Glossary

• Abiotic

  Relating to a non-living feature of an ecosystem such as light intensity, precipitation, temperature, wind speed, or wind direction.
• Adaptation

  Any feature which makes an organism well suited to living in its environment.
• Biodiversity

  The variety of species and ecosystems on Earth and the ecological processes of which they are part. Can be further categorised as ecosystem diversity, species diversity, and genetic diversity.
• Biological Oxygen Demand

  A measure of the amount of dissolved oxygen used by aerobic micro-organisms when decomposing organic matter in water. Is measured in mg I-1 of oxygen consumed over a 5 day period at 20C.
• Biotic

  Relating to a living feature of an ecosystem, such as competition, food supply, disease and predation.
• Biotic Index

  A scale showing the quality of an environment based on the types of organisms which inhabit it.
• Capture-Mark-Recapture

  A method used in ecology to estimate the size of a population.
• Density

  The number of individuals of the same species present per unit area or unit volume.
• Dissolved Oxygen Concentration

  A measure of the amount of free oxygen dissolved in water, which can be used to determine the quality of water and assess its ability to support life.
• Distribution

  The manner in which a group is arranged geographically. Can change seasonally, in response to resource availability, and in response to other external factors.
• Ecosystem

  A natural biological unit made up of living and non-living parts.
• Diversity Index

  A measure of species diversity in a community or area. Takes relative species abundance into account and provides more information about community composition than simply species richness.
• Ecosystem Diversity

  The variation in habitats, living communities, and ecological processes in the living world.
• Frequency

  The chance of finding a species within a defined area. It is the number or percentage of samples in which a particular species occurs, and takes no account of density or distribution.
• Genetic Diversity

  The variety of genetic characteristics involved in the genetic makeup of a species.
• Interquartile Range

  A measure of the spread of data. Data are arranged in ascending order and then split equally into quarters. Interquartile range is the difference between the upper limit of the lowest quarter and the lower limit of the upper quarter.
• Lincoln Index

  A method of estimating population sizes of individual animal species using capture-mark-recapture.
• Percentage Cover

  A measure of the amount of cover of a particular species in a quadrat.
• Quadrat

  A frame enclosing a known unit area which is used to assess species abundance.
• Qualitative Data

  Descriptive data, can be used to prepare species lists.
• Quantitative Data

  Numerical data gathered through measuring or counted.
• Random Sampling

  Sampling where every individual in a population has an equal and independent chance of being selected.
• Relative Abundance

  How common or rare a species is relative to other species in a defined area or community. Is expressed as a percentage of the total number of organisms in the area.
• Reliability

  The extent to which an experiment, test, or measuring procedure yields the same results on repeated trails. For the data to be reliable, the variation across the values must be small.
• Simple Random Sampling

  Sampling where every individual in a population has an equal and independent chance of being selected, and the average sample should accurately represent the population.
• Simpsons Biodiversity Index

  A measure of diversity which takes into account the number of species present, plus the relative abundance of each species.
• Species

  A group of organisms that can interbreed to produce fertile offspring.
• Species Diversity

  A measure of the number of different species present in a given area, rather than the abundance of each species.
• Species Richness

  The number of species present in a sample or an area.
• Standard Deviation

  A measure used to quantify the amount of variation or spread of a set of data.
• Stratified Random Sampling

  Sampling where the population is divided into categories then a random sample is selected from each category. The size of each sample should be proportional to the size of each category within the population.
• Systematic Random Sampling

  Sampling where a starting point is randomly chosen, and then a regular pattern of sampling is used to collect the sample.
• Transect

  A method which investigates distribution of organisms in relation to a fixed area by recording all the species found at points or in a quadrat placed at certain intervals along a line.
• Validity

  Encompasses the entire experiment and establishes whether the data obtained meet all the requirements of the research method.
• Diversity Index

  A measure of species diversity in a community or area. Takes relative species abundance into account and provides more information about community composition than simply species richness.