A novel approach based on information theory to rank conservation strategies: an application to Amphibian metapopulations

Habitat fragmentation, reduction and degradation as well as the quality of habitat
connecting environments are critical for species persistence. Spatially explicit
metapopulation models considering environmental effects are natural candidates
for modelling population viability. However, metapopulations share the inherent
uncertainties of the population concept with vague field population definitions. The
recognition of the fuzzy nature of populations leads to operational definitions for
management purposes. To deal with scarce information and uncertainties in
predictions of intervention effects, Adaptive Management is useful. Accordingly,
the synthesis of monitoring information is performed with models whose features
are continuously adapted to the level of available information. To derive useful
indices for conservation strategy evaluation, we propose a novel approach based on
the Kullback–Leibler information measure. This is used to evaluate strategies aimed
at the conservation of amphibians in an alpine Rhine valley region (Canton of the
Grisons, Switzerland) and it is applied to outputs from an incidence function model
for Bufo bufo and Rana temporaria. For these species, establishing four additional
breeding sites along the Rhine river is a better strategy than placing two additional
sites in intensively cultivated land. Artificial ponds in residential areas contribute to
species conservation, and transfer of individuals to new sites has advantages over
reliance on spontaneous colonization. Bufo bufo and R. temporaria reacted similarly
to conservation measures, possibly due to their quite similar ecologies.