Using models to assess viability of orangutan populations and guide conservation planning

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Using models to assess viability of orangutan
populations and guide conservation planning

• Bob Lacy
• Chicago Zoological Society
• IUCN Conservation Breeding Specialist Group

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Multiple conservation workshops

• 1993 Population Habitat Viability Assessment
• 2001 Reintroduction Protection Workshop
• 2002 Conservation Reintroduction Workshop
• 2003 Preliminary Population Viability Analysis
• 2004 Population Habitat Viability Assessment
• 2005 Sumatran Orangutan Conservation Action Plan

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Population Habitat Viability Assessment

• Data
• People
• Tools
• Focused energy
• Bring attention
• conservation action

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Organizations involved

• IUCN Conservation Breeding Specialist Group
  (CBSG)
• IUCN Primate Specialist Group
• Orangutan Foundation
• Kinabatangan OrangUtan Conservation Project
  (Hutan)
• Sumatran Orangutan Conservation Programme
• Borneo Orangutan Survival Foundation
• Sabah Wildlife Department
• Conservation International
• The Nature Conservancy
• WWF-Malaysia
• TRAFFIC
• USAID
• Multiple universities
• and others

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Population Viability Analysis

• Synthesis of knowledge about
• a species,
• its environment,
• and human actions
• in a model of population dynamics

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Population Viability Analysis (PVA) models

• Use simulation models of population dynamics to
• simulate (mimic) life history, external factors,
  trends, management actions
• project possible future
• trajectories
• test proposed conservation
• actions

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Population Viability Analysis (PVA) models

• Use simulation models to
• gather as much information as possible
• help people to deal with uncertainty
• guide people to think more broadly about
  possible threats and possible actions
• provide a non-judgmental forum for testing ideas
  (computer model as the perfect reflective
  listener)
• make conservation planning a predictive science
• provide a framework for incorporating new data
• provide a way to present information to policy
  makers

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The Future is Uncertain

• Any of these trajectories might represent the
  future of the population. The distribution of
  outcomes reflects our prediction about it.

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Effect of Logging on Orangutan Population
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Fragmentation Due to Roads

• Existing NW Aceh, East Leuser
• Proposed East Middle Aceh, West Middle Aceh,
  West Leuser
• Fragmentation effects overshadowed by logging
  effects need to consider increased risk of
  logging

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Current Population Projection
50 decline in 10-12 years
Reduced to 1000 OU in 25 years
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So, what have we learned about orangutan
populations from models?

• We know a lot about orangutan population biology
• long-term field studies at Ketambe, Suaq,
  Tanjung Puting, and elsewhere allow us to build
  respectable models of population dynamics
• age of breeding, inter-birth intervals, birth
  sex ratio, mortality estimates

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Density-dependent effect on inter-birth interval
( breeding each year)
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So, what have we learned about orangutan
populations from models?

• We know a lot about orangutan population biology
• Orangutan populations can grow, at best, only
  about 1 to 2 per year
• Thus, they can withstand a loss due to poaching
  or other harvest of no more than 1 / year

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Effects of 0, 1, 2, or 3 removals / yr
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So, what have we learned about orangutan
populations from models?

• We know a lot about orangutan population biology
• Orangutan populations can grow, at best, only
  about 1 to 2 per year
• Populations smaller than about 250 are unstable
  demographically and genetically

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Populations of 1000
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Populations of 250
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Populations of 50
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So, what have we learned about orangutan
populations from models?

• We know a lot about orangutan population biology
• Orangutan populations can grow, at best, only
  about 1 to 2 per year
• Populations smaller than about 250 are unstable
  demographically and genetically
• Loss of habitat leads to loss of populations
  (duh!)

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Projections for Leuser populations
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Population Habitat Viability Assessment

• Data
• People
• Tools
• Focused energy
• Bring attention
• conservation action

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Working Groups

• Sumatra population assessment
• Borneo population assessment
• sub-groups for Sabah, W Kalimantan Sarawak, C
  Kalimantan, E Kalimantan
• Conservation Strategies
• Site Prioritization

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Site Prioritization

• Make substantial contributions to species
  survival
• Loss would jeopardize the taxon as an
  evolutionary unit
• Any threats must be addressed immediately

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Site Prioritization Criteria

• Habitat and population size of interconnected
  or potentially connected unit
• Biological considerations
• Save the largest units for each
• Taxonomic position
• Unusual habitat
• Peripherality
• Political unit

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Conservation Strategies

• Why have the old strategies failed?
• What new strategies might work better?
• What organizational structures are needed?
• What commitments and resources are needed?

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Conservation Strategies

• Create an Orangutan Scientific Commission
  (international)
• monitor status of populations
• raise awareness
• prioritize research and funding needs
• disseminate information
• assist with international fund-raising

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Conservation Strategies

• Create an Orangutan Conservation Forum (national
  level)
• communicate PHVA results with all stakeholders
• liaison between international OSC and local
  stakeholders
• advise on preparation of GrASP National Great
  Ape Survival Plans

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Thanks!