Ecosystems
at Risk .
“
Australia has a poor record of managing and using aquatic and wetland
resources. Throughout the country, aquatic habitats such as rivers, swamps and
lakes have been degraded and destroyed for short-term unsustainable gain. This
short-sighted behaviour has placed the well-being of future generations in
jeopardy.
Maintaining
Australia's aquatic habitats and their associated biodiversity in a healthy
state is fundamental to their existence and our well-being. In a healthy
state, aquatic and wetland resources can also provide many goods and services
of great benefit to society that have often gone unheralded (apart from a
water supply)."
An
excerpt from Australia’s Aquatic and Wetland Resources: The Critical
Challenges, Australian Society for Limnology (February, 2000)
Many
of the wetlands of the lower Hunter floodplain have been significantly altered
since European settlement. Almost 960;0 have been grazed to some extent, while
the water regimes of many wetlands have been altered by drainage or
obstructions to water flow.
The
wetlands at Shortland have been substantially altered over the years for
various land uses. Since 1985 they have been restored to provide habitat for
wetland flora and fauna and to demonstrate sustainable management practices.
In restoring the site for conservation uses, The Wetlands Centre has aimed for
a balance in its development to design for both people and wildlife. This
results in many management issues, which can be considered by students.
In
investigating the wetlands as an Ecosystem at Risk, students will be
investigating the unique characteristics of this wetland and posing the broad
question:
To what degree are wetlands robust and resilient and in what ways are
they vulnerable?
Students
will collect evidence to answer this question by investigating ecosystem
features and functions using three different methodologies. Students will then
consider management strategies and conservation strategies.
Students
will investigate:
·
The biophysical
interactions of a wetland ecosystem. .The reasons for the location of the
wetlands
·
The sources and
quality of water which flows into the wetlands
·
The way in which
short-term and long-term change affects ecosystem functioning.
·
.The management
issues and requirements for this site.
Part
One:
This
section involves three activities, each requiring approximately 45 minutes. If
time permits, all students will rotate through each activity. If time is short
students can complete one of the three activities in groups and share the
information in Part Two.
Biophysical
interactions: Use
equipment to collect and interpret data on biophysical interactions
Water
source & water quality:
Use maps to explain the location of the wetlands and identify the sources and
entry points for water from the surrounding catchment
Response
to change: Use
observations and photos at particular locations on the wetland site to
identify short-term and long-term changes which impact on ecosystem functions
and to give examples of both natural and human-induced change
Part
Two:
Students
will present their findings to the whole group. The whole group will discuss
the value of different methodologies and assess how the information assists in
answering the major question.
Part
Three:
All
students in small groups will then answer the questions: What are the stresses
on this ecosystem: How do we know? Impacts due to natural stress
Impacts
due to human activities
What
evidence do we have that system is coping?
What
strategies will insure ecosystem management and protection Example: Management
Plan, Legislation
Students
wiII choose one of the Wetlands Values and Functions Sheets and explain
how their particular value or function applies to The Wetlands at Shortland.
Students
select an example of a policy or legislation and discuss how it might impact
on the conservation and/or management of wetlands in general OR these wetlands
in particular.
Hypothetical:
Opening of Ironbark Creek Floodgates.
Students
are presented with background information and modelling maps, which they use
to respond to the following questions
·
What changes can we
predict?
·
In what way will this
influence: Resilience, Vulnerability on this site?
·
What are the
short-term and/or long-term management implications?
This list of issues aims to highlight
some key wetland issues specific to The Wetlands Centre. They should be
considered as a part of, a broad overarching question:
To what degree are wetlands robust and
resilient and in what ways are they vulnerable?
Invasive species: plant or animal
What is the extent of the invasive
species problem on the site?
Competing demands: habitat vs people
How do you design for people access and
protect the habitat at the same time?
Restoration: response to historical
land uses
How well and to what extent, has the
site been restored?
Creating. providing and protecting a
habitat for biodiversity
How is the site providing for
biodiversity values and acting as a refuge for wildlife?
The
Wetlands Centre, Australia Location: Central Coastal Plain at 3253' 5,15142' E.
Located on the
edge of Hexham Swamp in the suburbs of
Newcastle. Bioregion: Sydney Basin. Area: 45 ha.
Elevation: O m AsL.
Wetland types according to Ramsar
Classification System as featured in the Directory of Important Wetlands in
Australia :
The Shortland Wetlands System is a
remnant floodplain wetlands on the edge of Hexham Swamp. The wetlands are
located within the grounds of The Wetlands Centre, Australia, in the suburb of
Shortland in the Hunter region of New South Wales, Australia. The enclosed
wetland reserve also houses a Visitors Centre and a range of facilities for
visitor access. Situated on the eastern edge of Hexham Wetlands, it has a
physical connection with the Hunter Estuary through Ironbark Creek. It is owned
and operated by a non- profit, company, and is run by a small paid staff and a
large corps of volunteers.
The Centre was established in 1985 to
encourage conservation of wetlands and their flora and fauna; to promote public
awareness and education on the value of wetlands; to provide facilities for the
scientific study of wetlands and; to cooperate with other like-minded
organisations both within Australia and throughout the world. Previous land-uses
on the site included market gardens, a land fill site and a football club.
Today the site has been rehabilitated
to provide a network of fresh and brackish ponds, providing habitat for a
diverse range of wetland flora and fauna, including approximately 40 species of
waterbirds. The freshwater swamp forest is used for breeding by 2000 breeding
pairs of four egret species, and as an evening roost by approximately 4000
Australian White Ibis and Straw-necked Ibis. At least 20 other bird species have
bred on the site. The Wetlands are filled by local rainfall and run-off from
surrounding land.
Waterfowl conservation projects at The
Wetlands Centre include re-introduction of the Magpie Goose and captive breeding
of the Freckled Duck. Later this year work will begin on a pond to support
re-introduction of Green and Golden Bell Frog in partnership with the Kooragang
Project and Newcastle University.
Threats to the ecological character of
the wetlands which must be managed include pest plant species such as alligator
weed, pest animal species such as foxes, excessive demands on forested wetlands
by breeding bird colonies and eutrophication caused by nutrient-laden run-off.
Human Impacts on the site are best
demonstrated by the invasion of exotic plants along the boundary of the site,
which interfaces with the homes in Shortland. Many exotic plant species have
"escaped" from local gardens, either through the plants ability to
spread or through the practice of throwing garden waste "over
the fence". Some exotic species
have become well established. This becomes a maintenance problem and an
education problem.