4.3 Setting Meaningful Targets
4.3.3 Expert advice and peer review
The choice of ecological targets used in an analysis could have far‐reaching implications, and will have to be defended, perhaps in a court of law. The initial selection of ecological targets by the analysis team should incorporate expert and sometimes also stakeholder input (see Chapter 10: Using Marxan in Multi‐Stakeholder Planning Processes). Box 4.1 shows the questionnaire that was used in a series of expert workshops to inform marine conservation planning processes in British Columbia (BC), Canada. Good practice is to aim for agreement on a range of plausible target values. However, many experts are not comfortable with the use of numerical target values, and/or tend to overvalue their own particular areas of research. Thus the task of balancing the numeric values for all ecological targets in the analysis may ultimately reside with the core analysis team.
During refinements, it can be very helpful to consider the relative target values of conservation features as a related set rather than absolute values for individual features.
In earlier BC analyses, protection targets for features were first ranked relatively using quantitative terms (low, mod‐low, moderate, mod‐high, high, very high) and then afterwards various numerical targets were applied to these terms in different scenarios (Ardron et al. 2000, Ardron 2003, 2008).
Box 4.2: Expert workshops to assist in setting targets
The British Columbia Marine Conservation Analysis (BCMCA, www.bcmca.ca) has taken an expert‐based approach to selecting features and setting targets. To do this, the project team organized one‐day themed expert workshops (for ecological themes including seabirds, marine plants, fishes, invertebrates, and marine mammals). After an introduction to the project, each workshop was dedicated to filling out worksheets based on the questions listed below.
SECTION 2 - ECOLOGICAL TARGETS
Measure Target (range)
Comments/
Justifications
The type of measure that will be used to capture the marine feature (e.g., Percent of current extent of feature in study area, percent of current population, number of occurrences).
The amount of the feature required for meeting the BCMCA's 4 ecological objectives: (1) Represent the diversity of BC's marine ecosystems (2) maintain viable populations of native species; (3) sustain ecological and evolutionary processes; (4) build a conservation network that is resilient to environmental change. Ranges should span minimum to preferred amounts.
SECTION 3 - ECOLOGICAL CONSIDERATIONS Minimum
Patch Size Replication Separation Distance
Other Ecological
Considerations Comments
Minimum size of patch/population needed to ensure population viability.
How many unique patches are needed to ensure long-term population
persistence/to safeguard against disturbances?
The minimum distance that distinct patches of a feature should be from one another (consider dispersal distances).
e.g., connectivity, ecosystem linkages, dynamics, special management considerations.
SECTION 4 - SOURCES OF FLORA DATA AND PRE-PROCESSING
Dataset/Layer Description Geometry Provider,
Custodian Extent
Key Fields/
Attributes
Spatially georeferenced data that captures the location of the features.
Preference will be given to digital data. This list need not be inclusive but should represent the best available data for science-driven analyses.
Brief
description of dataset.
Geometry type (point line or polygon)
Data provider/
reference
Geographi c Extent of Database
Descriptive information stored with the spatial data.
SECTION 5 - PRE-PROCESSING Pre-Processing
How should this dataset (or combined datasets) be processed/prepared for use in Marxan?
SECTION 1 - FEATURES
Marine Feature Rationale
List the unique species/ecological features from this dataset (e.g., species, families, groupings of species or of species habitats) that require individual consideration in the BCMCA. You may also wish to delineate features by season/ region or both.
Justification for classifying features or treating them separately.
Box 4.3: Lessons from the expert workshops By Karin Bodtker, BCMCA
The BCMCA found that completing worksheets (see Box 4.2) worked better in some workshops than others. In general, they had greater success completing the worksheet under these conditions:
• Features were relatively easy to itemize on a species–by‐species basis.
• The range of experts in attendance covered the full range of species groups being discussed.
• The experts in attendance either held the data they were recommending for the BCMCA project or they had good knowledge of them.
• There were no prior misconceptions about Marxan.
The BCMCA found that even though they had developed clear ecological objectives for Marxan scenarios, many experts were uncomfortable recommending target ranges for features because they usually had little or no evidence to support their recommendations. In hindsight, these three suggestions may help to solicit clearer responses from experts:
• Develop materials on examples of real‐world Marxan analyses. From these, discuss a range of scenario objectives, itemized features, targets and results.
• Acknowledge that peer reviewed science that prescribes targets based on specific objectives largely does not exist and in order to move forward the project is trying to ascertain reasonable target ranges based on expert knowledge of the relevant ecological features.
• Emphasize that a range of targets will be explored, acknowledging that a single
“right” number probably does not exist.
Furthermore, BCMCA held workshops at different times with different attendees and facilitators over a ten month period. While the format for the workshops was the same (large group plenary and small group break‐out sessions with 4‐6 experts in each small group), there were different approaches taken by different groups for identifying features or targets, possibly the result of “group‐think.”
Box 4.4: An alternative to expert workshops to assist in setting targets Dave Nicolson, Black Coffee Consulting
An alternative approach to workshops with worksheets would be to hold a workshop focused on identifying features and data sources to populate those features, and introducing the topic of targets, followed by a Delphi survey/questionnaire to help set targets for each of the features. Invited experts would independently assign targets for all identified features, then be shown the average target and range of targets from all experts and be given an opportunity to revise their responses. Benefits of this approach include:
• reduced group‐think bias;
• experts know the metrics that the data support prior to assigning targets;
• efficient use of participants time; and
• all experts have equal opportunity to contribute.
Difficulties of this approach include:
• low response rate when soliciting expert feedback by questionnaire;
• time lapse between explanation of targets and request for target recommendations (i.e., experts forget or are unsure and do not respond as a result); and
• Opinions on features and targets beyond participant expertise.