Historic data is crucial in answering our questions about what will likely happen in the future with the woodland and forest systems in Australia. Changes in the past have given us indications of what might happen in the future. However, there is need for more investigation to find out how (and if) the projected changes in climate impact on woodland and forest system functioning. For the southwest of Australia, it is predicted that temperatures will rise and rainfall will continue to decrease over time. Prolonged droughts are also projected to occur more frequently. Understanding how these changes will (possibly) have a flow-on effect on woodland and forest functioning is crucial for making informed decisions in the future.

The ultimate aim of my/our work is therefore to predict what will happen in the future with the native woodlands and forests in southwest Australia in terms of health and development with the projected changes in climate. This work will contribute to informing us on how to deal with these possible changes in the future.

For this project, the biggest challenge is to acquire time series data spanning back 10-50 years or more that have consistently recorded (ecological useful) variables at one geographical location. For climate variables (i.e. temperature and rainfall) there are relatively good long-term historic data series available. However, long term historic datasets that tell us something about the vegetation and fauna in relation to, for instance, their health, are much harder to come by. Finding these data sources is one of the keys to the ultimate success of this project.

So what kind of “useful” data are we after? Well, anything that focussed on monitoring elements within the same woodland or forest system over time. You could think of annual flowering times of one or more tree species, or emergence of the first flowers of a particular plant species in the understorey. Or maybe the first sighting of a certain butterfly or other pollinator that was recorded over several years. Or measurements related to soil moisture or rainfall combined with growth measurements of a certain plant or tree during the last couple of decades or so.

I would like to invite everybody who knows of this kind of data, either gathered by him/herself or somebody they know, to contact me (Niels Brouwers; n.brouwers@murdoch.edu.au). I am further keen to hear your perspectives and suggestions on this project. How would you tackle these issues? I am looking forward to your responses!

As the new fauna postdoc within the Centre, my research will be looking at the role of fauna in maintaining ecosystem health.  Sounds intriguing, doesn’t it?  I’ve been pondering just how I will tackle this broad idea over the last couple of months.    In one of the first meetings I attended, I asked what were the Centre’s “Big Picture Questions”.  As the Centre’s vision for research is to ensure healthy woodland and forest ecosystems, the following big picture questions were suggested: How do woodland systems work when they are healthy? What happens when they go wrong? How do we fix it?

So, how do fauna relate to these questions?  Fauna are a very important component of ecosystems.  For example, fauna are often pollinators of plant species, and the abundance and species of herbivores can change plant species richness as well as ecosystem processes.  Fauna are often used to monitor the ‘health’ of an ecosystem. For instance, the health of freshwater systems is often measured by the number and diversity of native and non-native invertebrate fauna and fish.

The impact of ecosystem processes, such as fire, can also alter the “ecosystem health” of a forest or woodland.  Some recent work I’ve been doing this year with the Department of Environment and Conservation has examined the productivity (in terms of fruit produced) of Banksia attenuata and B. menziesii in different time-since-last-fire habitat.  What does this have to do with fauna I hear you say??  Well, Carnaby’s Black-Cockatoo is an endangered cockatoo that feeds on Banksia of the Swan Coastal Plain, and the loss of food resources has been attributed to their decline.   By examining the productivity of Banksias in different fire-aged habitat, we can provide information to land managers on the range of fire-free intervals that will result in the greatest amount of food resources for Carnaby’s.

For my future work with the Centre, I’m particularly interested in how predation affects fauna assemblages.  Carnivores can regulate the population abundance of other fauna, and without native predators, or with the introduction of non-native predators, changes to the ecosystem health can occur.  For example, when wolves became extinct in Yellowstone National Park, their prey (elk) altered their browsing behaviour to an extent that nearly led to the localised extinction of two cottonwood tree species.   In a move towards restoring the ecology of this ecosystem, wolves have been reintroduced into Yellowstone National Park.  In SWWA, introduced foxes have been implicated in the dramatic decline of numerous native mammals.  I’d like to look at how the loss of native mammals from SWWA may have impacted ecosystem health. In addition, I’m interested in examining how the removal of foxes may change native faunal assemblages, as well as the impact of other meso-predators on fauna in declining and healthy woodlands.

