Succession is supposed to end somewhere. That end point is the climax community. But look out of the window in most of Europe and you will not see one, because we mow it, graze it, burn it and plough it. This page covers what a climax community is, why ecologists now argue about the idea, and what happens when succession is stopped part-way.
📘 What you need to know
A climax community is the final, stable stage of succession, in equilibrium with the local climate and soil.
It has high diversity, high biomass, well-adapted species, intense competition and net productivity close to zero.
The traditional idea of one predictable end point has been challenged: ecosystems are dynamic, chance events matter, and humans influence almost everywhere.
Alternative stable states mean the same starting point can end in different stable configurations depending on conditions and chance.
The Vera wood-pasture hypothesis argues that large grazing animals kept natural European landscapes as a mosaic of woodland and open ground, not closed forest.
A plagioclimax is a community held in a semi-stable state by continued human activity, such as grazing, mowing or burning.
What a climax community actually is
A climax community is where succession settles. The species present are the ones best suited to the local climate and soil, and no new group can arrive and displace them. Populations stay roughly stable, and the ecosystem is in balance.
What it looks like in practice:
The widest range of species the site can support, filling many narrow niches.
High biomass, most of it locked up in large, long-lived plants.
Intense competition for light, water and nutrients, so K-strategists dominate.
Net productivity near zero: energy captured is matched by energy respired.
Examples include mature temperate forests, tropical rainforests and, in drier climates, savanna or grassland.
Definition
Climax community = the community that persists at a site once succession has run its course under the local conditions
Why the idea is now argued over
The classic version says every site marches towards one predictable climax set by its climate. Modern ecology is less confident, for three reasons.
Ecosystems never stop changing. Trees fall, fires burn patches, climate itself shifts. Defining a permanent final stage is difficult when nothing sits still for long.
Chance matters. Which seeds happened to arrive first, whether a storm hit in year three, whether a disease swept through — all of these can send a site down a different path. Two identical patches can end up dominated by different trees.
Humans are everywhere. Agriculture, urbanisation, pollution and introduced species affect what can develop, so it is often impossible to say what the “natural” climax would have been.
This is where alternative stable states come in, and it links straight back to tipping points. An ecosystem can follow several pathways and settle in more than one stable configuration, depending on starting conditions and on chance events like fire or storms.
The Vera wood-pasture hypothesis
For a long time the assumed natural climax across lowland Europe was closed-canopy forest: unbroken tree cover from coast to coast. Frans Vera challenged that.
His argument is that large herbivores — aurochs, bison, wild horses, wild cattle — were once abundant, and their grazing and browsing would have stopped forests from closing up completely. The result would have been a shifting mosaic: groves of trees, thorny scrub protecting young saplings, and open grassy glades, all moving around over time.
If that is right, then herbivores play a far bigger part in shaping climax communities than the classic model allowed. The natural landscape was not one thing; it was a patchwork maintained by animals.
This matters for conservation. If you are restoring a landscape, the question of what “natural” looked like decides whether you plant trees or bring in grazing animals.
Plagioclimax: succession stopped part-way
When human activity diverts succession and then keeps it diverted, the community that results is a plagioclimax. It looks stable, and it can last for centuries, but it is only semi-stable: it is held there artificially, and it would change if we stopped.
Do not read “artificial” as “worthless”. Plagioclimax habitats often hold rare species that could not survive under a closed canopy, which is why conservation bodies pay to keep grazing them.
The three examples worth knowing
Overgrazing by livestock. Sheep and cattle eat tree seedlings as fast as they appear, so grassland or shrubland is maintained instead of woodland.
Removal of top predators. Where wolves or lions have been removed, deer and antelope populations grow unchecked. Heavy browsing then stops forests from regenerating, so the removal of a carnivore ends up changing the vegetation.
UK heathland. Kept open for centuries by grazing, cutting and burning. Stop managing it and it turns to birch scrub and then woodland within a few decades.
Notice how neatly the second example runs backwards through the food web: fewer predators, more herbivores, fewer young trees, no forest. If you can write a chain like that in an exam, you will pick up the “explain why” marks that most students miss.
Worked examples
WORKED EXAMPLE 1
Explain why UK heathland is described as a plagioclimax rather than a climax community. (3 marks)
Mark 1: what a climax would be here
The climate and soil could support woodland, so woodland is the natural climax for the site.
Mark 2: what is stopping it
Grazing, cutting and burning remove tree seedlings, so succession is diverted before woodland can develop.
Mark 3: why the label fits
The heath is stable only while that management continues, so it is a semi-stable state maintained by people rather than a true climax.
Human activity holds it short of the natural climaxIf management stopped, birch and pine would move in within about twenty years.
WORKED EXAMPLE 2
A national park removes its last large predators. Predict the effect on the vegetation over the following fifty years and explain your reasoning.
Step 1: the immediate effect
Without predation, the herbivore population grows well above its previous level.
Step 2: the effect on plants
Heavier browsing removes tree seedlings and saplings, so no new trees replace the old ones.
Step 3: the long-term outcome
As mature trees die they are not replaced, so woodland thins and the area shifts towards open grassland with lower diversity.
Loss of the predator diverts succession and simplifies the ecosystemThis is top-down control, and it is the reverse of what happened when wolves returned to Yellowstone.
WORKED EXAMPLE 3
“Every ecosystem has one predictable climax community.” Discuss this statement.
Point for the statement
Climate and soil do set real limits, so tundra will never become rainforest and the broad end point is predictable.
Point against: ecosystems are dynamic
They keep changing, so a permanent final stage is hard to define or observe.
Point against: chance and alternative stable states
Fires, storms and which species arrive first can send the same site to different stable outcomes.
Point against: people
Human management means much of the land is held in a plagioclimax, so the natural climax is often unknown.
Broadly predictable in type, but not a single fixed end point“Discuss” needs both sides and a judgement at the end. Do not just list facts.
💡 Exam tip
Define a climax community as being in equilibrium with the local climate and soil, not simply “the last stage”.
When you name a factor like grazing or fire, always say why it changes succession: what it does to biodiversity, competition or stability.
Use the word plagioclimax whenever human management holds a site back. It is a precise term and examiners look for it.
Keep one UK or local example ready — heathland, moorland or hay meadow all work.
For evaluation questions, mention alternative stable states and the Vera hypothesis as evidence that the classic model is too simple.
Link back to your other pages: climax communities are dominated by K-strategists and have net productivity near zero.
⚠ Common mix-up
Climax does not mean forest. In dry or cold climates the climax is grassland, scrub or tundra.
A plagioclimax is not a climax. It is held short of one by continued human activity.
Stable does not mean unchanging. A climax community still has births, deaths and gaps opening in the canopy.
An alternative stable state is not a plagioclimax. The first is a genuinely different stable configuration; the second needs constant management to stay put.
Vera is a hypothesis, not a fact. Present it as a challenge to the classic view, and say it is debated.
Assuming managed habitats are low value. Many plagioclimax habitats are among the richest we have and are protected for exactly that reason.
Up next: Population Ecology — carrying capacity, limiting factors and the curves that describe how populations grow and level off.
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