Biodiversity outcomes from plantation expansion into
agricultural landscapes
Students
Tanya Bailey (PhD
student, University of Tasmania) - catch up on Tanya's research on
tree decline and recruitment in the Tasmanian midlands in a
separate
article in this issue of Biobuzz.
Himlal Baral (PhD
student, University of Melbourne) commenced his studies in 2008 and
is currently collecting data. He is using geographic information
system (GIS) technology as a tool for mapping biodiversity and
other ecosystem services within sub-catchment G8 in the Lower
Glenelg Basin of the Green Triangle. The current and potential
impacts of silviculture and management practices on habitat and
species distributions will be analysed using spatial tools. Himlal
will also explore different land use and climate change scenarios
and their potential impacts on habitats and species’
distributions. Himlal is currently analysing numerous data
and writing various conference and journal papers. One paper
has been accepted for the
IFA biennial conference that is going to be held in Caloundra
in September (2009); this work will be published in a volume of
refereed conference proceedings:
Baral H, Kasel S, Keenan R, Fox J, and Stork N (2009) GIS-based
classification, mapping and valuation of ecosystem services in
production landscapes: a case study of Green Triangle region of
south-eastern Australia. Proceedings of the Biennial Conference of
the Institute of Foresters of Australia, Caloundra, 2009.
Katarzyna (Kasia)
Bialkowski (PhD student, Murdoch University) is studying how
microbial activity and soil health vary among different land uses
(native bush, remnant vegetation, pasture, blue gum
plantations) and also with the condition of native vegetation
remnants and different restoration treatments. She completed the
design and optimisation of a series of laboratory tests for
analysing soil microbial activity in late 2008. This was a
time-consuming process involving more than 20 tests and several
lengthy experiments. Exploratory sampling and analysis of soils
under different land uses took place in late spring 2008 and
post-treatment sampling from a pilot restoration field trial was
conducted in late summer 2008. A preliminary laboratory experiment
to test the influence of soil amendments on soil microbial
activities took place in early autumn 2009. Collation of data and
statistical analyses of the datasets from field and laboratory
tests are in progress.
Mayumi Knight (PhD
student, University of Melbourne) is studying the relative roles of
remnant vegetation patches embedded in blue gum plantations, pine
plantations and farmland in supporting bird and bat biodiversity.
She recently completed her PhD confirmation and has already
collected half of her bird and bat data. The first season's surveys
involved four major field trips to assess bird communities across a
total of 60 sites and bats at around 45 sites (although bat surveys
were limited by fire ban days, and cool snaps later in the season).
Preliminary results suggest no major differences in bird species
richness, bird species diversity (Shannon and Simpson), or total
bird abundance across sites. Analyses on the abundances of specific
species, however, do reveal some differences. For example the
Welcome Swallow was significantly more abundant among remnant
vegetation surrounded by pasture than that surrounded by blue gums
or pines. Many more analyses are required to tease apart the
intricacies of subtle differences in community structure between
remnant patch types. The field exercise will start up again at the
end of the year. Mayumi will soon commence an analysis of a library
of bat echolocation calls that she amassed this field season
(roughly two nights worth of recorded data per site to sift
through). Another off-season task is to design a habitat structure
survey to apply to her sites, and possibly a small-scale study to
quantify the use of the different matrix types themselves by bird
and bat communities.
Chela Powell (PhD
student, University of Melbourne) - now moving steadily towards the
culmination of her PhD on invertebrate assemblages in remnant
vegetation, you can read about Chela's research progress in a
separate
article in this issue of Biobuzz.
Kate Taylor (also with
CRC for Forestry Project 1.2; PhD student, Murdoch University) is
studying the origin and establishment of Mycosphaerella
cryptica and M. nubilosa in Western Australian
plantations and native forests. Kate is conducting a
molecular analysis of extensive collections from throughout
southern Australia to construct a pattern for movements of
Mycosphaerella within Australia and into WA.
