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Review by Reed Noss of Tasmanian Forest Conservation Work Plan and Accompanying Reports
August 14, 2012
For this review I read in detail the Forest Conservation Work Plan and the Summary Report of
Conservation Values. I also skimmed the following reports and accompanying maps:
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ENGO Proposed Reserve Report
IVG Forest Conservation Report 1A (on comprehensiveness of existing conservation reserves)
IVG Forest Conservation Report 2A (on priority flora species on public forest)
IVG Forest Conservation Report 2B (on priority fauna species on public forest)
IVG Forest Conservation Report 3A (on refugia for ancient and relictual invertebrate fauna)
IVG Forest Conservation Report 3B (on palaeo-endemic plants)
IVG Forest Conservation Report 5A (on heritage value of ENGO-proposed reserves)
IVG Forest Conservation Report 7A (on all three species of Tasmanian marsupial carnivores)
Forest Conservation Work Plan
The general conclusion from my review is that the Work Plan has the appropriate scope for the problem
at hand and includes the necessary elements for conserving and restoring the multiple values of forest
ecosystems in Tasmania. I found the report well-researched and comprehensive. It is generally current
and defensible in its treatment of topics in ecology and conservation biology. I identified no significant
gaps in the report, although it is vague in its treatment of some concepts (e.g., source-sink population
dynamics). I have the following specific comments:
1. Pages 2-3. The concept of “High Conservation Value Forest” (HCV Forests) is discussed here. To
my knowledge, this terminology arose as a specific designation of the Forest Stewardship
Council (FSC) in the late 1990s. In 2000-01 I was a member of an FSC Advisory Panel, which
developed and refined specific criteria for designating and managing HCV Forests and applying
the precautionary principle. Unfortunately, the FSC abandoned this effort for unexplained
political reasons and, to my knowledge, has yet to issue specific guidance regarding the
designation and management of HCV Forests. I suggest that this history be considered in the
continuing discussion about HCV Forests in Tasmania, as well as the specific criteria developed
by the FSC Advisory Panel for designating these forests (assuming FSC will make these available).
This would help clear up some of the confusion identified in the report about what HCV Forests
actually are. That said, I agree with the statement (p. 3) that “when assessing the areas
proposed for reservation it will be important for the IVG to assess what conservation values they
possess and whether any values identified through the verification process are consistent with
principles and approaches commonly taken into account when considering areas for formal
reservation in Australia today.”
2. Pages 3-4. I agree with the “comprehensive information” sought through the specified “set of
analyses and the final technical report.”
3. Pages 7-9. I agree that it was appropriate to list the “Aichi Targets” from the Convention on
Biological Diversity and to state that these and other reservation targets “largely reflect the
outcomes of political deliberations and fall short of recommendations from scientific
studies…[which] suggest that 25-75% of a region must be managed with conservation of nature
as a primary objective to meet goals for conserving biodiversity.” The reference given (Noss et
al. 2011) should be Noss et al. (2012). It would be helpful to briefly state what factors determine
“how much is enough” in a particular region. These factors include physical heterogeneity
(topography, soils, etc.), beta diversity (species turnover along environmental gradients), level of
endemism, area requirements of wide-ranging species, the scale of the natural disturbance
regime, hydrologic connectivity, previous land use and reservation decisions (i.e., with some
features potentially “over-represented” and others “under-represented”), etc. Consideration of
these factors shows that the level of reservation needed to meet a given set of biological and
social goals will vary tremendously among regions (though, as stated, it usually falls in the range
of 25-75% except in heavily developed landscapes with little natural habitat remaining).
4. Page 10: I agree with the statement that “it is therefore important to understand that
percentage benchmarks are guides to minimum levels of reservation, constitute important
milestones, and are a ‘means’ and not ends in themselves.” I also accept the set of 10 values
listed as being “most relevant to the evaluation of the ENGO proposed conservation forest
areas.”
