Local Biodiversity Strategy: - Shire of Kalamunda

Habitat fragmentation has many detrimental impacts including:
• Reduced habitat for individual species and isolation of species living in an
area;
• Interference with the ability of populations to disperse and recolonise areas
after disturbance (such as fire) or senescence;
• Decreasing population size to below the threshold where it can be selfsustaining
through reproduction; and
• Magnification of the negative impact of surrounding land uses (edge effects)
in comparison to corresponding areas of habitat that are not fragmented
(Local Government Biodiversity Planning Guidelines for the Perth Metropolitan
Region, 2004).
4.5 Altered Hydrological Regimes / Water Quality
Plants and plant communities are strongly influenced by water availability.
Urbanisation has significantly altered water regimes in the Shire and therefore the
water available to plants and plant assemblages.
Wetlands on the Swan Coastal Plain, for example, have historically been used for
stormwater discharge. Some wetland areas that were previously seasonally
inundated have become permanently inundated which has led to death of some flora
species.
Excessive nutrients, sediments and pollutants can also have a significant effect on
endemic vegetation, wetlands and waterways. Excessive nutrients and pollutants
contribute to algal blooms (eutrophication events), death of aquatic life in wetlands
and promote the spread of weeds in both upland and wetland natural areas (Local
Government Biodiversity Planning Guidelines for the Perth Metropolitan Region,
2004).
4.6 Erosion
Erosion is evident along the numerous
creeklines within the Shire of Kalamunda which
causes physical degradation to these natural
areas. Erosion is magnified by increased
discharge of stormwater into the creeklines
which increases the volume of water carried by
these waterways. This contributes to
sedimentation and eutrophication further
downstream.
Bank erosion along Poison Gully
Local Biodiversity Strategy Page 20