Restoring ecosystem stability

There are many aims of ecological restoration. Some might include: to enhance native diversity. To stop soil erosion. To connect fragmented ecosystems. To recover disturbances caused by D9 bulldozers.



In bushfires, firebreaks often get bulldozed along tracks. These areas need to be restored afterwards. Here, in the mountains of Victoria, restoration usually is about getting high vegetation cover back (as soon as possible) to reduce soil loss.
(Photo: Sera Cutler, somewhere near Mt Hotham, 2003)

Given these aims, it is often fairly clear what needs to be reported upon to determine the success of restoration. So, for the above examples, you'd probably want to report on the following:
- changes in native species richness or native:exotic species richness ratio
- reduce bare ground (%)
- movements of habitat specialists between patches via corridors
- increased native species cover and low exotic species cover.

As an ecologist, I'm interested in longer-term outcomes of restoration. I'm really curious to know whether initial recovery predicts longer-term recovery. And, importantly, having restored vegetation, how 'stable' is this vegetation in the decades after it was first introduced.

I think one of the under-reported outcomes of restoration is stability. We know that ecosystems fluctuate from year to year in response to climate and biotic factors - hence, the term "non-equilibrium dynamics" is often applied when considering vegetation dynamics. Yet, as a restoration practitioner, I'm pretty sure that you'd hope your restoration outcomes, while fluctuating across the years, was introducing a vegetation that was rather resilient to big changes. Big change might normally be considered negative change. For example, change could involve (a) invasion by exotic species overwhelming the re-introduced natives or, (b) recruitment failure leading to restoration collapse once the lifespan of the plants has been reached.

Tilman's experimental plots in Minnesota
test ideas about the role of species diversity
on ecosystem function.

Theory suggests that introducing more native species gives the system greater stability. Dave Tilman's experimental grassland plots in Minnesota are often cited as the best example of this - severe drought had less impacts on rich assemblages compared to species-poor plots. Diverse plots also had effects on invasion by exotics (rich plots resisted invasion) and nutrient capture/drawdown (rich plots use more resources, reducing leakage of resources).

However, in the native grasslands that I work in, very few species contribute most of the biomass and occupy most of the basal area, i.e. the dominant tussock grasses. So, is stability driven by many species, or few abundant ones?

This is not something we have much data on in Australia, so I'm not going to be able to answer that question very well at this stage. But, we can use one of the longest running grassland restoration projects in Australia to get insight into the capacity of restored grasslands to persist over two decades and to resist invasion by exotic species.

In the mid 1980s, a group of ambitious (and enthusiastic) volunteers from the Friends of the Organ Pipes National Park teamed up with a state government scientist to re-introduce native grassland plants to an area that had been transformed to exotic species by agriculture.  This was a mighty task, for in those days there was little seed available of the now threatened grassland species, there was little known about the autecology and cultivation of the native species, nor had anyone tried to reintroduce them back into the 'wild' to create the 'wild'!

I dug up some photos from about 1985/86 when I first got interested in native grasslands. Keith McDougall, a fabulous grassland ecologist, took me on as a Student Research Cadet for 6 months, and I helped harvest seed of native grasses, sow the seed in experimental plots testing different establishment treatments,  and then monitored the resulting seedlings and recovery. I've been doing it ever since!

You can see in this photo the plots we initially created.

The experimental plots at Organ Pipes National Park, around 1985. Each 10 x 10m plot is examining
how Kangaroo Grass establishment is effected by treatments such as burning.
About 2-2.5 ha was sown in this way over a 5 year period.
(Photo: Keith McDougall)

Here you can see Kangaroo Grass thatch being spread onto plots that have been unburnt & burnt.
(Photo: Keith McDougall)

Each treatment plot was about 10 x 10 m. The aim here was to create the matrix first - the native tussock grasses - so as to build the grassland structure before introducing diversity later. Exotic species were variously removed by fire, herbicides and their interaction, but only for the initial establishment phase of the grassland. In this ecosystem restoration model, we explicitly assumed that native diversity would increase with time as we first occupied the site with native grasses, then added inter-tussock native species later.

I decided to go back to Organ Pipes recently. I was curious whether the grasses that we had sown (almost exclusively Kangaroo Grass) had (a) persisted after 25 years, (b) had resisted invasion by exotic species. While the plot markers are gone, it is very obvious where we sowed native grasses because the plot outlines are almost still visible. Inside the plots was Kangaroo Grass - at high density, with tussocks of varying sizes hinting at self-replacement,, and seemingly acting as the mono-dominant species we see in nature. And, surprisingly, there were very few exotic grasses present. These were restricted to areas outside our sowings where native grasses had no yet colonised.


