Barker, P., Wardlaw Tj, et al. (1996). "Selection and design of

Phytophthora management areas for the conservation of threatened flora in

Tasmania." Biological Conservation 76(2): 187-193.

In Tasmania Phytophthora cinnamomi can cause serious disease in heaths,

dry sclerophyll forests, moorlands and disturbed rain forests growing below

600 m and receiving more than 600 mm rainfall annually. Before the current

research 136 native plant species were known to be hosts for P. cinnamomi.

Very few of these plant species are considered threatened by its

activities. However, susceptible rare and threatened plants are at the

greatest risk. Management areas were selected and designed for the purpose

of safeguarding 44 species (many of them woody) that appear on state and

national lists of rare and threatened plants and are susceptible to and

potentially at risk from P. cinnamomi. The selection process and criteria

used for selecting management areas are described. Of the 101 areas

surveyed 74 were selected based on their diversity and the aim of selecting

3 management areas, when possible, for each species. The 61 areas finally

selected were based on landscape management criteria as well as species

criteria; they contained all 44 target species. There were 109 inclusions

of target species in the 61 management areas selected out of a possible 136

in the original 101 areas.

Kile, G., J. Packham, et al. (1989). "Myrtle wilt and its possible

management in association with human disturbance of rainforest in

Tasmania." Special issue: Workshop on forest health in the South Pacific,

Rotorua, 30 31 May and 1 June 1989 19(2-3): 256-264.

Chalara australis is a lethal primary pathogen of Nothofagus cunninghamii

(myrtle) in Tasmanian rain forests. It is a major cause of gaps in

myrtle-dominated stands but mortality is often most severe in rain forest

subject to human disturbance. Potential strategies for minimizing the

disease in areas of disturbed rain forest are discussed.

Podger, F. and M. Brown (1989). "Vegetation damage caused by Phytophthora

cinnamomi on disturbed sites in temperate rainforest in western Tasmania."

Australian Journal of Botany 37(6): 443-480.

P. cinnamomi was isolated directly from 558 diseased plants of 39 species,

including 1 fern, 4 graminoids and 34 woody dicotyledons, all indigenous to

the cool temperate rain forest of Tasmania. Pathogenicity was proved by

greenhouse tests (20 spp.) and by field inoculation at two sites (19 spp.).

Of the 142 species in the rain forest flora, 69 were rated for the

susceptibility of field populations: 30% were highly susceptible and less

than 5% highly resistant. High proportions of susceptible species occurred

in Epacridaceae, Eucryphiaceae and Proteaceae. All 93 isolates tested were

the common A2 mating type. The fungus was consistently associated with

disease at 47 survey sites. Diseased plants were widely but patchily

distributed along exposed road and track edges within unburned rain forest

and in recently burned rain forest. The fungus was not recovered from soil

samples taken beneath healthy roadside regeneration, beneath undisturbed

rain forest or above 900 m alt. The disease has the characteristics of

attack by a recent invader and appears to be dependent upon disturbance

which increases soil temp. above 15ƒC, the lower threshold for infection by

P. cinnamomi. Post-fire recovery of forest canopy is expected to allow

re-establishment from external sources of seed of those susceptible species

which are both efficiently dispersed and tolerant of shade. Species lacking

such characteristics are at risk of local elimination but no single rain

forest species appears to be under threat of extinction from this pathogen.

Podger, F., C. Palzer, et al. (1990). "A guide to the Tasmanian

distribution of Phytophthora cinnamomi and its effects on native

vegetation." Tasforests 2(1): 13-20.

A map of the distribution of Phytophthora cinnamomi in Tasmania and a list

of 136 Tasmanian native plants which have been recorded as hosts are

presented. Guidelines for recognition of infested areasare given.

Wilkinson, G., M. Battaglia, et al. (1993). "Silvicultural use and effects

of fire." Technical Bulletin Native Forest Silviculture, Forestry

Commission, Tasmania No. 11, 60 pp.; 11 pp. of ref. PUBLISHER

INFORMATION(Forestry Commission): Tasmamia.

A discussion is presented in 3 parts on the effects of fire on the

silvicultural management of Tasmania's native forests which are mostly

eucalypt (Eucalyptus spp.) forests. Part A provides guidelines for the

silvicultural use of fire for site preparation and fuel reduction and for

the management of forests damaged by fire. Part B contains a summary of the

ecological effects of fire in Tasmania's forests. Part C is a comprehensive

literature review (on which parts A and B are based) and includes sections

on (i) prehistory of fire in Tasmania, (ii) eucalypt fire ecology, (iii)

ecological models of vegetation, fire and time, and (iv) effects of fire on

soils, water, air, vegetation and fauna.

Fensham, R. (1994). "Phytophagous insect-woody sprout interactions in

tropical eucalypt forest. I. Insect herbivory." Australian Journal of

Ecology 19(2): 178-188.

