Ecosystem Structure and Function — Core Concepts

Core Concepts

System map

Place the physical environment beside the living components, then connect them with arrows for energy and material transfers. State the boundary: pond, forest patch or catchment. Inputs and outputs depend on that boundary.

Structure

Species composition: which organisms occur.
Spatial arrangement: where they occur, including vertical layers.
Abiotic setting: light, water, temperature, sediment and dissolved substances.

Function

Production creates organic material.
Consumption transfers material through feeding.
Decomposition processes dead matter and wastes.
Nutrient transformations and movement connect organisms with soil, water and air.

Accounting distinctions

Standing crop is a stock at a time. Productivity is a rate and requires a time unit. Net primary productivity equals gross primary productivity minus producer respiration. Keep the same area, period and units when calculating.

Energy is transferred and dissipated through biological activity; nutrient elements can be reused after transformation. Decomposers therefore do not recycle energy back to its original usable supply.

Assessment framework

Pressure → affected component → altered process → consequence → response → indicator. Tree counts, species lists and photographs are useful structural observations but do not alone demonstrate every ecosystem function. Check both the immediate response and recovery over time. Use a clearly defined baseline and avoid judging all ecosystems by one universal target value or a single visual indicator.