Open navigation menu
Biology
Lưới thức ăn và biến động hệ sinh thái
Loading resource…
Loading resource…
Change a hypothetical grassland food web and compare biomass dynamics with a control at the same time.
Press Run, follow the rabbits →Food → consumer
Thicker arrows = more food transferred · ┄ no food flow
Thicker arrows = more food transferred · ┄ no food flow
The hawk is removed. Run and follow the rabbits; then select grass or frogs to explore indirect effects.
Edit food sources · Rabbit
Toggle food sources for the selected consumer. Only predefined plausible feeding relations are available.
Grass growth
Multiplier of grass regeneration rate; 1× is the initial condition.
Harvest rate · Rabbit 0%
0% · Continuous removal rate on current biomass per model time unit. For example, 20% means a coefficient of 0.2, not exactly 20% removed after one step.
Primary consumer (herbivore)
Model time:
- Intervention
- Control
% of initial biomass
Difference: 0 percentage points
Control from t = 0.0
About comparison points
Copy the current state and conditions to the control; clear previous curves and keep the current time.
Time (model units)
━ Intervention┄ Control · Rabbit
┆ Intervention times. Latest intervention: t = 0.0
Increasing tendency
percentage points / model time unit
Why does biomass change?
- Gain from food
- +26.2
- Loss to consumers
- 0
- Natural losses
- -16.2
- Harvest loss
- 0
Instantaneous rates relative to this group's initial biomass; values are rounded. These are not fixed changes over the next step: the rates also change as the ecosystem evolves.
Interpret the result
Removing the hawk reduces predation on its prey. Indirect effects can reach grass; the direction and magnitude depend on the whole web.
Biomass by group
| Group | Intervention | Control |
|---|---|---|
| 100% | 100% | |
| 100% | 100% | |
| 100% | 100% | |
| 100% | 100% | |
| 100% | 100% | |
| 0% | 100% |
100% = each group's initial biomass. Bar: 0–200%; middle tick = 100%. Circle area follows the percentage of its own baseline, capped at 250%; it does not compare mass across groups.
Model notes
- A hypothetical grassland with six representative groups. The feeding relations illustrate principles; they do not describe a specific site or biological species.
- A continuous biomass model: producer growth is limited, consumers have saturating feeding rates, convert part of their food and experience losses. Parameters are illustrative, not fitted to field data.
- 100% is the initial biomass of each group separately; groups do not start with equal biomass. Icons do not count individuals. Time uses model units, not real days or weeks.
- Removal sets biomass to zero, with no spontaneous return. Reintroduction adds 20% of initial biomass. A very small positive biomass does not mean extinction.
- The control starts from the same state at the comparison point and retains those conditions. Changes to the experimental food web or parameters do not alter it.
- Age, space, seasons, migration, random extinction, decomposition and nutrient cycling are omitted. Conversion is not a fixed 10% rule. Results cannot support field forecasts or management decisions.