Of course, there are many other projects that I’d like to look at too! In order to answer the Big Picture Questions there are a number of issues that researchers in the Centre need to understand.  Ideally, we need to know how faunal assemblages are composed and operate in health ecosystems, what happens to the fauna when the ecosystem health declines, and how fauna can contribute towards fixing a declining ecosystem.  Looks like we’ve got our work cut out for us!

(Click the image first and see what happens)

Building computer simulations involves deciding which aspects of a real-world system are most important, and then representing them ‘in silico’ by using mathematical equations or computer-coded algorithms and rules. Models cannot include every part of reality, and thus must always simplify reality – in fact this is what makes them useful! A model that includes too much becomes just as difficult to understand and analyse as the real world. For example, if we want to model the effect of climate change on the growth of a tree in South-Western Australia, we don’t represent a butterfly flapping its wings in Brazil in our model! Modelling thus requires decisions about which parts of the world should be represented in the model, and about exactly how to represent them. These decisions will always involves trade-offs between desirable objectives, such as realism, precision, explanatory value, simplicity and generality.

Models can be made for various purposes. Models can be created to help clarify or understand, for purposes of comparison, prediction or management, or in order to educate and communicate ideas, or even to convince people. They can simply help visualise ideas or results, or aim for accurate prediction in a range of conditions, or act as a theoretical framework for experimental investigations. They can save time and money by helping to focus experimental resources, identify knowledge gaps, and synthesise knowledge. Sometimes, if experiments are impossible, too dangerous, too expensive, or would take too long, then modelling is the only option for predicting what will happen under different scenarios. Clearly identifying the purpose of a model is essential for guiding decisions about what to represent in a model and at what level of detail.

In particular, computer simulation modelling may be able to help us better understand, predict and manage the health of forests and woodland ecosystems in the face of changing climates. By modelling important ecological processes happening across a spatially mixed agricultural landscape with bushland fragments, we might be able to predict the effects of different restoration strategies on biodiversity and agricultural production, and thus choose the best strategies. By representing trees as individuals growing in groups including different species, we can predict the way that they deal with reduced rainfall, while taking into account different species’ strategies for water use and individual variability, and explore possible management options, such as burning or thinning. And by modelling the important ecological processes operating across larger scales, such as local extinction and re-colonisation, gene flow, seed dispersal, competition and evolution, we can predict how the range of different species will change with climate change, and whether restoration or assisted migration can help threatened species persist. In all these situations, experimental data is essential but full experimental analysis is impossible, due to the costs and scales involved, and so building and playing with virtual worlds provides an opportunity to help understand and benefit our real one.

What does our Research Centre on “Climate Change Woodlands and Forest Health” have to do with the federal governments’ latest decisions on the abandonment of the newest version of an Australian Emissions Trading Scheme?

About a fortnight ago, PM Rudd put the plans for a national “Carbon Pollution Reduction Scheme” (CPRS) into the deep freeze. Protests followed. Had the CPRS, the Australian version of an Emissions Trading Scheme, been the provisional last hope to show that signing the Kyoto protocol in 2007 had been more than a symbolic political act? In a recent analysis of Australian climate politics, Kyoto itself is presented as “a veil behind which inaction on climate change can be hidden” (Howarth and Foxall, 2010). Prior to Kyoto, Australia had contributed to the veil by negotiating the ‘Australia clause’, i.e. an inclusion of emissions from land clearing in the computation of emissions in the base year 1990, causing a situation where actual CO2 emissions, coming mainly from the industry, energy and transport sectors, have been able to grow drastically as compared with the 1990 baseline. In the meantime, Australia could report in Copenhagen that it was relatively ‘on track’ as regards its reduction target of 108% in 2012. And now even the main chosen mechanism to ‘cap and trade’ emissions in the future is in the deep freeze.

Let’s for a moment look at this latest development from a restoration ecology point of view. The decision could be perceived as bad news, for a pricing and trading system for carbon could have brought in more financial resources for revegetation. Have these resources now landed in the proverbial deep freeze as well? How bad is that? One serious risk of the CPRS was that ‘reveg monocultures’ for carbon sequestration would become more lucrative than revegetation for a combined set of objectives such as biodiversity, salinity control, wind erosion or providing connections for fauna in agricultural areas. So perhaps it is not all bad… And what does the decision mean for our research? Has it become less relevant to investigate how revegetation on degraded parts of private and public land, is most likely to succeed? We would say the answer is “no, on the contrary”. In our research on volunteering in ecological restoration, we have seen various private landowners (farmers and non farmers) interested and/or involved in establishing biodiverse plantings on their land – with or without a CPRS. Now that the national government has delayed renegotiations of new versions of trading mechanisms, local revegetation trials and activities should still progress, investigating how in altered climatic conditions, different objectives of revegetation, including carbon sequestration, can be successfully combined. While the national government will be temporarily absent on this, it is even more important that local and regional policy makers, landowners and researchers start working together more on finding ways to address these challenges. What do you think?

