Free Public Symposium on Fire Management in the Australian Alps

WEDNESDAY 21^st MAY 2014, 530 to 700 PM

Hoogenraad Auditorium, La Trobe Institute for Molecular Sciences

LA TROBE UNIVERSITY, Bundoora Campus

Hosted by the Research Centre for Applied Alpine Ecology, La Trobe University

This Symposium will showcase how science answers questions about a current, highly topical management issue in the Australian Alps – the effects of livestock grazing on fire regimes of the Australian High Country.  The guest speakers will address globally important topics such as the evolution of Australia as a flammable continent, how weather and fuels determine fire regimes, fire-grazing interactions, and approaches to assessing the effectiveness of various fire management options, including alpine grazing. This is a public forum about an important land management issue, and there will be ample time for questions and discussion at the conclusion of the talks. The Symposium will be followed by drinks and nibbles.

This Symposium is a must for anyone with an interest in the ecology and management of the Australian Alps.

 

Enquiries and reservations: femaa2014@gmail.com    

Places are limited. RSVP: 15^th May 2014

Full details about venue location, parking & access to LTU will be forwarded after registration.

 

Beyond the 'extinction debt'

The best examples of temperate grasslands of SE Australia, like tallgrass prairies in the USA, now largely exist in small, isolated pockets, and are of variable quality due to a century of more of land use. They're the last bastions of these once great ecosystems.

Basic conservation biology theory tells us that long-term conservation of the ecosystem will be challenging - populations are small and isolated, habitats have been degraded by weed invasion to varying degrees, and interactions (such as plant : pollinator mutualisms) may have already been disrupted.

High quality native grassland on three-chain wide roadside at
Derrinallum. Mt Elephant looms large in the background.
(Photo: John Morgan)

Hence, conservation of the biota will be a challenge.

To illustrate the scale of the problem, thanks to generous funding from the The Myer Foundation, our research team has just recently completed a floristic survey of Melbourne's Urban Grasslands. Our fabulous botanist Ben Zeeman (and team) recently surveyed the floristic composition, structure and population size of selected plant species. In total, we surveyed 79 public grasslands for composition (totalling 1393 ha), did 904 transects defining structure, and made 45,200 species observations. Wow! What an effort. Of the 250 native species we observed, 80% were confined to 20% or fewer sites. Hence, while there is still lots of native plant biodiversity in urban Melbourne, much of it is perhaps on the brink of extinction.

Extinction debt is a concept in ecology that may have great relevance to Melbourne's grasslands.

Extinction debt occurs because of time delays between impacts on a species, such as destruction of habitat, and the species' ultimate disappearance. For instance, long-lived trees may survive for many years even after reproduction of new trees has become impossible, and thus they may be committed to extinction. Extinction debt is most likely to be found in long-lived species and species with very specific habitat requirements (specialists).

Extinction debt has important implications for conservation, as it implies that species may go extinct due to past habitat destruction, even if continued impacts cease, and that current reserves may not be sufficient to maintain the species that occupy them.

So what can be done to reverse the extinction debt in Melbourne grasslands? This is a conversation we need to have. Biologists are telling us there will be a continuing crisis (and they have been very good at documenting declines) but is there a way to slow / reverse the extinction debt?

There are probably several answers here. Using a basic understanding of the threats to remnant vegetation that apply anywhere where land use has transformed the native landscape, I can think of four key things we should be doing.

1) Supplement / enhance small populations: we know one of the main reasons that populations go extinct is that they become small and hence, vulnerable to loss of genetic diversity, environmental stochasicity, and regeneration failure due to the fact so few propagules being produced. Hence, having identified which species are in this category in Melbourne's grasslands, perhaps we should look at bulking up population numbers. This might be done with transplanting plants and sowing seeds. Importantly, such activities should not be restricted to just rare species. Our data tells us lots of species might be in trouble.

