As climate change intensifies, we expect to get a lot more extreme weather events. It’d be great if we could predict how ecosystems will change after those events, but we can’t, for lots of reasons. One obvious reason is – we didn’t collect much information after past events to help guide us in the future.
Way back in ’73, the small town of Raywood, near Bendigo in central Victoria, got 928 mm of rain. On average, Raywood gets just over 400 mm a year, so it was a long wet year. Torrential rains came again in ’74. That Big Wet wasn’t unique to Raywood, and La Nina drenched every town, small and big, across south-east Australia. What impact did that extraordinary event have on native vegetation?
We know the floods of 1973-74 triggered regeneration by river red gums (Eucalyptus camaldulensis) and black box (E. largiflorens) around many rivers and wetlands. But what happened away from the rivers, out on the plains and up in the hills? Did the Big Wet trigger lots of regeneration in other areas as well?
From most regions we have no information at all. Perhaps lots of new plants came up, perhaps none did. We don’t know. That’s a big knowledge gap for such an extreme event. And that knowledge gap is one reason why it’s so hard to predict how ecosystems will change in the future.
Let’s jump forward a generation now, from 1973 to 2010, when La Nina again hit with a vengeance. The spring of 2010 was the wettest on record across Australia. Once again Raywood got a soaking, receiving 904 mm in the year, almost as much as in ’73. A few months later, the summer of 2011 brought even more flooding rains.
What impact did the big wet of 2010-2011 have on native vegetation? Did heavy rains promote lots of regeneration in some areas, but not others? Did some species respond well, but others little? Did lots of new seedlings emerge, only to die later on? Or did nothing much happen at all?
As far as I know, we have no answers to these questions. We don’t have a broad-scale, rapid-response ecosystem monitoring scheme. We probably never will. But this time, it’s not too late to share our observations. Lots of people know what happened in their local area. And we’ve got something big that no one had back in ’73. Social media. Yep, we’ve got blogs on our side.
All of which makes me wonder: this time around, can we leave a better legacy of records than than we did in the 1970s? Can we collate observations from lots of people, across lots of regions, to better understand how extreme weather events affect ecosystems?
Can we crowd source about a cloud burst?
In the next few weeks, this post will (I hope) be read by 400-500 readers across Australia and overseas. If every fifth reader posts a short note in the comments box below, we’d instantly have an amazing collection of observations. And, if many of you pass on this quest through Facebook, Twitter and email, we can crowd source a flood of new stories.
You’ve read dozens of blogs in which I’ve written all the words. Now it’s your turn. Please consider jotting down a short note below, and help us all to learn more than we did in ’73.
What happened where you live, work and play? Did the big wet of 2010-2011 trigger lots of regeneration by trees, shrubs and other plants, or nothing much at all? Which species responded best? If there was lots of regeneration, how have the plants fared since? Are most of them still alive?
To encourage lot of comments, I’ve got two books to give to the two people who send in, or encourage many others to send in, the best responses: Ten Commitments: Reshaping the Lucky Country’s Environment (edited by David Lindenmayer and colleagues) and As If For a Thousand Years: A History of Victoria’s Land Conservation and Environment Conservation Councils, by Danielle Clode.
Bribes Incentives aside, the beauty of social media lies not in a few detailed responses, but in receiving lots of short notes from lots of readers, from the mallee to the alps and the coast. Your observations will be wonderful for everyone to read. No note is too small. If nothing much regenerated, that’s really important to know too. So please leave a comment: What did you get from the Big Wet?
