Envirothon Invasive Speicies: Regional Resource

Exotic species

species that arrive to a location outside of their natural range without help

• also under the “alien species” category

Are exotic species likely to become invasive?

No

why are exotic species not likely to become invasive?

because only 1% of exotic species introductions lead to established populations capable of increasing and spreading

• this process may take decades before they become invasive

Alien species

A new specie in a given area whose presence is due to human involvement

Casual/Introduced species

species that may flourish and even reproduce occasionally as aliens outside cultivation or captivity in an area

• but they eventually die ut becuase they do not form self-replacing populations and rely entirely on repeated introductions for their persistence

Natural/Established species

alien species that sustain self-regenerating populations for a reasonable period of time, unsupported by and independent of humans

Invasive specie

exotic species that establish themselves in an ecosystem at the expense of other species

What types of harm are invasive species likely to cause

• Economic harm

• Environmental harm

• Harm to native speices

what does the impact of a specie on an ecosystem often depend on

• Location

• time of year

• weather conditions

• number of individuals

• etc

note: same species may have little impact on native species in one area but cause devastation in another

What is the typical cause of invasive specie spread and expansion

• anthropogenic (human) activities

Examples of common invasive species found in our lawns and gardens

• dandelions

• kentucky bluegrass

• periwinkle

• lily of the valley

How do invasive species threaten an areas biodiversity

• by overwhelming native species

• damaging habitats

• disrupting food sources

• introducing parasites and disease

5 main characteristics of invasive species

1. Few natural enemies

2. High reproductive rates

3. high survival

4. good dispersal

5. They are aggressive competitors

Identify and describe the 4 steps in the pathway of introducing an invasive speice

1. Transport

   1. human activities move a specie beyond its natural range

2. Introduction

   1. arrival at new location

3. Establishment

   1. producing viable and self-sustaining population

4. Spread

   1. dispersal and movement in a new region

what are two factors whos direct consequence is the spread of invasive species

• expanding transport and trade

  • aka global trade market

what was the tropical ornamental plant from asia that has established itself as an invasive spcies in austrialian rainforests

The Hiptage

Where were Burmese pythons released and what did it lead to

• released and established in the florida everglades national park creating devastating impacts

• led to massive removal project where over 15,000 snakes have been removed

what did a 2012 study on the impacts of burmese pythons find

• population of raccoons, opossums, and bobcats in the park have all been reduced by 87-999% since the introduction of pythons

• marsh rabbits, cottontail rabbits, and foxes have completely disappeared

how are aquatic and marine invasive species often introduced

• through hull fouling and ballast water

Impact of Biofouling on invasive species spread

(1 global statistic, 1 hawaii statistic)

over 2/3 of all non-native algal species globally and about ¾ of all non-native marine inverterbrates in Hawaii were introduced through biofouling

how were purple loosestrife (wetland plant) introduced into north america by european colonists

introduced when seeds were transported in soils used to balance european sailing ships

approximately how man spcies are transported through Ballast water in a day

7000 species daily

Examples of unintentional introductions (8)

1. plant products

   1. seeds, garden supplies, firewood

2. ballast of ships

   1. transporting waterm soil, etc

3. soil, sand and gravel

4. Fright, packing materials, machinery, equipment

5. canals and changes to waterways

6. recreation and tourism

7. livestock or other animals

8. escape of non-native wildlife in captivity

   1. exotic pets

Examples of intentional introductions (6)

1. agriculture

2. aquaculture and recreational harvest

3. biological control

4. releasing species through horticulure or pet trades

5. intentional stocking or introduction

6. illegal release

the movement of a species from a non-native immigrant to an invasive species often involves a ___ or a ____ period, followed by a period of ____ exponential _____ in population.

the movement of a species from a non-native immigrant to an invasive species often involves a delay or a lag period, followed by a period of rapid exponential increase in population. The rise in population will continue untill the inasive species reaches the limits of its new range and the population growth rate will then stabilize.

spread: secondary movement

secondary movement occurs once the species has been introduced to a new area and starts spreading further into other locations nearby.

how further spread happens

through natural (eg. active natural movement) or through use of other animals (such as fur of animals, bottom of waterfowl feet, seeds in digestive tract, etc), or human assisted movement

how long until a new species becomes invasive? lets talk about the lag phase

the gap - the time between a plant introduction and its discovery as an invasive species - is. called the lag phase. While the lag phase of many invasive species is relatively shot (a few years), for some plants, it can last several decades or longer.

caues of lag phase for plants

1. low initial numbers

2. evolution

   1. needs time to adapt to local environment before spreading rapidly

3. change in local environment