2) Promote population turnover: one of the reasons populations become small is because recruitment ceases to replace mature plants. If deaths > births, then it is inevitable that populations decline to local extinction. Hence, rather than just maintaining adults (the thing that we see in grasslands), it is imperative that the mechanisms that allow seedling recruitment are well-understood and, more importantly, the conditions for regeneration are maximised. A focus on seedling recruitment needs to occur. My own work suggests that seedlings of many species require lots of light to survive, and that recruitment is episodic and probably related to years of above-average rainfall. Maybe we can enhance recruitment success by removing canopy (by fire or slashing) and watering plots to see if seedling recruitment improves.

3) Maintain important ecosystem processes: one of the critical processes in grasslands is the effect that dominant grasses have on smaller intertussock species. Strong, asymetrical competition means that Kangaroo Grass tends to win the battle when left undisturbed. Hence, frequent implementation of fire (or some other mechanism such as slashing) needs to occur if you want to maintain intertussock species of the majority of the flora. This is well known, but needs to be implemented.

4) Empower people to care: if we are to avoid a massive loss of Melbourne's grassland biodiversity, we have to make people care about this. Many people already do. There are dozens of terrific Friends Groups, individuals and agency staff who are working tirelessly to improve grassland condition and recognition. This energy needs to be harnessed, and a broader audience cultivated. Those people who live near grasslands have to care about them, otherwise conservation of local diversity will always be a challenge.

Recently I saw some excellent signs that advertise the values of grasslands and their habitats. This was on one of the best rural roadsides for native grasslands there is, so the values are already well-known. But I applaud the local Shire for emphasizing the values of remnant grasslands, and why we should care. This needs to happen in Melbourne, least we lose lots of our grassland flora and no-one notices.

The fabulous signs on the Cressy-Shelford Rd promoting the values of the native grassland
as habitat for endangered species. The signs measures approx. 7 m x 2.5 m and are produced in high quality materials.
(Photo: John Morgan)

Publications from the Lab - 2013

Here's a list of papers that were published in 2013 from my Lab. If you want a copy of any of these papers, feel free to email me at J.Morgan@latrobe.edu.au and I can supply a PDF.

1. Farmilo, B.J., Nimmo, D.G. and J.W. Morgan (2013) Pine plantations modify local conditions in forest fragments in southeastern Australia: insights from a fragmentation experiment. Forest Ecology and Management 305: 264-272.

2. Seabloom, E., Borer, E.T., Buckley, Y., Cleland, W.E., Davies, K., Firn, J., Harpole, W.S., Hautier, Y., Lind, E, MacDougall, A, Orrock, J.L., Prober, S.M., Adler, P., Alberti, J., Anderson, T.M., Bakker, J.D., Biederman, L.A., Blumenthal, D., Brown, C.S., Brudvig, L.A., Caldeira, M., Chu, C., Crawley, M.J., Daleo, P., Damschen, E.I., D’Antionio, C.M., DeCrappeo, N.M., Dickman, C.R., Du, G., Fay, P.A., Frater, P., Gruner, D.S., Hagenah, N., Hector, A., Helm, A., Hillebrand, H., Hofmockel, K.S., Humphries, H.C., Iribarne, O., Jin, V.L., Kay, A., Kirkman, K.P., Klein, J.A., Knops, J.M.H., La Pierre, K.J., Ladwig, L.M., Lambrinos, J.G., Leakey, A.D.B., Li, Q., Li, W., McCulley, R., Melbourne, B., Mitchell, C.E., Moore, J.L., Morgan, J., Mortensen, B., O’Halloran, L.R., Partel, M., Pascul, J., Pyke, D.A., Risch, A.C., Sankaran, R.S-G.M., Schuetz, M., Simonsen, A., Smith, M., Stevens, C., Sullinav, L., Wardle, G.M., Wolkovich, E.M., Wragg, P.M., Wright, J. and Yang, L. (2013) Predicting invasion in grassland ecosystems: is exotic dominance the real embarrashment of richness. Global Change Biology doi: 10.1111/gcb.12370.

