Physical Surrogates for Biodiversity

Geoscience Australia is investigating the use of physical surrogates to map and predict Australia's benthic marine biodiversity.

A successful surrogate of benthic marine biodiversity will show a quantifiable, significant relationship with patterns of biodiversity or habitats at a given scale. There will also be a clearly associated process to explain the observed relationship. Metrics of surrogacy will indicate the degree of relationship (linear or non-linear) between the surrogate and biodiversity and the level of confidence in the result. The statistical approaches adopted for this analysis will be determined by the character of the data available, especially biological datasets that usually vary considerably in taxonomic resolution, format, sample scale and data density.

The influence of several potential physical surrogates such as latitude, depth, current speed, and substrate type on patterns of benthic marine biodiversity (e.g. distribution of biological communities) is clear and well documented in some specific benthic environments (e.g. Kostylev et al., 2003; Roff et al., 2003; Snelgrove and Butman 1994; Williams and Bax 2001; Post et al. 2006). However, for other variables (e.g. sediment sorting; acoustic reflectivity, energy exposure) and less-studied environments (e.g. continental slopes, canyons, seamounts, submerged reefs) the relationships are poorly known. Therefore, two key questions in surrogacy research are:

  1. Which physical variables are the best surrogates for patterns of biodiversity in the types of biogeographic and depth settings that are representative of major marine ecosystems? and
  2. Are there as yet untested physical parameters that represent useful surrogates?