger
  • Cattail considered invasive since the 1950s.
  • Cattail is in the Family Typhacea and its only genus is Typha.
  • Has wind-dispersed pollen and seeds (both are very small and easily airborne)
  • The structure of a cattail includes an extensive system of rhizomes.  The rhizomes from when a new plant is only about 6 inches in height!  It also consists of a root, steam, and a leaf (see Figure 2).  
Figure 2:  The basic structure of a cattail.
Figure 3: Thypha latifolia (a) and Typha angustifolia (b)
The native species of cattail, prevalent in pre-Colonial times, was Typha latifolia (Figure 3a).  The non-native species, likely introduced via the movement of ships from Europe to the United States, is T. angustifolia (Figure 3b).  The main morphological differences between the two species, as shown in Figure 3, is the gap that the native species has between the female inflorescence and the male section of the plant.  
  • The two species are now hybridizing.  
  • Hybrid species has highly variable features in terms of height, length, and where it grows.
  • Creates monocultures (Figure 1) and it changes the hydrology of wetland ecosystems, since cattails use up a lot of water and essentially dry out the marshes.  
Causes of Spread: Genetic Analysis
  • There are various causes for the spread of cattail.
  • Genetic analysis of cattail and cattail hybrids - a combination of genetic and environmental factors yield the plant's characteristics.  Phenotype = genotype + Environmental variables
  • Microsatellite DNA analysis used to determine parentage
  • Sequences (the different instances of the enzymes found in DNA) should match for a given species:
ABAB       CDCD
ABAB       CDCD
  • A hybrid would be expected to have a combination of two different species:
ABABCDCD

Causes of Spread: Seedbank Study
  • The introduction of T. angustifolia to North America gave it a good start
  • Disturbance from the industrial era and the movement of ships into the Great Lakes with contaminated ballast water
  • T. angustifolia has similar breeding mechanisms and same chromosome numbers to the native cattail (T. latifolia).  
  • Continues to spread across landscape via rhizomes and some fertile seeds
  • Extensive genetic intermixing - it is able to colonize various wetland habitats
  • Native cattail may go extinct through hybridization.  
  • Cattail more prevalent in seedbanks in some areas and not as much in other areas - despite similarities between two given localities.  
Cattail Management in Wetlands
  • Animal grazing is ineffective (muskrats cannot keep up with fast cattail growth)
  • Mechanical measures ineffective because of rhizomes
  • Hand pulling for small areas can work
  • Prescribed burning ineffective because it can cause peat fires and it does not neccesarily kill cattail rhizomes
  • Chemical control is used!  Glyphosate or diquat herbicide is used.  Both require the addition of a surfactant to stick to cattail plants and minimize damage to other plants and animals.  
Remedy?
  • Use prior research on cattails and cattail management
  • Develop historical documentation of what vegetation existed prior to invasion
  • Survey existing flora, fauna, seedbanks, soils, etc.
  • Develop restoration goals for where cattail will be controlled
  • Use restoration management techniques to restore pre-colonial vegetation communities, keeping in mind climate change.  
  • Use demonstration sites to create public awareness
  • Volunteer!  Sign on to the USGS's Cattail Volunteer Monitoring Project:  http://nwrcwebapps.cr.usgs.gov/cattail/

Cattail (seen just before treeline in background) encroaching into a native fen wetland in a national park in Ohio.  Photo by Joy Marburger.  


Comments

Post a Comment

Popular posts from this blog

Windy City Cactus: Eastern Prickly Pear Cactus

Image
When you think of Chicago, you probably don't think of sand dunes, prairies, or large oak trees.  Yet despite Chicago being the third largest city in the United States and heavily impacted by urban sprawl and industrial blight, there remains thousands of acres of greenspace with wetlands, open woods, sandy beaches...and some rather surprising flora. The pictures below were not shot in Arizona nor in Southwest California, but were in fact taken at the 63rd street beach on a recently restored sand dune near Hyde Park in Chicago, Illinois.  They are the eastern prickly pear cactus ( Opuntia humifusa ) . Figure 1:  Eastern prickly pear cactus, a native plant to the Chicago region and the only native cactus to the Great Lakes area.   The genus Opuntia is much more common out west where they have many different species, but in the Great Lakes and Midwest regions, the eastern prickly pear is the only native cactus.  It tends to be a little bit smaller than its western counterp
Read more

Virginia Pineapple? The fascinating family of Bromeliaceae

Image
Who hasn't tried pineapple before?  It always seems to end up in fruit salads at family reunions, there's always someone in the crowed ordering "Hawain pizza", and the grocery stores always seem stocked full with showy pineapples displaying their rough-textured, compartmentalized skin with bizarre green leaves on top (Photo A).  To most people living in temperate regions such as most of the lower 48 United States, pineapples are nothing short of exotic and unusual - and not like anything we have growing in the wild on our landscape...or do we? Photo A:  A pineapple grows wild along a woodland edge in a tropical park in  Ecuador, South America. Pineapples are in the family Bromeliacea, which includes a large group of mostly tropical plants that are primarily  epiphytes - plants that grow on top of other plants (see photo B). Photo B: Bromiliads, shown in the center of this photo, are a common group of tropical epiphytes throughout rain forests and
Read more

Natural Notes: Native Sunflowers

Image
September is the month of yellow, and for gardeners the easy-to-grow and popular choice of flower  is the Annual Sunflower ( Helianthus annuus ) which adorns garden borders and roadsides across the Chicago Region.  Numerous cultivars of this urban weed have been developed, and the source of commercial sunflowers and sunflower oil are derived from the Annual Sunflower (figure 1).  Figure 1:  Annual Sunflower growing  at the Taylor Street Farms community garden in Chicago.   But prior to European settlement, the Chicago region was largely absent of this tall and showy late-summer wildflower, whose range historically included the south-central United States into the plains and grasslands just to the east of the Rocky Mountains.  Instead, the prairie landscape of Northern Illinois would have been adorned with several species of native sunflowers and sunflower-like plants (figure 2).  Figure 2:  Although virtually absent of the notorious Annual Sunflower, the prairie landscape of N
Read more