An international team of scientists, which includes Spaniards, warns of the need to preserve these essential organisms for the ecosystem.

One of the many parasites described.

Parasites make up one of the most diverse and ecologically important groups of animals on Earth, but a third of its species is at risk of extinction over the next 50 years and research on them is relatively sparse.

Faced with this situation, an international team of scientists has just published a special volume in the journal Biological Conservation, a kind of “foundational launch” of the discipline “parasite conservation biology “, which brings together some of the most famous parasitologists in the world. The work includes various studies on its conservation and a main study detailing an ambitious plan of twelve goals to be developed over the next decade.

One of the participants in this special volume is Jorge Doña, a Marie Curie researcher from the Department of Zoology at the University of Granada (UGR) and the University of Illinois at Urbana-Champaign. Doña explains that “for decades ecologists have drawn attention to the urgency to understand the ecological role of parasites and protect as many species as possible from extinction ”. However, most animal conservation efforts exclude, ignore, or regard parasites as a problem: an animal is protected, but related parasites are removed before studying the parasite-host interaction.

An example of the relevance of parasites for the stability of ecosystems occurs with fish populations threatened with extinction, the Salvelinus leucomaenis japonicus. In the area they inhabit, there are parasites that affect crickets and grasshoppers and, when these insects are infected by the parasites, increases the probability by 20 that they jump into streams and the fish can devour them. Crickets and grasshoppers account for 60% of the food for these endangered fish.

This special volume includes a work led by Doña with Kevin Johnson from the University of Illinois (USA). In this work, methodologies of coevolutionary biology of symbionts have been integrated with the conservation perspective, in order to improve estimates of the probability of extinction of these species.

“In particular, in this work, we propose a new variable, the cofylogenetic extinction rate, which uses data from cofylogenetic analysis based on macroevolutionary events and which serves to obtain an estimate of the extinction probability of symbiotic organisms. Finally, we propose possible ways to develop this approach in order, in this way, to continue with the integration of coevolutionary biology and conservation biology ”, points out the researcher.

Conservation goals

The “Global Plan” of the special volume, led by Skylar Hopkins, from North Carolina State University, (USA) and Colin Carlson from Georgetown University, (USA) and in which Doña participates, raises twelve goals for the next decade. These are divided into four categories: data collection and synthesis; risk prioritization and measurement; conservation practice and education. Following this plan, changes in protocols for parasite conservation, conservation assessments for individual species, and increased capacity of organizations for parasite research and conservation may be seen.

“Thousands or millions of parasites could be negatively affected by global change and these losses could have cascades of consequences for the function and stability of ecosystems. However, it is not yet possible to fully quantify or address these issues given the existing data gap. In particular, most species of parasites have not yet been discovered or are not described, and of those known, very few have well-studied distributions or population sizes, ”explains Hopkins.

“And species have no name, we cannot conserve them”Carlson notes. In fact, one of the objectives that the work raises is to get to describe 50% of the total of these species.