*2.4. Protecting Species*

### 2.4.1. Forensics and Monitoring Traffic in Endangered Plants

It is abundantly clear to all biologists that biodiversity is under severe threat across the globe due to natural resource overutilization and exploitation, major habitat degradation, and climate change caused by humans. Biodiversity conservation is imperative. DNA barcoding, as a tool primarily for species identification, can be used in three general ways to further biodiversity conservation: (1) to accurately monitor and thereby protect endangered species subject to illegal commercial trade (i.e., point-of-origin tracing [148,149]), (2) to track biological invasions, and (3) to provide data that will assist in the estimation of phylogenetic diversity for setting conservation priorities [150].

Although DNA barcode-based discrimination at the species-level is not possible in all groups of organisms, DNA barcodes have been utilized for forensic identification of algae [151], plants [152,153], invertebrates [154], and vertebrates [155]. A significant driving force in developing DNA barcode technology for plants has been the need for an accurate and inexpensive tool for the identification of illegal timber products, especially those listed in the Convention on International Trade of Endangered Species (CITES). For example, in tests of the commercially important mahogany family (Meliaceae), most of the standard DNA barcode markers fell short of expectations for discriminating species, although the nuclear ribosomal internal transcribed spacer (ITS) was able to identify some species in this family [156]. A higher level of discrimination using standard markers was demonstrated among commercially important and threatened species of trees collected at timber processing plants in the tropical dry forests of India [157]. This same success was demonstrated in timber species found in *Araucaria* rain forests of the southern Atlantic coast of Brazil [158], which contains many threatened species of trees, especially in the family Lauraceae. In Madagascar, a recognized biodiversity hotspot, Hassold et al. [159] used DNA barcodes in an effort to monitor illegal timber trade, especially in species of rosewood (*Dalbergia* in the Fabaceae). They demonstrated the limitations of the standard genetic markers in identifying closely related species of this genus, although some success was achieved. In addition to timber trees, DNA barcode libraries have been developed for other taxonomic groups of threatened and endangered plant taxa listed in CITES, e.g., orchids [160]. Currently no more effective tool than DNA barcoding exists for accurate identification of products sold in public markets [161–163] or as illegally harvested species intended for trade intercepted at ports [164,165]. As global DNA barcode reference libraries grow, so too does the capacity to enforce conservation laws and to monitor illegal trade in endangered plants.

Traditional medicines, teas, and herbal supplements are another important component of the commercial need for accurate plant species identifications by regulators and quality control specialists. It is estimated that medicinal plants account for billions of US dollars in annual revenues in the United States alone [166]. From the initial use of plant DNA barcodes, applications to monitor this market have been in development [167]. However, many of these trials to use DNA barcodes to identify commercial medicines and herbal supplements have shown limited success in discriminating among species. Some of the major obstacles have been the lack of comprehensive DNA barcode libraries required to make accurate comparisons among species of herbal teas and supplements, and the

absence of standardized taxonomy and common names listed in the herbal catalogs and pharmacopeias (e.g., Stoeckle et al. [168]; de Boer et al. [169]). Building the required DNA barcode libraries (see below) and unifying the taxonomy in the literature on traditional medicines are challenges for the future.