The great comments below have been synthesized in the following posts:
- Wonders of the Big Wet
- The Big Grass years
- The Big Wet regeneration pulse
- Drought, dieback and insect attack
On our property near Numurkah , we lost most of our recently planted tubestock, mainly understory , and have had about 200 red gum sapplings appear along our seasonal creek, all growing very strongly .The tubestock understory plantings are being replaced at the moment .Mental anguish aside , the flood has rejuvenated our property, and those around us, after 12 years of drought .We suffered some damage and were unable to enter our home for 10 days due to floodwater but nearby neighbours lost everything -houses, all possessions, cars, machinery –tough times last year !….Paul Huckett
Hello Paul, thanks for leading the charge with the 1st comment. Many of our human possessions are a lot less resilient to extreme natural events compared to natural ecosystems. I hope your local community gets back on its feet soon. I wonder if red gums will be the big winners from the big wet? It’ll be interesting to see if other readers saw the same thing, or saw other species regenerate well, or perhaps if there are some areas where red gums didn’t establish. I hope your new tube stock plants survive well this time. Thanks again and best wishes Ian
Some random notes – the road from Elphinstone to Bendigo through Sutton Grange passes through magnificent granite country to the east of Mt Alexander. I used to stress about the lack of ‘succession plan’ for the mature river red gums that are a major feature of the grazing land in that area. After 2010-2011 I noticed lots of saplings growing in paddocks, especially those being rested. The big wet must’ve provided favourable conditions for germination and growth in spite of grazing.
I live in box-ironbark country in Taradale, though a closer description of our local forest is box-stringybark. The forest suffered from a massive cut-moth infestation and consequent leaf loss last spring, during the driest 6 months i.e. lowest moisture levels on record, according to the DSE/DEPI, worse than any time during the 12 year drought that ended in 2010. The stringybarks are now looking very sick, many covered with brown leaves or more advanced stages of dying. It’s looking a lot worse than in the 1982 drought. I wonder what future there is for stringybarks in this forest.
In a DSE controlled burn area in the forest to the NW of Taradale, there are areas where the local wattle – rough wattle-is so thick as to be almost impenetrable. Very uncharacteristic of this forest where understorey is typically sparse to non-existent. This growth has occurred post 2011. The area has been burned several times over the past 10-15 years. This is the first time I’ve seen this response.
Thanks for your fantastic observations Christine. I love the granite country around Sutton Grange, so it’s fantastic to hear that the old red gums are starting to regenerate there. It’ll be interesting to hear what others have seen for the stringybarks. Driving down the Hume Hwy to Melbourne there’s a lot of dead foliage on trees in the Strathbogies, and I think many of these might be stringybarks. Hopefully other readers can shed some light on them for us. Thanks again, it’s great to hear such fantastic observations. Best wishes Ian
Here are two observations in concert with your post and the responses so far. Similar to Christine’s post regarding dieback during the recent spring around Taradale, on western slopes abutting Mount Tarrengower in nearby Maldon there has been considerable dieback of mature eucalypts and wattles, including both natural regeneration and planted stock that had thrived under the wet conditions of 2010-11. This notably includes hardy species such as Grey Box, Drooping Sheoak and (?less hardy) Black and Golden Wattles. It appears that successive dryness over spring-summer-autumn 2012-13 has notably impacted native vegetation in grassy woodland and dry forest vegetation types throughout Victoria, from casual observations. Following minor winter respite some plants have ‘hung on’ and are greening up despite the prevalence of dead plants.
With respect to the rains of 2010-11, grasslands in west Melbourne had a productivity surge as many sites required burning over successive years to maintain open swards. On one particular site in Deer Park where forbs are relatively abundant, I casually observed an increase in forb frequency that I suspect related to a combination of high seed availability and an extended period of wet conditions conducive to recruitment (rather than just seasonal regeneration from root-stock). I believe however that the opportunity for recruitment also depended on there being adequate sward gaps, with bare ground prominent across the site resulting from the preceding drought. The most successful regenerating plants were Calocephalus citreus, Eryngium ovinum and Chrysocephalum sp.1, and unlike the woody plants described previously, most of these plants have persisted despite the dry conditions of 2012-13.
Hi Georgie, thanks for a great comment. It’s great to get some observations on grassland herbs as well as trees and shrubs. I’m starting to think that I should have asked for comments on recent dieback rather than recruitment in the wet years. It’s fantastic to hear both types of observations though, as lots of us know what’s happening locally, but not further afield. It must be extraordinarily dry to make drooping sheoak die. Let’s hope we get more rain soon to keep things alive. Thanks again, best wishes Ian
Observations in Gunbower Forest on the Murray:
The cover and richness of understorey flora doubled in response to the high rainfall in 2010-2011 in River Red Gum, Black Box and Grey Box woodland in Gunbower Forest. Further to this, areas that flooded in addition to receiving high rainfall had twice the diversity of characteristic floodplain flora and half the array of dryland flora than areas that weren’t flooded. The drought-driven decline in tree health also eased and rare and threatened flora flourished after the initial flood peak. Wetland flora diversity was however exceptionally low, and dominated by the floating Azolla fern. Luckily many of the aquatic species typical of the floodplain wetlands were scattered through the forest in flood runners and depressions. It was floodplain heaven out there in 2011!!
