Tundra food web examples with 20 organisms
The tundra biome has a short growing season, low temperatures, and nutrient cycling strongly influenced by slow decomposition. A useful way to study these constraints is to build tundra food web examples with 20 organisms, separating them into producers, primary consumers, predators/scavengers, and decomposers, then mapping arrows from resource to consumer.
Step 1: List 20 tundra organisms and assign trophic roles
The list below provides one coherent tundra community containing exactly 20 organisms (taxa), including a decomposer pathway.
| # | Organism | Role in the tundra food web | Typical food source (examples) |
|---|---|---|---|
| 1 | Reindeer lichen (Cladonia spp.) | Producer | Photosynthesis |
| 2 | Sphagnum moss (Sphagnum spp.) | Producer | Photosynthesis |
| 3 | Arctic willow (Salix arctica) | Producer | Photosynthesis |
| 4 | Dwarf birch (Betula nana) | Producer | Photosynthesis |
| 5 | Cotton grass (Eriophorum spp.) | Producer | Photosynthesis |
| 6 | Caribou (Rangifer tarandus) | Primary consumer | Lichens, sedges, willow leaves |
| 7 | Musk ox (Ovibos moschatus) | Primary consumer | Sedges, grasses, willow twigs |
| 8 | Arctic hare (Lepus arcticus) | Primary consumer | Willow, dwarf birch, grasses |
| 9 | Collared lemming (Dicrostonyx spp.) | Primary consumer | Mosses, sedges, grasses |
| 10 | Rock ptarmigan (Lagopus muta) | Primary consumer / omnivore | Willow/birch buds, seeds, some insects |
| 11 | Tundra mosquito (Aedes spp.) | Primary consumer / detritus-linked | Nectar (adult); organic detritus (larvae) |
| 12 | Arctic bumblebee (Bombus spp.) | Primary consumer | Nectar and pollen |
| 13 | Ermine / stoat (Mustela erminea) | Secondary consumer | Lemmings, small birds |
| 14 | Long-tailed jaeger (Stercorarius longicaudus) | Secondary consumer | Lemmings, eggs/chicks, insects |
| 15 | Snowy owl (Bubo scandiacus) | Secondary consumer | Lemmings, ptarmigan |
| 16 | Arctic fox (Vulpes lagopus) | Secondary consumer / scavenger | Lemmings, hare, birds, carrion |
| 17 | Gray wolf (Canis lupus) | Tertiary consumer | Caribou, musk ox (often calves/weakened) |
| 18 | Common raven (Corvus corax) | Scavenger / omnivore | Carrion, eggs, insects, scraps |
| 19 | Soil fungi (saprotrophic fungi) | Decomposer | Dead plant/animal material |
| 20 | Soil bacteria | Decomposer | Dead organic matter; nutrient recycling |
Step 2: Create feeding links (resource → consumer)
A food web is a network of many feeding links. Arrows are drawn from what is eaten (resource) to the organism that eats it (consumer). The links below are representative and sufficient to form a connected tundra web with multiple pathways.
| Feeding link (resource → consumer) | Ecological meaning |
|---|---|
| Reindeer lichen → Caribou | Classic tundra grazing pathway |
| Arctic willow → Caribou | Seasonal browsing |
| Cotton grass → Caribou | Sedge/grass consumption in summer |
| Cotton grass → Musk ox | Grazing on sedges and grasses |
| Arctic willow → Musk ox | Browsing on woody plant tissue |
| Arctic willow → Arctic hare | Winter browsing on twigs/bark |
| Dwarf birch → Arctic hare | Browsing on buds and leaves |
| Sphagnum moss → Collared lemming | Small herbivore pathway |
| Cotton grass → Collared lemming | Sedge consumption |
| Arctic willow → Rock ptarmigan | Bud/leaf feeding |
| Dwarf birch → Rock ptarmigan | Bud/seed feeding |
| Tundra mosquito → Rock ptarmigan | Seasonal insect intake |
| Arctic willow → Arctic bumblebee | Nectar/pollen pathway |
| Dwarf birch → Arctic bumblebee | Nectar/pollen pathway |
| Collared lemming → Ermine | Specialized small-mammal predation |
| Rock ptarmigan (eggs/chicks) → Ermine | Nest predation when available |
| Collared lemming → Long-tailed jaeger | Key tundra predator–prey link |
| Tundra mosquito → Long-tailed jaeger | Insect supplementation |
| Collared lemming → Snowy owl | Core prey supporting owl breeding |
| Rock ptarmigan → Snowy owl | Alternative prey |
| Collared lemming → Arctic fox | Common predation pathway |
| Arctic hare → Arctic fox | Predation/scavenging depending on conditions |
| Rock ptarmigan → Arctic fox | Bird predation |
| Caribou → Gray wolf | Top-predator control on large herbivores |
| Musk ox → Gray wolf | Opportunistic predation (often calves) |
| Caribou (carrion) → Common raven | Scavenger link that accelerates energy recycling |
| Arctic hare (carrion) → Common raven | Scavenger link |
| Dead organic matter → Soil fungi | Decomposition and nutrient recycling |
| Dead organic matter → Soil bacteria | Decomposition and nutrient recycling |
Step 3: Interpret the web using trophic transfer
Trophic transfer describes how energy and biomass move from producers to higher trophic levels. A commonly used approximation is that only about \(10\%\) of energy is transferred from one trophic level to the next (the rest is lost as heat, movement, and metabolic work).
If net primary production available to herbivores is \(10\,000\ \mathrm{kJ\ m^{-2}\ yr^{-1}}\), then an approximate energy budget is:
\[ \text{Primary consumers} \approx 0.10 \times 10\,000 = 1\,000\ \mathrm{kJ\ m^{-2}\ yr^{-1}} \] \[ \text{Secondary consumers} \approx 0.10 \times 1\,000 = 100\ \mathrm{kJ\ m^{-2}\ yr^{-1}} \] \[ \text{Tertiary consumers} \approx 0.10 \times 100 = 10\ \mathrm{kJ\ m^{-2}\ yr^{-1}} \]
This steep decline helps explain why tundra food webs support many producers and fewer top predators, and why predators such as snowy owls and arctic foxes respond strongly to lemming population cycles.
Visualization: a tundra food web network (20 organisms)
Step 4: Questions the web can answer
A tundra food web built from 20 organisms makes it possible to predict indirect effects. For example, a decline in collared lemmings can reduce energy flow to snowy owls, jaegers, and arctic foxes, often increasing predation pressure on alternative prey such as ptarmigan. Likewise, changes in decomposition rates can shift nutrient availability, altering producer biomass at the base of the web.