Dr. Francisco Fontúrbel, an Associate Professor in the Biology Department at the Pontificia Universidad Católica de Valparaíso in Chile, discusses with us his recent publication in Functional Ecology, titled “Cryptic interactions revisited from ecological networks: mosses as a key link between trees and hummingbirds”, as well as the background of the research, and how the study raises new questions to be answered.

Francisco in the field, contemplating an endemic moss in the temperate rainforests of Southern Chile (credit Johana Villagra).
Francisco in the field, contemplating an endemic moss in the temperate rainforests of Southern Chile (credit Johana Villagra).

What’s your paper about?

In our paper, we used ecological networks to study the cryptic interactions between trees and mosses and between mosses and hummingbirds that build their nests with them. While ecological interactions are very important for community structuring and maintaining biodiversity, our knowledge about them is usually biased against inconspicuous species that may be playing a central role but are often ignored. And this is the case of mosses. Although mosses are quite abundant in temperate and boreal forests, our understanding of their ecological interactions is somewhat limited. We found that mosses have non-random associations with the trees that hold them. Furthermore, hummingbirds actively select some moss species to build their nests while ignoring other abundant moss species. We simulated the effects of removing certain tree species (which usually happens as a result of selective logging) on network topology and its cascade consequences on hummingbirds.

What is the background behind your paper?

Six years ago, we published a paper in Oikos reporting a mutualistic synzoochory (i.e., the deliberate transportation of plant propagules in the animal’s mouth with no ingestion) interaction between mosses and hummingbirds. The Green-backed Firecrown (Sephanoides sephaniodes) is the most common hummingbird species in Chile and the most important vertebrate pollinator of the southern South American temperate rainforest. In this first paper, we reported seven moss species in the nests, but Ancistrodes genuflexa was the most common, constituting up to 97% of the nest biomass. Still, it only represents 0.1% of the moss biomass in the forest. We were intrigued by this active selection pattern, and we further investigated the chemical and antimicrobial properties of A. genuflexa and other common moss species. We found that this little abundant moss species acts as a natural biocidal that the other mosses do not. We recently published these results in Ecology. This third paper rounds up the idea with the ecological networks, looking at the big picture.

A hummingbird in a living nest made of mosses and ferns (credit Felipe Rabanal).
A hummingbird in a living nest made of mosses and ferns (credit Felipe Rabanal).

Does this article raise any new research questions?

Maybe this article raises more questions than answers. Many unsolved mysteries deserve further study, for example, if moss-tree interactions are neutral for trees or they impose costs of holding large amounts of moss biomass.

What is the broader impact of your paper (outside of your specific species/study system)

This paper puts cryptic interactions in the spotlight. We all have an unconscious bias when choosing a study system. As a result of it, we usually overlook many inconspicuous species and focus our attention into a few charismatic species (‘the usual suspects’) that are well-studied. At the same time, we know virtually nothing about many other species. We used ecological networks to highlight the importance of mosses (the cryptic species) as a key link between trees and hummingbirds, but this general idea could be applied to any system as cryptic species are everywhere and they may be playing important roles in the community. This general idea could be applied to epiphytic ferns providing microhabitat for tardigrades or to ticks on migratory birds transporting rickettsia strains from one continent to another.

Why is it important?

Cryptic species and cryptic interactions are everywhere, but they usually go unnoticed. Therefore, their extinction may also go unnoticed, but the consequences on ecosystem functioning might be significant. The balance of nature is delicate, and such disruptions may have cascade effects on other species. In this paper, we simulated the impact of selective logging upon other components of the forest. Removing large trees directly affected moss diversity and biomass, and indirectly affected hummingbirds that use particular moss species for nest building, indicating nesting material selection is non-random and has little substitutability. Therefore, the extinction of a given moss (a particularly scarce one) would have devastating consequences on hummingbirds, which are the major vertebrate pollinator of these forests. Beyond the study system/species, these ideas may encourage others to think outside the box to improve management & conservation actions.

What are you currently working on?

I am currently working on the effects of anthropogenic disturbance and climate change on ecological interactions. The long-term goal of my research is to understand how biodiversity changes in different spatial and temporal scales as a result of human actions. Currently, I am using mistletoes as model species to understand the eco-evolutionary dynamics of plant-plant and plant-animal interactions in a changing world. In parallel, I am involved in two large projects about pollination, and side projects on animal and plant ecology in the Chilean temperate rainforests and the tropical forests of the Colombian central Andes.

What’s your current position?

I am an associate professor at the Pontificia Universidad Católica de Valparaíso in Chile. I am working at the Biology Department, leading the Integrative Ecology laboratory.

What project/article are you most proud of?

Uhmm… it is a difficult choice. I may say that my favourite article is a review entitled “Mistletoes in a changing world: a premonition of a non-analog future?” that was recently published in Botany.

Read “Cryptic interactions revisited from ecological networks: mosses as a key link between trees and hummingbirds” here!