2016-12-12 General Committee - Attachment 1 to Item 6 - Biodiversity Assessment Report

                                                 Noosa Biodiversity Plan – Biodiversity Assessment Report




colonies have occurred at Palmwoods, in nine colonies in northern New South Wales, in Ipswich and at
Townsville (Low, 2011). A flying fox die-off event in Sydney was recorded by Watkin Tench in 1793 (Low,
2011), showing this to be a natural occurrence, but a higher incidence of such events, with greater
mortality rates, can be expected in future. Black Flying Foxes Pteropus alecto are particularly vulnerable
to mass die-offs due to high temperatures (Low, 2011). Flying fox colony sites have changed over the
years, with many now in lowland urban areas (Low, 2002), which experience higher temperatures than
the rainforest gullies often used in the past.

Koalas may be also be particularly susceptible to heat stress in humid areas due to their low vagility and
reliance on panting to remain cool. Koalas can survive in arid areas where temperatures rise above 40°C,
but do not occur in coastal Queensland north of latitude 18°S (Low, 2011). Clifton et al. (2007) attribute
this to high night temperatures and humidity reducing the effectiveness of panting. As such, high
temperatures in humid lowland areas, such as Noosa, may significantly reduce the ability of koalas to
keep cool during the prolonged heatwaves and greater frequency of hot nights that are predicted.

In general, birds and other large mammals are very mobile and have the capacity to respond to rising
temperatures by moving location within a given area (Low, 2011). Based on current ecological and
physiological knowledge, reptile experts understand that most Queensland reptile species will survive
higher temperatures by adjusting behaviour, remaining deep inside refuges (where available) when
temperatures rise too high (Low, 2011).

Greater intensity, spread and frequency of bushfires
The lowland rainforests of Noosa are particularly vulnerable to the impacts of increased bushfire activity.
Average annual rainfall volumes are projected to decline across the Sunshine Coast, with more winter
rain and less rain in other seasons (SCC, 2010). This reduction and seasonal shift in rainfall, combined
with an overall reduction in soil moisture, more frequent El Niño’s, and increased fuel loads during intense
La Niña years, is likely to result in major changes to fire regimes and major shifts in plant composition
competitive relationships, particularly from rainforest to eucalypt forest (Steffen et al., 2009, Low, 2011).

Fire is a more significant cause of rainforest death than drought (Low, 2011), and a more important
determinant of rainforest distribution than rainfall. With higher temperatures and less summer rainfall,
there is an increased probability of fires penetrating into rainforest communities, causing a shift to fire-
tolerant species and away from cool-adapted species (Steffen et al., 2009). Fire is likely to exert a strong
influence on the rainforest extent in eastern bioregions (including Noosa), where rainforests are predicted
to suffer from increased fire damage leading to weed invasion (Low, 2011). In particular, lantana Lantana
camara fuels intense fires that seriously damage rainforest margins and, by invading damaged areas,
leads to a permanent loss of habitat. In wetter rainforests near the coast green panic Megathrysus
maximus also increases the risk of damaging fires where it occurs (Low, 2011).

Shifts in ecological community compositions due to altered fire regimes and plant competitive
relationships are a particular concern in regions where plants with ‘tropical’ and ‘temperate’ distributions
overlap, such as southeast Queensland (Low, 2011).

Loss of saltmarshes and swamps
Noosa Shire contains low-lying ecosystems and vegetation communities that are vulnerable to the
projected impacts of a warming world. Landward movement and encroachment of estuarine and coastal
ecosystems (especially by mangroves) may be at the expense of other communities such as saltmarsh,
freshwater wetlands and swamps (Steffen et al., 2009, Low 2011).

Although saltmarshes have the potential to relocate landwards in response to rising sea levels, they
occupy higher land than mangroves and their relocation will more often be blocked by seawalls and other


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