Cinderella dams: biodiverse wetlands
In our mid 20’s Ralf and I worked for a revegetation company that specialised in revegetating wetlands both remnant and newly constructed. We established a close friendship with two beautiful passionate young men who wanted to increase and protect habitat biodiversity and did so by starting a small nursery business. They began as a team of two, harvesting seeds, sowing and planting, and grew into a team of many. Over the past ten to 15 years municipal councils all over Australia and State Governments began to realise that storm water volumes were so great that creeks were being further and further degraded and pollutants were contaminating fresh water. Over the short time that new Australians had inhabited this land, swamps and wetlands had been drained to make way for residential or agricultural developments. We had little to no understanding of the ecosystems services that wetlands/swamps provided us. These low-lying areas collected water during great down pours and allowed it to slowly filter through the soil into aquifers, creeks and rivers. They ensured a topping up of ground water, and naturally occurring bacteria and fungi in the soil broke down high nutrient levels and heavy metals. But for soil to act as a filter water must be allowed to pool for long periods of time and trickle through the soil profile before making its way to fresh water outlets. Hence today most if not all new residential developments are required to also establish adjoining wetlands.
With this experience behind us, Ralf and I were destined to create our own wetland on our 15acre property in Blampied, Vitoria. The key to creating a wetland as opposed to a dam, is to ensure that the edges of the wetland have a gently sloping gradient. A dam tries to maximise water volume by having steep sides. If you were to stand on the edge of a dam and you jumped in you would find yourself sinking deep into water. With a wetland the overall volume of water for a similar sized land area is less. If you were to jump in from the edge, your ankles would get wet. This shallow gradient (as well as water clarity and low nutrient loads: Nitrogen, Phosphorus) directly influences the diversity of plants you can establish. Just above the waters edge you can plant native flowers such as Alisma plantago–aquatica with its large heart-shaped leaves and masses of pink to white flowers, as it tolerates boggy soils. While in deeper water up to 1m in depth Baumea articulata, a tall erect tussock can be established. Baumea juncea, which tolerates inundation to 50cm can be planted between the two preceding species.
Each plant with its individual characteristics creates a home/habitat for a range of animal species or invertebrates. The greater the diversity of plants the greater the potential for attracting a broad range of micro and macrofauna to your site.
Below I have posted some images from my day on our wetland. I have planted about 25 -30 plants in the past five weeks. A very small number as the soil is really hard. The planting process includes:
- digging out competing weeds; (including Golden thistle and Gorze)
- digging a hole four times the size of the tube stock (plant size) to ensure drainage;
- mulching thickly with straw; (but not so thick that rainfall won’t get in)
- tree guarding;
- moving gear; (Mattick, hammer, tree guards, bucket, straw to the next planting hole)
- photographing work and a bit of Instagramming along the way for company.
This very pretty flower is called Pseudognaphalium luteoalbum. It has appeared on the far edge of the wetland where the soil is moist but not boggy. I did not plant this gorgeous plant, it has self-sown from seed dormant in the soil? Or has arrived in conjunction with other aquatic plants brought in and planted.
Weeks before planting I had laid out mulch pads using straw left over from our Light-earth build. Where the mulch pads are placed the soil is a little softer.
This is a Sweet Briar (Briar Rose), it has deep strong roots and prickly thorns . It is very difficult to pull out and I have hence been mowing over it to keep it from growing and seeding. Weeds are unwanted plants. This plant is unwanted because it is very coarse and prickly and invasive.
Loved. This is not a weed but a very wanted plant. It is quite soft and pretty and whorly and in the Genus Myriophyllum. The great thing about giving you the Latin name ( which should be Italisised, but I can’t get it to) is that unlike its common name, there is only ONE Latin name for every one plant. The Latin name acts like an ID number and no other plant can have that ID number, while plants often have multiple common names or are known by different common names in different countries and states. The Latin name is an International code so people from all over the world can use that code/ name to research the plant.
Mulch pad exposed. Under the straw mulch the long grass is flattened, soft and moist, the soil too is a little softer and a little moist and hence easier to work with. It is only under the mulch pads that I find large worms. The worms have literally being doing work for me during the time the mulch pads were laid out. Had I mixed some manure with the straw as I had hoped to do, then even more worms would have gathered and worked the soil for me: turning it and ingesting it and creating small tunnels through it. All these worm actions literally open up the soil, let air in and make the soil easier to work. There is noooooo doubt that where my vegetable garden beds are to go that I will establish a layered compost of straw and manure to attract worms to the area I want worked.
A close up of the Sweet Briar.
Well established aquatic plants from past season plantings. The dry looking area is what the plant looks like when it dies back in winter and the lush green its summer resurgence.
A gardeners/ food growers very best friend. I only found worms where the mulch had been laid.
Gorze, Ulex europaeus L. a nasty, horrid unwanted, unloved, unbefriended plant, will never be invited to dinner or a film with me.
Golden thistle, Scolymus hispanicus L. ?
Tools for planting including planting guide book “Plants of Melbourne’s Western Plains”, and my four-year-old daughter’s sandals, which she removes and leaves behind at every opportunity.
Before planting I place tube stock in water to get a good drink. These tubes contain Muehlenbeckia florulenta. I am very excited about this plant. It grows about 2m tall by 2m high. It does not produce leaves but instead has photosynthesising stems. It creates a tangle of intertwining stems so thick that it will screen our wetland from the road and make it possible for me to swim with or without bathers!! Hoorayyy.
Before I can plant I break the end roots so that I can free the seedling from the tube stock. I also squash the sides of the plastic tube to help the plant slip out as well as tap the edge of the tube stock against my palm with my fingers bracing the central stem.
Soil horizon colour. The reddish orange tinge suggests the presence of ferrous or ferric compounds such as Fe3+( Oxidized Iron).
The hole is made much larger than the tube stock and ideally as large as the stake area. Because the soil is so compacted that it is hard to even get a stake in unless it has been loosened.
After the hole has been filled with the plant, two stakes are hammered in.
Tree guard next.
The third or fourth stake is inserted and pulled out so as to make the plastic taut before the stake is hammered.
Water in before tree guards or after or even better once the mulch has been added so as not to disturb and compact the soil with the waters movement.
ooh this picture makes me feel happy.
My arty close-up photo.