VCE Environmental Science

Coastal wetlands at Port Fairy – OBP habitat (picture by Tracey Grey)

Population Viability Analysis is a process to identify the threats to a species and the likelihood that it will survive into the future. PVA aims to protect a threatened species in the short term and then to establish a population that will be maintained naturally, without intensive management in the longer term. The process includes:

1. Planning research and data collection

2. Assessing vulnerability.

3. Ranking management options.

More information about Population Viability Analysis from Wikipedia and other sources.

Environmental Risk Assessment deals with the probability of an event causing a potentially undesirable effect. Quantitative risk assessment thus deals with statistics, because probability is the mathematical measure of risk, and with hazard assessment which determines the nature of the undesirable effect.

The Precautionary Principle states that where irreversible damage may be caused due to an action, policy or  development, then the onus is upon the decision-makers to prove that there will be no undue impact on the environment. When there is a lack of scientific data upon which a decison can be made, then no action should be taken that may impact upon the environment.

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We have discussed the three levels of biodiversity (genetic, species and ecosystem) and reasons for protecting biodiversity and some of the threats. Next we will discuss how populations are measured, the categories of conservation and strategies we use to reduce the threats to biodiversity. The IUCN redlist (International Union for Conservation of Nature list of all known species and their conservation categories) defines critically endangered, endangered and threatened species according to their population size, distribution and likelihood of extinction.

This worksheet (conservation-case-studies) asks you to classify eight different species according to known data. Try to classify the local threatened species listed in the post below using the IUCN criteria. One of the commonly used methods for measuring the number of individuals in a population is “mark and recapture” or “tag and release”. We will do an experiment to simulate this process here (mark-and-recapture-expt).