2.1 a/b - field techniques

• risk assessments monitor the risk, hazard and control
• Hazards in fieldwork include adverse weather conditions, difficult terrain, problems with isolation, and contact with harmful organisms
• risk is the likelihood of harm arising from exposure to a hazard
• risk assessment identifies the control measures to minimise a risk
• controls measures include appropriate equipment, clothing, footwear, and means of communication
• sampling should be carried out in a way that minimises impact on wild species and habitats
• considerations must be given to rare and vulnerable species and habitats that are protected by legislation
• the chosen technique, point count, transect, or remote detection must be appropriate to the species being sampled
• a point count involves the observer recording all individuals seen from a fixed point count location
• capture techniques, like traps and nets, are used for mobile species
• elusive species can be sampled directly using camera traps or an indirect method, such as scat trampling
• the extent of natural selection within a population determines the appropriate sample size
• more variable populations requires require a larger sample size
• a representative sample should share the same mean and the same degree of variation about the mean of the population as a whole
• in animal studies the concepts of replacement, reduction and refinement are used to avoid, reduce or minimise the harm to animals
• quadrats of suitable size and shape are used for sessile and slow moving organisms
• stratified sampling

  when the population being sampled is split into sub populations
• systematic populations

  selecting a fixed starting point in the larger population and then obtaining subsequent observations by using a constant interval between samples taken
• random samples

  chosen by chance rather than according to a plan - all outcomes are equally chosen
• samples are taken from different positions in a habitat and those positions are chosen randomly