Metropolitan Melbourne Investigation - Victorian Environmental ...

4.2 Impacts on biodiversity
Major land use change in metropolitan Melbourne over
the last 200 years has greatly altered many ecosystems
and species compositions. Habitat loss and habitat
fragmentation and degradation continue to impact on
Melbourne’s biodiversity. More erratic rainfall, increased
temperatures, more frequent extreme weather events
and sea level rise associated with climate change will
exacerbate these existing stressors for many plants
and animals.
It is difficult to predict the exact impacts of climate change
on flora and fauna due to our incomplete understanding
of how ecological processes will interact with one
another. Impacts may include changes in the distribution,
abundance and life cycle of flora and fauna species. For
example, a global analysis of biodiversity distributions
shows a profound shift in species ranges over a wide
range of taxa with movement of about six kilometres per
decade toward the poles. 27 Similarly, the early emergence
of a butterfly species in Melbourne has been attributed
to climate change. 28 Some species that are not currently
threatened may become so.
Maintaining and extending ecological connectivity in
metropolitan Melbourne will improve the resilience of flora
and fauna species and is likely to aid adaptation to climate
change. Some species may be able to expand their range
by extending into areas with decreased competition
or disease. 29 It is unlikely, however, that enhancing
connectivity will be sufficient to protect all species. For
example, the climate in which some species currently
exist will over time either cease to exist or will shift to
regions with unsuitable conditions for the establishment
of identical or appropriate habitats.
One submission likened the metropolitan area to a
drought refuge for some native plants and animals. Many
urban parks and golf courses are well-watered, and can
provide food resources (such as nectar-bearing plants) for
fauna during periods of drought. Wetlands such as the
Edithvale–Seaford Wetlands and other areas such as the
Western Treatment Plant at Werribee are also recognised
as important drought refuges for a number of bird species
when inland lakes and wetlands dry out. The role of
these areas as drought refuges may become increasingly
important in the context of climate change.
The final report for VEAC’s Remnant Native Vegetation
Investigation 12 focused on opportunities to improve
ecological connectivity. Its recommendations were
aimed at improving biodiversity protection and ecological
connectivity in fragmented landscapes. It recommended
that government progressively establish a program
for improving the link between statewide biodiversity
strategies and priorities and local scale opportunities.
Chapter 3 of this report provides further discussion
on enhancing Melbourne’s biodiversity, including
recommendations for enhancing the protection of remnant
native vegetation on public land and across the landscape.
Several submissions commented on the impact of climate
change on biodiversity, including changes in ecosystem
distribution, composition and function, and changes
in species distribution. Submissions discussed the
importance of remnant native vegetation on public land for
providing new habitat and movement corridors for species
that may shift in range due to climate change. Others
discussed the importance of cross-tenure management
across private and public land to help mitigate the impacts
of climate change on flora and fauna.
Above: Lake Borrie at the Western Treatment Plant
is recognised as an important drought refuge for
many bird species and is part of a Ramsar wetland of
international importance.
* Treatable public land is the available area of public land in which planned burning can be safely and effectively undertaken to reduce fuel loads. 26
28