Ecological succession fascinates me, especially how it relates to our yards and homes. The term refers to the way ecological communities (i.e. ecosystems or land areas) develop over a period of time after a major disruption. Each stage of succession provides more plants and animals places to thrive while interconnecting different habitats. For me, the most important thing is that succession has stages and that these stages start after something has gone really, really wrong.
As I mentioned, ecological succession starts after a disruption. One example of a disruption is a forest fire. The fire burns down all trees, shrubs, grasses and other plants on the land. It also either kills any animals in the area or chases them away. What’s left is a scorched landscape blacked with ash.
Disturbance in the Force
Another type of disruption is when a much more devastating occurrence happens such as a volcanic eruption. In this case, lava flows over the landscape coating it with a thick layer of magma. It essentially does the same thing as the forest fire by killing everything in its path and/or chasing all the living things away. The difference is how each disruption interacts with the soil.
If you are a gardener or an avid landscaper, you know that soil is the root of all good things in your yard. If you have rich soil, your plants will be happy and healthy. If you have degraded soils, you get weak and unhappy plants. With a forest fire, everything burns but the soil is still connected to the surrounding environment.
With the lava, you have a completely different situation. When the magma cools, the soil is completely cut off from the surrounding environment by a layer of new rock. The result is that the area must start over on top of bare rock, or wait till cracks form letting growth to happen. Either way, it takes time for anything to grow.
Stages of Ecological Succession
Bare rock is considered Stage 1 in the ecological succession process. Stage 1 is where nothing can grow. Stage 1 is harsh and empty landscape…no green growing, and no animals actively visiting the site. Just bare stone throughout the landscape. The ecological value (that is how effective the land can support a diversity of life) is pretty much zero. Overtime with the right conditions, thin soil will form or things like moss that don’t need soil will start to grow. These small steps toward reestablishing the ecosystem are the beginning of Stage 2 in the succession process. Ecologists refer these organisms as pioneers. They will slowly build the soil up allowing for more biodiversity like birds, insects, grasses and the like to be attracted and to thrive. As these birds, insects and grasses appear, and the soil gets a little deeper, the area enters into Stage 3.
Stage 3 is usually where the forest fire scenario starts. The area will begin to support the proliferation of annual plants. A very familiar class of annuals homeowners know well is weeds. Nearly every weed you can bring to mind like crabgrass, lambquarters, bittercress and carpetweed are annuals. Many are also edible and all of them love harsh conditions and disturbed soils. Stage 3 is a wonderland of disturbed soil.
After Stage 3, the soil quality gets better allowing perennials and more complex types of grasses to grow. When these types of plants appear, you know you are in Stage 4 because perennials are essential for the stage. The ecological value of Stage 4 is worlds beyond Stage 3 with a much bigger list of plants and animals that can thrive within the stage. Also, the area may have places where lower stages exist, but these variations of stages provide the foundation for ecological niches and a wider variety of species.
The image to keep in mind for Stage 3 is a vacant lot where weeds have completely taken over. However, meadow full of wildflowers is what Stage 4 looks like. These two images highlight just how big an ecological step Stage 3 to Stage 4 is. It’s more like a giant leap.
After the Great Leap
Stage 5 is when shrubs and taller plants begin to overtake perennials. Stage 6 is when the area can support evergreens and other trees that are shade intolerant, are short-lived and don’t need super thick soil like aspen, alder and birch. Stage 7 (also referred to as the climax community) is when you get thick, hardwood deciduous forests that live hundreds (and thousands) of years. The ecological value of Stage 5 to 7 is much higher than the other stages. Some locations will never be able to support deep deciduous forests like the highlands of mountains where pine rein, or along the banks of fast flowing river, or in estuaries at the mouth of oceans, inlets and seas. It is how an area has all of these stages occupying different parts of it that truly gives nature its multitude of ecological niches and diversity. The infrastructure for nature’s beauty and sense of discovery is how ecological succession stages coexist. I think that is awesome.
Our Yards and the Natural World
Ok, but so what? Well, ecological succession really helps us to understand how an ecosystem regenerates after a disturbance. We, humans, have created a huge disturbance within the natural world, and the stages of ecological succession give us a way to determine how we can engage our yards and the world around us to assist in the process of regeneration. For me, it means I can actively help nature achieve more ecological value once I know where my yard currently is.
As I mentioned, ecological succession starts after a disruption. One example of a disruption is a forest fire. The fire burns down all trees, shrubs, grasses and other plants on the land. It also either kills any animals in the area or chases them away. What’s left is a scorched landscape blacked with ash.
Disturbance in the Force
Another type of disruption is when a much more devastating occurrence happens such as a volcanic eruption. In this case, lava flows over the landscape coating it with a thick layer of magma. It essentially does the same thing as the forest fire by killing everything in its path and/or chasing all the living things away. The difference is how each disruption interacts with the soil.
If you are a gardener or an avid landscaper, you know that soil is the root of all good things in your yard. If you have rich soil, your plants will be happy and healthy. If you have degraded soils, you get weak and unhappy plants. With a forest fire, everything burns but the soil is still connected to the surrounding environment.
With the lava, you have a completely different situation. When the magma cools, the soil is completely cut off from the surrounding environment by a layer of new rock. The result is that the area must start over on top of bare rock, or wait till cracks form letting growth to happen. Either way, it takes time for anything to grow.
