Taxonomic uncertainty and the challenge of estimating global species richness

Biases in parasite biodiversity research: why some helminth species attract more research than others

“…The focus of parasite biodiversity research on either achieving a full inventory of extant species or just estimating how many there are on Earth is commendable, but logistically challenging ( Poulin, 2014 ; Carlson et al, 2020a ) and perhaps even unattainable ( Stropp et al, 2022 ). In contrast, obtaining further information on the species we already know can shed light on multiple aspects of parasite biology, from their evolutionary history to their ecological impacts.…”

Macroecological links between the Linnean, Wallacean, and Darwinian shortfalls

“…The LTG is characterized by a geographic trend in the quality of the information used for species delimitation. This uneven distribution of taxonomic knowledge can hamper estimates of global species richness (Stropp et al 2022), affecting our ability to compare biodiversity data from different regions of the globe, from different biomes, or even data from different areas within a single biome. The methodological approaches and conceptual frameworks used to delimit species are beyond the scope of this article.…”

“…Conversely, the tropical regions house a larger number of species and clades that generally require substantial research efforts (Cayuela et al 2011, Freestone andInouye 2014). Tropical taxa are thus more prone to future taxonomic changes through splitting or lumping of species (Freeman and Pennell 2021;Stropp et al 2022). This LTG is partially driven by differences in biological complexity in different parts of the world.…”

“…The uneven taxonomic uncertainty leads to unmeasured errors in diversification rates that can have a cascading impact on our understanding of how diversification rates relate to other aspects of biodiversity (e.g., species richness). To decrease these biases in diversification rates, it is important to consider the history of taxonomic progress for the taxa involved (Stropp et al 2022) by evaluating the variation of valid species through time (Alroy 2002;Williams 2022). The probability of splitting or lumping a valid species in the future can be estimated by simulations (see below) that would allow the total number of species predicted under multiple simulations to match the overall number of species predicted by species accumulation curves (Diniz-Filho et al 2005;Lobo and Martín-Piera 2002;Lobo et al 2007) or the application of SAR/ SAD (species-area relationships/species abundance distributions) analyses (ter Steege et al 2020).…”

On the end of evolution – Humankind and the annihilation of species

“…Thus, it is one of the paradoxes of our time that although we have, for example, reached outer space and explored the moon, we actually live on a planet that remains largely unknown to us in biological terms, for the majority of the Earth's animal and plant species are, for several reasons (e.g. May, 1994; Stropp et al, 2022; Struck et al, 2018), still undiscovered and unknown, scientifically neither named nor described. This is hardly true for conspicuous vertebrates such as birds or mammals, but all the more so for the plethora of rather inconspicuous invertebrates, for example, arthropods such as insects, spiders and crabs, but also molluscs such as snails and mussels.…”