Fitzgerald biosphere recovery plan



Yüklə 0.74 Mb.
səhifə11/21
tarix21.08.2017
ölçüsü0.74 Mb.
1   ...   7   8   9   10   11   12   13   14   ...   21

5.1 Risk of the Threatening Processes in the Fitzgerald Biosphere


The risk of each of the threatening processes on the threatened species and ecological communities and the landscape units of the Fitzgerald Biosphere was determined to allow the recovery actions and management practices of this Plan to be focused where they are most needed.

Method of Determining Risk for Threatened Species and Ecological Communities


Analysis and ranking of the risk of threatening processes on the threatened species and ecological communities was undertaken using the Open Standards of the Practice of Conservation guidelines and the adaptive management software Miradi (CMP 2009). This involved assessing the risk of each of the threatening processes for each of the threatened species/communities over the next 10 years based on three criteria:

  • Scope (proportion of population expected to be affected),

  • Severity (the degree to which the population is expected to be affected), and

  • Irreversibility (degree to which the effects can be reversed).

Further details of this ranking process using Miradi is included in Appendix 6. The analysis and ranking of threats was based on best available knowledge and current understanding of impacts from individual threatening processes upon the threatened species and ecological communities.


The risk ratings for each of the threatened fauna, flora and ecological community to each of the threats in the Fitzgerald Biosphere are shown in Table 9 and Table. These ratings relate to the magnitude of the threat to the species/communities and its reversibility over the 10 year timeframe of this Plan.

Threatened Fauna


The risk ratings show that inappropriate fire regimes and predation by feral cats and foxes are the most significant threats to threatened fauna in the Biosphere, followed by loss of habitat, fragmentation and degradation, stochastic events and climate change (Table 9).
Phytophthora cinnamomi is ranked as a low threat for most of the threatened fauna species, except the Dibbler for which it is a medium threat as it occurs in habitat dominated by susceptible flora species. P. cinnamomi is not considered a threat to the Red-tailed Phascogale or Numbat. However, P. cinnamomi is considered a very significant threat in the Biosphere due to its significant impact to biodiversity overall and because it cannot be eradicated.
Overall these risk ratings show that all the threatened fauna species were ranked as high to very high risk in the Fitzgerald Biosphere, except the Chuditch and the Numbat which have a medium rating. The Western Ground Parrot is the most at risk due to its small population size.
Table 9: Risk ratings for each of the threatened fauna species to each of the most significant threats in the Fitzgerald Biosphere over then next 10 years, as determined using Miradi (CMP 2009). These ratings are based on three criteria: Scope, Severity and Irreversibility (Appendix 6). Blank = not considered a significant threat to that species.

Threats
Species

Invasive fauna

Inappropriate fire regimes

Phytophthora cinnamomi

Cats & foxes

Weeds

Salinisation/ altered hydrology

Climate change

Loss & fragmentation of habitat

Stochastic (chance) events

Summary Risk Rating

Carnaby's
B-Cockatoo


High

Medium

Low




Low

Low

Low

High

Medium

High

Chuditch

Low

Medium

Low

High




Low

Low

Low

Low

Medium

Red Tailed Phascogale

Low

High




High

Low

Low

Medium

Low

Low

High

Dibbler




High

Medium

High




Low

Medium

Low

Low

High

Heath Mouse

Low

High

Low

High




Low

Medium

Low

Low

High

Malleefowl

Medium

Medium

Low

High

Low

Medium

High

High

Low

High

Numbat

Low

Medium




High




Low

Medium

Low

Medium

Medium

Western Bristlebird




High

Low

High

Low




High

Low

High

High

W. Ground Parrot

Low

Very High

Low

Very High

Low




High

Medium

High

Very High

Summary Risk Rating

Medium

Very High

Low

Very High

Low

Low

High

High

High





Threatened Flora and Ecological Communities


The risk ratings show that inappropriate fire and climate change are the most significant threats to threatened flora and the ecological community in the Biosphere (Table 10). Climate change is a significant threat for many of the flora species due to small population sizes, and that they rely on specific habitats (e.g. the tops of the hills of the Barren Range) that are likely to be highly impacted by any changes in temperature or rainfall.
Phytophthora cinnamomi is ranked as a low to high threat and is not a threat for nine of the threatened flora species. These rankings were made with the assumption that P. cinnamomi will not become widespread in the Biosphere in the next 10 years, but because it cannot be eradicated from where it does spread, it is considered a very significant threat in the Biosphere.
The risk of the threatening processes in the Fitzgerald Biosphere are unknown for Conostylis lepidospermiodes and Lepidium aschersonii, as these species have not been seen in the Fitzgerald Biosphere in recent years (Appendix 2).
Table10: Risk ratings for each of the threatened flora species and the ecological community to each of the most significant threatening processes in the Fitzgerald Biosphere over then next 10 years, as determined using Miradi (CMP 2009). These ratings are based on three criteria: Scope, Severity and Irreversibility (Appendix 6). Blank = not considered a significant threat.

