The Focal Species Approach
Fauna and flora species are being lost from landscapes in
which their habitats are being cleared, fragmented and simplified.
To prevent further losses, it is necessary to determine the
composition, quantity and configuration of species that are
still present. Lambeck (1997) presented
an approach for defining the landscape attributes required
to meet the needs of biota, and also the management regimes
that should be applied to maintain them.
Lambeck's approach identifies a suite of sensitive fauna
species, each of which is used to define the configuration
and composition of habitats that must be present in the landscape
for that species to thrive. The species that is identifided
as being most sensitive to a threat in the landscape is termed
the 'focal' species. For example, the most area-limited species
is used to define the minimum areas required for various habitat
patches, and the most dispersal-limited species defines the
configuration of patches and the characteristics of connecting
vegetaion. It is assumed that because the most demanding species
are selected, a landscape designed and managed to meet their
needs will encompass the requirements of all other species
similarly threatened.
1. Identifying the threatening process/es:
There are a number of processes that can threaten the persistence
of plants and animals. The most immediate threats in the current
landscape include:
- Loss of habitat
- Isolation of habitat
- Rising saline water tables
- Predation by foxes and cats
- Inappropriate fire regimes
- Degradation of habitat by stock
- Weed invasion
- Problem native species
- Chemical and fertiliser drifts from adjoining farmland
Our research to date has has focussed on the threats of habitat
loss, isolation and degradation (e.g. loss of structural complexity).
2. Identify species that are at risk due to each threat:
To date we have found birds to be useful focal species because
many of them are sensitive to the threats of habitat loss
and degradation. Birds are useful because they are mobile
- they move across and use patches at the planning scale of
hectares (paddocks) and kilometres (properties). They are
also useful because they are relatively easy to survey, being
abundant and visible during the day. Species other than birds,
including plants, need to be analysed for the other threatening
processes in the landscape.
3. Rank species according to their sensitivity to each
threat:
We have found the small insectivorous birds, still found
in remnant woodlands, are particularly sensitive to loss of
habitat, degradation and some degree of isolation.
4. Determine the requirements of the most sensitive species:
We determine the habitat requirement of these woodland birds
through rapid surveys (3x20 min active searches) of 40-60
remnants across a range of sizes (1 ha - 100 + ha) and conditions.
5. Determine the level at which each threat must be managed
in order to protect the most sensitive species (development
of guidelines):
One means of examining the habitat requirements of these
birds is to plot their occurrences against key variables such
as remnant patch size, condition and isolation (see
report by Freudenberger 1999). An Excel spreadsheet
template has been created to assist in this graphical
interpretation of habitat requirements. (Please note: if
you experience difficulty downloading this Excel file as can
happen from older browsers, contact Dr David Freudenberger
for more information)
David.Freudenberger@csiro.au
6. Implementation of revegetation and management strategies
needed to meet the requirements of the most sensitive species:
The reports (1999 and 2001)
and poster by Freudenberger provide
examples of how this methodology has been used to develop
guidelines for a large NHT funded revegetation project facilitated
by Greening Australia. The publication
by Lambeck (1999) provides an example from Western Australia.
>> Some reports showing examples available to download.
7. Long-term monitoring to assess the success or failure
of these predictions of what is needed in the landscape to
conserve native biodiversity.
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David Freudenberger, October
1999: Guidelines for Enhancing Grassy Woodlands for
the Vegetation Investment Project. |
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David Freudenberger: The
Vegetation Investment Project: The Science and Action
of Conservation |
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David Freudenberger, June
2001: Bush for the Birds: Biodiversity enhancement
guidelines for the Saltshaker Project, Boorowa, NSW.
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Summary of this report:
CSIRO Sustainable Ecosystems was contracted by Greening Australia
to assist in the development of revegetation guidelines for
the Saltshaker Project in the Boorowa River catchment. The
project aims to improve the conservation of biodiversity,
reduce the risk of dryland salinity and increase water quality
by enhancing remnant vegetation and revegetating 2-3% of the
catchment.
The 'focal species approach' was used
to identify bird species that are sensitive to loss of habitat
area, simplification of habitat structure and increase in
habitat isolation. Bird surveys were conducted in 54 discrete
patches of woodland that varied in size, structural complexity
and isolation. A total of 115 species of birds were detected
during three 30-minutesurveys at each remnant during March
2001.The minimum was 16 woodland bird species, found in the
smallest and most simplified remnant, while up to 41 species
were found in large and structurally complex remnants. No
bird species was sensitive to just one threatening process.
Many woodland bird species were sensitive to at least three
threatening processes: habitat loss, habitat simplification,
and habitat isolation.
The Eastern Yellow Robin was selected as the focal species
for this catchment. It generally occurred in woodland patches
larger than 10 ha that were no more than 1.5 km from other
patches at least 10 ha in size. The woodland patches had at
least a moderate structural complexity, made up of a healthy
overstorey of Eucalypts with an understorey of regenerating
trees, shrubs, tussock grasses and fallen timber.
This focal species analysis identified the landscape configurations
and structural compositions of woodland patches that should,
as a minimum, provide occupiable habitat for the majority
of woodland birds that are known to be declining throughout
the region. It is assumed that these minima will also provide
habitat suitable for a wide range of other native species
of plants and animals that have similar or less demanding
habitat needs than the focal woodland bird. The analysis was
used to derive the following guidelines for the Saltshaker
Project
- As soon as possible, protect existing woodland remnants
from continuous grazing, by fencing them off. Give priority
to those remnants at least 10 ha in size, or those that
are within at least 1.5 km of existing remnants at least10
ha in size, or those that still have a structurally complex
understorey
- Where regeneration of native understorey( tussock grasses
and/or shrubs), or regeneration of trees is unlikely within
fenced remnants, then take steps to establish local-provenance
understorey grass or shrub species or trees.
- Enlarge (enhance) existing remnants to at least 10 ha
- Create linkages between protected and enhanced remnants
that are over 1.5 km away from other remnants at least 10
ha in size. At minimum, the linkages should consist of linear
plantings at least 25 m wide(5 rows), or 'stepping stones'
of block plantings at least 10 ha in size, or, ideally,
a combination of both.
- Create linkages at least 25 m wide between protected remnants
less than 1.5 km away from other remnants at least 10 ha
in size
- Create linkages at least 25 m wide between unprotected
(e.g. unfenced) remnants at least10 ha in size.
Implementation of these guidelines should provide useful
habitat for a wide range of biota that cannot otherwise persist
in the existing matrix of isolated trees, intensively grazed
pastures and crops that dominates the landscapes of the Boorowa
catchment. The Steering Committee of the Saltshaker Project
has integrated these biodiversity enhancement guidelines into
a transparent procedure for assessing a wide range of benefits
that on-ground works can generate for reducing dryland salinity,
improving water quality, increasing community participation,
and conserving biodiversity.
References Relating to the Focal Species Approach
Lambeck, R.J. (1997). Focal species: a multi-species umbrella
for nature conservation. Conservation Biology 11, 859.
Lambeck, R.J. (1999). Landscape planning for biodiversity
conservation in agricultural regions: a case study from the
wheatbelt of Western Australia. Biodiversity Technical Paper,
No.2. Environment Australia, Canberra.
Watson, J., Freudenberger, D. and Paull, D. (2001). An assessment
of the focal species approach for conserving birds in a variegated
landscape in south-eastern Australia. Conservation Biology
(in press).
Contacts
For more information contact David Freudenberger
David.Freudenberger@csiro.au
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