Posts Tagged ‘USA’

I’ll never use anything but New Mexico piñon in my candy!

Wednesday, December 15th, 2010

David D. Breshears, Laura López-Hoffman and Lisa J. Graumlich published an interesting paper in the journal AMBIO on adaptation to sudden ecosystem crashes that strongly affect the delivery of ecosystem services.

They argue that climate change might lead to increasingly frequent events of sudden, large and patchy ecosystem crashes were ecosystems undergo important changes in their structure and functioning. Because the particular timing, location and intensity of ecosystem crashes are generally unpredictable, and that ecosystems can rarely be made resistant to crashes (by definition), stakeholders will have to adapt to the consequences of ecosystem crashe if, when and where they occur.

The authors explore how a recent drought-induced tree die-off of piñon – juniper woodlands across the SW United States has altered the capacity of these woodlands to support human well-being. They relate scientific studies of drought impacts on the ecology of these woodlands and accounts in the media of how stakeholders are being impacted and are responding to these impacts.

The authors suggest that increasing stakeholder resilience to sudden losses of ecosystem services varies according to how strictly the particular ecosystem services are tied to particular location. They introduce the concept of “portability” to describe the degree to which an ecosystem service is tied to a particular location.

It is crucial to understand how dependency on certain types of ecosystem services may shape stakeholder flexibility in choice of location and in turn their adaptive capacity

As an example, piñon nuts are a portable service (with some limits) while the view from someone’s home is not – but this also depends on how flexible people are in terms of home location. Ecosystem service portability must be analyzed in conjunction with stakeholder or beneficiary’s mobility: i.e. how location-flexible rather than location-centric they are.

A famed Albuquerque candy makers says ‘‘I’ll never use anything but New Mexico piñon in my candy. I won’t go to the Chinese pine nut or the Nevada pine nut because it isn’t right. That would be like selling Native American jewelry that was made in Hong Kong”

The paper introduces two concepts – ecosystem service portability and stakeholder flexibility – that are interesting to consider in analyses of vulnerability to climate change in general, and of adaptation options to specific changes in ecosystem properties in particular. Stakeholder flexibility must of course be investigated in conjunction with ecosystem service substitutability: can a cactus replace your beloved piñon in your backyard?

Setting restoration targets : how specific should they be?

Tuesday, December 7th, 2010

In a recent paper published in the journal Wetlands, Diane De Steven and her colleagues present a 5 year restoration experiment where they tried to pilot restored coastal depressional wetlands in South Carolina to either herbaceous wetlands or wet forests. They failed!

Well, they didn’t fail overall. In fact, they generate a whole suite of restored wetlands that are well within the range of preserved wetlands in the region in terms of hydrology and plant communities. What they failed to do was to correctly predict which one of the 16 wetlands they restored would (likely) evolve into either a herbaceous wetland or a wet forest. This is because they could not predict the restored hydrology of each wetland (restored by plugging drains) which is the main determinant of tree establishment, ahead of planting tree seedlings into the wetlands targeted to become wet forests.

Diane De Steven and her colleagues draw several conclusions from this outcome :

  • There are high stakes in evaluating ecological restoration success in wetlands because of the requirements for mitigating wetland losses
  • Restoration success is rarely a simple yes / no outcome
  • Specifying, in advance, a specific plant community as a target for restoration ignores the variability of ecological (and community) dynamics and under-appreciates the multiple possible states of natural wetlands
  • More flexible restoration targets, based on a spectrum of reference communities (“natural” or otherwise) is more fitting to an adaptative management approach to restoration.
  • The spectrum could be defined in terms of wetland functioning, plant communities or even functional groups or functional traits (thereby recognizing that different plant assemblages can provide similar functions).
  • These are interesting ideas to keep in mind when discussing restoration (of course!) but also in designing assessment methods for wetland mitigation : with which metrics and against which targets should losses and gains in wetland condition be assessed?