Threats

Species/

Communities

Invasive fauna

Inappropriate fire regimes

Phytophthora cinnamomi

Weeds

Salinisation/ altered hydrology

Climate change

Loss & fragmentation of habitat

Stochastic (chance) events

Summary Risk Rating

Acacia rhamphophylla




High

Low

Low

Low

Medium

Medium

High

High

Adenanthos dobagii




Low

High







Medium




Low

Medium

Adenanthos ellipticus




Low

Medium







High




Low

Medium

Anigozanthos bicolor subsp. minor

Medium

Medium

Low

Low

Low

Low

Medium

Low

Medium

Beyeria cockertonii




Low

Low




Medium

Medium

Medium

Medium

Medium

Boronia clavata

Low

Low




Medium

Low

Medium

Medium

Low

Medium

Conostylis lepidospermiodes

Not known

Not known

Not known

Not known

Not known

Not known

Not known

Not known

Not known

Caladenia bryceana subsp. bryceana

Low

Medium




Medium




Medium

Medium

High

Medium

Coopernookia georgei




Low

Low







High




Medium

Medium

Daviesia megacalyx




Low

Medium







Medium

Low

Medium

Medium

Daviesia obovata




Low

Medium







High




Medium

Medium

Eremophila denticulata subsp. denticulata

Low

Low




Low




Medium

Low

Low

Low

Eremophila subteretifolia




Low







Medium

Medium




Low

Medium

Eucalyptus burdettiana




Low

Low







High




Low

Medium

Eucalyptus coronata




Low

Low







High




Low

Medium

Eucalyptus nutans




High










High




Low

High

Eucalyptus purpurata




High







High

Medium

High

Low

High

Grevillea infundibularis




Low

Medium







Medium




Low

Medium

Hibbertia abyssa




Low

Medium

Low

Medium

Medium

High

Low

Medium

Kunzea similis subsp. similis




Very High

High







High




High

Very High

Kunzea similis subsp. mediterranea




Low

High




High

Medium

High

Low

High

Lepidium aschersonii

Not known

Not known

Not known

Not known

Not known

Not known

Not known

Not known

Not known

Marianthus mollis




Low

Low







Low

Low

Low

Low

Myoporum cordifolium




Low










Low




Low

Low

Ricinocarpos trichophorus




Low










Low




Low

Low

Stylidium galioides




Low

Low







High




Medium

Medium

Thelymitra psammophila

Low

Low




Medium

Low

Medium

Low

Low

Medium

Verticordia crebra




Low

Low







Medium




Medium

Medium

Verticordia helichrysantha




Medium

Medium







High




Medium

Medium

Verticordia pityrhops




Very High

High







High




High

Very High

Eucalyptus acies mallee heath




High

High







Medium




High

High

Summary Risk Rating

Low

Very High

High

Medium

High

Very High

High

High





Landscape Units


Susceptibility of the Landscape Units of the Fitzgerald Biosphere to significant threats are summarised in Table11. Risk of the threats were not ranked using Miradi due to the complexity of the Landscape Units. Each Landscape Unit responds differently to threatening processes due to different physical characteristics and these differences need to be understood when considering threat abatement.

Table11: The most significant threatening processes and susceptibility to these threats of each of the Landscape Units of the Fitzgerald Biosphere.




Landscape Units

Threats specific to Landscape Unit

(including current level of threat within landscape units plus potential threats based on specific susceptibility of the unit to threat)



Albany Fraser Coastal

Stable system - sensitive to frequent disturbance

  • Climate change (species at edge of range, restricted, endemic)

  • Phytophthora (highly susceptible flora and vegetation communities)

Depositional Dynamics

Highly dynamic system - adapted to frequent ground disturbance

  • Weed infestation

  • Salinisation

  • Erosion

  • Siltation of waterways

Depositional Eocene

Relatively dynamic system - resilient to disturbance to some degree

  • Weed infestation

  • Frequent fire (in particular the mallet and moort communities)

Esperance Sandplain

Relatively stable system - sensitive to frequent disturbance

  • Phytophthora (highly susceptible Banksia communities)

  • Climate change (species at edge of range)

  • Fragmentation of habitat

  • Salinisation (saline and freshwater lake systems)

  • Development and recreation impacts

  • Insecure tenure

Greenstone

Patchily stable system - sensitive to frequent disturbance

  • Inappropriate fire (many fire sensitive vegetation communities)

  • Phytophthora (susceptible proteaceous heath).

  • Mining activity (clearing, changed hydrology)

  • Climate change- high levels of endemism due to unique geology, species at ends of range and relictual species (e.g. invertebrates).

  • Invasive fauna (feral bees, rabbits)

  • Recreation impacts

  • Insecure tenure

Marine Plain

Relatively stable system - sensitive to frequent disturbance

  • Inappropriate fire (mallet and moort vegetation communities)

  • Phytophthora (highly susceptible species and communities)

  • Invasive fauna (rabbits in deep sands, feral bees in breakaways)

  • Climate change- endemic communities, spongelite breakaways (i.e. isolated communities)

  • Weed invasion in deep sands

Quartzite Range

Relatively stable system - sensitive to frequent disturbance

  • Inappropriate fire (relictual species that require long unburnt habitat)

  • Phytophthora (highly susceptible communities: mountain thicket, heath and mallee-heath)

  • Climate change (refugial habitats and relictual species)

Yilgarn Block East

Stable system - sensitive to frequent disturbance

  • Susceptible to disturbance (slow regeneration, fragile biological soil crusts, nutrient poor)

  • Salinisation (susceptible habitats (salt lakes, low-lying woodlands)

  • Phytophthora (susceptible species and habitats)

  • Fragmentation of habitat

  • Highly erodible

  • Inappropriate fire (woodland communities)



1   ...   7   8   9   10   11   12   13   14   ...   21


Verilənlər bazası müəlliflik hüququ ilə müdafiə olunur ©azkurs.org 2016
rəhbərliyinə müraciət

    Ana səhifə