Our landscape is always changing - season, weather, management, time, climate and a number of factors can all have an impact. While these changes occur, the plants growing in a landscape will also change as a result. This is what plant succession is all about.
Succession is a regular topic discussed when talking about ecology. Ecological succession is the process by which the mix of species and habitat in an area changes over time. Gradually, communities replace one another until a climax species is reached.
Ecological Succession falls into two key types; primary and secondary succession.
Primary Succession
Primary succession occurs when a landscape first forms or when a new patch of land is first exposed.
Secondary Succession
Secondary succession occurs because of a disturbance that has changed the ecosystem and triggers the cycle to start over. An event like a fire, or volcanic eruption, would trigger this.
In both instances, the succession is over a much larger period of time, all leading towards creating a climax species, most often a forest.
What we prefer to discuss when looking at a landscape is a plant succession which focuses on types and species of plants growing in a landscape now and also on a much shorter timeframe than an ecological succession.
What is a Plant Succession?
Plant succession is the process of a change in the composition of plant species in a landscape over time. This change occurs because of a response to management practices and could take place over decades, years, or even just a season.
From the viewpoint of a farmer, a landscapes plant succession can go forward (more palatable and productive plants) or it can go backwards (less palatable and productive).
A landscape’s current position in the plant succession order is a snapshot of how that landscape is performing at that point in time.
By observing and looking at the growing plants, you can determine the placement of a landscape in the succession. They provide a snapshot of where your situated.
The plant succession we talk about in Natural Sequence Farming contains three primary groups;
- Accumulators
- Exploiters
- Balancers
No matter what landscape you’re in, you will find these three groups and they will contain all the plant species you are used to seeing in your pastures.
Accumulators
Accumulators are the first part of a succession. Their role is to accumulate fertility and build the landscape to a point where more fertile plants can grow.
Accumulators move through their succession from early through to late. The harder and less palatable a plant, the further down the succession it moves.
An example of accumulator succession could look like.
Characteristics of an Accumulator
- Woody plants
- Thrive in harsh conditions
- Low to no fertility
- Low to no palatability for livestock, although exceptions in the latter part of the succession
- Prickles
- Tannins
- Deep rooted
- Most root activity below the level of grass roots
- Rapid growth
Exploiters
Exploiters are plants that grow because of the fertility produced by an earlier plant. They exploit the fertility already present in a landscape and, as a result, will not grow without the suitable hydrology and fertility.
Exploiters move through from low fertility to high fertility. Despite relying on fertility being fed to them, exploiters will still be found across a wide variety of conditions because of their adaptability.
Some species are also capable of moving through different stages of fertility. As fertility declines, so will there palatability, and as fertility increases, so will palatability.
An example of exploiter succession could look like.
Characteristics of an Exploiter
- Smaller leaf size, but larger amount
- Fibrous roots
- Low to high fertility
- Low to high palatability
- Light, small seeds
Balancers
Balancers are at the end of the succession and grow when fertility has become too high. Most commonly it is when nitrates have become too excessive and a species comes in to balance the carbon:nitrogen ratio of the soil.
These plants have an excellent ability to capture carbon and feed microbes to balance the soil.
An example of balancer succession could look like.
Characteristics of a Balancer
- Quick growth
- Excellent ability to capture sunlight through big leaves
- Large amount of biomass
- Often dark green leaves
- High fertility
- Low palatability
- Can be toxic
- Tap-rooted
Why Should I Look at my Plant Succession?
A plant succession provides you with a view of how your landscape is performing and where it is on the scale of succession. Over time, it can also provide you with a sense of where your landscape is going, whether it is moving forward or going backwards, just by observing the types of plants you see growing in your landscape.
By looking at the symptoms the plants are showing, it can also provide the answers for how a landscape could be repaired. The symptoms showed by a plant can lead you on a journey to implementing a management change that fastens the succession to a higher order plant.
What Should I Be Aiming For?
A diverse mix of plants is always better. Our goal is for a pasture to contain as much diversity as possible that includes a mix of grasses, legumes, herbs, forbs, shrubs, vines, trees and, yes, weeds. Anything that is green and growing is providing a service and managing your landscape.
In Back from The Brink, Peter, discusses a trip he took to the United Kingdom where he met a thoroughbred breeder in England and found a long held belief “that a good pasture should contain eighty different plant species. If a pasture had forty or fewer species, it was considered to be in decline.” It was known then that diversity was key.
The way we manage our landscape will determine the percentage makeup of that mix and the types of plants growing in it.
Every part of your property will be different. Even within the one paddock you might find a spot where this one particular plant is growing dense, but ten metres away it’s completely different. That’s because every part is at a different point. The soil is different, the soil life is different - and therefore the plants are different. You can never get it to be all the same and you don’t want it all the same, as simplicity will always result in decline.
You want to use your plant succession as a tool to guide you on a journey of making management changes to get the succession moving in the direction you want. A direction that sees you increasing production and improving your landscape. And remember, a healthy succession will always be one where diversity is high.
