Taxonomic anarchy or an inconvenient truth for conservation? Accelerated species discovery reveals evolutionary patterns and heightened extinction threat in Afro-Malagasy small mammals

Abstract

We respond to recent criticisms of supposed “taxonomic anarchy” which is said to hamper conservation efforts. Using examples from African small mammals, we document recent increases of 13% (rodents) and 18% (bats) over the past three decades in the number of recognized species of Afro-Malagasy rodents and bats. By reference to a number of case studies involving Afro-Malagasy taxa (predominantly from montane habitats), and a suggested four-criterion approach to delimiting species accurately, we show that these increases are a genuine reflection of speciation in cryptic species complexes. Moreover, we show that some of these cryptic species are subject to increased extinction risks due to small population size and anthropogenic changes (habitat degradation and climate change). These changes were captured accurately in a recent Mammal Red List of South Africa, Lesotho and Swaziland, indicating that taxonomists and conservationists can work together to assess the Red List status of cryptic species based on robust taxonomic revisions.

Mammalian species and the twofold nature of taxonomy: a comment on Taylor et al. 2019

“…These arguments generally miss the key points in our various publications (Garnett and Christidis 2018a,b). The most recent case is the paper by Taylor et al (2019) published in this journal. Our views are variously portrayed as a "condemnation of perceived 'taxonomic inflation'", as having received "undue attention" and as defending the Biological Species Concept (BSC).…”

“…None of us deny that taxonomy is a scientific discipline that generates and tests hypotheses about the natural world nor wish to constrain that science in any way. Indeed, it is a research field in which we are closely involved: Taylor et al (2019) cite the research led by one of us (Christidis et al 2014) as an example of "very high standards of taxonomic description and publication". Nor do our views depend on any particular species concept, although, like Taylor et al (2019), Zachos (2016Zachos ( , 2018a embraced and defended the ontological superiority of the ESC.…”

“…Species taxa are little twigs in the Tree of Life: portions of biodiversity that exist independently of our efforts to systematise nature. They are real entities that can be discovered as a result of the high-quality taxonomic research reviewed by Taylor et al (2019). The Tree of Life, however, is an encaptic system displaying a nested hierarchy with a fractal pattern (lineages within lineages).…”

“…This of course would be complicated but would remove the partly arbitrary step of ranking. Taylor et al (2019) actually present very relevant data on how insights into biodiversity and its distribution contribute to conservation, but none of what they say necessarily hinges on taxonomic names. It only does so because we have chosen to give different levels of value to the different ranks (interestingly, not a view necessarily shared by the wider public, Garnett et al 2018).…”

“…If we continue to do so, then streamlining and standardising our ranking decisions becomes a necessary aspiration. The principles underlying the "Consilient Solution" advocated by Taylor et al (2019) is a welcome attempt at this kind of standardisation. The problem of incommensurability does not go away, however, and this was exactly what the contentious suggestion by was about.…”