Tom Wright (PhD student,
University of Melbourne) is studying the effect of microclimatic
and physiological gradients at remnant vegetation-plantation edges
and remnant vegetation-agricultural edges within the green triangle
region. He has completed his fieldwork, is now in the process of
writing up his results and expects to submit his thesis later this
year. Tom has found that plantations adjacent to remnant vegetation
provide shelter from sun and wind in winter, reducing plant water
stress for understorey vegetation. However, in summer, the
overstorey vegetation in remnants at plantation edges was actually
more water stressed, suggesting competition for water resources
with the adjacent blue gums. Thus, plantations appear to have both
positive and negative effects on adjacent native vegetation owing
to complex interactions with seasons and edge types.
Belinda Browning
(MSc, University of Tasmania) recently submitted her Masters
thesis. Her study considers how bryophyte communities persist
on harvest residue and on pre-harvest legacy coarse woody debris in
forests regenerating after the first clearfell, burn and sow
harvesting rotation. Further details will appear in a later issue
of Biobuzz … (Bindy is also associated with subproject
4.2.3).
Affiliated students
Bryony Horton (PhD student,
University of Tasmania) is studying the mycorrhizal fungal
community of declining Eucalyptus delgatensis forest in
Tasmania. Bryony has conducted some preliminary analyses which show
that of the 283 species of ectomycorrhizal fungi within her study
plots, 191 species were found as fungal fruiting bodies (some
examples of which are shown, left) and 134 species were found on
eucalypt root tips. Only 42 species were found as both fruiting
bodies and as ectomycorrhizal root tips. The mycorrhizal community
was dominated by the genus Cortinarius. Interestingly the
mycorrhizal community differed significantly between forest with a
dry sclerophyll understorey (characterised by more recent fire) and
forest with a rainforest understorey (characterised by the long
absence of fire). Ectomycorrhizal community composition was also
found to differ in sites where eucalypts were moderately affected
by dieback and sites where there was severe dieback.
Cheryl O’Dwyer
(part-time PhD student, University of Melbourne) is making solid
progress writing up her PhD and is due to submit her thesis in a
few months' time. She has been investigating how habitat quality
and fragmentation affect insect assemblages inhabiting Grey Box
grassy woodlands in northern Victoria. Cheryl has found that the
quality of habitat, as measured by habitat hectares or the state
transition model, is strongly correlated with insect species
richness. Interestingly, the effect of habitat quality on insect
diversity is much stronger than that of fragment size. Cheryl
will be presenting some of her findings at "DARWIN 200:
Evolution and Biodiversity" (The Combined Australian
Entomological Society’s 40th AGM & Scientific Conference
/ Society of Australian Systematic Biologists / 9th Invertebrate
Biodiversity & Conservation Conference) being held in Darwin
from 25th to 28th September, 2009.
Jennifer Sanger (University of
Tasmania) has completed her Honours degree. She examined whether
increasing drought frequency was a major driver in the decline of
the endangered tree species Eucalyptus gunnii (pictured
left) in the Central Plateau region of Tasmania. Specifically she
was looking at whether climate change has led to a shift in the
regeneration niche of E. gunnii subsp. divaricata
and if changes in stand dominance are occurring where the
subspecies co-occurs with E. pauciflora. An assessment of
the micro-site characteristics of E. gunnii between young
and adult trees showed that successful regeneration was restricted
to deeper soils (65±3 cm) within slight micro-site
depressions. In contrast the poor regeneration and adult cohort
occurred on steeper, concave micro-sites with shallow soil
(39±2 cm and 47±3 cm, respectively). This shift in
the regeneration niche to micro-sites with greater water holding
capacity may be linked to the 25% reduction in average annual
summer/autumn rainfall over the last 50 years. On the slopes
surrounding waterlogged depressions where E. gunnii and
E. pauciflora co-occurred, juvenile E. pauciflora
were significantly more abundant than juvenile E. gunnii,
compared to the relative proportions in the large adult cohort.
This suggests a shift in stand dominance may be occurring.
Biobuzz issue nine, August 2009
