Beyond the War on Invasive Species: A Book Review (Part 1)



I was initially interested in reading this book as our current methods for dealing with weeds on our property wasn’t sitting well with me. I wanted to see how this book would suggest managing problematic weeds.

The book initially reads a lot like Silent Spring, looking at case studies and referencing many scientific sources, which I enjoyed. Although all of the examples were US based, it really highlighted the need to look at the system holistically. The author talks about how there is detailed scientific information on the plant itself, but not the ecosystem in which it ‘invades’. It really brought my head out of just my property and made me start to think about my area as a whole.

My favourite part of the book was at the end, in the section titled “Putting Permaculture to work in Restoration”, in which the author goes through a suggested thinking exercise to help analyse the invasive plant in question and to create a strategy for its management. I thought I would go through it for you, my readers, as I think it would be a very useful tool. Later I plan on doing a post where I use the below technique and apply it to one of the invasive species on my property and create a management plan for it.

Phase 1: Turn on the “Macroscope”

Objective Observation

In this phase it is suggested that you forget everything you know about plants and pretend you are seeing the ecosystem for the first time. Once you let go of all assumptions effective observations can be made. This should include engaging all senses such as smell, sounds and feeling. In Permaculture it is suggested that this period for a property should be at least one year and include all seasons and weather events.

 Phase 2: Site Assessment

This is a research phase where you would accumulate information on your local area. This could include local knowledge, climate data and detailed plant information. Soil and pH testing would also be completed in this phase.

Know Your History

By understanding what is the history of the area a lot can be determined. The book recommends a history of the last 500 years, which in Australia would be mostly native vegetation before human habitation. History of clearing, grazing, cropping, possible pollutants and draining or filling. If possible, it could include the history of how the land was managed by our local Indigenous groups.

Use Science (And Systems Science)

By obtaining data on invasive species and why they are considered ‘invasive’ we can learn a lot about why they are ‘invading’ an area and what purpose they may be trying to achieve. This may include some alternate thinking as the reason why the plants are considered invasive may actually be helping the ecosystem in its recovery.

Seek and Apply Traditional Ecological Knowledge

By understanding what our Indigenous predecessors used the land for, we may be able to determine how the effects of Western influence on the land will result in the invasive species. A very well-known example of this in Australia, is where an endangered tree was protected from fire and was continually dying before it was determined that the fire was required for germination of seeds. So, by exercising the Western way of thinking about the situation the tree became more in danger of extinction. As we now know the Australian Indigenous practiced highly sophisticated land management practices as highlighted in Bruce Pascoe’s book, Dark Emu (affiliate link).

Discover Connectivity among Site Elements and Their Functions

By observing how the invasive species interacts with the rest of the ecosystem we can come to conclusions about what it is trying to achieve. In an area like mine which was clear cut for grazing, you would see that a lot of the native tree cover and other layers is now non-existent and, in their place, there are very few species. Are the invasive species trying to fill a niche within the ecosystem? Probably yes. By asking some questions about the functions of invasive plants we can determine what they are trying to achieve. The following questions could be used.

What is the root structure?
Does it provide nectar or pollen and when? Are there others available at the same time?
Does it provide shade or shelter to animal species?
Does it fix nitrogen or concentrate other nutrients?
Does it accumulate heavy metals?
Does it create a lot of biomass over its lifecycle?
Does it create an edible product for humans or animals?
Is it associated with fungal growth? Which types?
Does it filter water or prevent erosion?
Does it help with soil salinity?
What is its successional status?
Why does it appear? Does it occur in disturbed or low nutrient soils? Shade or sun?
Similar questions can also be applied to invasive animals.
Where does it sit in the food web?
What eats it?
Is it recycling nutrients and where do they come from?
What are the potential yields?
Etc.

I really like these questions as it puts the plant into a bigger sphere and makes you think about what other uses it may have. For example, we know that lantana (a big problem in subtropical climates) creates an ideal nesting habitat for small birds due to their spiky crazy vines. If lantana were to be displaced consideration would have to be put into replacing that aspect.

Get Comfortable with Succession and Disturbances

Succession is an important process in ecosystem restoration. This is clearly seen through pioneer species and their role in setting the scene for more long-term species. Sometimes the native species may require a pioneering ecosystem in order to thrive in the right circumstances.

In the near future I will go through the remaining phases that the book recommends.

Until next time,

Kat

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