Ecological succession is the gradual, orderly process by which a community of plants, animals and microbes changes over time in one place, as pioneer species move onto bare or disturbed ground and are later replaced by more complex communities, often ending in a mature forest or other stable community. In India it can be seen on a lichen-covered rock in the Western Ghats, in a farm field abandoned in the north-east hills, on the sand dunes of the Thar and in a silting village pond. Last reviewed on 3 November 2026, this guide explains how succession works, what its stages are and how it shapes Indian landscapes.
Nature is never static. A landslide scar on a Himalayan slope turns green within a few years, a cleared patch of forest fills with weeds and then with saplings, and a pond left alone gradually becomes a marsh and then dry land. Behind these changes lies a predictable pattern that ecologists have studied for more than a century, and it helps explain both how nature heals and why some landscapes need careful management to stay as they are.
Quick Facts
| Definition | The gradual replacement of one community by another over time at the same site |
|---|---|
| Two main kinds | Primary succession on bare ground, secondary succession after disturbance |
| First arrivals | Pioneer species such as lichens, mosses, hardy grasses and weeds |
| Intermediate stages | Called seral stages, with shifting mixes of grasses, shrubs and fast-growing trees |
| End point | Climax community, a relatively stable mature community suited to the local climate |
| Time scale | Years for weedy fields, decades to centuries for forests, longer for bare rock |
| Early ecologists | Henry Cowles studied dune succession, Frederic Clements developed the climax idea |
| Indian examples | Rock and lava, jhum fallows, cleared forests, Thar and coastal dunes, silting ponds |
Key Takeaways
- Ecological succession is the step-by-step change in a community over time, driven partly by the organisms themselves, which alter the soil, light and moisture around them.
- Primary succession starts on lifeless surfaces such as bare rock, lava, new sand or glacial debris, while secondary succession restarts where soil and seeds already exist, so it is much faster.
- Pioneer species are tough, fast-spreading organisms, and they gradually make the site more hospitable for later arrivals.
- The classic end stage, the climax community, is better seen today as a dynamic, shifting mosaic than as a fixed final state.
- Indian examples range from lichens on rock to the regrowth of abandoned shifting-cultivation plots and the filling of ponds and lakes.
- Fire, grazing, invasive plants and human use can halt or divert succession, which is why managers sometimes work with it and sometimes against it.
What are the main stages of ecological succession?
The main stages of ecological succession are colonisation by pioneer species, a series of intermediate communities, and a mature stable community, and each stage changes the environment in a way that favours the next. Ecologists call the whole sequence a sere and each step a seral stage.
First, hardy pioneer organisms arrive and establish themselves in difficult conditions. Next, they alter the site by adding organic matter, building soil, giving shade or fixing nitrogen. As conditions soften, more demanding species such as grasses, herbs and shrubs move in and often displace the pioneers. Eventually taller, longer-lived species such as trees take over and create their own microclimate with shade, humidity and leaf litter. At this late stage the community changes slowly and tends to be self-perpetuating, with its species regenerating beneath the existing canopy.
The process is not a straight line. Storms, fires, floods and human activity can reset any stage, which means a landscape is usually a patchwork of areas at different points in the sequence.
What is primary succession?
Primary succession is the colonisation of a place that has never had soil or life, or that has lost every trace of both, such as bare rock, fresh lava, newly formed sand, or the ground exposed as a glacier retreats. It is the slowest kind of succession because soil has to be created from scratch.
On a bare rock surface in India, the typical sequence begins with crustose lichens and bacteria, which release acids and cling to the rock. Over decades they help weather the surface and trap dust and organic matter. Foliose and fruticose lichens and then mosses follow, forming a thin mat that holds moisture and builds a pocket of primitive soil. Small herbs and grasses then root in the pockets, followed by shrubs, and eventually by trees if the climate allows. Rocky outcrops on the Deccan plateau, exposed laterite surfaces in the Konkan and the Western Ghats, and landslide scars in the Himalaya all show some stage of this sequence.
Volcanic and glacial landscapes provide natural laboratories. Barren Island in the Andaman Sea, India’s only active volcano, is an example of a place where eruptions repeatedly disturb the land and life must recolonise. In the Himalaya, retreating glaciers expose fresh moraine and rock debris where pioneer plants and microbes begin to colonise. The exact species and rates differ from place to place and are still being studied.
What is secondary succession?
Secondary succession is the regrowth of a community in a place where an earlier community has been removed or damaged but soil, seeds and roots remain, as after fire, flood, felling or farming. It is much faster than primary succession because the soil already exists and the seed bank is intact.
A typical sequence on an abandoned field starts with annual weeds in the first season or two, followed by perennial herbs and grasses, then shrubs and fast-growing pioneer trees, and finally slower-growing shade-tolerant forest trees. The rate depends on rainfall, soil quality, how intensively the land was used and whether seed sources and animals that disperse seeds are nearby.
