The very first plants to grow during primary succession are almost always non-vascular pioneers: lichens, mosses, cyanobacteria (blue-green algae), and algae. These pioneers are often described as plants that grow naturally in succession on bare ground, and they provide the early cover the ecosystem needs The very first plants to grow. These colonize bare rock or fresh mineral substrate before any true flowering plant can get a foothold. Once they break down surface material and build even a thin organic layer, the first vascular plants move in. Depending on your climate, those tend to be hardy grasses, sedges, fireweed, dryas, willows, or coastal annuals like sea rocket. The exact lineup changes a lot based on where you are, what the substrate looks like, and what time of year it is.
Which Plants Grow First in Primary Succession by Climate
What primary succession actually means and what counts as bare ground
Primary succession starts from zero. Not 'disturbed and recovering' zero, but genuinely barren substrate with no soil, no seed bank, and no organic matter. The classic examples are fresh lava flows (USGS describes new volcanic substrate as 'barren and sterile'), land exposed by a retreating glacier, newly uplifted coastal rock, and freshly deposited sand dunes or riverbars. Surtsey, the volcanic island that erupted off Iceland in 1963, is a textbook case: by May 1964, scientists were already observing the very first biological colonizers arriving on completely new rock.
This is different from secondary succession, where a wildfire, hurricane, or logging operation resets an existing plant community but leaves soil and often a seed bank behind. Secondary succession moves faster because the soil foundation is already there. If you're wondering what plants come back after a fire, that's a different process with a very different starting cast. Primary succession is the slower, harder process of building an ecosystem from scratch.
The real first colonizers: lichens, mosses, and biological soil crusts
Before any plant you'd recognize from a garden center shows up, the surface gets colonized by organisms most people overlook entirely. Lichens (a fungus-algae partnership) attach directly to bare rock and begin chemically weathering it. Mosses follow, holding moisture and trapping wind-blown mineral particles. In drier regions especially, cyanobacteria dominate what ecologists call biological soil crusts or 'biocrusts': thin photosynthetic assemblages living in the top few millimeters of the soil surface. Genera like Microcoleus, Schizothrix, and Coleofasciculus are often among the very first photosynthetic colonizers on bare mineral ground in those systems.
These early colonizers do two things that make everything else possible. First, cyanobacteria and cyanolichens fix atmospheric nitrogen, pulling it from the air and converting it into organic compounds that later plants can actually use. Second, their filamentous biomass physically binds loose soil particles together, stabilizing the surface so wind and rain don't just strip it bare again. At Glacier Bay in Alaska, the NPS describes lichens attaching to exposed rock as the first visible stage of a succession sequence that eventually leads to Sitka spruce forest. The same logic applies whether you're standing on a lava field in Hawaii, a desert pavement in Utah, or a glacial moraine in the Alps.
One thing worth knowing: biocrusts are fragile and extremely slow to recover once damaged. In very dry environments, some lichen and algal components can take several hundred years to fully recover from disturbance. That's important context if you're trying to identify or study them in the field. Stay on bare rock or established paths rather than stepping on that dark, slightly lumpy surface crust.
The first vascular plants: what shows up after the pioneers do their work
Once lichens and mosses have built even a thin organic layer, vascular plants can begin establishing. These early vascular pioneers share a common profile: small, wind-dispersed seeds, tolerance for nutrient-poor and often dry or wet-extreme conditions, and root systems that can handle minimal soil depth. You'll see a handful of genera appear again and again across very different landscapes.
At Glacier Bay and Kenai Fjords, NPS records show fireweed (Chamerion angustifolium / Chamerion latifolium) appearing in thin soils shortly after the lichen-moss stage. blank" rel="noopener noreferrer">Yellow dryas (Dryas drummondii) spreads from seed on exposed sand and silt wherever conditions allow it to catch hold. Arctic willow (Salix arctica) and feltleaf willow (Salix alaxensis) colonize newly exposed gravel, riverbars, and recently deglaciated sites. blank" rel="noopener noreferrer">A Canadian High Arctic study on bare moraine found Epilobium latifolium and Salix arctica as the two dominant pioneer vascular species. On Surtsey Island, the first confirmed vascular plant seedlings (spotted in 1965) were sea rocket (Cakile maritima subsp. islandica), followed shortly by sand ryegrass (Leymus arenarius), oysterleaf (Mertensia maritima), and seaside sandplant (Honckenya peploides), all coastal specialists suited to the island's exposed conditions.
Nitrogen-fixing shrubs deserve a special mention here. Sitka alder (Alnus crispa) and species like Dryas fix atmospheric nitrogen through root symbioses, meaning they can push into lean soils that would starve most other plants. At Glacier Bay, studies show that alders and dryas derive most of their nitrogen from atmospheric fixation rather than soil, which explains why they appear so early in the sequence despite the nutrient-poor substrate.
