The role of taxonomy in conserving biodiversity

As currently understood, the genus Octodon contains five species degus, lunatus, bridgesii, pacificus, and ricardojeda. Previous phylogenetic studies suggest that genus specific diversity is underestimated. In order to evaluate the taxonomic diversity of Octodon, we implemented unilocus (cytochrome-b) and multilocus (cytochrome-b + 4 nuclear genes) species delimitation methods. Octodon degus was recovered as a sister of the other species of the genus. The unilocus bGMYC and mPTP methods, based on cytochrome-b sequences, delimits 11 and 7 candidate species respectively, and both methods fail to recognize O. pacificus from O. ricardojeda. Results of the multilocus analysis (BPP) vary as a function of the dataset used. When the five genes are used 11 species are delimited, while eight species are delimited when only the nuclear genes are used. Octodon bridgesii is shown as comprising at least two species (one on the Pacific coast and the typical form found on the Andean slopes), while O. ricardojeda may comprise two species (one on the Chilean side of the Andes and the other in Argentina). Likewise, both multilocus matrices recover O. pacificus as a distinct species. This shows that species diversity of Octodon is underestimated. Remarkably, many of the delimited species based on genetic data are morphologically differentiated in cranio-dental characteristics. However, a pair of species has not achieved morphological differentiation, being cryptic species. Finally, the incongruence between mitochondrial and nuclear phylogenies suggests that processes such as incomplete lineage sorting and/or introgression have been present during the radiation of the genus.

Comprehensive biodiversity inventories are expensive and time-consuming to achieve, especially for groups of megadiverse organisms. One approach to resolve such situations is to utilize biological substitutes, referred to as surrogates. A surrogate should provide meaningful information at a lower cost and/or effort than the original level of resolution. Studies have shown that species richness is often not the best or most appropriate component or predictor of biodiversity. Functional diversity can be used as a measurement of the ecological differentiation between habitats or between biological functions. We evaluated the use of several taxonomic metrics as potential surrogates for leaf-litter ant assemblages distributed in 65 Atlantic rainforest sites. Our goal was to find reliable and economic substitutes for both taxonomic and functional leaf-litter ant diversity and composition. We tested four potential surrogate approaches for taxonomic metrics and three for functional group metrics. Additionally, we also evaluated the time and costs involved. We used a large leaf-litter ant database that comprises 364 ant species, respectively classified into 13 or 26 ant functional groups based on either a general and specific resolution. Subfamily was found to be an unacceptable surrogate for both taxonomic and functional group metrics. Mixed-level and indicator taxa metrics were rated as ‘excellent’ taxonomic surrogates. Mixed-level and genus metrics were rated as ‘excellent’ or ‘acceptable’ functional group surrogates when considering the most general functional resolution, while mixed-level and genus were considered as ‘excellent’ surrogates when considering the more specific resolution. The monetary and time costs to identify ants to genus level were lower than those using indicator taxa and mixed-level metrics. The use of a certain higher taxon functional and taxonomic surrogates allows a reduction of survey and analysis costs while still enabling the analysis of biological diversity from the taxonomic and functional point of view.

Conservation biology and biodiversity are today disciplines that no serious biologist can ignore, yet the practical importance and scientific value of taxonomy is greatly overlooked in today conservation practice. This is particularly true for researchers that have spent most of their time investigating the biology and management of a few species of mammals in a few places. It is here highlighted that the trend to replace taxonomic infraspecific units by ad hoc ecological and ‘conservational’ units having no universality is based on a misunderstanding of the concept of taxon as being a fixist and essentialist one. In this perspective paper, based on the author’s experience, several case-studies are discussed showing how a misunderstanding of taxonomy hampers biodiversity cataloguing and, by consequence, conservation of evolutionary history.

The genus Alveopora is a scleractinian coral taxon whose phylogenetic classification has recently changed from the family Poritidae to Acroporidae. This change, which was made based on single-locus genetic data, has led to uncertainty about the placement of Alveopora and the ability for deep evolutionary relationships in these groups to be accurately recovered and represented by limited genetic datasets. We sought to characterize the higher-level position of Alveopora using newly available transcriptome data to confirm its placement within Acroporidae and resolve its closest ancestor. Here we present an analysis of a new 2031 gene dataset that confirms the placement of Alveopora within Acroporidae corroborating other single-locus (COI, 16S and ITS) analyses and a mitogenome dataset. We also resolve the position of Alveopora as sister to the genus Montipora. This has allowed the re-interpretation of morphology, and a rediagnosis of the family Acroporidae and the genus Alveopora.

Clinal variation and cryptic species complexes are challenges to taxa targeted conservation. These issues are particularly problematic for the estimation of species geographic distributions, generally resulting in erroneous estimations due to unrecognized species. However, integrative taxonomy could help to solve these problems, revealing geographic and genealogical limits of species when they are not clear through morphological comparisons solely. Here we evaluated the efficiency of integrative taxonomy in identifying a new population of leaf frog from a species complex. This example was chosen because correct species identification can have an impact in the conservation assessment of a threatened species. The new population belongs to Pithecopus centralis, extending its distribution by approximately 400 km to the east of its known distribution. This identification was confirmed by the consensus between genetic, morphometric and bioacoustic evidence, even with some level of uncertainty when using each piece of evidence. We reassessed the conservation status of the species following recommendations from the International Union for Conservation of Nature (IUCN), after having checked and cleaned the data used for the species categorization in the Brazilian Red List of Threatened Fauna. In spite of the distribution extension reported here, our results demonstrate that the status of the species should be revised in the national Red List, reinforcing the importance of a rigorous taxonomic approach to improve Red Lists assessments.

Red Lists are legal instruments that guide decisions within the context of conservation. Such lists can indicate the most appropriate conservation actions, leading to choices of priority areas for conservation, or create alternatives to ensure the preservation of threatened species. However, if Red Lists are effective tools in the conservation of threatened species, then it is important that we have guaranteed the quality of taxonomic delimitation of these taxa. Here we discuss a case of taxonomic confusion, emphasizing the implications of misidentification in Red Lists. To avoid mistakes in species conservation, we advocate that a minimum level of taxonomic knowledge is needed to ensure success in preserving target species. Therefore, complementarity of taxonomy and conservation guarantee stronger conservation actions.