3. Mayfield, M,. Chalmandrier, L., Wells, J., Dwyer, J., Bonser, S., Catterall, C., DeClerck, F., Ding, Y., Fraterrigo, J., Metcalfe, D., Vesk, P. and J.W. Morgan.2013. Differences in forest plant functional trait distributions across land-use and productivity gradients. American Journal of Botany 100: 1356-1368.

4. Morgan, J.W., Kviecinskas, P.A. and M. Maron 2013. Effect of proximity of buloke (Allocasuarina luehmannii) trees on buloke early sapling survival in a semiarid environment. Australian Journal of Botany 61: 302-308.

5. Morgan, J.W., Meyer, M. and Young, A.G. 2013. Habitat fragmentation leads to interrelated genetic and ecological processes that likely imperil persistence of small populations of a once-common Australian grassland daisy. International Journal of Plant Sciences 174: 1209-1218.

6. O’Halloran, L.R., Borer, E.T., Seabloom, E.W., MacDougall, A.S., Cleland, E.E., McCulley, R.L., Hobbie, S., Harpole, W.S., DeCrappeo, N.M., Chu, C., Bakker, J.D., Davies, K.F., Du, G., Firn, J., Hagenh, N., Hofmockel, K.S., Knops, J.M.H., Li, W., Melbourne, B.A., Morgan, J.W., Orrock, J.L., Prober, S.M. and Stevens, C.J.2013. Regional contingencies in the relationship between aboveground biomass and litter in the world’s grasslands. PLOS ONE  8(2): e54988. doi:10.1371/journal.pone.0054988.

7. Camac, J.S., Williams, R.J., Wahren, C-H., Morris, W.K. and Morgan, J.W. 2013. Post-fire regeneration in alpine heathland. Does fire severity matter? Austral Ecology 38: 199-207.

8. Venn, S.E., Morgan, J.W. and J.M. Lord 2013. Foliar freezing resistance of Australian alpine plants over the growing season. Austral Ecology 38: 152-161. 

9. McCartney, V.A., Silvester, E., Morgan, J.W. and P.J. Suter. 2013. Physical and chemical drivers of vegetation in groundwater source pools on the Bogong High Plains, Victoria. Australian Journal of Botany 61: 566–573.

 

 

 

 

The earliest evidence for widespread declines in native grasslands in Australia??

Something a little different this week.

Native grasslands in southern Australia have undergone a massive transformation since European settlement. But the evidence for the speed of that transformation has been hard to come by. It's hard to guess whether people noticed the changes, or simply realised one day that grasslands were gone.

The following is an extract of an article from The Australasian, dated 18th October 1878. It shows that within 50-80 years of  settlement, an understanding of the impacts of agriculture on native grasses was already obvious. And, interestingly, there were already calls to develop a native grassland "seed industry". It's worth noting this type of information - perhaps the earliest record of grassland transformation in Australia - because we are still grappling with the same issues in 2014 in many respects.

It should make us reflect on what we now know, and yet how little has changed in some respects. We're still thinking about grazing regimes that promote native grasses & still grappling with how to best produce large quantities of seed. Enjoy.


SUMMER MANAGEMENT OF NATIVE PASTURES

"The deterioration of our native pastures as regards their fattening powers .... is due not only to the removal from the soil of certain proportions of the elements of fertility in the form of bone, flesh, and wool, but in some degree also to the loss of the best and most nutritious grasses, which inevitably occurs under the system of depasturing commonly practised in the whole of these colonies. Whether the grasses are only annuals or are those known as perennials, they must soon die out unless measures are taken to ensure a re-seeding of the ground at certain intervals.

