1/21 MWC

White Abalone: At Risk

• Haliotis sorenseni

• Allee Effect

• Mobility

• After they were listed on the endangered species act, they still haven’t recovered

• Male and females have to be within 10 yards of each other for broadcast spawning to work

• Ideal: 1 m apart

• Efforts to restore population with info in mind

• Challenges: some areas see many abalones, so they eat a lot, while other areas don’t see them so don’t catch them; abalones are clustered in one area which makes it look like there’s a lot when they have a small range

Marine Species: Extinction-Proof Traits

• Immense ranges

• Huge populations

• Millions of eggs

But these traits don’t result in viable individuals at all times.

Risk Factors

• Late maturity

  • sea turtles, sharks

• Low reproductive rate

  • marine mammals

• Adaptation to environment with little disturbance

  • sea birds

• Passive dispersal

  • invertebrates, fish

• Bycatch/indiscriminate fishing

  • catching fish that aren’t your target species, not discriminating

Cumulative Effects

• Exposure to multiple factors exacerbates vulnerability

• Extinction vortex (sums up how a species becomes extinct)

  • Frankham et al

  • environmental variation + demographic stochasticity + catastrophes = reduced Population (N)

  • habitat loss, pollution, over-exploitation, exotic species = small, fragmented, isolated populations

  • Inbreeding, loss of diversity

  • Reduced adaptability, survival, and reproduction

    

Conservation Challenge: How to Prioritize?

• Extinction risk is one of many factors to consider when establishing conservation priorities

• Distributional factors, biological factors, societal values, logistical factors, economic factors, other factors also contribute

Conservation challenge: lack of knowledge

• We don’t know what we don’t know

• What is out there?

• Natural history

• Taxonomy (wide-ranging species)

• local adaptations

  • opportunistic species

    
    

Conservation Challenge: shifting baslines

• The incremental lowering of standards, with respect to nature, in which each new generation:

  • lacks knowledge of how the environment used to be

  • redefines what is ‘ natural’ according to personal experiences

  • sets the stage for the next generation’s shifting baseline

• Difficult to quantify declines because data have been collected for only the last 20-50 years

• these data are used as our ‘historic maxima’

• heavy consumption has been underway much longer

Summary

• A variety of life history and ecological traits of marine species result in extinction risk and therefore present numerous conservation challenges

• When the rate of environmental change out-paces behavioral flexibility, changes in community composition and population dynamics become evident

• Understanding of ‘baseline’ behaviors and habitat requirements of species and ecological patterns and processes is therefore useful for conservation to be successful