5. Page 12: The discussion of habitat quality and source-sink dynamics is appropriate but a bit too
simplistic. Source-sink is not a dichotomy but a continuous gradient of population growth rate.
So, whereas a population with an annual population multiplier (lambda) of 1.01 is technically a
source, and 0.99 is technically a sink, is this difference biologically meaningful? Habitat quality
also varies year to year, so a sink one year may be a source the following year. Studies have
shown that source-sink dynamics are not universal, and in some cases there is simply variance in
carrying capacity among sites and “balanced dispersal” among them. There can also be
“pseudosinks” of high habitat quality, but where mortality exceeds reproduction due to
crowding of individuals in these areas. Finally, because habitat relationships vary among species,
an area that is a source for one set of species may be a sink for another.
6. Page 13: It is stated that “areas which support higher natural rates of mean annual increment
and larger wood volumes can also support higher densities of forest wildlife due to a superior
and more consistent supply of habitat resources relative to other landscape locations.” I agree
that this is generally true for old-growth associated wildlife, but not for all animal or plant
species. Species respond differently to tree growth and wood volumes, with some preferring
more open or barren areas.
7. Pages 14-15: Regarding refugia, I agree that drought and fire are the two main processes here
for which many species will require refugia.
8. Page 16: It is stated that “there is now a clearly established scientific basis to the ecological
significance of large areas that have been minimally disturbed by human land use.” I agree, but
some reasons why such minimally disturbed (wilderness) areas are ecologically significant
should be stated. For example, wilderness areas are important refugia for species sensitive to
human presence, they maintain natural disturbance and hydrologic regimes (if large enough),
and they serve as unmanipulated control areas for comparison with managed landscapes (i.e.,
for adaptive management experiments).
9. Page 20: I generally agree, in this context, with the statement that the age structure of forests is
the condition most subject to degradation and likely to require restoration. Again, there will be
exceptions, as some species and processes are not highly sensitive to forest age structure. In
fact, naturally disturbed early successional forests are among the most biologically diverse and
depleted habitat types (e.g., see M.E. Swanson et al., 2010, “The forgotten stage of forest
succession: early-successional ecosystems on forest sites,” Frontiers in Ecology and the
Environment). In such forests, live tree volume is low and there is little age structure, but
biodiversity is high.
10. Page 22: It is an important point here that “Scientifically, the level of reservation required to
contribute to the protection of biodiversity and natural values is directly related to the success
or failure of production landscapes to contribute to nature conservation.” What goes on outside
reserves will largely determine the success of reserves and the persistence of species across the
landscape – unless reserves constitute the vast proportion of the landscape.
Summary Report of Conservation Values
In keeping with my instructions as a reviewer, I did not review this report in as much detail as the Forest
Conservation Work Plan, and my comments are few. I find this report of high quality.
1. Page 6: Figure 1, which shows the existing National Reserve System (NRS) and the 572,000 ha
proposed by ENGOs as additions to the system, vividly portrays how modest the ENGO proposal
really is. It also demonstrates that the proposed additions would help reduce fragmentation and
improve connectivity of the NRS, and would increase representation of features in the eastern
portion of Tasmania.
2. Page 7: It is stated that “there are around 28,000 ha where field inspection is required to
validate” the land cover within areas proposed for protection. I would guess that more area
than this would benefit from field inspection to verify land cover and conservation values.
3. Pages 9-11 and 52-53: I agree with all the “main conclusions from the heritage report” stated on
these pages. These are very well-founded and compelling conclusions.
4. Page 49: I agree that it is unfortunate that “appropriate data were unavailable for the IVG to
analyse the current distribution of forest wilderness.” I hope this can be corrected at some
point.
Conclusion
In conclusion, I am highly impressed by the work of the Independent Verification Group of the
Tasmanian Forest Agreement in producing these reports. The information is scientifically valid and in
line with current thinking in ecology and conservation biology. The reports demonstrate the general
validity and value of the ENGO proposal for increased protected forest areas in Tasmania.
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