Even the longest lived grasses must be renewed from seed occasionally; the old stools become enfeebled by continuous grazing, and the sorts that are most relished by sheep are actually eaten down into the soil, so that in the course of a few years they disappear altogether from the ground. Of this the common kangaroo grass is a familiar example; it will not bear the constant nibbling of stock, especially of sheep, and as it is often the only green feed, in hot dry weather, the plants are eaten completely out.  Within unstocked or lightly stocked enclosures, as between railway fences, native grasses of all kinds continue to thrive as formerly. They have the opportunity of renewing themselves from seed annually, and as they are rarely fed down they grow far more vigorously than grasses of the same species depastured in the ordinary way.

Here is a lesson of which graziers great and small may take note, if they have any desire to preserve the native grasses from extinction. The question whether it is desirable to preserve them at such cost and trouble as may be needed to effect that object is one upon which old and experienced graziers agree. They all affirm that no exotic grasses fatten so quickly as the native pasturage used to do, and there is an equally general agreement of opinion that the stock are far less healthy on " English grasses " than on the native pasturage of the country.

 

It is a principle in English husbandry, when laying down lands in permanent pasture, to employ as large a number as possible of species. In this they only imitate nature, for on examining a square yard of well-grassed ground it is found that the number of species thereon usually varies from 50 to over 200. In this country the number of species is not so great upon the plains, but there is a very considerable variety of pasture plants in districts having a name for fattening. In attempting to imitate nature, and replace the lost natural pasturage by sowing down, as in England, general mixtures of grasses, colonists have met with little success.

 

In the course of a few years the greater number of the grasses are found to have disappeared, leaving only the most robust, or those which by growing all the year round eventually extinguish the more delicate, which, are, usually, also the most desirable. Whilst, therefore, pastures of English grasses can be easily formed, they are found wanting in variety of food—an element of the greatest importance in maintaining the health of the stock. They supply a great abundance of rank and watery food, instead of the more moderate quantity of sweet and healthful food afforded by the native pasturage.

Seeing, then, the importance of maintaining the health, of our stock, the preservation of the native grasses becomes a matter of the first moment, especially to residents in the warmer districts, in which the so-called English grasses will not thrive. It has been remarked that when once the native grasses are gone a full sward can never again be established. Graziers, therefore, should conserve the pastures, and in order to succeed in doing this they will find it necessary to give some little attention to the habits of the several species as regards longevity and time of seeding. The winter grasses, for example, seed in spring; the summer ones later in the season, and at different periods of the summer and autumn. Unless these points are known and regarded, some important grasses will very soon become extinct, even in pastures which are allowed a season of rest from stock, with the object of permitting them to shed a crop of seed. It is obvious that unless the latter plan be adopted the alternative one of sowing native grass seeds must be pursued, and hitherto this has been out of the question, no such article having been upon the market.

The business of growing Australian grass seeds might surely afford profitable work for many farmers in different districts. Harvesting would, for the most part, take place before the grain harvest commenced; the late grasses would not be ready until after that work had been concluded. We can hardly imagine any line in which more could be made with certainty than in growing crops of native grasses specially for seed. Men of intelligence and good powers of observation would readily determine what species ripen simultaneously, and might, therefore, be grown together. The first matter is to collect sufficient seed by hand, and the present time is the season for commencing."

You can see the original article at http://trove.nla.gov.au/ndp/del/article/2982085

Learning a little about ecological restoration from Pygmy Possums

The restoration industry in Australia of the last 30 yrs has been dominated by the 'local is best' philosophy when it comes to thinking about what to replant at a revegetation site. Here, the use of local-collected seed has been promoted because of the belief that local provenance equates to offspring that are likely to be better-adapted to the site and hence, will outperform non-local ecotypes. It also has the added benefit of conserving local genes that might otherwise be lost as species diminish in the local landscape. This may be true, although there is conflicting scientific evidence on this topic. Locally collected seed for example, if derived from small populations, might have low genetic diversity and fitness may be compromised because of inbreeding depression.

