Limits of Plague, 2019-2023
Plague is still widespread, but the rules for where plague can exist in the wild are unknown. For non-ecologists, it is tempting to assume that certain rodent species are associated with plague reservoirs, but that intuition breaks down rapidly when you start comparing rodent species maps with plague reservoir maps.
There are plenty of examples: marmots are important plague reservoirs in Central Asia, but not in the Alpes; black rats are a reservoir of plague in the highlands of Madagascar, but virtually nowhere else.
Which rodents populations can be long-term plague reservoirs that can harbor plague for decades has long puzzled observers. To answer that question is the primary objective of "Limits of Plague". We will approach this problem by building ecological niche models (ENMs) that avoid the limitations of other attempts (which were focused on a regional scope only, using limited datasets, and generic rather than plague-specific input variables). With a vast amount of data now available from surveillance programmes from the former USSR, the USA, Brazil and China, and from historical records, the main challenge for us lies in using the right methodology to build and project ENMs as far across the globe as is reliably possible, and to test and select the right plague-relevant input variables for the models (e.g.climate instability, soil properties).
Our first paper, piloting a next-generation Ecological Niche Model is out now1
Carlson, C.J., Bevins, S.N. and Schmid, B.V. (2022) ‘Plague risk in the western United States over seven decades of environmental change’, Global change biology, 28(3), pp. 753–769.