Insights on the indicator capacity of <i>Artemisia</i> pollen in pre-Holocene paleoecology

In pre-Holocene paleoecology, Artemisia (Asteraceae) pollen is commonly considered an indicator of arid steppic environments in temperate regions. However, the >520 known species of this genus occur across a wide range of bioclimatic conditions. This paper comments on a recent comprehensive study that examined the identification of Artemisia pollen at the species level in relation to the bioclimatic conditions in which these species occur globally. Using scanning electron microscopy (SEM), three main pollen groups were identified, of which only one was indicative of arid temperate grasslands and deserts, while the other two corresponded to species from wetter biomes and generalist species, respectively. The authors of that study concluded that there is no correlation between Artemisia pollen morphology and bioclimatic characteristics. Therefore, Artemisia pollen cannot be used as an indicator of any specific vegetation type or bioclimatic domain. The significant intrageneric pollen homogeneity within Artemisia, along with the need for SEM to distinguish the few defined pollen types, severely limits its indicator capacity in routine light microscopic paleoecological studies. As a result, Artemisia pollen records still require additional paleoecological interpretation methods, such as assemblage analysis and modern-analog approaches, though none can replace paleoenvironmental reconstructions based on pollen-independent proxies.