But even if inbreeding depression is not a problem, is this philosophy going to deliver us the restored ecosystems of the future?

The prospect of rapid climate change should, I believe, make us consider shifting the local provenance paradigm in restoration ecology, particularly in highly fragmented landscapes where there is probably zero chance of natural gene flow and species migrations. While plants grown from locally collected seed are often better adapted to local abiotic conditions, uncertainty lingers over their suitability for restoration under climate change. It may be better to source seeds from climates that more closely match the predicted future climate of the restoration project, e.g. to source seeds from drier, warmer climates if the local climate is predicted to dry and warm. To do this will entail a massive shift in thinking, one that is likely to take some time.

One of the biggest perceived problems about introducing non-local propagules to restoration sites is the idea that it will lead to outbreeding depression. In short, outbreeding depression is when offspring from crosses between individuals from different populations (i.e. the 'local' and 'new' populations) have lower fitness than progeny from crosses between individuals from the same population. Hence, there has been a reluctance to mix genotypes because of unknown effects of such mixed matings.  Some people also think that the mixing of genotypes in this way reduces the distinct characteristics of the populations involved, and should therefore be avoided. Outbreeding depression won't be a problem if you are bringing seeds of species to new areas where the species currently doesn't exist. It only applies if you bring new genotypes (perhaps dry adapted ones) in contact with local genotypes.

But this may not always be a problem.

Dr Dean Heinze and a Mountain Pygmy Possum
at Mt Buller
http://theconversation.com/genetics-to-the-rescue-hybrid-mountain-pygmy-possums-born-on-mt-buller-6134

An outstanding example of introducing new / novel genes into a gene pool has undoubtedly been responsible for saving the Mountain Pygmy Possum at Mt Buller. Ian Mansergh and co-workers recently reported on this incredible story of population recovery that is strongly underpinned by conservation genetics.

The Mountain Pygmy Possum (Burramys parvus) population at Mt Buller was about 300 in 1996 but dropped to 30 by 2009. It was on the path to local extinction.  The population had extremely low genetic diversity, offspring fitness was low (babies were small and had high rates of mortality) and there were few males in the population.

The solution was simple. Introduce new animals (with a different suite of genes from the local population) to improve the genetic basis of the species at Mt Buller, even if that meant "mixing" two genotypes that have been separated in space for thousands of years. The introduction of new genetic material to Mt Buller from a population more than 100 km away (the world's biggest Pygmy Possum population at Mt Hotham) has rescued this population from almost certain extinction. Half of the Mt Buller population now contains genes from the Mt Hotham population; the genetic variation has doubled. In addition, because of this genetic shift, the population size has more than tripled since 2009 and male survival has dramatically increased.

So why do we fear outbreeding depression so much?

We have long recognised that populations differ genetically, and often those differences provide adaptations to local conditions. The best scenario is usually seen as preserving genetic diversity between populations. But the evidence is that outbreeding depression is rare. In conservation genetics, it is understood that outbreeding depression can be temporary. When co-adapted gene complexes are disrupted, fitness declines are inevitable but short-lived. Natural selection soon acts on the new genetic opportunities and populations bounce back. With new genetic material, the population may be able to face the new challenges of climate uncertainty.

The recovery of the Mountain Pygmy Possum population at Mt. Buller is a good news story and one that should be celebrated. And it possibly has implications for thinking about restoration of systems elsewhere. Given the dramatic loss of native vegetation in southern Australia, the creation of small and isolated remnants, and the rapid warming and drying of much of the landscape, restoration that thinks about "future proofing" our native species and ecosystems might consider more than the local proximity as the sole rationale for seed collection. One might be drawn to ask: is local species extinction preferable than the introduction of novel genes that enable regional species survival?

Further Reading
Mansergh, Heinze, Weeks and Perrin  (2013)  Gene-pool mixing: Lessons from the high country.  Wildlife Australia 50, No. 4, Dec 2013: 32-35.