Colin Spencer: Hello fellow tuart watchers

I have been closely observing Tuart trees in and around Bunbury. Most of them are producing prolific amounts of flower bud. There is an amazing litter of operculums under some trees.

I was expecting a spectacular mass of flowers, much like that seen in marris, jarrahs, red flowering gums etc. However, I was quite disappointed as it seems that when the bud cap drop, a very short amount of time elapses before the cream coloured stamens are either blown away by rain, or wind or just shrivel up and disappear. Some bud caps clasp the stamens so tightly that they also pull them off.

This very short flowering time, and perhaps even absence of actual flowers, stamens etc. makes me think whether there is much pollination of the flowers occuring. It seems that many of the tuarts around Bunbury have lost their bud caps and there hasn’t really been a flowering event? It will be interesting to see if the flowers have actually been pollinated and produce seed.

I understand that the flower buds might be predated by the tuart bud weevil. So I have been looking for the small holes drilled in the side of the bud cap, and also the offending weevil but haven’t seen any evidence of them.

???? like your comments

Katinka Ruthrof: Dear Colin,

Its great to hear that flowering is occurring in Bunbury too. A few weeks ago I received an email from an observer near to Lake Clifton who reported mass flowering in that site as well. I find it also interesting to hear about the short flowering period and flower loss. It could be due to a number of factors that can impact the bud between now and fruit development. For example, the buds can be predated upon (weevils, as mentioned), the flowers can be rain or hail damaged (did Bunbury receive a lot of rain during the storm?), pollinators could be lacking, or parrots can clip them off. If they survive all of that, they might become fruit! It’s an amazing process.  So, the number of bud caps seen may be much higher than the number of flowers and hence the number of fruit.

We could do some phenology studies (studies of how plants and animal life changes over the seasons)  to follow a number of buds through their cycle. I share your amazement Colin and it will be interesting to see what happens next. What do you think, would this be an interesting school project?  Low hanging branches with buds are easy to study for children. Is the mass flowering a sign of the last gasp of a species to cope with a impending death, or, and I like this thought better: is it a sign of healthy trees responding to good weather conditions? Or is it much more complex than that? Next summer will tell us more about the significance of the mass flowering… Other observations are welcome!

2010 is shaping to be a fantastic year for eucalypt flowering and fruit crops. The prolific flowering of marri (Corymbia calophylla) and powderbark (Eucalyptus accedens) trees around York and the Helena Catchment is being copied by wandoo (E. wandoo). Many trees are laden down in bud, ready to burst into flower. What happened!?

Recently I visited Pat and Bruce McGregor’s farm near York to photograph this massive budding event, something they have not previously witnessed in such quantities. As we drive around the farm, the wandoo trees portray a picture of health – vigorous green canopies full of bud and fruit in different stages of maturity, clearly visible by the glossy green-brown colour amongst the leaves. Bruce says many larger limbs have broken due to the weight of their load. It is difficult to believe that 8 years ago these same trees were a suffering serious crown decline, and looked extremely sick. Bruce and I have both seen wandoo take the opportunity and flower at various times throughout the year, including December, April, May, July, August and September.

Bruce McGregor shows off the heavy bud crop carried on his wandoo trees (photo by Liz Manning).

Bruce’s powderbark trees reveal an impressive crop of fruit as well as new buds amidst remnants of flowers (photos by Liz Manning).

To find out more about wandoo’s flowering and production cycles I talked with David Leyland, a beekeeper of 27 years who works bees in wandoo around York and Moora. Ryan Hooper has also keenly observed wandoo’s reproductive capacity and phenology. Ryan and Dave shared their observations and knowledge in answer to my questions.