Hi Kate, thanks heaps for writing in. After the long drought and water allocations to irrigation, the big wet was a godsend for many wetlands along the Murray. I wonder whether the long dry period contributed to the low diversity of wetland flora, even after the floods? Any thoughts? Let’s hope that the wet period arrests the widespread dieback of red gums that occurred during the drought. Did you see lots of new seedling regeneration by the eucalypts as well? Thanks again for writing in, it’s great to hear from so many different regions. Best wishes Ian
I have just finished by honours thesis looking at Eucalyptus viminalis dieback in the Monaro region, which appears to be the result of drought along with an infestation of the eucalyptus weevil (Gonipterus sp.). However there doesn’t seem to have been any recovery in the last few years despite the comparatively wet conditions. I would be very interested to hear about other recent dieback and whether the wet years had any positive effect on trees that were already severely affected.
Hello Katherine, thanks for your comment. I heard of your work via Jason Cummings on Twitter (@ausgreening) when Jason posted this link to an newspaper article – http://www.canberratimes.com.au/travel/blogs/yowie-man/mystery-predator-20130301-2fc4p.html Everyone should read this article as the scale of the Monaro dieback is quite frightening. From the comments that have come in so far, it seems as though two different situations may exist in different areas: (1) in some regions floods seem to have arrested the previous drought-driven declines in tree health (e.g. red gums along the Murray), whereas (2) in other regions dieback has occurred after the drought and floods, during the recent dry spell. Hopefully more readers will send in comments to indicate where both patterns have occurred. Thanks again for your comment, I hope the comments from everyone can help your project. Cheers Ian
We have had a massive dieback event of E. moluccana (Grey Box) in Western Sydney during the last few years. The dieback is due to psyllid attack and has been specific to the one species of eucalypt. This is a dominant tree in threatened Cumberland Plain Woodland and has been the subject of several dieback psyllid attacks since the 1990’s. Opinion seems to be that it is related to the extreme dry/wet climate events in recent years and that the recent event is the worst on record. Markus Reigler of UWS Hawkesbury Institute for the Environment is currently investigating this outbreak and more info can be found at http://www.uws.edu.au/newscentre/news_centre/more_news_stories/climate_changing_for_bug_battle_in_western_sydney
and on other climate change related psyllid and vegetation events at http://www.uws.edu.au/hie/people/researchers/doctor_markus_riegler#publications.
This is the most significant event in our region in the recent wet years I think. Great idea to use the blog to enhance our knowledge with ‘citizen science’! We are currently investigating a way to involve school students statewide in a biomonitoring project. By coordinating schools via the 25 Environmental Ed Centres around the state we hope to produce a large and valuable source of citizen information – we are hoping to link with other existing projects like BushBlitz or BioBlitz or Climate Watch etc. If you have any suggestions for us please let me know! We are still in the planning phase.
