Abiotic factors are the non-living factors that can affect a community. They are light intensity, temperature, moisture levels, soil pH and mineral content, wind intensity and direction, carbon dioxide levels for plants, and oxygen levels for aquatic animals.
A change in one abiotic factor can change which organisms can survive in a habitat. For example, less light reduces the rate of photosynthesis, so plants grow more slowly and make less food. Fewer plants means less food and shelter for the animals that depend on them, so the whole community can change.
Low oxygen levels in a pond, perhaps after pollution, mean fish and other aquatic animals cannot get enough oxygen for respiration, so their numbers fall. A drop in soil pH or mineral content can stop some plants growing. A sudden rise in temperature or a drought that lowers moisture levels can also cause some species to die out or move away.
When you are given a chart, graph or table, look for how the number of organisms changes as the abiotic factor changes, then explain the link using what the organism needs to survive.