SUSTAINABILITY INDICATORS Chapter 2 Sustainability Indicators in Practice
SUSTAINABILITY INDICATORS Chapter 2: Sustainability Indicators in Practice Tamara Belyakhina Imtiaz Ahmed
Agenda − Maximum Sustainable Yield (MSY): ● Introduction ● Carrying Capacity ● Animal population models ● Problems with MSY application ● Collapse of Peruvian anchovy fishery − AMOEBA
Introduction to MSY − MSY: Maximum Sustainable Yield • Number or biomass of individuals that can be removed from an ecosystem without driving the population down • Major idea was introduced in 1930 s • Important consideration of exploiting a resource for gain • State SI for the ‘Protection of the Oceans, all Kinds of Seas and Coastal Areas’
Carrying Capacity − The maximum number of individuals of a species that an ecosystem can sustain. − If the carrying capacity is exceeded, the population will be limited through lack of resources. − How many animals can be taken without destroying the stock? => Models of species population
Animal population models N - population size r - indicator of the multiplication rate of each individual in the population K - carrying capacity
Problems with MSY application − Doesn’t fully take account of the complex nature of the ecosystem: • competition, symbiotic or commensal relationships with other species • tropic relationships • changes in carrying capacity due to pollution or other human influences − Highly dependent on the choice of starting point − r and K are assumed to be constant, and are difficult to estimate in practice − Doesn’t take into account difference between individuals in population in size, age, etc.
The collapse of the Peruvian anchovy fishery − The collapse of the Peruvian anchovy fishery in 1972: • the largest fishery till 1971 • fishing at or below MSY • heavy fishing in 1960 -1970 => excessive removal of fish at reproductive age • warm water phase in 1972 => negative effect on the anchovy population
Sustainability indicators in marine ecosystems: The AMOEBA approach − AMOEBA is an acronym which in Dutch stands for ‘general method for ecosystem description and assessment’. − Highly visual approach to encapsulating sustainability − It has been created with non-specialists in mind − Ten Brink et al (1991) took a broad view of sustainability and concluded that there were three categories of ‘valuable characteristics, whose sustainability is desirable’: • Yeild • Bio-diversity • Self-regulation
Advantages of AMOEBA Approach − Its appeal of measuring sustainability is not difficult to understand − Sustainability is summarized in visual terms as AMOEBA with a clear, even if subjective, sense of a target − It has a very practical feel, primarily because it was designed to be used as a decision-making tool in environmental management
Criticism on AMOEBA Approach − The AMOEBA is fundamentally based on numbers (population sizes), it does not in itself provide any information on the mechanisms involved in the changes (the pressures) − The approach is based on simple addition (all indicators are combined into one diagram) − The third problem with the AMOEBA approach is centered on the choice of a reference condition
Conclusion − This chapter has examined two levels of SI: an individual SI (MSY) and an attempt at collecting individual indicators together as a single diagram (AMOEBA). − the main problem with such SIs is that they attempt to encapsulate a very complex system in a few simple measures
Thank you for your attention!
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