On top of the world on an ecological tour

The second full day of IFFA’s ‘Alpine Adventure’ trip to the Bogong High Plains involved two short walks led by alpine ecologists, Dr Suzanna Venn and Dr John Morgan. We could see firsthand, the projects that were being undertaken by these scientists and learn about the exciting opportunities and challenges they face in conducting their research. ` 

Our first walk was led by Suzanna Venn, winding our way up through stunning herb-rich grasslands, Snow Gum woodland and granite outcrops to the 1824m summit of Mt Cope. Suzanna’s interests have led her to research the processes that shape vegetation patterns in alpine areas. At the beginning of the tour, Susanna challenged the group to observe and think about what factors may be driving patterns in the distribution of vegetation in Alpine regions. It was obvious from first observation that snow, wind and aspect are major factors influencing vegetation in this region. 

The Snow Gums were the only canopy tree found at this altitude, where they could be seen growing in dense patches on the rocky outcrops. The trees were stunted in appearance with their short, thick and gnarled ghostly white trunks. Suzanna pointed out that the Snow Gums are distributed in dense patches to protect each other from the harsh Alpine conditions. This reminded me of images of Emperor Penguins huddling together en masse to survive the Antarctic winter. 

Another interesting thing that Suzanna showed us and spoke about were fire disturbances. We were able to see the recent impact of a lightning strike and a small fire scar. The scorched remains of small shrubs, grasses and herbs indicated that a low intensity fire had been recently sparked where the lightning hit the ground. However, it was evident that the fire rapidly became exhausted by the herb-rich vegetation and lack of dry combustible material. This highlighted the resistance of the Alpine ecosystems to fire and the fact that they probably didn’t burn that often. 

Suzanna discussed how shrubs are increasing in these areas and so too are the risk of frequent intense fires, which are known to be a major threat to many of the plant and animal species in these sensitive ecosystems. She expressed her concern how certain shrub species are acting as ecosystem engineers in Alpine regions as they continue to encroach on grasslands and herbfields, outcompeting or shading out the former species. Her research has demonstrated that the shrubs both influence and benefit from positive feedbacks involving fire and snow drift, creating conditions more favourable for shrub dominated vegetation communities. Suzanna highlighted that this problem is likely to get worse with predicted increases in temperature from climate change. 

Our next walk was with John Morgan, who took us on a fascinating historical walk to see the grassland exclosure plots constructed by the pioneering alpine ecologist, Maisie Carr. Her grazed and ungrazed plots were established in Pretty Valley in the Bogong High Plains in 1946 and are still operating and being monitored today, providing a unique legacy of data going back over 70 years. Each of the plots were monitored for vegetation along 44 transects. John described the importance of Maisie’s research and how revolutionary and ambitious it was at the time, when conservation research was almost unheard of and only the hardiest cattlemen dared venture up into the rugged and remote Alpine regions. 

The purpose of Maisie’s research was to investigate whether cattle grazing was having an impact on vegetation and soil erosion, which could lead to water problems such as siltation with the potential to affect a proposed reservoir. That issue had been raised by the Snowy Hydro-electric scheme, which was to begin development around that time. By 1954, results from Maisie’s study showed that inside the plots where cattle could not enter, there was much less bare ground vulnerable to erosion. Subsequently, cattle grazing was banned in the Kosciuszko National Park and the catchments that supplied water for the Snowy Hydro scheme. 

John explained that unlike NSW and Tasmania, the alpine regions of Victoria had experienced a history of around 170 years of cattle grazing, prior to it being removed in 2005 as part of a controversial conservation objective for the Victorian Government of that time. The impacts of the herbivores are known to have had a profound effect on the composition and condition of vegetation in the region. Interestingly, John said that quite a few rare plant species are easier to find in the Falls Creek Alpine Resort than the surrounding national park because grazing ceased in the resort much earlier. 

John also discussed the dynamics of grazing and fire on alpine vegetation, highlighting the importance of long periods of time before each episode of burning. 

An interesting issue that John Morgan brought up was the misconception that indigenous woody shrubs such as Grevillea australis were taking over the alpine grasslands and herbfield areas when grazing was excluded and therefore needed to be managed through controlled burns. This, he explained would only exacerbate the problem, given that fire and grazing are what caused an overabundance of young and dominant shrubs. John explained that we need to look at alpine vegetation management in the long-term and that over time, Grevillea australis grow outwards and undergo a process of senescence, deteriorating with age from the centre, forming a ‘donut’ like hole in the middle. This hole, he explained plays an important role in providing space and protection for the more sensitive grass and herb species. 

John then took us on a stunningly beautiful walk through some alpine heath and carefully past some sphagnum-dominated vegetation communities. I found it important to see the sphagnum moss wetlands, or ‘peatlands’ as John prefers to call them, up close and to see how ancient and fragile these ecosystems are. Apparently, the sphagnum moss clumps are between two to three thousand years old and it takes forty years for rainwater to recharge the aquifers and filter through to the ponds in the peatlands. It was disturbing to see the dramatic scars in the sphagnum moss peatlands where cattle had created deep tracks across the water bodies. Even though the cattle had been removed for over a decade, it appears the scars were going to remain for a long time, if not indefinitely. The Sphagnum moss is very sensitive to being trampled on by cattle, the pressure of their weight pushes out the water within the clumps, thus causing them to dry out. 

The final part of our guided walk was to view a climate change experiment, constructed by John and his colleagues back in 2003 to monitor the impacts of climate change on alpine vegetation. This experiment forms the Australian component (OZTEX) of a larger project called the “International Tundra Experiment” (ITEX), where globally countries with alpine environments are assessing the effects of higher temperatures on cold-adapted vascular plant species by passively warming the air inside small open-topped chambers (OTC’s) that act as weak greenhouses. Overall, the results have been consistent globally, where woody shrubs have benefitted with the warmer temperature and grasses have shown to be adversely affected. John warned that this would have serious implications on alpine vegetation communities. So, this was a good precursor for his final discussion, which focussed on why we should care about conserving alpine regions and the importance of incorporating risk and uncertainty into our plans for future management of these unique and beautiful environments. 

I WAS fortunate enough to join experienced botanists, David Cameron, Jeff Yugovic and Graeme Lorimer at the end of the day to search for rare plants. We discovered a special location in a valley near Mt Cope that was covered in very rare species, such as the attractive Tasmanian Bladderwort (Utricularia monanthos), a bent-grass (Deyeuxia affinis) known only from this location and Mt Kosciuszko, the heath (Epacris celata), the Alpine Tuft-rush (Oreobolus pumilio), Small Flower-rush (Carpha alpina), Parantennaria (Parantennaria uniceps), Alpine Marsh-marigold (Psychrophila introloba, formerly Caltha) and Snow Wallaby-grass (Rytidosperma nivicola). 

I found their enthusiasm and child-like excitement for discovering these plants contagious. Time seemed to disappear quickly as we carefully made our way around this virtually pristine natural area, engrossed in the diversity of unique and beautiful plants growing there. Overall, I found this experience to be a highlight of the Alpine adventure.