Hi Steve, thanks heaps for your comment. Naively, we’d expect (or at least I expected) that a big wet period would promote lots of regeneration in lots of places. However, the comments that have already come in highlight how unpredictable changes can be, with regeneration, dieback, psyllids and weevils in different areas. It’s great to hear that there are many good observations and studies in regions like yours. I think one of the values of ‘citizen science’ like this is that it can document a much wider area of processes than any individual is likely to see. You’ve got much more experience in designing great educational programs than I have, so it’ll be great to see how your program works out and grows in the future. Best wishes Ian
HI Ian and others,
I’m thinking this blog could easily be adapted to a study of “what dramatic changes in landscape vegetation have you witnessed over the past few years?”. Close to home (well in the back paddock actually) there has been little change, even though the paddock is specifically set aside for regen under an agreement with our regional NRM body and the summer rains of 2010 and 2011 would appear to have been the bees knees for seed germination. This may be so, but I suspect the absence of recruitment may be due to excessive grass growth during that time smothering any seedlings that may have germinated. I recall Weeping Grass flowering continuously for about 6 months. Of note is that our paddock has been free of stock since c. 2007-08, and so grass was presumably free to grow at will once rain arrived. Like Paul, we have witnessed numerous deaths amongst the garden shrubs, many of which are 10+ yrs old (shame to lose two specimens of the local form of Banksia marginata). Nearby is a paddock that has fairly prolific regrowth of River Red Gum, Grey Box and Cassinia, and where grazing ceased immediately prior to the rains / end of the drought. I note that in the more marginal / less fertile box-ironbark country around Rushworth / Heathcote, the re-invigoration of the shrub layer has been quite noticeable, although I cant say I’ve noticed any major tree regen (maybe a case of not looking hard enough). This suggests to me that competition faced by seedlings, rather than germination triggers per se, may be most influencial. At the broader scale, as suggested by others, there has been considerable, albeit patchy, dieback – in the Strathbogies most notably amongst stands of Messmate Stringybark (E. obliqua) on shallower soils / sheet rock, supporting Christine H’s observations on soil moisture. On the other hand, as noted by Kate Bennetts (hi Kate!), there has been some fantastic rejuvenation on the floodplains. Billabongs that had been colonised by ‘wheat crops’ of young River Red Gums c. 10 – 20 y.o have been dramatically transformed into truly aquatic ecosystems: the Red Gum deaths have, I figure, been great stimuli for the food chain with the injection of organic matter to the s/m. More broadly, I understand that across western Victoria there has been considerable dieback of Banksia marginata stands, many of truly veteran status. Neville Scarlett has suggested a grub attack ( similar to what was noted by early colonists’), however the phenomena appears to be widespread and apparently associated with dry conditions (I know, horse and cart issue there). As I noted above, the GBCMA has a program of providing incentives to landholders to set aside land for natural regeneration (cheaper than reveg – when it works!) – I will attempt to contact said landowners to see what their impressions are – I have a feeling that those with Callitris stands may have witnessed some good regen over the past couple of years with summer rains.
BTW, Best blog going!
Hi Tim B/Barlow, thanks for lots of great observations. Hopefully they’ll encourage others to compare the trends that you saw against what happened in their area. The variation in outcomes really highlights the complexity of potential interactions doesn’t it. It’s a pity I didn’t ask a broader question in the blog, and the question you’ve suggested – “what dramatic changes in landscape vegetation have you witnessed over the past few years?” – is a great one. I hope it prompts more readers to send in great observations. If anyone who has already posted a comment wants to send in another one to address the broader question, that’s fantastic. Thanks again, best wishes Ian
around my area in general (a 20km radius around 34° 33′ 0″ S, 150° 23′ 0″ E) the regeneration during the wet period was not amazingly different to other years (no doubt I missed much of what did occur) but here are some things that do come to mind (after checking my memories with calendars).
The most noticeable was in wetland communities. Upland swamps responded in a green flush (this is not commenting on diversity) it could have been one species doing well or more than one, I’m not sure.
Other observations were influenced by weed control techniques. At sites that were regularly maintained using a mix of hand removing and spraying many Senecio species (including S. quadridentatus, S. minimus, S. bipinnatisectus and others) all responded favourably – yet these species were also encouraged to colonise over other annuals that were not local.
Lomandra longifolia presented synchronous seed germination over 5 or 6 sites. This seemed to occur post heavy rain around December 2010 (I think). The seed must have been stored in the seed bank.
A heavy rainfall during late 2011 to April 2012 seemed to wipe out a mix of advanced Eucalyptus species (especially in shale soils). This death occurred fairly quick (within months). Some have re-sprouted almost a year latter.
I would imagine that a general picture of wet years would show a flush of grasses and therefore increase the cover (decrease inter-tussock spaces) and reduce the suitability for Eucalyptus seed germination. I have seen Eucalyptus germinate better when there is poor grass cover, however I have also seen many large Eucalyptus on the northern side of Mt. Gibraltar die back and die during 2002 drought. My theory is that Eucalyptus germinate during dry and only seem to become noticeable after more reliable rain.