Question: What is the time span from bud to flowering to seed development?
DL: It takes around 2 years from the first sign of bud to flowering. Once trees flower, within 12 months seed could be mature. Wandoo trees can carry up to three years of fruit and can continually put bud on if the seasons are right; rain and warmth can induce the tree to put on another crop. This is especially true in the York area. However, thunderstorms can have the opposite effect). For example, in 2008 when a humongous downpour knocked all the flowers off, the trees stopped flowering and I had to take the bees off. Over the last 10 years wandoo honey yields around Bruce McGregor’s farm near York have been very low. Other eucalypts such as Salmon gum take advantage of good climatic conditions by flowering at different times of the year, and carrying three years of fruit.

RH: Interesting. I agree except that in terms of seasonality it appears that North to South distinction (northern trees flower and perhaps produce buds spring-early summer; southern early summer to late summer) is moderated through years with favourable conditions. Although data has not specifically collected on optimal conditions, other studies on Eucs suggest that optimal conditions are related to moisture x temperature. Obviously moisture is not solely governed by rainfall as different species have different niche constraints and hence, water-use strategies. For Wandoo, an opportunistic growth strategy implies different conditions between years result in variations in times for bud production-maturity (and hence seed production) and different cycles of loss and gain of leaves and reproductive structures. Interested readers can click this link to find an excerpt of a study that I have carried out.

Question: 2010 has seen a mass flowering from a number of eucalypt species (marri and powderbark). Wandoo is also carrying an enormous crop of bud. What does this mean for flowering, nectar and honey production? Does this change with different locations, soils, and climatic conditions?
DL: Temperature and climatic conditions certainly have a strong influence what happens. Normally with marri when it flowers it yields nectar and honey, with every 3rd year being a bumper year. However, the recent hot windy conditions over December – February shortened the marri flowering to only four to five weeks. At Chidlow the marri flowering was only average, while along the York Rd up to Bruce’s farm, the flowering was very good, but this could be much less next year.

Jarrah will sometimes flower but not produce nectar, or it can flower and then abort its fruit, or abort the buds before they flower. About 60% of jarrah’s buds can be aborted before it flowers. Powderbark can yield well but it is very unreliable. However, over the last 10 years it is becoming more reliable. This year the powderbark has given its best flowering for a number of years.

The wandoo trees are looking really healthy and carrying a huge crop of flowers which should mean a good honey yield, but this depends on temperature and rainfall. We will need good winter rains. Wandoo does not seem to abort as much as jarrah, however thunderstorms can knock the flowers off and reduce crop, as happened in the spring of 2008, at Bruce’s farm. In Walebing (20kms south of Moora) the wandoo flower crop looks good but is not as impressive as York. The wandoo around Moora have consistently produced about every 2nd year; sometimes 2, 3, & 4 years in a row.

RH: Don’t know much about nectar production, but I know a range of soil types occurs under Wandoo and therefore, it would be expected canopy density, bud production etc., to vary according to these what we as scientists call “micro-niche factors”

Question: Has the decline of wandoo affected its flowering and honey?
DL: Yes, over the last 10 years the trees haven’t flowered as well or yielded much nectar, particularly around York. The last time I worked wandoo on Bruce’s farm was 2008. At Walebing there have been no obvious signs of wandoo decline as has happened in York, but I have observed decline occurring in the last 2 years and can see it moving up the Great Northern Highway.

RH: Yes, but only with severe decline. Also, recovering trees once beyond a threshold of foliage re-growth (2-4 years growth) are producing buds and flowering as normal.

Question: Despite declining rainfall, wandoo’s health is improving. What have you noticed about the flowering over the past 10 years?
DL: A lot depends on when the rain falls. If rain falls in October then marri will flower well. Wandoo can flower at different times throughout the year. If the weather is warm enough in June and July, the wandoo will flower and only seems to stop when the weather gets too cold and wet. Once weather conditions change, the trees will start flowering again. At times wandoo can flower but not yield nectar. This has apparently happened in areas north of the Great Eastern Highway, around Clackline and Toodyay.

You can see the affect of the drought on Jarrah, but it doesn’t seem to have affected the wandoo and powderbark in their health or their honey production. We seem to have been through a lean period, but this now appears to be changing. Over the last 10 years flowing and honey yield seem to be improving.

