Dung fungi as a proxy for megaherbivores: opportunities and limitations for archaeological applications

The use of spores of coprophilous fungi from sedimentary sequences as proxy evidence for large herbivore abundance has garnered pronounced attention and scrutiny over the past three decades. In response to the rapid rate at which new information is being discovered on this topic, this paper presents a brief review of the archaeological applications so far, and outlines opportunities and limitations of using Sporormiella as a proxy for herbivore abundance. Specific archaeological uses of this proxy include understanding megaherbivore extinctions and human land use patterns such as pastoralism and agriculture. We analyse how dung fungal records are formed and review the mycological literature to outline factors affecting spore reproduction and preservation. These include how strongly each commonly used dung fungal taxon relies on dung as a substrate and environmental factors affecting dung fungal reproduction and coprophilous fungi deposition. Certain laboratory preparation techniques adversely affect spore representation on pollen slides. The methods of analysis and quantification of spore records also impact our understanding. We describe good practice to increase precision of analytical methods. Due to limitations imposed by some of these factors, it is possible that an absence of dung fungi from a palaeoecological record does not imply an absence of herbivores. However, consideration of these factors and inclusion of as wide a range of coprophilous spore records as possible increases the reliability of such inferences.