PAGE 15 / 102

Unit 1: Basic Ecological Concepts and Principles Related to Agricultural Systems

Principle 1: Ecosystem characteristics are determined by place.

Local environmental factors strongly affect ecological processes, and the number and distribution of plants, animals and other organisms in a particular area. When discussing an ecosystem’s structure – its physical parts – ecologists often refer to biotic and abiotic factors: the living and non-living components that make up an ecosystem. Biotic and abiotic factors interact with and influence each other, thus determining the characteristics of an ecosystem that develop over time. However, it is the abiotic factors associated with ‘place’ that really determine the context or constraints that we have to work within.

Examples of abiotic factors include:

• Climate: temperature, rainfall, light, wind, fire, seasonal changes

• Geomorphology: soil type, rocks, organic matter

• Hydrology: lakes, rivers and streams