Restored native grasses creating a matrix for future re-introduction of native species.
Note the tall exotic grass Avena fatua in the general vicinity of our initial walkways.
Organ Pipes National Park
(Photo: John Morgan)

Kangaroo Grasses dominate in areas first sown in 1985.
Organ Pipes National Park
(Photo: John Morgan)

So, from a field of exotic annual grasses (comprising Avena spp, Bromus spp. and Vulpia spp.) a native-dominated grassland has arisen. This hints at a great (perhaps increasing) stability of the native grassland - one that maintains itself yet buffers against invasion. While native species diversity remains low (reintroducing herbs to the matrix has proven a challenge), one could argue that an unstable annual exotic system has been replaced by a more stable native system. And, importantly, the native system still provides an opportunity to return the ever-diminishing native grassland plants to a secure habitat.

I hope you've found this insight inspiring. And maybe it makes us think about restoration in a slightly different way. We need to create systems for the long-term, ones that can buffer environmental change, and ones that provide us with opportunities to continue to enhance their biological value over the decades.

Botanical literacy amongst Under-Grads

Do you know what these plants are?

 

 

 

 

 

I'd be happy if you knew the Genus or Common Name. If you could get the whole botanical name, I'd suggest you knew your plants.

The reason I ask is because I think many undergraduates that I see in biological science courses don't seem to be very botanically literate. This is an observation rather than a judgement. I have no idea whether this has always been the case, but it seems that more and more students I encounter really have very little understanding of the plant world around them.

Why might this be?

Perhaps plants are harder to 'sell' as organisms, despite their importance for habitat, plant-animal interactions, ecosystem processes, and beauty. Perhaps our urbanizing society explores natural places less, and has less space around homes to 'experiment' with gardens.

To test the idea that under-grads are not particularly botanically literate, I showed a group of students 10 images of plants I'd expect they would know if they had been paying attention to the world around them in Australia. Most of the plants I showed them were common or showy things that you can't help but notice - the sort of magpies, silver gulls, blue wrens of the bird world. Indeed, I'm sure if you showed them these birds, many students would probably be able to identify these species, which kind of would highlight even further that plants are invisible to many people. I showed them all the plants above, as well things like kangaroo paws, pink heath (the state floral emblem) and banksia.

Somewhat surprisingly, they did OK (well, some did - no-one got 10/10). Here's the data - I've plotted the number of specimens correctly identified on the x-axis, and the number of students in each group on the y-axis.

As you can see, 40/79 students got less than 50% of the plant names right. The species that were most recognisable were (sadly) white clover (a weed of natural systems but an important agricultural pasture plant), kangaroo paws (maybe because they are common in nurseries and spectacular to boot), and Golden Wattle (the floral emblem of Australia). Much to my horror, the beaut red-flowering gum above was recognised as a gum tree by less than 50% of students!!!!

The results are perhaps not surprising and help argue for the need to teach undergrads about the biodiversity that resides in their local environment. It's why I teach into a  second year undergraduate course that focuses on the basics of taxonomy, plant identification and plant ecology. These are fundamental skills to be acquired by botanists, and biologists more generally. We think this is crucial - botanical literacy is low it appears, yet many of the applied conservation jobs in Australia rely on good botanical skills. I hear over and over that our grads are valued because they can identify a plant (often the job interview includes a plant ID test), they can sample vegetation (in a quantitative sense), and they can analyse floristic data (using complex multivariate methods).

But, Botany Departments are in 'decline'. In July 2013, the last botany undergraduate in the United Kingdom completed their degree at the University of Bristol (British Ecological Society Bulletin 44, June 2013). Botany has now disappeared from the curricula of British Universities. It's been made extinct! Is this moving with the times, or an admission that plants are just not fascinating enough for students?

We are lucky to have two dedicated Botany Departments in my home state of Victoria - at the University of Melbourne and La Trobe University. Fortuitously, they do very different types of 'botany' - at UoM, there is a strong emphasis on modelling, while at LTU we focus on developing field-based skills, taught in dedicated botany classes with plant systematics and taxonomy an important underpinning philosophy, as is plant identification more generally. We think there is a place for students to have to learn about plant families and their spotting characteristics, to learn botanical terminology and nomenclature, and to collect herbarium specimens for lodging as voucher specimens in university and state herbaria. Others might disagree, but given the low botanical literacy levels amongst under-grads, there is a clear need for such teaching.

