 The second part of Santana’s argument is this pluralism is unproblematic only if there is some true surrogate that covaries with the other surrogates and hence biological value (Santana 2014: 768–73). However, he complains that the available evidence suggests this is false. If we augment species richness with abundance we will not capture certain biological values since, for example, the rarity of a bird species increases its value and does not reduce it. Phenotypic variation requires the sort of morphospaces discussed above, but these as we saw are local and cannot be compared across very different taxa. Hence, even if we augment species richness with phenotypic variation we are unable to determine the biodiversity present in comparable ways. Likewise, evolutionary diversity of the sort that Faith described does not necessarily correlate with species richness. In one study of the South Africa’s cape region, it was determined that the eastern region of the cape had greater evolutionary diversity as measured by the number of speciation events between clades whilst the western region of the cape had greater species richness (Mooers 2007). Speciation events are often unrecoverable from the fossil record and so this sort of diversity cannot typically augment species richness. Lastly, as we noted above, the connection between species richness and ecological properties like stability is extremely complicated and controversial. It has not been show in a robust manner that greater species richness leads to greater ecosystem or food web stability.