Blog on Forest Health » Climate Change

Forests struggling to survive in southwest Western Australia

foresthealth — Wed, 19 Oct 2011 05:16:03 +0000

You may have seen some of the recent publicity about Jarrah deaths which was based on research carried out at by Centre researchers together with staff from the Department of Environment and Conservation. It is a confronting time for everybody who cares about the health of our forests. Our challenge is not to lose heart as we think about the severity and scale of the problem. We must work together to study, adapt and address the causes of these kinds of situations!

Check out this news story which was aired last night on the ABC, featuring our very own Giles Hardy and George Matusick.

Landscape ecology: A useful framework to tackle the complex issues surrounding climate change and the health of our woodlands and forests

foresthealth — Mon, 12 Sep 2011 07:12:25 +0000

By Niels Brouwers

I have recently attended the 8^th World Congress of the International Association for Landscape Ecology (IALE) in Beijing, China. I have been a member of this organisation since the start of my academic career. The concept of landscape ecology appeals to me because of its breadth and integrative nature. It takes a holistic approach in the way we look, live and interact with our “landscape”, and incorporates theories and concepts from both the natural and social sciences. Landscape ecology is unique as a discipline in terms of how it looks at the system under study. It recognises that different elements in the landscape, like forest patches, agricultural land and urban areas, are not contained but interact with each other. It further recognises that landscapes and ecosystems are heterogeneous, consisting of different components unevenly distributed across space, and are continuously changing over time. These characteristics make it a unique discipline within ecology.

It has been argued that in order to work together as scientists, practitioners and the general public, a strategy needs to be developed that can unite our different ways of thinking. To have a framework that people understand and agree upon would be a big step forward in our mission to make our woodlands and forests a place we can enjoy now and in the future.

Within the separate research disciplines there are only few that aim to integrate knowledge and have a sufficient spatial scope that can address large scale issues such as climate change. Landscape ecology is a research discipline that aims to do just that!

Landscape ecological concepts and tools can help us understand the processes that are taking place across the southwest of Western Australia. For instance, technological tools like geographical information systems (GIS) can be used to view and analyse the landscape across scales. The increasing availability of satellite and other airborne imagery has greatly facilitated the advancements in landscape ecology. Now we can use these products and tools to monitor and see our environment change over time. We can see what is happening, when it has happened, and where. This enables us to allocate our resources to the right places and perform more in-depth investigations on the ground to see what climate change is doing and what we potentially can do about it. Using digital maps is further a great way of showing what is going on around us (see picture). We can now potentially investigate and show what is going on in our back garden, our local nature reserve, or the forests across the southwest and beyond.

Climate change does not discriminate so equally will impact on all these separate landscape elements. We will have to accept that the southwest of WA is likely to become drier and hotter over time. Integrating our knowledge on what this will mean for our living environment and beyond is a challenge we have to face. We have to start this process now to be able to make a difference. Landscape ecology might just be the framework we can use to unite our different ways of thinking and come up with sustainable solutions. It would be great to hear your thoughts on this, i.e. if you think that a landscape ecological framework might be a good way of addressing these issues.

Map_GE_Landscape_complexity_Bungendore_Common

A great way to explore the the landscape is using Google Earth (free download http://www.google.com/earth/index.html ). This image shows the area surrounding Armadale/Bedfordale. The green outlines are indicating parks and recreational areas. This clearly shows the complexities of the landscape, particularly between urban and ‘green’ areas, with small recreational areas dotted throughout, and larger natural forested areas intersecting and bordering the urban areas.

Reptiles neglected in times of climate change?

foresthealth — Tue, 12 Apr 2011 08:05:54 +0000

By Mike Craig

Morethia Obscura

In our drying climate, it is interesting to ponder how our native animals will cope with the decreasing rainfall. For mammals and birds, the loss of productivity associated with the reduction in water availability is likely to have negative impacts but any potential effects on reptiles are less clear. Reptiles tend to be more diverse and abundant in low productivity environments, so will they benefit from the reduction in rainfall? Data from a trapping project suggest that reptile activity, at least, is to a large extent driven by rainfall. Data from the summer of 2009/10 showed that captures during the relatively wet months of October and November 2009 were quite high (5.6 and 7.9 captures per 100 trap nights respectively), but that capture rates dropped significantly (to 3.9 captures per 100 trap nights) in December 2009 due to the lack of rain over the previous month. Trapping in March 2010, just a few days after the storms that caused so much hail damage in Perth probably lead to capture rates jumping back up to 6.0 captures per 100 trap nights that month. The pattern in the summer of 2010/11 was quite different. It started similarly with relatively high numbers of captures in October and November 2010 (3.6 and 4.4 captures per 100 trap nights respectively), but then was even higher in December 2010 (4.6 captures per 100 trap nights), probably due to the small amount of rainfall that fell in December that maintained moisture levels to some extent. In contrast, captures rates in March were extremely low (1.9 captures per 100 trap nights), again probably due to the lack of rainfall in the previous two months. So, does this mean that the drying climate will reduce reptile activity so much that they are no longer able to be active enough to find sufficient food? That scenario is unlikely, but it does suggest that reptiles will not be immune from the effects of climate change. How individual reptile species respond will likely vary greatly between species, with those preferring moist, dense sites being disadvantaged and those preferring open, sunny sites being advantaged. Whatever the response, it is interesting to think about how our activities might ultimately affect our most diverse vertebrate group, a group that is too often neglected when we think about climate change effects.

So how can playing with virtual worlds help the real one?

foresthealth — Mon, 24 May 2010 06:09:36 +0000

By Michael Renton

(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.

The real significance of mass tuart flowering?

foresthealth — Fri, 16 Apr 2010 06:07:07 +0000

The following is what Colin Spencer of the City of Bunbury observed. Some active followers of the blogonforesthealth may have noticed his call in the comments section. In response to his observations, and in addition to her earlier blog posting, Katinka Ruthrof responds and … comes up with a suggestion. Food for thought?

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!

A New Year after Copenhagen

foresthealth — Tue, 05 Jan 2010 04:06:34 +0000

By Marleen Buizer, Postdoctoral Researcher

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!