I plan to survey the students again at the end of the semester, after a strong prac component that introduces them to taxonomic keys, spotting characters and field sampling (species-area curves, quadrats, cover abundance estimates). The aim (hope) is that they'll improve their scores (making us feel relieved that we've taught them something!), but I'm just as interested in developing their appreciation of plants, and hope that some of them join us again in third year to continue their botanical quest.

[and, in case you're wondering, the plants above are: Themeda triandra, Eucalyptus macrocarpa, Acacia pycnantha, Trifolium repens, Xanthorroea australis]

Advertising research: invasions in alpine ecosystems

Ox-eye Daisy - I think this will
be one of the big threats to
alpine systems in the coming decades.
Photo: John Morgan, Dinner Pain, Jan 2013

Here's a little bit of an advertisement about my research on invasions in the Australian alps. My university is big on doing these little staff profiles (your research in 3 Dot Points!), so I thought I'd share with you.

Go to:
https://www.youtube.com/watch?feature=player_embedded&v=HNWfcrBOUJk

Interestingly, many of my colleagues groan when asked to do this sort of thing, but I see it as very much part of my 'job'. Communicating to land managers, policy makers, peers and the public should be fundamental to the discipline. After all, much of what we do is contest ideas about how nature works, how it can be predicted, and what sort of environmental future we want to encourage. These ideas are often new, challenge accepted paradigms and, importantly, can lead to improved land management. It's unlikely they'll just magically be adopted.

So why are (some) research academics so poor at communicating ideas to those outside academia?

There are some excellent exceptions to this of course! If you follow an ecologist on Twitter, a Blog, or excellent sources such as The Conversation, then you've already come across those scientists willing to engage beyond their own field of peers. But what about how this is perceived?

Personally, I think there is a view that 'advertising' your research can be seen as (a) needy and (b) self-congratulatory. "The work should speak for itself!" Perhaps! But, and as the tenor of discussion at meetings I attend with managers would attest, perhaps this view is (c) selfish and (d) arrogant. Particularly in the current era where scientific publication rates and volumes are sky-rocketing. I have enough trouble keeping up to date with new and exciting research.  To assume that those that use science (i.e. students, managers, governments) need to seek it out themselves would seem to immensely under-value our work. Why would they seek it out........unless they knew it existed in the first place.

This is not a call for ecologists to get on the media bandwagon, nor do stunts to get noticed. Far from it. Rather, I think what I'm really suggesting is that ecologists need to know that the 'users' of their work are really hungry for information. Ecological literacy in the field of conservation and land management is rising and, because there are lots of vehicles to engage with these users, ecologists should be open to engaging in these non-traditional ways.

There is a danger that end-users of information will rely heavily on those ecologists that are accessible to them. Such a narrowing of world views is probably not desirable. But what is really undesirable for ecologists is to ignore the possibility that their research might just have even greater impact if they engage (or is that 'advertise') through new mediums.

What do you wish you'd learnt at University??

Grass-trees in the Warby Range

I've been chatting to former students of late, trying to find out what we could have done at University to better prepare them for life in the workforce/academia. I'm in the enviable position where many of my students have gone on to work in the botanical field and many have gone on to make great contributions - as environmental officers, as university researchers, as advocates for conservation of biodiversity, as government policy makers. Hence, we must be doing something right. Finding out how they could have got more out of their education has been really eye-opening (and perhaps not surprising).

It's clear that former students of mine have two very clear regrets, representing two very different skill sets.

1) Far and away the biggest 'regret' expressed by former students is that they wished they'd tried to learn the major plant families (better than they did!) and, in particular, the spotting characteristics that help you to quickly narrow down your options. Frequently I hear them state that plant identification is a critical skill in their current jobs, but one of the skills not well learnt at uni. Hence, they have struggled with this important aspect of their work. This might be because it is not well taught in undergrad courses or, more likely, as an undergrad it is not immediately clear that such skills are pivotal and hence worth learning well. Teaching the basics is an investment in future ecologists, but one that those future ecologists must be willing to learn, no matter how hard or boring it might seem at the time.