RH: I am very interested in Dave’s observations and they appear to differ to mine with respect to a focus on rainfall per se and ambient cycles for flowering but nevertheless life would be boring without different perspectives. I found rainfall to be mediated at the micro-niche scale (that is soil type, stand structure etc.,) which in turn varies according to spatial and temporal traits for resource use. Therefore flowering varies seasonally (within natural windows set by temperature x moisture) and inter-annually. All my observations for a short 8month stint with DEC are in the excerpt that you can find at the website of the ‘Wandoo Recovery Group’. Links between flowering and climate, soils, health etc., go beyond nectar production, in my view, but perhaps are beyond the scope of this particular blog.

As you may be aware, we have a seed collection program for Yalgorup National Park (Bulletin 10). We collect seed for a number of reasons, including: to conserve the genetic resource for the area, to undertake restoration trials and carry out broadscale restoration elsewhere.

Late last year we had another seed collection day (technically it’s fruit collection, rather than seed collection) and over 10 people came to help. We were walking towards our first tuart (keeping one eye out for any ticks) when we noticed a number of tuart opercula on the ground. Opercula (Latin for ‘little lid’) are caps which protect the flower during maturation.

Looking more closely into the canopy, we saw that the tree contained a large number of flower buds. Then the next, and the next… almost all of the tuart trees that we saw contained flower buds. This was exciting! These trees have been stressed since the mid 1990’s and we haven’t seen a mass flowering event in this part of the park since.

Until recently, very little was known about tuart reproduction (e.g. cycle of bud production, flowering times, number of seeds/fruit etc.). What we do know (from studies in other parks and anecdotal evidence) is that tuart has a very irregular and intermittent flowering, which leads to a variable seed production and supply (hence seed collecting is not as easy as one would think). For Yalgorup National Park, this intermittent flowering, on top of the massive decline that is occurring, has resulted in very low levels of fruit and seed.

This has larger scale implications for areas with declining eucalypts. Without canopy stored seed, management interventions such as prescribed burns will not facilitate eucalypt seedling recruitment. Indeed, fire at this time could cause massive changes in community structure and facilitate weed invasion. But that’s another blog topic…

Where to go from here? Well, in many temperate eucalypts, flowering occurs one or more years after bud initiation, followed by one year of fruit development. So, if all goes well, the buds will develop into flowers and the flowers will be pollinated, develop into fruit and set seed. Then hopefully the fruit will survive any pre-dispersal seed predators (e.g. those with beaks). If all that falls into place, book it into your calendars everyone, next summer we will hopefully have plenty of tuart seed to collect.

After 6 weeks of trapping for small mammals, amphibians and reptiles in wandoo woodlands I feel safe to say I have seen some amazing fauna and some funny sights.

From the large varanid who stuffed himself inside an Elliot trap as the rolled up tissue paper smelt like a house mouse from the night before, to the western pygmy possum who was sheltering underneath the larger western spotted frog in a pit fall trap (lucky frogs are insectivores) and the capture of the red tailed phascogale (Phascogale calura), an endangered arboreal carnivore that is not easily trapped.

All of these events have occurred at Dryandra State Forest and Wandoo Conservation Park where I have set up 24 trapping grids to investigate the impact of wandoo crown decline on the wildlife of the area. Using three types of pit fall traps, elliot traps, funnel traps and cage traps I have caught dunnarts (Sminthopsis grisoventer), mardos (Antechinus flavipes), pygmy possums (Cercartetus concinnus), geckos ranging from the large Underwoodisaurus milii (barking gecko) to the small Crenadactylus ocellatus (marbled gecko), skinks including the large king skink (Egernia kingii) to the tiny Morethia obscura (obscure skink) and the common bobtail, varanids, blind snakes, legless lizards, dragons, elapids, over 200 frogs, one echidna (Tachyglossus aculeata) and the list goes on.

So after all of these very early morning and hours of digging in very hard clay soils to install my pitfall traps what have I learnt about wandoo crown decline and its relationship with the fauna? I have discovered that fauna is completely unpredictable and looks at the habitat structure from a completely different perspective to you and I. Very few species trapped so far demonstrate that the decline is impacting on their environment. Lack of a solid relationship between the decline and trapped species could be explained by the patchiness of the wandoo decline enabling species to avoid those trees demonstrating decline and head straight for healthy wandoo trees or vice versa depending on their preference. Throughout the next year further trapping will continue to attempt to reveal the links between wandoo crown decline and wildlife. Commencement of bird surveys looking indirectly at the impact of wandoo crown decline on their food resources, terrestrial vertebrate diggings and other signs of activity will be monitored to investigate how larger vertebrates use trees in different states of health and if there’s time, tracking pygmy possums to investigate their foraging resources.