India has abundant examples. After a forest fire, a landslide, a cyclone or clear-felling, the cleared ground is first colonised by grasses, herbs and light-loving trees. Because most of India’s land has been used by people for a long time, secondary succession is the more common form seen in the countryside.
The difference between the two is the starting point: primary succession begins where there is no soil, while secondary succession begins where soil and seeds are already present. This difference largely determines the speed and the pioneers involved.
| Feature | Primary succession | Secondary succession |
|---|---|---|
| Starting condition | Bare rock, lava, new sand, glacial debris | Disturbed land with soil, such as a burnt or abandoned field |
| Soil | Absent; must be formed | Present, with a seed bank |
| Pioneers | Lichens, mosses, bacteria | Weeds, grasses, fast-growing trees |
| Speed | Very slow, decades to centuries | Faster, years to decades |
| Indian example | Rock outcrop, volcanic surface, glacier moraine | Abandoned jhum plot, fire-hit forest, fallow field |
How do pioneer species prepare the ground for others?
Pioneer species prepare the ground by weathering rock, adding organic matter, stabilising loose surfaces and sometimes enriching the soil with nitrogen, which makes the site more habitable for later arrivals. Ecologists describe three broad ways this can happen.
In the facilitation model, early species improve conditions so later species can settle, as when lichens and mosses build soil. In the tolerance model, later species simply tolerate the leftover conditions and gradually outlast the early ones. In the inhibition model, early arrivals actually suppress newcomers, and succession advances only when they die or are removed. These ideas were set out by Joseph Connell and Ralph Slatyer in the 1970s, and real communities often show a mix of all three.
Nitrogen fixers are especially important. Many legumes and some trees, such as certain acacias and alders, host bacteria that convert atmospheric nitrogen into usable forms. In the poor soils of abandoned land, such plants speed regrowth. In the Himalaya, alder trees often colonise landslide scars for this reason.
What is a climax community, and does it really exist?
A climax community is the relatively stable, mature community that develops at the end of succession and is balanced with the local climate and soil, though modern ecologists treat it as a flexible concept rather than a fixed endpoint. The idea was developed by Frederic Clements early in the twentieth century, who saw a community as a kind of superorganism heading for a single predictable climax in each climate.
Later research suggested a more nuanced view. Communities respond to many factors including soil, topography, fire, grazing, storms and chance, so the same region can support several different stable states. Many ecosystems are never allowed to reach a final stage because disturbance keeps resetting them. The current view often emphasises a shifting mosaic, in which patches at different ages coexist across a landscape.
In Indian terms, the expected climax varies with climate: tropical wet evergreen forest in the high-rainfall Western Ghats and north-east, moist or dry deciduous forest in central India, thorn scrub in drier areas and alpine meadows or conifer forest in the Himalaya. Grassland and savanna in places such as the Terai and parts of the Deccan can be stable for long periods, but only because fire, floods and grazing hold back woody growth.
How does succession happen on abandoned shifting-cultivation fields?
Succession on abandoned shifting-cultivation fields, known as jhum in India’s north-east, is a classic case of secondary succession in which the forest regrows during a fallow period. After the crop is harvested and the plot is left, weeds and grasses take over in the first years, followed by bamboo, shrubs and fast-growing trees, and later by older forest species.
Jhum systems traditionally relied on long fallow cycles, often a decade or more, which gave the forest time to rebuild soil fertility and structure. When populations grow and fallow periods shorten, regrowth is cut back before the land has recovered, and soil quality, biodiversity and yields can decline. Fallow vegetation in the region is often dominated by bamboo and other fast colonisers, which can slow the return of the original tree species. Studies of jhum fallows show that the structure and species mix recover over time, though full recovery of forest diversity can take a long while.
This is one reason why forest regeneration programmes and conservation planning in the north-east pay close attention to fallow length and community practices.
How does a pond or lake gradually turn into land?
A pond or lake gradually turns into land through hydrarch succession, in which silt and plant matter slowly fill the basin and a sequence of water-loving communities replaces one another. It is the standard Indian textbook example of succession in a wetland.
The stages usually run as follows. Phytoplankton and microbes colonise first, then submerged plants such as hydrilla and vallisneria take root, trapping silt and raising the bed. Rooted floating plants such as lotus, water lily and water chestnut follow, shading out the submerged plants. Next come reed-swamp plants such as cattails and reeds, which grow in shallow water and add large amounts of litter. Sedges and grasses form a marsh or meadow as the ground rises above water, and finally shrubs and trees move in on drying soil.
Natural lakes can take centuries or millennia to fill, but human activity can accelerate the process. Sewage, fertiliser runoff and soil washed in from deforested catchments increase nutrients and silt, speeding up weed growth and shrinking the lake. Many urban lakes and wetland edges across India are losing area this way, along with encroachment.
How does succession work on sand dunes?
