Ecosystem Function In Biodiversity Offsets

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Ecosystem Function In Biodiversity Offsets

• What
• Why
• hoW
• By Wayne White

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What is it?

• Ecological processes, including disturbance
  regimes and flows of nutrients, energy and water
• Harder to measure, but essential for replicating
  role of ecosystem in landscape context

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Why Important?

• Either
• To ensure viability of rare species or habitats.
• To ensure maintenance of ecosystem services
  provisioning, regulating, supporting.

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Examples

• Example 1 Disturbance Regimes
• All ecosystems rely on natural disturbance
  regimes, such as periodic fire. An offset
  should take into account the role of the impacted
  and the offset sites in landscape-level
  disturbance regimes. The disturbance regime may
  have much to do with contiguous areas or size.

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• Example 2 Hydrology
• The impacted site may play an important
  hydrological role within the watershed, such as
  maintaining water quality and ameliorating
  flooding. An offset should replicate, or
  compensate in other ways, for impacting this
  function. This may be particularly important to
  downstream human and aquatic communities.

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How do You Measure?

• Protocol might include
• Identify key drivers or disturbance regimes and
  minimum area for offset site to maintain it
• Identify watershed function and probability of
  impact
• Identify minimum habitat requirements for species
  of concern
• Identify stakeholders potentially affected by
  impacts to ecosystem function

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Measure What?

• Things to consider
• Surrogate or indicator species
• Ecosystem services (e.g., water quality)
• Hydrology

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Some last thoughts on function

• Sustainability
• Geographic location of offset will determine
  ecosystem function, especially hydrology
• Offset may need minimum scale to replicate
  disturbance regimes, nutrient, energy and water
  cycling
• Depends on condition of habitat adjacent to
  offset
• May relate to conservation biology principles-
  minimum dynamic area and MVP