Pieter Poot: By loosing some of its branches and many of its leaves an adult tree will actually have more water available for its remaining leaves, making it less likely that the whole tree will die. Of the four Eucalypt species that were compared, Wandoo and Powderbark Wandoo were shown to have different mechanisms to cope with drought than Jarrah and Marri. During dry and hot conditions the first two species will keep the little pores in their leaves (i.e. stomates) still somewhat open ensuring some flow of water up to their canopies. In contrast, Jarrah and Marri close their pores under these conditions, causing branches to die. As a consequence the leaves of Wandoo and Powderbark can remain active (i.e. take up carbon dioxide from the air to produce sugars) even during hot weather. However, leaving their stomates open during these conditions does dry out their leaves considerably. The research showed that both Wandoo and Powderbark can actually cope with these very dry leaves. Under high tensions (i.e. when leaves are getting dry) the water columns in the stems of these species are much less likely to break than in Jarrah and Marri. Also, when their leaves are drying the cells in their leaves will collapse (like a balloon that is loosing air) much later then those in Jarrah and Marri. This may explain why Powderbark and Wandoo have a more inland distribution.

So, if Wandoo and Powderbark have such a coping strategy, why is it that we seem to be seeing more dying Wandoos than any of the other Eucalypt species? Partly, this may be related to the particular habitat that the species occur in or have evolved in. Wandoo mainly occurs lower in the landscape than the other species and prefers clayey soils. Although these low lying soils receive a lot of run off water in winter and spring and thus seem to have plenty of water, it is extremely difficult for plant roots to obtain water from a dry heavy clay soil in summer. By being able to tolerate their leaves to dry out to a large extent, Wandoo trees are actually still able to extract some water out of this very dry soil. As these heavy clay soils are extremely difficult to penetrate some researchers suggest that Wandoo has relatively superficial roots compared to the other species and thus may rely to a larger extent on this relatively ‘young’ (i.e. last years) water in the topsoil. In contrast, the other species that often occur higher in the landscape may rely more on deeper roots that access deeper and older water. Thus, Wandoo’s allegedly relatively superficial root system, its dependency on shallow ‘recent’ water and its preference for heavy clay soils may all contribute to its vulnerability to the drought that WA is experiencing over the last 30 years. As most Wandoo trees with crown decline have been shown to be infested with insect borers and pathogenic fungi (see Ryan Hooper’s research) the drought stress may cause them to be more vulnerable to these pathogens. Future studies demonstrating the effects that drought has on a tree’s vulnerability to pathogens will have to elucidate whether these ideas are right!

Was it to be a Roadmap, an Agreement or a Treaty? In the very end, it became ‘but’ an agreement with a commitment to limit global warming to 2°C. What do they mean by commitment? It gives an odd feeling, this agreement, as temperatures outside are swinging around 40°C now and temperatures in Australia are breaking new records almost every year. Unfortunately, the Copenhagen agreement has no teeth. No deadline for a legally binding treaty, no commitments to CO2-reductions and no reduction target for the long run. I am telling myself that it is normal for these processes to take a long time…

So what is next for us? While Copenhagen came to a standstill in December, we went out in the Wandoo forests, to select sites for future research and, later on, to participate in a field trip organized by Liz Manning. We found that in some areas the Wandoo were doing remarkably well, but why were they not doing so well at other spots? What makes the difference? How about the Tuarts in the coastal zone? At seed collection day with volunteers, we found many Tuarts full with buds and yet some other trees were obviously suffering. If it is about global climate change, why then are results so differentiated and local? Though Climate Change for some has become an empty signifier or an umbrella term for a whole range of phenomena, it is also a trigger for relevant research as far as we can judge it; to what extent does a shortage of water affect the trees? Are they able to adapt? What are the conditions in which they can? What is the role of borers and fungi? Etcetera. Regardless of Copenhagen, there is work to do in 2010! We wish you an explorative productive new year with plenty of common sense!