Moving from grass/ Eucalyptus relationships to shrubs; Bursaria spinosa seems to germinate very well post big wets – just an observation.
One last observation includes a memory of seedlings germinating around ant nests of wallaby grass and wattles (Acacia terminalis).
I almost forgot, the summer of 2010 – 2011 also had a noticeable abundance of Cicadas in the Bundanoon area (not really vegetation, but perhaps linked).
Great idea, I will be interested to see the patterns that emerge.
Let me know if you need more info from the above.
Hi Rus, thanks for lots of fantastic observations. I’m starting to wonder whether I might have bitten off more than I can chew here as so many fantastic and diverse comments are starting to come in. It’ll be fantastic to see how many consistent themes emerge from everyone’s observations. I won’t ask you for any more info now, but I’d encourage you and everyone else to compare the different comments that have come in and see if we can generate some great dialogue among all of the commenters. Thanks heaps. Please everyone encourage a friend to read the comments and write in! Cheers Ian
I have a few observations from the Riverina and Mallee.
I guess we are talking about the period mid 2009- mid 2012? During this period of strange weather there were extremely wet periods and also extremely dry periods in my region. It was the combination of the two that caused some of the unusual things to happen..
2009-2010 The most amazing summer/autumn period I’ve ever seen, with tremendous growth of C4 grasses and other nice summer growing things (Sida, Euphorbia etc). It was also fantastic for regeneration of chenopod shrubs like Rhagodia, which suddenly seemed to be everywhere.
2010-2011 Extremely, continuously wet, causing rank grass to grow, which prevented the regeneration of eucalypt trees in most places (despite climatic conditions being suitable). The exception was where land was ploughed, grazed bare or flooded. In these locations regeneration was prolific.
Unfortunately for some of the river floodplains, the huge flood combined with choking levy banks resulted in prolonged flooding of Black Box woodlands (mostly in the lower Loddon and Avoca Systems). In some places this resulted in the death of the old Blackbox trees, more than 50% in some parts of the forests (Wandella/ Leaghur Forests- west of Kerang). The trees that showed stress during the prolonged flood (ie leaves turning yellow- green), initially seemed to recover when the flood receded, but then promptly died when things got dry again about one year later. I suspect the roots were damaged by the prolonged flooding and they didn’t sufficiently recover before things got challenging again in the other extreme. Levy banks have ruined these floodplains and big floods will continue to degrade these forests as a result.
Other than the levy chocked systems, wetland ecosystems generally thrived on the plains. It was the first time that I’ve seen “flowering” Swamp Lilly (Otellia sp) in the Redgum Wetlands on in my region.. Whilst I’ve seen plenty of this plant in other flood times, the flowering was only ever of the cleistogomous kind, due to the flood period being too short or perhaps nutrient levels too low?. It was really nice to have wetlands with with these Swamp Lilly flowers for a number of weeks. Just when you think you know a wetland you realize you don’t.
I was also quite amazed by the response of flooding within a very ephemeral Blackbox wetland, that hadn’t flooded since the 1950’s. It transformed from a Chenopod woodland into a wetland, with an understory not even remotely similar to what it had before it flooded. The flood killed all the chenopod shrubs and a diverse range of flood stimulated herbs such as Mimulus, Trigonella, Centipeda, Triglochin, Lythrum, etc, came up in abundance. These species only grow following long muddy floods (ie a couple of months), and there is no way the seed was trasported there, so it makes you wonder just how long these seeds can survive. Two of the annual herbs that grew in the drying wetland were new records for Victoria, one of which the nearest previous collection was about 1000km away. When an annual species only grows for 3 months, and flowers for one week, once every 60 years, I guess it could be overlooked… It could also be made extinct really easily.
Within the grasslands Chenopodiacae and other dry loving plants like Ptilotus, hated the continuous wet 2010-2011 period, and showed quite dramatic declines, probably due to the increased competition with grasses, but also increased fungal disease and insect activity.