2) A close second relates to statistics. This one is not surprising to me - most undergrads really shy away from mathematics and data analysis more generally. I suspect that a lot of this has to do with the fact that biology students don't immediately see the relevance of statistics. Many just want to get on with improving conservation outcomes, but experimental design, evidence-based management and data interpretation are central to many ecological disciplines and can't be avoided. I always challenge my students to understand their stats, and to be proficient in writing code to generate graphs and simple models. Ultimately, they never complain! Well, that's what I tell myself!

Of the other 'regrets' expressed by my ex-students, the dotpoints below consistently get raised. The idea of highlighting them here is to encourage current undergrads to think outside the box, to engage with concepts perhaps not central to their current thinking about ecology, and to ensure that they are aware of the types of skills necessary in the workforce that (perhaps) only seem like annoying things needed to pass a final exam.

3) Some students really wish they had mastered computer programmes that are now pretty much 'tools of trade' for ecologists - ArcGIS, Access Databases and R get mentioned a lot. I tend to agree. Computers are part of the arsenal of all ecologists, as is modelling and data storage, so it's important to challenge yourself to learn these programmes. Rarely will they be taught in general undergrad courses to levels that approximate 'expert proficiency'. Instead, you often have to master them yourself (with the help of willing allies like Post-Grads and Post-Docs).

4) Contributing to discussion groups. Science is a contest of ideas. But many undergrads avoid serious discussion of concepts, theory and data. I'm not sure why this is (although the obvious reason probably goes something along the lines of "I don't want to look stupid or say something seen as dumb"). This outlook needs to change. Coherently arguing a position, based on well-researched information, is central to decision-making, so any opportunity to practice these skills at uni should be grasped with both hands. One of the things you'll also have to learn, however, is to take criticism constructively.  This ensures rigorous debate, and sound ideas rise to the surface. What might seem like short-term pain will ultimately have a long-term gain to your ability to contribute to the discipline.

5) Time management. We all know the story of the undergrad that leaves their assignment to the last minute or the Post-Grad student that takes two, three, four or more years longer than anticipated to finalise their research thesis. But as your career progresses, you find you have less and less time to do all the tasks that you've been handed. Several students have told me that they wish I'd been harder on them when they failed to deliver what was promised - that if they failed to meet a deadline, there should have been a consequence beyond a stern (but often sympathetic) look. I'm working on this!!! But getting into the habit at uni of meeting deadlines, and developing a system that works for you, can only help you later in the workforce. And being a reliable, efficient team member should not be under-estimated.

6) Ecophysiology. Surprisingly, several students wished they'd taken more classes in this topic. The role of ecology is to understand the abundance and distribution of organisms and, for field biologists, knowing how to measure this is crucial. But what underpins much of this (aside from dispersal processes) is how plants respond to stresses such as water-limitation, frost and extreme heat. These outcomes are often observable as effects on cell or organ function, and it's only after university that some students begin to realise the importance of this.

7) When many students enter university, they do so because they have an interest in a particular species (such as a koala), or a group of organisms (e.g. big cats, whales, orchids). But it soon becomes pretty obvious that it is near impossible to study all species in great depth to understand them, yet the pressures to 'manage' them is high. Many students tell me that they enjoy learning about plants from a functional trait viewpoint, largely because the concept allows conceptualization of responses of whole communities to things such as disturbance, climate change and urbanization. Perhaps we need to teach this concept more rigorously from 1st year level biology, and emphasize to students that the best understanding of annual plants or C4 grasses can be gained by viewing those plants by their traits. Such thinking will need students to move beyond the specific natural history that drew them to biology, and look for broader patterns in nature.

Why grasslands need 'champions'

Because native grasslands exist as small, isolated fragments in an agricultural landscape across most of south-east Australia, they present challenges to management on lots of levels. Indeed, their small size is one of the biggest challenges, mostly because of the perception that small remnants are hard to conserve.



A native grassland on a three-chain wide roadside in western Victoria. A 'chain' is about 22m long, and was used by early surveyors to measure distances for road reserve allocations, blocks, town commons, etc. Ptilotus macrocephalus is the flowering plant you see in the foreground, surrounded by tussocks of the C4 grass Themeda triandra.
(Photo: Fiona Sutton)

Edge effects, weed invasions, small populations, isolation and inbreeding are all very real problems faced by remnant grasslands. But I've found one of the biggest challenges we face to conserve biodiversity in grasslands is to get management implemented. Consistently. This is not meant to attack the people who manage grasslands but, rather, highlight that we need to be aware that despite lots of excellent ecological research that informs management, and the fact that there are many enthusiastic, dedicated professionals and volunteers in this field, grasslands need intensive and on-going inputs to maintain their values. And the difficulty of doing this should not be under-estimated when thinking about management over multi-decadal scales.