How pioneer plants differ across climate zones and seasons
The general sequence (microbes/cyanobacteria, then lichens/mosses, then early vascular plants) holds across most environments. But which specific plants fill each role shifts considerably depending on where you are. Season matters too: a site exposed in late autumn in a temperate zone may sit dormant all winter before the first colonizers arrive in spring, while a tropical lava flow can see biological crusts forming within months.
| Climate Zone / Biome | First Non-Vascular Colonizers | First Vascular Pioneers | Notes on Timing |
|---|---|---|---|
| Arctic / High Arctic | Cyanobacteria, crustose lichens, mosses | Epilobium latifolium, Salix arctica, Dryas octopetala | Very slow; meaningful succession visible over decades to centuries |
| Boreal / Subarctic (Alaska) | Lichens, mosses | Fireweed (Chamerion angustifolium), feltleaf willow (Salix alaxensis), Sitka alder | Glacial retreat sites; willows on riverbars can establish within years |
| Temperate Alpine | Crustose lichens, mosses, algal films | Grasses, sedges, early forbs (site-dependent) | Moss cover and soil aeration are key predictors of when vascular plants appear |
| Mediterranean | Cyanobacteria-dominated biocrusts, lichens | Hemicryptophyte grasses, annual forbs on roadcuts and eroded slopes | Younger disturbed sites favor grasses; composition shifts with age over 30+ years |
| Desert / Dryland | Cyanobacteria (Microcoleus dominant), cyanolichens, algae | Drought-tolerant annuals, sparse perennial grasses | Biocrust recovery can take hundreds of years; vascular pioneers very sparse early |
| Coastal / Island | Algae, biofilms, salt-tolerant lichens | Sea rocket (Cakile spp.), sand ryegrass (Leymus arenarius), sandwort (Honckenya peploides) | Seeds often arrive by ocean currents; colonization can be rapid on exposed beaches |
In the Arctic, an ongoing chronosequence study in the Brooks Range found that after 22 to 36 years following deglaciation, early communities typically contain just 8 to 13 vascular and nonvascular plant species, and many pioneer taxa (especially lichens) persist across even the oldest sites in the sequence. Succession here is genuinely slow, unfolding over tens of thousands of years. Mediterranean roadcuts show a faster but still directional process: younger cuts are dominated by certain hemicryptophyte grasses that progressively get replaced as the site ages. Same principle, very different timescale.
Site conditions that decide which plants arrive first
Beyond climate zone, several on-the-ground factors determine which pioneers show up and how fast succession moves. An alpine glacier-foreland study found that total ground cover, moss cover, soil aeration, temperature, and time since deglaciation were the most tightly correlated variables in predicting where and when vascular plants appeared. In practical terms, that translates into a handful of things you can actually observe and assess at a site.
- Substrate type: bare solid rock weathers slowly and gets lichens first; sand, silt, and gravel allow moss and cyanobacteria to establish faster and vascular plants to root sooner
- Moisture availability: a moist, sheltered crevice in rock will develop moss and fern colonizers much faster than a dry exposed face
- Sunlight exposure: full-sun bare surfaces heat up and dry out, pushing succession toward drought-tolerant crust communities; shaded sites favor early mosses and shade-tolerant ferns
- Nitrogen status: sites with no prior nitrogen input start slower; nitrogen-fixing pioneers (cyanobacteria, cyanolichens, alder, dryas) are the most valuable early colonizers in these situations
- Seed source proximity: even if conditions are perfect, pioneer vascular plants can't arrive without a nearby seed source or wind/water dispersal pathway; coastal sites get sea-rocket seeds from ocean drift while inland glacial sites depend on wind
- Disturbance history and timing: a site exposed in spring in a temperate zone will develop very differently than one exposed in late summer, because the first growing season determines which early colonizers establish
These factors interact. A moist sandy substrate near a seed source in a temperate climate can have visible vascular plant cover within a single growing season. A dry exposed slab of granite on a high-elevation ridge in the same region might take decades just to accumulate enough lichen biomass for mosses to follow. Reading those site conditions before assuming what 'should' be there is the first step toward understanding (or supporting) succession at any specific location.
How to spot pioneer plants in the field and what to do next
If you're trying to observe or support primary succession, the first thing to do is get your eyes close to the surface. Biocrusts look like a dark, slightly raised or lumpy crust on bare soil or rock, sometimes with a greenish or blackish tinge. On rock faces, look for thin paint-like patches of color (crustose lichens) before you look for anything leafy. In moist crevices, look for small cushions of moss. These are your indicators that succession has begun, and they're often missed because people scan the horizon for visible plants.