2011 was the most unusual year in the grasslands, with plenty of subsoil moisture from the previous years drenching, but with almost no winter rain. It’s the first time I’ve witnessed the scenario of no “Autumn break” (ie winter annual germination), but with continued perennial growth. It became a year of only perennials and they did very well living on subsoil moisture.
One big benefit of all the rain was a big crash in Red-legged Earth-mite population. RLEM are extremely damaging to the forbs within the grasslands (I’d say one of the biggest threats to a lot of species) so this was a great outcome. I understand that high summer rainfall is very bad for earth-mite eggs.
Weedwise, the wet years, and abundant grass was great for thinning out the Romulea minutiflora (one of the worst weeds in the grasslands). Romulea seemed to be getting steadilly worse through the dry period prior. I don’t know if something similar happend with Romulea rosea, or all those other nasty bulby weeds in other regions.
In the Mallee woodlands, the rain worked wonders and created abundant growth of understory and lots of shrub regeneration . There was no regeneration of the Mallee eucalypts themselves, except in areas where they have been broadscale cleared . Within their stable woodlands, surviving on their lignotuber, they seem to live “forever” so there is no place for regeneration. The climate, combined with competition, never seem to allow for it, regardless of how wet it gets.
Things have turned around now, most of that rank grass (mainly Austrostipa and Rhytidosperma) have died in the long, hot summer and the grassy understory has reset.. Winter annuals are again thriving in the Riverina and Mallee and there will be lots of wildflowers this spring.
Wow Eris, thanks for a fantastic summary. You must have a great diary, or a far better memory than me – or both! I wonder if we can get encourage some great observations from the NSW Riverina to compare against your observations on the Victorian northern plains? It’d be fantastic to see which patterns occurred in both regions and which were unique to one or the other. Thanks so much for taking so much effort to recount so many precise observations.
To everyone else, it’s been amazing to get so many lengthy observations, and I hope we get many more, but if you just have a short account to tell, don’t be put off by the long comments, as there’s a lot of value in many short observation from different places. Best wishes Ian
Great idea. Have you considered using some of the community accessible sites to get some spatial and photographic data added to this and really bring in some citizen science? Observations like this would be great if backed up with photographs etc showing the changes.
Couple I know of that might work include the Community Web Mapping Portal which could record locations and vegetation condition reports, http://cwmp.spatialvision.com.au/
The new Bowerbird site may be possible, as it allows project/group type images and videos to be loaded and mapped, but is set up for species specific – though they may be able to modify also – http://www.bowerbird.org.au/ and also feeds into the ALA.
Another might be possible with some changes could be the Atlas of Living Australia – http://www.ala.org.au/
Even the new Google Maps give the ability to create these maps etc too.
Hi Tom, thanks for a great suggestion. These sites are fantastic, and I’d encourage everyone to have a look and explore them. Initially I think it’s a good idea to keep things really simple, and to just invite a short comment, as there is potentially more to learn by collating many short comments from many places, than from one or two well documented ones. If this simple starting point encourages some readers to explore and enter data in the online databases, then that’ll be an extra bonus. I hope many readers explore the great links you’ve provided. Thanks again, best wishes Ian
Thought it would be worth pointing these fantastic resources out, even if not useful for this.
Probably should put in some of my own observations of some area of low hills and ranges in the North East of Vic.
The big wet had a significant impact on native grasses which predominantly remain on the upper slopes (too steep to cultivate) of the hills, either in isolation or understorey to open grassy woodlands. As the start of the big wet in this region was summer, with major rainfall starting in February 2010, the perennial warm season grasses were the first to respond -and they responded vigorously. There were areas where the Microlaena seeded for 4-5 months, with Red grass going even longer. Surprisingly, in some areas Kangaroo grass did not seem to go so well until much later, virtually not til the next spring/summer.
Many of the hills and slopes that seemed bare dirt from a distance in late 2009 quickly covered up with these natives where they were still remnant, and improved over 2010 and 2011 with the continued wet summers. Of course the blackberries and particularly St John’s Wort also recovered, with areas suffering major infestations of Wort that had not shown any for years – it does not seem to enjoy drought. The advantage is that many farmers now are really interested in managing to protect these native grasslands after this.
