An Introduction to Azolla Plants
Azolla, a variety of Duckweed Fern, is a topic of widespread discussion and increasing curiosity among rural property owners, particularly those whose property boasts a waterbody, be it a lake, dam or pond. This divisive and prolific aquatic plant has a tendency to cause ongoing debate about its place in the aquatic ecosystem.
In this article, we’ll cover the fundamental characteristics of Azolla, from its aesthetic deep-green hues that can shift to a reddish tinge under certain conditions to its rampant colonisation of its surroundings.
The question in hand: Do Azolla’s provision of a natural shelter and water purification tendencies outweigh its potentially uncontainable occupation of your dam?
Understanding Azolla
Azolla is a free-floating freshwater fern native to Australia. It exhibits a dynamic aesthetic appeal to many dam owners as its colouration ranges from deep green to reddish brown, depending on its exposure to sunlight intensity.
It thrives predominantly in warmer months and takes a particular liking to water bodies which are still or slow-moving due to its characteristic roots hanging down in the water. Because of its free-floating nature, each adult plant intertwines to form a dense mat on the surface of the water, which can be both advantageous and detrimental to the local ecosystem.
Acknowledging the ideal growing conditions for Azolla development is the first step towards putting effective management plans in place to make sure that the plant’s spread is controlled for both agricultural operations and aesthetic appeal.
Azolla Pinnata vs Azolla Filiculoides: Whats the Difference?
The two species of the genus Azolla that are popularly referred to as the water fern or the mosquito fern are Azolla pinnata and Azolla filiculoides. Despite their obvious similarities, the two species vary in a few significant ways:
- Appearance: Compared to Azolla filiculoides, Azolla pinnata usually has a more deeply lobed look. Azolla pinnata fronds have a distinctive appearance due to their prominent divisions or indentations.
- Habitat: Both species may be found in still or slowly flowing bodies of water, such as lakes, ponds, and dams. They also flourish in comparable environments. However, regional and environmental variables may affect their unique distribution.
- Growth Characteristics: While rapid growth rate is an inescapable characteristic of both species of Azolla, there are some notable differences in how they grow. Neither species grows at a consistently faster rate than the other, it simply depends on the environment in which the genus is populating.
- Nitrogen Fixation: Azolla pinnata and Azolla filiculoides are able to fix atmospheric nitrogen through their symbiotic relationship with cyanobacteria. This mechanism enhances soil fertility and supports the surrounding fauna.
- Geographical Distribution: In different places, Azolla pinnata and Azolla filiculoides may have distinct ranges and distributions. Although both species are often found in Australia, local environmental circumstances and ecological variables may have an impact on their distribution and abundance.
The Benefits of Azolla
While the jury is still out on its status as a potential nuisance, it is important to recognise the plethora of benefits Azolla can bring to the aquatic environment of your lake, dam or pond. Although categorised as an invasive menace by many professional and hobbyist farmers, Azolla can actually play a crucial role in cultivating a thriving ecosystem within your property’s water body if managed correctly.
One of its most notable characteristics is its remarkable capacity for rapid growth. This can be both a blessing and a curse, but whilst we are on the topic of Azolla’s benefits, it is worth noting that its rapid proliferation not only sustains its own population but also serves as a vital source of food for a diverse array of aquatic inhabitants that encourage improved water quality in your dam, as well as having an innate nitrogen-fixing capability.
Fish, insects and water birds all enjoy the veritable feast that Azolla provides, promoting a flourishing habitat for a diverse array of organisms.
Moreover, Azolla’s tendency to form a dense carpet on the surface of the water serves as a protective cover, shielding vulnerable aquatic creatures from predators.
The true redeeming quality of Azolla is its ability to act as a filtration system that siphons nutrients and toxins from the water. While it does have water-purifying abilities for animals and humans alike, it certainly wouldn’t depend on Azolla to be the sole filtration system to clean the water and consider it drinking water fit for human consumption.
Additionally, the remnants of Azolla can be harvested as a potent fertiliser for terrestrial plants. The decaying plant bodies of Azolla enrich soil with essential nutrients, ultimately fostering the growth of lush crops and vegetation. A multi-beneficial plant companion, indeed.
When properly managed, Azolla can truly offer sustenance for both aquatic life and nourishment for the fertile soils of the land.
The Bad Side of Azolla
The virtues of Azolla are undeniable, but do they outweigh the potentially uncontainable colonisation of your farm dam? Left to its own devices, Azolla’s rapid proliferation can quickly transform a healthy waterbody into a full-fledged aquatic nightmare of dense vegetation. These diminutive ferns blanket the water’s surface with an alarming alacrity, inadvertently hindering the vital exchange of oxygen, ultimately suffocating the ecosystem below.
While untamed Azolla can suffocate other submerged plants by absorbing excess oxygen and other vital nutrients, the formation of dense mats on the water’s surface also impedes the much-needed penetration of sunlight beneath the surface of the water for photosynthesis.
This dual assault on the dam’s delicate ecological balance culminates in a barren environment for other competing organisms. In a nutshell, unmanaged Azolla can asphyxiate the water body, ultimately starving other life forms of the necessary nutrients for a thriving aquatic ecosystem, throwing out the delicate equilibrium required for any healthy lake, dam or pond.
Managing Azolla Growth
So, it’s obvious. The presence of Azolla in your farm dams water body is highly beneficial to a certain extent and is contingent on your ability to manage its proliferation rate, which requires a proactive and systematic approach.
As we’ve previously mentioned, Azolla typically sits on the water surface in slow-moving water bodies, which makes its management significantly easier. To effectively manage its growth rate, we recommend a multifaceted approach: Combine mechanical removal techniques, such as manual scraping or the introduction of organic probiotics such as Biostim.
If you are seeking slightly more advanced and less laborious maintenance methods, you might consider oxygenating techniques such as aeration to keep oxygen levels optimal. Additionally, preventative measures such as limiting nutrient influx and establishing buffer strips of native vegetation can help mitigate azolla growth.
By keeping on top of the growth rate, dispersion of plant fragments and the infestation of Azolla in your water body, you can simultaneously maintain the aesthetics and health benefits that this aquatic friend can have on the aquatic ecosystem on your property. While proliferation management can certainly be a labour of love, we believe its benefits far exceed its drawbacks.
FAQs About Azolla
Is it possible to manage Azolla with chemical treatments?
Yes, several herbicides have the ability to significantly lower Azolla populations, but their application must involve both human removal and continuous care. Contact us and we can advise you on the use of these chemicals, i.e. which chemicals, if any, and how to use them.
How can I keep my dam from being taken over by Azolla?
Preventing excessive azolla development can be achieved by limiting nutrient flow, providing buffer strips, and reducing exposure to sunshine. Furthermore, providing off-dam watering troughs for livestock can lower the amount risk of contamination.
Does Azolla have a positive environmental impact?
Absolutely, Azolla may support animal habitat and nutrient cycling in aquatic habitats when managed appropriately. Uncontrolled development, however, can result in problems with water quality and ecological imbalances.