Stages of Ecological Succession
Bare rock is considered Stage 1 in the ecological succession process. Stage 1 is where nothing can grow. Stage 1 is harsh and empty landscape…no green growing, and no animals actively visiting the site. Just bare stone throughout the landscape. The ecological value (that is how effective the land can support a diversity of life) is pretty much zero. Overtime with the right conditions, thin soil will form or things like moss that don’t need soil will start to grow. These small steps toward reestablishing the ecosystem are the beginning of Stage 2 in the succession process. Ecologists refer these organisms as pioneers. They will slowly build the soil up allowing for more biodiversity like birds, insects, grasses and the like to be attracted and to thrive. As these birds, insects and grasses appear, and the soil gets a little deeper, the area enters into Stage 3.
Stage 3 is usually where the forest fire scenario starts. The area will begin to support the proliferation of annual plants. A very familiar class of annuals homeowners know well is weeds. Nearly every weed you can bring to mind like crabgrass, lambquarters, bittercress and carpetweed are annuals. Many are also edible and all of them love harsh conditions and disturbed soils. Stage 3 is a wonderland of disturbed soil.
After Stage 3, the soil quality gets better allowing perennials and more complex types of grasses to grow. When these types of plants appear, you know you are in Stage 4 because perennials are essential for the stage. The ecological value of Stage 4 is worlds beyond Stage 3 with a much bigger list of plants and animals that can thrive within the stage. Also, the area may have places where lower stages exist, but these variations of stages provide the foundation for ecological niches and a wider variety of species.
The image to keep in mind for Stage 3 is a vacant lot where weeds have completely taken over. However, meadow full of wildflowers is what Stage 4 looks like. These two images highlight just how big an ecological step Stage 3 to Stage 4 is. It’s more like a giant leap.
After the Great Leap
Stage 5 is when shrubs and taller plants begin to overtake perennials. Stage 6 is when the area can support evergreens and other trees that are shade intolerant, are short-lived and don’t need super thick soil like aspen, alder and birch. Stage 7 (also referred to as the climax community) is when you get thick, hardwood deciduous forests that live hundreds (and thousands) of years. The ecological value of Stage 5 to 7 is much higher than the other stages. Some locations will never be able to support deep deciduous forests like the highlands of mountains where pine rein, or along the banks of fast flowing river, or in estuaries at the mouth of oceans, inlets and seas. It is how an area has all of these stages occupying different parts of it that truly gives nature its multitude of ecological niches and diversity. The infrastructure for nature’s beauty and sense of discovery is how ecological succession stages coexist. I think that is awesome.
Our Yards and the Natural World
Ok, but so what? Well, ecological succession really helps us to understand how an ecosystem regenerates after a disturbance. We, humans, have created a huge disturbance within the natural world, and the stages of ecological succession give us a way to determine how we can engage our yards and the world around us to assist in the process of regeneration. For me, it means I can actively help nature achieve more ecological value once I know where my yard currently is.
Let’s use an example for a normal suburban neighborhood. The image below shows a couple of yards with lawn, shrubs, trees, sidewalks, driveways and homes. So first, I want to identify Stage 1 areas in the picture below.
I’ve highlighted the areas that would easily fit into Stage 1 with red. All of the roadways, roofs and drives are acting essentially the same way as a layer of magma would. The asphalt of the roads, the concrete of the sidewalks and houses the rooftops are on completely separating the soil beneath them from the surrounding environment.
Only in the cracks and imperfections of the sidewalk or along the driveway are signs of Stage 2 development. I’ve indicated them with black circles below.
With residential properties, you have a strange hybrid of Stage 3 and 4. Our lawns are Stage 3 even though the grasses we plant like tall fescue and Kentucky bluegrass are perennials (highlighted in purple). These grasses only grow because we water them, amend them and coat them with toxic fertilizers & pesticides. Even the yards that eliminate chemical fertilizers from their yards still perpetually keep their lawns in a Stage 3 with regular mowing and edging. The positive is that when you eliminate chemicals, the soil will regenerate and build up a vast biodiversity able to support wildflowers, shrubs and even deciduous trees of later stages. But, we never let that happen…so they stay stuck in Stage 3.
In this example of suburbia, no Stage 4 areas exist even though Stage 4 has a huge potential for beauty with wildflowers and a long list of native perennials. Instead, only small areas of Stage 5 shrubs exist. These shrubs do offer some ecological value such as corridors for animals moving from place to place, but they aren’t functioning as best they could. Stage 6 and 7 are also present, but again only in spots with a tree here or there.
Leaping at Change
I don’t point this out to make things sound horrible. I see big opportunity here. With just a few changes in maintenance and better choice of plants, this suburban turfscape could leap into the next step in ecological succession. The higher complexity can increase both aesthetic and economic value (also known as curb appeal). In the image below I substituted the Stage 3 lawns with Stage 4 wildflowers and replaced the low-functional shrubs with a native superstar called spicebush. The change doesn’t turn the picture into a old growth forest, but it does take the area one more step forward.
Leaping at Change
I don’t point this out to make things sound horrible. I see big opportunity here. With just a few changes in maintenance and better choice of plants, this suburban turfscape could leap into the next step in ecological succession. The higher complexity can increase both aesthetic and economic value (also known as curb appeal). In the image below I substituted the Stage 3 lawns with Stage 4 wildflowers and replaced the low-functional shrubs with a native superstar called spicebush. The change doesn’t turn the picture into a old growth forest, but it does take the area one more step forward.
Sometimes when faced with the realities of ecological decay around the world, we want to change everything at once. But that notion to “fix” everything all at once is more of a human desire than a piece of ecological wisdom. Sometimes, the best way to make things better is to just help nature take the next step.
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