Some of the forested hills recovered well, but there were conspicuous bands on north and west aspects where major die off occurred over the summer of 2012/13 – I think mostly Stringybark and Red Box. There are a range of very obvious bands which showed following the heat, so like others mentioned before this may have been due to the sustained wet, followed by major dry – but I have not been to have a close look at these.
I have also seen many old isolated paddock trees also die off rapidly this summer from the same right across the region.
Thanks again Tom, it’s great to have another account from a different region. If the comments keep on flowing in, then we should be able to see some repeated themes emerging from many regions, plus maybe some unique changes as well. It’s great to hear from so many enthusiastic readers with good eyes and great memories! Thanks once again, best wishes Ian
Hi Ian. Great idea and the comments have been very interesting. I live in the Daylesford area and like Christen from Taradale the most noticable change after the big wet was an explosion of cup moth caterpillars.
We are having another explosion of CMC currently and the canopies of messmates, long leaf box and candlebarks are looking pretty bad. Last spring the regrowth of the canpies was beautiful. But I fear the long dry summer and autumn recently will stress and kill some of those affected.
What grasses herbs and shrubs did boom, have been grazed by an increase in hares. Also I have seen and heard many more foxes than prior to the wet patch.
Hello Paula, thanks very much for your comment. It seems like everyone who has written in has reported another change that hasn’t been mentioned before. The diversity of observations has been fantastic to record. I hope we get more comments to see whether others have seen CMCs and other changes in their region. Fingers crossed that your trees recover well. Thanks again, best wishes Ian
The Big Wet caused massive regeneration of grey box and river red gum around Castlemaine in paddocks, roadsides etc where these already existed. Some herbaceous natives have also done very well, with lemon beauty heads popping up along many roadsides.
On the negative side, exotic pasture grasses have spread significantly and are crowding out the more diminutive native grasses, for instance on my acreage much of the fibrous spear grass (Austrostipa semibarbata) has given way to exotic grasses. This may also be in part (or mostly?) related to a late Spring burn off. Hundreds of briar rose and blackberry have appeared and, especially under gum trees, huge numbers of thistles have become established.
I also note that Dianella tarda is being displaced by the exotic spiny rush- Juncus acutus- in a gully on my road and that the Big Wet has hastened this process.
On roadsides and Government owned blocks containing mainly native vegetation, tens of thousands of bridal creeper seedlings have suddenly appeared. This includes a block that my Landcare group has been working on.
Unless some action is taken, I expect bridal creeper will wipe out vast tracts of roadside and small reserve native vegetation remnants over the next few years.
Interestingly, Bridal Creeper is a fairly rare and innocuous plant in its native South African range according to what I’ve googled.
Hi Mel, thanks for your observations, you’ve noted a lot of changes that haven’t been reported by readers from other areas. The increase in bridal creeper is a big worry. In our area (around Albury), Night-shade (Solanum nigrum) and Red Ink Weed (Phytolacca octandra) both appeared abundantly beneath trees during the wet period. Like Bridal Creeper, I assume that birds spread their seeds continually, but that regeneration occurred in a big pulse during the wet years.
The rate of new comments on this post has dropped off a lot now, so I’ll summarize all of the responses (and award the prizes!) in the next blog. Thanks again, best wishes Ian
On the Southern Tablelands Ecosystem Park Site at the National Arboretum Canberra there was a very good recruitment of Bothriochloa rubra in large dense swards, but on the downside there were huge patches of Dirty Dora (Cyperus difformis) and massive flowerings of St Johns Wort (Hypericum). Both the latter now require serious control measures to get full suite of natives back.
Hello Max, thanks very much for your observations. The C4 grass Bothriochloa really loved the big wet summer and increased in many districts it seems. St John Wort seems to have done the same. Interestingly, yours is the first comment that has mentioned an increase in sedges. In an earlier blog last year on seed banks – https://ianluntecology.com/2012/03/28/theres-a-wetland-in-my-grassland/ – I speculated that these big wet years might be the years in which sedges like Cyperus add lots and lots of seeds to the soil, which then persist for years and years. Perhaps this will be the case in Canberra too. Thanks again for adding to the trove of observations. Best wishes Ian
Loved reading this thanks