Area calculations

Calculating biodiversity crediting area from observations of indicator species

The full credited area for a BCP is dependent on the overlapping home ranges of the observed qualifying indicator species that lie within the crediting area — as determined by the union of individual observations within the same time frame.

Species are complex, dynamic, and diverse. Animals are typically observed at one geocode but have a far larger asymmetric habitat. For the purposes of simplification:

• Each indicator species' publicly-accepted home range area is normalized to a circle around the central observation point where the species was verifiably observed. For details on this choice, see the FAQ. See an example list of home ranges in Appendix E.

• Identification of individuals of a species is NOT required by the ISBM. While it may be relatively easy to accomplish for an indicator species such as a jaguar (based on markings, or more invasively with an implanted radio chip), it becomes prohibitively difficult when taking into account the wide array of species that may qualify for indicator species within an ecosystem. Further, many identification and population calculation techniques are invasive, and/or technically exclusive to IP and LCs.

• Observations are unioned. Because individual observations could be one, or many, individuals of an indicator species — if the same area contains more than one observation within a 60-day period the area is NOT double-credited, it is equated through a union of the home-range areas (see Time calculations). Thus the ISBM methodology remains conservation-only, as population growth may be difficult to prove—although it is acknowledged that more sophisticated methodologies may emerge to define and credit these areas.

A sample list of indicator species for Putumayo, Colombia with home ranges is provided in Appendix E.

Figure 8. Union of multiple jaguar observations to calculate crediting area from home range

Please note that species observations involve one data layer. For BCPs with project areas such as multiple adjoining land plots, grouped projects, or different segments, this layer might be split for calculations by another data layer.

Figure 8a. Division of a crediting area by a grouped-project boundary