For identifying likely vascular pioneers in your area, work from your climate zone and substrate type outward. In coastal temperate zones, check for Cakile (sea rocket) on exposed sand and Leymus (sand ryegrass) on established dunes. In boreal and subarctic zones, look for fireweed on disturbed mineral soil and feltleaf willow on recently exposed riverbars. In alpine and arctic zones, Dryas species, Epilobium, and early Salix are the names to know. In Mediterranean systems on disturbed slopes or roadcuts, early hemicryptophyte grasses are typically what moves in first at the vascular plant stage.
If you're trying to actively support or initiate succession on a bare site, a few practical points apply. Don't skip the crust stage: if you're working in a dryland or semi-arid context, trying to establish vascular plants before any soil structure exists will mostly fail. Focus first on conditions that allow cyanobacteria and lichen colonization (reduced foot traffic, minimal soil disturbance, patience). In wetter climates, introducing native mosses into moist crevices can accelerate the early stage significantly. For the vascular plant phase, choose species that match both your climate zone and the specific substrate: nitrogen-fixers like alder, dryas, or native legumes on nutrient-poor substrates; wind-dispersed annuals and grasses on exposed, open ground with some moisture. Avoid the temptation to jump straight to mid-successional species from a native plant nursery: those plants need the organic matter and nutrients that only the pioneers can build.
One pattern worth noting across all these systems: the plants that grow on dead and decaying organic matter become relevant just a step after the very earliest pioneers, as the first biological crusts die back and create the first pockets of organic material on what was bare rock. Plants that grow on dead and decaying matter are called detritivores or saprobes depending on how they feed. Similarly, the wind-dispersed seedlings that arrive in that thin early soil layer are technically the first new plants growing from seeds in a genuinely new habitat, which is a remarkable thing to witness up close if you get the chance. Watching that whole sequence play out, even on a small roadcut or a rock face near a receding alpine snowfield, makes the abstract idea of ecosystem assembly feel very concrete. The first plants to grow after a fire are called fire followers, and they’re adapted to the nutrient and light conditions created by burning.
FAQ
Do flowering plants ever appear first in primary succession?
Usually not. In true primary succession, the first visible colonizers are non-vascular, like lichens and mosses, because vascular plants need at least a thin organic layer. Flowering plants typically arrive after that early biological crust stabilizes the surface.
Are “first” plants the same everywhere, or does the list change by climate?
The overall order is consistent, microbes and cyanobacteria, then lichens and mosses, then early vascular pioneers. But which specific vascular species dominate can shift dramatically with temperature range, rainfall, and season length, even on similarly bare substrates.
What’s the earliest sign that primary succession has started if there are no green plants yet?
Look for thin, crust-like color patches on rock, often paint-like lichens, and for dark or greenish slightly lumpy surfaces that indicate biological soil crust. These can be present long before any leafy moss cushions or grass-like growth is obvious.
How long does it take before grasses or other vascular plants show up?
It varies widely. In some moist areas, vascular cover can appear within a single growing season once a thin organic layer forms, but in exposed, dry or high-elevation conditions it may take decades to build enough lichens and moss to support vascular seedlings.
Why do cyanobacteria and lichens matter so much at the beginning?
Beyond being early colonizers, many are nitrogen fixers, and they physically bind mineral particles together. That combination creates usable nutrients and a more stable surface that reduces erosion and lets vascular roots gain a foothold.
Can disturbance wipe out the early stage, and does it bounce back quickly?
Early biocrusts are fragile. In many dry environments, recovery after trampling or scraping can take hundreds of years, so repeated foot traffic near the crust can prevent succession from progressing to the vascular plant stage.
What if seeds are already present on the bare ground, why doesn’t vascular growth start immediately?
Seeds alone do not guarantee establishment. Early succession sites often have no soil structure, very low nutrients, and extreme moisture swings. Seedlings still need microhabitats created by crust-formers, which is why vascular pioneers tend to appear only after lichens and mosses build enough organic material.
Do nitrogen-fixing shrubs always appear early in primary succession?
They commonly show up early when conditions permit, especially on nutrient-poor substrates. However, their timing depends on the specific site factors like moisture, available microsites for rooting, and whether suitable symbiont conditions are met.
How do you distinguish primary succession from secondary succession when looking at a site?
The key cue is the substrate history. Primary succession starts on genuinely barren ground with no soil and no established seed bank, such as fresh lava or newly exposed glacial rock. Secondary succession is faster because soil and many seeds already remain, even if aboveground plants were removed.