Invasive Plants

1
Invasive Plants

• Monica Vernon
• Ecol 474

2
What is an Invasive Plant?

• An invasive plant species is defined as one that
  has or is likely to spread and develop
  self-sustaining populations, and become dominant
  or disruptive.
• Invasive plants interfere with ecosystem function
  and are a serious threat to biodiversity and
  productivity in different habitats.

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Also Known As

• Invasive plants are also known by names such as
  weeds, and include adjectives such as alien,
  noxious, exotic, transient, or foreign, to name
  just a few

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Why Does it Matter?

• Invasive plants are second only to habitat loss
  and degradation in endangering native plant
  species. They are also the second most serious
  threat to biodiversity in all ecosystems.
• Negative effects of the invasive plants can be
  seen in many factors including competition for
  resources, hybridization, introduced or increased
  nitrogen fixation, and increased sedimentation
  among other things.
• Invasive weeds in wetland areas cause problems
  for water resource managers, can inhibit drainage
  and interfere with intended uses for a body of
  water, and also provide a habitat for vectors of
  diseases. A recent estimate on the cost of
  invasive plants was put at 35 billion a year.

5
History

• Plants original uses were medicinal and
  agricultural, but over time with society
  acquiring more disposable wealth, they also
  became a hobby with ornamental gardening and
  experimentation. Experimental gardens, commercial
  nurseries, and international trade of plants and
  seeds flourished
• Todays interest in horticulture and plant
  exploration is one of the pathways of invasive
  plant introduction and spread. The United States
  has encountered various problems for over a
  century due to invasive plants, largely because
  of ornamental use or intentional introduction

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How are They Being Spread?

• The Internet
• Rarely differentiates between the plants that are
  invasive and those which are not.
• Every aquatic plant that was listed on the
  federal or state noxious weed list was found on
  the internet. Because many are pretty and easy to
  grow there are problems with them being sold.
• Easy access to the internet has increased the
  spread of invasive species. Species may now
  repeatedly, on larger scales than ever, be
  introduced to new areas

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How are they Being Spread?

• Botanical Gardens and Arboretas
• Usually more knowledgeable and have greater
  lengths of time in observation of plant behavior,
  issues still arise such as invasive species being
  mistaken for non-invasive and problems with a
  period known as lag time.
• One may believe a new plant safe and noninvasive
  due to the fact it was observed for a period of
  time without displaying characteristics of an
  invasive plant, but many invasive plants do not
  begin to invade for many years. Lag time for many
  species has still not been determined. A few
  reasons for this is the fact some of the invasive
  plants only become invasive after changes in
  environment, genetic changes within the plant, or
  introduction of pollinator.

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How are They Being Spread?

• Many Hobbyists/Nurseries usually dont have the
  knowledge to recognize invasive species. Even
  those who have some knowledge of invasive species
  very often misidentify an invasive species for
  one they think to be safe.

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What Can Be Done?

• The results of a recent study brought two main
  issues to the forefront. The first issue is that
  people need to know what exactly is invasive.
  Many stated if they knew about the invasiveness
  of a plant they would not be involved with a
  purchase. The second big issue that arose from
  the study was that the best way to inform and
  educate most people as to what plants are
  invasive would be to place a label on the plants
  in the nurseries

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What Has Been Done?

• Environmental and economic damage continue to
  rise because of invasive plants. Though the
  United States government has made laws against
  importation of species listed in the Federal
  Noxious Weed Act (White 2001), there are still
  very few restrictions on importation of plants.
  We do not have screening for invasive plants
  before introduction, though Australia and New
  Zealand have already implemented such regulations
  (Hoddle 2001). Though President Clinton signed an
  executive order for an Invasive Species Council
  to be developed, little has still been done to
  reduce the harm invasive plants have caused
  previously or will cause in the future.
  Controlling the distribution of invasive plants
  has also been hindered because of the threat of
  conflict with international trade agreements
  (White 2001).

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What To Do

• If all groups involved work together to pool
  resources and stand up as a unified front, there
  will be a better chance for action. A national
  plan is needed that includes development of
  regulations, education programs, plant lists, and
  plant labeling (White 2001). A national plan, if
  implemented, will take much gathering of
  information, analysis, and cooperation between
  all involved. There must be effort to also
  locate and prosecute those who intentionally
  grow, sell, or distribute invasive plants (Kay
  2001).
• The best thing we can do as a country to prevent
  further damage is to start educating our citizens
  of the dangers of aquatic plants and their
  effects on ecosystems around the world.

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References

• Hoddle, Mark S. Restoring Balance Using Exotic
  Species to Control Invasive Exotic Species.
  Conservation Biology 18.1. (2004). 17 Septmber
  2006
• lthttp//www.balckwell-synergy .com /links
  /doi/10.1111/j.15231739.2004.00249.x/pdfgt
• Kay, Stratford H., Steve Hoyle. Mail Order, the
  Internet, and Invasive Aquatic Weeds. J. Aquat.
  Plant Manage. 3988-91 (2001). 14 September 2006
• lt http//www.apms.org/japm/vol39/v39p88.pdfgt
• MacIssac, Hugh J., Robert J. Colautti. A
  Neutral Terminology to Define Invasive
  Species. Diversity and Distributions 10,
  135-141.(2004) 17 September 2006
  http//www.blackwell-synergy.com/links/doi/10.1111
  /j.1366-9516.2004.00061.x/pdf
• White, Peter, Sarah Hayden Reichard.
  Horticulture as a Pathway of Invasive Plant
  Introductions in the United States. BioScience
  51.2(2001). 17 Septmber 2006 http//www.bioone.org
  /perlserv/?requestget-documentissn0006-3568vol
  ume51issue2page103gt