Foliar insect damage was assessed on woody sprouts in the ground layer of

two tropical eucalypt forest (dominated by Eucalyptus miniata or E.

latifolia and E. confertiflora) communities on Melville Island, Northern

Territory, from October 1986 to June 1988. Insect damage levels ranged from

7.8 to 43.2%. Of 8 common tree species, Eucalyptus confertiflora was

damaged most by insects and Buchanania obovata and Terminalia ferdinandiana

suffered least damage. Seasonal trends in insect damage were not consistent

between plant species and were not always consistent between vegetation

types for a particular plant species. The results of this study are not

consistent with hypotheses suggesting that insect grazing is a critical

determinant of tree species dominance or woody sprout dormancy.

Wilkinson, G. and W. Neilsen (1995). "Implications of early browsing damage

on the long term productivity of eucalypt forests." Forest Ecology and

Management 74(1-3): 117-124.

Seedlings of Eucalyptus nitens (Deane et Maiden) and Eucalyptus regnans F.

Muell. were artificially defoliated at various times during their first

growing season in order to simulate the effects of animal browsing. Results

after 7 years indicated that there was no long term effect on the survival

and growth of seedlings that were subjected to the removal of growing tips

in the first spring and autumn following planting. The loss of half of the

crown in autumn resulted in lower survival than for unbrowsed seedlings but

the better growth rate of the surviving seedlings resulted in no loss of

total volume production. However, seedlings subjected to the loss of half

of the crown in spring produced 25% less total volume growth than unbrowsed

seedlings. The complete removal of the crown resulted in long term volume

losses of 71-97% as a result of very low survival and poor growth rates.

The poor growth of heavily browsed seedlings was attributed to their

failure to achieve dominance over the competing vegetation. Overall, the

severity of defoliation had a greater effect on survival and growth than

the timing of treatment, although browsing in autumn resulted in higher

mortality than in spring. The results confirmed the need for eucalypt

seedlings to be protected against severe browsing damage in order to

achieve site occupancy and full growth potential.Keywords: Browsing damage;

Productivity; Eucalypt forest; Eucalyptus spp.

Whitham, T. G., P. A. Morrow, et al. (1994). "Plant hybrid zones as centers

of biodiversity: The herbivore community of two endemic Tasmanian

eucalypts." OECOLOGIA 1994 vol no. 4: pp.

We found the hybrid zone between Eucalyptus amygdalina and Eucalyptus

risdonii to be a center of insect and fungal species richness and

abundance. Of 40 taxa examined, 73% were significantly more abundant in the

hybrid zone than in pure zones, 25% showed no significant differences, and

2% were most abundant on a pure host species. The average hybrid tree

supported 53%more insect and fungal species, and relative abundances were,

on average, 4 times greater on hybrids than on either eucalypt species

growing in pure stands. Hybrids may act as refugia for rare species: 5 of

40 species were largely restricted to the hybrid zone. Also, 50% of the

species coexisted only in the hybrid zone, making for unique species

assemblages. Although hybrids support more species and greater abundances,

all hybrids are not equal: 68% of the 40 taxa examined were significantly

more abundant on one hybrid phenotype than another. While herbivore

concentrations on F1 type intermediates were rare, concentrations were

common on phenotypes resembling backcrosses either to E. amygdalina or E.

risdonii. For specialist herbivores, the hybrid phenotype most heavily

utilized appears to be determined by its phenotypic affinity to its host

species. Generalists exhibit an overall greater abundance on hybrids, but

are less likely to utilize one hybrid phenotype over another. Mechanistic

explanations for these distributions are numerous and probably species

specific, but are likely to include: increased genetic susceptibility of

hybrids due to hybrid breakdown; increase in the hybrid zone resulting in

greater plant susceptibility; and a greater diversity of resources in the

hybrid zone which could support more species. Seed capsule production by

hybrids and their parental species is negatively correlated with herbivory.

However, it is difficult to determine whether herbivores cause this pattern

as hybrids may have inherently lower sexual reproduction. Laws enacted to

protect rare and endangered species do not include hybrids. We argue that a

re-examination of our current "hybrid policy" is warranted. Plant hybrid

zones are centers of plant evolution and speciation, sources of

economically important plants and potential biocontrol agents, and, as our

study suggests, also provide essential habitats for phytophagous

communities.

Potts, B. M. (1985). "Variation in the Eucalyptus gunnii- archeri complex.

111. Reciprocal transplant trials." Australian Journal of Botany 33:

687-704.

Potts, B. M. and W. D. Jackson (1986). Evolutionary processes in the

Tasmanian high altitude eucalypts. Flora and Fauna of Alpine Australasia.

Ages and Origins. B. A. Barlow. Melbourne, CSIRO: 511-527.