Succession on sand dunes begins with salt-tolerant or drought-tolerant grasses and creepers that bind the loose sand, and it proceeds to shrubs and eventually to woodland if the dune stays stable. The process is called psammosere, and the American ecologist Henry Cowles famously studied it in the early 1900s.
On India’s coasts, pioneer creepers such as beach morning glory (Ipomoea pes-caprae) and hardy grasses colonise the upper beach and the front of the dune, trapping blown sand. Behind them come shrubs and then trees such as casuarina and cashew, which are often planted to hold dunes in place, and coconut groves on stable sandy strips. In the Thar Desert, plants such as sewan grass, phog and the khejri tree stabilise sandy ground and hold back moving dunes, though many Thar dunes remain active because of low rainfall, strong summer winds and heavy grazing. Over-grazing and removal of vegetation can reactivate dunes, which is why dune stabilisation and shelterbelt planting are major land-management efforts in Rajasthan and Gujarat.
How do mangroves and new land show succession?
Mangroves show succession as pioneer species colonise new mud and silt in river mouths, trap sediment and gradually extend land seaward, creating zones of different species. This process can be seen in deltas such as the Sundarbans, Bhitarkanika and the Godavari and Krishna deltas.
Species such as Avicennia, which tolerate the harshest salt and tidal conditions, tend to colonise the newest mud flats. Their roots trap sediment, building up the soil level. As the ground rises and becomes less flooded, other species such as Rhizophora, Bruguiera and Ceriops can take hold in the higher, less frequently flooded zones. The zonation seen in many mangroves reflects both tolerance to salt and flooding and the history of land building. Cyclones, erosion, rising sea level and human clearing can reverse these gains, so mangrove succession is a good example of the contest between building and destruction.
Can succession be stopped or steered?
Yes, succession can be halted, delayed or redirected by repeated disturbance, and managers sometimes use this on purpose to maintain particular habitats. Grasslands, for example, are often arrested stages that would turn to woodland without fire, grazing or flooding.
Kaziranga’s tall grasslands rely on annual floods and controlled burning to keep woody plants in check, which in turn supports rhinoceros, swamp deer and other grassland specialists. The wetlands of Keoladeo National Park and the Banni grassland in Gujarat have faced spread of invasive woody plants, especially Prosopis juliflora, which suppress grass and change habitat. Lantana is a similar problem in many forests, forming thickets that can block the return of native trees and so divert succession. In the other direction, restoration ecologists try to speed succession by planting pioneer trees, removing invasive plants, protecting regrowth from fire and livestock, and encouraging seed-dispersing animals.
Why does ecological succession matter for people and conservation?
Ecological succession matters because it explains how land recovers after damage, informs restoration and afforestation, and helps managers decide when to protect, when to intervene and when to leave nature alone. It also provides a reality check for planting programmes.
Understanding succession shows that restoring a forest is not the same as planting trees. A plantation of one species is an early, simplified stage and lacks the layers, animals and soil life of a natural forest. Natural regeneration, with or without help, tends to rebuild a richer community, and the right choice depends on how degraded the site is and whether seeds and dispersers are nearby. Succession also underpins the management of mine spoil, road cuttings, landslide scars and fire-hit forests, where pioneer planting can stabilise land.
At a larger scale, succession shows how forests store carbon: young regrowing forests absorb carbon rapidly, while older forests hold big stocks. This is relevant for India’s afforestation and carbon-sink goals, though the details vary by forest type and are an active area of research.
Bottom Line
Ecological succession is nature’s repair and renewal process. From lichens on a rock to a canopy forest, each stage prepares the way for the next, with the speed set by whether soil and seeds already exist. In India, where land is constantly reshaped by monsoon, fire, farming and development, understanding succession is the key to restoring ecosystems wisely.
Frequently Asked Questions
What is ecological succession in simple words?
Ecological succession is the gradual, step-by-step change in the plants and animals living in a place over time. Simple pioneers arrive first and are later replaced by more complex communities, often ending in a mature forest.
What is the difference between primary and secondary succession?
Primary succession begins on bare ground with no soil, such as rock or lava, and is very slow. Secondary succession begins where soil and seeds remain after a disturbance, such as an abandoned field, and is much faster.
What are pioneer species?
Pioneer species are the hardy first organisms to colonise bare or disturbed ground, such as lichens, mosses, weeds and certain grasses. They improve the soil and conditions for later species.
What is a climax community?
A climax community is the relatively stable, mature community that develops at the end of succession and suits the local climate. Today ecologists see it as a flexible, shifting mosaic rather than a fixed final state.
How long does ecological succession take?
It depends on the starting point: weedy fields can change within a few years, regrowing forests take decades to centuries, and primary succession on bare rock can take far longer. Climate, soil and available seeds all affect the speed.
Can succession be prevented?
Yes, repeated disturbance such as fire, grazing, flooding or invasive plants can hold a community at an early stage. Managers sometimes use this deliberately to keep grasslands open for wildlife.
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