I've just achieved one small gain for grassland conservation. In this Blog post, I want to tell you about the journey I had to take because I think there is a salient lesson to be learnt.

Truganina Cemetery is one of the jewels in the crown for grassland conservation in the Melbourne area. It might only be approx. 1.5 ha in size, but it contains large populations of at least two nationally endangered plant species (Button Wrinklewort, Spiny Rice-flower), is species-rich, and hardly has any weed invasion. The earliest gravestones date to the 1860s, and we know there are unmarked graves of early European settlers that date from even earlier times as they made their way to the goldfields of Ballarat. Because it was set aside from grazing at least 160 yrs ago, it retains a complement of native species that are missing from the surrounding grazed, species-poor grasslands. Indeed, many of the native species can only be found in places like Truganina.

Truganina Cemetery in late autumn, 2013. The centre of the cemetery is a superb example of a little grazed native grassland.
(Photo: John Morgan)

Such sites are crucial for conserving local genes of once-widespread species. And they are the place where we might collect seed to develop seed orchards, and produce plants to introduce into conservation reserves when restoration is attempted. We can't under-estimate their role: if we want to save the ecosystem, we have to save all the pieces!

To maintain the plant diversity of native grasslands, the impact of the dominant tussock grasses on smaller, less competitive inter-tussock species need to be moderated. This has been done by burning in many areas, although it is feasible that slashing (and removal of the cut material) could achieve the same aims (as might stock grazing in areas where grazing has been part of the recent history of  the grassland). I've written about this in previous posts, and it's been a central idea in the ecological literature since John Stuwe & Bob Parson's seminal paper on grassland floristics and management effects (see Australian Journal of Ecology 2, 467-476).

At Truganina, the last management burn was approx. 10 yrs ago (in 2002, although the record keeping is hazy on this). Since that time, there has been a long and protracted drought, and this seems to have slowed down the rate of biomass accumulation, such that the necessity to burn has been quite low. It's been interesting to see how grassland productivity at Truganina is tied to annual rainfall (as it is in prairies). In drought years, I'd suggest there has been a decline in grass biomass as litter decay exceeds litter build-up via new tiller growth. But, with the breaking of the drought in 2010-11, productivity increased dramatically. By 2012, it was clear that the grassland needed disturbance (to the vegetation) to open up inter-tussock spaces and if this did not occur, it was probable (i.e. highly likely) that the biodiversity values would be compromised.

No-one disagreed with this assessment. But to get Truganina burnt, our preferred option, took a little longer than might have been hoped and hints that to achieve management outcomes (sometimes) requires persistence and dogged determination.

Bob Parsons and I (and others) wrote to the secretary for the  Minister for Environment in the state of Victoria in December 2012, talking about the need to burn important grassland sites around Melbourne (not Truganina specifically) in autumn 2013 because of the dramatic build-up of grass biomass. We got a letter back from the Regional Director (11th January 2013), thanking us for raising the issue, and that they'd look into this.

On the 29th January 2013, we raised the need for burning at Truganina.

What proceeded to occur was that we had a further 23 emails/phone calls/interactions with the people needed to undertake the burn. These interactions highlighted the need to (a) follow-up on requests, (b) find out the status of proposed actions and (c) nag when things weren't moving in a manner we thought satisfactory.

I want to stress that I'm not having a go at the wonderful individuals that have helped us along the way. Rather, it highlights that managing grasslands in an urban context is difficult! Government agencies, OH&S requirements, contractor availability, the weather and public liability all came into the equation at some stage.

On the 5th June 2013, Truganina was burnt. As the photos show, the fire was low intensity and patchy. Crucially, it occurred before re-sprouting and seedling emergence had occurred, and I'm hoping we will see a flush of growth, flowering and regeneration in the coming year. This is an excellent outcome for this tiny remnant and ensures that the values we cherish so much are likely to hold on for another decade or so.

Truganina grassland - burning for the first time in a decade or so.



Truganina grassland, a few days after burning in June 2013
(Photo: John Morgan)

This experience has taught me a lesson: the value of championing a site. If you have a local grassland that you want preserved and managed well, then agitate for it to happen. I'm pretty sure that with local inputs into local remnants, better outcomes will ultimately be achieved for the protection of those remnants. By championing small sites, we ensure that they don't fall through the management cracks.