Abstract:
If transparent and inclusive stakeholder discussion delivers a consensus for active
rewilding, then five steps are recommended for operationalizing that decision,
focused initially on the large herbivore assemblage. Consideration of large
predators could follow, contingent upon the establishment of prey populations.
First, determine the potential biomass density (kg/km2) of large mammalian
herbivores in the target landscape. Regression models based on rainfall or
primary productivity are helpful if applicable, otherwise comparative studies are
needed. Second, use empirical data from reference ecosystems to apportion
biomass density among functional types, crudely defined by body size and
feeding type (grazer, browser, mixed feeder). Third, identify specific functional
traits (coarse grazing, endozoochory, etc.) of particular local importance. Fourth,
identify species within each functional type that are already present, estimate
their potential biomass densities, and thus identify the shortfall within each cell
of the body size x feeding type matrix. A candidate set of native and non-native
(surrogate) species is then identified to make up the shortfalls. This is followed
by an iterative process of estimating equilibrium population sizes, stakeholder
acceptance, and viability of each potential population. Fifth, stakeholders must
be inclusively re-engaged to visualize the potential assemblage, its expected
functional interactions, the ecosystem services to be delivered, and the long-term
costs (including opportunity costs) and benefits. When a plan is supported, local
stakeholders should be integrated as active participants in the implementation,
monitoring, and championing of their rewilding project.
